5,141 research outputs found
An Upper Limit on the Mass of a Central Black Hole in the Large Magellanic Cloud from the Stellar Rotation Field
We constrain the possible presence of a central black hole (BH) in the center
of the Large Magellanic Cloud (LMC). This requires spectroscopic measurements
over an area of order a square degree, due to the poorly known position of the
kinematic center. Such measurements are now possible with the impressive field
of view of the Multi Unit Spectroscopic Explorer (MUSE) on the ESO Very Large
Telescope. We used the Calcium Triplet (~850nm) spectral lines in many
short-exposure MUSE pointings to create a two-dimensional integrated-light
line-of-sight velocity map from the ~ individual spectra, taking care to
identify and remove Galactic foreground populations. The data reveal a clear
velocity gradient at an unprecedented spatial resolution of 1 arcmin. We
fit kinematic models to arrive at a upper-mass-limit of
M for any central BH - consistent with the known scaling relations for
supermassive black holes and their host systems. This adds to the growing body
of knowledge on the presence of BHs in low-mass and dwarf galaxies, and their
scaling relations with host-galaxy properties, which can shed light on theories
of BH growth and host system interaction.Comment: 12 pages, 11 figures, 1 table, ApJ - in pres
The Adequacy of State Insurance Rate Regulation: The McCarran-Ferguson Act in Historical Perspective
Any substantial inquiry into the functioning of the insurance commissioner in American society poses the question, at the threshold of the inquiry, whether state regulatory power over the insurance business is likely to continue, or whether insurance will fall increasingly under the aegis of the federal government. This article seeks to ascertain the minimum conditions for the permanent preservation of state regulatory power over the insurance business, and to determine whether they are now satisfied. These conditions may be summarily stated: the Congress of the United States has shown its willingness to apply federal antitrust and marketing legislation to the insurance business, to the extent that the states do not regulate. Application of such statutes would have destructive impact on the present structure of the insurance business. Even more important, it seems possible that once the federal government entered the field of insurance regulation, the scope of its intervention might increase until it occupied the field. Though rate regulation has been one of the lesser functions of the state insurance commissioner, federal concern with combinations of insurers to fix premium rates has now made adequate state regulation of rate making pivotal for the preservation of state control over insurance. Unless the commissioner is able to perform his statutory duty of regulating rates well enough to prevent effective pressures for federal regulation, he may cease to have any role to play in our society
J0316+4328: a Probable "Asymmetric Double" Lens
We report a probable gravitational lens J0316+4328, one of 19 candidate
asymmetric double lenses (2 images at a high flux density ratio) from CLASS.
Observations with the Very Large Array (VLA), MERLIN and the Very Long Baseline
Array (VLBA) imply that J0316+4328 is a lens with high confidence. It has 2
images separated by 0.40", with 6 GHz flux densities of 62 mJy and 3.2 mJy. The
flux density ratio of ~19 (constant over the frequency range 6-22 GHz) is the
largest for any 2 image gravitational lens. High resolution optical imaging and
deeper VLBI maps should confirm the lensing interpretation and provide inputs
to detailed lens models. The unique configuration will give strong constraints
on the lens galaxy's mass profile.Comment: Accepted to MNRAS Letters. 5 pages, 6 figures, 3 table
Ignition enhancement via radical farming in two-dimensional supersonic combustion
A two-dimensional numerical study has been performed of the ignition processes associated with the concept of radical farming for supersonic combustion. In a preliminary parametric study, a range of freestream conditions attainable in a hypersonic shock tunnel has been investigated, and mapped according to whether or not the behaviour known as radical farming is present - combustion-induced pressure rise in second or subsequent hot pockets rather than the first. One such case has been analysed in detail, having mean conditions across the combustion chamber entrance that would result in extremely long ignition lengths. The branching cycle and heat release reactions in the combustion process become active in the radical farm, and H and OH radicals are produced. Their rate of production slows in the expansion, but does not approach chemical freezing until towards the end of it. When the mixture flows through the shock at the second hot pocket, the presence of radicals enables the branching cycle and three-body recombination heat release reactions to accelerate, and significant pressure rise due to heat release is then able to occur
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Supporting desistance through ambiguous practice: what can be learned from the first prison-based model of CoSA in England and Wales?
Circles of Support and Accountability (CoSA) are an initiative designed to support those previously convicted of sexual offences as they reintegrate back in to society, whilst still holding them accountable for their thoughts and behaviour (Cesaroni, 2002). The aim of the research was to explore the Core Member and volunteer experience of being involved in a CoSA that transitions from prison to community, with the objective being to focus upon what can be learnt from these initial experiences. The study included qualitative interviews with two separate groups of participants; Core Members (n=7) and volunteers (n=10) involved in the prison-model CoSA. Interpretative Phenomenological Analysis of the data was undertaken to consider the individual’s subjective experience of being involved in this initiative.
A superordinate theme of ambiguous practice was identified, whereby volunteers appeared to overlook the importance of expressive support, described a lack of commitment from other fellow volunteers and demonstrated a confusion surrounding the accountability aspect of their role. Despite the confusion highlighted, however, the accountability aspect of the volunteers’ role was identified through their indirect support of Core members’ desistance. The second superordinate theme outlined the volunteers’ encouragement of the Core Members new pro-social lifestyle, thus helping to reinforce their crime -free identity. This led to a concern, however, of what would happen once the CoSA journey had come to an end.
The learning derived from these findings can now be used to continue to develop and improve the use of prison-model CoSA across England and Wales
A survey of falls in people with dystonia.
ObjectiveDystonia is a chronic and sometimes progressive neurological disorder causing abnormalities in movement and function. We conducted a preliminary survey to investigate whether people with dystonia experience falls and to identify contributing factors to falls in this population.MethodsAn online survey of people with dystonia was conducted in November 2015. Respondents were asked to complete demographic information, three questionnaires (the Falls Self-Efficacy Scale International [FES-I], the Activities-based Balance Confidence Scale [ABC] and the Functional Disability Questionnaire [FDQ]), and to report any falls sustained during the previous 6 months.ResultsThirty-nine percent of the 122 respondents reported falling in the previous 6 months and 65% of fallers were diagnosed with dystonia not affecting the lower limbs. Fallers reported lower falls self-efficacy and balance confidence with higher functional disability. Both falling scales correlated with self-reported functional disability. Linear regression analysis for falls prediction revealed the variables FES-I and FDQ accounted for almost 30% of the falls in this dystonia population.ConclusionThis survey indicates that fear of falling and balance confidence are impaired in people with dystonia, possibly impacting on function and falls. Further investigation into balance, function and falls in this population is required
Hydrochemistry and stable isotopes as tools for understanding the sustainability of minewater geothermal energy production from a ‘standing column’ heat pump system : Markham Colliery, Bolsover, Derbyshire, UK
The abandoned workings of the former Markham Colliery are still in the process of flooding. They are being exploited, via a‘standing column’heat pump arrangement in Markham No. 3 shaft, to produce thermal energy.From 2012, water was pumped from 235 m below ground level in the shaft at c. 15 °C and 2–3 l/s, through shell and tube heat exchangers coupled to a 20 kW heat pump, to supply space heating to commercial offices.The thermally spent (cool) water was returned to the same shaft at c. 250 m bgl at around 12 °C. The minewater contained iron, c. 6000 mg/l chloride, and was highly reducing. Avoiding contact with oxygen was effective in preventing problems with ochre scaling. In January 2015, taking advantage of rising water levels, the pump was repositioned at 170 m bgl, and the reinjection diffuser at 153 m bgl. Since then, both iron concentration and salinity have fallen significantly, suggesting stratification in the shaft. Stable isotope data from sampling in 2015 generally show little variation. Sulphate δ34S exhibits values typical for British Coal Measures (c. +5‰),whilstδ18O/δ2H indicate influence of fresh meteoric waters. Chloride and sodium concentrations have gradually increased since May 2015, possibly indicating a renewed influence of deeper, more saline, waters and reflecting the gradual rise of mine water in the shaft. Further monitoring of mine water chemistry and isotopic compositionis required to better assess the sustainability of the Markham heat pump scheme and advise on optimal management of this mine water resource
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