2,264 research outputs found
Effect of supervised exercise on physical function and balance in patients with intermittent claudication
Background The aim of the study was to identify whether a standard supervised exercise programme (SEP) for patients with intermittent claudication improved specific measures of functional performance including balance. Methods A prospective observational study was performed at a single tertiary vascular centre. Patients with symptomatic intermittent claudication (Rutherford grades 1–3) were recruited to the study. Participants were assessed at baseline (before SEP) and 3, 6 and 12 months afterwards for markers of lower-limb ischaemia (treadmill walking distance and ankle : brachial pressure index), physical function (6-min walk, Timed Up and Go test, and Short Physical Performance Battery (SPPB) score), balance impairment using computerized dynamic posturography with the Sensory Organization Test (SOT), and quality of life (VascuQoL and Short Form 36). Results Fifty-one participants underwent SEP, which significantly improved initial treadmill walking distance (P = 0·001). Enrolment in a SEP also resulted in improvements in physical function as determined by 6-min maximum walking distance (P = 0·006), SPPB score (P < 0·001), and some domains of both generic (bodily pain, P = 0·025) and disease-specific (social domain, P = 0·039) quality of life. Significant improvements were also noted in balance, as determined by the SOT (P < 0·001). Conclusion Supervised exercise improves both physical function and balance impairment
Target of Opportunity Observations of Gravitational Wave Events with LSST
The discovery of the electromagnetic counterparts to the binary neutron star merger GW170817 has opened the era of GW+EM multi-messenger astronomy. Exploiting this breakthrough requires increasing samples to explore the diversity of kilonova behaviour and provide more stringent constraints on the Hubble constant, and tests of fundamental physics. LSST can play a key role in this field in the 2020s, when the gravitational wave detector network is expected to detect higher rates of merger events involving neutron stars (∼10s per year) out to distances of several hundred Mpc. Here we propose comprehensive target-of-opportunity (ToOs) strategies for follow-up of gravitational-wave sources that will make LSST the premiere machine for discovery and early characterization for neutron star mergers and other gravitational-wave sources
Quantifying modeling uncertainties when combining multiple gravitational-wave detections from binary neutron star sources
With the increasing sensitivity of gravitational-wave detectors, we expect to observe multiple binary neutron-star systems through gravitational waves in the near future. The combined analysis of these gravitational-wave signals offers the possibility to constrain the neutron-star radius and the equation of state of dense nuclear matter with unprecedented accuracy. However, it is crucial to ensure that uncertainties inherent in the gravitational-wave models will not lead to systematic biases when information from multiple detections are combined. To quantify waveform systematics, we perform an extensive simulation campaign of binary neutron-star sources and analyse them with a set of four different waveform models. Based on our analysis with about 38 simulations, we find that statistical uncertainties in the neutron-star radius decrease to ( at credible interval) but that systematic differences between currently employed waveform models can be twice as large. Hence, it will be essential to ensure that systematic biases will not become dominant in inferences of the neutron-star equation of state when capitalizing on future developments
Low-Mass Eclipsing Binaries in the Initial Kepler Data Release
We identify 231 objects in the newly released Cycle 0 dataset from the Kepler
Mission as double-eclipse, detached eclipsing binary systems with Teff < 5500 K
and orbital periods shorter than ~32 days. We model each light curve using the
JKTEBOP code with a genetic algorithm to obtain precise values for each system.
We identify 95 new systems with both components below 1.0 M_sun and eclipses of
at least 0.1 magnitudes, suitable for ground-based follow-up. Of these, 14 have
periods less than 1.0 day, 52 have periods between 1.0 and 10.0 days, and 29
have periods greater than 10.0 days. This new sample of main-sequence,
low-mass, double-eclipse, detached eclipsing binary candidates more than
doubles the number of previously known systems, and extends the sample into the
completely heretofore unexplored P > 10.0 day period regime. We find
preliminary evidence from these systems that the radii of low-mass stars in
binary systems decrease with period. This supports the theory that binary
spin-up is the primary cause of inflated radii in low-mass binary systems,
although a full analysis of each system with radial-velocity and multi-color
light curves is needed to fully explore this hypothesis. As well, we present 7
new transiting planet candidates that do not appear among the recently released
list of 706 candidates by the Kepler team, nor in the Kepler False Positive
Catalog, along with several other new and interesting systems. We also present
novel techniques for the identification, period analysis, and modeling of
eclipsing binaries.Comment: 22 pages in emulateapj format. 9 figures, 4 tables, 2 appendices.
Accepted to AJ. Includes a significant addition of new material since last
arXiv submission and an updated method for estimating masses and radi
Gravity and Light: Combining Gravitational Wave and Electromagnetic Observations in the 2020s
As of today, we have directly detected exactly one source in both gravitational waves (GWs) and electromagnetic (EM) radiation, the binary neutron star merger GW170817, its associated gamma-ray burst GRB170817A, and the subsequent kilonova SSS17a/AT 2017gfo. Within ten years, we will detect hundreds of events, including new classes of events such as neutron-star-black-hole mergers, core-collapse supernovae, and almost certainly something completely unexpected. As we build this sample, we will explore exotic astrophysical topics ranging from nucleosynthesis, stellar evolution, general relativity, high-energy astrophysics, nuclear matter, to cosmology. The discovery potential is extraordinary, and investments in this area will yield major scientific breakthroughs. Here we outline some of the most exciting scientific questions that can be answered by combining GW and EM observations
Promoting Colorectal Cancer Screening Among Haitian Americans
Background: Few studies have examined colorectal cancer screening among Haitian Americans, although striking disparities in colorectal cancer screening and mortality are well-documented among U.S. Blacks. Race, socioeconomic status, and place of birth are factors associated with colorectal cancer incidence and mortality patterns.
Methods: In this article, we summarize published studies on colorectal cancer screening among Haitian Americans, identified through bibliographic searches in PubMed and CINAHL through August 2015, and offer recommendations for further research.
Results: Only one qualitative study and three quantitative surveys have examined colorectal cancer screening among Haitian Americans. A qualitative study found important differences in perceptions of the curability of colorectal cancer, preventive practices, and preferred sources of information among Haitian Americans and other ethnic subgroups of U.S. Blacks. Awareness of colorectal cancer screening tests, risk perception, healthcare provider recommendation, and self-reported use of screening are suboptimal among Haitian Americans and other subgroups. In preliminary quantitative studies, Haitian immigrants have been found to have lower colorectal cancer screening rates than other groups such as African Americans.
Conclusions: Culturally appropriate educational interventions are needed to encourage Haitian American adults aged \u3e 50 years to undergo screening for colorectal cancer and to ensure that they are well informed about the value of healthy eating and physical activity
Nuclear Physics Multimessenger Astrophysics Constraints on the Neutron Star Equation of State: Adding NICER's PSR J0740+6620 Measurement
In the past few years, new observations of neutron stars (NSs) and NS mergers have provided a wealth of data that allow one to constrain the equation of state (EOS) of nuclear matter at densities above nuclear saturation density. However, most observations were based on NSs with masses of about 1.4 M⊙, probing densities up to ∼three to four times the nuclear saturation density. Even higher densities are probed inside massive NSs such as PSR J0740+6620. Very recently, new radio observations provided an update to the mass estimate for PSR J0740+6620, and X-ray observations by the NICER and XMM telescopes constrained its radius. Based on these new measurements, we revisit our previous nuclear physics multimessenger astrophysics constraints and derive updated constraints on the EOS describing the NS interior. By combining astrophysical observations of two radio pulsars, two NICER measurements, the two gravitational-wave detections GW170817 and GW190425, detailed modeling of the kilonova AT 2017gfo, and the gamma-ray burst GRB 170817A, we are able to estimate the radius of a typical 1.4 M⊙ NS to be 11.94-0.87+0.76 km at 90% confidence. Our analysis allows us to revisit the upper bound on the maximum mass of NSs and disfavors the presence of a strong first-order phase transition from nuclear matter to exotic forms of matter, such as quark matter, inside NSs
Target of Opportunity Observations of Gravitational Wave Events with LSST
The discovery of the electromagnetic counterparts to the binary neutron star merger GW170817 has opened the era of GW+EM multi-messenger astronomy. Exploiting this breakthrough requires increasing samples to explore the diversity of kilonova behaviour and provide more stringent constraints on the Hubble constant, and tests of fundamental physics. LSST can play a key role in this field in the 2020s, when the gravitational wave detector network is expected to detect higher rates of merger events involving neutron stars (∼10s per year) out to distances of several hundred Mpc. Here we propose comprehensive target-of-opportunity (ToOs) strategies for follow-up of gravitational-wave sources that will make LSST the premiere machine for discovery and early characterization for neutron star mergers and other gravitational-wave sources
Supplement: Going the Distance: Mapping Host Galaxies of LIGO and Virgo Sources in Three Dimensions Using Local Cosmography and Targeted Follow-up
This is a supplement to the Letter of Singer et al.
(https://arxiv.org/abs/1603.07333), in which we demonstrated a rapid algorithm
for obtaining joint 3D estimates of sky location and luminosity distance from
observations of binary neutron star mergers with Advanced LIGO and Virgo. We
argued that combining the reconstructed volumes with positions and redshifts of
possible host galaxies can provide large-aperture but small field of view
instruments with a manageable list of targets to search for optical or infrared
emission. In this Supplement, we document the new HEALPix-based file format for
3D localizations of gravitational-wave transients. We include Python sample
code to show the reader how to perform simple manipulations of the 3D sky maps
and extract ranked lists of likely host galaxies. Finally, we include
mathematical details of the rapid volume reconstruction algorithm.Comment: For associated data release, see
http://asd.gsfc.nasa.gov/Leo.Singer/going-the-distanc
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