3,734 research outputs found
Can past gamma-ray bursts explain both INTEGRAL and ATIC/PAMELA/Fermi anomalies simultaneously?
Gamma-ray bursts (GRBs) have been invoked to explain both the 511 keV
emission from the galactic bulge and the high-energy positron excess inferred
from the ATIC, PAMELA, and Fermi data. While independent explanations can be
responsible for these phenomena, we explore the possibility of their common
GRB-related origin by modeling the GRB distribution and estimating the rates.
For an expected Milky Way long GRB rate, neither of the two signals is generic;
the local excess requires a 2% coincidence, while the signal from the galactic
center requires a 20% coincidence with respect to the timing of the latest GRB.
The simultaneous explanation requires a 0.4% coincidence. Considering the large
number of statistical "trials" created by multiple searches for new physics,
the coincidences of a few per cent cannot be dismissed as unlikely.
Alternatively, both phenomena can be explained by GRBs if the galactic rate is
higher than expected. We also show that a similar result is difficult to obtain
assuming a simplified short GRB distribution.Comment: 4 pages; version accepted for publicatio
Information for Nurses on Return to Sport After Periacetabular Osteotomy Surgery
The purpose of this study was to answer the following question: Does the amount of physical therapy after PAO surgery for hip dysplasia, impact the ability of a patient to return to sporting activities? PAO surgery refers to Periacetabular Osteotomy surgery; a corrective surgical technique for hip dysplasia that aims to preserve the hip, rather than replace it. This question was addressed using a mixed methods survey designed to collect qualitative and quantitative data regarding patient experiences after PAO surgery. The survey was posted on two different Facebook pages: Post-PAO Return to Sport and Young Hip Impingement/Dysplasia (FAI, THR, PAO) Support. A linear regression was performed to analyze the results of the data. The data did not show a relationship between the amount of physical therapy and the ability to return to sport following a PAO operation. However, the data did show that patients who used a mobility device for longer than 8 weeks were on average 24.5% more likely to return to sports within 9 months compared to patients who used a mobility device for less than 8 weeks (p=0.245). No other statistically significant results were found. During the literature review for this study, it was established that there is insufficient research conducted on rehabilitation after surgery for hip dysplasia
Testing patients with non-specific symptoms for antibodies against Borrelia burgdorferi sensu lato does not provide useful clinical information about their aetiology
AbstractThe aim of this study was to determine whether patients with antibodies against Borrelia burgdorferi sensu lato or who report a history of erythema migrans (EM) or tick bite are more likely to have non-specific symptoms such as musculoskeletal pain, fatigue, sensory disorder, and headache. The study group comprised 423 subjects with non-specific symptoms tested for antibodies against B. burgdorferi sensu lato between July 2012 and December 2014 because of suspicion of Lyme borreliosis (LB). Of these, 285 were females (67%) and 138 were males (33%); the median age was 53 years (range, 7–89 years). Patients with a confirmed diagnosis of LB and patients with a known underlying disease that could influence the development of the symptoms were excluded from the evaluation. Subjects were assigned to the seronegative group or to one of three seropositive groups, and the history of EM and tick bite was also recorded. Statistical analysis was performed with single chi-square tests of independence and multiple logistic regression models. No differences in the occurrence of non-specific symptoms were observed between patients grouped according to antibody status. A history of EM showed no significant effect on any of the non-specific symptoms. A history of tick bite was weakly correlated with joint pain and joint swelling (p <0.05). In conclusion, it is highly unlikely that the complaints are related to a previous infection with B. burgdorferi sensu lato. The results show that testing patients with non-specific symptoms for antibodies against B. burgdorferi sensu lato in the everyday clinical setting does not provide any useful information about their aetiology
Probing the Structure of Jet Driven Core-Collapse Supernova and Long Gamma Ray Burst Progenitors with High Energy Neutrinos
Times of arrival of high energy neutrinos encode information about their
sources. We demonstrate that the energy-dependence of the onset time of
neutrino emission in advancing relativistic jets can be used to extract
important information about the supernova/gamma-ray burst progenitor structure.
We examine this energy and time dependence for different supernova and
gamma-ray burst progenitors, including red and blue supergiants, helium cores,
Wolf-Rayet stars, and chemically homogeneous stars, with a variety of masses
and metallicities. For choked jets, we calculate the cutoff of observable
neutrino energies depending on the radius at which the jet is stalled. Further,
we exhibit how such energy and time dependence may be used to identify and
differentiate between progenitors, with as few as one or two observed events,
under favorable conditions
The Optical Gravitational Lensing Experiment. Catalog of stellar proper motions in the OGLE-II Galactic bulge fields
We present a proper motion (\mu) catalogue of 5,080,236 stars in 49 Optical
Gravitational Lensing Experiment II (OGLE-II) Galactic bulge (GB) fields,
covering a range of -11 deg. <l< 11 deg. and -6 deg. <b<3 deg., the total area
close to 11 square degrees. The proper motion measurements are based on 138 -
555 I-band images taken during four observing seasons: 1997-2000. The catalogue
stars are in the magnitude range 11 < I < 18 mag. In particular, the catalogue
includes Red Clump Giants (RCGs) and Red Giants in the GB, and main sequence
stars in the Galactic disc. The proper motions up to \mu = 500 mas/yr were
measured with the mean accuracy of 0.8-3.5 mas/yr, depending on the brightness
of a star. This catalogue may be useful for studying the kinematic of stars in
the GB and the Galactic disk.Comment: 13 pages, 16 figures, MNRAS in pres
- …