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Background: The reproducibility and repeatability of modern systems for classification of thoracolumbar injuries have not been sufficiently studied. We assessed the interobserver and intraobserver reproducibility of the AO (Arbeitsgemeinschaft fur Osteosynthesefragen) classification and compared it with that of the Denis classification. Our purpose was to determine whether the newer, AO system had better reproducibility than the older, Denis classification. Methods: Anteroposterior and lateral radiographs and computerized tomography scans (axial images and sagittal reconstructions) of thirty-one acute traumatic fractures of the thoracolumbar spine were presented to nineteen observers, all trained spine surgeons, who classified the fractures according to both the AO and the Denis classification systems. Three months later, the images of the thirty-one fractures were scrambled into a different order, and the observers repeated the classification. The Cohen kappa (κ) test was used to determine interobserver and intraobserver agreement, which was measured with regard to the three basic classifications in the AO system (types A, B, and C) as well as the nine subtypes of that system. We also measured the agreement with regard to the four basic types in the Denis classification (compression, burst, seat-belt, and fracture-dislocation) and with regard to the sixteen subtypes of that system. Results: The AO classification was fairly reproducible, with an average kappa of 0.475 (range, 0.389 to 0.598) for the agreement regarding the assignment of the three types and an average kappa of 0.537 for the agreement regarding the nine subtypes. The average kappa for the agreement regarding the assignment of the four Denis fracture types was 0.606 (range, 0.395 to 0.702), and it was 0.173 for agreement regarding the sixteen subtypes. The intraobserver agreement (repeatability) was 82% and 79% for the AO and Denis types, respectively, and 67% and 56%, for the AO and Denis subtypes, respectively. Conclusions: Both the Denis and the AO system for the classification of spine fractures had only moderate reliability and repeatability. The tendency for well-trained spine surgeons to classify the same fracture differently on repeat testing is a matter of some concern.

Loop quantum cosmology leads to a difference equation for the wave function of a universe, which in general has solutions changing rapidly even when the volume changes only slightly. For a semiclassical regime such small-scale oscillations must be suppressed, by choosing the parameters of the solution appropriately. For anisotropic models this is not possible to do numerically by trial and error; instead, it is shown here for the Bianchi I LRS model how this can be done analytically, using generating function techniques. Those techniques can also be applied to more complicated models, and the results gained allow conclusions about initial value problems for other systems., Comment: 22 pages, 5 figures; version to appear in CQG

Treating the Teukolsky perturbation equation numerically as a 2+1 PDE and smearing the singularities in the particle source term by the use of narrow Gaussian distributions, we have been able to reproduce earlier results for equatorial circular orbits that were computed using the frequency domain formalism. A time domain prescription for a more general evolution of nearly geodesic orbits under the effects of radiation reaction is presented. This approach can be useful when tackling the more realistic problem of a stellar-mass black hole moving on a generic orbit around a supermassive black hole under the influence of radiation reaction forces., 8 pages, 5 figures, problems with references and double-printing fixed

A study was carried out on the dehydration behaviour, texture, color and sensory acceptability of mango leather. Soy protein concentrate, skim milk powder and sucrose were added at levels of 0%, 4.5% and 9% to improve nutritive value and sweetness of the product. It took 7.60 h of drying time at 60±1°C for mango leather to reach 10% moisture content (wb). The three ingredients lowered the drying rate of mango leather with soy protein concentrate having the most significant effect followed by sucrose and skim milk powder. An objective method for studying the texture of mango leather is presented. The mango leather had an extensibility and energy to rupture of 10.71 mm and 0.1503 J and the extensibility and energy to rupture decreased with increasing levels of soy protein concentrate, skim milk powder and sucrose. Mango leather had L, a and b values of 42.58, 12.58 and 26.89. The yellowness of mango leather as indicated by b values decreased with increase in soy protein concentrate and increased with increase in sucrose. Soy protein concentrate lowered the sensory acceptability of mango leather whereas sucrose and skim milk powder at levels of 4.5% each resulted in mango leather with the highest acceptability. A regression model was developed and coefficients had high R2 values (>0.85) and can be used to predict texture, color, drying time and sensory acceptability.

Cr(001)/CoCrPt (1120) films, used in magnetic hard disks, exhibit in-plane magnetic anisotropy when grown over a substrate patterned with shallow grooves. In this experiment, Cr/CoCrPt films are grown over substrates that have been patterned using lithographic techniques to produce well-controlled topography. The in-plane anisotropy, which is of the order of 104 J m−3, increases with the groove height and frequency. This magnetic anisotropy is a result of anisotropic in-plane crystallographic orientation and anisotropic stress. Stress-induced anisotropy accounts for up to 25% of the total in-plane anisotropy, but the major contribution to the anisotropy is a preferential Co c-axis alignment parallel to the groove direction.

The recent detection of gravitational waves has generated interest in alternatives to the black hole interpretation of sources. One set of such alternatives involves a prediction of gravitational wave "echoes". We consider two aspects of possible echoes: First, general features of echoes coming from spacetime reflecting conditions. We find that the detailed nature of such echoes does not bear any clear relationship to quasi-normal frequencies. Second, we point out the pitfalls in the analysis of local reflecting "walls" near the horizon of rapidly rotating black holes., 8 pages, 4 figures; to appear in Classical & Quantum Gravity (CQG)

Advancement in technology has resulted in increased computing power with the use of multiple processors within a system. These multiple processors need to communicate with each other and with memory modules. Multistage Interconnection Networks (MINs) provide a communication medium in such multi-processor systems by interconnecting a number of processors and memory modules. Besides, MINs also provide a cost effective substitute to costly crossbars in parallel computers and switching systems in telephone industry. This paper introduces two new fault-tolerant MINs named as Shuffle Exchange Gamma Interconnection Networks (SEGIN-1 and SEGIN-2). SEGIN-1 and SEGIN-2 can be obtained by altering Shuffle Exchange Network with one extra stage (SEN+) and provide two disjoint paths similar to it. Performance of SEGIN-1 and SEGIN-2 has been evaluated in terms of alternative paths, disjoint paths, reliability and hardware cost, and is compared with some very famous MINs like Shuffle Exchange Network (SEN), Shuffle Exchange Network with one extra stage (SEN+), Shuffle Exchange Network with two extra stage (SEN+2), Extra Stage Cube (ESC) and Gamma Interconnection Network (GIN). Results suggest that SEGINs surpass all the compared networks; hence, the proposed designs seem to be suitable for implementing practical interconnection networks.

Understanding the impact that increased high-skilled immigration has had on a country's economy involves evaluating counter-factuals—what would the economy have been like under a more restrictive immigration policy? We modeled decisions made by U.S. firms and workers, then used the introduction of

Mixed phenotypic acute leukemia (MPAL) is a rare clinical entity. MPAL associated with myeloidsarcoma (MS) is still rarer with only three cases mentioned in English literature. MS has been described in myriads of location, most commonly in skin, gums and lymph nodes. Although theoritically possible, it is very rare to find MS involving the thyroid gland. The diagnosis of MS can be elusive, very often masquerades and mislabeled as lymphoma. A high index of clinical suspicion coupled with PET/CT findings along with morphological clues and thorough peripheral blood, and bone marrow evaluation is mandatory for arriving at the definitive diagnosis. We report the case of a 58-year-old female presenting with thyroid swelling that was subsequently diagnosed to be MS of the thyroid with underlying MPAL (mixed myeloid/B-cell) only after 18F-FDG PET/CT, which revealed an unusual abnormal pattern of multifocal intense FDG uptake in the thyroid gland.

We numerically solve the Teukolsky equation in the time domain to obtain the gravitational-wave emission of a small mass inspiraling and plunging into the equatorial plane of a Kerr black hole. We account for the dissipation of orbital energy using the Teukolsky frequency-domain gravitational-wave fluxes for circular, equatorial orbits, down to the light-ring. We consider Kerr spins $-0.99 \leq q \leq 0.99$, and compute the inspiral-merger-ringdown (2,2), (2,1), (3,3), (3,2), (4,4), and (5,5) modes. We study the large-spin regime, and find a great simplicity in the merger waveforms, thanks to the extremely circular character of the plunging orbits. We also quantitatively examine the mixing of quasinormal modes during the ringdown, which induces complicated amplitude and frequency modulations in the waveforms. Finally, we explain how the study of small mass-ratio black-hole binaries helps extending effective-one-body models for comparable-mass, spinning black-hole binaries to any mass ratio and spin magnitude., 20 pages, 15 figures

The Indian state faces a substantial internal security threat in the form of a Maoist insurgency, but decades of relying predominantly on military strength have not been a successful strategy for resolving the conflict. Recently, there has been a growing interest in whether anti-poverty programs can increase the effectiveness of the government forces by improving the relationship between citizens and the state and making civilians more willing to share information on insurgents. A prime candidate for such a program is the National Rural Employment Guarantee Scheme (NREGS), the world’s largest public-works program. We find that the introduction of NREGS leads to an increase in violence in the short run that is driven by police-initiated attacks, and an increase in the number of captured Maoists. These results are consistent with the hypothesis that civilians assist the police because of NREGS, and suggest that the role of civilians in internal conflicts should not be ignored.

The numerical investigation of wave propagation in the asymptotic domain of Kerr spacetime has only recently been possible thanks to the construction of suitable hyperboloidal coordinates. The asymptotics revealed an apparent puzzle in the decay rates of scalar fields: the late-time rates seemed to depend on whether finite distance observers are in the strong field domain or far away from the rotating black hole, an apparent phenomenon dubbed "splitting". We discuss far-field "splitting" in the full field and near-horizon "splitting" in certain projected modes using horizon-penetrating, hyperboloidal coordinates. For either case we propose an explanation to the cause of the "splitting" behavior, and we determine uniquely decay rates that previous studies found to be ambiguous or immeasurable. The far-field "splitting" is explained by competition between projected modes. The near-horizon "splitting" is due to excitation of lower multipole modes that back excite the multipole mode for which "splitting" is observed. In both cases "splitting" is an intermediate effect, such that asymptotically in time strong field rates are valid at all finite distances. At any finite time, however, there are three domains with different decay rates whose boundaries move outwards during evolution. We then propose a formula for the decay rate of tails that takes into account the inter--mode excitation effect that we study., Comment: 16 pages

We consider the decay rate for scalar fields in Kerr spacetime. We consider pure initial (azimuthal) multipoles $\ell'$ with respect to the class which includes Boyer-Lindquist coordinates, and focus attention on the decay rate of the multipole $\ell$. We use an iterative method proposed by Gleiser, Price, and Pullin, and identify the mode coupling mechanism through the iterations in powers of the square of the Kerr black hole's specific angular momentum that gives rise to a decay rate formula recently proposed by Zengino\u{g}lu, Khanna, and Burko. Modes $\ell$ may be excited through different channels, each leading to its own decay rate. The asymptotic decay rate of the mode $\ell$ is the slowest of the decay rate of the various channels. In some cases, more than one channel leads to the same decay rate, and then the amplitude of the mode is the sum of the amplitudes of the partial fields generated by the individual channels. We also show that one may identify the asymptotically-dominant channel of mode excitations, and obtain approximate results for the mode of interest by studying the dominant channel. The results of the dominant channel approximation approach the full-mode results at late times, and their difference approaches zero quadratically in inverse time., Comment: 22 pages, 12 figures, 4 tables

Most estimates of the economic impacts of transit networks compare regions along network routes to neighboring regions away from such routes. However, in the presence of spatial spillovers in economic activity such a method will underestimate the true effect of roads and railways. In this paper, I take into account spatial spillovers in estimating the overall impacts of transit networks in India. I use an empirical strategy relying on the historical placement of major cities: by connecting nodal cities with straight lines, I instrument for the endogenous placement of these networks. Using night-time luminosity data as a measure of economic activity, I estimate the parameters of a predictive model that incorporates these spillovers, which then performs well in an out-of-sample exercise. I find that being close to transit networks between cities led to greater economic activity in the 1990s and that such activity spread to neighboring regions, substantially increasing the overall impacts. Ignoring the spillovers produces income elasticities that are only 27% of the true overall effects of such routes. These geographic externalities led to a rapid rate of convergence in incomes across regions, highlighting how transit networks and spatial spillovers together, strongly determined the geographic spread and temporal changes in the economic development of the region.

The epitaxial growth of aluminum [111] by sputtering deposition on Ni 80 Fe 20 [111] has been demonstrated, despite the large 12.2% lattice mismatch in this system. The absence of high angle grain boundaries in epitaxial films would lead to thinner, smoother and more uniform barrier layers in spin-dependent tunneling junctions. The strain evolution was monitored by in-situ reflection high-energy electron diffraction, and grazing incidence X-ray scattering diffraction was used to verify the epitaxial growth. The aluminum film after natural oxidation was extremely smooth, with an rms roughness of 0.2 nm as measured by atomic force microscopy.

Gravitational waves emitted during the inspiral, plunge and merger of a black hole binary carry linear momentum. This results in an astrophysically important recoil to the final merged black hole, a ``kick'' that can eject it from the nucleus of a galaxy. In a previous paper we showed that the puzzling partial cancellation of an early kick by a late antikick, and the dependence of the cancellation on black hole spin, can be understood from the phenomenology of the linear momentum waveforms. Here we connect that phenomenology to its underlying cause, the spin-dependence of the inspiral trajectories. This insight suggests that the details of plunge can be understood more broadly with a focus on inspiral trajectories., Comment: 15 pages, 12 figures

We consider the importance of the second-order dissipative self force for gravitational wave dephasing for an extreme or intermediate mass ratio system moving along a quasi-circular Schwarzschild orbit. For the first-order self force we use the fully relativistic force in the Lorenz gauge for eternally circular geodesics. The second-order self force is modeled by its 3.5 post Newtonian counterpart. We evolve the system using the osculating orbits method, and obtain the gravitational waveforms, whose phase includes all the terms - within our approximation (and using the self force along circular geodesics) - that are independent of the system's mass ratio. The partial dephasing due to the second-order dissipative self force is substantially smaller than that of the first-order conservative self force, although they are both at the same order in the mass ratio., 8 pages, 10 figures, accepted to Phys. Rev. D. Version 2 includes elaboration of the justification for the model used and for the gauge invariance of our results, and correction of typos

1Pulmonary, Critical Care and Sleep Medicine Division, University of Cincinnati College of Medicine, Cincinnati, Ohio; 2Gastroenterology and Hepatology Division, Baylor College of Medicine, Houston, Texas, USA Correspondence: Dr Muhammad A Zafar, Pulmonary, Critical Care and Sleep Medicine Division, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, Ohio 45229, USA. Telephone 513-827-2345, e-mail zafarmd@ucmail.uc.edu A 58-year-old woman with morbid obesity, diabetes and rheumatoid arthritis was admitted to the intensive care unit with septic shock due to an infected knee that required surgical irrigation and drainage. Postoperatively, she developed hypercarbic respiratory failure necessitating emergent reintubation. Three hours later, a tense swelling with crepitus was noticed on her neck and chest. A computed tomography scan of her chest revealed massive subcutaneous emphysema, pneumomediastinum and pneumothorax due to a tracheal laceration (Figures 1 to 3). She was emergently taken to the operative room. Flexible bronchoscopy showed a posterior tracheal perforation just above the carina. Right thoracotomy revealed a 2 cm tear in the membranous trachea extending toward the right main stem bronchus, which was repaired. After a prolonged stay in the intensive care unit, the patient died due to multiorgan failure and gastrointestinal bleeding. iMages in respiratory Medicine

We propose an improved analytical model for the horizon-absorbed gravitational-wave energy flux of a small body in circular orbit in the equatorial plane of a Kerr black hole. Post-Newtonian (PN) theory provides an analytical description of the multipolar components of the absorption flux through Taylor expansions in the orbital frequency. Building on previous work, we construct a mode-by-mode factorization of the absorbed flux whose Taylor expansion agrees with current PN results. This factorized form significantly improves the agreement with numerical results obtained with a frequency-domain Teukolsky code, which evolves through a sequence of circular orbits up to the photon orbit. We perform the comparison between model and numerical data for dimensionless Kerr spins $-0.99 \leq q \leq 0.99$ and for frequencies up to the light ring of the Kerr black hole. Our proposed model enforces the presence of a zero in the flux at an orbital frequency equal to the frequency of the horizon, as predicted by perturbation theory. It also reproduces the expected divergence of the flux close to the light ring. Neither of these features are captured by the Taylor-expanded PN flux. Our proposed absorption flux can also help improve models for the inspiral, merger, ringdown of small mass-ratio binary systems.

I study the impacts of affirmative action policies on schooling incentives in India. My results indicate that when the probability of getting into college or of getting a job is increased through affirmative action, minority group students are incentivized to stay in school longer given the prospects of directly benefiting from such policies in the near future. This approach is unique, in that it focuses on the incentives affirmative action gives to those who are not yet eligible for the policy per se. I create a comprehensive primary dataset using state commission reports which allows for a regression discontinuity and difference-in-discontinuities analysis. These results are supported at the national level by using a difference-in-differences approach, and utilizing variation in state-level policies. Together these estimators consistently show that affirmative action policies incentivize about 1.38 more years of education for the average minority group student, and 2.2 more years of education for a student from a marginal minority sub-group. Given the debate about the effectiveness of such policies, my research shows that it is particularly important for both researchers and policy makers to take into account these incentive effects when evaluating affirmative action programs.

We present a GPU accelerated numerical solver for incompressible, immiscible, two-phase fluid flows. This leads to a significant simulation speed-up and thus, the capability to have finer grid sizes and/or more accurate convergence criteria. We solve the Navier-Stokes equations, which include the surface tension force, by using a two-step projection method requiring the iterative solution to a pressure Poisson problem at each time step. However, running a serial linear algebra solver on a CPU to solve the pressure Poisson problem can take 50–99.9% of the total simulation time. To remove this bottleneck, we employ the large parallelization capabilities of GPUs by developing a double-precision parallel linear algebra solver, SCGPU, using NVIDIA’s CUDA v.4.0 libraries. The performance of SCGPU in serial simulations is presented, in addition to an evaluation of two pre-packaged GPU linear algebra solvers CUSP and CULA-sparse. We also present preliminary results of a GPU-accelerated MPI CPU flow solver.Copyright © 2012 by ASME

In this article, we review the use of numerical techniques to obtain solutions for the quantum Hamiltonian constraint in loop quantum cosmology (LQC). First, we summa- rize the basic features of LQC, and describe features of the constraint equations to solve { generically, these are difference (rather than differential) equations. Important issues such as differing quantization methods, stability of the solutions, the semi-classical limit, and the relevance of lattice refinement in the difference equations are discussed. Finally, the cosmo- logical models already considered in the literature are listed, along with typical features in these models and open issues.

Using the effective-one-body (EOB) formalism and a time-domain Teukolsky code, we generate inspiral, merger, and ringdown waveforms in the small mass-ratio limit. We use EOB inspiral and plunge trajectories to build the Teukolsky equation source term, and compute full coalescence waveforms for a range of black hole spins. By comparing EOB waveforms that were recently developed for comparable mass binary black holes to these Teukolsky waveforms, we improve the EOB model for the (2,2), (2,1), (3,3), and (4,4) modes. Our results can be used to quickly and accurately extract useful information about merger waves for binaries with spin, and should be useful for improving analytic models of such binaries., 19 pages, 14 figures, 6 tables. Minor revisions (results unchanged) to match version published in PRD

There is a strong need for high-accuracy and efficient modeling of extreme-mass-ratio binary black hole systems because these are strong sources of gravitational waves that would be detected by future observatories. In this article, we present sample results from our Teukolsky EMRI code: a time-domain Teukolsky equation solver (a linear, hyperbolic, partial differential equation solver using finite-differencing), that takes advantage of several mathematical and computational enhancements to efficiently generate long-duration and high-accuracy EMRI waveforms. We emphasize here the computational advances made in the context of this code. Currently there is considerable interest in making use of many-core processor architectures, such as Nvidia and AMD graphics processing units (GPUs) for scientific computing. Our code uses the Open Computing Language (OpenCL) for taking advantage of the massive parallelism offered by modern GPU architectures. We present the performance of our Teukolsky EMRI code on multiple modern processor architectures and demonstrate the high level of accuracy and performance it is able to achieve. We also present the code's scaling performance on a large supercomputer i.e. NSF's XSEDE resource: Keeneland (a 201 TeraFLOP/s, 120-node HP SL390 system with 240 Intel Xeon 5660 CPUs and 360 NVIDIA Fermi M2070 graphics processors, with the nodes connected by an InfiniBand QDR network)., Comment: 8 pages; to appear in NSF XSEDE12

This paper reviews evidence from 44 middle-income countries on how the recent financial crisis affected jobs and workers' incomes. In addition to providing a rare assessment of the magnitude of the impact across several middle-income countries, the paper describes how labor markets adjusted and how the adjustments varied for different types of countries. The main finding is that the crisis affected the quality of employment more than the number of jobs. Overall, the slow-down in earning growth was considerably higher than that in employment, and the decline in gross domestic product was associated with a sharp decline in output per worker, particularly in the industrial sector. In several counties, hours per worker declined and hourly wages changed little. But both the magnitude and nature of the adjustments varied considerably across countries. For a given drop in gross domestic product, earnings declined more in countries with larger manufacturing sectors, smaller export sectors, and more stringent labor market regulations. In addition, overall employment became more sensitive to growth in gross domestic product. These findings have implications that go beyond the recent financial crisis as they highlight (i) the limitations of focusing policy responses on maintaining jobs and providing alterative employment or replacement income for the unemployed, and (ii) the critical role of fast-track data systems that are capable of monitoring ongoing labor market adjustment during economic downturns, in supporting the design of effective policy responses.

We describe the hyperboloidal compactification for Teukolsky equations in Kerr spacetime. We include null infinity on the numerical grid by attaching a hyperboloidal layer to a compact domain surrounding the rotating black hole and the orbit of an inspiralling point particle. This technique allows us to study, for the first time, gravitational waveforms from large- and extreme-mass-ratio inspirals in Kerr spacetime extracted at null infinity. Tests and comparisons of our results with previous calculations establish the accuracy and efficiency of the hyperboloidal layer method., 14 pages, 7 figures

A classical thought-experiment to destroy black holes was envisaged by Wald in 1974: it consists of throwing particles with large angular momentum into an extremal black hole, checking whether their capture can over-spin the black hole past the extremal limit and create a naked singularity. Wald showed that in the test-particle limit, particles that would be otherwise capable of producing naked singularities are simply scattered. Recently Jacobson and Sotiriou showed that if one considers instead a black hole that is almost, but not exactly extremal, then in the absence of backreaction effects particle capture could indeed over-spin the spacetime above the Kerr limit. Here we analyze back-reaction effects and show that for some of the trajectories giving rise to naked singularities, radiative effects can be neglected. However, for these orbits the conservative self-force is important, and seems to have the right sign to prevent the formation of naked singularities., 13 pages, 1 table, 3 figures. Expanded discussion of the photon limit of the dissipative and conservative self-force, references added. Accepted for publication in PRD (in press)

During the inspiral and merger of black holes, the interaction of gravitational wave multipoles carries linear momentum away, thereby providing an astrophysically important recoil, or "kick" to the system and to the final black hole remnant. It has been found that linear momentum during the last stage (quasinormal ringing) of the collapse tends to provide an "antikick" that in some cases cancels almost all the kick from the earlier (quasicircular inspiral) emission. We show here that this cancellation is not due to peculiarities of gravitational waves, black holes, or interacting multipoles, but simply to the fact that the rotating flux of momentum changes its intensity slowly. We show furthermore that an understanding of the systematics of the emission allows good estimates of the net kick for numerical simulations started at fairly late times, and is useful for understanding qualitatively what kinds of systems provide large and small net kicks., 15 pages, 6 figures, 2 tables

Currently, neither well-defined nor standardized measurement techniques exist for assessing deformity of extra-articular scapular fractures. To properly evaluate these injuries, compare observations across studies, and make clinical decisions, a validated measurement protocol for evaluating scapular fractures is needed.We describe techniques to quantitatively characterize extra-articular scapular fracture deformity; evaluate the reliability of these characterizations in plain film radiographs and CT scans; and determine potential differences in the characterization of the deformity between the two imaging modalities.We evaluated injury radiographs and three-dimensional CT images of 45 patients with extra-articular scapular fracture. Techniques for measuring medial/lateral displacement, angulation, translation, glenopolar angle, and glenoid version were established and utilized in two trials, performed 6 weeks apart, by three observers. We determined descriptive statistics for each measurement parameter.Interobserver reliability based upon interclass correlation coefficients ranged from 0.36 to 0.76 for radiographs and from 0.48 to 0.87 for three-dimensional CT. Intraobserver reliability using Pearson r coefficient ranged from 0.60 to 0.75 for radiographs and 0.64 to 0.89 for three-dimensional CT. Both individual and pooled measurements for angulation and glenopolar angle were higher on three-dimensional CT versus radiographs.Our data suggest three-dimensional CT is more reliable than plain radiography in the assessment of scapula fracture displacement. Therefore, we believe this modality should be utilized if fracture deformity warrants surgical consideration and to adequately compare data across studies.Level IV, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Currently there is considerable interest in making use of many-core processor architectures, such as Nvidia and AMD graphics processing units (GPUs) for scientific computing. In this work we explore the use of the Open Computing Language (OpenCL) for a typical Numerical Relativity application: a time-domain Teukolsky equation solver (a linear, hyperbolic, partial differential equation solver using finite-differencing). OpenCL is the only vendor-agnostic and multi-platform parallel computing framework that has been adopted by all major processor vendors. Therefore, it allows us to write portable source-code and run it on a wide variety of compute hardware and perform meaningful comparisons. The outcome of our experimentation suggests that it is relatively straightforward to obtain order-of-magnitude gains in overall application performance by making use of many-core GPUs over multi-core CPUs and this fact is largely independent of the specific hardware architecture and vendor. We also observe that a single high-end GPU can match the performance of a small-sized, message-passing based CPU cluster.

Micromagnetic simulations were performed to determine the effects of three anisotropy sources on the orientation ratio (OR) in circumferentially-textured longitudinal recording media. Models of the Co c-axis distribution, disruption of the magnetic coupling due to the texture lines, and stress anisotropy were used to generate hysteresis loops in both parallel and perpendicular directions. Parameters were obtained from experimental measurements. Of these three anisotropy sources, a preferential alignment of the Co c-axis along the grooves produces the largest OR; disruption of the magnetic coupling yields a smaller OR value, but leads to the perpendicular loop closing outside the parallel loop. Although the stress anisotropy increases the coercivity in both directions, the OR is the smallest. A combination of these three anisotropy sources, as well as a weak intergranular exchange, leads to agreement with the experimental measurement of OR.

Jacobson and Sotiriou showed that rotating black holes could be spun-up past the extremal limit by the capture of non-spinning test bodies, if one neglects radiative and self-force effects. This would represent a violation of the Cosmic Censorship Conjecture in four-dimensional, asymptotically flat spacetimes. We show that for some of the trajectories giving rise to naked singularities, radiative effects can be neglected. However, for these orbits the conservative self-force is important, and seems to have the right sign to prevent the formation of naked singularities., 4 pages, 1 table. Phys. Rev. Lett. in press. Substantially improved version, showing that the conservative self-force's sign is the right one to prevent the formation of naked singularities for all orbits

Three interrelated questions concerning Kerr spacetime late-time scalar-field tails are considered numerically, specifically the evolutions of generic and non-generic initial data sets, the excitation of "up" modes, and the resolution of an apparent paradox related to the superposition principle. We propose to generalize the Barack-Ori formula for the decay rate of any tail multipole given a generic initial data set, to the contribution of any initial multipole mode. Our proposal leads to a much simpler expression for the late-time power law index. Specifically, we propose that the late-time decay rate of the $Y_{\ell m}$ spherical harmonic multipole moment because of an initial $Y_{\ell' m}$ multipole is independent of the azimuthal number $m$, and is given by $t^{-n}$, where $n=\ell'+\ell+1$ for $\ell, Comment: 12 pages, 13 figures, 4 tables. Substantially revised manuscript

Spectacular breakthroughs in numerical relativity now make it possible to compute spacetime dynamics in almost complete generality, allowing us to model the coalescence and merger of binary black holes with essentially no approximations. The primary limitation of these calculations is now computational. In particular, it is difficult to model systems with large mass ratio and large spins, since one must accurately resolve the multiple lengthscales which play a role in such systems. Perturbation theory can play an important role in extending the reach of computational modeling for binary systems. In this paper, we present first results of a code which allows us to model the gravitational waves generated by the inspiral, merger, and ringdown of a binary system in which one member of the binary is much more massive than the other. This allows us to accurately calibrate binary dynamics in the large mass ratio regime. We focus in this analysis on the recoil imparted to the merged remnant by these waves. We closely examine the “antikick,” an anti-phase cancellation of the recoil arising from the plunge and ringdown waves, described in detail by Schnittman et al. We find that, for orbits aligned with the black hole spin, the antikick grows as a function of spin. The total recoil is smallest for prograde coalescence into a rapidly rotating black hole, and largest for retrograde coalescence. Amusingly, this completely reverses the predicted trend for kick versus spin from analyses that only include inspiral information., National Aeronautics and Space Administration (Grant No. NNG05G105G), National Science Foundation (Grant No. PHY-0449884)

The thermonuclear explosion of a C/O white dwarf as a Type Ia supernova (SN Ia) generates a kinetic energy comparable to that released by a massive star during a SN II event. Current observations and theoretical models have established that SNe Ia are asymmetric, and therefore--like SNe II--potential sources of gravitational wave (GW) radiation. We perform the first detailed calculations of the GW emission for a SN Ia of any type within the single-degenerate channel. The gravitationally-confined detonation (GCD) mechanism predicts a strongly-polarized GW burst in the frequency band around 1 Hz. Third-generation spaceborne GW observatories currently in planning may be able to detect this predicted signal from SNe Ia at distances up to 1 Mpc. If observable, GWs may offer a direct probe into the first few seconds of the SNe Ia detonation., Comment: 8 pages, 4 figures, Accepted by Physical Review Letters

We present a detailed approach for making use of two new computer hardware architectures-CBEA and CUDA-for accelerating a scientific data-analysis application (Einstein@Home). Our results suggest that both the architectures suit the application quite well and the achievable performance in the same software developmental timeframe is nearly identical.

Background: Historically, minimally to moderately displaced extra-articular scapula fractures have been managed conservatively. It is possible that operative criteria could be met for a given patient if progressive displacement were to occur. We hypothesize that certain displaced scapula fractures progressively displace in early postinjury period. Methods: A consecutive series of 49 patients with operatively managed extra-articular scapula fractures was evaluated to identify patients initially managed nonoperatively and later operatively because of progressive displacement. Three examiners then independently analyzed radiographs to measure the displacement between injury films and the films used to determine operative indications. A standard method for radiographic measurement of deformity was developed and was used to determine the degree of deformity at injury and at follow-up time when operative care was decided. Results: Eight patients met inclusion criteria. All sustained a specific extra-articular transverse fracture pattern Arbeitsgemeinschaft fur Osteosynthefragen/ Orthopaedic Trauma Association (AO/OTA) Type A3, Ada-Miller Type IIC). Mean time interval between injury and repeat radiographs was 11.3 (range, 9—15) days. All patients displayed progressive displacement in at least one of the four measured parameters (medial/lateral displacement, angulation, translation, and glenopolar angle), according to the three independent examiners. Predominantly "good" inter- and intraobserver scores were achieved. Conclusions: Certain extra-articular scapula fractures may displace in postinjury period. We recommend close monitoring of conservatively treated fractures to screen for progressive displacement.

Hardware accelerators (such as the Cell Broadband Engine) have recently received a significant amount of attention from the computational science community because they can provide significant gains in the overall performance of many numerical simulations at a low cost. However, such accelerators usually employ a rather unfamiliar and specialized programming model that often requires advanced knowledge of their hardware design. In this article, we demonstrate an alternate and simpler approach towards managing the main complexities in the programming of the Cell processor, called software caching. We apply this technique to a numerical relativity application: a time-domain, finite-difference Kerr black hole perturbation evolver, and present the performance results. We obtain gains in the overall performance of generic simulations that are close to the theoretical maximum that can be obtained through our parallelization approach., 5 pages, 2 figures; Accepted for publication in the International Journal of Modeling, Simulation, and Scientific Computing (IJMSSC)

Gravitational waveforms and fluxes from extreme mass--ratio inspirals can be computed using time--domain methods with accuracy that is fast approaching that of frequency--domain methods. We study in detail the computational efficiency of these methods for equatorial orbits of fast spinning Kerr black holes, and find the number of modes needed in either method --as functions of the orbital parameters-- in order to achieve a desired accuracy level. We then estimate the total computation time and argue that for high eccentricity orbits the time--domain approach is more efficient computationally. We suggest that in practice low--$m$ modes are computed using the frequency--domain approach, and high--$m$ modes are computed using the time--domain approach, where $m$ is the azimuthal mode number., Comment: 19 figures, 6 tables

This is the second in a series of papers whose aim is to generate ``adiabatic'' gravitational waveforms from the inspiral of stellar-mass compact objects into massive black holes. In earlier work, we presented an accurate (2+1)D finite-difference time-domain code to solve the Teukolsky equation, which evolves curvature perturbations near rotating (Kerr) black holes. The key new ingredient there was a simple but accurate model of the singular source term based on a discrete representation of the Dirac-delta function and its derivatives. Our earlier work was intended as a proof of concept, using simple circular, equatorial geodesic orbits as a testbed. Such a source is effectively static, in that the smaller body remains at the same coordinate radius and orbital inclination over an orbit. (It of course moves through axial angle, but we separate that degree of freedom from the problem. Our numerical grid has only radial, polar, and time coordinates.) We now extend the time-domain code so that it can accommodate dynamic sources that move on a variety of physically interesting world lines. We validate the code with extensive comparison to frequency-domain waveforms for cases in which the source moves along generic (inclined and eccentric) bound geodesic orbits. We also demonstrate the ability of the time-domain code to accommodate sources moving on interesting non-geodesic worldlines. We do this by computing the waveform produced by a test mass following a ``kludged'' inspiral trajectory, made of bound geodesic segments driven toward merger by an approximate radiation loss formula., Comment: 14 pages, 5 figures. Accepted by Phys. Rev. D

In this paper, we propose to employ two optimizations - multi-hop path splitting and multi-pathing - to improve the performance of data transfers over shared public networks. We present a path determination algorithm which integrates the aforesaid optimizations in order to improve the performance of single file transfers. Finally, we develop a file transfer scheduling algorithm based on this framework, and evaluate its effectiveness on a wide-area testbed.

Many scientific applications need to stage large volumes of files from one set of machines to another set of machines in a wide-area network. Efficient execution of such data transfers needs to take into account the heterogeneous nature of the environment and dynamic availability of shared resources. This paper proposes an algorithm that dynamically schedules a batch of data transfer requests with the goal of minimizing the overall transfer time. The proposed algorithm performs simultaneous transfer of chunks of files from multiple file replicas, if the replicas exist. Adaptive replica selection is employed to transfer different chunks of the same file by taking dynamically changing network band- widths into account. We utilize GridFTP as the underlying mechanism for data transfers. The algorithm makes use of information from past GridFTP transfers to estimate network bandwidths and resource availability. The efficiency of the algorithm is evaluated on a wide-area testbed.

The inhomogeneous Zerilli equation is solved in time-domain numerically with the Chebyshev spectral collocation method to investigate a radial-infall of the point particle towards a Schwarzschild black hole. Singular source terms due to the point particle appear in the equation in the form of the Dirac $\delta$-function and its derivative. For the approximation of singular source terms, we use the direct derivative projection method without any regularization. The gravitational waveforms are evaluated as a function of time. We compare the results of the spectral collocation method with those of the explicit second-order central-difference method. The numerical results show that the spectral collocation approximation with the direct projection method is accurate and converges rapidly when compared with the finite-difference method., Comment: Accepted for publication in International Journal of Modern Physics C (IJMPC)

We revisit the problem of the emission of gravitational waves from a test mass orbiting and thus perturbing a Kerr black hole. The source term of the Teukolsky perturbation equation contains a Dirac delta function which represents a point particle. We present a technique to effectively model the delta function and its derivatives using as few as four points on a numerical grid. The source term is then incorporated into a code that evolves the Teukolsky equation in the time domain as a (2+1) dimensional PDE. The waveforms and energy fluxes are extracted far from the black hole. Our comparisons with earlier work show an order of magnitude gain in performance (speed) and numerical errors less than 1% for a large fraction of parameter space. As a first application of this code, we analyze the effect of finite extraction radius on the energy fluxes. This paper is the first in a series whose goal is to develop adiabatic waveforms describing the inspiral of a small compact body into a massive Kerr black hole., Comment: 21 pages, 6 figures, accepted by PRD. This version removes the appendix; that content will be subsumed into future work

A general class of loop quantizations for anisotropic models is introduced and discussed, which enhances loop quantum cosmology by relevant features seen in inhomogeneous situations. The main new effect is an underlying lattice which is being refined during dynamical changes of the volume. In general, this leads to a new feature of dynamical difference equations which may not have constant step-size, posing new mathematical problems. It is discussed how such models can be evaluated and what lattice refinements imply for semiclassical behavior. Two detailed examples illustrate that stability conditions can put strong constraints on suitable refinement models, even in the absence of a fundamental Hamiltonian which defines changes of the underlying lattice. Thus, a large class of consistency tests of loop quantum gravity becomes available. In this context, it will also be seen that quantum corrections due to inverse powers of metric components in a constraint are much larger than they appeared recently in more special treatments of isotropic, free scalar models where they were artificially suppressed., 24 pages

Oxford unicompartmental knee replacement surgery (Biomet Orthopedics, Inc, Warsaw, Ind) provides excellent long-term results according to numerous published series, with 10-year survivorship ranging from 91% to 100% and 15- year survivorship of 93%. Few knee prostheses can rival these results. Most of these cohorts included patients with anteromedial- or medial-specific disease, although some cohorts included patients with lateral-specific disease. Also, most cohorts were performed in patients with a mean age of60 years, with a wide range of ages including patients in their 30s to 90s. Almost all of the arthroplasties were performed in patients with osteoarthritis, and some were performed in patients with avascular necrosis.

Children with Hurler syndrome (mucopolysaccharidosis type IH (MPSIH)) have skeletal, joint and soft tissue abnormalities that may persist or progress after hematopoietic stem cell transplantation (HSCT). We report our single center experience with development of carpal tunnel syndrome (CTS) in 43 children with MPSIH after HSCT. Twenty-three children (59%) developed CTS following HSCT; 19 of the 39 children with enzyme activity in the normal or heterozygous range developed CTS (49%), whereas all four children with low heterozygous or absent enzyme activity developed CTS after HSCT. Fourteen of 19 related donor marrow recipients, eight of 19 of those receiving an unrelated donor graft and one of five unrelated cord blood recipients developed CTS. The mean age at surgical release was 4.8 years. With each year increase in age at HSCT, there was a 55% increased risk. Age and enzyme activity after HSCT were significant factors in the development of CTS. Transplantation by 2 years of age reduced the risk of developing CTS by 46%; higher enzyme activity led to a 78% reduction in the risk of developing CTS. However, children transplanted for MPSIH remain at risk for the development of CTS, and should be monitored on an ongoing basis by nerve conduction velocity testing.