2,210 research outputs found
Sanctions, support & service leavers : social security benefits and transitions from military to civilian life
Research report presenting findings from the first UK research focusing on the experiences of veterans in the social security system
Doppler tomography of the transient X-ray binary Centaurus X-4 in quiescence
We present ESO-NTT low resolution spectroscopy of the neutron star X-ray
transient Cen X-4 in quiescence over a complete orbital cycle. Our data reveal
the presence of a K3-7 V companion which contributes 63% to the 5600-6900A flux
and orbits the neutron star with a velocity semi-amplitude of K_2=145.8 +/- 1.0
km s^{-1}. This, combined with a previous determination of the inclination
angle and mass ratio, yields a neutron star and companion mass of M_1=1.5 +/-
1.0 M_Sun and M_2=0.31 +/- 0.27 M_Sun, respectively. The mass donor is thus
undermassive for the inferred spectral type indicating it is probably evolved,
in agreement with previous studies. Doppler tomography of the H_alpha line
shows prominent emission located on the companion and a slightly asymmetric
accretion disc distribution similar to that seen in systems with precessing
eccentric discs. Strong H_alpha emission from the companion can be explained by
X-ray irradiation from the primary. No evidence is found for a hot spot in
H_alpha, whereas one is revealed via Doppler tomography of the HeI lines. This
can be interpreted as the hot spot and outer regions of the disc being at a
higher temperature than in other systems.Comment: 9 pages, 5 figures, accepted for publication in A&
Remote Sensing Of Asteroid Surface Mineralogy
A major research question in asteroid science centres on how fragments from main belt asteroids, which are located between the orbits of Mars and Jupiter, end up in Earth crossing orbits. Advances in infrared astronomy have made it possible to test the validity of solar system dynamical models using observational data. Specifically, near-infrared (NIR) reflectance spectroscopy can be employed to search the main asteroid belt for possible mineralogical analogues of Near Earth asteroids. Two asteroids, 3628 Božněmcová and 2002 JB9, were studied using the NASA Infrared Telescope Facility. 3628 Božněmcová had been suggested as a possible parent body for ordinary chondrite meteorites due to its unique spectral characteristics and the fact that it orbits in the vicinity of the 3:1 Kirkwood gap. A more recent suggestion by Cloutis et al. (2006) is that 3628 Božněmcová is a type A clinopyroxene and possible parent body for the angrite meteorites.
The spectrum of 3628 Božněmcová obtained during the observing run of June 2011 shows distinct absorption features at 1.02 and 2.16 microns. It is therefore possible to effectively rule out an ordinary chrondrite or howardite-eucrite-diogenite (HED) mineralogy for this asteroid. While not entirely conclusive, the implied mineralogy for 3628 Božněmcová, i.e., a high calcium type B clinopyroxene with a possible fassite component, suggests it may be a possible parent body for the angrite meteorites
V344 Lyrae: A Touchstone SU UMa Cataclysmic Variable in the Kepler Field
We report on the analysis of the Kepler short-cadence (SC) light curve of
V344 Lyr obtained during 2009 June 20 through 2010 Mar 19 (Q2--Q4). The system
is an SU UMa star showing dwarf nova outbursts and superoutbursts, and promises
to be a touchstone for CV studies for the foreseeable future. The system
displays both positive and negative superhumps with periods of 2.20 and
2.06-hr, respectively, and we identify an orbital period of 2.11-hr. The
positive superhumps have a maximum amplitude of ~0.25-mag, the negative
superhumps a maximum amplitude of ~0.8 mag, and the orbital period at
quiescence has an amplitude of ~0.025 mag. The quality of the Kepler data is
such that we can test vigorously the models for accretion disk dynamics that
have been emerging in the past several years. The SC data for V344 Lyr are
consistent with the model that two physical sources yield positive superhumps:
early in the superoutburst, the superhump signal is generated by viscous
dissipation within the periodically flexing disk, but late in the
superoutburst, the signal is generated as the accretion stream bright spot
sweeps around the rim of the non-axisymmetric disk. The disk superhumps are
roughly anti-phased with the stream/late superhumps. The V344 Lyr data also
reveal negative superhumps arising from accretion onto a tilted disk precessing
in the retrograde direction, and suggest that negative superhumps may appear
during the decline of DN outbursts. The period of negative superhumps has a
positive dP/dt in between outbursts.Comment: ApJ, In Press (20 pages, 27 figures) A version with full-resolution
figures is available at http://www.astro.fit.edu/wood/WoodV344.pd
Black hole accretion disks in the canonical low-hard state
Stellar-mass black holes in the low-hard state may hold clues to jet
formation and basic accretion disk physics, but the nature of the accretion
flow remains uncertain. A standard thin disk can extend close to the innermost
stable circular orbit, but the inner disk may evaporate when the mass accretion
rate is reduced. Blackbody-like continuum emission and dynamically-broadened
iron emission lines provide independent means of probing the radial extent of
the inner disk. Here, we present an X-ray study of eight black holes in the
low-hard state. A thermal disk continuum with a colour temperature consistent
with is clearly detected in all eight sources, down to
. In six sources, disk models exclude a
truncation radius larger than 10rg. Iron-ka fluorescence line emission is
observed in half of the sample, down to luminosities of
. Detailed fits to the line profiles exclude a
truncated disk in each case. If strong evidence of truncation is defined as (1)
a non-detection of a broad iron line, {\it and} (2) an inner disk temperature
much cooler than expected from the relation, none
of the spectra in this sample offer strong evidence of disk truncation. This
suggests that the inner disk may evaporate at or below
.Comment: Accepted for publication in MNRAS, 20 pages, 18 figure
What is the closest black hole to the Sun?
We examine the distance of the two galactic microquasars GRO J1655-40 and
A0620-00, which are potentially the two closest black holes to the Sun. We aim
to provide a picture as wide and complete as possible of the problem of
measuring the distance of microquasars in our Galaxy. The purpose of this work
is to fairly and critically review in great detail every distance method used
for these two microquasars in order to show that the distances of probably all
microquasars in our galaxy are much more uncertain than currently admitted.
Moreover, we show that many confirmations of quantitative results are often
entangled and rely on very uncertain measurements. We also present a new
determination of the maximum distance of GRO J1655-40 using red clump giant
stars, and show that it confirms our earlier result of a distance less than 2
kpc instead of 3.2 kpc. Since it then becomes more likely that GRO J1655-40
could originate from the stellar cluster NGC 6242, located at 1.0 kpc, we
review the distance estimations of A0620-00, which is so far the closest black
hole with an average distance of about 1.0 kpc. We show that the distance
methods used for A0620-00 are also problematic. Finally, we present a new
analysis of spectroscopic and astrometric archival data on this microquasar,
and apply the maximum-distance method of Foellmi et al. (2006). It appears that
A0620-00 could indeed be even closer to the Sun than currently estimated, and
consequently would be the closest known black hole to the Sun.Comment: Accepted for publication in New Astronomy. 27 pages, 7 figures, Added
new column in Table 1. Corrected definition of mass ratio in Equ 1
You’ll never walk alone: supportive social relations in a football and mental health project
Football can bring people together in acts of solidarity and togetherness. This spirit is most evocatively illustrated in the world renowned football anthem You’ll Never Walk Alone (YNWA). In this paper we argue that this spirit can be effectively harnessed in nursing and mental health care. We draw on data from qualitative interviews undertaken as part of evaluating a football and mental health project to explore the nature of supportive social relations therein. We use some of the lyrics from YNWA as metaphor to frame our thematic analysis. We are especially interested in the interactions between the group facilitators and group members, but also address aspects of peer support within the groups. A contrast is drawn between the flexible interpersonal boundaries and self-disclosure evident in the football initiative and the reported more distant relations with practitioners in mainstream mental health services. Findings suggest scope for utilising more collective, solidarity enhancing initiatives and attention to alliances and boundaries to maximise engagement and therapeutic benefits within routine practice
Food from the Oceans - How can more food and biomass be obtained from the oceans in a way that does not deprive future generations of their benefits?
Food from the Oceans is the first Evidence Review Report published by the SAPEA consortium. SAPEA is an integral part of the European Scientific Advice Mechanism (SAM) and this report demonstrates the outstanding commitment and knowledge of experts who were nominated by academies and learned societies.
Interdisciplinarity and world-class expertise from across Europe are SAPEA’s core strengths. We assembled two international working groups for Food from the Oceans, covering both the natural sciences and the humanities/social sciences.
We were delighted with SAPEA’s collaboration with the High-Level Group of Scientific Advisers (HLG), which has proved so effective in Food from the Oceans. Our Evidence Review Report informs the Scientific Opinion of the HLG. They are published together, and the aim is for them to be used by the European Commission in planning and policymaking across a range of areas.
Academia Europaea performed the role of Lead Academy for the Food from the Oceans Evidence Review Report. It acted as project manager, ensuring that deadlines were met, and outputs were of the highest quality standard. By working well with academies and experts we have met all milestones leading up to and including the final deliverable, the Evidence Review Report itself. We also took a novel approach to public engagement, with encouraging results.
In Food from the Oceans, we believe we have established an attractive model for future SAPEA projects. We would like to thank everyone involved in making Food from the Oceans a success and express our sincere gratitude to those who have worked hard throughout 2017
Harmful Algal Bloom Bulletins
Use Case Title: Harmful Algal Blooms
Environmental matrix of interest (Air, Ice, Mar. Water, etc.): Marine
Study Regions: Shelf Seas in Norway, Ireland and Spain
Dissemination Method: Web
Providing near real-time and forecast information for the aquaculture industry along Europe’s Atlantic coast is of vital importance in mitigating the effects of HABs. In this task, In-situ and satellite data will be amalgamated in a decision support system. In-situ data include oceanographic data e.g. water column structure, current speeds, biological samples (e.g. algal toxins, phytoplankton cell counts, barcoding) and hydrographic and biogeochemical information where possible. The In-situ data will be used to inform and validate biophysical models and to produce circulation forecasts for the coming three to five days. These data will undergo expert interpretation to produce an early warning bulletin to the aquaculture industry in Spain, Norway and Ireland. The bulletin will be distributed over a specified production season to fish farmers and shellfish production facilities so that husbandry and harvesting techniques can reflect the prevailing HAB conditions at any point in time
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