Fokker-Planck type equations with Sobolev diffusion coefficients and BV drift coefficients

In this paper we give an affirmative answer to an open question mentioned in [Le Bris and Lions, Comm. Partial Differential Equations 33 (2008), 1272--1317], that is, we prove the well-posedness of the Fokker-Planck type equations with Sobolev diffusion coefficients and BV drift coefficients.Comment: 11 pages. The proof has been modifie

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SEP NESTER S2

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SEP NESTER S2I translated by A.M. Dujardi

Approximating a Wavefunction as an Unconstrained Sum of Slater Determinants

The wavefunction for the multiparticle Schr\"odinger equation is a function of many variables and satisfies an antisymmetry condition, so it is natural to approximate it as a sum of Slater determinants. Many current methods do so, but they impose additional structural constraints on the determinants, such as orthogonality between orbitals or an excitation pattern. We present a method without any such constraints, by which we hope to obtain much more efficient expansions, and insight into the inherent structure of the wavefunction. We use an integral formulation of the problem, a Green's function iteration, and a fitting procedure based on the computational paradigm of separated representations. The core procedure is the construction and solution of a matrix-integral system derived from antisymmetric inner products involving the potential operators. We show how to construct and solve this system with computational complexity competitive with current methods.Comment: 30 page

J.M.G. Le Clézio et Édouard Glissant: pour une poétique de la trace

En utilisant les textes que J.M.G Le Clézio et Edouard Glissant ont écrits pour la collection Peuples de l’eau aux éditions du Seuil, cet article analyse la façon dont les deux auteurs repensent la notion d’interculturalité à partir du concept de trace. Ces traces ce sont tout d’abord les signes et les voix qu’ils découvrent lors de leur découverte des îles de la Pentecôte et de Pacques, îlots isolées dans l’immensité de l’océan Pacifique. Suivre ces traces devient pour eux une manière de mettre en avant la dette de l’Occident envers la mémoire de ces peuples mais aussi une invitation à l’imaginaire et au récit pour restaurer un sens caché et perdu. En somme, il s’agira de voir comment une poétique de la trace leur permet de repenser notre rapport aux autres tout en suivant ce que Glissant appelle ‘L’imaginaire des peuples'

Detecting the influence of initial pioneers on succession at deep-sea vents

© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS One 7 (2012): e50015, doi:10.1371/journal.pone.0050015.Deep-sea hydrothermal vents are subject to major disturbances that alter the physical and chemical environment and eradicate the resident faunal communities. Vent fields are isolated by uninhabitable deep seafloor, so recolonization via dispersal of planktonic larvae is critical for persistence of populations. We monitored colonization near 9°50′N on the East Pacific Rise following a catastrophic eruption in order to address questions of the relative contributions of pioneer colonists and environmental change to variation in species composition, and the role of pioneers at the disturbed site in altering community structure elsewhere in the region. Pioneer colonists included two gastropod species: Ctenopelta porifera, which was new to the vent field, and Lepetodrilus tevnianus, which had been rare before the eruption but persisted in high abundance afterward, delaying and possibly out-competing the ubiquitous pre-eruption congener L. elevatus. A decrease in abundance of C. porifera over time, and the arrival of later species, corresponded to a decrease in vent fluid flow and in the sulfide to temperature ratio. For some species these successional changes were likely due to habitat requirements, but other species persisted (L. tevnianus) or arrived (L. elevatus) in patterns unrelated to their habitat preferences. After two years, disturbed communities had started to resemble pre-eruption ones, but were lower in diversity. When compared to a prior (1991) eruption, the succession of foundation species (tubeworms and mussels) appeared to be delayed, even though habitat chemistry became similar to the pre-eruption state more quickly. Surprisingly, a nearby community that had not been disturbed by the eruption was invaded by the pioneers, possibly after they became established in the disturbed vents. These results indicate that the post-eruption arrival of species from remote locales had a strong and persistent effect on communities at both disturbed and undisturbed vents.The authors received funding from National Science Foundation grant OCE-0424953, WHOI Deep Ocean Exploration Institute, WHOI Summer Student Fellow program, Woods Hole Partnership in Education Program, IFREMER and CNRS, Fondation TOTAL Chair Extreme Marine Environment, Biodiversity and Global change

Infrared absorption cross-sections in HITRAN2016 and beyond: expansion for climate, environment, and atmospheric applications

Spectroscopic analysis of hydrocarbons, halocarbons and related species is required in atmospheric applications such as climate-change research, tracking of pollution and biomass burning, and remote sensing. Critically evaluated line-by-line spectroscopic data are needed for such analyses. To address this need we report the large addition of spectra to the HITRAN2016 database. This extension increases the number of molecules in the database by almost a factor of 6 from that in HITRAN2012. Spectra from the Pacific Northwest National Laboratory database (Appl. Spectrosc. 2004;58:1452–61) and the Hodnebrog et al. compilation (Rev Geophys 2013;51:300–78) have been integrated into HITRAN2016. Spectra from high-resolution laboratory observations, predominantly from Fourier transform spectrometers, are now provided for 328 compounds in the IR spectral range. Spectra for atmospherically-important compounds organized by chemical category are presented. The HITRAN infrastructure (www.hitran.org), HITRAN Application Programming Interface (HAPI), and best practices for searching and downloading data are discussed

Charge and current-sensitive preamplifiers for pulse shape discrimination techniques with silicon detectors

New charge and current-sensitive preamplifiers coupled to silicon detectors and devoted to studies in nuclear structure and dynamics have been developed and tested. For the first time shapes of current pulses from light charged particles and carbon ions are presented. Capabilities for pulse shape discrimination techniques are demonstrated.Comment: 14 pages, 12 figures, to be published in Nucl. Inst. Meth.

Особенности процесса распылительной сушки высоковлажной биомассы Spirulina platensis

Проведен комплекс исследований по распылительному обезвоживанию биомассы Spirulina platensis, включающий исследование кинетических особенностей обезвоживания и теплотехнологических параметров распылительного способа сушки. Получены опытные партии порошков, проведен анализ дисперсионных и структурно-механических характеристик полученных порошков, показано, что процесс обезвоживания осуществляется при достаточно “мягких” термических условиях.Проведено комплекс досліджень розпилювального зневоднення біомаси Spirulina platensis, стосовно кінетичних особливостей сушіння та теплотехнологічних параметрів розпилювального способу сушки. Отримано дослідні партії порошків, проведено аналіз дисперсних та структурно-механічних характеристик отриманих порошків, виявлено, що процес зневоднення здійснюється при достатньо “м’яких” термічних умовах.A complex investigation of the spray drying of Spirulina platensis biomass have been carried out, which included studying of the kinetic properties of the dehydration process as well as the heat exchanging technological parametrs of spray drying technique. By using a pilot dryer, development types of the dry powdered product have been obtained. A analysis of the dispersion and mechanical characteristics of the powdered product being obtained has been performed. It has been shown that the drying processes has to be carried out at fairly soft dehydration regimes