11,340 research outputs found
Thermally-driven Neutron Star Glitches
We examine the thermal and dynamical response of a neutron star to a sudden
perturbation of the inner crust temperature. During the star's evolution,
starquakes and other processes may deposit \gap 10^{42} ergs, causing
significant internal heating and increased frictional coupling between the
crust and the more rapidly rotating neutron superfluid the star is expected to
contain. Through numerical simulation we study the propagation of the thermal
wave created by the energy deposition, the induced motion of the interior
superfluid, and the resulting spin evolution of the crust. We find that energy
depositions of ergs produce gradual spin-ups above the timing
noise level, while larger energy depositions produce sudden spin jumps
resembling pulsar glitches. For a star with a temperature in the observed range
of the Vela pulsar, an energy deposition of ergs produces a
large spin-up taking place over minutes, similar to the Vela ``Christmas''
glitch. Comparable energy deposition in a younger and hotter ``Crab-like'' star
produces a smaller spin-up taking place over day, similar to that seen
during the partially time-resolved Crab glitch of 1989.Comment: 21 pages plus 17 figures, uuencode compressed Postscript. Accepted
for publication in the Astrophysical Journa
1E 1207.4-5209: a low-mass bare strange star?
Both rotation- and accretion-powered low-mass bare strange stars are studied,
the astrophysical appearances of which are especially focused. It is suggested
that low-mass bare strange stars, with weaker ferromagnetic fields than that of
normal pulsars, could result from accretion-induced collapses (AIC) of white
dwarfs. According to its peculiar timing behavior, we propose that the
radio-quiet object, 1E 1207.4-5209, could be a low-mass bare strange star with
polar surface magnetic field ~ 6 x 10^10 G and a few kilometers in radius. The
low-mass bare strange star idea is helpful to distinguish neutron and strange
stars, and is testable by imaging pulsar-like stars with the future
Constellation-X telescope.Comment: 13 pages, 4 figures, 1 table; changed significantly, a section "quark
matter phenomenology" added; accepted by MNRA
Veterinary treatment in organic husbandry
The organic farming regulations put emphasis on the preservation of animal health by prophylaxis in the agriculture. The No 5 of the regulation EC 1804/99 (EC organic regulation) Appendix I B defines the veterinary treatments in organic animal husbandry. The veterinarian can use any medicine, which is effective for the indication and the animal species. If possible, effective homeopathics, phytotherapeutics or the like should have priority.
Problems of implementing the EC organic regulation into the daily farm practice arise mostly from the doubling of the withdrawal period and the restriction of the numbers of treatments. The strict ban on prophylactic treatments is not mentioned any longer in the new regulation 834/2007, which shall apply as from 1st January 2009.
Clarification of the guidelines for animal treatments in organic farming seems to be useful for farmers, veterinarians and boards of control
Probing Active to Sterile Neutrino Oscillations in the LENS Detector
Sterile neutrino conversion in meter scale baselines can be sensitively
probed using monoenergetic, sub-MeV, flavor pure e-neutrinos from an artificial
MCi source and the unique technology of LENS designed to oberve the low energy
solar neutrino spectrum via tagged CC e-neutrino capture in 115-In.
Active-sterile oscillations can be directly observed in the granular LENS
detector itself to critically test and extend resuls of short baseline
accelerator and reactor experiments.Comment: 4pages, 4 figures, text and figure change
"Who receives statins? Variations in physiciansâ prescribing patterns for patients with coronary heart disease, dyslipidemia, and diabetes"
Our objective is to estimate the extent to which clinical and non-clinical factors are associated with physiciansâ prescribing patterns for statins. The data are from the National Ambulatory Medical Care Survey for the period 1992 through 2004. The three samples examined included more than 14,000 patients who were diagnosed with coronary heart disease, high cholesterol, or diabetes, individuals who are most likely to benefit from being prescribed a statin drug. Using a multinomial logit framework, we find disparities in prescribing patterns based on non-clinical factors. Namely, whites and patients who have private insurance are more likely to be prescribed a statin than nonwhites and those with public insurance. Also, even though a large increase occurred in the uptake of statins over the period 1992 to 2004, our results for 2004 show that only about 50 percent of patients diagnosed with coronary heart disease were prescribed a statin. Because coronary heart disease is the leading cause of death in the U.S. and currently is estimated to cost over $150 billion annually in the U.S. in direct and indirect costs, observed differences in prescribing patterns along these dimensions is troubling and should be part of discussions dealing with health care reform.Pharmaceuticals; Statins; Equity in Physician Prescribing Patterns; Insurance
PSR B1828-11: a precession pulsar torqued by a quark planet?
The pulsar PSR B1828-11 has long-term, highly periodic and correlated
variations in both pulse shape and the rate of slow-down. This phenomenon may
provide evidence for precession of the pulsar as suggested previously within
the framework of free precession as well as forced one. On a presumption of
forced precession, we propose a quark planet model to this precession henomenon
instead, in which the pulsar is torqued by a quark planet. We construct this
model by constraining mass of the pulsar (), mass of the planet
() and orbital radius of the planet (). Five aspects
are considered: derived relation between and ,
movement of the pulsar around the center of mass, ratio of and
, gravitational wave radiation timescale of the planetary system,
and death-line criterion. We also calculate the range of precession period
derivative and gravitational wave strength (at earth) permitted by the model.
Under reasonable parameters, the observed phenomenon can be understood by a
pulsar () with a quark planet
() orbiting it. According to the calculations
presented, the pulsar would be a quark star because of its low mass, which
might eject a lump of quark matter (to become a planet around) during its
birth.Comment: 6 pages, 3 figures, accepted by MNRAS (Letters
Recommended from our members
Elephantiasis nostras verrucosa: an atypical presentation following intrapelvic lymphoma
Elephantiasis nostras verrucosa is a progressively debilitating and disfiguring disease commonly presenting with verrucous, cobblestone-like papules, nodules, or plaques with nonpitting edema in the lower extremities. Histopathology is marked by hyperkeratosis and dermal or subcutaneous fibrosis as a result of chronic lymphedema. Risk factors include obesity, recurrent cellulitis, chronic venous insufficiency, congestive heart failure, scleroderma, radiation, trauma, and tumors. We report a 72-year-old man who presented to the dermatology clinic for an 11-year history of edematous legs, occasionally associated with ulcerations. The findings developed within a year of intrapelvic non-Hodgkin lymphoma and progressed gradually over 10 years after lymphoma remission. Physical examination revealed atypical features including compressible cysts and pitting edema extending from the lower legs to the thighs bilaterally. The patient was noncompliant for the recommended compressive devices and the condition progressively worsened over the course of 7 months of follow-up. Early interdisciplinary management using compressive devices and a lymphatic pump are recommended. Underlying causative factors should be assessed with regular follow-up to optimize treatment outcomes
Erfahrungen aus dem Stadtarchiv MĂŒnster mit dem Wettbewerb Deutsche Geschichte um den Preis des BundesprĂ€sidenten
Usage of UITS advanced research cyberinfrastructure for 2011
IU has a proud tradition in open access to its research computing and cyberinfrastructure (CI) facilities, going back to the precedents set by Marshall Wrubel (appointed the first permanent director of the IU Research Computing Center in 1955). Starting in 1997 President Myles Brand and then-Vice President Michael McRobbie initiated a tremendous acceleration in growth of IUâs cyberinfrastructure facilities through developing and then executing the first Indiana University Information Technology Strategic Plan. Through a decade and a half of purposeful execution of excellent strategies in support for research and scholarly activities generally, University Information Technology Services (UITS) has provided exceptional support to a group of researchers. This includes usage from disciplines that are among the traditional users of high performance computing â physics, chemistry, and astronomy, as well as emerging areas of application of HPC including biology, business, and the arts
Letter From the Editor
One of my first responsibilities as the Journal\u27s 1996-97 editor in chief was to ask Professor John Paul Jones to serve as our faculty advisor. I made this request over dinner one evening late in the summer of 1996, and while he declined to commit (we eventually reached an agreement), he did make a very interesting observation. Being only the second editorial board in the Journal\u27s brief history, Prof. Jones said it appeared as though I and the rest of the board were being asked to clean up after the revolution. He and I both found his comment amusing, since given a choice, I (and the balance of my fellow board members, for that matter) would have much rather preferred to be a member of the revolution than one who institutes and perpetuates its effects
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