680 research outputs found
Vibrational and rotational state dependence of dissociative attachment in e-H2 collisions
Resonant scattering theory is applied to the calculation of e-H2 dissociative attachment cross sections near threshold for several vibrational and rotational states of the H2 molecule. Typical values just above threshold are, in cm2, 2.8Ă10â21 for the ground state (v=0, J=0), 8.3Ă10â20 for (1, 0), 1.0Ă10â18 for (2, 0), and 3.5Ă10â20 for (0, 10). The effect of rotational excitation is found to be significant, although it is not as large as suggested by Chen and Peacher
Calculations of ionâion recombination rates at high pressures
The classical theory of ionâion recombination in gases of high density is extended to allow for arbitrary ratios of the masses of the three species involved. Calculations are performed for the recombination of Ar+, Ar+ 2, Kr+, and Kr+ 2 ions with Fâ and of Hg+ and Ar+ with Clâ in an argon gas. The effective twoâbody rates peak between 2Ă10â6 and 3Ă10â6 cm3âsecâ1 at pressures above 1 atm
Dissociative attachment and vibrational excitation in low-energy collisions of electrons with H2 and D2
A semiempirical analysis is made of the contributions of the two lowest resonant states to dissociative attachment and vibrational excitation in low-energy collisions of electrons with H2 and D2. The resonance models are based both on ab initio calculations and on fits to experimental data. The dissociative-attachment cross section near threshold is enhanced significantly by vibrational or rotational excitation of the initial molecule. Near 10 eV, contributions from both resonances are required to explain the observed cross sections for vibrational excitation
Fall 2007 Visiting Speaker Series
Speakers include:
Andrew Herod, University of Georgia. Fighting Communism through Urban Planning: The AFL-CIO\u27s Housing Programs in Latin America and the Caribbean during the 1960sJan Bardsley, University of North Carolina at Chapel Hill. Princess, Geisha, Beauty Queen: Women and Democracy in Cold War JapanDonald N. Clark, Trinity University. The Two Koreas: Lessons from the Past, Hope for the Futurehttps://egrove.olemiss.edu/croft_spe/1000/thumbnail.jp
The roles of agricultural biodiversity in the McLaren Vale landscape
Douglas K. Bardsley, Elisa Palazzo, Nathanael D. Wiseman, and Randy Stringe
Annihilation rate in positronic systems by quantum Monte Carlo: e(+)LiH as test case
An accurate method to compute the annihilation rate in positronic systems by means of quantum Monte Carlo simulations is tested and compared with previously proposed methods using simple model systems. This method can be applied within all the quantum Monte Carlo techniques, just requiring the accumulation of the positron-electron distribution function. The annihilation rate of e(+)LiH as a function of the internuclear distance is studied using a model potential approach to eliminate the core electrons of Li, and explicitly correlated wave functions to deal with all the remaining particles. These results allow us to compute vibrationally averaged annihilation rates, and to understand the effect of the Li+ electric field on positron and electron distributions. (C) 2002 American Institute of Physics
RNA Sequencing Reveals Novel Transcripts from Sympathetic Stellate Ganglia During Cardiac Sympathetic Hyperactivity.
Cardiovascular disease is the most prevalent age-related illness worldwide, causing approximately 15 million deaths every year. Hypertension is central in determining cardiovascular risk and is a strong predictive indicator of morbidity and mortality; however, there remains an unmet clinical need for disease-modifying and prophylactic interventions. Enhanced sympathetic activity is a well-established contributor to the pathophysiology of hypertension, however the cellular and molecular changes that increase sympathetic neurotransmission are not known. The aim of this study was to identify key changes in the transcriptome in normotensive and spontaneously hypertensive rats. We validated 15 of our top-scoring genes using qRT-PCR, and network and enrichment analyses suggest that glutamatergic signalling plays a key role in modulating Ca2+ balance within these ganglia. Additionally, phosphodiesterase activity was found to be altered in stellates obtained from the hypertensive rat, suggesting that impaired cyclic nucleotide signalling may contribute to disturbed Ca2+ homeostasis and sympathetic hyperactivity in hypertension. We have also confirmed the presence of these transcripts in human donor stellate samples, suggesting that key genes coupled to neurotransmission are conserved. The data described here may provide novel targets for future interventions aimed at treating sympathetic hyperactivity associated with cardiovascular disease and other dysautonomias
Resonant contributions to single charge transfer between He++ and He
Energy levels and lifetimes are calculated for the resonant states that are important in radiative single charge transfer in He2+-He collisions at thermal energies. The resonant contribution to the charge-transfer rate decreases with increasing temperature and is approximately 12% of the total rate at 300 K
Mobility of α particles in helium
The mobility of α particles in helium gas is calculated using the zeroth-order Viehland-Mason theory with interaction potentials recently computed by Cohen and Bardsley. The results show a dependence on field strength similar to the measurements of Johnsen and Biondi but are lower in magnitude by about 5%
Identifying and explaining framing strategies of low carbon lifestyle movement organisations
This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.Over the last decade we have seen the growth and development of low carbon lifestyle movement organisations, which seek to encourage members of the public to reduce their personal energy use and carbon emissions. As a first step to assess the transformational potential of such organisations, this paper examines the ways in which they frame their activities. This reveals an important challenge they face: in addressing the broader public, do they promote 'transformative' behaviours or do they limit themselves to encouraging 'easy changes' to maintain their appeal? We find evidence that many organisations within this movement avoid 'transformative' frames. The main reasons for this are organisers' perceptions that transformational frames lack resonance with broader audiences, as well as wider cultural contexts that caution against behavioural intervention. The analysis draws on interviews with key actors in the low carbon lifestyle movement and combines insights from the literatures on collective action framing and lifestyle movements.This research was supported by grant RES-628-25-0059 for the project âCommunity-based initiatives for energy savingâ which is part of the RCUK Energy and Communities Programme and ESRC grant RES-595-28-0001 which funded the project âThe Third Sector and the Environmentâ within the Third Sector Research Centre at the University of Southampton. We would like to thank Rebecca Edwards for collecting interview data on the âthird sectorâ project, as well as our colleagues on the Energy and Communities project for their role in the wider project design, including Patrick James, Tom Rushby and Nicholas Woodman. We are also very grateful to our research participants without whom this research would not have been possible. All remaining weaknesses remain our responsibility
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