188 research outputs found
Les poissons amphihalins de France face au changement climatique : évolution des effectifs et modification de la phénologie migratoire
Les poissons amphihalins sont en dĂ©clin en France et dans le monde. Vivant alternativement en eau douce et en eau salĂ©e, ils sont confrontĂ©s Ă de nombreuses pressions auxquelles sâajoute celle du changement climatique, qui entraĂźne principalement 3 grandes modifications : (i) changement de lâaire de distribution des espĂšces, (ii) modification du calendrier des moments clĂ© des cycles de vie, et (iii) modification du synchronisme spatial des populations. EspĂšces emblĂ©matiques de nos cours dâeau et Ă forte valeur Ă©conomique, les poissons amphihalins font lâobjet de plan de gestion partout en France, la plupart du temps Ă lâĂ©chelle des bassins-versants, avec peu de mise en perspective sur lâĂ©tat de ces populations Ă lâĂ©chelle française. Lâobjectif de ce travail est de contribuer Ă combler ce manque en analysant des donnĂ©es collectĂ©es dans tous les bassins-versants français mais qui nâavaient jamais Ă©tĂ© mises en commun ni valorisĂ©es Ă cette Ă©chelle. Jâai bancarisĂ© les donnĂ©es de 46 stations de comptage ayant un historique dâau moins 10 annĂ©es et portant sur 5 taxons amphihalins : Alosa spp. (regroupant Alosa fallax et Alosa alosa), Anguilla anguilla, Petromyzon marinus, Salmo salar et Salmo trutta. BasĂ©es sur ce jeu de donnĂ©es, nous avons posĂ© 3 questions : (i) comment les comptages des poissons amphihalins ont-ils Ă©voluĂ© en France ces 30 derniĂšres annĂ©es, (ii) ces taxons ont-ils modifiĂ© leur calendrier de migration au cours de cette pĂ©riode dâĂ©tude, et quels en sont les paramĂštres explicatifs, et (iii) observe-t-on un synchronisme spatial dans les dynamiques et dans les calendriers de migration de ces populations, et quels en sont les paramĂštres explicatifs. Nous montrons que lâĂ©volution des comptages est contrastĂ©e entre les taxons et les bassinsversants, avec des taxons en diminution Ă lâĂ©chelle française (Alosa spp. et Petromyzon marinus) tandis que dâautres sont en augmentation lĂ©gĂšre ou en stagnation. Alosa spp. est Ă la fois le taxon montrant la plus forte diminution de ses comptages Ă lâĂ©chelle française et la plus grande homogĂ©nĂ©itĂ© entre les stations, attestant dâun dĂ©clin assez gĂ©nĂ©ralisĂ© en France. Lâanalyse des calendriers de migration a permis de mettre en Ă©vidence une avancĂ©e globale des dates mĂ©dianes de migration de lâensemble des taxons, exceptĂ© les civelles, dâen moyenne -2,3 jours par dĂ©cennie (min = -0,2 ; max = -3,7). Alosa spp. est le taxon montrant lâavancĂ©e la plus importante. Lâensemble des paramĂštres environnementaux testĂ©s influence les migrations, attestant de lâimportance de considĂ©rer ces paramĂštres Ă diffĂ©rentes Ă©chelles. Enfin, nous montrons que le synchronisme de ces taxons reste modĂ©rĂ© Ă lâĂ©chelle nationale et quâil est toujours plus fort Ă lâĂ©chelle des bassins-versants. Parmi les taxons Ă©tudiĂ©s, Alosa spp. est celui ayant le plus fort synchronisme des effectifs, quelle que soit lâĂ©chelle considĂ©rĂ©e. Ces rĂ©sultats contribuent Ă lâapport de connaissances nĂ©cessaires Ă la prise de dĂ©cisions pour gĂ©rer le plus efficacement possible ces populations. En particulier, jâai pu mettre en Ă©vidence que : âą LâĂ©tat des populations doit ĂȘtre analysĂ© en prenant en compte des sources de donnĂ©es diffĂ©rentes. âą Le contexte actuel de changement climatique nĂ©cessite de limiter au maximum les sĂ©lections anthropiques afin de favoriser lâadaptation et la rĂ©silience des populations, que ce soit (i) lors de la migration lorsque des ouvrages sont prĂ©sents, (ii) dans le suivi des pĂȘcheries y compris lorsquâelles font lâobjet de mesures de limitation de la pĂȘche, ou (iii) dans les programmes de soutien en effectif, et ce sur lâensemble de la filiĂšre allant de la capture au dĂ©versement. Suite Ă ces rĂ©sultats, plusieurs perspectives Ă©mergent dont un travail plus prĂ©cis sur la dĂ©finition des paramĂštres de gestion Ă lâintĂ©rieur des bassins-versants, lâanalyse de ces donnĂ©es Ă lâĂ©chelle de lâaire de rĂ©partition des taxons, et lâutilisation des scĂ©narii du GIEC afin dâestimer les modifications attendues Ă la fin du siĂšcle
Numerical Simulation of Tool/Abradable Material Interaction Experiments
International audienceApplying abradable coating on the casing of turbomachines has been widely recognized as a robust solution advantageously combining the adjustment of operating clearances with the reduction of potential non-repairable damages. Thus, the modeling of this material is a growing field of investigation. Based on the numerical strategy proposed and detailed in previous publication by the same authors, the present study aims at capturing the mechanical behavior of abradable coating in the context of high speed interaction with a rigid tool. The plastic law given is first enriched in order to take into account strain rate dependence. The sensitivity of the model regarding its main numerical parameters is assessed and highlights the role of each of these parameters. The calibration of numerical results with respect to experimental results lead to very satisfying results that confirm that the proposed strategy is well-suited for the modeling of abradable coating. Finally, the newly developped viscoplastic law is applied to a 3D rotor/stator interaction case to determine the criticity of strain rate dependence in the case of blade/casing contact
Genetic control of plasticity of oil yield for combined abiotic stresses using a joint approach of crop modeling and genome-wide association
Understanding the genetic basis of phenotypic plasticity is crucial for
predicting and managing climate change effects on wild plants and crops. Here,
we combined crop modeling and quantitative genetics to study the genetic
control of oil yield plasticity for multiple abiotic stresses in sunflower.
First we developed stress indicators to characterize 14 environments for
three abiotic stresses (cold, drought and nitrogen) using the SUNFLO crop model
and phenotypic variations of three commercial varieties. The computed plant
stress indicators better explain yield variation than descriptors at the
climatic or crop levels. In those environments, we observed oil yield of 317
sunflower hybrids and regressed it with three selected stress indicators. The
slopes of cold stress norm reaction were used as plasticity phenotypes in the
following genome-wide association study.
Among the 65,534 tested SNP, we identified nine QTL controlling oil yield
plasticity to cold stress. Associated SNP are localized in genes previously
shown to be involved in cold stress responses: oligopeptide transporters, LTP,
cystatin, alternative oxidase, or root development. This novel approach opens
new perspectives to identify genomic regions involved in
genotype-by-environment interaction of a complex traits to multiple stresses in
realistic natural or agronomical conditions.Comment: 12 pages, 5 figures, Plant, Cell and Environmen
Recommended from our members
Session E9: Cumulated Mortalities of Salmon and Eel in the Turbines of the Loire-Brittany District
Abstract:
The effect of dams on mortality during downstream migration was simulated using distribution and mortality models in the whole Loire-Brittany water district (155 000 Km2). A combination of models was used: (1) juvenile habitats for smolts, (2) productivity of juvenile salmon habitats, (3) production of silver eels (EDA model), The models (1)*(2) and (3) were used to predict the number of downstream migrants in the current conditions and with a transparent upstream migration. (4) Turbine mortality was calculated from either the characteristics of the turbine (diameter, rotation speed, height ...) or by extrapolation from the average mortality when information was missing to run the model. (5) Mortalities at the dam level were then derived from the nominal flow of each turbine and from the flow of the spill under 5 flow scenarios. A similar overall production of about 100 000 smolts per year was found in the Loire and Britany and the current production of eels was evaluated at 306 700, 314 900 and 124 400 silver eels for Brittany, the Loire and Vendée coastal streams respectively. The average mortality calculated at 387 dams and 578 turbines was estimated at 16.9% in Kaplan, 19.6% in Francis turbines, for smolts, and 45.8% and 88.5% for eels.
For salmon, the number of kills was evaluated as N=26 900 (ie 27% of the Loireâs smolt production), and N=1 636 (ie 2%) in Brittany. For eel, the number of kills was evaluated as N=9 800 (ie 3.1%) of the silver eel production in the Loire, N=9 400 (ie 3.3%) in Brittany and N=2 700 (ie 2.2%) in VendĂ©e. The results will allow to prioritize actions and provide a first estimate of the level of mortality affecting eel and salmon in the Loire-Britany basin
Emission State Structure and Linewidth Broadening Mechanisms in Type-II CdSe/CdTe CoreâCrown Nanoplatelets: A Combined TheoreticalâSingle Nanocrystal Optical Study
Type-II heterostructures are key elementary components in optoelectronic, photovoltaic, and quantum devices. The staggered band alignment of materials leads to the stabilization of indirect excitons (IXs), i.e., correlated electronâhole pairs experiencing spatial separation with novel properties, boosting optical gain and promoting strategies for the design of information storage, charge separation, or qubit manipulation devices. Planar colloidal CdSe/CdTe coreâcrown type-II nested structures, grown as nanoplatelets (NPLs), are the focus of the present work. By combining low temperature single NPL measurements and electronic structure calculations, we gain insights into the mechanisms impacting the emission properties. We are able to probe the sensitivity of the elementary excitations (IXs, trions) with respect to the appropriate structural parameter (core size). Neutral IXs, with binding energies reaching 50 meV, are shown to dominate the highly structured single NPL emission. The large broadening linewidth that persists at the single NPL level clearly results from strong excitonâLO phonon coupling (Eph = 21 meV) whose strength is poorly influenced by trapped charges. The spectral jumps (â10 meV) in the photoluminescence recorded as a function of time are explained by the fluctuations in the IX electrostatic environment considering fractional variations (â0.2 e) of the noncompensated charge defects
Genetic landscape of a large cohort of Primary Ovarian Insufficiency : New genes and pathways and implications for personalized medicine
Background Primary Ovarian Insufficiency (POI), a public health problem, affects 1-3.7% of women under 40 yield-ing infertility and a shorter lifespan. Most causes are unknown. Recently, genetic causes were identified, mostly in single families. We studied an unprecedented large cohort of POI to unravel its molecular pathophysiology.Methods 375 patients with 70 families were studied using targeted (88 genes) or whole exome sequencing with pathogenic/likely-pathogenic variant selection. Mitomycin-induced chromosome breakages were studied in patients' lymphocytes if necessary. Findings A high-yield of 29.3% supports a clinical genetic diagnosis of POI. In addition, we found strong evidence of pathogenicity for nine genes not previously related to a Mendelian phenotype or POI: ELAVL2, NLRP11, CENPE, SPATA33, CCDC150, CCDC185, including DNA repair genes: C17orf53(HROB), HELQ, SWI5 yielding high chromo-somal fragility. We confirmed the causal role of BRCA2, FANCM, BNC1, ERCC6, MSH4, BMPR1A, BMPR1B, BMPR2, ESR2, CAV1, SPIDR, RCBTB1 and ATG7 previously reported in isolated patients/families. In 8.5% of cases, POI is the only symptom of a multi-organ genetic disease. New pathways were identified: NF-kB, post-translational regulation, and mitophagy (mitochondrial autophagy), providing future therapeutic targets. Three new genes have been shown to affect the age of natural menopause supporting a genetic link.Interpretation We have developed high-performance genetic diagnostic of POI, dissecting the molecular pathogene-sis of POI and enabling personalized medicine to i) prevent/cure comorbidities for tumour/cancer susceptibility genes that could affect life-expectancy (37.4% of cases), or for genetically-revealed syndromic POI (8.5% of cases), ii) predict residual ovarian reserve (60.5% of cases). Genetic diagnosis could help to identify patients who may benefit from the promising in vitro activation-IVA technique in the near future, greatly improving its success in treating infertility.Funding Universite? Paris Saclay, Agence Nationale de Biome?decine.Copyright (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)Peer reviewe
Medulloblastomas with ELP1 pathogenic variants: A weakly penetrant syndrome with a restricted spectrum in a limited age window
Background: ELP1 pathogenic variants (PV) have been recently identified as the most frequent variants predisposing to Sonic Hedgehog (SHH) medulloblastomas (MB); however, guidelines are still lacking for genetic counseling in this new syndrome. Methods: We retrospectively reviewed clinical and genetic data of a French series of 29 ELP1-mutated MB. Results: All patients developed SHH-MB, with a biallelic inactivation of PTCH1 found in 24 tumors. Other recurrent alterations encompassed the TP53 pathway and activation of MYCN/MYCL signaling. The median age at diagnosis was 7.3 years (range: 3-14). ELP1-mutated MB behave as sporadic cases, with similar distribution within clinical and molecular risk groups and similar outcomes (5 y - OS=86%); no unusual side effect of treatments was noticed. Remarkably, a germline ELP1 PV was identified in all patients with available constitutional DNA (n=26); moreover, all tested familial trio (n=11) revealed that the PVs were inherited. Two of the 26 index cases from the French series had a family history of MB; pedigrees from these patients and from 1 additional Dutch family suggested a weak penetrance. Apart from MB, no cancer was associated with ELP1 PVs; second tumors reported in 4 patients occurred within the irradiation fields, in the usual time-lapse for expected radiotherapy-induced neoplasms. Conclusions: The low penetrance, the "at risk' age window limited to childhood and the narrow tumor spectrum, question the actual benefit of genetic screening in these patients and their family. Our results suggest restricting ELP1 germline sequencing to patients with SHH-MB, depending on the parents"request
The FANCM:p.Arg658* truncating variant is associated with risk of triple-negative breast cancer
Abstract: Breast cancer is a common disease partially caused by genetic risk factors. Germline pathogenic variants in DNA repair genes BRCA1, BRCA2, PALB2, ATM, and CHEK2 are associated with breast cancer risk. FANCM, which encodes for a DNA translocase, has been proposed as a breast cancer predisposition gene, with greater effects for the ER-negative and triple-negative breast cancer (TNBC) subtypes. We tested the three recurrent protein-truncating variants FANCM:p.Arg658*, p.Gln1701*, and p.Arg1931* for association with breast cancer risk in 67,112 cases, 53,766 controls, and 26,662 carriers of pathogenic variants of BRCA1 or BRCA2. These three variants were also studied functionally by measuring survival and chromosome fragility in FANCMâ/â patient-derived immortalized fibroblasts treated with diepoxybutane or olaparib. We observed that FANCM:p.Arg658* was associated with increased risk of ER-negative disease and TNBC (OR = 2.44, P = 0.034 and OR = 3.79; P = 0.009, respectively). In a country-restricted analysis, we confirmed the associations detected for FANCM:p.Arg658* and found that also FANCM:p.Arg1931* was associated with ER-negative breast cancer risk (OR = 1.96; P = 0.006). The functional results indicated that all three variants were deleterious affecting cell survival and chromosome stability with FANCM:p.Arg658* causing more severe phenotypes. In conclusion, we confirmed that the two rare FANCM deleterious variants p.Arg658* and p.Arg1931* are risk factors for ER-negative and TNBC subtypes. Overall our data suggest that the effect of truncating variants on breast cancer risk may depend on their position in the gene. Cell sensitivity to olaparib exposure, identifies a possible therapeutic option to treat FANCM-associated tumors
- âŠ