Publications

Intrinsic factors such as female age and mating status have been found to affect female choosiness. However, as these factors are often confounded in the wild because mated females are usually older individuals, the relative influence of these two factors on female behaviour is unclear. Using a fully factorial design, we tested the relative effects of age and mating status of female field crickets (Gryllus pennsylvanicus Burmeister, 1838) on both (i) the probability that she would mate and (ii) her latency to mate. We found that virgin females were both more likely to mate and copulated more quickly than mated females, but female age had no significant effect on either the probability of mating or the latency to copulate. These results clearly show that mating status is more important in determining female mating behaviour than age. We suggest that previous work which showed an age effect on female choosiness in virgins alone might be of reduced relevance if most females do not remain unmated for long

Eddy covariance (EC) measurements have greatly advanced our knowledge of carbon exchange in terrestrial ecosystems. However, appropriate techniques are required to upscale these spatially discrete findings globally. Satellite remote sensing provides unique opportunities in this respect, but remote sensing of the photosynthetic light-use efficiency (ε), one of the key components of Gross Primary Production, is challenging. Some progress has been made in recent years using the photochemical reflectance index, a narrow waveband index centered at 531 and 570 nm. The high sensitivity of this index to various extraneous effects such as canopy structure, and the view observer geometry has so far prevented its use at landscape and global scales. One critical aspect of upscaling PRI is the development of generic algorithms to account for structural differences in vegetation. Building on previous work, this study compares the differences in the PRI: ɛ relationship between a coastal Douglas-fir forest located on Vancouver Island, British Columbia, and a mature Aspen stand located in central Saskatchewan, Canada. Using continuous, tower-based observations acquired from an automated multi-angular spectro-radiometer (AMSPEC II) installed at each site, we demonstrate that PRI can be used to measure ɛ throughout the vegetation season at the DF-49 stand (r2 = 0.91, p < 0.00) as well as the deciduous site (r2 = 0.88, p < 0.00). It is further shown that this PRI signal can be also observed from space at both sites using daily observations from the Moderate Resolution Imaging Spectro-radiometer (MODIS) and a multi-angular implementation of atmospheric correction (MAIAC) (r2 = 0.54 DF-49; r2 = 0.63 SOA; p < 0.00). By implementing a simple hillshade model derived from airborne light detection and ranging (LiDAR) to approximate canopy shadow fractions (αs), it is further demonstrated that the differences observed in the relationship between PRI and ε at DF-49 and SOA can be attributed largely to differences in αs. The findings of this study suggest that algorithms used to separate physiological from extraneous effects in PRI reflectance may be more broadly applicable and portable across these two climatically and structurally different biome types, when the differences in canopy structure are known.

The high-resolution infrared spectrum of deuterated fluoroform (DCF3) was studied in the 700 and1200 cm1 regions, with the aim of assigning and analyzing the m4 CF3 asymmetric stretching vibration.The Fermi-type anharmonic coupling between the m4 = 1 and m3 = m6 = 1 rovibrational levels, already men-tioned in an early work of Ruoff et al. [Spectrochimica Acta Part A 31A (1975) 1099–1100], was studiedhere for the first time under high resolution. Assignments in the m3 + m6/m4 band system were confirmedand extended by the identification of the m3 + m6  m6 and m4–m6 bands in the 700 cm1 region, the latterbeing enhanced near the Fermi crossings of the studied levels. Data from both the hot and differencebands were included in the analysis. The close separation of the studied vibrational levels of about14.8 cm1 produces a large variety of resonance crossings which involve levels with Dk ¼ 0; ... ; 6.Besides the Fermi (Dk ¼ 0; Dl ¼ 0) and Coriolis (Dk ¼1; Dl ¼2) resonances, they were accountedfor by inclusion of additional higher-order (Dk ¼2; Dl ¼2 and Dk ¼3; Dl ¼ 0) interaction termsbetween the vibrational states. The least-squares fit of more that 16,000 vibration-rotation transitionsprovides a quantitative reproduction of data in all bands.

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Buddhism has been practiced in Canada for more than a century and in recent years has grown dramatically. Immigrant communities construct temples in Canada's urban centres, the Dalai Lama is one of the world's most recognizable figures, and Buddhist ideas and practices such as meditation, vegetarianism, and non-violence are increasingly a part of mainstream culture. More native-born Canadians are turning to Buddhism now than ever before. The most comprehensive study of Buddhism in Canada to date, Wild Geese offers a history of the religion's evolution in Canada, surveys the diverse communities and beliefs of Canadian Buddhists, and presents biographies of Buddhist leaders. The essays cover a broad range of topics, including Chinese, Tibetan, Lao, Japanese, Korean, and Vietnamese Buddhisms, critical reflections on Buddhism in the West, census data on the growth of the religion, and analysis of the global context for the growth of Buddhism in Canada. Presenting a sweeping portrait of a crucial part of the multicultural mosaic, Wild Geese is essential reading for anyone interested in religious life in Canada. Illustrations • xiTables • xiiiConventions (Romanization and Use of Diacritics) • xvAcknowledgments • xix Introduction • 3 PART ONE: OPENINGSHow Do We Study Buddhism in Canada? • 12Victor Sogen Hori Asian Reformers, Global Organizations: An Exploration of the Possibility of a “Canadian Buddhism” • 39Alexander Soucy PAR T TWO: HISTORIES AND OVERVIEWSLooking East: Japanese Canadians and Jodo Shinshu Buddhism, 1905-1970 • 62Terry Watada Buddhism after the Seventies • 84Henry C . H . Shui Buddhism in Canada: A Statistical Overview from Canadian Censuses, 1981-2001 • 111Peter Beyer PART THREE: FROM GLOBAL TO LOCALJodo Shinshu in Southern Alberta: From Rural Raymond to Amalgamation • 134John S . Harding That Luang: The Journey and Relocation of Lao Buddhism to Canada • 168Marybeth White Transforming Ordinary Life: Turning to Zen Buddhism in Toronto • 187Patricia Q . Campbell The Woodenfish Program: Fo Guang Shan, Canadian Youth, and a New Generation of Buddhist Missionaries • 210Lina Verchery Shambhala International: The Golden Sun of the Great East • 236Lynn P. Eldershaw PART FOUR: FROM LOCAL TO GLOBALGlobalization and Modern Transformation of Chinese Buddhism in Three Chinese Temples in Eastern Canada • 270Tannie Liu The Tzu Chi Merit Society from Taiwan to Canada • 295André La Liberté and Manuel Litalien A Relationship of Reciprocity: Globalization, Skilful Means, and Tibetan Buddhism in Canada • 321Sarah F. Haynes PART FIVE: LIVESAlbert Low: A Quest for a Truthful Life • 348Mauro Peressini Suwanda H.J. Sugunasiri: Buddhist • 377Victor Sogen Hori and Janet McLellan Conclusion • 400Bibliography • 407Contributors • 431Index • REVIEWS: "This very welcome study of Buddhism in Canada fills a gap in current scholarship and brings some order to an unsystematic field of current research." CHOICE "Wild Geese has an abundance of information that has been unavailable until now. The volume is provocative. It asks questions that are both stimulating and critical and the answers provided will immensely impact the currently emerging inquiries about Buddhism in Canada. I highly recommend this book to anyone interested in Buddhism. It is a deep breath in, and a deep breath out." Charles Prebish, Redd Chair in Religious Studies, Utah State University "Wild Geese critically deconstructs the concepts presently applied to Buddhism in the West and builds a foundation for further study. The anthology ties the culture of Buddhism in Canada to the international evolution of Buddhism. As a sweeping ... analysis of the Buddhist institutions in Canada, and a call to elucidate issues standing in the way of further research, it is a fine start to a burgeoning field of study." Montreal Review of Books "For those, interested in Buddhism in Canada, Wild Geese is required reading. And even those who focus strongly on Buddhism in America should give Wild Geese their attention, as it will help them to put their studies into a more North American focus, and perhaps help them discern what is American about their subjects, what is North American, and what belongs to a modern world-spanning flow of Buddhist movements and developments." Journal of Global Buddhism "The editors have assembled not only unquestionably the best survey of Buddhism in Canada, but arguably the new standard for books on Buddhism in all of North America. Scholars of religion in North America will be usefully provoked by this book. Scholars of Buddhism in the West simply must read it." Religious Studies Review

In the title compound, C5H8N3+center dot Cl-, the cation and the anion lie on a mirror plane and are hydrogen bonded in a three-dimensional network via the H atoms of the two hydrazine N atoms. The pyridine N atom is protonated and hydrogen bonded to the terminal hydrazine N atom.

The unsaturated redox-active cluster [Pd(3)(dppm)(3)(CO)](n+) (n = 0,1, or 2) reacts with ethylene dicarboxylic esters and a variety of terminal acetylenes (but not PhC CPh) in all three charge states. In particular, the radical cations [Pd(3)(dppm)(3)(CO)(RC CR')](+) can be produced by several routes: one-electron electrochemical reduction of the dication adducts, comproportionation of the neutral and dicationic adducts, as well as the direct complexation of alkyne to the known radical cation [Pd(3)(dppm)(3)(CO)](+). Compared with the latter, each of the adducts have significantly extended lifetimes and classify as persistent radicals in solution. The alkyne adducts have been characterized by voltammetry (cyclic and rotating disk electrode), by UV-vis titrations and by MALDI-TOF mass spectra from dithranol matrices. Isotropic solution EPR spectra of the adducts with R = R' = MeOC(O) and EtOC(O), as well as those with R' = H and R = C(6)H(5), FC(6)H(4), HC CC(6)H(4), and EtO have been obtained. Full line shape fitting simulations demonstrate that all display coupling to six different (31)P (I = 1/2) and to one to three (106)Pd (I = 5/2) nuclei. The A((31)P) values range from a low of 3.0 x 10(4) to a high of 180.5 x 10(4) cm(-1); this variation is caused by changes in the contribution of P s orbitals to the SOMO resulting from structural distortions of the Pd(3)P(6) core upon alkyne coordination.

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Hippocampal inputs to the nucleus accumbens (NA) have been proposed to implement a gating mechanism by driving NA medium spiny neurons (MSNs) to depolarized up states that facilitate action potential firing in response to brief activation of the prefrontal cortex (PFC). Brief PFC stimulation alone, on the other hand, could not drive NA up states. As these studies were conducted using single-pulse PFC stimulation, it remains possible that PFC activation with naturalistic, bursty patterns can also drive up states in NA MSNs. Here, we assessed NA responses to PFC stimulation with a pattern similar to what is typically observed in awake animals during PFC-relevant behaviors. In vivo intracellular recordings from NA MSNs revealed that brief 20-50 Hz PFC stimulus trains evoked depolarizations that were similar to spontaneous up states in NA MSNs and were sustained beyond stimulus offset. Similar train stimulation of corticoaccumbens afferents in a parasagittal slice preparation evoked large amplitude depolarizations in NA MSNs that were sustained during stimulation but decayed rapidly following stimulation offset, suggesting that activation of cortical afferents can drive MSN depolarizations but other mechanisms may contribute to sustaining up states. These data suggest that NA MSNs integrate temporal features of PFC activation and that the NA gating model can be reformulated to include a PFC-driven gating mechanism during periods of high PFC firing, such as during cognitively demanding tasks. Synapse 63:173-180, 2009. (c) 2008 Wiley-Liss, Inc.

The structure of the title compound, [Mg-2(C4H9)(C14H18NO)(3)], contains two Mg atoms bridged by two mu(2)-O atoms from two of the three ketiminate ligands, while the third ketiminate is strictly chelating to one of the Mg atoms, which is thereby five-coordinate. In place of a chelating ligand, the second Mg atom is ligated by a single terminal n-butyl group and thus is four-coordinate. This is, so far, the only structurally characterized mixed magnesium ketiminate-alkyl cluster. The geometry at the first Mg atom is close to trigonal-bipyramidal with one chelating and one bridging O atom in the axial positions and two chelating N and one bridging O atom in the equatorial positions. The geometry at the second Mg atom is very distorted from tetrahedral, with an O-Mg-C angle of 131.0 (1)degrees.

In this study, we have calculated the broadening and first order line mixing parameters for over 100transitions in the 30012 00001 and 30013 00001 bands of carbon dioxide. The calculations wereperformed over the 193–323 K temperature range for pure CO2 and lean mixtures of CO2 and air. Theelements of the relaxation matrices were calculated at the appropriate physical conditions using theExponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws. We have compared ourcalculated low pressure line mixing parameters and the broadening coefficients with experimentalresults from two previous studies in our group available at 217, 234, 258 and 296 K. At all temperatures,the calculated broadening coefficients were also compared with those available in the HITRAN database. 2009 Elsevier Inc. All rights reserved

Basal ganglia circuits are organized as parallel loops that have been proposed to compete in a winner-take-all fashion to determine the appropriate behavioral outcome. However, limited experimental support for strong lateral inhibition mechanisms within striatal regions questions this model. Here, stimulation of the prefrontal cortex (PFC) using naturally occurring bursty patterns inhibited firing in most nucleus accumbens (NA) projection neurons. When an excitatory response was observed for one stimulation site, neighboring PFC sites evoked inhibition in the same neuron. Furthermore, PFC stimulation activated interneurons, and PFC-evoked inhibition was blocked by GABA(A) antagonists in corticoaccumbens slice preparations. Thus bursting PFC activity recruits local inhibition in the NA, shaping responses of projection neurons with a topographical arrangement that allows inhibition among parallel corticoaccumbens channels. The data indicate a high order of information processing within striatal circuits that should be considered in models of basal ganglia function and disease.

In this study, we sampled yellow perch from three lakes along a metal-contamination gradient and examined their olfactory ability in response to conspecific chemical alarm cues and metal-binding characteristics of their olfactory epithelium (OE). We measured the electrophysiological response at the OE, tested their antipredator behaviour and measured neuronal density at the olfactory rosette and bulb. Yellow perch from contaminated lakes exhibited significantly larger electrophysiological responses to alarm cues than clean lake fish, but showed no antipredator behaviour contrary to clean lake fish. Neuron density did not differ at either the olfactory rosette or bulb between clean and contaminated fish. Unlike fishes raised under laboratory or aquaculture settings, fish from contaminated lakes possessed a functional OE after metal exposure, but similar to laboratory/aquaculture fishes, yellow perch did not exhibit olfactory-mediated behaviours. Thus, wild fish from contaminated lakes can detect chemical stimuli but olfactory signal processing is disrupted which could alter ecological functioning.

Voltammetric studies of S2N2 employing both cyclic voltammetry (CV) and rotating disk electrode (RDE) methods on GC electrodes at room temperature (RT) revealed two irreversible reduction processes at about -1.4 V and -2.2 V in CH3CN, CH2Cl2, and tetrahydrofuran (vs ferrocene) and no observable oxidation processes up to the solvent limit when the scan is initially anodic. However, aftercycling the potential through -1.4 V, two new couples appear near -0.3 V and -1.0 V due to [S3N3](-/0) and [S4N4](-/0) respectively. The diffusion coefficient D for S2N2 was determined to be 9.13 x 10(-6) cm(2) s(-1) in CH2Cl2 and 7.65 x 10(-6) cm(2) s(-1) in CH3CN. Digital modeling of CVs fits well to a mechanism in which [S2N2](-center dot) couples rapidly with S2N2 to form [S4N4](-center dot), which then decomposes to [S3N3](-). In situ electron paramagnetic resonance (EPR) spectroelectrochemical studies of S2N2 in both CH2Cl2 and CH3CN resulted in the detection of strong EPR signals from [S4N4](-center dot) when electrolysis is conducted at -1.4 V; at more negative voltages, spectra from transient adsorbed radicals are observed. In moist solvent or with added HBF4, a longer-lived spectrum is obtained due to the neutral radical [S2N2H](-)center dot, identified by simulation of the EPR spectrum and density functional theory (DFT) calculations. The chemical reduction Of S2N2 with Na[C10H8] or Na[Ph2CO] produces [Na(15-crown-5)][S3N3], while reduction with cobaftocene gives [Cp2Co][S3N3]. The X-ray structure of the former reveals a strong interaction (Na center dot center dot center dot N = 2,388(5) angstrom) between the crown ether-encapsulated Na+ caton and one of the nitrogen atoms of the essentially planar six-membered cyclic anion [S3N3](-).

Voltammetric studies Of S4N4 employing both cyclic (CV) and rotating disk (RDE) methods in CH2Cl2 at a glassy carbon electrode reveal a one-electron reduction at -1.00 V (versus ferrocene/ferrocenium), which produces a second redox couple at -0.33 V, confirmed to be the electrochemically generated [S3N3](-) by CV studies on its salts. Diffusion coefficients (CH2Cl2/0.4 M [(Bu4N)-Bu-n][PF6]) estimated by RDE methods: S4N4, 1.17 x 10(-5) cm(2) s(-1); [S3N3](-), 4.00 x 10(-6) cm(2) s(-1). Digital simulations of the CVs detected slow rates of electron transfer for both couples and allowed for a determination of rate constants for homogeneous chemical reaction steps subsequent to electron transfer. The common parameters (k(f1) = 2.0 +/- 0.5 s(-1), k(s1), = 0.034 +/- 0.004 cm s(-1) for [S4N4](-/0); k(f2) = 0.4 +/- 0.2 s(-1), k(s2) = 0.022 +/- 0.005 cm s(-1) for [S3N3](-/0) at T= 21 +/- 2 degrees C) fit well to a "square-scheme" mechanism over the entire range of data with first order decay of both redox products. An alternate model could also be fit wherein [NS](center dot) liberated in the first step reacts with formed [S3N3](center dot) to reproduce S4N4 with an apparent second order rate constant k(f2)' = 1.1 +/- 0.3 x 10(3) M-1 s(-1). The crystal structure of [PPN][S3N3] was determined by X-ray crystallography indicating the solvation of the anion by 1 equiv of methanol. The generated [S4N4](-center dot) radical anion was detected by the Simultaneous Electrochemical Electron Paramagnetic Resonance (SEEPR) method to give: (a) [S-32(4) N-14(4)](-center dot), 9 lines, a(N-14) = 0.118 mT; (b) [(S4N4)-S-32-N-15](-center dot), 5 lines, a(N-15) = 0.164 mT; (C) [(S4N4)-S-33-N-14](-center dot), estimated a(N-14) = 0.118, a(S-13 = 0.2 mT); g = 2.0008(1). Equivalence of S-33 hyperfine splittings is consistent with dynamic averaging of the C-2v geometry in solution. High-level electronic structure calculations provide evidence for an open-shell doublet triradicaloid character to the ground state wave function Of [S3N3](center dot).

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The high-resolution Fourier transform spectrum of the m8 CO-stretching band of CH318OH between 900and 1100 cm1 has been recorded at the Canadian Light Source (CLS) synchrotron facility in Saskatoon,and the majority of the torsion–rotation structure has been analyzed. For the mt = 0 torsional ground state,subbands have been identified for K values from 0 to 11 for A and E torsional symmetries up to J valuestypically well over 30. For mt =1, A and E subbands have been assigned up to K = 7, and several mt = 2 sub-bands have also been identified. Upper-state term values determined from the assigned transitions usingthe Ritz program have been fitted to J(J + 1) power-series expansions to obtain substate origins and sets ofstate-specific parameters giving a compact representation of the substate J-dependence. The mt = 0 sub-band origins have been fitted to effective molecular constants for the excited CO-stretching state and atorsional barrier of 377.49(32) cm1 is found, representing a 0.89% increase over the ground-state value.The vibrational energy for the CO-stretch state was found to be 1007.49(7) cm1. A number of subband-wide and J-localized perturbations have been seen in the spectrum, arising both from anharmonic andCoriolis interactions, and several of the interacting states have been identified. 2009 Elsevier Inc. All rights reserved.

This paper demonstrates that the appropriate econometric technique of testing for the effect of regional integration on bilateral trade is to augment the standard gravity model with country specific dummies instead of regional integration dummies. Using data on bilateral trade between Tanzania and her 23 trading partners over the period 1980-2004, the paper reports three important results. First, contrary to results from the traditional approach, estimates from the new econometric technique indicate that both the EU and the EAC have had moderate trade creation effects on Tanzania's bilateral trade. Second, I find that Tanzania's non-traditional trading partners such as Japan, India, Singapore, Hong Kong and the USA are relatively more opened to Tanzania's exports. Third, the results also indicate that whereas it is difficult for Tanzania's exports to penetrate foreign markets, foreign goods easily penetrate Tanzania's market. The policy implication is that the government should continue with its efforts to strengthen the EAC, and to gain more exports market to the non-traditional trading partners, if the export growth development strategy is to become a reality in Tanzania.

This paper describes the status of the 2008 edition of the HITRAN molecularspectroscopic database. The new edition is the first official public release since the2004 edition, although a number of crucial updates had been made available onlinesince 2004. The HITRAN compilation consists of several components that serve as inputfor radiative-transfer calculation codes: individual line parameters for the microwavethrough visible spectra of molecules in the gas phase; absorption cross-sections formolecules having dense spectral features, i.e. spectra in which the individual lines arenot resolved; individual line parameters and absorption cross-sections for bands in theultraviolet; refractive indices of aerosols, tables and files of general properties associatedwith the database; and database management software. The line-by-line portion of the database contains spectroscopic parameters for 42 molecules including many of their isotopologues.

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Why do people study religion? How have they studied it in the past? How do we study religion today? Is the academic study of religion the same as religious education? These and many other questions are addressed in this engaging introduction to the discipline of religious studies, written by two experienced university teachers. The authors have crafted this book to familiarize novice students with key concepts and terminology in the study of religion. More advanced students will find a varied array of theoretical perspectives and methodological approaches to the field. Topics include: definitions of religionperspectives in the study and teaching of religionhow religion began to be studied: traditional perspectives – philosophical and theologicalhow people experience religion: perspectives in the study of religious consciousness and perception – phenomenological and psychologicalstudying religion within communities: Social and cultural perspectives – anthropological, sociological, political and economicjudging religion: critical perspectives –feminist approaches, the interaction of popular literature and religioncontextual perspectives – historical and comparative. The book encourages students to think critically about the theories and methods presented. Students will find arguments for the strengths and limitations of these approaches, understand connections among religious studies and other intellectual movements, and develop their own ideas of how they might want to go about the study of religion. Summary boxes, a timeline, a glossary and other pedagogic aids help students grasp key concepts, along with a companion website at www.sastor.com. 1. Defining Religion 2. How Religion Began To Be Studied: Traditional Perspectives 3. Studying Religion Within Communities: Social and Cultural Perspectives 4. How People Experience Religion: Perspectives in the Study of Religious Consciousness and Perception 5. Judging Religion: Critical Perspectives and Evaluations 6. Studying Religion in Context: Perspectives and Conclusion. Chronology of Significant Persons and Seminal Texts. Glossary

Lorentz air-broadened half widths, pressure-induced shifts and their temperaturedependences have been measured for over 430 transitions (allowed and forbidden) inthe n4 band of 12CH4 over the temperature range 210–314K. A multispectrum non linearleast squares fitting technique was used to simultaneously fit a large number of high-resolution (0.006–0.01cm1) absorption spectra of pure methane and mixtures ofmethane diluted with dry air. Linemixing was detected for pairs of A-, E-, and F-speciestransitions in the P- and R-branch manifolds and quantified using the off-diagonalrelaxation matrix elements formalism. The measured parameters are compared toair- and N2-broadened values reported in the literature for the n4 and other bands. Thedependence of the various spectral line parameters upon the tetrahedral symmetryspecies and rotational quantum numbers of the transitions is discussed. All data used inthe present work were recorded using the McMath–Pierce Fourier transform spectro-meter located at the National Solar Observatory on Kitt Peak.Published by Elsevier Ltd.

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Reward intake optimization requires a balance between exploiting known sources of rewards and exploring for new sources. The prefrontal cortex (PFC) and associated basal ganglia circuits are likely candidates as neural structures responsible for such balance, while the hippocampus may be responsible for spatial/contextual information. Although studies have assessed interactions between hippocampus and PFC, and between hippocampus and the nucleus accumbens (NA), it is not known whether 3-way interactions among these structures vary under different behavioral conditions. Here, we investigated these interactions with multichannel recordings while rats explored an operant chamber and while they performed a learned lever-pressing task for reward in the same chamber shortly afterward. Neural firing and local field potentials in the NA core synchronized with hippocampal activity during spatial exploration, but during lever pressing they instead synchronized more strongly with the PFC. The latter is likely due to transient drive of NA neurons by bursting prefrontal activation, as in vivo intracellular recordings in anesthetized rats revealed that NA up states can transiently synchronize with spontaneous PFC activity and PFC stimulation with a bursting pattern reliably evoked up states in NA neurons. Thus, the ability to switch synchronization in a task-dependent manner indicates that the NA core can dynamically select its inputs to suit environmental demands, thereby contributing to decision-making, a function that was thought to primarily depend on the PFC.

Field studies were initiated in 1999 at Scotty Creek in the lower Liard River basin, NWT, Canada, to improve understanding of and ability to predict the major water fluxes and storage processes within a wetland-dominated zone of the discontinuous permafrost region. This paper synthesises a decade of published and unpublished research at Scotty Creek for the purpose of presenting the major factors that should be considered by water scientists and managers as a basis for modelling and management strategies. Five main topics are covered: (1) peatlands of lower Liard River valley; (2) hydrological characteristics of permafrost plateaus, flat bogs, and channel fens; (3) runoff generation on permafrost plateaus; (4) conceptual model of peatland hydrology; and (5) climate warming and implications for basin runoff. This synthesis offers a practical understanding of the hydrology of wetland-dominated basins with discontinuous permafrost. It also offers insight into how landscape changes resulting from climate or human disturbances may influence the basin hydrograph.

Understanding the influence of within-pixel land cover heterogeneity is essential for the extrapolation of measured and modeled CO2 fluxes from the canopy to regional scales using remote sensing. Airborne light detection and ranging (lidar) was used to estimate spatial and temporal variations of gross primary production (GPP) across a jack pine chronosequence of four sites in Saskatchewan, Canada for comparison with the Moderate Resolution Imaging Spectroradiometer (MODIS) GPP product. This study utilizes high resolution canopy structural information obtained from airborne lidar to bridge gaps in spatial representation between plot, eddy covariance (EC), and MODIS estimates of vegetation GPP. First we investigate linkages between canopy structure obtained from measurements and light response curves at a jack pine chronosequence during the growing season of 2004. Second, we use the measured canopy height and foliage cover inputs to create a structure-based GPP model (GPPLandsberg) which was tested in 2005. The GPP model is then run using lidar data (GPPLidar) and compared with eight-day cumulative MODIS GPP (GPPMODIS) and EC observations (GPPEC). Finally, we apply the lidar GPP model at spatial resolutions of 1 m to 1000 m to examine the influence of within-pixel heterogeneity and scaling (or pixel aggregation) on GPPLidar. When compared over eight-day cumulative periods throughout the 2005 growing season, the standard deviation of differences between GPPlidar and GPPMODIS were less than differences between either of them and GPPEC at all sites. As might be expected, the differences between pixel aggregated GPP estimates are most pronounced at sites with the highest levels of spatial canopy heterogeneity. The results of this study demonstrate one method for using lidar to scale between eddy covariance flux towers and coarse resolution remote sensing pixels using a structure-based Landsberg light curve model.

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A series of phenyl-substituted bis(isobenzofuran)s in which the furan moieties are linked by 1,3-phenylene, 1,4-phenylene, or 4,4'-biphenylene linkers have been prepared in only two steps. They are comparable to diphenylisobenzofuran in their absorption and luminescent properties, their electrochemistry, and their reactivity. Their degree of similarity to diphenylisobenzofuran was found to depend significantly on the nature of the linking group. Diels-Alder reaction of the title compounds and subsequent aromatization gave very rapid access to penta- or hexa-aryl products.

Variability in three Pacific teleconnection patterns are examined to see if net carbon exchange at a low-elevation, old-growth forest is affected by climatic changes associated with these periodicities. Examined are the Pacific Decadal Oscillation (PDO), Pacific/North American Oscillation (PNA) and El Niño-Southern Oscillation (ENSO). We use 9 years of eddy covariance CO2, H2O and energy fluxes measured at the Wind River AmeriFlux site, Washington, USA and 8 years of tower-pixel remote sensing data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to address this question. We compute a new Composite Climate Index (CCI) based on the three Pacific Oscillations to divide the measurement period into positive- (2003 and 2005), negative- (1999 and 2000) and neutral-phase climate years (2001, 2002, 2004, 2006 and 2007). The forest transitioned from an annual net carbon sink (NEP=+217 g C m−2 yr−1, 1999) to a source (NEP=−100 g C m−2 yr−1, 2003) during two dominant teleconnection patterns. Net ecosystem productivity (NEP), water use efficiency (WUE) and light use efficiency (LUE) were significantly different (P<0.01) during positive (NEP=−0.27 g C m−2 day−1, WUE=4.1 mg C g−1 H2O, LUE=0.94 g C MJ−1) and negative (NEP=+0.37 g C m−2 day−1, WUE=3.4 mg C g−1 H2O, LUE=0.83 g C MJ−1) climate phases. The CCI was linked to variability in the MODIS Enhanced Vegetation Index (EVI) but not to MODIS Fraction of absorbed Photosynthetically Active Radiation (FPAR). EVI was highest during negative climate phases (1999 and 2000) and was positively correlated with NEP and showed potential for using MODIS to estimate teleconnection-driven anomalies in ecosystem CO2 exchange in old-growth forests. This work suggests that any increase in the strength or frequency of ENSO coinciding with in-phase, low frequency Pacific oscillations (PDO and PNA) will likely increase CO2 uptake variability in Pacific Northwest conifer forests.

The heterotrinuclear complexes, [(CpTiCl(2)Cp-PPh(2))(2)Cu](+) (2) (as PF(6)(-) salt) and [CpTiCl(2)Cp-PPh(2)](2)CuCl (3), containing two electron-poor Ti(IV) fragments and one electron-rich Cu(I) center, and a tetrametallic species, [(CpTiCl(2)Cp-PPh(2))Cu(mu-Cl)](2) (4), were synthesized and characterized. The trinuclear nature of 2 and 3 was demonstrated by X-ray crystallography for which the three metallic centers are held together by two CpPPh(2) ligands. Weak Cl center dot center dot center dot Cu interactions are noted in 3, whereas two stronger Cl-Cu bridges are depicted in the cationic complex 2. The tetranuclear complex 4 contains two Cu atoms bridged together by two chloride ligands and connected to one Ti atom by one CpPPh(2) ligand and one mu-Cl ligand. Despite the short distances in the Ti-Cl-Cu bridges, notably in 2 and 4, the NMR spectra reveals evidence of fluxion in solution attributed to the lability of the mu-Cl ligands. Electrochemical experiments performed on 2 (rotating disk electrode and cyclic voltammograms) demonstrated the presences of two successive 1-electron reductions generating a first structurally unsymmetrical paramagnetic species [(CpTiCl(2)CP-PPh(2))(2)Cu](0) (2') confidently characterized by electron paramagnetic resonance (EPR) as a Ti(III)-Cu(I)-Ti(IV) system, and a second one, which is tentatively assigned to a symmetric neutral complex formulated as [CpTiClCp-PPh(2)](2)CuCl (5) with an EPR signature indistinguishable from that of 2' (i.e., Ti(III)-Cu(I)-Ti(III) system with a similar electronic environment). Density functional theory (DFT) computations examining the nature of the frontier orbitals and the geometry confirmed the presence and lack of symmetry in 2 and 2', respectively. The detection of chemical/electrochemical mechanisms in the electrochemical studies provides a clear explanation for the stepwise reduction behavior in these systems through chloride ligand transfer from Ti to Cu prior to the first reduction step. This transfer process is fully reversible upon re-oxidation. The electrochemical properties of complexes 3 and 4 are also reported.

Isobenzofurans (IBF)s have seen widespread use in the synthesis of both natural products and polycyclic aromatic hydrocarbons. There are few examples that have two IBF entities linked in a fused aromatic ring system. Here we present the synthesis and characterization of a bis(IBF), 2,7-di(tert-butyl)pyreno[4,5-c:9,10-c']difuran. Reaction with bis(maleimide) dienophiles gives pyrenophanes. The solid-state structures of the bis(IBF) and two cyclophanes are discussed.

In this study, 39 high-resolution spectra of pure and air-broadened CO2 recorded at temperatures between 215 and294 K were analyzed using a multispectrum nonlinear least-squares technique to determine temperature dependences of air-broadened Lorentz half-width and air-induced pressure shift coefficients for over 100 individual 12C16O2 transitions in the30012/00001 (at 6348 cm–1) and 30013/00001 (at 6228 cm–1) bands. Data were recorded with two different Fourier trans-form spectrometers (Kitt Peak FTS at the National Solar Observatory in Arizona and the Bomem FTS at NRC, Ottawa), withabsorption path lengths ranging between 25 and 121 m. The sample pressures varied between 11 torr (pure CO2) and 924 torr(CO2-air) with volume mixing ratios of CO2 in air between*1.5% and 11% (1 torr = 133.322 4 Pa). To minimize systematicerrors and increase the accuracy of the retrieved parameters, a constrained multispectrum nonlinear least-squares fitting tech-nique was used to include theoretical quantum mechanical expressions for the rovibrational energies and intensity parametersrather than retrieving the individual positions and intensities line by line. The results suggest no detectable vibrational de-pendence for the temperature dependences for the air-broadened Lorentz half-width coefficients and the air-induced pressureshift coefficients. The half-width coefficients and temperature dependence exponents were modeled using semiclassical cal-culations based upon the Robert–Bonamy formalism. A good agreement is seen between the measurements and theoreticalcalculations. Beyond |m| = 26, a simple scaling factor (0.96) has been applied to the calculated half-width coefficients tomatch the experimental measurements.

In this study, 39 high-resolution spectra of pure and air-broadened CO2 recorded at temperatures between 215 and294 K were analyzed using a multispectrum nonlinear least-squares technique to determine temperature dependences of air-broadened Lorentz half-width and air-induced pressure shift coefficients for over 100 individual 12C16O2 transitions in the30012/00001 (at 6348 cm–1) and 30013/00001 (at 6228 cm–1) bands. Data were recorded with two different Fourier trans-form spectrometers (Kitt Peak FTS at the National Solar Observatory in Arizona and the Bomem FTS at NRC, Ottawa), withabsorption path lengths ranging between 25 and 121 m. The sample pressures varied between 11 torr (pure CO2) and 924 torr(CO2-air) with volume mixing ratios of CO2 in air between*1.5% and 11% (1 torr = 133.322 4 Pa). To minimize systematicerrors and increase the accuracy of the retrieved parameters, a constrained multispectrum nonlinear least-squares fitting tech-nique was used to include theoretical quantum mechanical expressions for the rovibrational energies and intensity parametersrather than retrieving the individual positions and intensities line by line. The results suggest no detectable vibrational de-pendence for the temperature dependences for the air-broadened Lorentz half-width coefficients and the air-induced pressureshift coefficients. The half-width coefficients and temperature dependence exponents were modeled using semiclassical cal-culations based upon the Robert–Bonamy formalism. A good agreement is seen between the measurements and theoreticalcalculations. Beyond |m| = 26, a simple scaling factor (0.96) has been applied to the calculated half-width coefficients tomatch the experimental measurements.

Four LiDAR-based models of canopy fractional cover (FCLiDAR) have been tested against hemispherical photography fractional cover measurements (FCHP) and compared across five ecozones, eight forest species and multiple LiDAR survey configurations. The four models compared are based on: i) a canopy-to-total first returns ratio (FCLiDAR(FR)) method; ii) a canopy-to-total returns ratio (FCLiDAR(RR)); iii) an intensity return ratio (FCLiDAR(IR)); and iv) a Beer's Law modified (two-way transmission loss) intensity return ratio (FCLiDAR(BL)). It is found that for the entire dataset, the FCLiDAR(RR)model demonstrates the lowest overall predictive capability of overhead FC (annulus rings 1–4) (r2 = 0.70), with a slight improvement for the FCLiDAR(FR) model (r2 = 0.74). The intensity-based FCLiDAR(IR) model displays the best results (r2 = 0.78). However, the FCLiDAR(BL) model is considered generally more useful (r2 = 0.75) because the associated line of best fit passes through the origin, has a slope near unity and produces a mean estimate of FCHP within 5%. Therefore, FCLiDAR(BL) requires the least calibration across a broad range of forest cover types. The FCLiDAR(FR) and FCLiDAR(RR) models, on the other hand, were found to be sensitive to variations in both canopy height and sensor pulse repetition frequency (or pulse power); i.e. changing the repetition frequency led to a systematic shift of up to 11% in the mean FCLiDAR(RR) estimates while it had no effect on the intensity-based FCLiDAR(IR) or FCLiDAR(BL) models. While the intensity-based models were generally more robust, all four models displayed at least some sensitivity to variations in canopy structural class, suggesting that some calibration of FCLiDAR might be necessary regardless of the model used. Short (< 2 m tall) or open canopy forest plots posed the greatest challenge to accurate FC estimation regardless of the model used.

1.†Inducible defences may be temporary and favoured where predation is intermittent and have been demonstrated in several invertebrates and vertebrates when prey detect chemical cues (kairomones) released by predators. Daphnia pulex (a water flea) exposed to Chaoborus (midge larvae) kairomones produce small neckteeth on the dorsal surface of the head as a defence against this gape-limited predator and survive better in the presence of Chaoborus. Recent studies have shown that waterborne copper (Cu) impairs the induction of neckteeth which could lead to lower survival. 2.†Here, we examined the effects of Cu on morphological changes and shifts in life-history traits in D. pulex exposed to kairomone from Chaoborus americanus. We exposed D. pulex mothers to chemical cues of C. americanus fed on either D. pulex neonates or on brine shrimp Artemia salina, the same Chaoborus cues combined with an environmentally relevant concentration of copper (10†03BCg†L22121), or dechlorinated tap water. We examined several morphological characteristics of neonates and life-historical characteristics of adults as well as assessing survival of neonates by staging encounters with predators. 3.†Neonates from mothers exposed to kairomone plus copper had fewer and shorter neckteeth than neonates from mothers exposed to kairomone alone. Moreover, neonates exposed to Cu had lower survival during encounters with predators than neonates exposed to kairomone without Cu. 4.†Adult female Daphnia exposed to kairomones released more neonates within the first 24†h of brood release and emptied their brood pouches quicker than mothers not exposed to kairomones, irrespective of the presence of Cu. 5.†Impairment by metals of morphological defences in zooplankton could lead to a decline in population density and alter community structure.

We present a line shape analysis of the P(2) and P(7) transitions of CO broadened by Xe in the fundamentalband. The spectra were recorded at 349 K using a difference frequency laser spectrometer. To obtain information on theinfluence of Dicke narrowing, relaxation speed dependence, and line mixing effects, several models for implementation ofDicke narrowing and (or) speed-dependent effects are discussed. From experimental data analysis, we conclude that lineshape models taking into account the Dicke effect only fail in the high pressure regime and lead to optical diffusion pa-rameters that are much larger than the kinetic diffusion ones. On the contrary, a fair interpretation of data is obtained fromspeed-dependent models, so that it is possible to derive a quantitative estimate of optical diffusion effects that appearmuch smaller than the kinetic diffusion ones. Xe-broadening coefficients of CO lines in the fundamental band at 297 and349 K are calculated from a semiclassical formalism involving successively two intermolecular potentials, the atom-atomLennard-Jones model, and a three-term expansion of Legendre polynomials with four adjustable parameters.

We present a line shape analysis of the P(2) and P(7) transitions of CO broadened by Xe in the fundamentalband. The spectra were recorded at 349 K using a difference frequency laser spectrometer. To obtain information on theinfluence of Dicke narrowing, relaxation speed dependence, and line mixing effects, several models for implementation ofDicke narrowing and (or) speed-dependent effects are discussed. From experimental data analysis, we conclude that lineshape models taking into account the Dicke effect only fail in the high pressure regime and lead to optical diffusion pa-rameters that are much larger than the kinetic diffusion ones. On the contrary, a fair interpretation of data is obtained fromspeed-dependent models, so that it is possible to derive a quantitative estimate of optical diffusion effects that appearmuch smaller than the kinetic diffusion ones. Xe-broadening coefficients of CO lines in the fundamental band at 297 and349 K are calculated from a semiclassical formalism involving successively two intermolecular potentials, the atom-atomLennard-Jones model, and a three-term expansion of Legendre polynomials with four adjustable parameters.

A silylated derivative of naphtho[1,2-c:5,6-c]difuran, 1,3,6,8-tetrakis(tert-butyldimethylsilyl)naphtho[1,2-c:5,6-c]difuran, has been isolated and its X-ray crystal structure determined. Bond localization confirms the polyene character of this isobenzofuran ring system. This molecule undergoes two successive Diels-Alder reactions with second-order rate constants differing by over 2 orders of magnitude, consistent with predictions based on their structure-count ratios and with the reactivity of the novel 1,3-bis(tert-butyldimethylsilyl)isobenzofuran. Crystal structures of two cyclophanes derived from the reaction of naphtho[1,2-c:5,6-c]difuran and bis(imide) or bis(ester) dienophiles show marked differences in the conformation of the aliphatic chain found in the solid state.

The title compound, C3H2Cl3N3, crystallizes as the Z isomer with respect to the C=N bond. The -C(NH2)=NCN functional group is effectively planar (r.m.s. deviation = 0.016 angstrom), with only the three Cl atoms out of the molecular plane. A strong network of N-H center dot center dot center dot N hydrogen bonds forms dimers which are associated into ribbons in the crystal structure. Hydrogen bonding is suspected to be the cause of the near-equivalence of the formal C-N and C=N bonds (Delta(CN) = 0.008 angstrom)

The structure of the title compound, 1,3-diphenyl-2-benzofuran, C20H14O, exhibits a distinct alternation of short [mean 1.361 (3) angstrom] and long [ mean 1.431 (3) angstrom] C-C bonds around the benzofuran ring system, indicating a predominantly polyene character. Over 60 Diels-Alder adducts of this commercially available furan have been structurally characterized, but this is the first report of the structure of the parent compound.

Sexually selected traits are thought to impose survival costs on showy males. Recent empirical work found a negative relationship between male display and survival in a field cricket species (Orthoptera, Gryllidae, Gryllinae) where there is no evidence of a mating bias toward older males. In most species, however, male survival and ornamentation are positively correlated, and older males often have a mating success advantage over younger males. These findings suggest that male quality and survival are positively correlated, but more tests of this hypothesis are needed. We measured the condition dependence of male survival and calling effort in another grylline, Gryllus pennsylvanicus, where older males have previously been shown to have greater mating success. We varied condition by manipulating diet, and measured male life span and calling effort to assess the relative condition dependence of these traits. High- and medium-condition males survived longer than low-condition males, and high-condition males called more than medium- and low-condition males. Differences in calling effort among the condition treatments were not apparent early in life, but emerged as males aged. We discuss possible explanations for the differences between our study and contrasting results such as the previous grylline work.

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The reaction of the 1,2,3,5-dithiadiazolyls (4-R-C6H4CN2S2)(2) (R = Me, 2a; Cl, 2b; OMe, 2c; and CF3, 2d) and (3-NC-5-(BU)-B-t-C6H3CN2S2)(2) (2e) with [CpCr(CO)(3)](2) (CP = eta(5)-C5H5) (1) at ambient temperature respectively yielded the complexes CpCr(CO)(2)(eta(2)-S2N2CC6H4R) (R = 4-Me, 3a; 4-Cl, 3b; 4-OMe, 3c; and 4-CF3, 3d) and CpCr(CO)(2)-(eta(2) -S2N2CC6H3-3-(CN)-5-(Bu-t)) (3e) in 35-72% yields. The complexes 3c and 3d were also synthesized via a salt metathesis method from the reaction of NaCpCr(CO)(3) (1B) and the 1,2,3,5-dithiadiazolium chlorides 4-R-C6H4-CN2S2Cl (R = OMe, 8c; CF3, 8d) with much lower yields of 6 and 20%, respectively. The complexes were characterized spectroscopically and also by single-crystal X-ray diffraction analysis. Cyclic voltammetry experiments were conducted on 3a-e, EPR spectra were obtained of one-electron-reduced forms of 3a-e, and variable temperature H-1 NMR studies were carried out on complex 3d. Hybrid DFT calculations were performed on the model system [CpCr(CO)(2)S2N2CH] and comparisons are made with the reported CpCr(CO)(2)(pi-allyl) complexes.

In the structure of the title compound, C16H14Br2, the central C=C bond length is 1.329 (4) angstrom and the two benzene rings are approximately coplanar with the double bond, with twist angles of 7.5 (2) and 13.6 (2)degrees.

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This book is comprised of two parts. The first usesdata on Canada to determine the role asset pricechanges should play in the conduct of monetary policywithin the inflation targeting and money growthtargeting frameworks. The findings indicate thatirrespective of the targeting framework, the policyrule that incorporates a response to asset pricechanges controls inflation better. Contrary to theconventional view, simulation experiments indicatethat the money growth targeting policy rule is moreefficient in controlling inflation than the inflationtargeting policy rule. The second part presents theoretical and conometricanalysis of the determinants of current accountbalances for Ghana. The results point to changes inworld real interest rate, exchange rate, and theterms of trade as important determinants of currentaccount. A policy regime analysis shows that therecent implementation of capital liberalizationpolicies in Ghana has enabled Ghanaians to use the international financial market to smooth consumption. The analysis should be useful to graduate students inbusiness schools and economic departments, and anyperson who is interested in international macroeconomic issues

We use the three potential description (3PD) to study the oscillatory dynamics of rotating stars. The 3PD scheme describes the exact  linearized dynamics of rotating, self-gravitating, stratified, compressible and inviscid fluids. We compute the frequencies and the displacement eigenfunctions for some of the inertial and gravity modes of polytropic  star models. The Coriolis force is the restoring force for the inertial modes while the gravity modes are induced by the buoyancy forces. We show that the frequencies of the inertial modes of these star models may be significantly different from those of a homogeneous and  incompressible model, an approximation usually made to compute the frequencies of the inertial modes of rapidly rotating stars. We will also investigate the effects of rotation on the frequencies of the gravity modes of these models. In order to test the validity and the accuracy of the  results from our approach, we compare the eigenfrequencies of some of the gravito-inertial modes of these models, computed using the 3PD, to those in the literature. 

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DFT calculations for the group 15 radicals [PhB(mu-(NBu)-Bu-t)(2)](2)M-center dot (M = P, As, Sb, Bi) predict a pnictogen-centered SOMO with smaller contributions to the unpaired spin density arising from the nitrogen and boron atoms. The reactions of Li-2[PhB(mu-NR)(2)] (R = Bu-t, Dipp) with PCl3 afforded the unsolvated complex LiP[PhB(mu-(NBu)-Bu-t)(2)](2) (1a) in low yield and CIP[PhB(mu-NDiPP)(2)] (2), both of which were structurally characterized. Efforts to produce the arsenic-centered neutral radical, [PhB(mu-(NBu)-Bu-t)(2)](2)As-center dot, via oxidation of LiAs[PhB(mu-(NBu)-Bu-t)(2)](2) with one-half equivalent of SO2Cl2, yielded the Zwitterionic compound [PhB(mu-(NBu)-Bu-t)(2)As(mu-(NBu)-Bu-t)(2)B(Cl)Ph] (3) containing one four-coordinate boron center with a B-Cl bond. The reaction of 3 with GaCl3 produced the ion-separated salt, [PhB(mu-(NBu)-Bu-t)(2)](2)As+GaCl4- (4), which was characterized by X-ray crystallography. The reduction of 3 with sodium naphthalenide occurred by a two-electron process to give the corresponding anion [{PhB(mu-(NBu)-Bu-t)(2)}(2)As](-) as the sodium salt. Voltammetric investigations of 4 and LiAs[PhB(mu-(NBu)-Bu-t)(2)](2) (1b) revealed irreversible processes. Attempts to generate the neutral radical [PhB(mu-(NBu)-Bu-t)(2)](2)As-center dot from these ionic complexes via in situ electrolysis did not produce an EPR-active species.

Carbon dioxide, water vapour, and energy fluxes vary spatially and temporally within forested environments. However, it is not clear to what extent they vary as a result of variability in the spatial distribution of biomass and elevation. The following study presents a new methodology for extracting changes in the structural characteristics of vegetation and elevation within footprint areas, for direct comparison with eddy covariance (EC) CO2 flux concentrations. The purpose was to determine whether within-site canopy structure and local elevation influenced CO2 fluxes in a mature jack pine (Pinus banksiana Lamb.) forest located in Saskatchewan, Canada. Airborne light detection and ranging (lidar) was used to extract tree height, canopy depth, foliage cover, and elevation within 30 min flux footprints. Within-footprint mean structural components and elevation were related to 30 min mean net ecosystem productivity (NEP) and gross ecosystem production (GEP). NEP and GEP were modeled using multiple regression, and when compared with measured fluxes, almost all periods showed improvements in the prediction of flux concentration when canopy structure and elevation were included. Increased biomass was related to increased NEP and GEP in June and August when the ecosystem was not limited by soil moisture. On a daily basis, fractional cover and elevation had varying but significant influences on CO2 fluxes.

Light-use efficiency (LUE) is the ability of vegetated canopies to use light for photosynthesis. Together with remote sensing estimates of canopy cover and meteorological inputs, LUE provides a physical basis for scaling carbon uptake processes from the stand to the global scale. A better understanding of the factors that control LUE will result in improved global estimates of carbon uptake from the terrestrial biosphere. To examine factors that control variability in LUE in stands of different ages during dry and wet conditions, we measured LUE in a chronosequence of four jack pine stands (recent clearcut (age 1–3), regenerating (age 8–9), immature (age 29–30) and mature (∼90 years old)) during one normal (2002), one very dry (2003) and two very wet (2004, 2005) growing seasons in Saskatchewan, Canada. Cumulative CO2 fluxes decreased significantly at all sites during the drought year of 2003, as did mean LUE. Canopy foliage at the recently regenerating jack pine site increased by 19% between 2002 and 2003. Foliage growth rate was reduced by 6% between 2003 and 2004, and foliage biomass decreased by 6% from 2004 to 2005. Over the four years studied, LUE was greatest at the mature jack pine site and lower, but similar, at the other three sites. Mean growing-season LUE varied with mean soil water content at each site, except at that of the newly regenerating stand where soil water had little influence. Mean daily vapor pressure deficit typically had the greatest influence on variability in LUE at all sites. Diffuse versus direct radiation also had significant but varying effects on LUE in jack pine stands of different ages.

Parental care is an energetically demanding activity that ensures genes are efficiently passed from one generation to the next. According to evolutionary theory, the greatest energetic investment should be directed towards offspring that are most closely related to the parent. Male fathead minnows, Pimephales promelas, provide this parental investment to developing embryos but not newly hatched larvae. Therefore, selection should favour recognition of embryonic kin to ensure energetic expenditure is optimally invested. In this study, adult male fathead minnows were tested using behavioural assays, with egg cannibalism as an endpoint, to determine whether adult males could discriminate between related and unrelated embryos. Egg cannibalism was highest when adult male fathead minnows were presented with unrelated eggs, and lowest when presented with eggs fertilized by the test subject (related eggs). The degree of cannibalism was also a function of breeding status. Unrelated males in breeding condition showed an intermediate response between the low cannibalism demonstrated by related males, and the high cannibalism demonstrated by unrelated males in a non-breeding condition. These results suggest that although male fathead minnows can discriminate between unrelated and related embryos, at least some component of parental investment is a simple function of breeding status.

The purpose of this study was to estimate the fraction of photosynthetically active radiation absorbed by the canopy (fPAR) from point measurements to airborne lidar for hierarchical scaling up and assessment of the Moderate Resolution Imaging Spectroradiometer (MODIS) fPAR product within a “medium-sized” (7 km × 18 km) watershed. Nine sites across Canada, containing one or more (of 11) distinct species types and age classes at varying stages of regeneration and seasonal phenology were examined using a combination of discrete pulse airborne scanning Light Detection And Ranging (lidar) and coincident analog and digital hemispherical photography (HP). Estimates of fPAR were first compared using three methods: PAR radiation sensors, HP, and airborne lidar. HP provided reasonable estimates of fPAR when compared with radiation sensors. A simplified fractional canopy cover ratio from lidar based on the number of within canopy returns to the total number of returns was then compared with fPAR estimated from HP at 486 geographically registered measurement locations. The return ratio fractional cover method from lidar compared well with HP-derived fPAR (coefficient of determination = 0.72, RMSE = 0.11), despite varying the lidar survey configurations, canopy structural characteristics, seasonal phenologies, and possible slight inaccuracies in location using handheld GPS at some sites. Lidar-derived fractional cover estimates of fPAR were ∼ 10% larger than those obtained using HP (after removing wood components), indicating that lidar likely provides a more realistic estimate of fPAR than HP when compared with radiation sensors. Finally, fPAR derived from lidar fractional cover was modelled at 1 m resolution and averaged over 99 1 km areas for comparison with MODIS fPAR. The following study is one of the first to scale between plot measurements and MODIS pixels using airborne lidar.

This review summarizes some of the main findings of our work with the Metals in the Environment Research Network examining seasonal and regional effects on metal accumulation, growth, condition, and physiology in wild yellow perch (Perca flavescens ) from 10 lakes comprising two metal contamination gradients in the indus- trial regions of Sudbury, Ontario and Rouyn-Noranda, Qu ´ ebec, Canada. The specific objectives of this review are: (1) to propose threshold tissue metal concentrations to discriminate between fish from contaminated and reference sites; (2) to identify factors that can influence metal accumulation and fish condition; and (3) to define an experimental approach for measuring metal effects in wild yellow perch. Using tissue thresholds appeared useful not only for discriminating fish from clean or con- taminated environments, but also provided a simple approach to examine metabolic consequences of tissue metal accumulation. Overall, fish from Sudbury grew faster, expressed higher aerobic capacities, and died younger, but also appeared better at limiting accumulation of some metals than Rouyn-Noranda fish. The condition of the latter fish was clearly more affected by metals than Sudbury fish. Finally, our dataset allows us to propose that yellow perch are highly suitable for ecological risk assessment studies of metal effects in wild fish, but that fish size, season, and re- gion must be considered in sampling design and that several reference sites must be studied for meaningful conclusions to be reached.

The remarkable group of Japanese Buddhists who traveled to Chicago's Columbian Exposition to participate in the 1893 World's Parliament of Religions combined religious aspirations with nationalist ambitions. Their portrayal of Buddhism mirrored modern reforms in Meiji, Japan, and the historical context of cultural competition on display at the 1893 World's Fair. Japan's primary exhibit, the Ho-o, or phoenix, Pavilion, provided an impressive display of traditional culture as well as apt symbolism: for Japan's modern rise to prominence, for Buddhist renewal succeeding devastating Meiji persecution, for Mahayana revitalization following withering attacks of Western critics, and for Chicago's own resurrection from the ashes of the Great Fire. This book examines the Japanese delegates' portrayal of Mahayana Buddhism as authentically ancient, pragmatically modern, scientifically consistent, and universally salvific. The Japanese delegates were active, and relatively successful agents who seized the opportunity of the 1893 forum to further their own objectives of promoting Japan and its Buddhism to the West, repairing negative evaluations of the «great vehicle» of Buddhism, differentiating Japanese Buddhism from the Buddhism of other countries, distinguishing their tradition as the evolutionary culmination of all religions, and shaping modern Buddhism in Asia and the West. «Conversations among representatives of the world's religions surely do not take place within a vacuum; the push and pull of global politics usually influences what gets said. So it is now and so it was as well in 1893 when some deeply concerned persons designed and attended the World's Parliament of Religions in Chicago. John S. Harding's account of Japan's Buddhist representation at that confab puts not only what was religious but also what was geo-political and even downright promotional into a fascinating narrative and very valuable analysis. Chicago was recovering from a terrible fire, Japan's Buddhists from criticisms at home, Japan as a whole from a period of self-isolation, and America from an image of being religiously parochial. A lot was at stake in 1893. This book deftly describes how these agendas converged during a unique, sometimes almost unimaginably bold meeting in mid-America in the late nineteenth century.» (William R. LaFleur, University of Pennsylvania)

Sexually selected male weaponry is widespread in nature. Despite being model systems for the study of male aggression in Western science and for cricket fights in Chinese culture, field crickets (Orthoptera, Gryllidae, Gryllinae) are not known to possess sexually dimorphic weaponry. In a wild population of the fall field cricket, Gryllus pennsylvanicus, we report sexual dimorphism in head size as well as the size of mouthparts, both of which are used when aggressive contests between males escalate to physical combat. Male G. pennsylvanicus have larger heads, maxillae and mandibles than females when controlling for pronotum length. We conducted two experiments to test the hypothesis that relatively larger weaponry conveys an advantage to males in aggressive contests. Pairs of males were selected for differences in head size and consequently were different in the size of maxillae and mandibles. In the first experiment, males were closely matched for body size (pronotum length), and in the second, they were matched for body mass. Males with proportionately larger weaponry won more fights and increasing differences in weaponry size between males increased the fighting success of the male with the larger weaponry. This was particularly true when contests escalated to grappling, the most intense level of aggression. However, neither contest duration nor intensity was related to weaponry size as predicted by models of contest settlement. These results are the first evidence that the size of the head capsule and mouthparts are under positive selection via male-male competition in field crickets, and validate 800-year-old Chinese traditional knowledge

Recent evidence suggests that offspring viability is related to maternal characteristics in fishes, possibly because ova quality is dependent upon these maternal traits. Provisioning of ova with particular constituents may vary with the age, size, and current condition of the female. We examined patterns of within- and among-population variation in ova concentrations of seven essential metals (Ca, Co, Cu, Fe, Mg, Mn, Zn) in four walleye (Sander vitreus) and one lake whitefish (Coregonus clupeaformis) populations. Within populations, among-female variability in ova metal concentrations was lowest for Zn (CVs 6.2-11%), and highest for Mn (CVs 26-88%). However, ova metal concentrations were not consistently related to maternal age, size, or indices of body condition. Mean ova metal concentrations varied significantly among walleye populations for five of the seven metals examined; variability was lowest for Ca and Co, and highest for Mg and Mn. Walleye and lake whitefish from the same waterbody, Lake Ontario, also differed significantly in ova metal concentrations. Lake whitefish produced ova with significantly higher concentrations of Ca, Fe, Mn, and Zn. Ova metal concentrations observed in this study were generally lower than those reported in earlier studies. Metal provisioning of ova in walleye and lake whitefish does not appear to be related to the ontogenetic or nutritional state of the female.

We report measurements for N2-broadening, pressure-shift and line mixing coefficients for 55 oxygen transitions in the A-bandretrieved using a multispectrum fitting technique. Nineteen laboratory absorption spectra were recorded at 0.02 cm1 resolution usinga multi-pass absorption cell with path length of 1636.9 cm and the IFS 120 Fourier transform spectrometer located at Justus-Liebig-Uni-versity in Giessen, Germany. The total sample pressures ranged from 8.8 to 3004.5 Torr with oxygen volume mixing ratios in nitrogenranging between 0.057 and 0.62. An Exponential Power Gap (EPG) scaling law was used to calculate the N2-broadening and N2-linemixing coefficients.The line broadening and shift coefficients for the A-band of oxygen self-perturbed and perturbed by N2 are modeled using semiclas-sical calculations based on the Robert–Bonamy formalism and two intermolecular potentials. These potentials involve electrostatic con-tributions including the hexadecapole moment of the molecules and (a) a simple dispersion contribution with one adjustable parameter tofit the broadening coefficients or (b) the atom–atom Lennard-Jones model without such adjustable parameters. The first potential leadsto very weak broadening coefficients for high J transitions whereas the second potential gives much more improved results at mediumand large J values, in reasonable agreement with the experimental data. For the line shifts which mainly arise in our calculation from theelectronic state dependence of the isotropic potential, their general trends with increasing J values can be well predicted, especially fromthe first potential. From the theoretical results, we have derived air-broadening and air-induced shift coefficients with an agreement com-parable to that obtained for O2–O2 and O2–N2. 2008 Elsevier Inc. All rights reserved.

The antipredator responses of adult and larval fathead minnows Pimephales promelas to chemical alarm cues prepared throughout ontogeny were tested using various behavioural assays. Larval epidermis was also examined during ontogeny using standard haematoxylin and eosin staining techniques. Adults elicited an antipredator response to chemical alarm cue made from larvae as young as 8201317 days post-hatch. Interestingly, larvae did not possess visible club cells until 28201337 days post-hatch and did not respond to conspecific chemical alarm cue until 48201357 days post-hatch. These results suggest that chemical alarm cue may not be contained within club cells and that the components of larval and adult chemical alarm cue may be similar throughout ontogeny.

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The title phosphine, Dipp(3)P, was synthesized using an aryl copper reagent and the structure determined by X-ray crystallography (R=2.94%): d(P - C)=1.852(1) angstrom, angle C - P - C=111.88(5)degrees. In hexane solution, the electronic spectrum displays 3 bands [326 (9.3), 254 (8.7), 205 (11.4) nm (log|epsilon|)] and the fluorescence spectrum has a Stokes shift of 129 kJ mol(-1). NMR: ( d) P-31= - 49.7 ppm in solution and - 49.5 in the solid (CP-MAS). Room temperature 1 H and 13 C spectra reflect D-3 symmetry, changing below - 30 degrees C to C-3. A variable temperature NMR study provided an activation enthalpy of 49(+/- 1) kJ mol(-1) and entropy of 24 - 27(+/- 5) J mol(-1) K-1. An energy surface calculation using HF/3-21G theory discovered a single low-energy path describing pyramidal inversion through a transition state that is close to D3 geometry. The B3LYP/6-31G(d) calculated barrier to planarization is 37.5 kJ mol(-1). Voltammetric studies employing cyclic, rotating disk, steady state and Fourier Transform ac methods confirm a fully chemically reversible one-electron oxidation of Dipp(3)P to Dipp(3)P(+center dot) at +0.18 (CH3CN - (Bu4NPF6)-Bu-n) and +0.09 (CH2Cl2 - (Bu4NPF6)-Bu-n) V vs. Fc(+/0) (Fc=ferrocene). The diffusion coefficient for Dipp(3)P is 1.0 - 1.2 x 10(5) cm(2) s(-1). The electrode process displays quasi-reversible electron transfer kinetics [k(s)approximate to 0.01 (CH2Cl2) to 0.08 (CH3CN) cm s(-1)]. Optically transparent thin layer electrolysis reversibly generates Dipp(3)P(+center dot) in CH2Cl2 - (Bu4NPF6)-Bu-n [UV- Vis: 498 (3.31), 456 (3.29), 373 (4.04), 357 (3.84), 341 (3.49), 296 (3.78), 385 (3.91), 251 (3.99) nm (log|epsilon|)]. The EPR spectrum of Dipp(3)P(+center dot) in solution is a doublet (a(P)=23.9 mT, g=2.008), and in frozen solution is axial (a(parallel to)=42.6 mT, g(parallel to)=2.0045; a(perpendicular to)=12.7 mT, g(perpendicular to)=2.0085 mT).

Rainbow trout (Oncorhynchus mykiss) are often used to estimate important biotic ligand model (BLM) parameters, such as metal-binding affinity (log K) and capacity (Bmax).  However, rainbow trout do not typically occupy metal-contaminated environments, whereas yellow perch (Perca flavescens) are ubiquitous throughout most of North America.  This study demonstrates that dynamic processes that regulate Cu uptake at the gill differ between rainbow trout and yellow perch.  Rainbow trout were more sensitive to acute aqueous Cu than yellow perch, and toxicity was exacerbated in soft water relative to similar exposures in hard water.  Whole body Na loss rate could account for acute Cu toxicity in both species, as opposed to new Cu uptake rate which was not as predictive.  Time course experiments using radiolabelled Cu (64Cu) revealed that branchial Cu uptake was rather variable within the first 12 h of exposure, and appeared to be a function of Cu concentration, water hardness, and fish species.  After 12 h, new branchial Cu concentrations stabilized in both species, suggesting that metal exposures used to estimate BLM parameters should be increased in duration from 3 h to 12+ h. In rainbow trout, 71% of the new Cu bound to the gill was exchangeable (i.e., able to either enter the fish or be released back to the water), as opposed to only 48% in yellow perch.  This suggests that at equal exposure concentrations, proportionally more branchial Cu can be taken up by rainbow trout than yellow perch, which can then go on to confer toxicity.  These qualitative differences in branchial Cu handling between the two species emphasize the need to develop BLM parameters for each species of interest, rather than the current practice of extrapolating BLM results derived from rainbow trout (or other laboratory-reared species) to other species.  Data reported here indicate that a one-size-fits-all approach to predictive modeling, mostly based on rainbow trout studies, may not suffice for making predictions about metal toxicity to yellow perch—i.e., a species that inhabits metal-contaminated lakes around northern Canadian industrial operations.

Maternal size influenced egg fatty acid profiles in Lake Ontario walleye but not in those from Lake Winni- peg. Maternal somatic parameters had few predictive influences on egg metal concentrations and these were not consistent between the populations.

This study examined relationships among water, sediment, diet and fish tissue metal (Cd, Cu, Ni, Se and Zn) concentrations in yellow perch from metal gradients in two regions (Sudbury (S), Ontario and Rouyn-Noranda (RN), QuÈbec Canada) in two seasons (spring and summer). The objectives of this study were (i) to examine the influences of aqueous and dietary metal contamination on yellow perch liver and kidney metal accumulation; (ii) to compare the seasonal and regional variations in gut content and tissue metal concentrations along the two gradients studied; and (iii) to investigate the potential of metals for tissue accumulation under conditions of life-long chronic exposure. Contaminated RN lakes were characterized by elevated concentrations of Cd, Cu and Zn in water and sediment, while contaminated Sudbury lakes were characterized by elevated concentrations of Cd, Cu and Ni in water, and Cu and Ni in sediment. Dietary metal contamination largely reflected water and sediment contamination for Cd and Cu and to a lesser extent for Ni and Zn, but not for Se. Liver and kidney concentrations of Cd and Cu, and to a lesser extent Ni, Se and Zn, also correlated with dietary contamination, indicating that both aqueous and dietary sources are significant contributors for these metals. Dietary metal concentrations often decreased, but never increased, with size, suggesting that metal exposure through diet generally decreases in larger yellow perch. Although Cd accumulated in the tissues of older fish from some lakes in the RN region, overall, metals did not accumulate with age in liver or kidney of fish from either region. Seasonal variations in tissue metal concentrations were inconsistent between regions, and sometimes also between tissues. Our data suggests that S fish, having been historically exposed to high concentrations of Cu and Ni, may have evolved better capacities for the regulation of tissue concentrations of these metals compared to RN fish. Finally, of all the metals examined, Zn appeared to be the most regulated, and Cd the least. This data clearly highlights the importance of repeated sampling for assessing effects of metal contaminants in wild fish, and further suggests that yellow perch from Sudbury may have adapted to metal exposure.

Wild yellow perch (Perca flavescens) were sampled from five lakes in each of two metal contamination gradients in Sudbury, ON (n = 1324) and Rouyn-Noranda, QC (n = 1125) in the spring and summer of 2002 and 2003, respectively, in order to examine growth patterns, longevity, and the single and combined influences of season, region, and position along each metal contamination gradient on fish condition. Growth patterns varied by contamination gradient; fish from Rouyn-Noranda began rapid growth at a young age, whereas fish from Sudbury lakes showed slow growth rates between ages 0-3, after which growth rates improved. Slopes of double-log plots of fish weight and lengths varied between the two study regions when all fish were considered together and when the analysis was restricted only to non-contaminated reference lakes. Fish from contaminated lakes grew faster and died younger than fish from reference lakes in both contamination gradients. Observed growth patterns are likely due to increased food consumption in metal-contaminated lakes, as a compensatory means of replacing lost electrolytes from chronic metal exposure. Fish from Sudbury had lower condition than those from Rouyn-Noranda, higher condition occurred in the summer than in the spring, and fish from contaminated lakes had lower condition than those from cleaner lakes. However, when condition was studied at the level of individual lakes within each contamination gradient, condition variability was too high to draw any meaningful conclusions. Tissue Zn accumulation appeared to correlate with fish condition. However, tissue Zn concentrations demonstrate strong temporal stability, and it is more likely that Zn covariates, such as Cd or Cu (both of which are much less temporally stable in fish tissues) actually influenced condition. These results suggest that long-term processes are more important than short-term processes for establishing growth patterns, longevity, and fish condition in metal-contaminated systems.

The influences of metal contamination, fish size, season, and region on tissue metabolic capacities and protein concentrations were examined in yellow perch from two metal gradients (Sudbury, Ontario, and Rouyn-Noranda, Qu ´ ebec, Canada) in two seasons (spring and summer). In general, increased tissue Cu and Cd contamination was associated with lower aerobic capacities, suggesting direct metal inhibition of aerobic enzymes. However, our data also revealed that tissue Ni contamination positively affected aerobic capacities, possibly due to oxidative damage to mitochon- drial membranes leading to compensatory increases in the activity of mitochondrial enzymes. Tissue aerobic capacities decreased, but anaerobic capacities increased, with size. Tissue protein concentrations and metabolic capacities were also influ- enced by season. A novel finding of this study is that size-corrected tissue enzyme activities can differ markedly in yellow perch sampled in the same season in similar lakes, but separated by a few hundred kilometers. Overall, the results from this large dataset support that tissue metabolic capacities are under seasonal and regional influences, but are also affected by metal contamination. Our study indicates that tissue metabolic enzyme activities should be considered as a tool for ecological risk assessment studies aiming at detecting metal stress in wild fish. However, fish should be sampled over a short period, and reference sites should be close to contaminated sites.

Scientific literature often touts the many advantages of large body size, but seldom addresses the value of small body size. Yet selection for large size must be counterbalanced by selection for small size, otherwise, all animals would be large. In this paper, we demonstrate female-biased size dimorphism and a strong copulatory advantage for small males in a Jerusalem cricket (JC) (Stenopelmatus) from central California. We selectively paired male and female JCs of diverse body sizes and recorded their ability to copulate. All copulations were successful for males smaller or equal in size to females. In contrast, when the male was 6.1 mm longer than the female, copulation had only a 50% chance of occurring successfully. In general, as the difference between male and female body length increased (i.e., as males became longer than their mates), the probability of successful copulation decreased. These patterns of mating resulted in net selection for small male size and large female size. We also detected positive linear direct selection on male hind leg length, which may explain why male JCs have longer legs than females. The copulatory disadvantage of large males derives from the odd mating behavior of this group, in which males must contort and precisely align their bodies to couple. We believe that this is the first example of small-male advantage based solely on the physical aspects of copulation. In this species, small, not large, males have a copulatory advantage. 

This paper reports accurate line positions, intensities, self-broadening, -shift and -line mixing coefficients for 56 rotational transitionsfrom multispectrum fits of low noise, high-resolution Fourier-transform spectra. The measured line intensities are within the statisticalspread of the previous measurements available in the literature—thus contributing to the efforts to measure the oxygen A-band intensitieswith an accuracy better than 1%. We determined the integrated band strength and Einstein A coefficient. Using our spectrum calibrationmethod we could clearly show for the first time that there is a meaningful statistical discrepancy in the frequency standards used in spec-troscopic studies for the oxygen A-band. We were able to explain how this discrepancy leads to two different sets of shifts reported in theliterature and demonstrate the need for precise frequency-type transition wavenumber measurements of the oxygen A-band transitions.We observed deviations from the conventional Voigt profile due to speed-dependent broadening and line mixing effects. Dicke narrowingwas observed on a selected group of spectra recorded at pressures between 98 and 337 Torr. The Dicke narrowed lineshapes were bestmodeled using a Galatry profile implemented using a fixed value for the velocity-changing collision rate. The weak line mixing coefficientswere determined from fits using the speed-dependent models. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scal-ing laws were used to calculate the self-broadening and self-line mixing coefficients. 2007 Elsevier Inc. All rights reserved.

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A straightforward and efficient synthetic route to thiazolyl phosphines is reported. Moreover, the first application of these molecules in catalysis is described. These phosphines are excellent ligands in the copper-catalyzed arylation and vinylation of nucleophiles. The reactions could be performed in acetonitrile and various mixed aqueous/organic solvents and even in pure water in the presence of a phase transfer catalyst. In each case, coupling products are obtained with high yields at very mild temperatures.

We propose a causal relationship between the creation of the giant impact basins on Mars by a large asteroid, ruptured when it entered the Roche limit, and the excitation of the Martian core dynamo. Our laboratory experiments indicate that the elliptical instability of the Martian core can be excited if the asteroid continually exerts tidal forces on Mars for ~20,000 years. Our numerical experiments suggest that the growth-time of the instability was 5,000–15,000 years when the asteroid was at a distance of 50,000–75,000 km. We demonstrate the stability of the orbital motion of an asteroid captured by Mars at a distance of 100,000 km in the presence of the Sun and Jupiter. We also present our results for the tidal interaction of the asteroid with Mars. An asteroidcaptured by Mars in prograde fashion can survive and excite the elliptical instability of the core for only a few million years, whereas a captured retrograde asteroid can excite the elliptical instability for hundreds of millions of years before colliding with Mars. The rate at which tidal energy dissipates in Mars during this period is over two orders of magnitude greater than the rate at which magnetic energy dissipates. If only 1% of the tidal energy dissipation is partitioned to the core, sufficient energy would be available to maintain the core dynamo. Accordingly, a retrograde asteroid is quite capable of exciting an elliptical instability in the Martian core, thus providing a candidate process todrive a core dynamo. 

Branchial binding kinetics and gastro-intestinal uptake of copper and cadmium where examined in yellow perch (Perca flavescens) from a metal-contaminated lake (Hannah Lake, Sudbury, Ontario, Canada) and an uncontaminated lake (James Lake, North Bay, Ontario, Canada). An in vivo approach was taken for gill binding comparisons while an in vitro gut binding assay was employed for gastro-intestinal tract (GIT) uptake analysis. By investigating metal uptake at the gill and the gut we cover the two main routes of metal entry into fish. Comparisons of water and sediment chemistries, metal burdens in benthic invertebrate, and metal burdens in the livers of perch from the two study lakes clearly show that yellow perch from Hannah L. are chronically exposed to a highly metal-contaminated environment compared to a reference lake. We found that metal-contaminated yellow perch showed no significant difference in gill Cd binding compared to reference fish, but they did show significant decreases in new Cd binding and absorption in their GITs. The results show that gill Cd binding may involve low-capacity, high-affinity binding sites, while gastro-intestinal Cd uptake involves binding sites that are high-capacity, low-affinity. From this we infer that Cd may be more critically controlled at the gut rather than gills. Significant differences in branchial Cu binding (increased binding) were observed in metal-contaminated yellow perch. We suggest that chronic waterborne exposure to Cu (and/or other metals) may be the dominant influence in gill Cu binding rather than chronic exposure to high Cu diets. We give supporting evidence that Cd is taken up in the GIT, at least in part, by a similar pathway as Ca(2+), principally that elevated dietary Ca(2+) reduces Cd binding and uptake. Overall our study reveals that metal pre-exposure via water and diet can alter uptake kinetics of Cu and Cd at the gill and/or the gut.

Zinc is an essential micronutrient for freshwater fish but can be toxic to them at elevated concentrations. Therefore, the regulation of zinc uptake is important in maintaining homeostasis when fish are chronically exposed to elevated zinc in nature. This study examined the kinetics of in vivo branchial and in vitro intestinal zinc uptake in wild yellow perch (Perca flavescens) from metal-contaminated and reference lakes in northern Ontario. The results showed that the branchial zinc uptake involves high affinity transport sites whereas the intestinal zinc uptake involves low affinity transport sites. Interestingly, significant alterations in the branchial zinc uptake (reduced affinity, increased maximum transport rate) but no apparent changes in the intestinal zinc uptake characteristics were observed in the metal-impacted yellow perch population relative to the reference population. Subsequently, no differences in zinc concentrations of gill, liver and whole body were recorded between reference and metal-impacted yellow perch populations. Overall, our study indicated that the gill, not the gut, likely plays a critical role in maintaining the zinc homeostasis in wild fish under chronic exposure.

The combined use of theoretical and mathematical methods in the analysis of electron paramagnetic resonance data has greatly increased the ability to interpret even the most complex spectra reported for doublet state inorganic main group radicals. This personal account summarizes the theoretical basis of such an approach and provides an in-depth discussion of some recent illustrative examples of the utilization of this methodology in practical applications. The emphasis is on displaying the enormous potential embodied within the approach. (c) 2006 Elsevier B.V. All rights reserved.

DOI: 10.1080/10807030701340995 Gregory G. Pyle a &amp; Reehan S. Mirzaa pages 492-505. Available online: 11 May 2007. ...

The title compound, C5H12N+center dot Cl-, contains [Et2N = CH2](+) and Cl- ions. The C = N double-bond distance is 1.2729 (13) angstrom and the sum of the angles around the central N atom is 359.92 degrees. There are short contacts [2.973 (1) angstrom] between the iminium C atom and the Cl- ion and between five of the C-H H atoms and the Cl- ion, of which the shortest is 2.623 (11) angstrom.

The highly reactive palladium-centered radical cluster [Pd-3(dpPM)(3)(CO)](center dot+) exhibits only a limited stability in solution at room temperature (about an hour). This stability can be extended significantly to several hours by adding organic substrates such as the symmetric and asymmetric alkynes Ph-C C-H and MeO2C-C C-CO2Me, which reversibly bind to the Pd-3 triangle. The presence of the substrate inside the cavity protects the palladium centers from reacting with the "outside world", hence enhancing the stability. Both adducts are stable as the cluster is always totally recovered. The paramagnetic complexes along with their corresponding dications were characterized by EPR, variable-temperature P-31 NMR, UV-vis and MALDI-TOF spectroscopy, and electrochemistry. For the MeO2C-C C-CO2Me/[Pd-3-(dppm)(3)(CO)](2+) complex, the analysis of the low-temperature P-31 NMR spectra strongly suggests a major structure modification of the ligand and substrate with respect to the starting materials.

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The previously unknown radical anions of unsaturated E2N4S2 ring systems (E = RC, R2NC, R2P) can be generated voltammetrically by the one-electron reduction of the neutral species and, despite half-lives on the order of a few seconds, have been unambiguously characterized by electron paramagnetic resonance (EPR) spectroelectrochemistry using a highly sensitive in situ electrolysis cell. Cyclic voltammetric studies using a glassy-carbon working electrode in CH3CN and CH2Cl2 with [(Bu4N)-Bu-n][PF6] as the supporting electrolyte gave reversible formal potentials for the [E2N4S2](0/-) process in the range of -1.25 to -1.77 V and irreversible peak potentials for oxidation in the range of 0.66 to 1.60 V (vs the Fc(+/0) couple; Fc = ferrocene). Reduction of the neutral compound undergoes an electrochemically reversible one-electron transfer, followed by the decay of the anion to an unknown species via a first-order (chemical) reaction pathway. The values of the first-order rate constant, k(f), for the decay of all the radical anions in CH2Cl2 have been estimated from the decay of the EPR signals for (X-C6H4CN2S)(2)(center dot-), where X = 4-OCH3 (k(f) = 0.04 s(-1)), 4-CH3 (k(f) = 0.02 s(-1)), 4-H (k(f) = 0.08 s(-1)), 4-Cl (k(f) = 0.05 s(-1)), 4-CF3 (k(f) = 0.05 s(-1)), or 3-CF3 (k(f) = 0.07 s(-1)), and for [(CH3)(3)CCN2S](2)(center dot-) (k(f) = 0.02 s(-1)), [(CH3)(2)NCN2S](2)(center dot-) (k(f) = 0.05 s(-1)), and [(C6H5)(2)PN2S](2)(center dot-) (k(f) = 0.7 s(-1)). Values of k(f) for X = 4-H and for [(CH3)(2)NCN2S](2)(center dot-) were also determined from the cyclic voltammetric responses (in CH2Cl2) and were both found to be 0.05 s(-1). Possible pathways for the first-order anion decomposition that are consistent with the experimental observations are discussed. Density functional theory calculations at the UB3LYP/6-31G(d) level of theory predict the structures of the radical anions as either planar (D-2h) or folded (C-2v) species; the calculated hyperfine coupling constants are in excellent agreement with experimental results. Linear correlations were observed between the voltammetrically determined potentials and both the orbital energies and Hammett coefficients for the neutral aryl-substituted rings.

Computational methods are used to investigate the effects of fluid ompressibility on the frequencies of the inertial modes of the Earth’s fluid core. The 3PD (the three potential description) is applied to two models of compressible fluid spheres, for one of which the dilatation vanishes, in order to study these modes. We show that compressibility may have a significant effect on some of the modal frequencies. Using the shape of the displacement eigenfunctions of a fluid sphere we also infer which modes of a sphere may have counterparts in a spherical shell. We then give a few examples of the inertial modes of a compressible fluid shell proportional to the Earth’s fluid core.

This study provides the first direct experimental measurements of the off-diagonal relaxation matrix element coefficients for line mixingin air-broadened methane spectra for any vibrational band and the first off diagonal relaxation matrix elements associated with line mix-ing for pure methane in the m2 + m3 band of 12CH4. The speed-dependent Voigt profile with line mixing is used with a multispectrumnonlinear least squares curve fitting technique to retrieve the various line parameters from 11 self-broadened and 10 air-broadened spec-tra simultaneously. The room temperature spectra analyzed in this work are recorded at 0.011 cm1 resolution with the McMath-PierceFourier transform spectrometer located at the National Solar Observatory, Kitt Peak, Arizona. The off-diagonal relaxation matrix ele-ment coefficients of m2 + m3 transitions between 4410 and 4629 cm1 are reported for eighteen pairs with upper state J values between 2and 11. The observed line mixing coefficients for self broadening vary from 0.0019 to 0.0390 cm1 atm1 at 296 K. The measured linemixing coefficients for air broadening vary from 0.0005 to 0.0205 cm1 atm1 at 296 K. 2007 Elsevier Inc. All rights reserved.

In this work we present a line profile study for air-broadened carbon dioxide transitions in the 30012‹00001 and 30013‹00001vibrational bands. The room temperature spectra were recorded at a resolution of 0.008 cm1 using a Fourier Transform spectrometer.The air-broadening, air-shift, and air-line mixing coefficients were derived from a simultaneous fitting of spectra using the Voigt modeland a Speed-Dependent Voigt lineshape model. The results obtained are consistent with other studies in addition to the theoreticallycalculated values. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws were used to calculate the relaxationmatrix elements.

Transitions of pure carbon dioxide have been measured using a Fourier transform spectrometer in the 30012‹00001 and30013‹00001 vibrational bands. The room temperature spectra, recorded at a resolution of 0.008 cm1, were analyzed using the Voigtmodel and a Speed Dependent Voigt line shape model that includes a pressure dependent narrowing parameter. Intensities, self-inducedpressure broadening, shifts, and weak line mixing coefficients are determined. The results obtained are consistent with other studies inaddition to the theoretically calculated values. Exponential Power Gap (EPG) and Energy Corrected Sudden (ECS) scaling laws wereused to calculate the relaxation matrix elements. 2007 Elsevier Inc. All rights reserved.

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The scattered electron paramagnetic resonance (EPR) spectroscopic data for binary sulfur-nitrogen (S,N) radicals have been compiled and critically assessed. Many of these are inorganic rings or cages. For each species, possible equilibrium structures in the gas phase and the EPR hyperfine coupling (hfc) constants have been calculated with DFT using the B3LYP functional and basis sets of triple-zeta (or better) quality. Good agreement is obtained between calculated and measured values for the well characterized [S(3)N(2)](+), a planar pi-radical for which the s-component of the orbitals is likely to be reasonably independent of minor geometrical changes between gas-phase and condensed-phase states. The cage compounds [S(4)N(4)](-.) and [S(4)N(5)](-2), for which reliable experimental EPR spectra have been reported, show larger variation between calculated and measured hfc, as a consequence of the dependence of the s orbital content of the molecular orbitals on small structural changes. The very large disagreements between the DFT calculated and experimentally claimed hfc constants for [NS](-), [SNS](-) and [S(4)N(4)](-3), in condensed phases lead us to question their assignment. Among binary S,N radicals, (33)S hfc data has only been reported for [S(3)N(2)](+.) (through isotopic enrichment). These values were essential for the correct identification of the EPR spectra of this important radical, which previously was misassigned to other species. Our results suggest that (33)S data will be equally important for the correct identification of the EPR spectra of other binary S,N species, many of which are cyclic systems, e.g. [S(3)N(3)](.), [S(4)N(3)](.) and [S(4)N(5)]. (c) 2006 Elsevier B.V. All rights reserved.

The 2:1 adduct of benzyne with 2-methylanisole is shown to have the bisbenzotricyclic structure 6,6a,11,11a-tetrahydro-5-methoxy-6-methyl-5,6,11-metheno-5H-benzo[a]fluorene by a single-crystal X-ray diffraction study (C20H18O: Pca2(1), a = 15.0497(17), b = 9.87783(11), c = 9.6846(11); Z = 4; 1672 data points, R, = 0.0325). This structure is compared to an unpublished crystal structure of the parent hydrocarbon 6,6a, 11, 11a-tetrahydro-5,6,11-metheno-5H-benzo[a]fluorene, C18H14. Both structures have also been computed by DFT methods at the B3LYP/6-311 (d,p) level of theory. Bond distances and angles between the solid-state measurements and gas-phase calculations are found to agree well; average deviations are well below 1%. The H-1 NMR spectra show surprisingly small (3)J(HH) couplings in the central tricyclic cage, but can be assigned using 2D spectroscopy.

A rational synthesis for 5-tert-butyl-3-cyano-1-(1,2,3,5-dithiadiazolyl) benzene; which was first observed from thermal cleavage of the bis-dithiadiazolyl, has been developed. Voltammetry and electron paramagnetic resonance (EPR) spectra for this radical are reported and its X-ray structure is described. Despite the bulky Bu-t substituent, the cyano supramolecular synthon is still able to maintain links to a single neighbouring sulfur atom of the S-2 unit, as previously observed in cyano-substituted dithiadiazolyls. In the eta(2) complex with CpCr(CO)(2), no such interactions are observed; the nitrile group forms a centrosymmetric dimer through weak contacts with the para H atom on the aryl ring of the partner molecule. This behaviour is contrasted to similar complexes of less bulky dithiadiazolyls, where intermolecular interactions are retained in the crystalline lattice. (c) 2006 Elsevier B.V. All rights reserved.

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Stable and persistent phosphorus-containing radicals can be divided into five general categories: phosphinyl, diphosphanyl, 1,3-diphosphaallyl, lithiated tetrakisimidophosphates, and phosphaverdazyl systems. The syntheses, structures, EPR spectroscopic characterization, and sources of stability of these neutral radicals are presented and compared.

The prefrontal cortex and basal ganglia are deeply implicated in working memory. Both structures are subject to dopaminergic neuromodulation in a way that exerts a critical influence on the proper operation of working memory. We present a novel network model to elucidate the role of phasic dopamine in the interaction of these two structures in initiating and maintaining mnemonic activity. We argue that neuromodulation plays a critical role in protecting memories against both internal and external sources of noise. Increases in cortical gain engendered by prefrontal dopamine release help make memories robust against external distraction, but do not offer protection against internal noise accompanying recurrent cortical activity. Rather, the output of the basal ganglia provides the gating function of stabilization against noise and distraction by enhancing select memories through targeted disinhibition of cortex. Dopamine in the basal ganglia effectively locks this gate by influencing the stability of up and down states in the striatum. Dopamine's involvement in affective processing endows this gating with specificity to motivational salience. We model a spatial working memory task and show that these combined effects of dopamine lead to superior performance.

The oscillatory dynamics of a rotating, self-gravitating, stratified, compressible, inviscid fluid body is simplified by an exact description in terms of three scalar fields which are constructed from the dilatation, and the perturbations in pressure and gravitational potential [Seyed-Mahmoud, B., 1994.Wobble/nutation of a rotating ellipsoidal Earth with liquid core: implementation of a new set of equations describing dynamics of rotating fluids M.Sc. Thesis, Memorial  University of Newfoundland]. We test the method by applying it to compressible, but neutrally-stratified, models of the Earth’s liquid core, including a solid inner core, and compute the frequencies of some of the inertial modes. We conclude the method should be further exploited for astrophysical and geophysical normal mode computations.

The title heterocyclic radicals coordinate to either 17e CpCr(CO)(3) or 15e CpCr(CO)(2) moieties as one-electron or as three-electron donors, respectively; in the former the bonding is via the perpendicular p orbital of the sulfur atom, while in the latter bonding is via p(pi) orbitals on both sulfur and nitrogen.

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In this paper, we report measured Lorentz N2-broadening and N2-induced pressure-shift coefficients of CH3D in the m2 fundamentalband using a multispectrum fitting technique. These measurements were made by analyzing 11 laboratory absorption spectra recorded at0.0056 cm1 resolution using the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory on KittPeak, Arizona. The spectra were obtained using two absorption cells with path lengths of 10.2 and 25 cm. The total sample pressuresranged from 0.98 to 402.25 Torr with CH3D volume mixing ratios of 0.01 in nitrogen. We have been able to determine the N2 pres-sure-broadening coefficients of 368 m2 transitions with quantum numbers as high as J00 = 20 and K = 16, where K00 = K0 ” K (for a parallelband). The measured N2-broadening coefficients range from 0.0248 to 0.0742 cm1 atm1 at 296 K. All the measured pressure-shifts arenegative. The reported N2-induced pressure-shift coefficients vary from about 0.0003 to 0.0094 cm1 atm1. We have examined thedependence of the measured broadening and shift parameters on the J00, and K quantum numbers and also developed empirical expres-sions to describe the broadening coefficients in terms of m (m = J00, J00, and J00 + 1 in the QP-, QQ-, and QR-branch, respectively) and K.On average, the empirical expressions reproduce the measured broadening coefficients to within 4.7%. The N2-broadening and pressure-shift coefficients were calculated on the basis of a semiclassical model of interacting linear molecules performed by considering in addi-tion to the electrostatic contributions the atom–atom Lennard-Jones potential. The theoretical results of the broadening coefficients arein good overall agreement with the experimental data (8.7%). The N2-pressure shifts whose vibrational contribution is derived fromparameters fitted in the QQ-branch of self-induced shifts of CH3D, are also in reasonable agreement with the scattered experimental data(20% in most cases). 2005 Elsevier Inc. All rights reserved.

Room temperature Lorentz air-broadened halfwidth and pressure-induced air-shift coefficients were measured for 1011 transitions inthe octad region of methane between 4100 and 4635 cm1. These measurements were made by analyzing 10 laboratory absorption spec-tra recorded at 0.011 cm1 resolution using the McMath–Pierce Fourier transform spectrometer located at the National Solar Observa-tory on Kitt Peak, Arizona. The spectra were obtained using two absorption cells with path lengths of 2.05 and 150 cm. The total samplepressures ranged from 99 to 400 torr with CH4 volume mixing ratios of 0.01 in dry air. The spectral line parameters were retrieved using amultispectrum nonlinear least squares technique. Transitions belonging to five bands of the octad polyad were observed, namely m2 +2m4,m1 + m4, m3 + m4,2m2 + m4, and m2 + m3. The numbers of measurements by bands are: 33 for m2 +2m4, 180 for m1 + m4, 635 for m3 + m4, 33 for2m2 + m4, and 130 for m2 + m3. Transitions with rotational quantum number J up to 16 are included in the analysis. The measured widthand shift coefficients vary according to the tetrahedral symmetry species and the rotational quantum numbers of the transitions. Theretrieved parameters from this study are compared with prior results, in part to estimate absolute accuracy and determine the extentof vibrational dependence of widths and shifts. 2006 Elsevier Inc. All rights reserved.

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We report measured Lorentz O2-broadening and O2-induced pressure-shift coefficients of CH3D in the m2 fundamental band. Using amultispectrum fitting technique we have analyzed 11 laboratory absorption spectra recorded at 0.011 cm 1 resolution using theMcMath–Pierce Fourier transform spectrometer, Kitt Peak, Arizona. Two absorption cells with path lengths of 10.2 and 25 cm wereused to record the spectra. The total sample pressures ranged from 0.98 to 339.85 Torr with CH3D volume mixing ratios of 0.012 inoxygen. We report measurements for O2 pressure-broadening coefficients of 320 m2 transitions with quantum numbers as high asJ00 = 17 and K = 14, where K00 = K0 ” K (for a parallel band). The measured O2-broadening coefficients range from 0.0153 to0.0645 cm 1 atm 1 at 296 K. All the measured pressure-shifts are negative. The reported O2-induced pressure-shift coefficients vary fromabout 0.0017 to 0.0068 cm 1 atm 1. We have examined the dependence of the measured broadening and shift parameters on the J00,and K quantum numbers and also developed empirical expressions to describe the broadening coefficients in terms of m (m = J00, J00,and J00 + 1 in the QP-, QQ-, and QR-branch, respectively) and K. On average, the empirical expressions reproduce the measured broadeningcoefficients to within 4.4%. The O2-broadening and pressure shift coefficients were calculated on the basis of a semiclassical modelof interacting linear molecules performed by considering in addition to the electrostatic contributions the atom–atom Lennard-Jonespotential. The theoretical results of the broadening coefficients are generally larger than the experimental data. Using for the trajectorymodel an isotropic Lennard-Jones potential derived from molecular parameters instead of the spherical average of the atom–atom model,a better agreement is obtained with these data, especially for |m| 6 12 values (11.3% for the first calculation and 8.1% for the secondcalculation). The O2-pressure shifts whose vibrational contribution are either derived from parameters fitted in the QQ-branch of selfinducedshifts of CH3D or those obtained from pressure shifts induced by Xe in the m3 band of CH3D are in reasonable agreement withthe scattered experimental data (17.0% for the first calculation and 18.7% for the second calculation). 2005 Elsevier Inc. All rights reserved.

The first magnesium and zinc boraamidinate(bam) complexes have been synthesized via metathetical reactions between dilithio, bams and Grignard reagents or MCl2 (M = Mg, Zn). The following new classes of bam complexes have been structurally characterized: heterobimetallic spirocycles {(L)mu-Li[PhB(mu-(NBu)-Bu-t)(2)]}(2)M (6a, b, M = Mg, L = Et2O, THF; 6c, M = Zn, L = Et2O); bis(organomagnesium) complexes {[PhB(mu(3)-(NBu)-Bu-t)(2)]((MgBu)-Bu-t)(2)(mu(3)-Cl)Li(OEt2)(3)} (8) and {[PhB(mu(3)-(NBu)-Bu-t)(2)](MgR)(2)(THF)(2)} (9a, R = Pr-i; 9b, R = Ph); mononuclear complex {[PhB(mu-NDiPP)(2)]Mg-(OEt2)(2)} (10). Oxidation of 6a or 6c with iodine produces persistent pink (16a, M = Mg) or purple (16b, M = Zn) neutral radicals {L-x-mu-Li[PhB(mu-(NBu)-Bu-t)(2)](2)M}(circle) (L = solvent molecule), which are shown by EPR spectra supported by DFT calculations to be C-s-symmetric species with spin density localized on one of the bam ligands, In contrast, characterization of the intensely colored neutral radicals {[PhB(mu-(NBu)-Bu-t)(2)](2)M}(circle) (5c, M = In, dark green; 5d, M = B, dark purple) reveals that the spin density is equally delocalized over all four nitrogen atoms in these D-2d(-) symmetric spirocyclic systems. Oxidation of the dimeric dilithio complex {Li-2[PhB(mu(4)-(NBu)-Bu-t)(2)]}(2) with iodine produces the monomeric neutral radical {[PhB(mu-(NBu)-Bu-t)(2)]Li(OEt2)(x)}(circle) (17), characterized by EPR spectra and DFT calculations. These findings establish that the bam anionic radical [PhB((NBu)-Bu-t)(2)](circle-) can be stabilized by coordination to a variety of early main-group metal centers to give neutral radicals whose relative stabilities are compared and discussed.

The homoleptic aryl copper reagent [Cu(4)Dipp(4)] (Dipp=2,6-diisopropylphenyl) has been prepared and structurally characterized by a single-crystal X-ray diffraction study. Its tetrameric structure differs in significant details from that of the previously reported [Cu(4)Tripp(4)] (Tripp=2,4,6-triisopropylphenyl). The electronic structure of the cluster has been probed through B3LYP/6311G(2d,p)//B3LYP/6-31G calculations on [Cu4Ph4] constrained to D-2d symmetry. The utility of the new copper reagent is demonstrated by the preparation of pure DippPCl(2), for which the crystal structure is also reported. (c) 2006 Elsevier B.V. All rights reserved.

Developing countries - given their extreme economic vulnerability - are likely to be better served by maintaining flexible exchange rate regimes. That is the finding of this informative and enlightening book. Presenting unique theoretical and econometric analysis of the current account of the balance of payments of Nigeria and Ghana, this book examines the features common to the economic position of developing countries (such as recurring deficits and continual increases in external debt). The book presents a number of new theoretical modifications to the standard version of the value model of the current account, in order to reflect the major characteristics of developing economies. The book also uses rigorous econometric analyses to determine the validity of theoretical models, and examines the sustainability of these various countries' current account deficits.

The reaction of Cl3PNSiMe3 with 3 equiv of LiHNR (R = Pr-i, Cy, Bu-t, Ad) in diethyl ether produces the corresponding tris(amino)(imino)phosphoranes (RNH)(3)PNSiMe3 (1a, R = Pr-i; 1b, R = Cy; 1c, R = Bu-t; 1d, R = Ad); subsequent reactions of 1b-d with (BuLi)-Bu-n yield the trilithiated tetraimidophosphates {Li-3[P(NR)(3)(NSiMe3)]} (2a, R = Cy; 2b, R = Bu-t; 2c, R = Ad). The reaction of [((BuNH)-Bu-t)(4)P]Cl With 1 equiv of (BuLi)-Bu-n results in the isolation of ((BuNH)-Bu-t)(3)(PNBu)-Bu-t (1e); treatment of le with additional nBuLi generates the symmetrical tetraimidophosphate {Li-3[P(NtBu)(4)]} (2d). Compounds 1 and 2 have been characterized by multinuclear (H-1, C-13, and P-31) NMR spectroscopy; X-ray structures of 1b,c were also obtained. Oxidations of 2a-c with iodine, bromine, or sulfuryl chloride produces transient radicals in the case of 2a or stable radicals of the formula {Li-2[P(NR)(3)(NSiMe3)]LiX center dot 3THF}(center dot) (X = Cl, Br, I; R = Bu-t, Ad). The stable radicals exhibit C3 symmetry and are thought to exist in a cubic arrangement, with the monomeric LiX unit bonded to the neutral radical {Li-2[P(NR)(3)(NSiMe3)]}(center dot) to complete the Li3N3PX cube. Reactions of solvent-separated ion pair {[Li(THF)(4)]{Li(THF)(2)[(mu-(NBu)-Bu-t)(2)P(mu-(NBu)-Bu-t)(2)]Li(THF)(2)} (6) with I-2 or SO2Cl2 produce the persistent spirocyclic radical {(THF)(2)Li mu-(NBu)-Bu-t)(2)P(mu-(NBu)-Bu-t)Li(THF)(2)}(center dot) (10a); all radicals have been characterized by a combination of variable concentration EPR experiments and DFT calculations.

Fish rely on chemosensation to alert them of nearby predators. Recent evidence suggests that metals disrupt this chemical communication system. Our objective was to determine the chemical alarm response of juvenile fathead minnows after embryonic copper (Cu) exposure. Embryos were randomly assigned to one of two treatments: clean water or water containing 10 [mu]g/L Cu. Once hatched, half of the Cu-exposed embryos were transferred to clean water (after hatch), while the other half remained in the Cu-contaminated water. Fish were tested using a triumvirate maze at the age of 84-96 d post-hatch. Fish reared in clean water significantly avoided the alarm cue. However, fish reared under continuous Cu exposure and those that were only exposed to Cu during embryonic development were unable to respond to the chemical alarm stimulus. Fish from all treatments did not respond to two control stimuli. Results from this study suggest that fish exposed to elevated Cu concentrations during embryonic development is sufficient to impair chemosensory function during later life stages. This could result in an inability to detect nearby predators by olfaction, which could lead to important ecological perturbations in populations inhabiting metal-contaminated systems.

The purpose of this study was to examine relationships among water, sediment, and fish tissue metal concentrations as they relate to fish diversity, tissue metal accumulation, and fish morphometric and reproductive condition. Fish were captured in 12 lakes near Sudbury, Ontario, Canada, that ranged in their degree of metal contamination. In general, metal concentrations in water and sediment decreased with increasing distance from industrial operations. However, only Cu and Ni demonstrated this trend in sediments. Although 20 fish species were identified in the 12 lakes, only one species, yellow perch (Perca flavescens), was common to all 12 lakes. Fish diversity was only associated with sediment metals, suggesting that short-term processes are much less important than long-term processes for fish community recovery in metal-contaminated lakes. Multivariate characterization of water metal concentrations resulted in three lake clusters: Group 1 consisted of reference lakes; Group 2 lakes had high alkalinity, conductivity, hardness, pH, waterborne metals (especially Se), and sediment Cu and Ni concentrations; Group 3 lakes had high pH, waterborne and sediment Cu, and sediment Ni, intermediate alkalinity, conductivity, and waterborne metals (except Al and Fe), and low hardness and waterborne Al and Fe. Liver Cd, Cu, Ni, Pb, and Zn, muscle Zn, and intestinal Cd and Zn were highest, and muscle Cu and male gonadosomatic index (GSI) were lowest, in Group 3 fish. Liver, muscle, and intestinal Se concentrations, and Fulton's condition factor (FCF), hepatosomatic index (HSI), and male GSI were highest in Group 2 fish. Group 1 fish had the highest muscle Hg concentrations and female GSI. Muscle Se appeared to have an antagonistic effect on muscle Hg accumulation as a function of distance from smelting operations. Neither Cu nor Ni, both metals of concern in the Sudbury area, was useful for predicting fish condition, probably because of homeostatic regulatory control. Liver Cd accumulation, which was negatively related to FCF (r=-0.16; P), exhibited strong, nonlinear inhibition (r2=0.99; P) as a function of water hardness. Because Cd was not detected in water samples in this study, we suspect that branchial Ca2+ uptake may play some role in reducing dietary Cd uptake in hard water lakes. Selenium has received relatively little attention in the contaminated systems around Sudbury, yet our results demonstrated that tissue Se was related to all condition metrics studied. Moreover, evidence was provided that suggests that there is a gender-specific interaction between dietary Se and Cu uptake that may contribute to decreased female reproductive condition in wild yellow perch.

Detailed electrochemical studies in dichloromethane (0.1 M BU4NPF6) on the oxidation of the half-lantern [Pt-2-((KAs)-As-2,C -C6H3-5-Me-2-AsPh2)(2)(mu-KAS,KC-C6H3-5-Me-2-AsPh2)(2)] (1) and full-lantern [Pt-2(mu-KAS,KC-C6H3-5-Me-2-AsPh2)(4)] (2) complexes reveal the presence of an exceptionally stable dinuclear Pt cation 2(+). Thus, oxidation of 1 occurs on the voltammetric time scale via a ladder-square scheme to give 2(+), whereas 2 is directly converted to 2(+). Electrochemically informed chemical synthesis enabled the isolation of solid [2(+)][BF4-] to be achieved. Single-crystal X-ray structural analysis showed that 2(+) also has a lantern structure but with a shorter separation between the Pt centers [2.7069(3) angstrom (2(+)), 2.8955(4) angstrom (2)]. EPR spectra of 2(+) provide unequivocal evidence for axial symmetry of the complex and are noteworthy because of an exceptionally large, nearly isotropic hyperfine coupling constant of about 0.1 cm(-1). Spectroscopic data support the conclusion that the unpaired electron in the 2(+) cation is distributed equally between the two Pt nuclei and imply that oxidation of 2 to 2(+) leads to the establishment of the metal-tometal hemibond. Results of extended Huckel molecular orbital and density functional calculations on 2 and 2(+) lead to the conclusions that s, p, d2/z mixing of orbitals contributes to the large EPR Pt hyperfine coupling and also that the structural adjustments that occur upon removal of an electron from 2 are driven by the metal-metal bonding character present in 2(+).

The geometry of 15 triarylphosphines which differ in the nature of the substituents at the 2 and 6 positions of one or more phenyl rings are compared. The sum of angles around phosphorus, Sigma{angle CPC}, is used as the primary measure of steric bulk. The roles of substituents, which act as steric shields surrounding the phosphine lone pair and of those which generate steric pressure and cause flattening of the C3P pyramid are identified. Both crystallographic and computational (HF 6-31G(d)) structures are used to assess Sigma{angle CPC}, the pyramidalization angle alpha, the average C-P distance, and the helical twist angle of the aryl rings beta. All of these parameters confirm that ortho-2,6-diisopropyl substituted aryl groups generate the most sterically congested triarylphosphines. Comparison to Tolman cone angles are made where these are available. (c) 2004 Elsevier B.V. All rights reserved.

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Atlantic salmon (Salmo salar) was once native to Lake Ontario, however, its numbers rapidly declined following colonisation by Europeans and the species was extirpated by 1896. Government agencies surrounding Lake Ontario are currently undertaking a variety of studies to assess the feasibility of reintroducing Atlantic salmon. We released hatchery-reared adult Atlantic salmon into a Lake Ontario tributary to examine spawning interactions between this species and fall-spawning exotic salmonids found in the same stream. Chinook salmon, coho salmon and brown trout were observed interacting with spawning Atlantic salmon in nearly one-quarter of our observation bouts, with chinook salmon interacting most frequently. Whereas a previous investigation found that chinook salmon caused elevated agonistic behaviour and general activity by spawning Atlantic salmon, the present study found that interspecific courtship was the most common form of exotic interaction with spawning Atlantic salmon. In particular, we observed precocial male Chinook salmon courting female Atlantic salmon and defending the female against approach by male Atlantic salmon. We discuss the potential implications of these interactions on the Lake Ontario Atlantic salmon reintroduction programme

An adjustable band shape calculation model based on the strong collision approximation with inter-branch coupling has been applied to predict line mixing in the 2000)0110, 1220)0110 and in the 1110)0000 Q-branches of carbon dioxide. In this approach, the band shape is calculated using an adjustable parameter to account for line mixing effects, in addition to the usual set of spectral parameters used to describe the band shape. The good quality of the model is proven by comparisons with experimental spectra recorded at room temperature over a widepressure range (1–21 atm). All spectra were recorded using a Fourier transform spectrometer and 25 cm long temperature controlled cell. Thevalues obtained for the adjustable parameter for the three Q-branches are discussed.q 2005 Elsevier B.V. All rights reserved.

In this paper, we report measured Lorentz self-broadening and self-induced pressure-shift coefficients of 12CH3Dinthe m2 fun-damental band (m0  2200 cm1). The multispectrum fitting technique allowed us to analyze simultaneously seven self-broadenedabsorption spectra. All spectra were recorded at the McMath-Pierce Fourier transform spectrometer of the National Solar Obser-vatory (NSO) on Kitt Peak, AZ with an unapodized resolution of 0.0056 cm1. Low-pressure (0.98–2.95 Torr) as well as high-pres-sure (17.5–303 Torr) spectra of 12C-enriched CH3D were recorded at room temperature to determine the pressure-broadeningcoefficients of 408 m2 transitions with quantum numbers as high as J00 = 21 and K = 18, where K00 = K0 ” K (for a parallel band).The measured self-broadening coefficients range from 0.0349 to 0.0896 cm1 atm1 at 296 K. All the measured pressure-shiftsare negative. The reported pressure-induced self-shift coefficients vary from about 0.004 to 0.008 cm1 atm1.We have examinedthe dependence of the measured broadening and shift parameters on the J00, and K quantum numbers and also developed empiricalexpressions to describe the broadening coefficients in terms of m (m = J00, J00, and J00 + 1 in the QP-, QQ-, and QR-branch, respec-tively) and K. On average, the empirical expressions reproduce the measured broadening coefficients to within 3.6%. A semiclassicaltheory based upon the Robert–Bonamy formalism of interacting linear molecules has been used to calculate these self-broadeningand self-induced pressure-shift coefficients. In addition to the electrostatic interactions involving the octopole and hexadecapolemoments of CH3D, the intermolecular potential includes also an atom–atom Lennard–Jones model. For low K (K 6 3) with|m| 6 8 the theoretical results of the broadening coefficients are in overall good agreement (3.0%) with the experimental data.For transitions with K approaching |m|, they are generally significantly underestimated (8.8%). The theoretical self-induced pressureshifts, whose vibrational contribution is derived from results in the QQ-branch, are generally smaller in magnitude than the exper-imental data in the QP-, and QR-branches (15.2%). 2005 Elsevier Inc. All rights reserved.

The Lorentz self-broadening (halfwidths) and self-induced pressure-shift coefficients were measured for the first time in the octadregion of methane. All spectra were recorded at 0.011 cm 1 resolution using the McMath–Pierce Fourier transform spectrometerlocated at the National Solar Observatory on Kitt Peak, Arizona. 12C-enriched CH4 gas samples at room temperature were used,and high signal-to-noise ratios of 2000:1 were achieved. The multispectrum nonlinear least squares fitting technique enabled us to fitsimultaneously a total of 10 high-resolution laboratory absorption spectra consisting of six self-broadened and four air-broadenedspectra. In this paper, we report the self-broadened widths and self-induced pressure shift coefficients for 1423 transitions belongingto five bands with a maximum J of 16. The numbers of measurements by bands are: 71 for m2 + 2m4, 202 for m1 + m4, 824 for m3 + m4,58 for 2m2 + m4, and 268 for m2 + m3. The observed widths varied from 0.045 to about 0.090 cm 1 atm 1 at 296 K. The measuredpressure-shift coefficients had values extending from about 0.020 to 0.005 cm 1 atm 1 at 298.3 ± 1.2 K. The results obtainedfor the broadening coefficients in the various bands were compared with each other and with measurements reported in the literaturefor other methane bands. 2005 Elsevier Inc. All rights reserved.

Absolute intensities, self- and air-broadening coefficients, self- and air-induced shift coefficients and their temperature dependenceshave been determined for lines belonging to the P- and R-branches of the m2 band of H12C14N centered near 712 cm 1. Infraredspectra of HCN in the 14-lm region were obtained at high resolution (0.002–0.008 cm 1) using two different Fourier transformspectrometers (FTS), the McMath-Pierce FTS at the National Solar Observatory on Kitt Peak and the Bruker IFS 120HR FTS atthe Pacific Northwest National Laboratory. Spectra were recorded with 99.8% pure HCN as well as lean mixtures of HCN in air atvarious temperatures ranging between +26 and 60 C. A multispectrum nonlinear least squares technique was used to fit selectedintervals of 36 spectra simultaneously to obtain the line positions, intensities, broadening, and shift parameters. The measured lineintensities were analyzed to determine the vibrational band intensity and the Herman–Wallis coefficients. The measured self-broadeningcoefficients vary between 0.2 and 1.2 cm 1 atm 1 at 296 K, and the air-broadening coefficients range from 0.08 to0.14 cm 1 atm 1 at 296 K. The temperature dependence exponents of self-broadening range from 1.46 to 0.12 while the correspondingexponents for air broadening vary between 0.58 and 0.86. The present measurements are the first known determinationof negative values for the temperature dependence exponents of HCN-broadening coefficients. We were able to support our selfbroadeningmeasurements with appropriate theoretical calculations. Our present measurements are compared, where possible, withprevious measurements for this and other HCN bands, as well as the parameters that are included in the 2000 and 2004 editions ofthe high-resolution transmission (HITRAN) database. 2005 Elsevier Inc. All rights reserved.

Lorentz pressure-broadening and pressure-induced shift coefficients along with their temperature dependences have been determined forover forty P- and R-branch transitions in the fundamental band of 12C16O broadened with helium. A total of nineteen spectra recorded atvarious temperatures (C24 to K194 8C) in the 2010–2260 cmK1 spectral region were analyzed simultaneously using a multispectrumnonlinear least squares fitting technique. The spectra were recorded with the McMath-Pierce Fourier transform spectrometer located at theNational Solar Observatory on Kitt Peak. Present results are compared with similar measurements reported recently.q 2005 Elsevier B.V. All rights reserved.

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Stable dark red (M = Al) or dark green (M = Ga) neutral radicals {[PhB(mu-(NBu)-Bu-t)(2)](2)M}(center dot) are obtained by the oxidation of their corresponding anions with iodine, and EPR spectra supported by DFT calculations show that the spin density is equally delocalized over all four nitrogen atoms in these spiroconjugated systems.

The stoichiometric reaction of the bulky benzamidine N, N'-bis(2,6-diisopropylphenyl)-4-toluamidine (HDippAm) with the metal alkyls (BuLi)-Li-n (1 : 1 in THF), Bu2Mg (2 : 1 in THF) and Me3Al (1 : 1 in Et2O) is presented. This provides the mononuclear dihapto benzamidinate compounds [Li(DippAm)(THF)(2)] (1), [Mg(DippAm)(2)] (2) and [Al(DippAm)Me-2] (3), respectively. Compound 3 was also obtained by salt elimination using dimethylaluminium chloride and 1. All three compounds exhibit sterically strained geometries that are maintained in solution at increased temperatures. Compound 3 displays exceptional thermal and aerobic stability, while 2 constitutes a rare example of non-porphyrin supported square planar magnesium.

The line broadening and shift coefficients for CO–H2 in the fundamental and first two overtone bands are modeled using semi-classical calculations based on the Robert–Bonamy formalism and two isotropic and anisotropic intermolecular potentials. These potentials involve electrostatic contributions and (a) the atom–atom Lennard-Jones model, or (b) the Tipping–Herman model with adjustable parameters in order to fit the broadening coefficients. For the line shifts, which appear to arise only from vibrational dephasing effects, different values for the relative dependence of the attractive and repulsive parts of the isotropic potential are used. The calculated broadening and shiftparameters are then compared with experimental results available in the literature. This comparison shows a reasonable agreement of the broadening parameters and a less satisfactory agreement of the line shifts for which the experimental data are on the whole rather inaccurate.q 2005 Elsevier B.V. All rights reserved.

The EPR spectra of six 1,2,4,6-thiatriazinyls have been redetermined and simulated using modern computer simulation programs. The hyperfine coupling (hfc) constants determined from the simulations differ in some cases significantly from those reported previously. The presence of unresolved coupling also can be detected in some of the spectra. The hfc values to the two kinds of nitrogen atoms in the ring vary in a systematic fashion with the relative electron-withdrawing character of the substituents attached to the ring carbon atoms at the 3 and 5 positions.

This study evaluated the &gt;400-fold tolerance to acute waterborne Cd of a metal-tolerant fish, yellow perch (YP, Perca flavescens), relative to a sensitive model fish, rainbow trout (RBT, Oncorhynchus mykiss), from the perspective of the acute Cd biotic ligand model (BLM). Three-hour gill binding characteristics for Cd and its competitor, Ca, in both species exhibited only small quantitative differences, but gill Cd accumulations at 3 h and 24 h, which were associated with 50% lethality at 96 h (3- and 24-h LA50s), were 52- to 60-fold higher in YP relative to RBT. However, the acute Cd BLM cannot be extended from RBT to YP by simple adjustments of LA50 values because unlike RBT, in YP, LA50s (3 and 24 h) were 26- to 47-fold greater than the capacity of the characterized set of Cd-binding sites. Moreover, 3-h gill Ca and Cd binding characteristics in wild YP, collected from one clean (Geneva) and two metalcontaminated softwater lakes (Hannah and Whitson) around Sudbury region, northern Ontario, revealed that chronic waterborne factors like hardness and Cd preexposure can influence both Cd and Ca binding in fish gills and could have major implications for the future refinement of the acute Cd BLM approach.

Using both a difference frequency spectrometer and a Fourier transform spectrometer, we have measured transitions in the 12 (2)0&lt;--01 (1)0 band of carbon dioxide at room temperature and pressures up to 19 atm. The low-pressure spectra were analyzed using a variety of standard spectral profiles, all with an asymmetric component to account for weak line mixing. For this band, we have been able to retrieve experimental line strengths and the broadening and weak mixing parameters. In this paper we also compare the suitability of the energy-corrected sudden model to predict mixing in the two previously measured Q branches 20 (0)0&lt;--01 (1)0, the 11 (1)0&lt;--00 (0)0, and the present Q branch of pure CO(2), all at room temperature.

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If a circular flow of a contained rotating fluid is strained into an elliptical one in such a way that the elliptical streamlines preserve their figures in  a laboratory reference frame, the flow becomes unstable. This type of instability is known to be excited as a result of coupling between a pair of inertial modes of the contained fluid by the applied strain. The present  work is concerned with the elliptical instability of a thick, spherical,  rotating fluid shell. We have conducted experiments and have observed the excitation of the elliptical instability as well as some of the  inertial modes of a rotating fluid contained in the above mentioned geometry. The velocities of the fluid particles are captured by means of  Digital Particle Imaging Velocimetry (DPIV). Plots of the velocity vectors of the inertial modes obtained experimentally are used to identify the  modes predicted using theoretical methods. Such investigations are of geophysical interest, since tidal forcing might be sufficient to excite an elliptical instability in Earth’s fluid core as well as in other planetary  interiors.

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The reaction of ((BuNH)-Bu-1)(3)PNSiMe3 (1) with 1 equiV of (BuLi)-Bu-n results in the formation of Li[P((NHBU)-B-1)(2)((NBu)-Bu-t)(NSiMe3)] (2); treatment of 2 with a second equivalent of nBuLi produces the dilithium salt Li-2[P((NHBu)-Bu-t)((NBU)-B-t)(2)(NSiMe3)] (3). Similarly, the reaction of 1 and (BuLi)-Bu-n in a 1:3 stoichiometry produces the trilithiated species Li-3[P((NBU)-B-t)(3)(NSiMe3)] (4). These three complexes represent imido analogues of dihydrogen phosphate [H2PO4](-), hydrogen phosphate [HPO4](2-), and orthophosphate [PO4](3-), respectively, Reaction of 4 with alkali metal alkoxides MOR (M = Li, R = SiMe3; M = K, R = Bu-t) generates the imiclo-alkoxy complexes {Li-3[P((NBU)-B-t)(3)(NSiMe3)](MOR)(3)} (8, M = Li; 9, M = K). These compounds were characterized by multinuclear (H-1, Li-7, C-13, and P-31) NMR spectroscopy and, in the cases of 2, 8, and 9-3THF(1) by X-ray crystallography. In the solid state, 2 exists as a dimer with Li-N contacts serving to link the two Li[P((NHBu)-Bu-t)(2)((NBu)-Bu-t)(NSiMe3)] units. The monomeric compounds 8 and 9-3THF consist of a rare M3O3 ring coordinated to the (LiN)(3) unit of 4. The unexpected formation of the stable radical {(Me3SiN)P(mu(3)-(NBU)-B-t)(3)[mu(3)-Li(THF)](3)((OBu)-Bu-t)} (10) is also reported. X-ray crystallography indicated that 10 has a distorted cubic structure consisting of the radical dianion [P((NBU)-B-t)(3)(NSiMe3)](*2-), two lithium cations, and a molecule of (LiOBu)-Bu-t in the solid state. In dilute THF solution, the cube is disrupted to give the radical monoanion [(Me3SiN)((BuN)-Bu-t)P-(mu-(NBu)-Bu-t)(2)Li(THF)(2)](*-), which was identified by EPR spectroscopy.

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The reaction of DippPH(2) ( Dipp = 2,6-(Pr2C6H3)-Pr-i) with DippN=C(p-CH3C6H4)Cl in refluxing xylenes affords DippP=C(p-CH3C6H4)N(H) Dipp; deprotonation with alkali metal reagents produces unique lithium and potassium complexes with the ligand in a different geometry to that of the free phosphaamidine.

doi: 10.1139/Z04-034 © 2004 NRC Canada 694 Received 26 August 2003. Accepted 2 March2004. Published on the NRC Research Press Web site at http://cjz.nrc.ca http://cjz.nrc.ca on 22 June 2004. TDMcPherson and GG Pyle.1 Department of Biology, Nipissing University, PO Box 5002 ...

Room temperature values for self-broadened and hydrogen-broadened Lorentz halfwidth coefficients, and self and hydrogenpressure-induced shift coefficients have been measured for transitions with rotational quantum number m ranging between )24 and24 in the 2 0 band of 12C16O. The spectra were recorded with the McMath–Pierce Fourier transform spectrometer located at theNational Solar Observatory on Kitt Peak. The analysis was performed using a multispectrum nonlinear least squares technique. Wehave compared our results with similar measurements published recently. 2004 Elsevier Inc. All rights reserved.

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A variable-temperature single-pass absorption gas cell with an optical pathlength of 147.5 cm was designed and built for spectroscopicmeasurements of gases of atmospheric interest. The cell is optically matched to a Bomem DA8.3 Fourier transform spectrometer. Aheating/cooling system enveloping the cell, used together with a Neslab ULT-80 thermal bath, allows spectroscopic studies of gas samples attemperatures ranging from 205 to 350 K and at pressures up to 1 atm. Tests of the optical, thermal, and vacuum operation of the system wereperformed. Spectra of the 3ˆ0 vibrational–rotational band of carbon monoxide were recorded from 225 to 348 Kand used to determine therotational gas temperatures. These results were compared with values obtained using thermocouples, in order to assess the thermalperformance of the new system. A second temperature-controlled cell 25-cm long, able to withstand pressures up to 30 atm, was also used torecord CO spectra. We have recorded high-resolution FTIR spectra of CO and CO perturbed by N2 at temperatures from 295 to 348 K. Thespectra were analyzed to determine pressure broadening and pressure-induced shift coefficients, along with their temperature dependence forseveral transitions in the second overtone band of CO. The results, especially for self-broadening, are in excellent agreement with otherrecent measurements reported in the literature.q 2004 Elsevier B.V. All rights reserved.

The objective of this study was to evaluate the effects of copper exposure on swimming performance and gill-binding characteristics of wild yellow perch (Perca flavescens), a species endemic to metal-contaminated lakes of the Sudbury region in northern Ontario. Yellow perch were collected from lakes varying in the degree of metal contamination (Cu = 1-21 microg/l), on two separate occasions for the investigation of swim performance and the analysis of gill-binding characteristics. Swim performance tests indicated that yellow perch from the contaminated lake had slightly greater endurance in a fixed velocity sprint test than fish from reference lakes, although the analysis of critical swimming speeds (U(crit)) did not reveal this same distinction between the groups. Differential sprint performance was in part due to differences in fish size within contaminated and reference lakes. Yellow perch from the contaminated lake also had higher resting levels of muscle glycogen and greater lactate production during high intensity exercise compared to yellow perch from the reference site. Acclimation occurred in the metal-contaminated yellow perch, as seen by the significantly elevated time to death (LT50) during an acutely lethal challenge to 600 microg Cu/l. However, gills from perch from the contaminated lake accumulated about three times more copper at death. In contrast, at a lower exposure range of water-copper (10-400 microg/l), the gills of fish from the contaminated lake tended to saturate with copper at lower concentrations than gills of fish from the reference lake (approximately 8 microg versus 23 microg Cu/g of gill tissue). In addition, perch from the contaminated lake exhibited a lower rate of sodium loss during the acute exposure to copper at approximately 10 to 600 microg Cu/l. This study suggests that the amount of copper bound to (or accumulated within) the gills may not be diagnostic of acute toxicity for wild yellow perch from metal-contaminated lakes.

Ours is the first study to demonstrate an influence of dietary sodium on waterborne copper uptake in fish. We examined possible interactions between dietary sodium and the response of freshwater rainbow trout (Oncorhynchus mykiss) to waterborne copper in light of recent evidence of interactions between sodium and copper metabolism in the gills. Trout were maintained for 6 days on one of four diets of increasing sodium concentration (0.25 mmol g(-1), 0.51 mmol g(-1), 0.76 mmol g(-1) and 1.27 mmol g(-1), which corresponds to 0.6%, 1.2%, 1.8% and 3% sodium by mass, respectively). At the end of 7 days, fish were exposed for 6 h to waterborne copper spiked with (64)Cu to determine if the dietary sodium affected responses to a subsequent short-term waterborne copper exposure. The radiotracer allowed us to distinguish between Cu occurring in fish tissues before the experiment and 'newly accumulated' Cu arising from the experimental exposure. Dietary sodium concentrations of 1.8% or 3% reduced newly accumulated copper concentrations in gill (from 93.9 ng g(-1) in control to 38.9 ng g(-1) and 20.0 ng g(-1) in fish fed 1.8% or 3% Na(+)-supplemented diets, respectively), liver (from 64.3 ng g(-1) to 23.1 ng g(-1) and 7.5 ng g(-1), respectively), kidney (from 29.3 ng g(-1) to 11.7 ng g(-1) and 7.8 ng g(-1), respectively), plasma (from 64.7 ng g(-1) to 21.5 ng g(-1) and 10.7 ng g(-1), respectively) and gut (from 6.8 ng g(-1) to 3.4 ng g(-1) and 2.2 ng g(-1), respectively) by 50.0-88.2%. The 3% Na(+)-supplemented diets also increased plasma and gut sodium concentrations by 38.1% (from 137.1 micromol g(-1) to 189.3 micromol g(-1)) and 104.3% (from 56.5 micromol g(-1) to 115.4 micromol g(-1)), respectively, relative to fish maintained on untreated diets. Whole body uptake rates of both sodium and copper were significantly reduced, and highly correlated (r=0.97) with one another, in fish fed high-sodium diets relative to controls. Moreover, sodium efflux was 12% and 38% higher in fish fed 1.8% and 3% sodium-enriched diets, respectively. Fish fed high-sodium diets also drank more water, but the contribution of drinking to waterborne copper uptake was negligible. From these results, we speculate that, at least in part, aqueous sodium and copper share a common branchial uptake route, probably through an apical sodium channel. According to this hypothesis, as the channel is downregulated with increasing internal sodium concentrations, both sodium and copper uptake from the water are inhibited.

Juvenile rainbow trout were fed diets containing control (0.26 mmol/g) or elevated (1.3 mmol/g) dietary Na1 in combination with either background (19 nmol/L) or moderately elevated levels (55 or 118 nmol/L) of waterborne Cu for 21 d. Unidirectional waterborne Na1 uptake rates (measured with 22Na) were up to four orders of magnitude higher than those of Cu (measured with 64Cu). Chronic exposure to elevated dietary Na1 alone or in combination with elevated waterborne Cu decreased whole-body uptake rates of waterborne Na1 and Cu. Accumulation of new Cu and Na1 at the gills was positively and highly significantly correlated and responded to the experimental treatments in a similar fashion, suggesting that Na1 and Cu have common branchial uptake pathways and that dietary Na1 preexposure modifies these pathways. Chronic exposure to elevated waterborne Cu significantly increased Cu concentrations in the liver but caused only modest increases in total Cu concentrations in the whole body and gill. Chronic exposure to elevated dietary Na1 slightly decreased whole-body Cu concentration on day 14 and greatly reduced liver Cu concentration on days 14 and 21; new Cu accumulation in whole-body, gill, and internal organs was reduced on all days. Chronic exposure to elevated waterborne Cu or dietary Na1 alone reduced short-term gill Cu binding at low waterborne Cu concentrations. At high waterborne Cu concentrations, chronic exposure to elevated waterborne Cu had no effect, while elevated dietary Na1 increased Cu binding to the gills. Combined chronic exposure to elevated dietary Na1 and waterborne Cu decreased gill Cu binding over the entire range of Cu concentrations tested. Clearly, chronic exposure to elevated dietary Na1 and waterborne Cu appears to modify gill Cu-binding characteristics and may be important considerations in future development of a chronic biotic ligand model for Cu.

Two editions of the methane line parameters (line positions, intensities and broadening coe

Single-unit activity in the neostriatum of awake monkeys shows a marked dependence on expected reward. Responses to visual cues differ when animals expect primary reinforcements, such as juice rewards, in comparison to secondary reinforcements, such as tones. The mechanism of this reward-dependent modulation has not been established experimentally. To assess the hypothesis that direct neuromodulatory effects of dopamine on spiny neurons can account for this modulation, we develop a computational model based on simplified representations of key ionic currents and their modulation by D1 dopamine receptor activation. This minimal model can be analyzed in detail. We find that D1-mediated increases of inward rectifying potassium and L-type calcium currents cause a bifurcation: the native up/down state behavior of the spiny neuron model becomes truly bistable, which modulates the peak firing rate and the duration of the up state and introduces a dependence of the response on the past state history. These generic consequences of dopamine neuromodulation through bistability can account for both reward-dependent enhancement and suppression of spiny neuron single-unit responses to visual cues. We validate the model by simulating responses to visual targets in a memory-guided saccade task; our results are in close agreement with the main features of the experimental data. Our model provides a conceptual framework for understanding the functional significance of the short-term neuromodulatory actions of dopamine on signal processing in the striatum.

Precise intensities, self-broadenings and shifts have been obtained for the 12C16O v ¼ 2 0 band from simultaneous fits of lownoise,high-resolution Fourier-transform spectra at pressures from 27 to 80 kPa (200–600 Torr). Observed line shapes exhibit deviationson the order of 1% from the conventional Voigt profile, primarily due to speed-dependent broadening and secondarily toline mixing. Dicke narrowing is reduced by over an order-of-magnitude from the diffusion value, presumably because of correlationsbetween velocity- and phase-changing collisions. 2003 Elsevier Inc. All rights reserved.

The bulky primary phosphane 2,6-diisopropylphenylphosphane, DipPH(2), has been prepared from 1-bromo-2,6-diisopropylbenzene via the reaction of the Grignard reagent with PCl3. The resulting mixed phosphonous dihalides DipP(Cl,Br)(2) are reduced with LiAlH4 to yield the title compound in reasonable yield and on a synthetically useful scale. DipPH(2) is also used to prepare the monosilylated derivatives DipPHSi(CH3)(3) and DipPH{Si(CH3)(2)-t-Bu} as well as the disilylated compounds DipP{Si(CH3)(3)}(2) and DipP{Si(CH3)(2)-t-Bu}(2). All products have been fully characterized by IR, mass, and NMR spectroscopy. The crystal structure of DipPH{Si(CH3)(2)-t-Bu} was determined from single-crystal diffraction data: C18H33PSi, P2(1)/c, Z = 4, a = 8.5768(10), b = 28.104(3), c = 8.1102(4) Angstrom, beta = 93.341(3)degrees (R = 0.0518). Changes in the NMR spectrum of DipPH{Si(CH3)(2)-t-Bu} were observed over the temperature range 178-380 K. Barrier heights were determined from the peak separation at low temperature and the coalescence points: DeltaG(double dagger) approximately equal to 40 kJ mol(-1) for C(aryl)-P bond rotation and approximately equal to 72 kJ mol(-1) for pyramidal inversion at phosphorus.

Nickel (Ni) is an ubiquitous, naturally occurring metal that is associated with metal mining and other industrial activities. Despite elevated Ni concentrations reported for many industrial receiving waters, Ni receives little research attention addressing factors influencing its toxicity to freshwater fish. This study examined the influence of water hardness, pH, and total suspended solids (TSS) in soft, reconstituted water on Ni toxicity to larval fathead minnows (Pimephales promelas). Increasing water hardness from 20 to 140 mg/L (as CaCO3) reduced acute Ni toxicity by 5-fold (96-h LC50s 0.45 and 2.27 mg Ni/L, respectively). Low pH had a slight protective effect against Ni toxicity relative to neutral pH conditions. At pH 5.5, the 96-h LC50 was 0.69 mg Ni/L, compared to 0.54 mg Ni/L at pH 7.0. However, Ni toxicity was significantly reduced at pH 8.5 where the 96-h LC50 was 2.21 mg Ni/L. These results were explained on the basis of Ni speciation. Total suspended solids also reduced Ni toxicity (expressed as 96-h LC50s) from 0.35 to 1.12 mg Ni/L over a TSS range of 10 to 100 mg/L. This reduction of toxicity due to TSS is significant because mine effluents often have a combination of elevated TSS and metals. The ameliorative effect of TSS was not as significant as high hardness or pH probably because there is a TSS threshold, after which physical irritation to fish gills counteracts any protective effect conferred by TSS. This finding is relevant to choices made in design of mine effluent treatment systems; i.e., there may be an optimum range of TSS concentrations that protect aquatic biota against effects of metals that remain after treatment.

Elevated concentrations of arsenic, nickel, and molybdenum in aquatic systems around northern Saskatchewan uranium mines are an environmental concern. Early life stage fathead minnows were used to assess toxicity from several aquatic systems near the Key Lake and Rabbit Lake uranium operations. Hatching success of fish embryos exposed to waters receiving contaminants associated with uranium ore milling was reduced by 32-61% relative to controls. Mortality differed in two lakes receiving mill effluents because of opposing factors influencing metal toxicity (i.e. low pH and high hardness). In one mill receiving water (Fox Lake), larval mortality was 0%, whereas mortality was 85% in water collected from a downstream location (Unknown Lake). Fish embryos exposed to open-pit dewatering effluent receiving waters, or water from a flooded open pit (i.e. pit waters), hatched 26-39% earlier than those exposed to reference or control water. The combination of low water hardness and elevated nickel concentrations in pit waters contributed to the early hatching. Egg hatchability and hatching time were more sensitive indicators of toxicity than 'standard' endpoints, like larval mortality and growth. Current regulatory emphasis on single contaminants and standard toxicological endpoints should be re- evaluated in light of the complex interaction among confounding variables such as pH, hardness. conductivity, and multi-metal mixtures.

Chorus tenure is the number of nights that a male anuran spends attending choruses, and dominant tenure is the number of nights that a male adopts a dominant (i.e. territorial) mating tactic. While male bullfrogs that have longer tenure (chorus tenure and dominant tenure) acquire more mates, tenure is believed to be energetically costly, During the summer of 1998, we tested the hypothesis that tenure of bullfrogs is energy constrained, by conducting a feeding experiment to manipulate energetic condition, and by measuring each male’s body condition on every night of his chorus tenure. The energetic constraint hypothesis did not adequately predict variation in male chorus tenure. However, male bullfrogs with longer dominant tenures, other things being equal, were in better initial condition, poorer final condition and lost condition more slowly than males with shorter dominant tenures. Feeding had no significant effect on either chorus tenure or dominant tenure. We found evidence that direct selection through endurance rivalry favoured traits in male bullfrogs that increased tenure. (C) 2001 The Association for the Study of Animal Behaviour

The effects of chronic exposure to waterborne Cd and elevated dietary Ca, alone and in combination, were examined in juvenile rainbow trout, Oncorhynchus mykiss. Fish were chronically exposed to 0.05 (control) or 2.56 microg/l Cd [as Cd(NO3)2*4H2O] and were fed 2% body mass/day of control (29.6 mg Ca/g) or Ca-supplemented trout food (52.8 mg Ca/g as CaCl2*2H2O). Cd accumulated mainly in gill, liver, and kidney. Waterborne Cd inhibited unidirectional Ca uptake from water into the gill and induced hypocalcemia in the plasma on day 40. Waterborne Cd also induced an elevated Ca concentration on day 20 in the gill tissue of trout fed the Ca-supplemented diet and a decreased Ca concentration on day 35 in the gills of trout fed the control diet. Dietary Ca protected against Cd accumulation in gill, liver, and kidney, but did not protect against the inhibition of Ca uptake into the gill or plasma hypocalcemia. When fed Ca-supplemented diet and exposed to waterborne Cd, fish showed 35% mortality, compared to 0-2% in control fish and in the Cd-exposed fish with normal Ca in the diet. Growth, on the other hand, was not affected by any treatment.

The paper uses panel data on Ugandan firms and a measure of idiosyncratic uncertainty to determine the nature of investment sensitivity to changes in perceived uncertainty among firms with different degrees of investment reversibility. Using a sample selection technique to fit a modified version of an accelerator model, the paper yielded results consistent with predictions of theories of irreversible investment. The results indicate a negative relationship between uncertainty and investment. Findings also indicate that uncertainty has a greaternegative effect on investment for firms with less reversible investment.

Larval fathead minnows (Pimephales promelas) were placed at four exposure sites for 7 days in each of five lakes surrounding the Key Lake uranium mine in northern Saskatchewan, Canada. Fish placed in lakes receiving Mo-contaminated mill effluent demonstrated higher mortalities than those placed in lakes receiving Ni-contaminated mine-dewatering effluent, which was not significantly different from reference sites. No significant differences were detected in fish growth among the study lakes because of the high (90%) mortality in Fox and Unknown lakes. Principal components analysis characterized exposure sites by total- and dissolved-metal concentration. Stepwise multiple regression of fish mortality on principal components (PCs) generated from total-metal data showed that PC1 could account for 84% of the variance associated with fish mortality. Careful examination of the metals that correlated strongly with PC1 and with fish mortality suggested that dietary Se toxicity probably resulted in the differential fathead minnow mortality observed among study lakes.

We have measured the room temperature, widths, pressure shifts, and line asymmetry coefficientsfor many transitions of the first overtone band of CO and CO perturbed by N2 . The broadeningcoefficients were obtained with an accuracy of about 1%. The pure CO profiles have been fitted bya Voigt profile while the CO–N2 spectral profiles have been fitted with a Lorentz and an empiricalline shape model (HCv) that blends together a hard collision model and a speed-dependent Lorentzprofile. In addition to the Voigt, Lorentz, and HCv models, we have added a dispersion profile toaccount for weak line mixing. The line broadening and shift coefficients are compared tosemiclassical calculations employing a variety of intermolecular interactions. The line asymmetryresults are compared to line mixing calculations based on the energy corrected sudden ~ECS! model. The results indicate that effects other than line mixing also contribute to the measured lineasymmetry. © 2000 American Institute of Physics. @S0021-9606~00!01425-2#

This review is a critical overview of the literature on electrochemistry of unsaturated ring-compounds containing bonds between Group 15 and Group 16 elements (principally S and N), including metallacycles. It contains a detailed compilation of measured redox potentials and the conditions under which these were obtained for over 200 compounds. An introduction to the application of solution electrochemistry to this class of compounds is provided, and the relevance of such measurements to materials design is discussed. (C) 2000 Elsevier Science B.V. All rights reserved.

Using a difference frequency spectrometer we have measured the Q(2) to Q(38) 2000Ã0110,SÃP transitions of carbon dioxide at 296 K and pressures up to 15 kPa. These low pressure spectrawere analyzed using both the Voigt model, and an empirical line shape that blends together a hardcollision model and a speed dependent Lorentzian profile. The broadening coefficients wereobtained with an accuracy of 1% or better. The low density or first order low pressure line mixingparameters were also determined. We have compared both our measured low pressure line-mixingparameters and the complete band spectrum at high pressures with those predicted by a relaxationmatrix calculated from an EPG fitting law. Spectra at the highest pressures were recorded using boththe difference frequency spectrometer and an FTIR spectrometer, the temperature for the latterexperiments being 303 K. The vibrational band intensity and linear pressure shift of the branch asa whole were also measured. © 2000 American Institute of Physics. @S0021-9606~00!01519-1#

A dynamical model is proposed for the elliptical instability that has been reported by Aldridge et al. [Aldridge, K.D., Seyed-Mahmoud, B.,  Henderson, G.A., van Wijngaarden, W., 1997.  Elliptical instability of the Earth’s fluid core. Phys. Earth Planet. Inter., 103, 365–374] in connection with recent experiments on an ellipsoidal shell of rotating fluid. The frequencies and growth rates of the instability are obtained numerically  by means of a Galerkin method that is based upon the normal modes of the contained fluid. A finite-element method has been employed to  approximately solve the ill-posed Poincare´ problem for the normal  modes. The numerical results for a special case are compared with their  analytical counterparts, and the agreement is to within 0.1% for shells of small ellipticity. Results are presented for other cases, including some where the boundary perturbation is allowed to rotate slowly with respect to the inertial frame. The conclusion is that such investigations are of  geophysical interest, since tidal forcing might be sufficient to excite an  elliptical instability of the fluid outer core of the Earth and thus contribute to the geomagnetic field.

The reaction of N,N'-bis(2,6-diisopropylphenyl)carbodiimide with lithium 2,6-diisopropylanilide, quenching with water and recrystallization from heptane produces the symmetric guanidine [DipNH](2)C=NDip which crystallizes in the triclinic system, space group P(1) over bar, a = 10.6513(11), b = 10.8997(11), c = 16.2961(17) Angstrom, alpha = 80.524(12), beta = 78.921(13), gamma = 70.060(12)degrees, V = 1735.2(3) Angstrom (3), Z = 2. The molecule crystallizes with three perpendicular 2,6-diisopropylphenyl groups, which surround and shield the central CN3 unit, and provide (almost) three-fold symmetry around the central atom. Its dynamic solution behaviour has been studied by VT NMR between -90 and +180 degreesC, and is consistent with three distinct barriers to N-C-Ar rotation. Preliminary estimates of the Gibbs free energy of activation for the lower two barriers are 56 +/- 2 and 73 +/- 2 kJ mol(-1). Reaction of the title compound with Mo(CO)(6) in refluxing n-heptane produces [DipNH](2)C=NDip.Mo(CO)(3), a complex in which Mo(CO)(3) is eta (6)-coordinated to one of the diisopropylphenyl rings.

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Re-examining David Lynch’s Eraserhead in the context of recent studies and developments in body theory, the author suggests that the malformed infant is a complex textual body which carries many more potential meanings than our contemporary culture is willing to prescribe. By employing an opposition of the "open" versus "closed" body, Lynch critiques dominant readings and depictions of the infantile body as a site of innocence, transforming it, instead, into a locus of horror and astonishment in an endless chain of signifiers.

N,N'-bis-(2,6-diisopropylphenyl)trifluoroacetamidine has been prepared for the first time from 2,6-diisopropylaniline and the trifluoroacylation reagent TFAP via the imidoylchloride. The crystal structure of the amidine was determined, indicating that it crystallizes in the Z-anti tautomer, in contrast to the nonfluorinated analogue, which is Z-anti in the solid state. In solution, as indicated by NMR spectroscopy, it exists in two isomeric forms. The amidine reacts with Mo(CO)(6) to produce a coordination complex with Mo(CO)(3) in which the ligand is also in the Z-anti geometry, the metal is eta(6)-coordinated to the imino-2,6-diisopropylphenyl ring, and the amino N-H unit is directed towards the metal, as determined by a single-crystal X-ray structure. Unlike the analogous nonfluorinated acetamidine, there is no indication of an intermediate in which the neutral amidine is coordinated in a monodentate fashion to an Mo(CO)(5) unit, which we now attribute to the predominant geometry of the ligand, both in the solid state and in solution, being Z-anti. The high steric bulk of this superamidine ligand apparently prevents the formation of a metal-metal bonded Mo-2(amidinate)(4) as observed previously in a redox reaction between N,N'-diphenylbenzamidine and Mo(CO)(6) under similar thermal reaction conditions.

The rotationally resolved infrared spectrum of the nu(1) band of the long-lived (a) over tilde(1)Delta electronic state of the CCO radical has been observed between 1918 and 1970 cm(-1) using a tunable diode laser spectrometer. Metastable CCO was produced in a discharge through a flowing mixture of carbon suboxide and helium. Fifty eight rovibrational transitions in the P and IZ branches and the five lowest J lines in the Q branch were measured. The band origin was determined to be 1942.8515(19) cm(-1). This is in close agreement to the values determined previously from photoelectron spectroscopy of CCO-. (C) 1999 American Institute of Physics. [S0021-9606(99)00902-2].

We have measured the width, G, of many P and R lines of the fundamental vibration–rotation band of CO perturbed by N2at 348 K and pressures of about 50 kPa. We have also extended the measurements made earlier at room temperature. Thebroadening coefficients, g 5 G/pressure, were obtained with an accuracy of 0.3% by fitting with a Lorentzian, a Voigt, andan empirical lineshape model that blends together a hard-collision model and a speed-dependent Lorentzian profile. In all casesthe results are represented by an empirical exponential power law polynomial in the line number, m. Combining the data atthe two temperatures yields the exponent n in the scaling law g(T1)/g(T2) 5 (T1/T2)2n, as a function of line number. Thebroadening coefficients and the variation of the temperature exponent line number are compared with theory. In addition, theline-mixing parameters are also reported at 348 and 301 K.

We have used a three-channel version of a tunable difference frequency laser spectrometer to measure the collisionallyinduced lineshifts at room temperature for 26 lines of the fundamental band of CO perturbed by nitrogen. Each lineshift wasobtained directly by comparing the line center positions of two simultaneous recordings, one for a pressure-shifted line, andthe other for the same line in pure CO line at very low pressure. The experimental results are found to be in complete agreementwith earlier measurements and confirm that shifts as small as 3 MHz may be measured in such a system. Our results arecompared with theoretical calculations. The part of the shifting coefficient antisymmetric with respect to a change in sign ofthe line number m, is in disagreement with the calculations. © 1999 Academic Press

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The air oxidation of the cluster compounds [Li2E((NBu)-Bu-t)(3)](2) (E = S, Se) in toluene produces deep blue (E = S) or green (E = Se) solutions. The ESR spectra of these solutions consist of a septet (1:3:6:7:6:3:1) of decuplets. The simulation of these spectra shows that the secondary hyperfine splitting results from interaction of the unpaired electron with three equivalent Li-7 ions consistent with the formation of the neutral radicals {Li-3[E((NBu)-Bu-t)(3)](2)}(.) (4a, E = S, g = 2.0039, a(N-14)= 5.69 G, a(Li-7) = 0.82 G; 4b, E = Se, g = 2.00652, a(N-14) = 5.41 G, a(Li-7) = 0.79 G). Over a period of 25 h the seven line pattern of 4b is replaced first by a five line (1:2:3:2:1) spectrum (g = 2.009, a(N-14) = 13.4 G) and, subsequently, by a three line (1:1:1) spectrum (g = 2.00946, a(N-14) = 15.4 G, a(Se-77) = 3.3 G), neither of which exhibit 7Li hyperfine splitting. These spectra are tentatively assigned to the radical anions SeO((NBu)-Bu-t)2(.-) and SeO2((NBu)-Bu-t)(.-), respectively. The cluster (Li-2[O2S((NBu)-Bu-t)]), (3) is prepared by the reaction of sulfur dioxide with 2 equiv of (LiNHBu)-Bu-t in toluene. The air oxidation of toluene solutions of {Li-2[OS((NBu)-Bu-t)(2)]}(6) (2a) or 3 produces deep blue species. In the former case the initial ESR spectrum is a 1:2: 3:2:1 quintet (g = 2.009, a(N-14) = 13.3 G) which, after 16 h, evolves into a 1:1:1 triplet (g = 2.008X, a(N-14) = 15.9 G). The same triplet is observed in the ESR spectrum of oxidized solutions of 3 leading to the assignments OS((NBu)-Bu-t)(2)(.-) and O2S((NBu)-Bu-t)(.-) for the quintet and triplet, respectively. The disproportionation 2OS((NBu)-Bu-t)(2)(.-) --> OS((NBu)-Bu-t)(.-) + S((NBu)-Bu-t)(3)(.-) is indicated by the changes observed for the ESR spectra of oxidized solutions of 2a.

We present in this work a high-resolution Fourier transform infrared study of the OH-bending vibrational band of 13have investigated the 1070–1400 cm1 spectral region at 0.002 cm1 resolution using the modified Bomem DA3.002 FourierCH3 1338 cm1 transform spectrometer at the Steacie Institute for Molecular Sciences at the National Research Council of Canada in Ottawa. Thisstudy has led to (i) determination of excited-state J(J  1) subband expansion coefficients and (ii) characterization of a variety ofinteractions coupling the different vibrational modes, notably a strong Fermi resonance between the OH bend and the torsionallyexcited CH3 have been fitted to J(J  1) power-series expansions in order to obtain the subband origins and the state-specific energy expansioncoefficients for both the OH-bending and excited torsional CH3 and the first excited torsional CH3 asymmetry splitting of the (n K)v (122)runusual behavior, but a quantitative analysis of the vibrational coupling is restricted by limited knowledge of the unperturbedpositions of the interacting levels. All these interactions provide relaxation channels for intramolecular vibrational redistributionamong the lower vibrational modes in 13CH3OH-bending state display an inverted pattern compared to the ground state. © 1998 Academic Press

This paper presents a high-resolution Fourier transform infrared study of the first CO-stretch overtone band of13CH3OH. The spectrum has been recorded at the Justus-Liebig University, Gießen, Germany on their Bruker IFS 120HR Fourier transform spectrometer. We have assigned parallel subbands in the torsional state n  0 for K values up to6. Each individual subband has been fitted to a J(J / 1) power series expansion in order to obtain the subband originand the state-specific energy expansion coefficients for the first CO-stretch overtone state. The average rotational constantB in the CO-stretch £CO  2 state was found to be 0.768 cm01 , forming a smooth series with that of 0.777 cm01 obtainedin the £CO  1 state and the ground state value of 0.787 cm01 . Modeling of the excited state torsion–vibration energylevel structure derived from the subband origins is then discussed and molecular parameters in the £CO  2 state areproposed. The value obtained for the barrier height to internal rotation is 377.06 { 0.52 cm01 , nearly indistinguishablefrom the value 378.65 cm01 reported for the CO-stretch £CO  1 state. The vibrational energy is found to be 2020.9 {1.4 cm01 . The harmonic wavenumber for the CO-stretch vibration in 13CH3OH was calculated to be v  1029.9 cm01 .The anharmonicity constant of this vibration is vx  6.5 cm01 , giving x  6.3 1 1003 . We have also observedasymmetry-induced K doubling for the subbands of A symmetry for K values from 1 to 3 at sufficiently high J values.The size of the splitting coefficients is similar to those observed for the CO-stretch fundamental (14) , with the exception of those for the K  3A doublet, where the observed splitting is about 18% larger than that for the ground and COstretch£CO  1 states. 1998 Academic Press

The 2 nu(1) - nu(1) and nu(1) + nu(3) - nu(3) difference bands of the CCO radical in the gas phase have been studied using a tunable infrared diode laser spectrometer. The CCO radical was produced using a flowing mixture of carbon suboxide and helium subjected to a hollow-cathode discharge. The spectral region between 1920-1960 cm(-1) was probed. Ninety and seventy-five rovibrational transitions were measured in the 2 nu(1) - nu(1) and nu(1) + nu(3) - nu(3) bands, respectively. The analyses of these bands yielded spectroscopic constants for the (001), (200), and (101) vibrational states. The band origins for 2 nu(1) - nu(1) and nu(1) + nu(3) - nu(3) determined to be 1941.85761(54) cm(-1) and 1936.79402(56) cm(-1), respectively. (C) 1998 American Institute of Physics.

A reanalysis of the n3 , n4 , and n6 interacting bands of D2CO has been carried out in the region 850–1250 cm01 using high-resolution Fourier transform spectra recorded at Giessen. As compared to the previous study of these bands (1987, K. Nakagawa, R. H. Schwendeman, and J. W. C. Johns, J. Mol. Spectrosc. 122, 462–476) higher J and Ka transitions were assigned for the three bands, leading to a better determination of the upper state constants. The £3  1, £4  1, and £6  1 experimental energy levels were introduced in a least-squares fit calculation together with the microwavemeasurements available in the literature in order to obtain the upper state parameters (band centers, rotational and coupling constants) . In this calculation, which allowed us to reproduce both the infrared and the microwave measurements to within their experimental accuracies, the A-, B-, and C-type Coriolis interactions involving the rotational levels belonging to the £4  1 and £6  1, £3  1 and £4  1, and £3  1 and £6  1 interacting states respectively were explicitly taken into account. Finally, from the intensities, a new determination of the relative values of the q3 , q4 , andq6 first derivatives of the D2CO dipole moment was performed. q 1998 Academic Press

Equilibrium conditions are often assumed in dose and risk calculations based on the simple linear concentration factor model, a commonly used model in the study of contaminant flow through ecosystems. It has been argued that by using a power function model to describe radionuclide retention in fish, equilibrium may never be achieved under natural conditions, thereby violating the equilibrium requirement in the concentration factor model. Our results demonstrate uranium-series radionuclide equilibria in a natural population of common white sucker (Catostomus commersoni). Concentration factors indicated that 226Ra, 232Th, 230 Th, and 228Th preferentially deposited in bone over muscle. Although 226Ra had the highest concentration in bone, 228Th yielded the highest concentration factors for water-to-bone transfer. 232Th may not be in equilibrium because of a growth dilution effect.

The crystal structure of the title compound was determined at 250 K in space group I (4) over bar 2m, a = 20.661(5) Angstrom, c = = 6.764(7) Angstrom, Z = 8. The individual dithiadiazole rings form two sets of contrarotatory 4-member pinwheels clustered around a 4-fold rotation-inversion axis located halfway along the unit cell edges, describing an infinite channel lined with sulfur atoms but in which there are short intra-stack contacts through only one S atom of each CN(2)S(2) group. The double-layer stacking occurs in order to accommodate the bulk of the (t)Bu group, and the spacing between layers is very regular, with short and long S ... S contacts of 3.48(2) and 3.61(2) Angstrom and considerable thermal motion in the c direction. The title compound and its SbF(6)(-) salt are oxidized at +0.81 V (in CH(2)Cl(2)) and at +0.61 V (in CH(3)CN), while a reduction process is observed only in CH(2)Cl(2) at -0.73 V vs. SCE. Magnetic susceptibility data between 5 and 400 K demonstrate at very low temperature that the sample follows the Curie-Weiss law, theta = 0 K, and chi(0) =-156 ppm emu mol(-1). The free-spin concentration at T = 0 K is approximate to 1.3%, due to paramagnetic defects in an essentially diamagnetic structure. The diamagnetism starts to lift above 210 K; above 260 K, a strong antiferromagnetic exchange is operative. These results are consistent with the lifting of the Peierls distortion in this structure, starting above approximate to 200 K. The crystal structure of the parent diamidine 5-tert-butyl-1,3-[(Me(3)Si)(2)NCNSiMe(3)](2)C(6)H(3) was determined in C2/c with a = 10.0788(3), b = 21.328(5), c = 20.876(5) Angstrom, beta = 99.41(2)degrees, Z = 4. The two amidine functional groups are equivalent by crystal symmetry.

\N,N'-Bis(2,6-diisopropylphenyl)-4-toluamidine, -4-anisylamidine and -acetamidine have been prepared for the first time from 2,6-diisopropylaniline and the acid chlorides via the: corresponding imidoyl chlorides. The crystal structures of all three amidines were determined, indicating that the first is a disordered mixture of Z-anti and E-syn tautomeric forms, the second Z-anti, and the third E-anti in the solid state. Despite these differences, all three form identical coordination complexes with Mo(CO), in which the ligand is in the Z-anti geometry, and the metal is pi-coordinated to the imino 2,6-diisopropylphenyl ring, and the amino N-H unit is directed towards metal. The coordination mode was confirmed by single-crystal X-ray structure determination of the toluamidine and methylamidine complexes with Mo(CO),. In the case only of the methylamidine, an isolable intermediate is first formed in which the neutral amidine is coordinated in a monodentate fashion to an Mo(CO)(5) unit. The crystal structure of this complex shows that the ligand is in the E-anti geometry, with the imino nitrogen coordinated to Mo, d(Mo-N) = 2.352(2) Angstrom. The structures are closely related in that the initial Mo(CO)(5) N-coordination sets up the metal for conversion to the more thermodynamically stable pi-coordinated Mo(CO)(3) complex. The high steric bulk of these superamidine ligands is seen in the failure of any of them to form the metal-metal bonded Mo-2(amidinate)(4) complexes typically prepared using common, less bulky, amidines.

The elliptical instability of a rotating fluid contained in a thick spherical  shell has been excited in our laboratory by a tide-like perturbation of the  flexible inner boundary. For an inviscid fluid, the growth rate of the   instability is approximately proportional to the perturbation amplitude   and the rotation rate. Development of the instability appears to be limited  by the spherical outer surface and the relatively small perturbation  applied over the inner surface. If the corresponding instability were  excited in the Earth's fluid core by tidal forces, in the absence of  dissipation the e-folding time for growth would be on the order of several  thousand years. Although this time scale is similar to current estimates  for the time needed for the geomagnetic field to undergo a reversal, the  instability would grow at a rate equal to the difference between the ideal  growth rate and the overall decay rate. The rates of viscous and  electromagnetic damping are determined by material properties of the  core fluid that are not well known. If elliptical instability plays a central role in geomagnetic reversals, upper limits on the viscosity and  conductivity of the fluid core might be inferred.

The Fourier transform infrared spectrum of the in-plane CH3-rocking fundamental of 13CH3OH has been investigated at 0.002 cm21 resolution. The rocking band is principally of parallel character and has a double-peaked Q branch and relatively wide spread subbands indicative of a substantialchange in torsional barrier height. All A subbands from K50 to 11 and all but one E subband fromK50 to 9 have been assigned in the n50 torsional state and fitted to J(J11) power-seriesexpansions to obtain the subband origins and excited-state energy structure. The effects ofvibrational interactions between the CH3-rocking and CO-stretching modes are prominent in thespectrum. Coriolis coupling between rocking (K21) and CO-stretching K levels is observable forK&gt;6, and makes significant contributions to the subband origins and effective B values. SeveralJ-localized perturbations due to level-crossing resonances with CO-stretch states have beenobserved and characterized. Two reported strong far-infrared laser lines optically pumped by the10R(26) CO2 laser line have been found to arise through such a DK53 level-crossing resonance.Modeling of the rocking-state torsion-K-rotation energies yields a height of V3 r 5469.2(38) cm21for the torsional potential barrier, a 26% increase over the ground state. The asymmetry K-doublingpattern in the excited state is qualitatively consistent with this barrier for K52 to 4, but the K55 rocking substate displays strongly enhanced splitting. © 1997 American Institute of Physics.@S0021-9606~97!01929-6#

The infrared absorption spectrum of the CCO radical has been studied in an extension of the original observation of the C-O stretching vibration by Yamada et al. [J. Chem. Phys. 84 (1985) 2573]. The CCO radical was generated using a flowing mixture of carbon suboxide and helium subjected to a hollow-cathode discharge. The spectral region between 1930-1990 cm(-1) was probed using a tunable diode laser spectrometer. Transitions with N-values up to 40 were measured for the nu(1) fundamental and nu(1) + nu(2) - nu(2) sequence bands. Their analysis yielded band origins, rotational, centrifugal distortion, spin-spin interaction, and spin-orbit interaction parameters for the lower and upper vibrational states, and l-doubling parameters for the degenerate bending states upsilon(2) = 1 and (upsilon(1) = 1, upsilon(2) = 1). In particular, the band origins for nu(1) and nu(1) + nu(2) - nu(2) were determined to be 1970.86332(41) cm(-1) and 1960.13093(37) cm(-1), respectively. (C) 1997 Published by Elsevier Science B.V.

The rotational millimeter-wave spectrum of CH318OH has been revisited, and 162 transitions of both a- and b-types have been measured in the 119-165 GHz spectral range. The spectrum was recorded using thefrequency-modulated millimeter-wave spectrometer at the/ustus-Liebig-Universit~it in Giegen. The CH318OH transition assignments were basedon energy levels obtained from the far-infrared analysis of S. Zhao (Ph.D.thesis, University of New Brunswick, 1993) using the "Ritz" program ofG. Moruzzi et al. (J. Mol. Spectrosc. 167, 156 (1994)) for direct energylevel fitting. The relatively low residuals between calculated and observed frequencies highlight the good quality of the results from this program. The newly measured transitions combined with those existent in the literature have been included in least-squares fits to improve the set of rotational,torsional and centrifugal distortion constants for O-18 methanol.

The ground state rotational spectrum of CD3OH has been revisited in the millimeter-wave range. A total of 216transition frequencies have been measured and assigned in the 117–179 GHz spectral range, including about 40 transitionspreviously reported. The spectrum was recorded at the Justus–Liebig University in Gießen, Germany using a frequencymodulated millimeter-wave spectrometer. The assignments for the CD3OH transitions were predicted based on energylevels calculated using preliminary results of the global fit of microwave, millimeter-wave, and far-infrared data ofWalsh et al. (Paper FC04 presented at the 52nd International Symposium of Molecular Spectroscopy, Columbus, OH,1997) . The new measurements have substantially enlarged the accurate millimeter-wave component of the data setavailable for the global fit and have allowed Walsh et al. to obtain significant improvement in the CD3OH molecularparameters ( J. Mol. Spectrosc. 188, 85–93, 1998) . The low residuals between observed and calculated frequencieshighlight the quality of the global fit results. 1998 Academic Press

Uptake of 226Ra, 232Th , 23OTh, and 228Th from water, sediment, and diet sources to bone and muscle of white suckers (Catostomus commersoni) was studied in sixteen lakes in the uranium-mining district of Ontario, Canada. Fish tissues did not increase linearly with environmental concentrations. The best relationship appears to be a power function. This has implications for the accuracy of radiological dose and risk estimates for uranium mining impacts, which are often based on a linear model.

Equilibrium conditions are assumed in the simple linear concentration factor model commonly used in simulations of contaminant flow through ecosystems and in dose and risk calculations. Predictions derived from a power function model have suggested that if the time scale of the food-chain transfer is less than six years in fish, radium226 equilibrium will not be achieved in nature, thereby violating the equilibrium requirement in the concentration factor model. Our results indicate "Ra equilibrium is achieved in a natural population of lake herring (Coregonus artedii), contrary to predictions of the power function model.

Torsionally excited n51 and n52 subbands of the CO-stretching fundamental have been assignedin the Fourier transform infrared spectrum of 13CH3OH recorded at a resolution of 0.002 cm21. Forthe n51 torsional state, subbands with K values up to 7 have been identified for A torsionalsymmetry and up to 5 for E symmetry. For n52, four subbands have so far been assigned. Subbandorigins have been obtained by fitting the observed wave numbers to J(J11) power-seriesexpansions. The expansion parameters represent the data compactly to close to the experimentaluncertainty in the absence of line blending or perturbations. Significant downshifting of the n51origins is observed, correlated closely with proximity to the n50 OH-bending state. J-localizedperturbations have been observed and characterized for several subbands. Two of the far-infraredlaser lines optically pumped by the 10R~14! CO2 laser line have been assigned. © 1996 AmericanInstitute of Physics. @S0021-9606~96!01029-X#

Molybdenum and tungsten chlorides, chloride oxides and chloride nitrides as well as thiazene and phosphazene metallacycles were studied by electrochemical methods in CH2Cl2. The different ligand systems have a profound influence on the redox potentials. The stabilization of high valency increases from the hexachloro to pentachlorooxo to chloronitrido complexes and the metallacycles. There is a systematic difference in the electrode potentials between molybdenum and tungsten redox couples. The geometries of the d(1) and d(0) species, optimized using density functional methods, are in good agreement with the available experimental data and trends in redox data are reproduced by the computed energy difference between the appropriate d(1)/d(0) pair. The relative stability of the higher oxidation state is directly linked to the donor properties of the ligands present, and increases in the order: Cl-6 < F-6 < Cl5O < Cl-4(N3S2) < Cl-N?3P?2 < Cl4N.

The eight-membered ring in the title compound, C10H18N4S2, lies about an inversion centre and is essentially planar with normal bond lengths and angles [mean c-s 1.569 (2) and mean c-N 1.326 (3) Angstrom].

The analysis of the title compound, C8H7N2OSe2, shows that its crystals are composed of weakly linked dimers, with intramolecular Se-Se distances of 2.343(3) and 2.345(2)Angstrom, intermolecular Se ... Se distances of 3.193(3) and 3.316(3)Angstrom and lateral Se ... Se interactions of 3.514(2) and 3.579 (3) Angstrom.

The title compounds have been studied in CH2Cl2 by cyclic voltammetry. Nonacarbonyldi(mu(3)-methylidyne)triiron, [Fe-3(CO)(9)(mu(3)-CX)(2)] (X = F, Cl, Br, H), undergo chemically reversible 1e(-) reduction (-0.72 to -0.88 V vs. SCE) and irreversible oxidation (+1.59 to +1.72 V); the compound for which X = F displays a second, irreversible reduction (-1.96 V). Using reduction potentials of comparable mu(3)-E (E = S, Se, NPh, PPh) clusters, mu(3)-methylidyne ligands are shown to be strongly basic, comparable to PPh and NPh and more basic than S or Se. The methylidyne clusters are both more difficult to oxidize and reduce than isomeric alkyne clusters [Fe-3(CO)(9)(C(2)R(2))], indicative of greater thermodynamic stability. The complexes previously formulated as [Fe-2(CO)(6)(S(2)N(2)CC(6)H(4)X)] (X = H, CF3, OCH3) are reversibly reduced (-1.59 to -1.70 V) and irreversibly oxidized (+1.0 to 1.3 V), unlike free dithiadiazole radicals, which are reversibly oxidized around +0.8 V. This behaviour is not consistent with the ring-centered free radical claimed for the case where X = H; instead we find conclusive evidence that these are diamagnetic complexes of the 3-H-1,2,3,5-dithiadiazolines, [Fe-2(CO)(6)(S2N{NH}CC(6)H(4)X)] (nu(NH) = 3376-3381 cm(-1); delta(NH) = 6.55-7.1 ppm). Dicyclopentadienyl-dithiadiazoledinickel, [Ni(2)Cp(2)(S2N2CC6H5)], is both reversibly reduced (-0.79 V) and oxidized (+0.45 V); and irreversibly oxidized at +1.9 V. This is consistent with an unpaired electron, and only the nickel cluster has an ESR signal (g = 2.0410, no resolved hyperfine splitting). Extended Huckel theory locates the free electron in a SOMO restricted to Ni, C, and S atoms.

High-resolution Fourier transform studies of the CO-stretching and CH3-rocking bands of 13CH3OH have beenapplied to the assignment of far-infrared (FIR) laser transitions optically pumped by CO2 infrared (IR) lasers. Theassignments are based on spectroscopic identification of the IR pump transitions at the reported offsets from the CO2laser lines and agreement between the FIR laser wavenumbers and values calculated from IR/FIR combination-looprelations. Wavenumbers are also predicted for further potential new FIR laser lines in transition systems that couldbe pumped by CO2 and ~3CO2 cw and waveguide lasers.

Cyclic and ac voltammetry were carried out on 17 different 1,2,3,5-dithia- or diselenadiazole radicals under vacuum in CH2Cl2 and CH3CN solutions containing NBu(4)PF(6) electrolyte. The redox potentials for the oxidation and reduction processes are reported, referenced to SCE using ferrocene as a secondary standard. The oxidation process for five of the dithiadiazole radicals correlates linearly with the gas-phase ionization energies previously obtained from UV-PES, and the damping influence of the solvent medium is evident. Disproportionation energies defined as E(cell) = -{E(oxid) - E(reduc)} were calculated: (E = S, -1.43 +/- 0.06 V in CH3CN and -1.61 +/- 0.06 V in CH2Cl2 (average of 11 compounds); E = Se, -1.25 +/- 0.03 in CH3CN and -1.39 +/- 0.05 V in CH2Cl2 (average of six compounds)) and compared to the enthalpies of the same process in the gas phase obtained from MNDO calculations (E(cell)(gas) = -6.5 V). Both calculation and experiment show that the title compounds, by comparison with TTF+, TCNQ(-), and other related compounds, have higher than desirable disproportionation energies which is a disadvantage for their use in constructing molecular metals. The electrochemistry of 1,4-bis(dithia- and diselenadiazolyl)benzene has also been investigated by voltammetry and coulometry. These bifunctional diradicals undergo independent redox chemistry in each CN(2)E(2) ring, and the ''oxidation'' process involves a two-electron transfer confirmed by coulometry. The disproportionation energies of these compounds are shown to be similar to those of the monofunctional radicals; by implication the same limitations apply to their solid-state properties.

4-CF3-C6H4-CN3S2, 1, forms symmetrical sulfur-bound adducts with norbornene (NBE), norbornadiene (NBD), and 1-heptene (C7H14), which were studied by H-1, C-13, COSY-45, and HETCORR NMR. 1NBE exists in solution in a single isomeric form which corresponds to that found in the solid state for 4-CH3O-C6H4-CN3S2.NBE by single-crystal X-ray diffraction: orthorhombic, P2(1)2(1)2(1) with Z = 4, a = 10.224(3), b = 10.369(5), c = 14.075(5). R = 0.0475 and R(w) = 0.0492 for 634 data. 1 NBD exists in solution in two isomeric forms which are not interchangeable. One of these corresponds to that found in the NBE adduct, i.e. exo addition; the other is the first example of endo addition. Two bis adducts of stoichiometry NBD.21 have been prepared and separated. They are isomers exhibiting eno-exo and exo-endo addition. The structure of the latter was confirmed by X-ray diffraction: orthorhombic, Pcab with Z = 8, a = 7.816(2), b = 17.264(3), c = 36.842(5). R = 0.068 and R(w) = 0.106 for 1506 data. 1.C7H14 exists as a mixture of syn and anti isomers. NMR structure parameters derived here have been applied to published data on over 15 thiazene NBE and NBD adducts.

The preparation and isolation in the solid state of five aryl 1,2,3,5-dithia- and diselenadiazolyls is reported. The structure of the dimer of 4-Cl-C6H4-CN2S2 in the solid state was obtained: monoclinic, C2/c with Z = 8, a = 20.982(10), b = 10.058(3), c = 15.867(6) angstrom, beta = 93.34(4)-degrees, R = 0.066, R(w) = 0.053 for 1099 data. Cyclic voltammetry shows reversible oxidation to a 6 pi cation for all 10 compounds in both CH2Cl2 and CH3CN; reversible reduction to an 8pi anion is observed in CH2Cl2 for all except X = CF3, E = S. The reductions are only quasi-reversible in CH3CN for E = Se. The oxidation process is independent of chalcogen type; the reduction process is found to be about 0.2 V more negative for E = S vs E = Se.

Electrochemical studies of 5, 6, 7 and 8-membered rings containing catenated C-N-S and C-N-Se groups have been undertaken using cyclic and a.c. voltammetry. The results find a satisfying interpretation using semi-empirical MO theory. The results provide an important insight into the utility of such ring systems for the design of molecular metals.

The metallacycles [NPPh(2)NPPh(2)NMCl(3)], M=Mo, W have been studied in CH2Cl2 using cyclic voltammetry. The observed redox potentials indicate that the cyclic pi-base ligand, [NPPh(2)NPPh(2)N](3-), is capable of stabilising high oxidation states in both molybdenum and tungsten complexes. Empirical MO calculations are presented which rationalize the electronic structure of the metallacycles.

The reduction processes of the volatile hexafluorides TeF6 and SeF6 have been studied in CH2Cl2 using electrochemical methods with a vacuum-tight electrochemical cell. At -78-degrees-C the half-wave potential for the [TeF6]0/2- step occurs at - 0.88 V vs. SCE, while the less reversible [SeF6]0/2- reduction is observed at the more positive potential, E1/2 = - 0.1 V. The complex ion [TeF7]- is irreversibly reduced in MeCN at - 0.7 V. These results are interpreted using an orbital framework. The results of Extended Huckel calculations on model systems are discussed. In each case, reduction results in the population of a metal-ligand antibonding orbital which is dominated by the metal valence s orbital.

Electrochemical studies of 1,2,3,5-dithiadiazole complexes with iron carbonyl and nickel cyclopentadienide are reported. These are consistent with paramagnetism only in the latter. The former are in fact complexes of the dithiadiazole imine. Initial investigation of routes to ferrocene-linked dithiadiazoles are described. Electrochemistry of cyanoferrocene and ferrocene-1H-tetrazole is reported.

The reactions of S4N4 with CpM(CO)x and Cp*M(CO)x (M = Mn, Fe, Co, Ni and Rh) result in tractable products only when M = Co. The electrochemical behaviour of the previously known complexes CPCoS2N2 and Cp*CoS2N2 has been investigated by DC and AC cyclic voltammetry. Each has a single one-electron reduction process occurring at -0.65 V (Cp) and -0.99 V (Cp*). vs. SCE, in CH2Cl2 solution. For the Cp complex, chemical reduction using cobaltocene has also been achieved. 15N NMR spectra were recorded for 99% N-15 enriched samples: 550 (broad singlet) and 431 (singlet) for Cp, 518 (broad singlet) and 404 ppm (singlet) for Cp*, referenced to liquid NH3. The electronic absorption spectra are also reported, and interpreted in the light of EHMO calculations.

New preparative routes to the title compounds are reported in which the yields are substantially improved over previous methods. In one method, reaction of O2 With a mixture of XC6H4CN2S2+Cl- and Ph3Sb leads to the products in 40-60% yield. In another, the reaction of the same salts with silylated amidines XC6H4C{NSiMe3}N(SiMe3)2 in a 1:1 mol ratio leads to the same compounds in 18-65% yield. The syntheses of 3,7-(XC6H4)2{CN2S2N2C}, X = H, 4-CH3, 4-CH3O, 4-Cl, 4-CF3, and 3-CF3, are reported. Mixed derivatives were also prepared, but not isolated as pure compounds. The crystal structure of the 4-CF3 compound has been determined by X-ray diffraction; triclinic, P1BAR with Z = 1; cell dimensions: a = 6.835(2), b = 9.936(3), c = 6.320(2) angstrom, alpha = 96.44(3)degrees, beta = 102.88(3)degrees, gamma = 88.42(3)degrees. R = 3.4%, R(w) = 3.5% for 1100 data. The eight-membered ring is flat with equivalent bond lengths between any two types of atoms, indicative of a delocalized electron distribution. The 10pi central aromatic rings have been oxidized and reduced in CH2Cl2 using voltammetric methods. The reversible one-electron reduction step gives stable 11pi species. The resistance to oxidation of the title compounds is contrasted to the ease of oxidizing 3,7-[(CH3)2N]2{CN2S2N2C}, in accordance with earlier chemical studies.

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The synthesis of XC6H4CN5S3, XC6H4CN3S2Cl2, {XC6H4CN3S2}2, and XC6H4CN3S2.C7H10 (X = 4-CH3, 4-Cl, 3-CF3, 4-CF3, 4-CH3O, 4-C6H5) is reported. The crystal structure of {4-ClC6H4CN3S2}2 was determined by a single-crystal X-ray diffraction study. The compound crystallizes in the triclinic space group P1BAR with Z = 2 in a cell of dimensions a = 6.107 (1) angstrom, b = 12.070 (2) angstrom, c = 13.206 angstrom, alpha = 113.73 (1)-degrees, beta = 99.04 (2)-degrees, and gamma = 97.53 (2)-degrees. The least-squares refinement with anisotropic thermal parameters for all non-hydrogen atoms converged at R = 0.084 for 1480 unique reflections. The structure is a cofacial dimer of 4-ClC6H4CN3S2 units, with short S...S contacts of 2.509 (4) and 2.534 (4) angstrom. Dimer units are stacked head-to-tail in the crystal along the bc diagonal. H-1-NMR studies of the more soluble compounds show significant shielding of the aromatic protons (0.3-0.6 ppm) attributable to ring currents of adjacent aromatic rings. This is consistent with the preservation in solution of the wedge-shaped dimeric structure found in the solid state.

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