Gaia Early Data Release 3: The celestial reference frame (Gaia-CRF3)

Context. Gaia-CRF3 is the celestial reference frame for positions and proper motions in the third release of data from the Gaia mission, Gaia DR3 (and for the early third release, Gaia EDR3, which contains identical astrometric results). The reference frame is defined by the positions and proper motions at epoch 2016.0 for a specific set of extragalactic sources in the (E)DR3 catalogue. Aims. We describe the construction of Gaia-CRF3 and its properties in terms of the distributions in magnitude, colour, and astrometric quality. Methods. Compact extragalactic sources in Gaia DR3 were identified by positional cross-matching with 17 external catalogues of quasi-stellar objects (QSO) and active galactic nuclei (AGN), followed by astrometric filtering designed to remove stellar contaminants. Selecting a clean sample was favoured over including a higher number of extragalactic sources. For the final sample, the random and systematic errors in the proper motions are analysed, as well as the radio-optical offsets in position for sources in the third realisation of the International Celestial Reference Frame (ICRF3). Results. Gaia-CRF3 comprises about 1.6 million QSO-like sources, of which 1.2 million have five-parameter astrometric solutions in Gaia DR3 and 0.4 million have six-parameter solutions. The sources span the magnitude range G = 13-21 with a peak density at 20.6 mag, at which the typical positional uncertainty is about 1 mas. The proper motions show systematic errors on the level of 12 μas yr-1 on angular scales greater than 15 deg. For the 3142 optical counterparts of ICRF3 sources in the S/X frequency bands, the median offset from the radio positions is about 0.5 mas, but it exceeds 4 mas in either coordinate for 127 sources. We outline the future of Gaia-CRF in the next Gaia data releases. Appendices give further details on the external catalogues used, how to extract information about the Gaia-CRF3 sources, potential (Galactic) confusion sources, and the estimation of the spin and orientation of an astrometric solution

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Evolution des rendements selon deux modes de récolte et approche économique "canne à sucre" : réunion, 12 juin - 12 décembre 1985

Le but de l'étude est de vérifier si une différence de rendement existe entre les champs coupés mécaniquement et les champs coupés manuellement. La base de données est les résultats culturaux des sucreries de bourbon. L'étude met en évidence des tendances. Les résultats chiffrés ne sont pas représentatifs de la culture de la canne à sucre à la Réunion, mais reflétent la tendance des sucreries de bourbo

Early small bowel volvulus after gastric bypass: Think about barbed sutures!

International audienceNo abstract availabl

Programme hospitalier de bon usage des antibiotiques : le point de vue des prescripteurs, une enquête nationale

International audienceIntroductionLa lutte contre le développement des résistances bactériennes passe par un usage raisonné des antibiotiques. Pour ce faire, les hôpitaux ont déployé des programmes de bon usage des antibiotiques (PBUA) mais leur succès dépend de l’implication des prescripteurs et du respect des mesures.Matériels et méthodesEnquête réalisée dans 27 hôpitaux, tirés au sort parmi ceux de plus de 300 lits MCO, par auto-questionnaire un jour donné auprès de tous les prescripteurs présents, incluant les internes et les sages-femmes.RésultatsSur 1963 questionnaires distribués, 920 ont été complétés (47 %). Les répondants étaient principalement des médecins seniors (71,7 %), de spécialité médicale (62,4 %) et travaillaient dans des centre hospitalier non universitaires (75,0 %). La présence d’un référent en antibiothérapie était considérée comme un élément central du PBUA (96,2 % d’accord). L’avis du référent était jugé utile pour gérer des problèmes thérapeutiques — choisir le bon antibiotique pour améliorer la situation clinique du patient (84,7 %) ou adapter le traitement à des situations particulières (89,6 %) — mais moins utile pour établir un diagnostic (31,4 %). Les répondants indiquaient que le conseil était majoritairement dispensé par téléphone (72,4 %), à leur demande (96,0 %). Les conseils du référent étaient fréquemment cités (80,2 %) parmi les facteurs influençant les décisions de prescription d’antibiotiques. D’autres facteurs impactaient leurs pratiques comme l’influence des collègues et des supérieurs, notamment pour les internes. Les prescripteurs s’appuyaient davantage sur les recommandations propres à leur spécialité (76,7 %) que sur les recommandations locales (61,5 %). Les prescripteurs citaient peu l’existence d’avis non sollicités ou des contrôles post-prescription. Ils portaient un jugement plutôt négatif sur les mesures visant à restreindre la prescription des antibiotiques, comme la validation par le référent (28,8 %). Ils étaient davantage favorables à des mesures qui augmentent leurs capacités, comme des sessions de formation pour les seniors (74,0 %) ou les internes (73,0 %). La lutte contre les résistances bactériennes était identifiée comme l’un des enjeux du PBUA (77,8 %) mais seuls 51,7 % considéraient l’impact écologique au moment de prescrire.ConclusionLes prescripteurs sont positifs à l’égard des PBUA car ils correspondent à leurs préférences : conseil initié à la demande des cliniciens et peu de mesures contraignantes, dont ils reconnaissent peu l’utilité

Runx2 and MYC collaborate in lymphoma development by suppressing apoptotic and growth arrest pathways in vivo

Members of the Runx and MYC families have been implicated as collaborating oncogenes. The mechanism of this potent collaboration is elucidated in this study of Runx2/MYC mice. As shown previously, ectopic expression of Runx2 in the thymus leads to a preneoplastic state defined by an accumulation of cells with an immature phenotype and a low proliferative rate. We now show that c-MYC overexpression is sufficient to rescue proliferation and to release the differentiation block imposed by Runx2. Analysis of Runx2-expressing lymphomas reveals a consistently low rate of apoptosis, in contrast to lymphomas of MYC mice which are often highly apoptotic. The low apoptosis phenotype is dominant in Runx2/MYC tumors, indicating that Runx2 confers a potent survival advantage to MYC-expressing tumor cells. The role of the p53 pathway in Runx2/MYC tumors was explored on a p53 heterozygote background. Surprisingly, functional p53 was retained in vivo, even after transplantation, whereas explanted tumor cells displayed rapid allele loss in vitro. Our results show that Runx2 and MYC overcome distinct “fail-safe” responses and that their selection as collaborating genes is due to their ability to neutralize each other's negative growth effect. Furthermore, the Runx2/MYC combination overcomes the requirement for genetic inactivation of the p53 pathway in vivo

Runx2: A novel oncogenic effector revealed by in vivo complementation and retroviral tagging

The Runx2 (Cbfa1, Pebp2αA, Aml3) gene was previously identified as a frequent target for transcriptional activation by proviral insertion in T-cell lymphomas of CD2-MYC transgenic mice. We have recently shown that over-expression of the full-length, most highly expressed Runx2 isoform in the thymus perturbs T-cell development, leads to development of spontaneous lymphomas at low frequency and is strongly synergistic with Myc. To gain further insight into the relationship of Runx2 to other lymphomagenic pathways, we tested the effect of combining the CD2-Runx2 transgene either with a Pim1 transgene (Eμ-Pim1) or with the p53 null genotype, as each of these displays independent synergy with Myc. In both cases we observed synergistic tumour development. However, Runx2 appeared to have a dominant effect on the tumour phenotype in each case, with most tumours conforming to the CD3+, CD8+, CD4+/− phenotype seen in CD2-Runx2 mice. Neonatal infection of CD2-Runx2 mice with Moloney murine leukaemia virus (Moloney MLV) also led to a dramatic acceleration of tumour onset. Analysis of known Moloney MLV target genes in these lymphomas showed a high frequency of rearrangement at c-Myc or N-Myc (82%), and a significant number at Pim1 or Pim2 (23%), and at Pal1/Gfi1 (18%). These results indicate that Runx2 makes a distinct contribution to T-cell lymphoma development which does not coincide with any of the oncogene complementation groups previously identified by retroviral tagging

L'échantillonnage

* INRA - Unité de Biométrie, Centre de Toulouse (FRA) Diffusion du document : INRA - Unité de Biométrie, Centre de Toulouse (FRA)National audienc

Influence de la microstructure et des caracteristiques mecaniques des alliages 600 et 690 sur la fissuration en milieu secondaire

SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : 26165 A, issue : a.1996 n.169 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc