2,859 research outputs found
Women\u27s Wage Gap Around the World
We compared the gender gap between the regions of North America, Europe, Latin American and the Caribbean, East Asia and the Pacific, Sub-Saharan Africa, Middle East and North Africa and lastly South Asia.https://digitalcommons.butler.edu/spring_2023/1010/thumbnail.jp
Damage-free single-mode transmission of deep-UV light in hollow-core PCF
Transmission of UV light with high beam quality and pointing stability is
desirable for many experiments in atomic, molecular and optical physics. In
particular, laser cooling and coherent manipulation of trapped ions with
transitions in the UV require stable, single-mode light delivery. Transmitting
even ~2 mW CW light at 280 nm through silica solid-core fibers has previously
been found to cause transmission degradation after just a few hours due to
optical damage. We show that photonic crystal fiber of the kagom\'e type can be
used for effectively single-mode transmission with acceptable loss and bending
sensitivity. No transmission degradation was observed even after >100 hours of
operation with 15 mW CW input power. In addition it is shown that
implementation of the fiber in a trapped ion experiment significantly increases
the coherence times of the internal state transfer due to an increase in beam
pointing stability
WR 110: A Single Wolf-Rayet Star With Corotating Interaction Regions In Its Wind?
A 30-day contiguous photometric run with the MOST satellite on the WN5-6b
star WR 110 (HD 165688) reveals a fundamental periodicity of P = 4.08 +/- 0.55
days along with a number of harmonics at periods P/n, with n ~ 2,3,4,5 and 6,
and a few other possible stray periodicities and/or stochastic variability on
timescales longer than about a day. Spectroscopic RV studies fail to reveal any
plausible companion with a period in this range. Therefore, we conjecture that
the observed light-curve cusps of amplitude ~ 0.01 mag that recur at a 4.08 day
timescale may arise in the inner parts, or at the base of, a corotating
interaction region (CIR) seen in emission as it rotates around with the star at
constant angular velocity. The hard X-ray component seen in WR 110 could then
be a result of a high velocity component of the CIR shock interacting with the
ambient wind at several stellar radii. Given that most hot, luminous stars
showing CIRs have two CIR arms, it is possible that either the fundamental
period is 8.2 days or, more likely in the case of WR 110, there is indeed a
second weaker CIR arm for P = 4.08 days, that occurs ~ two thirds of a rotation
period after the main CIR. If this interpretation is correct, WR 110 therefore
joins the ranks with three other single WR stars, all WN, with confirmed CIR
rotation periods (WR 1, WR 6, and WR 134), albeit with WR 110 having by far the
lowest amplitude photometric modulation. This illustrates the power of being
able to secure intense, continuous high-precision photometry from space-based
platforms such as MOST. It also opens the door to revealing low-amplitude
photometric variations in other WN stars, where previous attempts have failed.
If all WN stars have CIRs at some level, this could be important for revealing
sources of magnetism or pulsation in addition to rotation periods.Comment: 25 pages, 8 figures, 2 tables, accepted in Ap
Anisotropic turbulence in weakly stratified rotating magnetoconvection
Numerical simulations of the 3D MHD-equations that describe rotating
magnetoconvection in a Cartesian box have been performed using the code
NIRVANA. The characteristics of averaged quantities like the turbulence
intensity and the turbulent heat flux that are caused by the combined action of
the small-scale fluctuations are computed. The correlation length of the
turbulence significantly depends on the strength and orientation of the
magnetic field and the anisotropic behavior of the turbulence intensity induced
by Coriolis and Lorentz force is considerably more pronounced for faster
rotation. The development of isotropic behavior on the small scales -- as it is
observed in pure rotating convection -- vanishes even for a weak magnetic field
which results in a turbulent flow that is dominated by the vertical component.
In the presence of a horizontal magnetic field the vertical turbulent heat flux
slightly increases with increasing field strength, so that cooling of the
rotating system is facilitated. Horizontal transport of heat is always directed
westwards and towards the poles. The latter might be a source of a large-scale
meridional flow whereas the first would be important in global simulations in
case of non-axisymmetric boundary conditions for the heat flux.Comment: 13 pages 11 figure
Massive pulsating stars observed by BRITE-Constellation. I. The triple system Beta Centauri (Agena)
This paper aims to precisely determine the masses and detect pulsation modes
in the two massive components of Beta Cen with BRITE-Constellation photometry.
In addition, seismic models for the components are considered and the effects
of fast rotation are discussed. This is done to test the limitations of seismic
modeling for this very difficult case. A simultaneous fit of visual and
spectroscopic orbits is used to self-consistently derive the orbital
parameters, and subsequently the masses, of the components. The derived masses
are equal to 12.02 +/- 0.13 and 10.58 +/- 0.18 M_Sun. The parameters of the
wider, A - B system, presently approaching periastron passage, are constrained.
Analysis of the combined blue- and red-filter BRITE-Constellation photometric
data of the system revealed the presence of 19 periodic terms, of which eight
are likely g modes, nine are p modes, and the remaining two are combination
terms. It cannot be excluded that one or two low-frequency terms are rotational
frequencies. It is possible that both components of Beta Cen are Beta Cep/SPB
hybrids. An attempt to use the apparent changes of frequency to distinguish
which modes originate in which component did not succeed, but there is
potential for using this method when more BRITE data become available. Agena
seems to be one of very few rapidly rotating massive objects with rich p- and
g-mode spectra, and precisely known masses. It can therefore be used to gain a
better understanding of the excitation of pulsations in relatively rapidly
rotating stars and their seismic modeling. Finally, this case illustrates the
potential of BRITE-Constellation data for the detection of rich-frequency
spectra of small-amplitude modes in massive pulsating stars.Comment: 17 pages (with Appendix), 15 figures, accepted for publication in A&
Investigating the association between obesity and asthma in 6- to 8-year-old Saudi children:a matched case-control study
Background: Previous studies have demonstrated an association between obesity and asthma, but there remains considerable uncertainty about whether this reflects an underlying causal relationship. Aims: To investigate the association between obesity and asthma in pre-pubertal children and to investigate the roles of airway obstruction and atopy as possible causal mechanisms. Methods: We conducted an age- and sex-matched case–control study of 1,264 6- to 8-year-old schoolchildren with and without asthma recruited from 37 randomly selected schools in Madinah, Saudi Arabia. The body mass index (BMI), waist circumference and skin fold thickness of the 632 children with asthma were compared with those of the 632 control children without asthma. Associations between obesity and asthma, adjusted for other potential risk factors, were assessed separately in boys and girls using conditional logistic regression analysis. The possible mediating roles of atopy and airway obstruction were studied by investigating the impact of incorporating data on sensitisation to common aeroallergens and measurements of lung function. Results: BMI was associated with asthma in boys (odds ratio (OR)=1.14, 95% confidence interval (CI), 1.08–1.20; adjusted OR=1.11, 95% CI, 1.03–1.19) and girls (OR=1.37, 95% CI, 1.26–1.50; adjusted OR=1.38, 95% CI, 1.23–1.56). Adjusting for forced expiratory volume in 1 s had a negligible impact on these associations, but these were attenuated following adjustment for allergic sensitisation, particularly in girls (girls: OR=1.25; 95% CI, 0.96–1.60; boys: OR=1.09, 95% CI, 0.99–1.19). Conclusions: BMI is associated with asthma in pre-pubertal Saudi boys and girls; this effect does not appear to be mediated through respiratory obstruction, but in girls this may at least partially be mediated through increased risk of allergic sensitisation
Health literacy, health status, and healthcare utilization of Taiwanese adults: results from a national survey
Abstract Background Low health literacy is considered a worldwide health threat. The purpose of this study is to assess the prevalence and socio-demographic covariates of low health literacy in Taiwanese adults and to investigate the relationships between health literacy and health status and health care utilization. Methods A national survey of 1493 adults was conducted in 2008. Health literacy was measured using the Mandarin Health Literacy Scale. Health status was measured based on self-rated physical and mental health. Health care utilization was measured based on self-reported outpatient clinic visits, emergency room visits, and hospitalizations. Results Approximately thirty percent of adults were found to have low (inadequate or marginal) health literacy. They tended to be older, have fewer years of schooling, lower household income, and reside in less populated areas. Inadequate health literacy was associated with poorer mental health (OR, 0.57; 95% CI, 0.35-0.91). No association was found between health literacy and health care utilization even after adjusting for other covariates. Conclusions Low (inadequate and marginal) health literacy is prevalent in Taiwan. High prevalence of low health literacy is not necessarily indicative of the need for interventions. Systematic efforts to evaluate the impact of low health literacy on health outcomes in other countries would help to illuminate features of health care delivery and financing systems that may mitigate the adverse health effects of low health literacy.http://deepblue.lib.umich.edu/bitstream/2027.42/78252/1/1471-2458-10-614.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78252/2/1471-2458-10-614.pdfPeer Reviewe
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