9,768 research outputs found
Cut loci and conjugate loci on Liouville surfaces
In the earlier paper (Itoh and Kiyohara, Manuscr Math 114:247–264, 2004), we showed that the cut locus of a general point on two-dimensional ellipsoid is a segment of a curvature line and proved "Jacobi’s last geometric statement" on the singularities of the conjugate locus. In the present paper,we showthat a wider class of Liouville surfaces possess such simple cut loci and conjugate loci. The results include the determination of cut loci and the set of poles on two-sheeted hyperboloids and elliptic paraboloids
Simulations of a Scintillator Compton Gamma Imager for Safety and Security
We are designing an all-scintillator Compton gamma imager for use in security
investigations and remediation actions involving radioactive threat material.
To satisfy requirements for a rugged and portable instrument, we have chosen
solid scintillator for the active volumes of both the scatter and absorber
detectors. Using the BEAMnrc/EGSnrc Monte Carlo simulation package, we have
constructed models using four different materials for the scatter detector:
LaBr_3, NaI, CaF_2 and PVT. We have compared the detector performances using
angular resolution, efficiency, and image resolution. We find that while PVT
provides worse performance than that of the detectors based entirely on
inorganic scintillators, all of the materials investigated for the scatter
detector have the potential to provide performance adequate for our purposes.Comment: Revised text and figures, Presented at SORMA West 2008, Published in
IEEE Transactions on Nuclear Scienc
Hypertensive encephalopathy with CT confirmation in four children with acute renal disease
Hypertensive encephalopathy (HE) is a clinical syndrome that occurs infrequently in children and is often underdiagnosed. We review four patients with HE and describe their clinical presentation and radiological findings on computed tomography (CT). Our cases demonstrate typical features on CT and correlate clinically with the syndrome of HE. Prompt recognition of the syndrome aids in earlier diagnosis and treatment, and hence proves beneficial to the patient
THE EFFECT OF RESISTED AND ASSISTED FREESTYLE SWIMMING ON STROKE MECHANICS
A three-dimensional analysis was conducted on the stroke mechanics of four female junior elite swimmers. They swam one 50 m freestyle trial for each of three conditions: resisted, assisted, and free swimming. Stroke length (SL), stroke rate (SR), maximum hand depth (rnax hand depth), body roll, and average forward velocity (avg fwd v) were evaluated. There was a significant difference (p < 0.05) found between conditions among SL. SR, rnax hand depth, and avg fwd v. During the resist trial, SL, SR, max hand depth, and avg fwd v all decreased. During the assist trial, SL, SR, avg fwd v increased, and rnax hand depth decreased. The changes due to resisted swimming suggest an undesirable affect on stroke mechanics. While some changes seen in assisted swimming may appear beneficial, both methods of tethered training remain questionable
The Partition Function of Multicomponent Log-Gases
We give an expression for the partition function of a one-dimensional log-gas
comprised of particles of (possibly) different integer charge at inverse
temperature {\beta} = 1 (restricted to the line in the presence of a
neutralizing field) in terms of the Berezin integral of an associated non-
homogeneous alternating tensor. This is the analog of the de Bruijn integral
identities [3] (for {\beta} = 1 and {\beta} = 4) ensembles extended to
multicomponent ensembles.Comment: 14 page
A Search for 6.7 GHz Methanol Masers in M33
We report the negative results from a search for 6.7 GHz methanol masers in
the nearby spiral galaxy M33. We observed 14 GMCs in the central 4 kpc of the
Galaxy, and found 3 sigma upper limits to the flux density of ~9 mJy in
spectral channels having a velocity width of 0.069 km/s. By velocity shifting
and combining the spectra from the positions observed, we obtain an effective
3sigma upper limit on the average emission of ~1mJy in a 0.25 km/s channel.
These limits lie significantly below what we would expect based on our
estimates of the methanol maser luminosity function in the Milky Way. The most
likely explanation for the absence of detectable methanol masers appears to be
the metallicity of M33, which is modestly less than that of the Milky Way
Bose-Einstein Condensation on a Permanent-Magnet Atom Chip
We have produced a Bose-Einstein condensate on a permanent-magnet atom chip
based on periodically magnetized videotape. We observe the expansion and
dynamics of the condensate in one of the microscopic waveguides close to the
surface. The lifetime for atoms to remain trapped near this dielectric material
is significantly longer than above a metal surface of the same thickness. These
results illustrate the suitability of microscopic permanent-magnet structures
for quantum-coherent preparation and manipulation of cold atoms.Comment: 4 pages, 6 figures, Published in Phys. Rev. A, Rapid Com
Bose-Einstein Condensation on a Permanent-Magnet Atom Chip
We have produced a Bose-Einstein condensate on a permanent-magnet atom chip
based on periodically magnetized videotape. We observe the expansion and
dynamics of the condensate in one of the microscopic waveguides close to the
surface. The lifetime for atoms to remain trapped near this dielectric material
is significantly longer than above a metal surface of the same thickness. These
results illustrate the suitability of microscopic permanent-magnet structures
for quantum-coherent preparation and manipulation of cold atoms.Comment: 4 pages, 6 figures, Published in Phys. Rev. A, Rapid Com
Supported Decision-Making for People Living with Dementia: An Examination of Four Australian Guardianship Laws
Australia is obliged under the Convention on the Rights of Persons with Disabilities to provide decision-making support to people with cognitive impairment. While there has been considerable recent activity looking at how the law should respond to the challenges raised by the Convention, there has been little discussion in Australia of how these changes will impact upon the care of people with dementia (the largest class of person with cognitive impairment in Australia). This section examines current Australian legal approaches to decision-making for people with dementia in four jurisdictions (New South Wales, South Australia, Victoria and Western Australia) through an analysis of reported tribunal decisions in each of these jurisdictions. It notes the scope for informal supported decision-making and the basis for the invocation of guardianship orders, including the new Victorian supportive guardianship order, and compares the new standards raised by the Convention. The section considers legal reforms which could improve the implementation of supported decision-making for people living with dementia
Fraud and error in financial, welfare and revenue services: a systematic map of the empirical research evidence with particular reference to 'notification of changes of circumstances'
The Department for Work and Pensions (DWP) recognises that, in order to meet its strategic objectives, it is crucial to pay the right amount of benefit to the right person at the right time. During 2008/09, the DWP spent approximately £135.6 billion on benefits, of which it is estimated that about two per cent (£2.7 billion) was overpaid due to fraud and error. Recent estimates suggest
that there were about £550 million of overpayments of Income Support (IS) and Jobseeker’s Allowance (JSA) (about five per cent of total spending on this type of benefit), £770 million on Housing Benefit (HB) (about 4.5 per cent of the total) and £340 million on Pension Credit (about 4.6 per cent of the total). Despite the increased measures undertaken to reduce fraud and error in the
benefit system, the DWP acknowledges that new strategies for improving correctness of benefit payments are a priority. / In the light of this official commitment to reducing overpayments, there is considerable interest in the process of notifying a ‘change of circumstances (CoCs)’ and in potential strategies to reduce fraud and
error. This project aimed to identify and describe existing research literature on issues within related
fields of financial products/services, welfare provision, taxation, and tax credit systems. / This review is part of a wider programme of systematic review work commissioned by the DWP and carried out by the EPPI-Centre
- …