La paralysie obstétricale du nouveau-né n’a pas disparu malgré les importants progrès de l’obstétrique. Un nombre élevé de ces paralysies récupèrent spontanément mais une minorité nécessitent un ...traitement chirurgical. Depuis 27 ans, nous avons exploré et réparé 732 plexus brachiaux chez des nourrissons n’ayant pas récupéré le biceps après trois mois. La réparation était toujours possible et ses résultats ont été largement meilleurs que l’évolution spontanée. Ces résultats sont présentés avec un recul dépassant 20 ans pour certains patients. Ils confirment l’intérêt de l’abord précoce du plexus.
Obstetrical paralysis of the brachial plexus has not disappeared despite constant improvements in obstetrical care. Many of these paralyses recover spontaneously but a minority will need surgical repair. Since 27 years we have explored and repaired 732 plexuses in newborns who have not recovered the biceps function at 3 months. Repair was always possible and the results have been largely superior to spontaneous recovery. We present these results with a follow-up over 20 years for some patients. They confirm the advantages of early exploration of the brachial plexus.
We report the Fermi Large Area Telescope (LAT) detections of high-energy (>100 MeV) γ -ray emission from two recent optically bright classical novae, V1369 Centauri 2013 and V5668 Sagittarii 2015. At ...early times, Fermi target-of-opportunity observations prompted by their optical discoveries provided enhanced LAT exposure that enabled the detections of γ -ray onsets beginning ∼2 days after their first optical peaks. Significant γ -ray emission was found extending to 39–55 days after their initial LAT detections, with systematically fainter and longer-duration emission compared to previous γ -ray-detected classical novae. These novae were distinguished by multiple bright optical peaks that encompassed the time spans of the observed γ -rays. The γ -ray light curves and spectra of the two novae are presented along with representative hadronic and leptonic models, and comparisons with other novae detected by the LAT are discussed.
ABSTRACT We report the discovery of PSR J1906+0722, a gamma-ray pulsar detected as part of a blind survey of unidentified Fermi Large Area Telescope (LAT) sources being carried out on the volunteer ...distributed computing system, Einstein@Home. This newly discovered pulsar previously appeared as the most significant remaining unidentified gamma-ray source without a known association in the second Fermi-LAT source catalog (2FGL) and was among the top 10 most significant unassociated sources in the recent third catalog (3FGL). PSR J1906+0722 is a young, energetic, isolated pulsar, with a spin frequency of 8.9 Hz, a characteristic age of 49 kyr, and spin-down power erg s−1. In 2009 August it suffered one of the largest glitches detected from a gamma-ray pulsar ( ). Remaining undetected in dedicated radio follow-up observations, the pulsar is likely radio-quiet. An off-pulse analysis of the gamma-ray flux from the location of PSR J1906+0722 revealed the presence of an additional nearby source, which may be emission from the interaction between a neighboring supernova remnant and a molecular cloud. We discuss possible effects which may have hindered the detection of PSR J1906+0722 in previous searches and describe the methods by which these effects were mitigated in this survey. We also demonstrate the use of advanced timing methods for estimating the positional, spin and glitch parameters of difficult-to-time pulsars such as this.
We present the analysis of Fermi Large Area Telescope γ-ray observations of HB 21 (G89.0+4.7). We detect significant γ-ray emission associated with the remnant: the flux >100 MeV is 9.4 ± 0.8 (stat) ...± 1.6 (syst) × 10{sup –11} erg cm{sup –2} s{sup –1}. HB 21 is well modeled by a uniform disk centered at l = 88.°75 ± 0.°04, b = +4.°65 ± 0.°06 with a radius of 1.°19 ± 0.°06. The γ-ray spectrum shows clear evidence of curvature, suggesting a cutoff or break in the underlying particle population at an energy of a few GeV. We complement γ-ray observations with the analysis of the WMAP 7 yr data from 23 to 93 GHz, achieving the first detection of HB 21 at these frequencies. In combination with archival radio data, the radio spectrum shows a spectral break, which helps to constrain the relativistic electron spectrum, and, in turn, parameters of simple non-thermal radiation models. In one-zone models multiwavelength data favor the origin of γ rays from nucleon-nucleon collisions. A single population of electrons cannot produce both γ rays through bremsstrahlung and radio emission through synchrotron radiation. A predominantly inverse-Compton origin of the γ-ray emission is disfavored because it requires lower interstellar densities than are inferred for HB 21. In the hadronic-dominated scenarios, accelerated nuclei contribute a total energy of ∼3 × 10{sup 49} erg, while, in a two-zone bremsstrahlung-dominated scenario, the total energy in accelerated particles is ∼1 × 10{sup 49} erg.
Observations of occultations of bright gamma-ray sources by the Sun may reveal predicted pair halos around blazars and/or new physics, such as, e.g., hypothetical light dark matter particles-axions. ...We use Fermi Gamma-Ray Space Telescope (Fermi) data to analyze four occultations of blazar 3C 279 by the Sun on October 8 each year from 2008 to 2011. A combined analysis of the observations of these occultations allows a point-like source at the position of 3C 279 to be detected with significance of approximately 3sigma, but does not reveal any significant excess over the flux expected from the quiescent Sun. The likelihood ratio test rules out complete transparency of the Sun to the blazar gamma-ray emission at a 3sigma confidence level.
Gamma-ray binaries are stellar systems for which the spectral energy distribution (discounting the thermal stellar emission) peaks at high energies. Detected from radio to TeV gamma rays, the ...gamma-ray binary LS I + 61 degrees 303 is highly variable across all frequencies. One aspect of this system's variability is the modulation of its emission with the timescale set by the similar to 26.4960 day orbital period. Here we show that, during the time of our observations, the gamma-ray emission of LS I + 61 degrees 303 also presents a sinusoidal variability consistent with the previously known superorbital period of 1667 days. This modulation is more prominently seen at orbital phases around apastron, whereas it does not introduce a visible change close to periastron. It is also found in the appearance and disappearance of variability at the orbital period in the power spectrum of the data. This behavior could be explained by a quasi-cyclical evolution of the equatorial outflow of the Be companion star, whose features influence the conditions for generating gamma rays. These findings open the possibility to use gamma-ray observations to study the outflows of massive stars in eccentric binary systems.
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