3,086 research outputs found
NuSTAR discovery of an unusually steady long-term spin-up of the Be binary 2RXP J130159.6-635806
We present spectral and timing analysis of NuSTAR observations of the
accreting X-ray pulsar 2RXP J130159.6-635806. The source was serendipitously
observed during a campaign focused on the gamma-ray binary PSR B1259-63 and was
later targeted for a dedicated observation. The spectrum has a typical shape
for accreting X-ray pulsars, consisting of a simple power law with an
exponential cutoff starting at ~7 keV with a folding energy of E_fold=~18 keV.
There is also an indication of the presence of a 6.4 keV iron line in the
spectrum at the ~3 sigma significance level. NuSTAR measurements of the
pulsation period reveal that the pulsar has undergone a strong and steady
spin-up for the last 20 years. The pulsed fraction is estimated to be ~80%, and
is constant with energy up to 40 keV. The power density spectrum shows a break
towards higher frequencies relative to the current spin period. This, together
with steady persistent luminosity, points to a long-term mass accretion rate
high enough to bring the pulsar out of spin equilibrium.Comment: 13 pages, 7 figures, accepted for publication in The Astrophysical
Journa
NuSTAR Hard X-ray Survey of the Galactic Center Region I: Hard X-ray Morphology and Spectroscopy of the Diffuse Emission
We present the first sub-arcminute images of the Galactic Center above 10
keV, obtained with NuSTAR. NuSTAR resolves the hard X-ray source IGR
J17456-2901 into non-thermal X-ray filaments, molecular clouds, point sources
and a previously unknown central component of hard X-ray emission (CHXE).
NuSTAR detects four non-thermal X-ray filaments, extending the detection of
their power-law spectra with - up to ~50 keV. A
morphological and spectral study of the filaments suggests that their origin
may be heterogeneous, where previous studies suggested a common origin in young
pulsar wind nebulae (PWNe). NuSTAR detects non-thermal X-ray continuum emission
spatially correlated with the 6.4 keV Fe K fluorescence line emission
associated with two Sgr A molecular clouds: MC1 and the Bridge. Broad-band
X-ray spectral analysis with a Monte-Carlo based X-ray reflection model
self-consistently determined their intrinsic column density (
cm), primary X-ray spectra (power-laws with ) and set a
lower limit of the X-ray luminosity of Sgr A* flare illuminating the Sgr A
clouds to erg s. Above ~20 keV, hard
X-ray emission in the central 10 pc region around Sgr A* consists of the
candidate PWN G359.95-0.04 and the CHXE, possibly resulting from an unresolved
population of massive CVs with white dwarf masses . Spectral energy distribution analysis suggests that G359.95-0.04 is
likely the hard X-ray counterpart of the ultra-high gamma-ray source HESS
J1745-290, strongly favoring a leptonic origin of the GC TeV emission.Comment: 27 pages. Accepted for publication in the Astrophysical Journa
Improving the management of open tibia fractures, Malawi.
To assess the impact of an open fracture intervention bundle on clinical management and patient outcomes of adults in Malawi with open tibia fractures. We conducted a before-and-after implementation study in Malawi in 2021 and 2022 to assess the impact of an open fracture intervention bundle, including a national education course for clinical officers and management guidelines for open fractures. We recruited 287 patients with open tibia fractures. The primary outcome was a before-and-after comparison of the self-reported short musculoskeletal function assessment score, a measure of patient function. Secondary outcomes included clinical management; and clinician knowledge and implementation evaluation outcomes of 57 health-care providers attending the course. We also constructed multilevel regression models to investigate associations between clinical knowledge, patient function, and implementation evaluation before and after the intervention. The median patient function score at 1 year was 6.8 (interquartile range, IQR: 1.5 to 14.5) before intervention and 8.4 (IQR: 3.8 to 23.2) after intervention. Compared with baseline scores, we found clinicians' open fracture knowledge scores improved 1 year after the intervention was implemented (mean posterior difference: 1.6, 95% highest density interval: 0.9 to 2.4). However, we found no difference in most aspects of clinicians' open fracture management practice. Despite possible improvement in clinician knowledge and positive evaluation of the intervention implementation, our study showed that there was no overall improvement in clinical management, and weak evidence of worsening patient function 1 year after injury, after implementation of the open fracture intervention bundle
Functional outcomes and quality of life at 1-year follow-up after an open tibia fracture in Malawi: a multicentre, prospective cohort study
Background:
Injuries are a major cause of disability globally and injury incidence is rapidly increasing, largely due to road traffic injuries in low-income and middle-income countries. Current estimates of the scale and consequences of disability from injury are largely based on modelling studies, with a scarcity of empirical evidence from severe injuries in low-income countries. We aimed to better understand the outcomes for individuals with open tibia fractures in Malawi.
Methods:
In this multicentre, prospective cohort study, adults (aged ≥18 years) with open tibia fractures were systematically recruited at six hospitals in Malawi (two tertiary hospitals and four district hospitals). Follow-up lasted at least 1 year, during which in-person follow-up reviews were done at 6 weeks, 3 months, 6 months, and 1 year post-injury. The primary outcome was function at 1 year post-injury, measured by the Short Musculoskeletal Functional Assessment (SMFA) score. Secondary outcomes included quality-adjusted life-years (QALYs; as determined via the European Quality of Life 5-Dimensions 3-Levels [EQ-5D-3L] survey) and fracture-related infection at 1 year post-injury. Multilevel regression models investigated associations between SMFA score, EQ-5D-3L, baseline factors, and orthopaedic management.
Findings:
Between Feb 12, 2021, and March 14, 2022, 287 participants were enrolled (median age 34 years [IQR 25–44]; 84% male). The most common mode of injury was road traffic injuries (194 [68%] of 287). Overall, 268 (93%) participants had debridement; of the 63 participants who were debrided in district hospitals, 47 (75%) had the procedure under local or no anaesthesia. Following substantial declines by 6 weeks after injury, function and quality of life had not recovered by 1 year post-injury for participants with Gustilo grade I–II fractures (posterior mean SMFA at 1 year: 10·5, 95% highest density interval [HDI]: 9·5–11·6; QALYs: 0·73, 95% HDI: 0·66–0·80) nor Gustilo grade III fractures (posterior mean SMFA at 1 year: 14·9, 95% HDI: 13·4–16·6; QALYs: 0·67, 95% HDI: 0·59–0·75). For all fracture grades, intramedullary nailing substantially improved function and quality of life at 1 year post-injury. Delayed definitive fixation after 5 days had 5-times greater odds of infection compared with early management within 2 days (adjusted odds ratio: 5·1, 95% CI 1·8–16·1; p=0·02).
Interpretation:
Adults with open tibia fractures in Malawi have poor function and quality of life in the 1 year following injury. Centralised orthopaedic surgical management, including early definitive fixation and intramedullary nailing for more severe injuries, might improve outcomes.
Funding:
Wellcome Trust
Medical terminations of pregnancy: A viable source of tissue for cell replacement therapy for neurodegenerative disorders
“Proof-of-principle” that cell replacement therapy works for neurodegeneration has been reported, but only using donor cells collected from fetal brain tissue obtained from surgical terminations of pregnancy. Surgical terminations of pregnancy represent an increasingly limited supply of donor cells due to the tendency towards performing medical termination in much of Europe. This imposes a severe constraint on further experimental and clinical cell transplantation research. Therefore, we explore here the feasibility of using medical termination tissue as a donor source. Products of conception were retrieved from surgical terminations over the last 7 years and from medical terminations over the last 2.5 years. The number of collections that yielded fetal tissue, viable brain tissue, and identifiable brain regions (ganglionic eminence, ventral mesencephalon, and neocortex) were recorded. We studied cell viability, cell physiological properties, and differentiation potential both in vitro and following transplantation into the central nervous system of rodent models of neurodegenerative disease. Within equivalent periods, we were able to collect substantially greater numbers of fetal remains from medical than from surgical terminations of pregnancy, and the medical terminations yielded a much higher proportion of identifiable and dissectible brain tissue. Furthermore, we demonstrate that harvested cells retain the capacity to differentiate into neurons with characteristics appropriate to the region from which they are dissected. We show that, contrary to widespread assumption, medical termination of pregnancy-derived fetal brain cells represent a feasible and more readily available source of human fetal tissue for experimental cell transplantation with the potential for use in future clinical trials in human neurodegenerative disease
Catching Element Formation In The Act
Gamma-ray astronomy explores the most energetic photons in nature to address
some of the most pressing puzzles in contemporary astrophysics. It encompasses
a wide range of objects and phenomena: stars, supernovae, novae, neutron stars,
stellar-mass black holes, nucleosynthesis, the interstellar medium, cosmic rays
and relativistic-particle acceleration, and the evolution of galaxies. MeV
gamma-rays provide a unique probe of nuclear processes in astronomy, directly
measuring radioactive decay, nuclear de-excitation, and positron annihilation.
The substantial information carried by gamma-ray photons allows us to see
deeper into these objects, the bulk of the power is often emitted at gamma-ray
energies, and radioactivity provides a natural physical clock that adds unique
information. New science will be driven by time-domain population studies at
gamma-ray energies. This science is enabled by next-generation gamma-ray
instruments with one to two orders of magnitude better sensitivity, larger sky
coverage, and faster cadence than all previous gamma-ray instruments. This
transformative capability permits: (a) the accurate identification of the
gamma-ray emitting objects and correlations with observations taken at other
wavelengths and with other messengers; (b) construction of new gamma-ray maps
of the Milky Way and other nearby galaxies where extended regions are
distinguished from point sources; and (c) considerable serendipitous science of
scarce events -- nearby neutron star mergers, for example. Advances in
technology push the performance of new gamma-ray instruments to address a wide
set of astrophysical questions.Comment: 14 pages including 3 figure
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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