307 research outputs found

    Rapport de prospection et sondages, Larrau, Pyrénées-Atlantiques. Campagne 2014

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    Nichée au pied du pic d’Orhy (2017 m), point culminant de la vallée, Larrau est la dernière commune de haute Soule avant la frontière espagnole. Elle constitue le terrain d’études d’abord plutôt géographiques qui ont lentement évolué vers des aspects plus anthropologiques, historiques et archéologiques. A la suite du développement des recherches archéologiques sur les dynamiques des systèmes pastoraux d'altitude pyrénéens, deux programmes de prospections ont été menés en 2012 et 2013 sur une partie du territoire de cette immense commune (12 500 ha). Les sites pastoraux d’altitude du pays basque étaient très mal connus. Ces deux premières campagnes de prospection ont permis de recenser 99 structures, dont 38 cabanes, 17 enclos et 41 tertres, répartis en 45 sites.En 2014, pour mieux les connaître et les caractériser, une approche interdisciplinaire combinant sources écrites, sondages archéologiques et prospections non invasives a été entreprise. Ainsi, plusieurs fonds d’archives de familles paysannes, couvrant principalement les années 1750-1850, permettent d’identifier 17 cayolars antérieurs à la constitution du cadastre dit napoléonien qui en mentionne 70. En parallèle, une équipe américaine de l’université de Géorgie à Athens (UGA) a testé des carottages à la tarière et des prospections radar dans et autour de quelques sites. L’objectif est d’identifier, de caractériser ces sites de manière non destructrice et aussi de reconnaître des sols anciens pour les analyser. Enfin, la collaboration a consisté en une approche archéologique commune sur deux sites (Ibarrondua et Antchulogia), regroupant quatre structures. Les sondages, de 2 à 3 m², ont été positionnés de façon à couvrir le mur sur un mètre carré et l’intérieur de la structure sur le mètre carré restant. A Ibarrondua, deux cabanes rectangulaires ont été identifiées et datées des XVe siècle (st. 125), et XVe-XVIIe siècles (st. 124), à proximité d’un enclos très arasé, mais visiblement contemporain. Sur le second site, des niveaux du XVe siècle ont été repéré sous un mur contemporain, et une stratigraphie calée entre le XI-XIIIe et le XIVe-XVe siècle. Cette première campagne de fouilles, prometteuse, a laissé percevoir l’intensité de l’occupation médiévale, dont les traces matérielles étaient jusqu’alors inconnues

    PINT: A Modern Software Package for Pulsar Timing

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    Over the past few decades, the measurement precision of some pulsar-timing experiments has advanced from ~10 us to ~10 ns, revealing many subtle phenomena. Such high precision demands both careful data handling and sophisticated timing models to avoid systematic error. To achieve these goals, we present PINT (PINT Is Not Tempo3), a high-precision Python pulsar timing data analysis package, which is hosted on GitHub and available on Python Package Index (PyPI) as pint-pulsar. PINT is well-tested, validated, object-oriented, and modular, enabling interactive data analysis and providing an extensible and flexible development platform for timing applications. It utilizes well-debugged public Python packages (e.g., the NumPy and Astropy libraries) and modern software development schemes (e.g., version control and efficient development with git and GitHub) and a continually expanding test suite for improved reliability, accuracy, and reproducibility. PINT is developed and implemented without referring to, copying, or transcribing the code from other traditional pulsar timing software packages (e.g., TEMPO and TEMPO2) and therefore provides a robust tool for cross-checking timing analyses and simulating pulse arrival times. In this paper, we describe the design, usage, and validation of PINT, and we compare timing results between it and TEMPO and TEMPO2.Comment: Re-submitted to the Astrophysical Journal at December 31st, 202

    Measurement of spin correlation in ttbar production using a matrix element approach

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    correlation, assuming that the spin of the top quark is either correlated with the spin of the anti-top quark as predicted by the standard model or is uncorrelated. For the first time we use a matrix-element-based approach to study ttbar spin correlation. We use {ttbar -> W+bW-bbar ->l+nubl-nub} final states produced in ppbar collisions at a center of mass energy sqrt(s)=1.96 TeV, where l denotes an electron or a muon. The data correspond to an integrated luminosity of 5.4 fb-1 and were collected with the dzero detector at the Fermilab Tevatron collider. The result agrees with the standard model prediction. We exclude the hypothesis that the spins of the ttbar are uncorrelated at the 97.7% C.L.Comment: 7 pages, 3 figures, submitted to Phys. Rev. Let

    Human immunodeficiency virus type I-specific CD8+ T cell subset abnormalities in chronic infection persist through effective antiretroviral therapy

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    Background: Effective highly active antiretroviral therapy (HAART) reduces human immunodeficiency virus (HIV) replication, restores CD4 +T lymphocyte counts and greatly reduces the incidence of opportunistic infections. While this demonstrates improved generalized immune function, rapid rebound to pre-treatment viral replication levels following treatment interruption indicates little improvement in immune control of HIV replication. The extent to which HAART can normalize HIV-specific CD8 +T cell function over time in individuals with chronic infection remains an important unresolved issue. In this study, we evaluated the magnitude, general specificity and character of HIV specific CD8 +T cell responses at four time points across 2-9 years in 2 groups of chronically infected individuals separated on the basis of either effective antiretroviral suppression or ongoing replication of HIV.Methods: Peripheral blood mononuclear cells (PBMC) were stimulated with overlapping 15mer peptides spanning HIV Gag, Pol, Env and Nef proteins. Cells producing interferon-γ (IFN-γ) or interleukin-2 (IL-2) were enumerated by ELISPOT and phenotyped by flow cytometry.Results and Conclusions: The magnitude of the HIV-specific CD8 +T cell response ranged from < .01 to approximately 1.0% of PBMC and was significantly greater in the group with detectable viral replication. Stronger responses reflected higher numbers of CD8 +CD45RA -effector memory cells producing IFN-γ, but not IL-2. Magnitude, general specificity and character of the HIV-specific CD8 +T cell response changed little over the study period. While antiretroviral suppression of HIV in chronic infection reduces HIV-specific CD8 +T cell response magnitude in the short term, it had no significant effect on response character over periods up to 9 years

    Broad Epigenetic Signature of Maternal Care in the Brain of Adult Rats

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    BACKGROUND: Maternal care is associated with long-term effects on behavior and epigenetic programming of the NR3C1 (GLUCOCORTICOID RECEPTOR) gene in the hippocampus of both rats and humans. In the rat, these effects are reversed by cross-fostering, demonstrating that they are defined by epigenetic rather than genetic processes. However, epigenetic changes at a single gene promoter are unlikely to account for the range of outcomes and the persistent change in expression of hundreds of additional genes in adult rats in response to differences in maternal care. METHODOLOGY/PRINCIPAL FINDINGS: We examine here using high-density oligonucleotide array the state of DNA methylation, histone acetylation and gene expression in a 7 million base pair region of chromosome 18 containing the NR3C1 gene in the hippocampus of adult rats. Natural variations in maternal care are associated with coordinate epigenetic changes spanning over a hundred kilobase pairs. The adult offspring of high compared to low maternal care mothers show epigenetic changes in promoters, exons, and gene ends associated with higher transcriptional activity across many genes within the locus examined. Other genes in this region remain unchanged, indicating a clustered yet specific and patterned response. Interestingly, the chromosomal region containing the protocadherin-α, -β, and -γ (Pcdh) gene families implicated in synaptogenesis show the highest differential response to maternal care. CONCLUSIONS/SIGNIFICANCE: The results suggest for the first time that the epigenetic response to maternal care is coordinated in clusters across broad genomic areas. The data indicate that the epigenetic response to maternal care involves not only single candidate gene promoters but includes transcriptional and intragenic sequences, as well as those residing distantly from transcription start sites. These epigenetic and transcriptional profiles constitute the first tiling microarray data set exploring the relationship between epigenetic modifications and RNA expression in both protein coding and non-coding regions across a chromosomal locus in the mammalian brain

    Combining motion analysis and microfluidics--a novel approach for detecting whole-animal responses to test substances.

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    Small, early life stages, such as zebrafish embryos are increasingly used to assess the biological effects of chemical compounds in vivo. However, behavioural screens of such organisms are challenging in terms of both data collection (culture techniques, drug delivery and imaging) and data evaluation (very large data sets), restricting the use of high throughput systems compared to in vitro assays. Here, we combine the use of a microfluidic flow-through culture system, or BioWell plate, with a novel motion analysis technique, (sparse optic flow - SOF) followed by spectral analysis (discrete Fourier transformation - DFT), as a first step towards automating data extraction and analysis for such screenings. Replicate zebrafish embryos housed in a BioWell plate within a custom-built imaging system were subject to a chemical exposure (1.5% ethanol). Embryo movement was videoed before (30 min), during (60 min) and after (60 min) exposure and SOF was then used to extract data on movement (angles of rotation and angular changes to the centre of mass of embryos). DFT was subsequently used to quantify the movement patterns exhibited during these periods and Multidimensional Scaling and ANOSIM were used to test for differences. Motion analysis revealed that zebrafish had significantly altered movements during both the second half of the alcohol exposure period and also the second half of the recovery period compared to their pre-treatment movements. Manual quantification of tail flicking revealed the same differences between exposure-periods as detected using the automated approach. However, the automated approach also incorporates other movements visible in the organism such as blood flow and heart beat, and has greater power to discern environmentally-driven changes in the behaviour and physiology of organisms. We suggest that combining these technologies could provide a highly efficient, high throughput assay, for assessing whole embryo responses to various drugs and chemicals

    Tunneling Spectra of Individual Magnetic Endofullerene Molecules

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    The manipulation of single magnetic molecules may enable new strategies for high-density information storage and quantum-state control. However, progress in these areas depends on developing techniques for addressing individual molecules and controlling their spin. Here we report success in making electrical contact to individual magnetic N@C60 molecules and measuring spin excitations in their electron tunneling spectra. We verify that the molecules remain magnetic by observing a transition as a function of magnetic field which changes the spin quantum number and also the existence of nonequilibrium tunneling originating from low-energy excited states. From the tunneling spectra, we identify the charge and spin states of the molecule. The measured spectra can be reproduced theoretically by accounting for the exchange interaction between the nitrogen spin and electron(s) on the C60 cage.Comment: 7 pages, 4 figures. Typeset in LaTeX, updated text of previous versio

    The Web Epoch of Reionization Lyman-α\alpha Survey (WERLS) I. MOSFIRE Spectroscopy of z78\mathbf{z \sim 7-8} Lyman-α\alpha Emitters

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    We present the first results from the Web Epoch of Reionization Lyman-α\alpha Survey (WERLS), a spectroscopic survey of Lyman-α\alpha emission using Keck I/MOSFIRE and LRIS. WERLS targets bright (J<26J<26) galaxy candidates with photometric redshifts of 5.5z85.5\lesssim z \lesssim 8 selected from pre-JWST imaging embedded in the Epoch of Reionization (EoR) within three JWST deep fields: CEERS, PRIMER, and COSMOS-Web. Here, we report 11 z78z\sim7-8 Lyman-α\alpha emitters (LAEs; 3 secure and 8 tentative candidates) detected in the first five nights of WERLS MOSFIRE data. We estimate our observed LAE yield is 13\sim13%, broadly consistent with expectations assuming some loss from redshift uncertainty, contamination from sky OH lines, and that the Universe is approximately half-ionized at this epoch, whereby observable Lyman-α\alpha emission is unlikely for galaxies embedded in a neutral intergalactic medium. Our targets are selected to be UV-bright, and span a range of absolute UV magnitudes with 23.1<MUV<19.8-23.1 < M_{\text{UV}} < -19.8. With two LAEs detected at z=7.68z=7.68, we also consider the possibility of an ionized bubble at this redshift. Future synergistic Keck+JWST efforts will provide a powerful tool for pinpointing beacons of reionization and mapping the large scale distribution of mass relative to the ionization state of the Universe.Comment: 27 pages, 8 figures; ApJ submitte
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