Analytic structure of solutions to multiconfiguration equations

We study the regularity at the positions of the (fixed) nuclei of solutions to (non-relativistic) multiconfiguration equations (including Hartree--Fock) of Coulomb systems. We prove the following: Let {phi_1,...,phi_M} be any solution to the rank--M multiconfiguration equations for a molecule with L fixed nuclei at R_1,...,R_L in R^3. Then, for any j in {1,...,M} and k in {1,...,L}, there exists a neighbourhood U_{j,k} in R^3 of R_k, and functions phi^{(1)}_{j,k}, phi^{(2)}_{j,k}, real analytic in U_{j,k}, such that phi_j(x) = phi^{(1)}_{j,k}(x) + |x - R_k| phi^{(2)}_{j,k}(x), x in U_{j,k} A similar result holds for the corresponding electron density. The proof uses the Kustaanheimo--Stiefel transformation, as applied earlier by the authors to the study of the eigenfunctions of the Schr"odinger operator of atoms and molecules near two-particle coalescence points.Comment: 15 page

Dynamic drivers of a shallow-water hydrothermal vent ecogeochemical system (Milos, Eastern Mediterranean)

Shallow-water hydrothermal vents share many characteristics with their deep-sea analogs. However, despite ease of access, much less is known about the dynamics of these systems. Here, we report on the spatial and temporal chemical variability of a shallow-water vent system at Paleochori Bay, Milos Island, Greece, and on the bacterial and archaeal diversity of associated sandy sediments. Our multi-analyte voltammetric profiles of dissolved O2 and hydrothermal tracers (e.g. Fe2+, FeSaq, Mn2+) on sediment cores taken along a transect in hydrothermally affected sediments indicate three different areas: the central vent area (highest temperature) with a deeper penetration of oxygen into the sediment, and a lack of dissolved Fe2+ and Mn2+; a middle area (0.5 m away) rich in dissolved Fe2+ and Mn2+ (exceeding 2 mM) and high free sulfide with potential for microbial sulfide oxidation as suggested by the presence of white mats at the sediment surface; and, finally, an outer rim area (1-1.5 m away) with lower concentrations of Fe2+ and Mn2+ and higher signals of FeSaq, indicating an aged hydrothermal fluid contribution. In addition, high-frequency temperature series and continuous in situ H2S measurements with voltammetric sensors over a 6-day time period at a distance 0.5 m away from the vent center showed substantial temporal variability in temperature (32 to 46 ºC ) and total sulfide (488 to 1329 �M) in the upper sediment layer. Analysis of these data suggests that tides, winds, and abrupt geodynamic events generate intermittent mixing conditions lasting for several hours to days. Despite substantial variability, the concentration of sulfide available for chemoautotrophic microbes remained high. These findings are consistent with the predominance of Epsilonproteobacteria in the hydrothermally influenced sediments Diversity and metagenomic analyses on sediments and biofilm collected along a transect from the center to the outer rim of the vent provide further insights on the metabolic activities and the environmental factors shaping these microbial communities. Both bacterial and archaeal diversity changed along the transect as well as with sediment depth, in line with the geochemical measurements. Beside the fact that it harbors an unexpected diversity of yet undescribed bacteria and archaea, this site is also a relevant model to investigate the link between ecological and abiotic dynamics in such instable hydrothermal environments. Our results provide evidence for the importance of transient geodynamic and hydrodynamic events in the dynamics and distribution of chemoautotrophic communities in the hydrothermally influenced sediments of Paleochori Bay

Biological, socio-economic, and administrative opportunities and challenges to moving aquaculture offshore for small French oyster-farming companies

Oyster production has historically taken place in intertidal zones, and shellfish farms already occupy large extents of the French intertidal space. The expansion of French shellfish aquaculture within intertidal areas is therefore spatially limited, and moving production to the subtidal offshore environment is considered to be a possible solution to this problem. Finding new sites along the French Atlantic coast was studied here from the perspective of small oyster companies run by young farmers, who are interested in offshore bivalve aquaculture expansion compatible with their investment capacity. In assessing the feasibility of such offshore production, we considered three main issues: (1) bivalve growth potential and (2) technical feasibility and conflicting uses, both within a spatial framework, as well as (3) the steps and barriers of the administrative licensing process. Oyster spat in an experimental offshore cage showed significantly faster growth, in terms of both weight and length, compared to those in an intertidal cage, mainly due to lower turbidity and full-time feeding capacity (i.e., constant immersion in the water). A combination of Earth Observation data and bivalve ecophysiological modelling was then used to obtain spatial distribution maps of growth potential, which confirmed that offshore sites have better potential for oyster growth than the traditionally oyster-farmed intertidal sites overall, but that this is highly spatially variable. Small-scale producers indicated two technical factors constraining where farms could be located: bathymetry must be between 5 and 20 m and the distance from a harbor no more than five nautical miles. These were included along with maps of various environmental and socio-economic constraints in a Spatial Multi-Criteria Evaluation (SMCE). Touristic traffic and bottom trawling by fisherman were found to be the two other most restrictive variables. The GIS-based SMCE developed in this study showed that there is almost 400 km2 of highly- to very highly-suitable area within which to develop offshore aquaculture using simple, low-cost bottom-cage techniques, and can be used to assist the shellfish industry in the Marine Spatial Planning decision-making process, still in progress in this coastal area. However, the complexity of the administrative processes necessary to obtain an offshore license is perceived as a stronger barrier by farmers owning small companies than site selection, technical feasibility, and required investments, and will be crucial to address in order to realistically proceed to offshore cultivation. The process demonstrated here, and the results are relevant to other coastal and offshore locations throughout the world and can be adapted for other species

Pan-European Distribution of White-Nose Syndrome Fungus (Geomyces destructans) Not Associated with Mass Mortality

BACKGROUND: The dramatic mass mortalities amongst hibernating bats in Northeastern America caused by "white nose-syndrome" (WNS) continue to threaten populations of different bat species. The cold-loving fungus, Geomyces destructans, is the most likely causative agent leading to extensive destruction of the skin, particularly the wing membranes. Recent investigations in Europe confirmed the presence of the fungus G. destructans without associated mass mortality in hibernating bats in six countries but its distribution remains poorly known. METHODOLOGY/PRINCIPAL FINDINGS: We collected data on the presence of bats with white fungal growth in 12 countries in Europe between 2003 and 2010 and conducted morphological and genetic analysis to confirm the identity of the fungus as Geomyces destructans. Our results demonstrate the presence of the fungus in eight countries spanning over 2000 km from West to East and provide compelling photographic evidence for its presence in another four countries including Romania, and Turkey. Furthermore, matching prevalence data of a hibernaculum monitored over two consecutive years with data from across Europe show that the temporal occurrence of the fungus, which first becomes visible around February, peaks in March but can still be seen in some torpid bats in May or June, is strikingly similar throughout Europe. Finally, we isolated and cultured G. destructans from a cave wall adjacent to a bat with fungal growth. CONCLUSIONS/SIGNIFICANCE: G. destructans is widely found over large areas of the European continent without associated mass mortalities in bats, suggesting that the fungus is native to Europe. The characterisation of the temporal variation in G. destructans growth on bats provides reference data for studying the spatio-temporal dynamic of the fungus. Finally, the presence of G. destructans spores on cave walls suggests that hibernacula could act as passive vectors and/or reservoirs for G. destructans and therefore, might play an important role in the transmission process

The glaciers climate change initiative: Methods for creating glacier area, elevation change and velocity products

Glaciers and their changes through time are increasingly obtained from a wide range of satellite sensors. Due to the often remote location of glaciers in inaccessible and high-mountain terrain, satellite observations frequently provide the only available measurements. Furthermore, satellite data provide observations of glacier character- istics that are difficult to monitor using ground-based measurements, thus complementing the latter. In the Glaciers_cci project of the European Space Agency (ESA), three of these characteristics are investigated in detail: glacier area, elevation change and surface velocity. We use (a) data from optical sensors to derive glacier outlines, (b) digital elevation models from at least two points in time, (c) repeat altimetry for determining elevation changes, and (d) data from repeat optical and microwave sensors for calculating surface velocity. For the latter, the two sensor types provide complementary information in terms of spatio-temporal coverage. While (c) and (d) can be generated mostly automatically, (a) and (b) require the intervention of an analyst. Largely based on the results of various round robin experiments (multi-analyst benchmark studies) for each of the products, we suggest and describe the most suitable algorithms for product creation and provide recommendations concerning their practical implementation and the required post-processing. For some of the products (area, velocity) post-processing can influence product quality more than the main-processing algorithm

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

The ALICE experiment at the CERN LHC

ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 161626 m3 with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008

Etude de la combustion du charbon pulvérisé et de la biomasse sur un brûleur à swirl bas NOx

This work concerns pulverised coal combustion and coal/biomass co-firing (wood pellets) for use in large power plants. The study presents results from classical instrumentation, new experimental devices and CFD computational fluid dynamics modeling on a 3 MWth boiler equipped with a swirl low-NOx burner. The work takes place in the framework of a Franco-British European project Interreg IIIA named COSAMM. Three new tools for industry are developed at the university of Kent, an instrument to measure particle speed in the feeding pipe before the burner. Just downstream on the feeding pipe, an optical particle size measurement by imaging is made, the last instrument used is measuring flame temperature and stability. In the flame, thermocouple and species measurements are made in complement. This measurement package coupled with modeling allows the validation of new the measurement instruments. The test on the semi-industrial boiler are used for anticipating problems for upgrading to the industrial stage. The thesis presents the used fuels nature, their combustion and the theoretical bases for the combustion modeling. Moreover, the experimental setup is described. The first test campaign allows testing the experimental instruments by the measures and the modeling. The second test campaign is done on burner parameters. The last campaign biomass is added with a mass fraction input going from 0 to 20%. There is a clear decrease in unburned carbon with the increasing biomass quantity. This combustion improvement with the biomass addition is offset by a strong slagging.Ce travail présente la combustion du charbon pulvérisé et la cocombustion charbon/biomasse (pellets de bois) en vue d’une utilisation dans des foyers de grande puissance dans le cadre d’un projet Européen Interreg IIIA Franco-Britannique nommé COSAMM. L’étude présente des résultats d’instruments expérimentaux et traditionnels ainsi que de la modélisation numérique sur une chaudière équipée d’un brûleur bas-NOx à swirl de 3 MWth. Trois instruments sont à valider. Le premier sert à la mesure des particules dans la veine d’alimentation avant le brûleur. Juste en aval, une mesure optique expérimentale de la granulométrie est faite. Le dernier instrument sert à la mesure de la température de flamme et à contrôler sa stabilité. Dans la flamme, des mesures de température par thermocouple et des mesures d’espèces sont faites en complément. La thèse présente la nature des combustibles utilisés, leur combustion et les bases de la théorie de la modélisation de leur combustion. Le système expérimental et les conditions d’entrée pour les modèles sont présentés. La première campagne d’essais permet la validation des instruments avec l’appui des mesures et de la modélisation. La seconde campagne d’essais se fait sur les paramétrages du brûleur. La troisième campagne se fait sur la cocombustion, différents mélanges de charbon/biomasse sont brûlés. La modification de la flamme est significative lors du passage de la combustion du charbon pur au mélange de charbon et de 5% massique de biomasse. On observe une diminution des imbrûlés avec l’augmentation de la quantité de biomasse. Cette amélioration de la combustion avec l’ajout de biomasse est contrebalancée par l'encrassement du foyer

Quel est l'intérêt de l'ascorbémie dans le diagnostic et le traitement du scorbut ?

CAEN-BU Médecine pharmacie (141182102) / SudocSudocFranceF