Ultra-fast relaxation of electrons in wide-gap dielectrics

Low-energy electrons scattered in the conduction band of a dielectric solid should behave like Bloch electrons and will interact with perturbations of the atomic lattice, i.e. with phonons. Thus the phonon-based description of low-energy scattering within an energy band structure of a solid bears certain advantages against common free-electron scattering mechanisms. Moreover, the inelastic scattering is described by the dielectric energy loss function. With these collective scattering models we have performed the simulation of excited electron relaxation and attenuation in the insulator SiO2. After excitation to a mean initial energy of several eV their energy relaxation occurs within a short time interval of 200 fs to full thermalization. There is a very rapid impact ionization cooling connected with cascading of electrons at the beginning during the first 10 fs, followed by much slower attenuation due to phonon losses in wide-gap dielectrics and insulators

Electron beam charging of insulators: A self-consistent flight-drift model

International audienceElectron beam irradiation and the self-consistent charge transport in bulk insulating samples are described by means of a new flight-drift model and an iterative computer simulation. Ballistic secondary electron and hole transport is followed by electron and hole drifts, their possible recombination and/or trapping in shallow and deep traps. The trap capture cross sections are the Poole-Frenkel-type temperature and field dependent. As a main result the spatial distributions of currents j(x,t), charges, the field F(x,t) and the potential slope V(x,t) are obtained in a self-consistent procedure as well as the time-dependent secondary electron emission rate sigma(t) and the surface potential V0(t) For bulk insulating samples the time-dependent distributions approach the final stationary state with j(x,t)=const=0 and sigma=1. Especially for low electron beam energies E0=4 keV the incorporation of mainly positive charges can be controlled by the potential VG of a vacuum grid in front of the target surface. For high beam energies E0=10, 20, and 30 keV high negative surface potentials V0=−4, −14, and −24 kV are obtained, respectively. Besides open nonconductive samples also positive ion-covered samples and targets with a conducting and grounded layer (metal or carbon) on the surface have been considered as used in environmental scanning electron microscopy and common SEM in order to prevent charging. Indeed, the potential distributions V(x) are considerably small in magnitude and do not affect the incident electron beam neither by retarding field effects in front of the surface nor within the bulk insulating sample. Thus the spatial scattering and excitation distributions are almost not affected

Electronic Trap Microscopy - A New Mode for Scanning Electron Microscopy (SEM)

Insulating layers on conducting substrate are investigated by means of secondary electron field emission SEFE in a digital SEM. The kinetics of charge storage and release with time and temperature are controlled and recorded by an external computer.The evaluation is performed pixel-wise with respect to electronic trap concentration nt0, trap capture cross section σc and thermal activation energy Et. Mapping of these trap parameters indicates hidden inhomogenities, defects and pre-treatments of the dielectric layers as well as the pattern of thermal bleaching and release of electrons. The latter ones appear as inhomogeneous processes starting with blinking centers and increasing their concentration with time and temperature

Electron Beam Charging of Insulators with Surface Layer and Leakage Currents

International audienceThe electron beam induced selfconsistent charge transport in layered insulators is described by means of an electron-hole fight-drift model FDM and an iterative computer simulation. Ballistic secondary electrons and holes, their attenuation and drift, as well as their recombination, trapping, and detrapping are included. Thermal and field-enhanced detrapping are described by the Poole-Frenkel effect. Furthermore, an additional surface layer with a modified electric surface conductivity is included which describes the surface leakage currents and will lead to particular charge incorporation at the interface between the surface layer and the bulk substrate

Cannabinoids Occlude the HIV-1 Tat-Induced Decrease in GABAergic Neurotransmission in Prefrontal Cortex Slices

In the era of combined antiretroviral therapy (cART), human immunodeficiency virus type 1 (HIV-1) is now considered a chronic disease that specifically targets the brain and causes HIV-1-associated neurocognitive disorders (HAND). Endocannabinoids exhibit neuroprotective and anti-inflammatory properties in several central nervous system (CNS) disease models, but their effects in HAND are poorly understood. To address this issue, whole-cell recordings were performed on young (14 – 21 day old) C57BL/6J mice. We investigated the actions of the synthetic cannabinoid WIN55,212-2 (1 μM) and the endocannabinoid N-arachidonoyl ethanolamine (anandamide; AEA, 1 μM) in the presence of HIV-1 Tat on GABAergic neurotransmission in mouse prefrontal cortex (PFC) slices. We found a Tat concentration dependent (5 – 50 nM) decrease in the frequency and amplitude of miniature inhibitory postsynaptic currents (mIPSCs). The cannabinoid 1 receptor (CB1R) antagonist rimonabant (1 μM) and zero extracellular calcium prevented the significant Tat-induced decrease in mIPSCs. Further, bath-applied WIN55,212-2 or AEA by itself, significantly decreased the frequency, but not amplitude of mIPSCs and/or spontaneous IPSCs (sIPSCs), and occluded a further down-regulation of IPSCs by Tat. Pretreatment with rimonabant but not the CB2R antagonist AM630 (1 μM) prevented the WIN55,212-2- and AEA-induced decrease in IPSCs frequency without any further Tat effect. Results indicated a Tat-induced decrease in GABAergic neurotransmission, which was occluded by cannabinoids via a CB1R-related mechanism. Understanding the relationship between Tat toxicity and endocannabinoid signaling has the potential to identify novel therapeutic interventions to benefit individuals suffering from HAND and other cognitive impairments

Consolidation of Belief in Two Logics of Evidence

Recently, several logics have emerged with the goal of modelling evidence in a more relaxed sense than that of justifications. Here, we explore two of these logics, one based on neighborhood models and the other being a four-valued modal logic. We establish grounds for comparing these logics, finding, for any model, a counterpart in the other logic which represents roughly the same evidential situation. Then we propose operations for consolidation, answering our central question: What should the doxastic state of a rational agent be in a given evidential situation? These operations map evidence models to Kripke models. We then compare the consolidations in the two logics, finding conditions under which they are isomorphic. By taking this dynamic perspective on belief formation we pave the way for, among other things, a study of the complexity, and an AGM-style analysis of rationality of these belief-forming processes

Syndrome respiratoire aigu après inhalation de sprays imperméabilisants

Au cours de l'hiver 2002-2003, le Centre suisse d'information toxicologique a enregistré une augmentation inhabituelle de troubles respiratoires après exposition à des sprays imperméabilisants utilisés pour l'imprégnation du cuir et des textiles. Plus de 150 cas ont ainsi été rapportés. De telles épidémies sont déjà survenues au cours des vingt dernières années dans divers pays. Sur le plan clinique, des symptômes de toux, dyspnée et fièvre apparaissent dans le minutes ou les heures qui suivent l'exposition. Certains patients présentent une détresse respiratoire aiguë nécessitant une hospitalisation en soins intensifs. L'évolution clinique est favorable en quelques jours dans la majorité des cas, mais une dyspnée ou une toux chroniques pourraient persister chez certains patients. Un récent changement de formulation chimique semble être la cause de l'épidémie survenue en Suisse. Les produits incriminés ont été retirés de la vente. De nouveaux cas pourraient toutefois survenir à l'avenir en lien avec l'utilisation accrue de sprays imperméabilisants durant l'hiver et la possible commercialisation de nouveaux produits. [¨Résumé des Auteurs] A la suite de l'épidémie survenue en Suisse, l'Office fédéral de la santé publique a fait classer tous les sprays imperméabilisants pour cuirs et textiles dans la classe de toxicité 5S. Leurs emballages comporteront donc davantage d'avertissements aux utilisateurs. Il est actuellement recommandé d'employer ces sprays à l'air libre, d'éviter de s'exposer au brouillard de vaporisation (ne pas employer le spray contre le vent), et de bien laisser sécher les articles imperméabilisés à l'extérieur. L'emploi à l'intérieur est à éviter. Il ne suffit pas d'ouvir une fenêtre. Les personnes atteintes de maladies respiratoires (par exemple, asthme) devraient éviter d'utiliser elles-mêmes ces produits et ne pas se tenir à proximité d'un endroit où ils sont employés. [Auteurs, p. 2177]]]> Aerosols ; Respiratory Tract Diseases ; Environmental Exposure fre oai:serval.unil.ch:BIB_28738 2022-05-07T01:13:32Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_28738 Substances végétales toxiques et allergisantes. Giroud, C info:eu-repo/semantics/bookPart incollection 2003 Plantes, Pollen &amp; Allergies, vol. 3, pp. 50-63 oai:serval.unil.ch:BIB_28738FE2CF5F 2022-05-07T01:13:32Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_28738FE2CF5F Comparative Studies of Fluoroquinolones in the Treatment of Urinary Tract Infections info:doi:10.1093/clinids/10.supplement_1.s153 info:eu-repo/semantics/altIdentifier/doi/10.1093/clinids/10.supplement_1.s153 Malinverni, R. Glauser, M. P. info:eu-repo/semantics/article article 1988 Clinical Infectious Diseases, vol. 10, no. Supplement_1, pp. S153-S163 info:eu-repo/semantics/altIdentifier/pissn/1537-6591 info:eu-repo/semantics/altIdentifier/pissn/1058-4838 eng oai:serval.unil.ch:BIB_28739 2022-05-07T01:13:32Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_28739 Grössenselektive personenbezogene Staubprobenahme : Verwendung offenporiger Schäume Möhlmann, C. Aitken, R. J. Kenny, L. C. Görner, P. Vu Duc, T. Zambelli, G. info:eu-repo/semantics/article article 2003 Gefahrstoffe - Reinhaltung der Luft, vol. 63, no. 10, pp. 413-416 info:eu-repo/semantics/altIdentifier/pissn/0949-8036 ger oai:serval.unil.ch:BIB_28740 2022-05-07T01:13:32Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_28740 Intellectuelle ou militante? le serpent de mer fait son numéro. Kraus, C Malbois, F Messant, F Pannatier, G Perrin, C info:eu-repo/semantics/article article 2003 Nouvelles Questions Féministes, vol. volume 22, n° 1, pp. 4-12 oai:serval.unil.ch:BIB_28742 2022-05-07T01:13:32Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_28742 Poétique et dramaturgie: les didascalies de personnage. Exemple du théâtre de Georges Ferydeau. Myszkorowska, M info:eu-repo/semantics/article article 2003 Pratiques, vol. 119-120, pp. 35-66 oai:serval.unil.ch:BIB_286DBB5FB136 2022-05-07T01:13:32Z openaire documents urnserval <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_286DBB5FB136 Low-grade glioma: a challenge in therapeutic options: the role of radiotherapy. info:doi:10.1093/annonc/mdn434 info:eu-repo/semantics/altIdentifier/doi/10.1093/annonc/mdn434 info:eu-repo/semantics/altIdentifier/pmid/18790954 Baumert, B.G. Stupp, R. info:eu-repo/semantics/review article 2008 Annals of Oncology, vol. 19, no. Suppl 7, pp. vii217-vii222 info:eu-repo/semantics/altIdentifier/pissn/1569-8041 Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Chemotherapy, Adjuvant; Dacarbazine; Glioma; Humans; Lomustine; Neoplasm Recurrence, Local; Procarbazine; Prognosis; Radiotherapy; Radiotherapy Dosage; Vincristine eng https://serval.unil.ch/resource/serval:BIB_286DBB5FB136.P001/REF.pdf http://nbn-resolving.org/urn/resolver.pl?urn=urn:nbn:ch:serval-BIB_286DBB5FB1362 info:eu-repo/semantics/altIdentifier/urn/urn:nbn:ch:serval-BIB_286DBB5FB1362 info:eu-repo/semantics/publishedVersion info:eu-repo/semantics/openAccess Copying allowed only for non-profit organizations https://serval.unil.ch/disclaimer application/pdf oai:serval.unil.ch:BIB_286DD50ABE29 2022-05-07T01:13:32Z openaire documents urnserval <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_286DD50ABE29 Cycling to Work : An Analysis of the Practice of Utility Cycling info:doi:10.1007/978-3-030-62256-5 info:eu-repo/semantics/altIdentifier/doi/10.1007/978-3-030-62256-5 urn:isbn:9783030622558 info:eu-repo/semantics/altIdentifier/isbn/9783030622558 urn:isbn:9783030622565 info:eu-repo/semantics/altIdentifier/isbn/9783030622565 info:eu-repo/semantics/altIdentifier/pissn/2191-530X info:eu-repo/semantics/altIdentifier/pissn/2191-5318 Rérat, Patrick info:eu-repo/semantics/book book 2021 <![CDATA[This book presents a thorough discussion of utility cycling, cycling in the urban environment, and everyday mobility. It is based on large survey answered by 14,000 participants in the bike to work action in Switzerland, and quantifies the various dimensions of utility cycling. It proposes an innovative theoretical framework to analyse and understand the various dimensions of the uses of bikes and their diversity. It addresses the factors that motivate commuters to get on their bike, and highlights the barriers to this practice between deficient infrastructures and lack of legitimacy. This research makes a diagnosis and discusses the way to develop this sustainable mode of transportation. By combining quantitative results in the form of tables, figures, and maps, and including qualitative results in the form of quotations from survey participants, this book provides a thorough and enjoyable read. It will be of interest to researchers, policy makers, advanced students in the field of urban planning, social sciences, and transportation

First Results on In-Beam gamma Spectroscopy of Neutron-Rich Na and Mg Isotopes at REX-ISOLDE

After the successful commissioning of the radioactive beam experiment at ISOLDE (REX-ISOLDE) - an accelerator for exotic nuclei produced by ISOLDE - first physics experiments using these beams were performed. Initial experiments focused on the region of deformation in the vicinity of the neutron-rich Na and Mg isotopes. Preliminary results show the high potential and physics opportunities offered by the exotic isotope accelerator REX in conjunction with the modern Germanium gamma spectrometer MINIBALL.Comment: 7 pages, RNB6 conference contributio