11,589 research outputs found
Automatic analysis of Swift-XRT data
The Swift spacecraft detects and autonomously observes ~100 Gamma Ray Bursts
(GRBs) per year, ~96% of which are detected by the X-ray telescope (XRT). GRBs
are accompanied by optical transients and the field of ground-based follow-up
of GRBs has expanded significantly over the last few years, with rapid response
instruments capable of responding to Swift triggers on timescales of minutes.
To make the most efficient use of limited telescope time, follow-up astronomers
need accurate positions of GRBs as soon as possible after the trigger.
Additionally, information such as the X-ray light curve, is of interest when
considering observing strategy. The Swift team at Leicester University have
developed techniques to improve the accuracy of the GRB positions available
from the XRT, and to produce science-grade X-ray light curves of GRBs. These
techniques are fully automated, and are executed as soon as data are available.Comment: 4 pages, 2 figures, to appear in the proceedings of ADASS XVII (ASP
Conference Series
Evaluating coasean bargaining experiments with meta-analysis
While the Coase Theorem has been a touchstone for understanding bargaining behavior, it has also been criticized for relying on unrealistic assumptions. In response, a line of experimental research analyzes bargaining behavior in laboratory settings. This paper uses meta-analysis to evaluate the Coasean bargaining literature by modeling the probability of an efficient bargain as a function of: (1) measures of transaction costs and related variables, and (2) measures of the social dimensions of a bargain. Results suggest that efficient solutions are more likely when explicit transaction costs do not exist, in the absence of a binding time limit, and when participants have perfect information on payoff schedules. Social dimension variables are found to have the potential to affect bargaining outcomes and are an important avenue for further research.Coase Theorem
Inversion of spinning sound fields
A method is presented for the reconstruction of rotating monopole source
distributions using acoustic pressures measured on a sideline parallel to the
source axis. The method requires no \textit{a priori} assumptions about the
source other than that its strength at the frequency of interest vary
sinusoidally in azimuth on the source disc so that the radiated acoustic field
is composed of a single circumferential mode. When multiple azimuthal modes are
present, the acoustic field can be decomposed into azimuthal modes and the
method applied to each mode in sequence.
The method proceeds in two stages, first finding an intermediate line source
derived from the source distribution and then inverting this line source to
find the radial variation of source strength. A far-field form of the radiation
integrals is derived, showing that the far field pressure is a band-limited
Fourier transform of the line source, establishing a limit on the quality of
source reconstruction which can be achieved using far-field measurements. The
method is applied to simulated data representing wind-tunnel testing of a
ducted rotor system (tip Mach number~0.74) and to control of noise from an
automotive cooling fan (tip Mach number~0.14), studies which have appeared in
the literature of source identification.Comment: Revised version of paper submitted to JASA; five more figures;
expanded content with more discussion of error behaviour and relation to
Nearfield Acoustical Holograph
Helical recorder
Tape recorder, using metallic tape, has a minimum of moving parts and no belts. It permits long-term bulk storage in extreme environments, and has less weight and bulk than present recording equipment
Ferromagnetically coupled dimers on the distorted Shastry-Sutherland lattice: Application to (CuCl)LaNb2O7
A recent study [Tassel {\it et al.}, Phys. Rev. Lett. {\bf 105}, 167205
(2010)] has proposed a remarkable spin model for (CuCl)LaNb2O7, in which dimers
are ferromagnetically coupled to each other on the distorted Shastry-Sutherland
lattice. In this model, the intra-dimer exchange coupling J>0 is
antiferromagnetic, while the inter-dimer exchange couplings are ferromagnetic
and take different values, J_x,J_y<0, in the two bond directions. Anticipating
that the highly frustrated character of this model may lead to a wide range of
behaviors in (CuCl)LaNb2O7 and related compounds, we theoretically investigate
the ground state phase diagram of this model in detail using the following
three approaches: a strong-coupling expansion for small J_x and J_y, exact
diagonalization for finite clusters, and a Schwinger boson mean field theory.
When |J_x|, |J_y| <~ J, the system stays in a dimer singlet phase with a finite
spin gap. This state is adiabatically connected to the decoupled-dimer limit
J_x=J_y=0. We show that the magnetization process of this phase depends
crucially on the spatial anisotropy of the inter-dimer couplings. The
magnetization shows a jump or a smooth increase for weak and strong anisotropy,
respectively, after the spin gap closes at a certain magnetic field. When |J_x|
or |J_y| >~ J, quantum phase transitions to various magnetically ordered phases
(ferromagnetic, collinear stripe, and spiral) occur. The Schwinger boson
analysis demonstrates that quantum fluctuations split the classical degeneracy
of different spiral ground states. Implications for (CuCl)LaNb2O7 and related
compounds are discussed in light of our theoretical results and existing
experimental data.Comment: 21 pages, 20 figure
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Author Correction: A cell-free platform for the prenylation of natural products and application to cannabinoid production.
In the original version of this Article, the genotype of the M30 mutant presented in Fig. 3b was given incorrectly as Y288V/A232S, and the M31 mutant was given incorrectly as M1/A232S. The correct genotype of the M30 mutant is Y288A/A232S and for M31 it is Y288V/A232S. In addition, to keep consistency in genotype formatting, the genotype of the M27 mutant should be Y288V/G286S. The errors have been corrected in both the PDF and HTML versions of the Article
The Value of Comparative Animal Research : Krogh’s Principle Facilitates Scientific Discoveries
There are no conflicts of interest to declare. This paper developed from the 2016 Early Career Impact Award from the Federation of Associations in Behavioral & Brain Sciences to TJS. TJS has received funding from The Leverhulme Trust. FJPE is in receipt of funding from the BBSRC (BB/M001555/1). The National Institutes of Health has funded RDF (NS 034950, NS093277, NIMH 087930), AGO (HD079573, IOS-1354760) and AMK (HD081959). BAA is an Arnold O. Beckman postdoctoral fellow.Peer reviewedPostprin
Athletic pubalgia and associated rehabilitation
BACKGROUND: Evaluation and treatment of groin pain in athletes is challenging. The anatomy is complex, and multiple pathologies often coexist. Different pathologies may cause similar symptoms, and many systems can refer pain to the groin. Many athletes with groin pain have tried prolonged rest and various treatment regimens, and received differing opinions as to the cause of their pain. The rehabilitation specialist is often given a non-specific referral of groin pain or sports hernia. The cause of pain could be as simple as the effects of an adductor strain, or as complex as athletic pubalgia or inguinal disruption. The term sports hernia is starting to be replaced with more specific terms that better describe the injury. Inguinal disruption is used to describe the syndromes related to the injury of the inguinal canal soft tissue environs ultimately causing the pain syndrome. The term athletic pubalgia is used to describe the disruption and/or separation of the more medial common aponeurosis from the pubis, usually with some degree of adductor tendon pathology. TREATMENT: Both non-operative and post-operative treatment options share the goal of returning the athlete back to pain free activity. There is little research available to reference for rehabilitation guidelines and creation of a plan of care. Although each surgeon has their own specific set of post-operative guidelines, some common concepts are consistent among most surgeons. Effective rehabilitation of the high level athlete to pain free return to play requires addressing the differences in the biomechanics of the dysfunction when comparing athletic pubalgia and inguinal disruption. CONCLUSION: Proper evaluation and diagnostic skills for identifying and specifying the difference between athletic pubalgia and inguinal disruption allows for an excellent and efficient rehabilitative plan of care. Progression through the rehabilitative stages whether non-operative or post-operative allows for a focused rehabilitative program. As more information is obtained through MRI imaging and the diagnosis and treatment of inguinal disruption and athletic pubalgia becomes increasingly frequent, more research is warranted in this field to better improve the evidence based practice and rehabilitation of patients. LEVELS OF EVIDENCE: 5
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