Discovery of transient high-energy gamma-ray emission from the BL Lacertae object 5C 3.178

We report the serendipitous discovery of transient, point-like high energy gamma-ray emission coincident with the position of the suspected BL Lac object 5C 3.178. The source was detected using the Fermi Large Area Telescope (LAT) at a significance level of ~8 sigma during a 200 day period which began on MJD 55882. The observed gamma-ray emission is characterised by a moderate 0.2-300 GeV flux F(0.2-300 GeV)=$(8.22\pm2.04)\times10^{-9}$ ph cm$^{-2}$s$^{-1}$ and a hard power law spectrum with spectral index $\Gamma=1.76\pm0.09$. These properties appear consistent with the known sub-population of TeV gamma-ray-emitting BL Lac objects, implying that the source may be detectable using atmospheric Cherenkov telescope arrays. Moreover, the temporal variability of the source suggests that real-time searches of the Fermi-LAT all-sky dataset for weak emission on ~200 day timescales may represent a rewarding strategy.Comment: 5 pages, 4 figures. Accepted for publication in Astronomy & Astrophysic

Search for Gamma-ray Line Signatures with H.E.S.S

Many results from astrophysical observations point to a 27% contribution of non-baryonic dark matter to the mass-energy budget of the universe. Although still elusive, strongly motivated candidates in form of weakly interacting massive particles could explain the nature of dark matter, and their annihilation or decay would give rise to detectable signatures in gamma-rays. In 2012, the H.E.S.S. collaboration started taking data with the largest imaging atmospheric Cherenkov telescope in the world which significantly lowered the energy threshold of the already operational four-telescope system. In particular, due to its location and improved performance at low energies, the H.E.S.S. experiment is now in a position to extend the search for dark matter line signals down to the 100 GeV mass range. The sensitivity to line searches with a new full likelihood approach will be discussed and preliminary results from observations with the second phase of H.E.S.S. will be presented.Comment: ICRC 2015 Conference Proceeding, 8 pages, 5 figures, 1 tabl

Direct Constraints on Minimal Supersymmetry from Fermi-LAT Observations of the Dwarf Galaxy Segue 1

The dwarf galaxy Segue 1 is one of the most promising targets for the indirect detection of dark matter. Here we examine what constraints 9 months of Fermi-LAT gamma-ray observations of Segue 1 place upon the Constrained Minimal Supersymmetric Standard Model (CMSSM), with the lightest neutralino as the dark matter particle. We use nested sampling to explore the CMSSM parameter space, simultaneously fitting other relevant constraints from accelerator bounds, the relic density, electroweak precision observables, the anomalous magnetic moment of the muon and B-physics. We include spectral and spatial fits to the Fermi observations, a full treatment of the instrumental response and its related uncertainty, and detailed background models. We also perform an extrapolation to 5 years of observations, assuming no signal is observed from Segue 1 in that time. Results marginally disfavour models with low neutralino masses and high annihilation cross-sections. Virtually all of these models are however already disfavoured by existing experimental or relic density constraints.Comment: 22 pages, 5 figures; added extra scans with extreme halo parameters, expanded introduction and discussion in response to referee's comment

Investigating Gamma-Ray Lines from Dark Matter with Future Observatories

We study the prospects for studying line features in gamma-ray spectra with upcoming gamma-ray experiments, such as HESS-II, the Cherenkov Telescope Array (CTA), and the GAMMA-400 satellite. As an example we use the narrow feature at 130 GeV seen in public data from the Fermi-LAT satellite. We found that all three experiments should be able to confidently confirm or rule out the presence of this 130 GeV feature. If it is real, it should be confirmed with a confidence level higher than 5 sigma. Assuming it to be a spectral signature of dark matter origin, GAMMA-400, thanks to a projected energy resolution of about 1.5% at 100 GeV, should also be able to resolve both the \gamma\gamma-line and a corresponding Z\gamma- or H\gamma-feature, if the corresponding branching ratio is comparable to that into two photons. It will also allow to distinguish between a gamma-ray line and the similar feature resulting from internal bremsstrahlung photons.Comment: 12 pages, 6 figures, 1 tabl

Gamma-ray and radio properties of six pulsars detected by the fermi large area telescope

We report the detection of pulsed γ-rays for PSRs J0631+1036, J0659+1414, J0742-2822, J1420-6048, J1509-5850, and J1718-3825 using the Large Area Telescope on board the Fermi Gamma-ray Space Telescope (formerly known as GLAST). Although these six pulsars are diverse in terms of their spin parameters, they share an important feature: their γ-ray light curves are (at least given the current count statistics) single peaked. For two pulsars, there are hints for a double-peaked structure in the light curves. The shapes of the observed light curves of this group of pulsars are discussed in the light of models for which the emission originates from high up in the magnetosphere. The observed phases of the γ-ray light curves are, in general, consistent with those predicted by high-altitude models, although we speculate that the γ-ray emission of PSR J0659+1414, possibly featuring the softest spectrum of all Fermi pulsars coupled with a very low efficiency, arises from relatively low down in the magnetosphere. High-quality radio polarization data are available showing that all but one have a high degree of linear polarization. This allows us to place some constraints on the viewing geometry and aids the comparison of the γ-ray light curves with high-energy beam models

Complémentarité de recherche de matière noire dans les galaxies naines sphéroïdes avec les expériences H.E.S.S. et Fermi-LAT

In the current cosmological model, the Universe is predominantly composed of dark matter, the nature of which remains unexplained by the Standard Model of particle physic. Annihilation of particles of within new theoretical frameworks might induce a very high energy gamma-ray signal, observable by gamma-ray astronomy experiments. Largely dark matter dominated, dwarf spheroidal galaxies are privileged targets for such indirect search. The H.E.S.S. telescopes network discussed in the rst part of this work is a perfect example of atmospheric stereoscopic imaging experiment allowing to search for dark matter. A new discrimination method between electromagnetic and hadronic showers enhancing searches of weak sources is presented. It is applied to the Sagittarius dwarf galaxy observation data and the upper limit on the incoming gamma-ray ux is calculated. In orbit aboard Fermi's satellite since June 2008, the LAT conversion pair telecope enable dark matter search on the whole sky. Theoretical sensitivity to detect a dark matter signal is determined for two specic galaxies. At the end of the rst year of observations, upper limits on gamma-ray fluxes are derived for a catalog of dwarf spheroidal galaxies. Models of physic beyond the Standard Model are compared with calculated constraints on annihilation cross sections function of the mass paricles obtained from observations made with both experiments.Dans le modèle cosmologique actuel, l'Univers est majoritairement composé de matière noire dont la nature est inexpliquée par le Modèle Standard de la physique des particules. L'annihilation de particules issues de nouveaux cadres théoriques, peut induire un signal de rayons gamma de très hautes énergies, observable par des expériences d'astronomie gamma. Largement dominées par la matière noire, les galaxies naines sphéroïdes sont des cibles privilégiées pour conduire cette recherche. Le réseau de télescopes H.E.S.S. discuté dans la première partie est un parfait exemple d'expérience d'imagerie atmosphérique stéréoscopique permettant de conduire la recherche de matière noire. Une nouvelle méthode de discrimination des gerbes électromagnétiques et hadroniques permettant d'améliorer la recherche de sources faibles est présentée. Elle est appliquée aux données des observations de la galaxie naine du Sagittaire et la limite supérieure sur le flux de gamma en provenance de cet objet est calculée. En orbite à bord du satellite Fermi depuis Juin 2008, le télescope à conversion de paire LAT permet de rechercher la matière noire sur l'ensemble de la voûte céleste. La sensibilité théorique à détecter un signal de matière noire est déterminée pour deux galaxies naines spéciques. Au terme de la première année d'observations, les limites supérieures sur les ux de gamma sont dérivées pour un catalogue de galaxies naines sphéroïdes. Des modèles de physique au-delà du Modèle Standard sont confrontés avec les contraintes calculées sur les sections ecaces d'annihilation en fonction de la masse des particules obtenues à partir des observations effectuées avec ces deux expériences

Vida y Ética Año 8, Nº 1, 2007 (número completo)

Contenido: Editorial -- La educación en el amor : un proyecto que integra a la familia, la escuela y los alumnos / Luis Alfredo Anaya -- Limitación del esfuerzo terapéutico en neonatología / María Estela Grzona -- La homosexualidad en la cultura occidental : evolución histórica y perspectivas en el siglo XXI / María Mercedes Ferreier Farnier, Christian Schnake Silva -- Crisis en la enseñanza de la medicina / Marta Fracapani de Cuitiño -- La llamada "Obejeción de conciencia institucional" / Juan G. Navarro Floria -- Así entró el aborto en España / Francisco José Ballesta Ballester -- Objeción de conciencia / Fermín García Marcos -- Documentos Nacionales -- Documentos Internacionale

Fryns type mesomelic dysplasia of the upper limbs caused by inverted duplications of the HOXD gene cluster

The HoxD cluster is critical for vertebrate limb development. Enhancers located in both the telomeric and centromeric gene deserts flanking the cluster regulate the transcription of HoxD genes. In rare patients, duplications, balanced translocations or inversions misregulating HOXD genes are responsible for mesomelic dysplasia of the upper and lower limbs. By aCGH, whole-genome mate-pair sequencing, long-range PCR and fiber fluorescent in situ hybridization, we studied patients from two families displaying mesomelic dysplasia limited to the upper limbs. We identified microduplications including the HOXD cluster and showed that microduplications were in an inverted orientation and inserted between the HOXD cluster and the telomeric enhancers. Our results highlight the existence of an autosomal dominant condition consisting of isolated ulnar dysplasia caused by microduplications inserted between the HOXD cluster and the telomeric enhancers. The duplications likely disconnect the HOXD9 to HOXD11 genes from their regulatory sequences. This presumptive loss-of-function may have contributed to the phenotype. In both cases, however, these rearrangements brought HOXD13 closer to telomeric enhancers, suggesting that the alterations derive from the dominant-negative effect of this digit-specific protein when ectopically expressed during the early development of forearms, through the disruption of topologically associating domain structure at the HOXD locus

Efficacy and Safety of Alirocumab in Reducing Lipids and Cardiovascular Events

International audienceBackground Alirocumab, a monoclonal antibody that inhibits proprotein convertase subtilisin–kexin type 9 (PCSK9), has been shown to reduce low-density lipoprotein (LDL) cholesterol levels in patients who are receiving statin therapy. Larger and longer-term studies are needed to establish safety and efficacy. Methods We conducted a randomized trial involving 2341 patients at high risk for cardiovascular events who had LDL cholesterol levels of 70 mg per deciliter (1.8 mmol per liter) or more and were receiving treatment with statins at the maximum tolerated dose (the highest dose associated with an acceptable side-effect profile), with or without other lipid-lowering therapy. Patients were randomly assigned in a 2:1 ratio to receive alirocumab (150 mg) or placebo as a 1-ml subcutaneous injection every 2 weeks for 78 weeks. The primary efficacy end point was the percentage change in calculated LDL cholesterol level from baseline to week 24. Results At week 24, the difference between the alirocumab and placebo groups in the mean percentage change from baseline in calculated LDL cholesterol level was −62 percentage points (P<0.001); the treatment effect remained consistent over a period of 78 weeks. The alirocumab group, as compared with the placebo group, had higher rates of injection-site reactions (5.9% vs. 4.2%), myalgia (5.4% vs. 2.9%), neurocognitive events (1.2% vs. 0.5%), and ophthalmologic events (2.9% vs. 1.9%). In a post hoc analysis, the rate of major adverse cardiovascular events (death from coronary heart disease, nonfatal myocardial infarction, fatal or nonfatal ischemic stroke, or unstable angina requiring hospitalization) was lower with alirocumab than with placebo (1.7% vs. 3.3%; hazard ratio, 0.52; 95% confidence interval, 0.31 to 0.90; nominal P=0.02). Conclusions Over a period of 78 weeks, alirocumab, when added to statin therapy at the maximum tolerated dose, significantly reduced LDL cholesterol levels. In a post hoc analysis, there was evidence of a reduction in the rate of cardiovascular events with alirocumab. (Funded by Sanofi and Regeneron Pharmaceuticals