155 research outputs found

    Chagall: L'ascension des thèmes et des couleurs

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    Suelos volcanicos endurecidos

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    The agricultural rehabilitation of tepetates, indurated and sterile volcanic tuffs located along the mexican neovolcanic ridge, is technically possible. However, it is necessary to know in detail the agro-socioeconomical factors of the peasant communities which have these kind of lands, to give them technical answers appropiate to local realities. The studies of 4 communities located in the states of Mexico. Tlaxcala, Jalisco and Michoacan, show that the climatic conditions are mostly difficult (long dry season, irregular rains, early frosts). The use of irrigation is limited. Each producer family cultivates a small surface of land which is principally ejidal. Tepetates areas are the last pieces of land still not distributed and of common use (firewood ans pasture).Most peasants can survive with the help of an external job, while field production is mainly for self-consumption. During the last 20 years, capitalisation occured through the purchase of cattle. So, the number of animals is growing up and by consequence, the pressure on the natural pastures too, favouring the apparition and extension of tepetates. Breaking the tepetates to give them a new agricultural use means, in addition to technical help at the beginning, the creation and development of forage crops. Actually, this type of crops are not very common. It is also necessary to propose forest management and/or wood-fire plantations. The costs of this rehabilitation are too high (nearly 1,000 $/ha) for most peasants, in spite of the increasing value of the land after this work and a recuperation of the investment after 5 and 8 years in the production systems which use animal and mechanical tractions. So those investments require external help (State, NGOs, credits...) at the beginning. (Résumé d'auteur)

    Interaction of quasilocal harmonic modes and boson peak in glasses

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    The direct proportionality relation between the boson peak maximum in glasses, ωb\omega_b, and the Ioffe-Regel crossover frequency for phonons, ωd\omega_d, is established. For several investigated materials ωb=(1.5±0.1)ωd\omega_b = (1.5\pm 0.1)\omega_d. At the frequency ωd\omega_d the mean free path of the phonons ll becomes equal to their wavelength because of strong resonant scattering on quasilocal harmonic oscillators. Above this frequency phonons cease to exist. We prove that the established correlation between ωb\omega_b and ωd\omega_d holds in the general case and is a direct consequence of bilinear coupling of quasilocal oscillators with the strain field.Comment: RevTex, 4 pages, 1 figur

    Sustained IFN signaling is associated with delayed development of SARS-CoV-2-specific immunity.

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    Plasma RNAemia, delayed antibody responses and inflammation predict COVID-19 outcomes, but the mechanisms underlying these immunovirological patterns are poorly understood. We profile 782 longitudinal plasma samples from 318 hospitalized patients with COVID-19. Integrated analysis using k-means reveals four patient clusters in a discovery cohort: mechanically ventilated critically-ill cases are subdivided into good prognosis and high-fatality clusters (reproduced in a validation cohort), while non-critical survivors segregate into high and low early antibody responders. Only the high-fatality cluster is enriched for transcriptomic signatures associated with COVID-19 severity, and each cluster has distinct RBD-specific antibody elicitation kinetics. Both critical and non-critical clusters with delayed antibody responses exhibit sustained IFN signatures, which negatively correlate with contemporaneous RBD-specific IgG levels and absolute SARS-CoV-2-specific B and CD4 <sup>+</sup> T cell frequencies. These data suggest that the "Interferon paradox" previously described in murine LCMV models is operative in COVID-19, with excessive IFN signaling delaying development of adaptive virus-specific immunity

    Construction, assembly and tests of the ATLAS electromagnetic end-cap calorimeters

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    The construction and the assembly of the two end-caps of the ATLAS liquid argon electromagnetic calorimeter as well as their test and qualification programs are described. The work described here started at the beginning of 2001 and lasted for approximately three years. The results of the qualification tests performed before installation in the LHC ATLAS pit are given. The detectors are now installed in the ATLAS cavern, full of liquid argon and being commissioned. The complete detectors coverage is powered with high voltage and readout

    DES Y3 + KiDS-1000: Consistent cosmology combining cosmic shear surveys

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    We present a joint cosmic shear analysis of the Dark Energy Survey (DES Y3) and the Kilo-Degree Survey (KiDS-1000) in a collaborative effort between the two survey teams. We find consistent cosmological parameter constraints between DES Y3 and KiDS-1000 which, when combined in a joint-survey analysis, constrain the parameter S8=σ8Ωm/0.3S_8 = \sigma_8 \sqrt{\Omega_{\rm m}/0.3} with a mean value of 0.7900.014+0.0180.790^{+0.018}_{-0.014}. The mean marginal is lower than the maximum a posteriori estimate, S8=0.801S_8=0.801, owing to skewness in the marginal distribution and projection effects in the multi-dimensional parameter space. Our results are consistent with S8S_8 constraints from observations of the cosmic microwave background by Planck, with agreement at the 1.7σ1.7\sigma level. We use a Hybrid analysis pipeline, defined from a mock survey study quantifying the impact of the different analysis choices originally adopted by each survey team. We review intrinsic alignment models, baryon feedback mitigation strategies, priors, samplers and models of the non-linear matter power spectrum.Comment: 38 pages, 21 figures, 15 tables, submitted to the Open Journal of Astrophysics. Watch the core team discuss this analysis at https://cosmologytalks.com/2023/05/26/des-kid

    Fine-Scale Mapping of the 4q24 Locus Identifies Two Independent Loci Associated with Breast Cancer Risk

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    Background: A recent association study identified a common variant (rs9790517) at 4q24 to be associated with breast cancer risk. Independent association signals and potential functional variants in this locus have not been explored. Methods: We conducted a fine-mapping analysis in 55,540 breast cancer cases and 51,168 controls from the Breast Cancer Association Consortium. Results: Conditional analyses identified two independent association signals among women of European ancestry, represented by rs9790517 [conditional P = 2.51 × 10−4; OR, 1.04; 95% confidence interval (CI), 1.02–1.07] and rs77928427 (P = 1.86 × 10−4; OR, 1.04; 95% CI, 1.02–1.07). Functional annotation using data from the Encyclopedia of DNA Elements (ENCODE) project revealed two putative functional variants, rs62331150 and rs73838678 in linkage disequilibrium (LD) with rs9790517 (r2 ≥ 0.90) residing in the active promoter or enhancer, respectively, of the nearest gene, TET2. Both variants are located in DNase I hypersensitivity and transcription factor–binding sites. Using data from both The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), we showed that rs62331150 was associated with level of expression of TET2 in breast normal and tumor tissue. Conclusion: Our study identified two independent association signals at 4q24 in relation to breast cancer risk and suggested that observed association in this locus may be mediated through the regulation of TET2. Impact: Fine-mapping study with large sample size warranted for identification of independent loci for breast cancer risk

    The European Virus Archive goes global: A growing resource for research

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    The European Virus Archive (EVA) was created in 2008 with funding from the FP7-EU Infrastructure Programme, in response to the need for a coordinated and readily accessible collection of viruses that could be made available to academia, public health organisations and industry. Within three years, it developed from a consortium of nine European laboratories to encompass associated partners in Africa, Russia, China, Turkey, Germany and Italy. In 2014, the H2020 Research and Innovation Framework Programme (INFRAS projects) provided support for the transformation of the EVA from a European to a global organization (EVAg). The EVAg now operates as a non-profit consortium, with 26 partners and 20 associated partners from 21 EU and non-EU countries. In this paper, we outline the structure, management and goals of the EVAg, to bring to the attention of researchers the wealth of products it can provide and to illustrate how end-users can gain access to these resources. Organisations or individuals who would like to be considered as contributors are invited to contact the EVAg coordinator, Jean-Louis Romette, at [email protected]
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