The XMM-Newton Optical Monitor Survey of the Taurus Molecular Cloud

The Optical Monitor (OM) on-board XMM-Newton obtained optical/ultraviolet data for the XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST), simultaneously with the X-ray detectors. With the XEST OM data, we aim to study the optical and ultraviolet properties of TMC members, and to do correlative studies between the X-ray and OM light curves. In particular, we aim to determine whether accretion plays a significant role in the optical/ultraviolet and X-ray emissions. The Neupert effect in stellar flares is also investigated. Coordinates, average count rates and magnitudes were extracted from OM images, together with light curves with low time resolution (a few kiloseconds). For a few sources, OM FAST mode data were also available, and we extracted OM light curves with high time resolution. The OM data were correlated with Two Micron All Sky Survey (2MASS) data and with the XEST catalogue in the X-rays. The XEST OM catalogue contains 2,148 entries of which 1,893 have 2MASS counterparts. However, only 98 entries have X-ray counterparts, of which 51 of them are known TMC members and 12 additional are TMC candidates. The OM data indicate that accreting stars are statistically brighter in the U band than non-accreting stars after correction for extinction, and have U-band excesses, most likely due to accretion. The OM emission of accreting stars is variable, probably due to accretion spots, but it does not correlate with the X-ray light curve, suggesting that accretion does not contribute significantly to the X-ray emission of most accreting stars. In some cases, flares were detected in both X-ray and OM light curves and followed a Neupert effect pattern, in which the optical/ultraviolet emission precedes the X-ray emission of a flare, whereas the X-ray flux is proportional to the integral of the optical flux.Comment: Accepted by A&A, to appear in a special section/issue dedicated to the XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST). Version with higher resolution figures available at this http://www.issibern.ch/teams/Taurus/papers.htm

Conséquences rénales de l'activation de la réponse UPR (Unfolded protein response) par des stress toxique et ischémique

Le rein natif et le greffon rénal peuvent être soumis à de multiples agressions conduisant à la détérioration progressive du parenchyme. Ces agressions peuvent être spécifiques (stress toxique, immunologique) et/ou non spécifiques (stress ischémique) et vont engendrer des réponses pouvant entraîner à la fois une diminution de la consommation d énergie, une augmentation des apports afin de maintenir l homéostasie tissulaire et la survie mais aussi une réaction inflammatoire et l apoptose pouvant conduire à la fibrose. Parmi celles-ci, on peut nommer les voies HIF1a, mTOR, le stress du réticulum endoplasmique (RE), l autophagie, l activation de l immunité innée et acquise. La réponse adaptative qui suit le stress du RE, la réponse UPR (Unfolded protein response), est une voie adaptative dont les implications sont actuellement encore peu connues dans le domaine de la pathologie rénale. Celle-ci se compose de trois effecteurs principaux : Perk, Ire1 et ATF6. A l aide de deux modèles de stress toxique (ciclosporine) et ischémique (carence en glucose) sur deux modèles cellulaires distincts (cellulaires endothéliales artérielles et cellules tubulaires rénales), et dans des modèles in vivo, nous avons montré que le stress du RE était impliqué à la fois dans l apparition de modifications phénotypiques endothéliales évocatrices de transition endothélio-mésenchymateuse induites par la ciclosporine et à la fois dans l induction de réponses inflammatoire (régulation de NF- B par Ire1) et angiogénique (régulation distincte de VEGF, bFGF et angiogénine par Perk et Ire1) induites par la carence en glucose. La réponse UPR semble modulée de façon subtile au cours de ces stress car les trois effecteurs n engendrent pas des réponses identiques. Ces travaux apportent ainsi une meilleure compréhension des mécanismes d adaptation au cours de stress variés, montrent que le stress du RE est impliqué dans ces réponses adaptatives et que la réponse peut être différente selon les effecteurs de la réponse UPR. Cette meilleure compréhension pourra permettre de valider des biomarqueurs précoces et des modulateurs de la réponse UPR afin de prévenir la dégradation du parenchyme rénal.Native and grafted kidneys are stressed by multiple specific or non-specific insults leading to progressive structural deterioration. Responses to these insults are adaptive and preserve cell survival but may also promote inflammation, fibrosis and apoptosis. The most important of these adaptive pathways are HIF1a pathway, mTOR pathway, autophagy, unfolded protein response (UPR). The consequences of the UPR in kidney injuries are not well known. The objective of this study is to delineate the mechanisms and consequences of the activation of the UPR in response to toxic (cyclosporine) and ischemic (glucose starvation) stresses in two distinct cellular models (arterial endothelial cells and renal tubular cells). Here, we showed that UPR was engaged in cyclosporine-induced endothelial phenotypic changes, glucose starvation-induced inflammatory and angiogenic responses: NF- B regulation by Ire1; distinct VEGF, bFGF and angiogenin regulation by Perk and Ire1. UPR is subtly modulated since its transducers do not induce identical processes. In conclusion these comprehensive works, we demonstrate the UPR is implicated in stress-induced adaptive pathways with different downstream responses according to the effector. Renal tissue degradation could be prevented by discovering and validating early biomarker and UPR modulators.PARIS5-Bibliotheque electronique (751069902) / SudocPARIS-BIUM-Bib. électronique (751069903) / SudocSudocFranceF

An Unified FPT Algorithm for Width of Partition Functions

During the last decades, several polynomial-time algorithms have been designed that decide whether a graph has tree-width (resp., path-width, branch-width, etc.) at most k, where k is a fixed parameter. Amini et al. (Discrete Mathematics'09) use the notions of partitioning-trees and partition functions as a generalized view of classical decompositions of graphs, namely tree decomposition, path decomposition, branch decomposition, etc. In this paper, we propose a set of simple sufficient conditions on a partition function Φ, that ensures the existence of a linear-time explicit algorithm deciding if a set A has Φ-width at most k (k fixed). In particular, the algorithm we propose unifies the existing algorithms for tree-width, path-width, linear-width, branch-width, carving-width and cut-width. It also provides the first Fixed Parameter Tractable linear-time algorithm to decide if the q-branched tree-width, defined by Fomin et al. (Algorithmica'09), of a graph is at most k (k and q are fixed). Moreover, the algorithm is able to decide if the special tree-width, defined by Courcelle (FSTTCS'10), is at most k, in linear-time where k is a Fixed Parameter. Our decision algorithm can be turned into a constructive one by following the ideas of Bodlaender and Kloks (J. of Alg. 1996).Au cours de ces dernières années, plusieurs algorithmes polynomiaux ont été conçus pour décider si un graphe a largeur arborescente (resp., largeur en chemin, branch-width, etc) au plus k, où k est un paramètre fixe. Amini et al. (Discrete Mathematics'09) ont utilisé les notions d'arbres de partition et de fonctions de partition comme une vision généralisée des décompositions des graphes classiques, à savoir la décomposition arborescente, la décomposition en chemin, la décomposition en branche, etc. Dans cet article, nous proposons un ensemble de conditions sur une fonction de partition Φ, qui assure l'existence d'un algorithme explicite en temps linéaire pour décider si un ensemble A a Φ-largeur au plus k (oú k est fixé). En particulier, l'algorithme que nous proposons unifie les algorithmes existants pour la largeur arborescente, largeur en chemin, la largeur linéaire, la largeur de branche, cut-width et carving-width. Il est également le premier algorithme FPT pour décider si la largeur arborescente q-ramifié, définie par Fomin et al. (Algorithmica'09), d'un graphe est au plus k (k et q sont fixées). De plus, l'algorithme est capable de décider si la largeur arborescente spéciale, définie par Courcelle (FSTTCS'10), est plus k, où k est un paramètre fixé. Notre algorithme de décision peut être transformé en un algorithme constructif en suivant les idées de Bodlaender et Kloks (J. of Alg., 1996)

Luminescence dating applied to medieval architecture

Avranches’ keep remains constitute a witness of Anglo-Norman knowledge on castle building. Their similarity with other buildings such as Ivry-la-Bataille castle or London Tower required determining the place of Avranches keep in this group: pioneer or imitation? Therefore, samples of brick for luminescence dating were taken from the remaining little tower. Results indicate a chronology later than assumed: second part of the 12th century and first part of 13th century. These dates tend to prove that north-east tower remains would correspond to a reconstruction phase and not to the original construction.Le donjon d’Avranches représente un des rares témoins de l’architecture castrale anglo-normande. Son plan présente d’importantes resemblance avec d’autres edifices de du même contexte chrono-culturel, comme le donjon d’Ivry-la-Bataille ou la Tour de Londres. Ces ressemblances posent la question de la place du donjon d’Avranches dans cet ensemble : s’agit-il d’un édifice précurseur ou d’une imitation ? C’est pourquoi plusieurs prélèvements de brique ont été prélevés dans les vestiges de ce bâtiment, afin de procéder à la datation de la sa construction. Les résultats semblent suggérer une construction plus tardive qu’on ne l’envisageait, entre la deuxième moitié du xiie siècle et la première moitié du xiiie siècle. Ces dates pourraient suggérer une reconstruction partielle du donjon, sans correspondre à la phase de construction originale du château

Quasi-periodic X-ray Flares from the Protostar YLW15

With ASCA, we have detected three X-ray flares from the Class I protostar YLW15. The flares occurred every ~20 hours and showed an exponential decay with time constant 30-60 ks. The X-ray spectra are explained by a thin thermal plasma emission. The plasma temperature shows a fast-rise and slow-decay for each flare with kT_{peak}~4-6 keV. The emission measure of the plasma shows this time profile only for the first flare, and remains almost constant during the second and third flares at the level of the tail of the first flare. The peak flare luminosities L_{X,peak} were ~5-20 * 10^{31} erg s^{-1}, which are among the brightest X-ray luminosities observed to date for Class I protostars. The total energy released in each flare was 3-6*10^{36} ergs. The first flare is well reproduced by the quasi-static cooling model, which is based on solar flares, and it suggests that the plasma cools mainly radiatively, confined by a semi-circular magnetic loop of length ~14 Ro with diameter-to-length ratio \~0.07. The two subsequent flares were consistent with the reheating of the same magnetic structure as of the first flare. The large-scale magnetic structure and the periodicity of the flares imply that the reheating events of the same magnetic loop originate in an interaction between the star and the disk due to the differential rotation.Comment: Accepted by ApJ, 9 pages incl. 4 ps figure

Rotation and X-ray emission from protostars

The ASCA satellite has recently detected variable hard X-ray emission from two Class I protostars in the rho Oph cloud, YLW15 (IRS43) and WL6, with a characteristic time scale ~20h. In YLW15, the X-ray emission is in the form of quasi-periodic energetic flares, which we explain in terms of strong magnetic shearing and reconnection between the central star and the accretion disk. In WL6, X-ray flaring is rotationally modulated, and appears to be more like the solar-type magnetic activity ubiquitous on T Tauri stars. We find that YLW15 is a fast rotator (near break-up), while WL6 rotates with a significantly longer period. We derive a mass M_\star ~ 2 M_\odot and \simlt 0.4 M_\odot for the central stars of YLW15 and WL6 respectively. On the long term, the interactions between the star and the disk results in magnetic braking and angular momentum loss of the star. On time scales t_{br} ~ a few 10^5 yrs, i.e., of the same order as the estimated duration of the Class~I protostar stage. Close to the birthline there must be a mass-rotation relation, t_{br} \simpropto M_\star, such that stars with M_\star \simgt 1-2 M_\odot are fast rotators, while their lower-mass counterparts have had the time to spin down. The rapid rotation and strong star-disk magnetic interactions of YLW15 also naturally explain the observation of X-ray ``superflares''. In the case of YLW15, and perhaps also of other protostars, a hot coronal wind (T~10^6 K) may be responsible for the VLA thermal radio emission. This paper thus proposes the first clues to the rotation status and evolution of protostars.Comment: 13 pages with 6 figures. To be published in ApJ (April 10, 2000 Part 1 issue

Pattern of DAP12 Expression in Leukocytes from Both Healthy and Systemic Lupus Erythematosus Patients

DAP12 is an ITAM-bearing transmembrane adaptor originally identified on the surface of Natural Killer cells. A broad expression among other immune cells was later found in myeloid and lymphoid cells. However, data on DAP12 expression pattern rely only on immunoblot and microarray analysis. Here, we describe the generation and the characterization of an anti-DAP12 monoclonal antibody. Using this novel reagent, we show that DAP12 expression is restricted to innate immune cells in basal condition. Since a decreased expression of DAP12 has been suggested in NK cells of systemic lupus erythematosus patients, we have further investigated the NK cell receptor repertoire and leukocyte expression of DAP12 in these patients and no major changes were detectable when compared to controls

Congenital and Disseminated Pyogenic Granuloma-like Vascular Lesions

International audienceWe report an exceptional case of multiple cutaneous and visceral neonatal pyogenic granuloma (PG) initially suggestive of a diffuse neonatal haemangiomatosis. CASE REPORT A full-term female newborn, with no significant past medical history, was referred to our department for treatment of an acute respiratory distress syndrome of neurological origin at day 8 of life. At birth, she presented with 3 small angiomatous papules and 4 subcutaneous nodules suggestive of neonatal hae-mangiomatosis (NH) (Fig. 1). A brain MRI revealed a highly vascularised brain stem tumour suggestive of glioma (Fig. 2), associated with 2 abnormal hepatic lesions consistent with infantile haemangiomas (IH) on ultrasound and CT scan. Methylprednisolone was started for the suspected glioma-associated oedema, and vincristine and propranolol were introduced for NH. After initial improvement, an acute intracranial hypertension related to cystic evolution of the disease necessitated surgical resection at the age of 2 months. Pathological examinations of the brain, cutaneous and subcutaneous lesions were similar, showing a vascular lobular proliferation of capillaries highly suggestive of PG. The misdiagnosis of glioma was eliminated. The GLUT-1 antigen marker was negative, ruling out the diagnosis of NH-like infantile haemangioma (Fig. 3). Lymphatic marker (D2-40) was also negative and eliminated a multifocal lymphangioendotheliomato-sis with thrombocytopaenia (MLT). Cutaneous and hepatic lesions gradually regressed. She is currently in complete remission after completing a treatment over 18 months with propranolol but a spontaneous improvement can not be excluded. DISCUSSIO

Matrix Isolation Infrared Spectroscopic and Theoretical Study of the Interaction of Water with Dimethyl Methylphosphonate

Matrix isolation infrared spectroscopy has been combined with theoretical calculations for the characterization of the 1:1 hydrogen-bonded complex between H2O and dimethyl methylphosphonate (DMMP). The symmetric O-H stretching mode was observed to shift 203 cm-1 to lower energy upon hydrogen bond formation, while a 32 cm-1 blue shift was noted for the H-O-H bending mode of the H2O subunit in the complex. These values compare extremely well with the (unscaled) shifts of -203 and +32 cm-1, respectively, that were calculated theoretically at the MP2/6-31+G** level. Additional perturbed modes of the DMMP subunit were observed, shifted relative to the parent band position. The greatest perturbation was to the P=O stretching mode near 1270 cm-1, where a shift of -17 cm-1 was observed (-21 cm-1 calculated theoretically). This suggests that the site of hydrogen bonding in the complex is at the P=O group, in agreement with theoretical calculations. The binding energy ΔE° for the 1:1 complex was calculated to be -7.7 kcal/mol