250 research outputs found
Upper critical field in {BaKBiO}: magnetotransport versus magnetotunneling
Elastic tunneling is used as a powerful direct tool to determine the upper
critical field in the high- oxide BaKBiO. The
temperature dependence of inferred from the tunneling follows the
Werthamer-Helfand-Hohenberg prediction for type-II superconductors. A
comparison will be made with resistively determined critical field data.Comment: 4 pages incl. 5 figure
Life in 90 words: opportunities for person-centred care amidst COVID-19
Objective:
Coronavirus disease 2019 and the consequent public health and social distancing measures significantly impacted on service continuity for mental health patients. This article reports on contingency planning initiative in the Australian public sector.
Methods:
Ninety-word care synopses were developed for each patient. These formed the basis for guided conversations between case managers and consultant psychiatrists to ensure safe service provision and retain a person-centred focus amidst the threat of major staffing shortfalls.
Results:
This process identified vulnerable patient groups with specific communication needs and those most at risk through service contraction. The challenges and opportunities for promoting safety and self-management through proactive telehealth came up repeatedly. The guided conversations also raised awareness of the shared experience between patients and professionals of coronavirus disease 2019.
Conclusion:
There is a parallel pandemic of anxiety which creates a unique opportunity to connect at a human level
PROTECT: Relational Safety based Suicide Prevention Training Frameworks
Preventing suicide is a global priority and staff training is a core prevention strategy. However frontline pressures make translating training into better care and better outcomes difficult. The aim of the paper is to highlight challenges in suicide risk assessment and management and introduce training frameworks to assist with mindful practice so professionals can strike a balance between risk and recovery. We combined the scientific literature with contemporary practice from two successful initiatives from Cambridgeshire, UK; 333 – a recovery oriented model of inpatient/community crisis care and PROMISE – a programme to reduce coercion in care by enhancing patient experience. The resulting PROTECT (PROactive deTECTion) frameworks operationalise ongoing practice of relational safety in these programmes. PROTECT is a combination of novel concepts and adaptations of well-established therapeutic approaches. It has four training frameworks: AWARE for reflection on clinical decisions; DESPAIR for assessment; ASPIRE for management; NOTES
for documentation. PROTECT aims to improve self-awareness of mental shortcuts, risk taking thresholds and increase rigour through time efficient crosschecks. The training frameworks should support a relational approach to self-harm/suicide risk detection, mitigation and documentation, making care safer and person-centred. The goal is to enthuse practitioners with recovery oriented practice that draws on the strengths of the person in distress and their natural circle of support. It will provide the confidence to engage in participatory approaches to seek out unique individualised solutions to the overwhelming psychological pain of suicidal distress. Future collaborative research with people with lived and carer experience is needed for fine-tuning
The Star Formation History of NGC 6822
Images of five fields in the Local Group dwarf irregular galaxy NGC 6822
obtained with the {\it Hubble Space Telescope} in the F555W and F814W filters
are presented. Photometry for the stars in these images was extracted using the
Point-Spread-Function fitting program HSTPHOT/MULTIPHOT. The resulting
color-magnitude diagrams reach down to , a level well below the red
clump, and were used to solve quantitatively for the star formation history of
NGC 6822. Assuming that stars began forming in this galaxy from low-metallicity
gas and that there is little variation in the metallicity at each age, the
distribution of stars along the red giant branch is best fit with star
formation beginning in NGC 6822 12-15 Gyr ago. The best-fitting star formation
histories for the old and intermediate age stars are similar among the five
fields and show a constant or somewhat increasing star formation rate from 15
Gyr ago to the present except for a possible dip in the star formation rate
from 3 to 5 Gyr ago. The main differences among the five fields are in the
higher overall star formation rate per area in the bar fields as well as in the
ratio of the recent star formation rate to the average past rate. These
variations in the recent star formation rate imply that stars formed within the
past 0.6 Gyr are not spatially very well mixed throughout the galaxy.Comment: 47 pages, 28 Figures, accepted for publication in the Astronomical
Journa
Large-Amplitude Ultraviolet Variations in the RR Lyrae Star ROTSE-I J143753.84+345924.8
The NASA Galaxy Evolution Explorer (GALEX) satellite has obtained
simultaneous near and far ultraviolet light curves of the ROTSE-I Catalog RR
Lyrae ab-type variable star J143753.84+345924.8. A series of 38 GALEX Deep
Imaging Survey observations well distributed in phase within the star's
0.56432d period shows an AB=4.9mag variation in the far UV (1350-1750A) band
and an AB=1.8mag variation in the near UV (1750-2750A) band, compared with only
a 0.8mag variation in the broad, unfiltered ROTSE-I (4500-10000A) band. These
GALEX UV observations are the first to reveal a large RR Lyrae amplitude
variation at wavelengths below 1800A. We compare the GALEX and ROTSE-I
observations to predictions made by recent Kurucz stellar atmosphere models. We
use published physical parameters for the comparable period (0.57433d),
well-observed RR Lyrae star WY Antliae to compute predicted FUV, NUV, and
ROTSE-I light curves for J143753.84+345924.8. The observed light curves agree
with the Kurucz predictions for [Fe/H]=-1.25 to within AB=0.2mag in the GALEX
NUV and ROTSE-I bands, and within 0.5mag in the FUV. At all metallicities
between solar and one hundredth solar, the Kurucz models predict 6-8mag of
variation at wavelengths between 1000-1700A. Other variable stars with similar
temperature variations, such as Cepheids, should also have large-amplitude FUV
light curves, observable during the ongoing GALEX imaging surveys.Comment: This paper will be published as part of the Galaxy Evolution Explorer
(GALEX) Astrophysical Journal Letters Special Issue. Links to the full set of
papers will be available at http:/www.galex.caltech.edu/PUBLICATIONS after
November 22, 200
The Local Universe as Seen in Far-Infrared and in Far-Ultraviolet: A Global Point of View on the Local Recent Star Formation
We select far-infrared (FIR-60 microns) and far-ultraviolet (FUV-1530 A)
samples of nearby galaxies in order to discuss the biases encountered by
monochromatic surveys (FIR or FUV). Very different volumes are sampled by each
selection and much care is taken to apply volume corrections to all the
analyses. The distributions of the bolometric luminosity of young stars are
compared for both samples: they are found to be consistent with each other for
galaxies of intermediate luminosities but some differences are found for high
(>5 10^{10} L_sun) luminosities. The shallowness of the IRAS survey prevents us
from securing comparison at low luminosities (<2 10^9 L_sun). The ratio of the
total infrared (TIR) luminosity to the FUV luminosity is found to increase with
the bolometric luminosity in a similar way for both samples up to 5 10^{10}
L_sun. Brighter galaxies are found to have a different behavior according to
their selection: the L_TIR/L_FUV ratio of the FUV-selected galaxies brighter
than 5 10^{10} L_sun reaches a plateau whereas L_TIR/L_FUV continues to
increase with the luminosity of bright galaxies selected in FIR. The
volume-averaged specific star formation rate (SFR per unit galaxy stellar mass,
SSFR) is found to decrease toward massive galaxies within each selection. The
SSFR is found to be larger than that measured for optical and NIR-selected
sample over the whole mass range for the FIR selection, and for masses larger
than 10^{10} M_sun for the FUV selection. Luminous and massive galaxies
selected in FIR appear as active as galaxies with similar characteristics
detected at z ~ 0.7.Comment: 32 pages, 9 figures, to be published in the Astrophysical Journal
Supplement series dedicated to GALEX result
Magnetic state in URu2Si2, UPd2Al3 and UNi2Al3 probed by point contacts
The antiferromagnetic (AFM) state has been investigated in the three
heavy-fermion compounds URu2Si2, UPd2Al3, and UNi2Al3 by measuring dV/dI(V)
curves of point contacts at different temperatures (1.5-20 K) and magnetic
fields (0-28 T). The zero-bias maximum in dV/dI(V) for URu2Si2 points to a
partially gapped Fermi-surface related to the itinerant nature of the AFM state
contrary to UPd2Al3 where analogous features have not been found. The AFM state
in UNi2Al3 has more similarities with URu2Si2. For URu2Si2, the same critical
field of about 40 T along the easy c axis is found for all features in dV/dI(V)
corresponding to the Neel temperature, the gap in the electronic density of
states, and presumably the ordered moments.Comment: 10 pages incl. 5 figures, LaTex 2
The effect of environment on the UV colour-magnitude relation of early-type galaxies
We use \textit{GALEX} (Galaxy Evolution Explorer) near-UV (NUV) photometry of
a sample of early-type galaxies selected in \textit{SDSS} (Sloan Digital Sky
Survey) to study the UV color-magnitude relation (CMR). color is an
excellent tracer of even small amounts (% mass fraction) of recent
(\la 1 Gyr) star formation and so the CMR allows us to study the
effect of environment on the recent star formation history. We analyze a
volume-limited sample of 839 visually-inspected early-type galaxies in the
redshift range brighter than of -21.5 with any
possible emission-line or radio-selected AGN removed to avoid contamination. We
find that contamination by AGN candidates and late-type interlopers highly bias
any study of recent star formation in early-type galaxies and that, after
removing those, our lower limit to the fraction of massive early-type galaxies
showing signs of recent star formation is roughly This suggests
that residual star formation is common even amongst the present day early-type
galaxy population.
We find that the fraction of UV-bright early-type galaxies is 25% higher in
low-density environments. However, the density effect is clear only in the
lowest density bin. The blue galaxy fraction for the subsample of the brightest
early-type galaxies however shows a very strong density dependence, in the
sense that the blue galaxy fraction is lower in a higher density region.Comment: Accepted for publication in ApJ, paper with high-resolution figures
can be downloaded at:
http://www-astro.physics.ox.ac.uk/~kevins/PAPERS/uv_environment.p
Coherence in the Quasi-Particle 'Scattering' by the Vortex Lattice in Pure Type-II Superconductors
The effect of quasi-particle (QP) 'scattering' by the vortex lattice on the
de-Haas van-Alphen oscillations in a pure type-II superconductor is
investigated within mean field,asymptotic perturbation theory. Using a 2D
electron gas model it is shown that, due to a strict phase coherence in the
many-particle correlation functions, the 'scattering' effect in the asymptotic
limit () is much weaker than what is predicted
by the random vortex lattice model proposed by Maki and Stephen, which destroys
this coherence . The coherent many particle configuration is a collinear array
of many particle coordinates, localized within a spatial region with size of
the order of the magnetic length. The amplitude of the magnetization
oscillations is sharply damped just below because of strong
out of phase magnetic oscillations in the superconducting
condensation energy ,which tend to cancel the normal electron oscillations.
Within the ideal 2D model used it is found, however, that because of the
relative smallness of the quartic and higher order terms in the expansion, the
oscillations amplitude at lower fields does not really damp to zero, but only
reverses sign and remains virtually undamped well below . This
conclusion may be changed if disorder in the vortex lattice, or vortex lines
motion will be taken into account. The reduced QP 'scattering' effect may be
responsible for the apparent crossover from a strong damping of the dHvA
oscillations just below to a weaker damping at lower fields observed
experimentally in several 3D superconductors.Comment: 26 pages, Revtex no Figure
The GALEX UV luminosity function of the cluster of galaxies Abell 1367
We present the GALEX NUV (2310 A) and FUV (1530 A) galaxy luminosity
functions of the nearby cluster of galaxies A1367 in the magnitude range -20.3<
M_AB < -13.3. The luminosity functions are consistent with previous (~ 2 mag
shallower) estimates based on the FOCA and FAUST experiments, but display a
steeper faint-end slope than the GALEX luminosity function for local field
galaxies. Using spectro-photometric optical data we select out star-forming
systems from quiescent galaxies and study their separate contributions to the
cluster luminosity function. We find that the UV luminosity function of cluster
star-forming galaxies is consistent with the field. The difference between the
cluster and field LF is entirely due to the contribution at low luminosities
(M_AB >-16 mag) of non star-forming, early-type galaxies that are significantly
over dense in clusters.Comment: 4 pages, 4 figures, 1 table. Accepted for publication in
Astrophysical Journal Letter
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