2,275 research outputs found

    Novel Edge States in Self-Dual Gravity

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    In contrast to the Einstein-Hilbert action, the action for self-dual gravity contains vierbeins. They are eleminated at the level of observables by an SL(2,C)SL(2,\mathbb{C}) gauge condition implied by the action. We argue that despite this condition, new "edge" or superselected state vectors corresponding to maps of the spheres S∞2S^2_{\infty} at infinity to SL(2,C)SL(2, \mathbb{C}) arise. They are characterised by new quantum numbers and they lead to mixed states. For black holes, they arise both at the horizon and the spatial infinity and may be relevant for the black hole information paradox. Similar comments can be made about the Einstein-Palatini action which uses vierbeins.Comment: 15 pages, reference added, some minor notational changes - no changes in conclusio

    Demographic study of craniosynostosis patients in mid-Missouri

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    Craniosynostosis is a congenital defect in which one or more of the cranial sutures close prematurely, affecting 1 in 2000 to 2500 live births worldwide. Historically, sagittal craniosynostosis has been reported to be the most common form of single-suture craniosynostosis. Our previous retrospective review of craniosynostosis at our institution reported that the incidence of metopic craniosynostosis in mid-Missouri is significantly greater than that of sagittal craniosynostosis, 65% versus 13% (Table 1). Our current aim is to further investigate the demographic characteristics of our institution's craniosynostosis population

    Do Patients with Craniosynostosis Have an Increased Incidence of Auditory Neuropathy as Newborns?

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    Neuroscience - Vision & Functional Brain Imaging Poster SessionOBJECTIVE: To investigate the incidence of auditory neuropathy, abnormal auditory brainstem response (ABR) with normal otoacoustic emissions, in newborn patients with craniosynostosis as compared to published standards. DESIGN: A retrospective review of consecutive patients with single or multiple-suture craniosynostosis who were seen between 2002 and 2009. Patients identified by the diagnostic code of craniosynostosis were divided into groups based on suture involvement. The newborn ABR screening and, if patients were referred, diagnosis from audiologic diagnostic testing were obtained from the Missouri Department of Health. Institutional review board approval was obtained. PATIENTS: One hundred and thirty-five patients were identified. Seventy-two were excluded; 3 were listed as “missed” and 69 were not born in-state. The 63 patients included in the study were grouped by involved sutures: 2 left coronal, 7 right coronal, 2 nonsyndromic bicoronal, 3 syndromic bicoronal, 13 sagittal, 17 operative metopic, 15 nonoperative metopic, 1 pansynostosis, and 3 multiple-suture. MAIN OUTCOME MEASURES: The newborn screening results for each patient were recorded as well as the diagnosis from audiologic diagnostics if the patient was referred. RESULTS: Of the 63 patients, 94% (59/63) passed their ABR screening. Four were referred for diagnostic exam in both ears. Of those, one had a normal exam (right coronal) and three did not have diagnostic exams on file (right coronal, bicoronal syndromic and bicoronal non-syndromic). CONCLUSIONS: According to the Centers for Disease Control, 1.8 percent of newborns failed their ABR screening in 2007. Of those, 37% were found to have normal hearing on diagnostic exam. Although our study was inconclusive due to inadequate state records, it does demonstrate an increased incidence in abnormal ABR's in patients with coronal craniosynostosis. This is consistent with a recent publication that demonstrated higher incidence of abnormal ABR's in syndromic coronal craniosynostosis. If auditory abnormalities are present at birth, as our study suggests, the etiology would be unrelated to increased intracranial pressures

    Curvature condensation and bifurcation in an elastic shell

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    We study the formation and evolution of localized geometrical defects in an indented cylindrical elastic shell using a combination of experiment and numerical simulation. We find that as a symmetric localized indentation on a semi-cylindrical shell increases, there is a transition from a global mode of deformation to a localized one which leads to the condensation of curvature along a symmetric parabolic crease. This process introduces a soft mode in the system, converting a load-bearing structure into a hinged, kinematic mechanism. Further indentation leads to twinning wherein the parabolic crease bifurcates into two creases that move apart on either side of the line of symmetry. A qualitative theory captures the main features of the phenomena and leads to sharper questions about the nucleation of these defects.Comment: 4 pages, 5 figures, submitted to Physical Review Letter

    Induced Magnetic moments in three-dimensional gauge theories with external magnetic fields

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    We study the appearance of induced parity-violating magnetic moment, in the presence of external magnetic fields, for even-number of fermion species coupled to dynamical fields in three dimensions. Specifically, we use a SU(2)xU(1) gauge model for dynamical gauge symmetry breaking, which is also proposed recently as a field theoretical model for high-temperature superconductors. By decomposing the fermionic degrees of freedom in terms of Landau levels, we show that, in the effective theory with the lowest Landau levels, a parity-violating magnetic moment interaction is induced by the higher Landau levels when the fermions are massive. The possible relevance of this result for a recently observed phenomenon in high-temperature superconductors is also discussed.Comment: 15 pages revtex, one figure incorporated, References added no other change

    The Measurement Bench for the LHC Spool Corrector Magnets in Industry

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    The LHC accelerator will be equipped with more than 3500 superconducting spool corrector magnets. CERN has awarded the contract for the series production and testing of these corrector magnets to industry. Magnetic field measurements are done at the factory. Dedicated magnetic measurement benches have been built to test these corrector magnets in the resistive state at room temperature. The benches allow to measure the strength of the main field, normal and skew harmonics, the magnetic axis position and orientation of the main field with respect to the mechanical reference points of the magnet. This paper presents the objectives, a description and the performances obtained with the benches during first measurements at industry

    Maximum Angle of Stability of a Wet Granular Pile

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    Anyone who has built a sandcastle recognizes that the addition of liquid to granular materials increases their stability. However, measurements of this increased stability often conflict with theory and with each other [1-7]. A friction-based Mohr-Coulomb model has been developed [3,8]. However, it distinguishes between granular friction and inter-particle friction, and uses the former without providing a physical mechanism. Albert, {\em et al.} [2] analyzed the geometric stability of grains on a pile's surface. The frictionless model for dry particles is in excellent agreement with experiment. But, their model for wet grains overestimates stability and predicts no dependence on system size. Using the frictionless model and performing stability analysis within the pile, we reproduce the dependence of the stability angle on system size, particle size, and surface tension observed in our experiments. Additionally, we account for past discrepancies in experimental reports by showing that sidewalls can significantly increase the stability of granular material.Comment: 4 pages, 4 figure

    Vicarious or direct? Testing experiences of interpersonal deviance and employees’ defensive strategies at work

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI linkThe interpersonal deviance (ID) literature has mainly relied upon the conservation of resource (COR) theory that explains the dissemination of stressful cues. While literature concerning resource investment decisions at work exists, how and when individuals enter defensive mode is a relatively less researched area. We investigate the effects of two forms of interpersonal deviant experiences, namely, vicarious ID and direct ID that results in self-serving behavior—a defensive withdrawal. We analyzed two waves of 346 subordinate– supervisor pairs. Multilevel path modeling exhibited an indirect effect from direct ID to self-serving behavior via communion striving. On the other hand, there was no indirect effect of vicarious ID on self-serving behavior via communion striving. The results reveal that direct ID is a crucial factor in explaining defensive strategies at work, whereas the effects of vicarious ID are contingent upon certain boundary conditions. Given that, findings show vicarious ID was positively related to communion striving for employees with low relational identification and high susceptibility to emotional contagion. We offer new insights into ID and COR literature by providing important implications for theory and practice
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