22,694 research outputs found
Transport dynamics of ultracold atoms in a triple-well transistor-like potential
The transport of atoms is experimentally studied in a transistor-like
triple-well potential consisting of a narrow gate well surrounded by source and
drain wells. Atoms are initially loaded into the source well with
pre-determined temperature and chemical potential. Energetic atoms flow from
the source, across the gate, and into the drain where they are removed using a
resonant light beam. The manifestation of atom-atom interactions and
dissipation is evidenced by a rapid population growth in the initially vacant
gate well. The transport dynamics are shown to depend strongly on a feedback
parameter determined by the relative heights of the two barriers forming the
gate region. For a range of feedback parameter values, experiments establish
that the gate atoms develop a larger chemical potential and lower temperature
than those in the source.Comment: 13 pages, 5 figures, accepted for publication in NJ
Doppler-beaming in the Kepler light curve of LHS 6343 A
Context. Kepler observations revealed a brown dwarf eclipsing the M-type star
LHS 6343 A with a period of 12.71 days. In addition, an out-of-eclipse light
modulation with the same period and a relative semi-amplitude of 2 x 10^-4 was
observed showing an almost constant phase lag to the eclipses produced by the
brown dwarf. In a previous work, we concluded that this was due to the light
modulation induced by photospheric active regions in LHS 6343 A. Aims. In the
present work, we prove that most of the out-of-eclipse light modulation is
caused by the Doppler-beaming induced by the orbital motion of the primary
star. Methods. We introduce a model of the Doppler-beaming for an eccentric
orbit and also considered the ellipsoidal effect. The data were fitted using a
Bayesian approach implemented through a Monte Carlo Markov chain method. Model
residuals were analysed by searching for periodicities using a Lomb-Scargle
periodogram. Results. For the first seven quarters of Kepler observations and
the orbit previously derived from the radial velocity measurements, we show
that the light modulation of the system outside eclipses is dominated by the
Doppler-beaming effect. A period search performed on the residuals shows a
significant periodicity of 42.5 +- 3.2 days with a false-alarm probability of 5
x 10^-4, probably associated with the rotational modulation of the primary
component.Comment: 6 pages, 7 figure
Thanks, but no thanks: women's avoidance of help-seeking in the context of a dependency-related stereotype
The stereotype that women are dependent on men is a commonly verbalized, potentially damaging aspect of benevolent sexism. We investigated how women may use behavioral disconfirmation of the personal applicability of the stereotype to negotiate such sexism. In an experiment (N = 86), we manipulated female college studentsâ awareness that women may be stereotyped by men as dependent. We then placed participants in a situation where they needed help. Women made aware of the dependency stereotype (compared to controls who were not) were less willing to seek help. They also displayed a stronger negative correlation between help-seeking and post help-seeking affect - such that the more help they sought, the worse they felt. We discuss the relevance of these findings for research concerning womenâs help-seeking and their management of sexist stereotyping in everyday interaction. We also consider the implications of our results for those working in domains such as healthcare, teaching and counseling, where interaction with individuals in need and requiring help is common
Chapter 10 Telepractice in adult speech-language pathology during COVID-19
This collection is the first of its kind to examine the impact of the COVID-19 pandemic on the caseloads and clinical practice of speech-language pathologists. The volume synthesises existing data on the wide-ranging effects of COVID-19 on the communication, swallowing, and language skills of individuals with COVID infection. Featuring perspectives of scholars and practitioners from around the globe, the book examines the ways in which clinicians have had to modify their working practices to prioritise patient and clinician safety, including the significant increase in the use of telepractice during the pandemic. The volume also reflects on changes in training and education which have seen educators in the field redesign their clinical practicum in order to best prepare students for professional practice in an age of COVID-19 and beyond, as the field continues to grapple with the long-term effects of the pandemic. Offering a holistic treatment of the impact of COVID-19 on the work of speech-language pathologists, this book will be of interest to students, researchers, and clinicians working in the discipline
Estimating the masses of extra-solar planets
All extra-solar planet masses that have been derived spectroscopically are
lower limits since the inclination of the orbit to our line-of-sight is unknown
except for transiting systems. It is, however, possible to determine the
inclination angle, i, between the rotation axis of a star and an observer's
line-of-sight from measurements of the projected equatorial velocity (v sin i),
the stellar rotation period (P_rot) and the stellar radius (R_star). This
allows the removal of the sin i dependency of spectroscopically derived
extra-solar planet masses under the assumption that the planetary orbits lie
perpendicular to the stellar rotation axis. We have carried out an extensive
literature search and present a catalogue of v sin i, P_rot, and R_star
estimates for exoplanet host stars. In addition, we have used Hipparcos
parallaxes and the Barnes-Evans relationship to further supplement the R_star
estimates obtained from the literature. Using this catalogue, we have obtained
sin i estimates using a Markov-chain Monte Carlo analysis. This allows proper
1-sigma two-tailed confidence limits to be placed on the derived sin i's along
with the transit probability for each planet to be determined. While a small
proportion of systems yield sin i's significantly greater than 1, most likely
due to poor P_rot estimations, the large majority are acceptable. We are
further encouraged by the cases where we have data on transiting systems, as
the technique indicates inclinations of ~90 degrees and high transit
probabilities. In total, we estimate the true masses of 133 extra-solar
planets. Of these, only 6 have revised masses that place them above the 13
Jupiter mass deuterium burning limit. Our work reveals a population of
high-mass planets with low eccentricities and we speculate that these may
represent the signature of different planetary formation mechanisms at work.Comment: 40 pages, 6 tables, 2 figures. Accepted for publication in the
Monthly Notices of the Royal Astronomical Society after editing of Tables 1 &
6 for electronic publication. Html abstract shortened for astro-ph submissio
Cluster Cosmology Redux: A Compact Model of the Halo Mass Function
Massive halos hosting groups and clusters of galaxies imprint coherent,
arcminute-scale features across the spectrophotometric sky, especially
optical-IR clusters of galaxies, distortions in the sub-mm CMB, and extended
sources of X-ray emission. Statistical modeling of such features often rely
upon the evolving space-time density of dark matter halos -- the halo mass
function (HMF) -- as a common theoretical ground for cosmological,
astrophysical and fundamental physics studies. We propose a compact (eight
parameter) representation of the HMF with readily interpretable parameters that
stem from polynomial expansions, first in terms of log-mass, then expanding
those coefficients similarly in redshift. We demonstrate good ()
agreement of this form, referred to as the dual-quadratic (DQ-HMF), with
Mira-Titan N-body emulator estimates for halo masses above over the redshift range , present best-fit
parameters for a Planck 2018 cosmology, and present parameter variation in the
plane. Convolving with a minimal mass-observable
relation (MOR) yields closed-form expressions for counts, mean mass, and mass
variance of cluster samples characterized by some observable property.
Performing information-matrix forecasts of potential parameter constraints from
existing and future surveys under different levels of systematic uncertainties,
we demonstrate the potential for percent-level constraints on model parameters
by an LSST-like optical cluster survey of 300,000 clusters and a richness-mass
variance of . Even better constraints could potentially be achieved by a
survey with one-tenth the sample size but with a reduced selection property
variance of . Potential benefits and extensions to the basic MOR
parameterization are discussed.Comment: 18 pages, 9 figure
High magnetic field studies of the Vortex Lattice structure in YBa2Cu3O7
We report on small angle neutron scattering measurements of the vortex
lattice in twin-free YBa2Cu3O7, extending the previously investigated maximum
field of 11~T up to 16.7~T with the field applied parallel to the c axis. This
is the first microscopic study of vortex matter in this region of the
superconducting phase. We find the high field VL displays a rhombic structure,
with a field-dependent coordination that passes through a square configuration,
and which does not lock-in to a field-independent structure. The VL pinning
reduces with increasing temperature, but is seen to affect the VL correlation
length even above the irreversibility temperature of the lattice structure. At
high field and temperature we observe a melting transition, which appears to be
first order, with no detectable signal from a vortex liquid above the
transition
Promoting the achievement of looked after children and young people in South Tyneside
As of March 2016, there were 70,440 children and young people in care in England. The number of looked after children has continued to increase steadily over the last eight years. Sixty per cent of these children are in care because of abuse or neglect and three-quarters are placed in foster care arrangements. Children and young people who are in or have experienced care remain one of the lowest performing groups in terms of educational outcomes. Last year, 14% of looked after children achieved five or more A*âC GCSEs or equivalent, including English and mathematics. As a consequence, they also experience poorer employment and health outcomes after leaving school compared to their peers. They are over-represented amongst the offender population and those who experience homelessness. However, research is emerging to show that children and young people in care can have very positive experiences of school and are supported effectively to reach their full potential academically and socially. The purpose of this report is to share practice in selected South Tyneside schools that is contributing to improved outcomes and school experiences for children and young people in care. In July 2015, the South Tyneside Virtual School (VS) collaborated with UCL Institute of Education to run their Promoting the Achievement of Looked After Children (PALAC) programme with seven schools in the local authority (LA). This report presents an account of the programme, including the activities undertaken by the participants and the outcomes of the programme to date for students in care and staff in the participating school
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