12,239 research outputs found
Risk factors for erectile dysfunction in a cohort of 108 477 Australian men
Objectives: To quantify relationships between erectile dysfunction (ED), ageing and health and lifestyle factors for men aged 45 years and older. Design: Cross-sectional, population-based study seeking data on health, sociodemographic and lifestyle facto
The nearby eclipsing stellar system delta Velorum - I. Origin of the infrared excess from VISIR and NACO imaging
- Context: The triple stellar system delta Vel system presents a significant
infrared excess, whose origin is still being debated. A large infrared bow
shock has been discovered using Spitzer/MIPS observations. Although it appears
as a significant contributor to the measured IR excess, the possibility exists
that a circumstellar IR excess is present around the stars of the system. -
Aims: The objective of the present VISIR and NACO observations is to identify
whether one of the stars of the delta Vel system presents a circumstellar
photometric excess in the thermal IR domain and to quantify it. - Methods: We
observed delta Vel using the imaging modes of the ESO/VLT instruments VISIR (in
BURST mode) and NACO to resolve the A-B system (0.6" separation) and obtain the
photometry of each star. We also obtained one NACO photometry epoch precisely
at the primary (annular) eclipse of delta Vel Aa by Ab. - Results: Our
photometric measurements with NACO (2.17 mic), complemented by the existing
visible photometry allowed us to reconstruct the spectral energy distribution
of the three stars. We then compared the VISIR photometry (8.6-12.8 mic) to the
expected photospheric emission from the three stars at the corresponding
wavelengths. - Conclusions: We can exclude the presence of a circumstellar
thermal infrared excess around delta Vel A or B down to a few percent level.
This supports the conclusions of Gaspar et al. (2008) that the IR excess of
delta Vel has an interstellar origin, although a cold circumstellar disk could
still be present. In addition, we derive the spectral types of the three stars
Aa, Ab, and B (respectively A2IV, A4V and F8V), and we estimate the age of the
system around 400-500 Myr.Comment: 8 pages, 9 figures, A&A, in pres
Using interpretative phenomenological analysis to inform physiotherapy practice: An introduction with reference to the lived experience of cerebellar ataxia
The attached file is a pre-published version of the full and final paper which can be found at the link below.This article has been made available through the Brunel Open Access Publishing Fund.Qualitative research methods that focus on the lived experience of people with health conditions are relatively
underutilised in physiotherapy research. This article aims to introduce interpretative phenomenological analysis
(IPA), a research methodology oriented toward exploring and understanding the experience of a particular
phenomenon (e.g., living with spinal cord injury or chronic pain, or being the carer of someone with a particular
health condition). Researchers using IPA try to find out how people make sense of their experiences and the
meanings they attach to them. The findings from IPA research are highly nuanced and offer a fine grained
understanding that can be used to contextualise existing quantitative research, to inform understanding of novel
or underresearched topics or, in their own right, to provoke a reappraisal of what is considered known about
a specified phenomenon. We advocate IPA as a useful and accessible approach to qualitative research that
can be used in the clinical setting to inform physiotherapy practice and the development of services from the
perspective of individuals with particular health conditions.This article is available through the Brunel Open Access Publishing Fund
Polarization and Strong Infra-Red Activity in Compressed Solid Hydrogen
Under a pressure of ~150 GPa solid molecular hydrogen undergoes a phase
transition accompanied by a dramatic rise in infra-red absorption in the vibron
frequency range. We use the Berry's phase approach to calculate the electric
polarization in several candidate structures finding large, anisotropic dynamic
charges and strongly IR-active vibron modes. The polarization is shown to be
greatly affected by the overlap between the molecules in the crystal, so that
the commonly used Clausius-Mossotti description in terms of polarizable,
non-overlapping molecular charge densities is inadequate already at low
pressures and even more so for the compressed solid.Comment: To appear in Phys. Rev. Let
Multiferroicity in an organic charge-transfer salt: Electric-dipole-driven magnetism
Multiferroics, showing simultaneous ordering of electrical and magnetic
degrees of freedom, are remarkable materials as seen from both the academic and
technological points of view. A prominent mechanism of multiferroicity is the
spin-driven ferroelectricity, often found in frustrated antiferromagnets with
helical spin order. There, similar to conventional ferroelectrics, the
electrical dipoles arise from an off-centre displacement of ions. However,
recently a different mechanism, namely purely electronic ferroelectricity,
where charge order breaks inversion symmetry, has attracted considerable
interest. Here we provide evidence for this exotic type of ferroelectricity,
accompanied by antiferromagnetic spin order, in a two-dimensional organic
charge-transfer salt, thus representing a new class of multiferroics. Quite
unexpectedly for electronic ferroelectrics, dipolar and spin order arise nearly
simultaneously. This can be ascribed to the loss of spin frustration induced by
the ferroelectric ordering. Hence, here the spin order is driven by the
ferroelectricity, in marked contrast to the spin-driven ferroelectricity in
helical magnets.Comment: 8 pages, 9 figures (including 4 pages and 6 figures in supplementary
information). Version 2 with minor errors corrected (legend of Fig. 3c and
definition of vectors e and Q
Statistics of selectively neutral genetic variation
Random models of evolution are instrumental in extracting rates of
microscopic evolutionary mechanisms from empirical observations on genetic
variation in genome sequences. In this context it is necessary to know the
statistical properties of empirical observables (such as the local homozygosity
for instance). Previous work relies on numerical results or assumes Gaussian
approximations for the corresponding distributions. In this paper we give an
analytical derivation of the statistical properties of the local homozygosity
and other empirical observables assuming selective neutrality. We find that
such distributions can be very non-Gaussian.Comment: 4 pages, 4 figure
Services just for men? Insights from a national study of the well men services pilots.
Men continue to have a lower life expectancy in most countries compared to women. Explanations of this gendered health inequality tend to focus on male risk taking, unhealthy lifestyle choices and resistance to seeking help from health services. In the period 2005-2008 the Scottish Government funded a nationwide community health promotion programme aimed at improving men's health, called Well Men Service Pilots (henceforth WMS)
Wannier-function description of the electronic polarization and infrared absorption of high-pressure hydrogen
We have constructed maximally-localized Wannier functions for prototype
structures of solid molecular hydrogen under pressure, starting from LDA and
tight-binding Bloch wave functions. Each occupied Wannier function can be
associated with two paired protons, defining a ``Wannier molecule''. The sum of
the dipole moments of these ``molecules'' always gives the correct macroscopic
polarization, even under strong compression, when the overlap between nearby
Wannier functions becomes significant. We find that at megabar pressures the
contributions to the dipoles arising from the overlapping tails of the Wannier
functions is very large. The strong vibron infrared absorption experimentally
observed in phase III, above ~ 150 GPa, is analyzed in terms of the
vibron-induced fluctuations of the Wannier dipoles. We decompose these
fluctuations into ``static'' and ``dynamical'' contributions, and find that at
such high densities the latter term, which increases much more steeply with
pressure, is dominant.Comment: 17 pages, two-column style with 14 postscript figures embedded. Uses
REVTEX and epsf macro
Reverse Semi-Combustion Driven by Titanium Dioxide-Ionic Liquid Hybrid Photocatalyst
EP/L015633/1 EP/K005138/1 CAPES (158804/2017/01-and 001 FAPERGS -16/2552-0000 18/2551-0000561-4 88887.195052/2018-00 CNPq :406260/2018-4 169462/2017-0 406750/2016-5 465454/2014-3 grant agreement No 810310Unprecedented metal-free photocatalytic CO2 conversion to CO (up to 228±48 ÎŒmol gâ1 hâ1) was displayed by TiO2@IL hybrid photocatalysts prepared by simple impregnation of commercially available P25-titanium dioxide with imidazolium-based ionic liquids (ILs). The high activity of TiO2@IL hybrid photocatalysts was mainly associated to (i) TiO2@IL red shift compared to the pure TiO2 absorption, and thus a modification of the TiO2 surface electronic structure; (ii) TiO2 with IL bearing imidazolate anions lowered the CO2 activation energy barrier. The reaction mechanism was postulated to occur via CO2 photoreduction to formate species by the imidazole/imidazole radical redox pair, yielding CO and water.publishersversionpublishe
Near-Infrared interferometry of Eta Carinae with high spatial and spectral resolution using the VLTI and the AMBER instrument
We present the first NIR spectro-interferometry of the LBV Eta Carinae. The K
band observations were performed with the AMBER instrument of the ESO Very
Large Telescope Interferometer using three 8.2m Unit Telescopes with baselines
from 42 to 89m. The aim of this work is to study the wavelength dependence of
Eta Car's optically thick wind region with a high spatial resolution of 5 mas
(11 AU) and high spectral resolution. The medium spectral resolution
observations (R=1,500) were performed in the wavelength range around both the
HeI 2.059 micron and the Br gamma 2.166 micron emission lines, the high
spectral resolution observations (R=12,000) only in the Br gamma line region.
In the K-band continuum, a diameter of 4.0 +/-0.2 mas (Gaussian FWHM, fit range
28-89m) was measured for Eta Car's optically thick wind region. If we fit
Hillier et al. (2001) model visibilities to the observed AMBER visibilities, we
obtain 50 % encircled-energy diameters of 4.2, 6.5 and 9.6mas in the 2.17
micron continuum, the HeI, and the Br gamma emission lines, respectively. In
the continuum near the Br gamma line, an elongation along a position angle of
120+/-15 degrees was found, consistent with previous VLTI/VINCI measurements by
van Boekel et al. (2003). We compare the measured visibilities with predictions
of the radiative transfer model of Hillier et al. (2001), finding good
agreement. Furthermore, we discuss the detectability of the hypothetical hot
binary companion. For the interpretation of the non-zero differential and
closure phases measured within the Br gamma line, we present a simple geometric
model of an inclined, latitude-dependent wind zone. Our observations support
theoretical models of anisotropic winds from fast-rotating, luminous hot stars
with enhanced high-velocity mass loss near the polar regions.Comment: 22 pages, 14 figures, 2 tables; A&A in pres
- âŠ