pinecone/core-2020-05-10-deduplication huggingface dataset:
Encounters of the dust trails of comet 45P/Honda-Mrkos-Pajdusakova with Venus in 2006

The original publication is available in Astronomy & Astrophysics at www.aanda.org.International audienceAims. We aim to investigate the dynamical fate of meteoroids ejected during past perihelion passages of comet 45P/Honda-Mrkos-Pajdusakova that intersect the orbit of Venus. Of particular interest is the possibility, borne of previous work, that a significant flux of these particles will reach the planet during early June and late August 2006, when the Venus Express spacecraft will be operating in orbit around Venus. Methods. We have simulated the generation of meteoroid trails ejected by the comet at some past perihelion passages, and numericaly integrated them forward in time until they approach Venus in 2006. Results. On the inbound leg of the comet's path towards perihelion, we find a trail composed of dust particles ejected between 1943 and 1980 that encounters Venus on 9 June 2006 at a distance of 0.009 AU. On the outbound leg, we observe a dense trail of particles ejected between 1985 and 2001 that measures 3.4 × 10−4 AU (5 × 104 km) in half-width, and passes under the planet at a distance of 1.72 × 10−3 AU (2.6 × 105 km) on 30 August. Based on these results, we conclude that, on both occasions, the incident flux at Venus will likely be too low to allow for the detection of a shower by optical means. We discuss the circumstances under which Venus Express may encounter a significant flux of small particles detectable through impact ionization or disturbances in the interplanetary magnetic field
Edge effects on water droplet condensation

International audienceIn this study is investigated the effect of geometrical or thermal discontinuities on the growth of water droplets condensing on a cooled substrate. Edges, corners, cooled/non cooled boundaries can have a strong effect on the vapor concentration profile and mass diffusion around the drops. In comparison to growth in a pattern where droplets have to compete to catch vapor, which results in a linear water concentration profile directed perpendicularly to the substrate, droplets near discontinuities can get more vapor (outer edges, corners), resulting in faster growth or less vapor (inner edges), giving lower growth. When the cooling heat flux limits growth instead of mass diffusion (substrate with low thermal conductivity, strong heat exchange with air), edge effects can be canceled. In certain cases, growth enhancement can reach nearly 500% on edges or corners
The NAD(P)H:flavin oxidoreductase from Escherichia coli. Evidence for a new mode of binding for reduced pyridine nucleotides.

International audienceThe NAD(P)H:flavin oxidoreductase from Escherichia coli, named Fre, is a monomer of 26.2 kDa that catalyzes the reduction of free flavins using NADPH or NADH as electron donor. The enzyme does not contain any prosthetic group but accommodates both the reduced pyridine nucleotide and the flavin in a ternary complex prior to oxidoreduction. The specificity of the flavin reductase for the pyridine nucleotide was studied by steady-state kinetics using a variety of NADP analogs. Both the nicotinamide ring and the adenosine part of the substrate molecule have been found to be important for binding to the polypeptide chain. However, in the case of NADPH, the 2'-phosphate group destabilized almost completely the interaction with the adenosine moiety. Moreover, NADPH and NMNH are very good substrates for the flavin reductase, and we have shown that both these molecules bind to the enzyme almost exclusively by the nicotinamide ring. This provides evidence that the flavin reductase exhibits a unique mode for recognition of the reduced pyridine nucleotide. In addition, we have shown that the flavin reductase selectively transfers the pro-R hydrogen from the C-4 position of the nicotinamide ring and is therefore classified as an A-side-specific enzyme
Internal structures and dating of non-sulphide Zn deposits 5 using rock magnetism: insights from the Moroccan High Atlas

International audienceThe renewal of interest in Zn-Pb non-sulphide ores has been induced by mineral processing improvement and leads to new exploration and mining projects in the world. Although the mineralogy is often precisely known, and despite several studies linking ore deposition to regional tectonics, absolute dating of non-sulphide stages is rare and structure of ore bodies was largely disregarded. Geochronological data from non-sulphide ores are essential to timely constrain alteration episodes and to insert supergene ore genesis in the climate and tectonic evolution of the metallogenic province. The access to internal organization of ore could reveal post-mineralization episodes related to supergene evolution. Thus, a rock magnetism study combining anisotropy of magnetic susceptibility (AMS) and palaeomagnetism was performed on four non-sulphide deposits from the Moroccan High Atlas. AMS generally shows similar horizontal magnetic fabrics for ores and the clayey and carbonaceous internal sediments filling karstic cavities. The palaeomagnetic directions of ores and internal sediments are compatible, and the calculated poles are consistent with the last 30 Ma of the Africa apparent polar wander path, with an upper age at 0.78 Ma. The proposed three-step scenario is placed within the evolution of the Moroccan High Atlas belt. Deposition of primary sulphides is contemporaneous with opening of the Tethyan and Atlantic oceans. During the Tertiary, intracontinental deformation gave rise to the High Atlas fold-and-thrust belt and to regional uplift. Finally, Zn-Pb sulphides hosted in carbonates experienced oxidation under an arid climate to form karst-related Zn-Pb non-sulphide ores. These promising results pave the way for an efficient method to constrain the internal fabrics and age of Zn supergene deposits
Microbial mat development and dolomite formation under pre-evaporitic conditions during the Atlantic in a temperate area: The Sarliève Lake (French Massif Central)

International audienceThe Sarliève marsh in the Limagne plain, in the heart of the French Massif Central, functioned as an endorheic lake during the Late Glacial and the Early and Middle Holocene. During the Late Boreal and the Atlantic it experienced drastic lowering of the water level as a result of dry and warm climatic episodes. Then, pre-evaporitic conditions triggered the deposition of sediment rich in organic matter (OM) and in carbonates including dolomite. Fifty-one samples from a ca. 1.8 m sediment core section covering the period were analysed using Rock-Eval pyrolysis and gas chromatography-mass spectrometry (GC-MS). Throughout the interval, the OM content remained notable to high [up to 13.35% total organic carbon (TOC)] and of good quality as indicated by low oxygen index (OI) values (<200 mg CO2 g−1 TOC) and high hydrogen index (HI) values (160-660 mg HC g−1) which, as a rule, increased with increasing TOC content. In contrast to the acid fractions, which sometimes contained notable proportions of n-C16 or n-C18 fatty acids (FAs; analysed as the methyl esters, FAMEs), the neutral fractions were almost devoid of low molecular weight compounds. The latter were probably biodegraded during early diagenesis. Conversely, high molecular weight compounds were abundant in both fractions and were dominated by n-alkanols, n-alkanes, steroids and hopanoids in the neutrals and even numbered FAs and hopanoids in the acid fractions. The hopanoids were dominated by regular bishomohopanoids, accompanied by 2-methylated bishomohopanoids, as well as by unidentified bishomohopanoids with methylation in either the D or E ring. These distributions, typical for bacteria, provide support for previous hypotheses on the contribution of microorganisms to the studied record and for providing conditions for the precipitation and growth of dolomite and other pristine carbonate minerals [Bréheret, J.G., Fourmont, A., Macaire, J.J., Négrel, Ph., 2008. Microbially mediated carbonates in the Holocene lacustrine deposits of the Marais de Sarliève (French Massif Central) testify to the evolution of a restricted environment. Sedimentology 55, 557-578]. The preservation of the compounds was probably ensured by persistent reducing conditions during diagenesis, despite variable climatic conditions and related changes in lake level and sedimentation rate. Comparable distributions of hopanoic acids and hopanols, as well as roughly parallel variation with depth in the corresponding components in both fractions, strongly suggest that all the hopanoids derive from the same microbial precursors, slight shifts in the acid/alcohol ratio being governed by limited changes in redox conditions during early diagenesis
Sampling, defining, characterising and modelling the rhizosphere - The soils science toolbox

International audienceWe review methods and models that help to assess how root activity changes soil properties and affects the fluxes of matter in the soil. Subsections discuss (1) experimental systems including plant treatments in artificial media, studying the interaction of model root and microbial exudates with soil constituents, and microcosms to distinguish between soil compartments differing in root influence, (2) the sampling and characterization of rhizosphere soil and solution, focusing on the separation of soil at differentdistances from roots and the spatially resolved sampling of soil solution, (3) cutting-edge methodologies to study chemical effects in soil, including the estimation of bioavailable element or ion contents (biosensors, diffusive gradients in thin-films), studying the ultrastructure of soil components, localizing elements and determining their chemical form (microscopy, diffractometry, spectroscopy), tracing the compartmentalization of substances in soils (isotope probing, autoradiography), and imaging gradients insitu with micro electrodes or gels or filter papers containing dye indicators, (4) spectroscopic and geophysical methods to study the plants influence on the distribution of water in soils, and (5) the modeling of rhizosphere processes. Macroscopic models with a rudimentary depiction of rhizosphere processes are used to predict water or nutrient requirements by crops and forests, to estimate biogeochemical element cycles, to calculate soil water transport on a profile scale, or to simulate the development of root systems. Microscopic or explanatory models are based on mechanistic or empirical relations that describe processes on a single root or root system scale and/or chemical reactions in soil solution. We conclude that in general we have the tools at hand to assess individual processes on the microscale under rather artificial conditions. Microscopic, spectroscopic and tracer methods to look at processes in small “aliquots” of naturally structured soil seem to step out of their infancy and have become promising tools to better understand the complex interactions between plant roots, soil and microorganisms. On the field scale, while there are promising first results on using non-invasive geophysical methods to assess the plant's influence on soil moisture, there are no such tools in the pipeline to assess the spatial heterogeneity of chemical properties and processes in the field. Here, macroscopic models have to be used, or model results on the microscopic level have to be scaled up to the whole plant or plot scale. Upscaling is recognized as a major challenge
Zinc isotopes in HEDs: clues to the formation of 4-Vesta, and the unique composition of Pecora Escarpment 82502

International audienceThe δ66Zn (permil deviation of the 66Zn/64Zn ratio from a terrestrial standard) values for a suite of 20 non-Antarctic HED (howardite - eucrite - diogenite) meteorites and one mesosiderite, and for 8 Antarctic eucrites and diogenites, were measured in order to determine the role of volatization in the formation of their presumed parent body, the asteroid 4-Vesta. The 20 non-Antarctic HEDs had δ66Zn values that ranged from -2.0 ‰ to +1.67 ‰, with a mean value of -0.01 ± 0.39 ‰ (2se); this range likely represents a small-scale heterogeneity due to brecciation induced by multiple impacts. The non-Antarctic eucrites (δ66Zn = +0.00 ± 0.58 ‰ (2se), n=12) were isotopically the same as the diogenites (δ66Zn = -0.31 ± 0.80 ‰ (2se), n=4), and the howardites (δ66Zn = +0.26 ± 0.37 ‰ (2se), n=4). On average, non-Antarctic eucrite falls were isotopically heavier (+0.50 ‰) than non-Antarctic finds (-1.00 ‰). The Antarctic finds studied were all unbrecciated samples, and they were significantly heavier than the non-Antarctic samples with a δ66Zn range of +1.63 to +6.22‰ for 4 eucrites (mean, +4.32‰) and +0.94 to +1.60‰ for 3 diogenites (mean +1.23‰), excluding one anomalous sample, while their Zn concentration is significantly lower than the brecciated samples. These data suggest that the unbrecciated eucrites probably represent the eucritic crust shortly after differentiation and cooling of the parent asteroid, at which time volatization of lighter zinc isotopes led to an isotopically heavy crust. Early impact events caused the ejection of these unbrecciated meteorites, which were subsequently spared from brecciation caused by multiple additional impacts on the much larger Vesta. The range of δ66Zn values and Zn concentration for the brecciated HEDs in this study supports a major contribution to the Vestan surface by chondritic impactors (-1.30 < δ66Zn < +0.76 ‰ for ordinary and carbonaceous chondrites). The anomalous eucrite PCA 82502 (δ66Zn= -7.75 ‰) is significantly isotopically lighter than the other HEDs and is the natural sample with the lightest Zn isotopic composition reported in the solar system to date. This meteorite most likely originated from a distinct parent body
Balneola alkaliphila sp. nov., a marine bacterium isolated from the Mediterranean Sea

En libre-accès sur Archimer : http://archimer.ifremer.fr/doc/2008/publication-5292.pdfInternational audienceA novel aerobic, Gram-negative bacterium, designated strain CM41_14b(T), was isolated from surface waters in the coastal north-western Mediterranean Sea. Cells were non-motile, straight rods, 2.6 microm long and 0.7 microm wide and formed pale-orange colonies on marine agar medium. The G+C content of the genomic DNA was 39 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence placed the strain within the genus Balneola (phylum Bacteroidetes). On the basis of 16S rRNA gene sequence comparisons, and physiological and biochemical characteristics, the isolate represents a novel species for which the name Balneola alkaliphila sp. nov. is proposed. The type strain is CM41_14b(T) (=DSM 19538(T)=CIP 109603(T)=OOB 103(T))
Nonlinear Donati compatibility conditions and the intrinsic approach for nonlinearly elastic plates

Linear Donati compatibility conditions guarantee that the components of symmetric tensor fields are those of linearized change of metric or linearized change of curvature tensor fields associated with the displacement vector field arising in a linearly elastic structure when it is subjected to applied forces. These compatibility conditions take the form of variational equations with divergence-free tensor fields as test-functions, by contrast with Saint-Venant compatibility conditions, which take the form of systems of partial differential equations. In this paper, we identify and justify nonlinear Donati compatibility conditions that apply to a nonlinearly elastic plate modeled by the Kirchhoff-von K'arm'an-Love theory. These conditions, which to the authors' best knowledge constitute a first example of nonlinear Donati compatibility conditions, in turn allow to recast the classical approach to this nonlinear plate theory, where the unknown is the position of the deformed middle surface of the plate, into the intrinsic approach, where the change of metric and change of curvature tensor fields of the deformed middle surface of the plate are the only unknowns. The intrinsic approach thus provides a direct way to compute the stress resultants and the stress couples inside the deformed plate, often the unknowns of major interest in computational mechanics
Assault frequency and preformation probability of the alpha emission process

A study of the assault frequency and preformation factor of the α-decay description is performed from the experimental α-decay constant and the penetration probabilities calculated from the generalized liquid-drop model (GLDM) potential barriers. To determine the assault frequency a quantum-mechanical method using a harmonic oscillator is introduced and leads to values of around 1021 s−1, similar to the ones calculated within the classical method. The preformation probability is around 10−1-10−2. The results for even-even Po isotopes are discussed for illustration. While the assault frequency presents only a shallow minimum in the vicinity of the magic neutron number 126, the preformation factor and mainly the penetrability probability diminish strongly around N=126
Synthesis and characterization of palladacyclopentadiene complexes with N-heterocyclic carbene ligands

New palladacyclopentadiene compounds containing different chelate NHC-thioether and NHC-pyridine\ud
ligands have been prepared by transfer of the functionalized carbenes from the respective silver complexes\ud
to the polymeric precursors [PdC-COOR)4]n (R = Me, t-Bu). Their dynamic behaviour in solution\ud
was discussed and the solid-structure of 2c was determined by X-ray crystallography.\ud
The treatment of [Pd(C-COOCH3)4]n with two equivalents of the carbene silver complexes led to the\ud
(NHC)2Pd(C4-COOCH3)4 derivatives (3cei), a new class of compounds with only PdeC bonds. A serious\ud
limitation to this synthetic procedure is an excessive steric crowding around the metal centre.\ud
The complexes 3 are present in solution as a mixture of two atropoisomers, due to restricted rotation\ud
around the CarbeneePd bond. The kinetics of equilibration between the two configurational isomers was\ud
studied for complex 3c, which was also structurally defined by X-ray crystallography (anti isomer).\ud
Finally a synthetic protocol was set up for the synthesis of mixed NHC-Phosphine and NHC-Isocyanide\ud
palladacyclopentadiene complexes. In this procedure the order of addition of the reactants is of great\ud
importanc
Modulation of different clusterin isoforms in human colon tumorigenesis

Clusterin is a ubiquitous secretory heterodimeric disulfide-linked glycoprotein, which is implicated in several physiological processes, including immune regulation, cell adhesion and morphological transformation, lipid transportation, tissue remodelling, membrane recycling and cell-cell interactions. A large number of studies have focused their interest on clusterin gene products as mediators of cell cycle progression and cell death induction, although data on the different isoforms and their role in the different cell processes are still obscure. Recently, an increased clusterin expression in breast cancer has been reported. In order to elucidate the role of clusterin in tumor progression and whether one of its isoforms is preferentially expressed in tumorigenesis, we examined its presence throughout the different steps of human colon carcinoma, one of the best-characterized models of human tumor progression. The immunohistochemical observation of 30 bioptic and surgical colon specimens demonstrated a cell compartment clusterin translocation from the nucleus to the cytoplasm directly related to tumor progression. In fact, a nuclear localization found in healthy colonic mucosa is consistent with the involvement of the proapoptotic nuclear form in the regulation of cell cycle progression and in cell death induction. The progression towards high-grade and metastatic carcinoma leads to cytoplasmic clusterin distribution. Protein extracts from freshly isolated cells of the same patients confirm in high-grade carcinomas with metastatic nodes the complete loss of the proapoptotic nuclear form and a cytoplasmic overexpression of the highly glycosylated form. Data obtained from in vitro experiments confirm that this form is released in the extracellular space and corresponded to the fully glycosylated one. These data suggest that the controversial data on clusterin function in tumors may be related to the pattern shift of its isoform production. As the secreted form of clusterin is correlated to cell matrix formation, cell membrane remodeling and cell-cell adhesion, the overexpression of this form in highly aggressive tumors and metastatic nodes could be a potential new prognostic and predictive marker for colon carcinoma aggressiveness
Betaproteobacteria dominance and diversity shifts in the bacterial community of a PAH-contaminated soil exposed to phenanthrene.

International audienceIn this study, the PAH-degrading bacteria of a constructed wetland collecting road runoff has been studied through DNA stable isotope probing. Microcosms were spiked with (13)C-phenanthrene at 34 or 337 ppm, and bacterial diversity was monitored over a 14-day period. At 337 ppm, PAH degraders became dominated after 5 days by Betaproteobacteria, including novel Acidovorax, Rhodoferax and Hydrogenophaga members, and unknown bacteria related to Rhodocyclaceae. The prevalence of Betaproteobacteria was further demonstrated by phylum-specific quantitative PCR, and was correlated with a burst of phenanthrene mineralization. Striking shifts in the population of degraders were observed after most of the phenanthrene had been removed. Soil exposed to 34 ppm phenanthrene showed a similar population of degraders, albeit only after 14 days. Results demonstrate that specific Betaproteobacteria are involved in the main response to soil PAH contamination, and illustrate the potential of SIP approaches to investigate PAH biodegradation in soil
Effects of deficit irrigation strategies on soil salinization and sodification in a semiarid drip-irrigated peach orchard

Deficit irrigation strategies save water, but may enhance soil salinization and sodification when irrigated with low-quality waters. The objectives of this five-year study performed in the middle Ebro Basin (Spain) were to quantify these processes and assess their potential deleterious impact on the response of peach trees subjected to full irrigation (FULL), sustained deficit irrigation (SDI, irrigated at 62.5% of FULL) and regulated deficit irrigation (RDI, irrigated at 50% of FULL in Stage II of fruit development). In relation to FULL, water savings were 40% in SDI and 9% in RDI. Soil salinity (ECe), chloride concentration (Cle) and sodicity (SARe) measured in the saturation extract of 480 soil samples generally increased in the irrigation seasons, particularly in the more severe deficit irrigation strategy (SDI). These increases were counteracted by the leaching of salts induced by high leaching fractions (LF) and low water deficits (WD) attained during the non irrigation seasons. The changes in ECe, Cle and SARe measured between sampling dates were significantly correlated (p < 0.01) with WD and LF calculated for the periods between sampling dates. These parameters were therefore suitable to estimate the required irrigation depths for soil salinity and sodicity control. Peach trees were unaffected by the irrigation treatments, but yield productivity tended to decline above a threshold ECe of 4 dS m−1. Under the irrigation salinity (mean EC = 1.1 dS m−1) and the semiarid climatic characteristics of the study area, the three examined irrigation strategies proved to be sustainable in the five studied year