Surface Activity and Oscillation Amplitudes of Red Giants in Eclipsing Binaries

Among 19 red-giant stars belonging to eclipsing binary systems that have been identified in Kepler data, 15 display solar-like oscillations. We study whether the absence of mode detection in the remaining 4 is an observational bias or possibly evidence of mode damping that originates from tidal interactions. A careful analysis of the corresponding Kepler light curves shows that modes with amplitudes that are usually observed in red giants would have been detected if they were present. We observe that mode depletion is strongly associated with short-period systems, in which stellar radii account for 16-24 % of the semi-major axis, and where red-giant surface activity is detected. We suggest that when the rotational and orbital periods synchronize in close binaries, the red-giant component is spun up, so that a dynamo mechanism starts and generates a magnetic field, leading to observable stellar activity. Pressure modes would then be damped as acoustic waves dissipate in these fields.Comment: 11 pages, 10 figures, Accepted in Ap

Intracellular Calcium And The Regulation Of Growth Hormone Release By Growth Hormone-releasing Factor And Somatostatin In Rat Somatotrophs

The release of growth hormone (GH) from the somatotrophs of the anterior pituitary is under the control of two hypothalamic peptides, GH-releasing factor (GRF) and somatostatin (SRIF), which stimulates and inhibits release respectively. The aim of this study was to explore the role of intracellular Ca{dollar}\sp{lcub}2+{rcub}{dollar} ( (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar}) in the regulation of GH release by GRF and SRIF in acutely dispersed purified rat somatotrophs.;The role of extracellular Ca{dollar}\sp{lcub}2+{rcub}{dollar} was studied by assessing the effect of Ca{dollar}\sp{lcub}2+{rcub}{dollar}-free medium and Ca{dollar}\sp{lcub}2+{rcub}{dollar} antagonists on GRF-induced GH release. The fluorescent dye indo-1 was used to measure (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar}. Ca{dollar}\sp{lcub}2+{rcub}{dollar} influx was evaluated by measuring {dollar}\sp{lcub}45{rcub}{dollar}Ca uptake.;GRF-stimulated GH release was inhibited in Ca{dollar}\sp{lcub}2+{rcub}{dollar}-free medium. The Ca{dollar}\sp{lcub}2+{rcub}{dollar} anatagonists nifedipine and diltiazem, inhibited basal, K{dollar}\sp{lcub}+{rcub}{dollar}- and GRF-induced GH release. GRF stimulated a triphasic increase in {dollar}\sp{lcub}45{rcub}{dollar}Ca uptake. GRF also stimulated a biphasic increase in (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar}, which was entirely dependent on Ca{dollar}\sp{lcub}2+{rcub}{dollar} influx. SRIF decreased {dollar}\sp{lcub}45{rcub}{dollar}Ca uptake in steady and non-steady states. It also inhibited the steady state GRF-induced increase in {dollar}\sp{lcub}45{rcub}{dollar}Ca uptake. SRIF lowered baseline (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar} and inhibited the increase in (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar} stimulated by GRF. To study the underlying mechanisms involved in the control of (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar} by GRF and SRIF, the effect of K{dollar}\sp{lcub}+{rcub}{dollar} depolarization, cAMP analogues and protein kinase C (PKC) activators on Ca{dollar}\sp{lcub}2+{rcub}{dollar} fluxes and (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar}, were examined. K{dollar}\sp{lcub}+{rcub}{dollar}-dependent depolarization stimulated a nifedipine-sensitive Ca{dollar}\sp{lcub}2+{rcub}{dollar} influx which was not inhibited by SRIF, and which resulted in an increase in (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar}. 8-(4-Chlorophenylthio)-cAMP raised (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar} by stimulating a nifedipine- and SRIF-sensitive Ca{dollar}\sp{lcub}2+{rcub}{dollar} influx. The PKC activators 1,2-dioctanoylglycerol and the phorbol 12-myristate 13-acetate raised (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar} by stimulating a nifedipine- and SRIF-sensitive Ca{dollar}\sp{lcub}2+{rcub}{dollar} influx.;The conclusions of this study are (a) Ca{dollar}\sp{lcub}2+{rcub}{dollar} is essential for GRF-induced GH release; (b) GRF stimulates Ca{dollar}\sp{lcub}2+{rcub}{dollar} influx which results in a biphasic increase in (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar}; (c) SRIF lowers (Ca{dollar}\sp{lcub}2+{rcub}{dollar}) {dollar}\sb{lcub}\rm i{rcub}{dollar} by inhibiting Ca{dollar}\sp{lcub}2+{rcub}{dollar} influx; (d) GRF could stimulate Ca{dollar}\sp{lcub}2+{rcub}{dollar} influx by depolarizing the cell or by increasing cAMP- and PKC-dependent phosphorylation

The red giants in NGC 6633 as seen with CoRoT, HARPS and SOPHIE

The open cluster NGC 6633 was observed with CoRoT in 2011 and simultaneous high-resolution spectroscopy was obtained with the SOPHIE and HARPS spectrographs. One of the four targets was not found to be a cluster member. For all stars we provide estimates of the seismic and spectroscopic parameters.Comment: Proc. of the workshop "Asteroseismology of stellar populations in the Milky Way" (Sesto, 22-26 July 2013), Astrophysics and Space Science Proceedings, (eds. A. Miglio, L. Girardi, P. Eggenberger, J. Montalban

A novel time series analysis approach for prediction of dialysis in critically ill patients using echo-state networks

Background: Echo-state networks (ESN) are part of a group of reservoir computing methods and are basically a form of recurrent artificial neural networks (ANN). These methods can perform classification tasks on time series data. The recurrent ANN of an echo-state network has an 'echo-state' characteristic. This 'echo-state' functions as a fading memory: samples that have been introduced into the network in a further past, are faded away. The echostate approach for the training of recurrent neural networks was first described by Jaeger H. et al. In clinical medicine, until this moment, no original research articles have been published to examine the use of echo-state networks. Methods: This study examines the possibility of using an echo-state network for prediction of dialysis in the ICU. Therefore, diuresis values and creatinine levels of the first three days after ICU admission were collected from 830 patients admitted to the intensive care unit (ICU) between May 31th 2003 and November 17th 2007. The outcome parameter was the performance by the echo-state network in predicting the need for dialysis between day 5 and day 10 of ICU admission. Patients with an ICU length of stay < 10 days or patients that received dialysis in the first five days of ICU admission were excluded. Performance by the echo-state network was then compared by means of the area under the receiver operating characteristic curve (AUC) with results obtained by two other time series analysis methods by means of a support vector machine (SVM) and a naive Bayes algorithm (NB). Results: The AUC's in the three developed echo-state networks were 0.822, 0.818, and 0.817. These results were comparable to the results obtained by the SVM and the NB algorithm. Conclusions: This proof of concept study is the first to evaluate the performance of echo-state networks in an ICU environment. This echo-state network predicted the need for dialysis in ICU patients. The AUC's of the echo-state networks were good and comparable to the performance of other classification algorithms. Moreover, the echostate network was more easily configured than other time series modeling technologies

Propagation de fissures tridimensionnelles dans des matériaux inélastiques avec XFEM dans Cast3m

National audienceSee http://hal.archives-ouvertes.fr/docs/00/59/27/09/ANNEX/r_GI7M6O5P.pd

A metapopulation model to simulate West Nile virus circulation in Western Africa, Southern Europe and the Mediterranean basin

In Europe, virological and epidemiological data collected in wild birds and horses suggest that a recurrent circulation of West Nile virus (WNV) could exist in some areas. Whether this circulation is permanent (due to overwintering mechanisms) or not remains unknown. The current conception of WNV epidemiology suggests that it is not: this conception combines an enzootic WNV circulation in tropical Africa with seasonal introductions of the virus in Europe by migratory birds. The objectives of this work were to (i) model this conception of WNV global circulation; and (ii) evaluate whether the model could reproduce data and patterns observed in Europe and Africa in vectors, horses, and birds. The model was calibrated using published seroprevalence data obtained from African (Senegal) and European (Spain) wild birds, and validated using independent, published data: seroprevalence rates in migratory and resident wild birds, minimal infection rates in vectors, as well as seroprevalence and incidence rates in horses. According to this model, overwintering mechanisms are not needed to reproduce the observed data. However, the existence of such mechanisms cannot be ruled out

Pathways to high performance: a Qualitative Comparative Analysis of sport governing bodies

Nonprofit organizations are facing increasing pressure to become more performance oriented. Most research in this area has focused on the effects of a variety of independent variables on performance with little research focusing on combinations of factors that impact on performance. This article focuses on sport governing bodies from Belgium and measures and assesses their strategic goals and potential determinants of performance. Due to the small N-sample and the causal complexity inherent in this research, a crisp-set Qualitative Comparative Analysis (csQCA) was carried out which highlighted three pathways associated with high performance. High performance could be delivered by sport governing bodies that develop innovative activities for their members and are proactive in elite sport services; or that develop innovative activities and involve paid staff in decision-making processes; or that involve committed volunteers in decision-making processes and delegate activities they are not able to deliver themselves

Magnetic Resonance Imaging findings in a Positron Emission Tomography-Positive thoracic aortic aneurysm

peer reviewe

Combined RFID Tag Antenna for Recipients Containing Liquids

International audienceIn UHF RFID (radio frequency identification), passive tag antennascan be fixed on boxes or recipients where the nature and contentsmight vary. These variations strongly affect the antenna performance.A combined antenna is proposed to ensure an effective read-range for aplastic recipient containing water or not. Two separate antennas arefirst designed for the filled and unfilled cases, respectively, thencombined for a correct working in both configurations