285 research outputs found
Long-term psychosocial functioning after Ilizarov limb lengthening during childhood: 37 patients followed for 2â14 years
Background and purpose Few studies have been concerned with the patient's perception of the outcome of limb lengthening. We describe the psychological and social functioning after at least 2 years of follow-up in patients who had had a leg length discrepancy and who had undergone an Ilizarov limb lengthening procedure
Discovery of VHE Gamma Radiation from IC443 with the MAGIC Telescope
We report the detection of a new source of very high energy (VHE, E_gamma >=
100GeV) gamma-ray emission located close to the Galactic Plane, MAGIC
J0616+225, which is spatially coincident with SNR IC443. The observations were
carried out with the MAGIC telescope in the periods December 2005 - January
2006 and December 2006 - January 2007. Here we present results from this
source, leading to a VHE gamma-ray signal with a statistical significance of
5.7 sigma in the 2006/7 data and a measured differential gamma-ray flux
consistent with a power law, described as dN_gamma/(dA dt dE) = (1.0 +/-
0.2)*10^(-11)(E/0.4 TeV)^(-3.1 +/- 0.3) cm^(-2)s^(-1)TeV^(-1). We briefly
discuss the observational technique used and the procedure implemented for the
data analysis. The results are put in the perspective of the multiwavelength
emission and the molecular environment found in the region of IC443.Comment: Accepted by ApJ Letter
Search for gamma-ray emission from magnetars with the Fermi Large Area Telescope
We report on the search for 0.1-10 GeV emission from magnetars in 17 months
of Fermi Large Area Telescope (LAT) observations. No significant evidence for
gamma-ray emission from any of the currently-known magnetars is found. The most
stringent upper limits to date on their persistent emission in the Fermi-LAT
energy range are estimated between ~10^{-12}-10^{-10} erg/s/cm2, depending on
the source. We also searched for gamma-ray pulsations and possible outbursts,
also with no significant detection. The upper limits derived support the
presence of a cut-off at an energy below a few MeV in the persistent emission
of magnetars. They also show the likely need for a revision of current models
of outer gap emission from strongly magnetized pulsars, which, in some
realizations, predict detectable GeV emission from magnetars at flux levels
exceeding the upper limits identified here using the Fermi-LAT observations.Comment: ApJ Letters in press; Corresponding authors: Caliandro G. A., Hadasch
D., Rea N., Burnett
Detection of Gamma-Ray Emission from the Starburst Galaxies M82 and NGC 253 with the Large Area Telescope on Fermi
We report the detection of high-energy gamma-ray emission from two starburst
galaxies using data obtained with the Large Area Telescope on board the Fermi
Gamma-ray Space Telescope. Steady point-like emission above 200 MeV has been
detected at significance levels of 6.8 sigma and 4.8 sigma respectively, from
sources positionally coincident with locations of the starburst galaxies M82
and NGC 253. The total fluxes of the sources are consistent with gamma-ray
emission originating from the interaction of cosmic rays with local
interstellar gas and radiation fields and constitute evidence for a link
between massive star formation and gamma-ray emission in star-forming galaxies.Comment: Submitted to ApJ Letter
Fermi Gamma-ray Imaging of a Radio Galaxy
The Fermi Gamma-ray Space Telescope has detected the gamma-ray glow emanating
from the giant radio lobes of the radio galaxy Centaurus A. The resolved
gamma-ray image shows the lobes clearly separated from the central active
source. In contrast to all other active galaxies detected so far in high-energy
gamma-rays, the lobe flux constitutes a considerable portion (>1/2) of the
total source emission. The gamma-ray emission from the lobes is interpreted as
inverse Compton scattered relic radiation from the cosmic microwave background
(CMB), with additional contribution at higher energies from the
infrared-to-optical extragalactic background light (EBL). These measurements
provide gamma-ray constraints on the magnetic field and particle energy content
in radio galaxy lobes, and a promising method to probe the cosmic relic photon
fields.Comment: 27 pages, includes Supplementary Online Material; corresponding
authors: C.C. Cheung, Y. Fukazawa, J. Knodlseder, L. Stawar
Fermi Large Area Telescope observations of PSR J1836+5925
The discovery of the gamma-ray pulsar PSR J1836+5925, powering the formerly
unidentified EGRET source 3EG J1835+5918, was one of the early accomplishments
of the Fermi Large Area Telescope (LAT). Sitting 25 degrees off the Galactic
plane, PSR J1836+5925 is a 173 ms pulsar with a characteristic age of 1.8
million years, a spindown luminosity of 1.1 erg s, and a
large off-peak emission component, making it quite unusual among the known
gamma-ray pulsar population. We present an analysis of one year of LAT data,
including an updated timing solution, detailed spectral results and a long-term
light curve showing no indication of variability. No evidence for a surrounding
pulsar wind nebula is seen and the spectral characteristics of the off-peak
emission indicate it is likely magnetospheric. Analysis of recent XMM
observations of the X-ray counterpart yields a detailed characterization of its
spectrum, which, like Geminga, is consistent with that of a neutron star
showing evidence for both magnetospheric and thermal emission.Comment: Accepted to Astrophysical Journa
A change in the optical polarization associated with a gamma-ray flare in the blazar 3C 279
It is widely accepted that strong and variable radiation detected over all
accessible energy bands in a number of active galaxies arises from a
relativistic, Doppler-boosted jet pointing close to our line of sight. The size
of the emitting zone and the location of this region relative to the central
supermassive black hole are, however, poorly known, with estimates ranging from
light-hours to a light-year or more. Here we report the coincidence of a
gamma-ray flare with a dramatic change of optical polarization angle. This
provides evidence for co-spatiality of optical and gamma-ray emission regions
and indicates a highly ordered jet magnetic field. The results also require a
non-axisymmetric structure of the emission zone, implying a curved trajectory
for the emitting material within the jet, with the dissipation region located
at a considerable distance from the black hole, at about 10^5 gravitational
radii.Comment: Published in Nature issued on 18 February 2010. Corresponding
authors: Masaaki Hayashida and Greg Madejsk
Molecular Refinement of Clinical Staging in Hepatocellular Carcinoma Patients Evaluated for Potentially Curative Therapies
Abstract: Aim: VEGF and AFP mRNA determinations in the blood are promising prognostic factors for patients with HCC. This study explores their potential prognostic synergy in a cohort of HCC patients evaluated for potentially curative therapies.
Methods: One hundred twenty-four patients with a diagnosis of HCC were prospectively enrolled in the study. Inclusion criteria were: (a) histological diagnosis of HCC and assessment of tumour grade and (b) determination of AFP mRNA status and VEGF levels in the blood before therapy.
Results: At baseline evaluation, 40% of the study group had AFP mRNA in the blood (AFP mRNA positive), and 35% had VEGF > 23 pg ml(-1) (VEGF positive). Surgery was performed in 58 patients (47%), 54 (43%) had tumour ablation, and 12 had chemoembolisation (10%). Median follow-up and survival of the study group were 19 and 26 months (range, 1 to 60), respectively. The association of AFP mRNA and VEGF proved to be prognostically more accurate than their single use in discriminating the risk of death (ROC curve analysis) and survival probability (Cox analysis). In particular, we identified 3 main molecular stages (p < 0,0001): both negative (3-year survival = 63%), one positive (3-year survival = 40%), both positive (3-year survival = 16%). Multivariate analysis identified BCLC staging, surgery, and molecular staging as the most significant survival variables.
Conclusions: The preoperative determination of AFP mRNA status and VEGF may potentially refine the prognostic evaluation of HCC patients and improve the selection process for potentially curative therapies
Identification and Replication of Three Novel Myopia Common Susceptibility Gene Loci on Chromosome 3q26 using Linkage and Linkage Disequilibrium Mapping
Refractive error is a highly heritable quantitative trait responsible for considerable morbidity. Following an initial genome-wide linkage study using microsatellite markers, we confirmed evidence for linkage to chromosome 3q26 and then conducted fine-scale association mapping using high-resolution linkage disequilibrium unit (LDU) maps. We used a preliminary discovery marker set across the 30-Mb region with an average SNP density of 1 SNP/15 kb (Map 1). Map 1 was divided into 51 LDU windows and additional SNPs were genotyped for six regions (Map 2) that showed preliminary evidence of multi-marker association using composite likelihood. A total of 575 cases and controls selected from the tails of the trait distribution were genotyped for the discovery sample. Malecot model estimates indicate three loci with putative common functional variants centred on MFN1 (180,566 kb; 95% confidence interval 180,505â180, 655 kb), approximately 156 kb upstream from alternate-splicing SOX2OT (182,595 kb; 95% CI 182,533â182,688 kb) and PSARL (184,386 kb; 95% CI 184,356â184,411 kb), with the loci showing modest to strong evidence of association for the Map 2 discovery samples (p<10â7, p<10â10, and pâ=â0.01, respectively). Using an unselected independent sample of 1,430 individuals, results replicated for the MFN1 (pâ=â0.006), SOX2OT (pâ=â0.0002), and PSARL (pâ=â0.0005) gene regions. MFN1 and PSARL both interact with OPA1 to regulate mitochondrial fusion and the inhibition of mitochondrial-led apoptosis, respectively. That two mitochondrial regulatory processes in the retina are implicated in the aetiology of myopia is surprising and is likely to provide novel insight into the molecular genetic basis of common myopia
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