Sedimentary processes in the Thau Lagoon (France): From seasonal to century time scales

As a part of the MICROBENT programme, an investigation of the sedimentation framework was carried out at the water-sediment interface in the Thau Lagoon (French Mediterranean coast). Two main sites, C4 in the middle of the lagoon and C5 near oyster farms, were visited six times between December 2001 and May 2003. Interface sediments were studied using classical sedimentology parameters (radiography RX, grain size distribution) and analysis of selected radionuclides (234Th, 7Be, 210Pb, 226Ra). On a century time scale, excess 210Pb (210Pbxs) presents classical profiles with an upper mixed layer, followed by an exponential decrease of activities to undetectable levels below 20 – 30 cm. At the central site, C4, cores seem to register episodic changes in mean grain size, presenting recurrently peaks. The upper 10 cm of 210Pbxs profiles at site C5 exhibit a mixed layer associated with coarser sediments: this could be related to biological activity. Sedimentation rates derived from 210Pbxs varied from 0.15 cm y−1 at the edge of the basin, to 0.25 cm y−1 at the central site. On a seasonal time scale, 234Th and 7Be both show significant variations in activities and in penetration within the sediment. Bioturbation rates derived from both radionuclides agree well and range between 1–10 cm2 y−1 at site C4 and 1–31 cm2 y−1 at site C5. 234Th and 7Be fluxes at the water-sediment interface show too seasonal variations, more pronounced for site C5. This latter site presents especially a higher variability that is well marked with season, probably in relation with its position near oyster farms

Transdisciplinarity: a new mode of governing science?

What exactly does it mean to integrate extra-academic types of knowledge, interests and values into the procedures of scientific knowledge production? In this paper, we shall approach these questions from a ‘lab study perspective', investigating the discourses and practices that constitute doing transdisciplinarity. Based upon an ongoing empirical research project, we call for a novel perspective: the task of producing ‘socially robust knowledge', often couched in terms of extended responsibility of science vis-á-vis society, can also be regarded as a specific instance of neo-liberal rationality in research practice and science policy, at large. As scientific claims to accountability and truth have come under critique throughout the last decades, they now have to be reworked on the micro-level of transdisciplinary projects. Transdisciplinarity is thus revealed as a new mode of governing science in societ

Contamination of spectroscopic observations by satellite constellations

The number of satellites on low orbit has dramatically increased over the past years, raising concerns among the astronomical community about their impact on observations. Spectroscopic observations represent a large fraction of professional data, and spectrographs lack spatial information that can reveal the presence of a satellite. We simulated how often satellites contaminate spectrograph observations by using realistic constellations with over 400,000 objects. We also measured how a spectrum is affected by using real data from different scientific targets and a scaled solar analogue as the satellite, and using standard tools to measure astrophysical parameters and compare them with the clean spectrum. The fraction of affected spectra varies dramatically with the elevation of the sun, with a maximum of 10% at twilight and a nightly average of about 2%. Because of the fast motion of the satellites and the limiting magnitude of the spectrographs, high-resolution instruments are essentially blind to most satellites. For lower resolution spectrographs, the effect on the measured astrophysical parameters depends strongly on the signal-to-noise of the exposure, longer exposures on brighter targets being the least affected at <=1%. Satellites that are brighter and/or higher than the constellation satellites, while less numerous, can also contaminate spectra. While the fraction of affected spectra is likely to remain low, some of these contaminated spectra will be difficult to identify, as it is already the case with existing satellites and asteroids. The best mitigation is to ensure that their brightness is fainter than V=7, that their absolute magnitude V1000km is also fainter than 7, and, whenever possible, to shoot multiple exposures.Comment: accepted for publication in A&

Les déterminants individuels des absences au travail : une comparaison européenne.

À partir des données de l’European Community Household Panel (ECHP), on s’intéresse aux déterminants individuels des absences au travail dans les pays européens. L’étude porte sur l’ensemble des États membres de l’UE-15, à l’exception de la Suède. Les comportements d’absence des salariés, dans chacun de ces pays, sont analysés à l’aide de deux modèles sur données de panel : un modèle Probit à effets aléatoires et un modèle Logit à effets fixes. Ces modèles sont estimés séparément pour les hommes et pour les femmes. Afin de tenir compte de l’éventuelle endogénéité du degré de satisfaction à l’égard de l’emploi occupé, on procède également à l’estimation de modèles Probit bivariés, permettant d’expliquer simultanément l’insatisfaction au travail et l’absence. Comme différents travaux antérieurs, cette comparaison européenne fait apparaître des écarts sensibles de taux d’absence entre les pays. On constate que les taux observés en France, au cours de la période 1994-2001, sont parmi les plus faibles de l’UE, les durées d’absence pour les salariés français étant cependant plus longues, en moyenne, que celles enregistrées dans la plupart des autres pays (du moins si l’on en juge d’après les chiffres relatifs aux années 1998 à 2001). Les résultats des estimations montrent que les facteurs jouant sur la probabilité d’absence sont loin d’être identiques d’un pays à l’autre. L’existence d’une maladie chronique ou d’un handicap, le degré de satisfaction au travail et, chez les femmes, la présence d’un enfant de moins de 3 ans sont, en effet, les seules variables qui ont un impact significatif, et de même signe, dans la quasi-totalité des États de l’UE-15 (d’après les résultats des modèles Probit à effets aléatoires).absences au travail, santé, satisfaction au travail, Union européenne.

Développement durable et gestion internationale : enjeux et perspectives d'avenir.

Développement durable et gestion internationale : enjeux et perspectives d'avenir. Texte d'introduction au numéro thématiqueCommerce international; Développement durable;

Direct contact of platelets and their released products exert different effects on human dendritic cell maturation

<p>Abstract</p> <p>Background</p> <p>Dendritic cells (DCs) are antigen presenting cells capable of inducing innate and adaptive immune responses. According to the stimulus and their maturation state, DCs induce immunogenic or tolerogenic responses. Platelets (PLTs), which are involved in haemostasis and inflammation, can also interact with DCs. In this study, we examined the effect of PLTs on DC maturation <it>in vitro</it>. Human monocyte-derived DCs were co-cultured for 2 days with homologous PLTs either in the same well or in 0.4 μm-pore size filter-separated compartments.</p> <p>Results</p> <p>Confocal microscopy showed the attachment of PLTs to DC membranes. The DC receptor involved in this interactions was found to be CD162. In addition, we observed that DCs co-cultured with PLTs in filter-separated compartments acquired a mature phenotype (high CD80, CD86, and intermediate CD83 expression; IL-12(p70) production; efficient stimulation of autologous CD4+ T cell proliferation), while DCs co-cultured with PLTs in the same compartment did not undergo phenotypic maturation, did not secrete IL-12(p70) or IL-1β, but instead induced moderate Th2-polarized T cell proliferation.</p> <p>Conclusion</p> <p>These data indicate that (i) PLTs secrete a soluble DC-activating factor that was demonstrated not to be soluble CD40-Ligand (CD154; as could have been expected from <it>in vivo </it>and previous <it>in vitro </it>work) but to be nucleotide, and (ii) that cell-to-cell contact did not induce DC maturation, possibly because nucleotide release by PLTs was prevented by direct contact with DCs. This work demonstrates that PLTs are active elements of the immune system that might play a role in balancing the ability of DCs to polarize T cell responses, therefore making them critical factors in transfusion processes.</p

Robust Brain-computer interface for virtual Keyboard (RoBIK): project results

Special issue : ANR TECSAN : Technologies for Health and AutonomyNational audienceBrain-ComputerInterface (BCI)is a technology that translatesthe brain electrical activity into a command for a device such as a robotic arm, a wheelchair or a spelling device. BCIs have long been described as an assistive technology forseverely disabled patients because they completely bypass the need for muscular activity. The clinical reality is however dramatically different and most patients who use BCIs today are doing so as part of constraining clinical trials. To achieve the technological transfer from bench to bedside, BCI must gain ease of use and robustness of bothmeasure (electroencephalography [EEG]) and interface (signal processing and applications).TheRobustBrain-computerInterface for virtual Keyboard (RoBIK) project aimed atthe development of aBCIsystemfor communication that could be used on a daily basis by patientswithoutthe help of a trained teamofresearchers.To guide further developments cliniciansfirst assessed patients' needs.The prototype subsequently developed consisted in a 14 felt-pad electrodes EEG headsetsampling at 256Hz by an electronic component capable of transmitting signals wirelessly. The application was a virtual keyboard generating a novelstimulation paradigm to elicit P300 Evoked Related Potentials(ERPs) for communication. Raw EEG signals were treated with OpenViBE open-source software including novelsignal processing and stimulation techniques

Choix d’activité des mères et garde des jeunes enfants : une comparaison entre les pays de l’Europe des Quinze à partir des données de l’ECHP.

À partir des données de la vague 7 (2000) de l’European Community Household Panel (ECHP), cet article s’intéresse aux choix d’activité des mères en Europe et à leur décision, lorsqu’elles ont de jeunes enfants à charge, de recourir ou non aux services de garde. L’étude porte sur l’ensemble des États membres de l’UE-15. Après un bref survol des politiques de conciliation entre vie familiale et vie professionnelle mises en oeuvre dans les pays européens et l’exposé de différents résultats descriptifs, les comportements des mères, dans chacun de ces pays, sont analysés à l’aide de deux modèles Logit polytomiques (non ordonnés). Le premier modèle se focalise sur la décision d’offre de travail (une distinction étant introduite entre activité à temps partiel et activité à temps complet). Dans le second modèle, on oppose les trois situations suivantes : (1) non-emploi ; (2) emploi et garde intra-ménage ou non rémunérée ; (3) emploi et garde rémunérée. Les résultats des estimations montrent que l’ampleur des effets des principaux facteurs pris en compte (taux de salaire, niveau de rémunération du conjoint, nombre d’enfants à charge et âge du plus jeune enfant) varie assez fortement selon les pays. S’agissant de l’impact de la présence d’un enfant de moins de 3 ans sur la probabilité d’emploi des mères, les différences observées semblent pouvoir s’expliquer en partie par les caractéristiques des dispositifs de conciliation entre vie familiale et vie professionnelle.activité féminine, travail à temps partiel, garde des jeunes enfants, Union européenne.

Navigating the heavy seas of online publishing:Reflections on ten years editorship

Articulo – Journal of Urban Research celebrates its 10th anniversary! To celebrate this milestone, the current editors discuss the numerous changes and challenges related to publishing a peer-reviewed online journal. Since 2005, Articulo has progressively become more international, more professional, and more specialized than its initiators ever dreamed it could be. In ten years, the rather confidential publication has progressively become a journal read by 9,000 people every month. Our editors, who used to work side by side, now live 6,000 km apart. In the midst of often tumultuous change, what hasn't changed is our commitment to the highest quality of publication and our conviction that knowledge – especially if funded by public money – should be universally and freely accessible. Rigorous peer-review and open access are the two principles on which the journal will navigate the often rough seas of online publishing in the future