6,325 research outputs found

    Changes in hospitals' credentialing requirements for board certification from 2005 to 2010

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98213/1/jhm2033.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/98213/2/jhm23033-sup-0001-suppinfo.pd

    Non-Abelian Chern-Simons models with discrete gauge groups on a lattice

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    We construct the local Hamiltonian description of the Chern-Simons theory with discrete non-Abelian gauge group on a lattice. We show that the theory is fully determined by the phase factors associated with gauge transformations and classify all possible non-equivalent phase factors. We also construct the gauge invariant electric field operators that move fluxons around and create/anihilate them. We compute the resulting braiding properties of the fluxons. We apply our general results to the simplest class of non-Abelian groups, dihedral groups D_n.Comment: 16 pages, 7 figure

    Rare first rib pseudoarthrosis with thoracic outlet syndrome in pediatric gymnast: A case report

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    Background: This case study evaluates the diagnosis and treatment of a 12 year old Caucasian male gymnast who had several diagnoses including an isolated first rib fracture, resultant pseudoarthrosis of the first rib, and the development of symptomatic thoracic outlet syndrome. We discuss the causes, prevalence, and suggestions for prompt diagnosis and treatment of these conditions in pediatric patients. Although all three conditions are rare in a child, this case highlights the importance of having a high clinical index of suspicion in recurrent pain in pre-pubertal athletes. Case presentation: A 10 year old Caucasian male presented with a two to three month history of worsening left shoulder pain. He was a competitive gymnast who practiced approximately ten hours per week. His shoulder pain was accompanied by a tic type movement consisting of hyperextension of the left shoulder multiple times per day. The patient was seen by a pediatric orthopedic surgeon who diagnosed the patient with overuse syndrome and prescribed physical therapy. Within one to two months, the patient\u27s shoulder pain and tightness returned. For two years, the patient continued the cycle multiple times of two to three months of physical therapy two to three times a week, relative rest, then returned to activity. He continued to be diagnosed with “overuse syndrome”. At the age of 12, the patient\u27s mother noticed atrophy to the left upper scapula region and vague weakness of the left upper extremity. Cervical MRI showed “unusual nodular mass at the apex of the left hemithorax involving the antero-lateral aspect of the left first rib.” 3D reconstructed CT images were done showing first rib pseudoarthrosis as well as demonstrating a non-displaced fracture through the left second rib. The patient underwent a left first rib resection without complication. He recovered well post operatively; the pain, “tic”, and atrophy drastically improved, and he returned to his baseline activity level. Conclusions: Children involved in high impact sports are subject to fractures due to the muscles pulling on the bone. Our patient not only had a first rib fracture, but also had incorrect healing of the fracture leading to pseudoarthrosis and eventual thoracic outlet syndrome. With the continued failure of conservative treatment for pain, more imaging studies should be ordered to evaluate for any missed pathologies. Removal of the first rib is a definitive treatment and should be considered if the patient’s thoracic outlet syndrome symptoms do not improve with conservative measures such as lifestyle modifications or physical therapy

    Normal Bundles, Pfaffians and Anomalies

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    We deal with the problem of diffeomorphism anomaly in theories with branes. In particular we thoroughly analyze the problem of the residual chiral anomaly of a five-brane immersed in M-theory, paying attention to its global formulation in the five-brane world-volume. We conclude that the anomaly can be canceled by a {\it local} counterterm in the five-brane world-volume.Comment: 17 pages, Latex, sign convention changed, typos correcte

    On the Quantum Invariant for the Brieskorn Homology Spheres

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    We study an exact asymptotic behavior of the Witten-Reshetikhin-Turaev invariant for the Brieskorn homology spheres ÎŁ(p1,p2,p3)\Sigma(p_1,p_2,p_3) by use of properties of the modular form following a method proposed by Lawrence and Zagier. Key observation is that the invariant coincides with a limiting value of the Eichler integral of the modular form with weight 3/2. We show that the Casson invariant is related to the number of the Eichler integrals which do not vanish in a limit τ→N∈Z\tau\to N \in \mathbb{Z}. Correspondingly there is a one-to-one correspondence between the non-vanishing Eichler integrals and the irreducible representation of the fundamental group, and the Chern-Simons invariant is given from the Eichler integral in this limit. It is also shown that the Ohtsuki invariant follows from a nearly modular property of the Eichler integral, and we give an explicit form in terms of the L-function.Comment: 26 pages, 2 figure

    Renormalization Ambiguities in Chern-Simons Theory

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    We introduce a new family of gauge invariant regularizations of Chern-Simons theories which generate one-loop renormalizations of the coupling constant of the form k→k+2scvk\to k+2 s c_v where ss can take any arbitrary integer value. In the particular case s=0s=0 we get an explicit example of a gauge invariant regularization which does not generate radiative corrections to the bare coupling constant. This ambiguity in the radiative corrections to kk is reminiscent of the Coste-L\"uscher results for the parity anomaly in (2+1) fermionic effective actions.Comment: 10 pages, harvmac, no changes, 1 Postscript figure (now included

    Tunneling and Quantum Noise in 1-D Luttinger Liquids

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    We study non-equilibrium noise in the transmission current through barriers in 1-D Luttinger liquids and in the tunneling current between edges of fractional quantum Hall liquids. The distribution of tunneling events through narrow barriers can be described by a Coulomb gas lying in the time axis along a Keldysh (or non-equilibrium) contour. The charges tend to reorganize as a dipole gas, which we use to describe the tunneling statistics. Intra-dipole correlations contribute to the high-frequency ``Josephson'' noise, which has an algebraic singularity at ω=e∗V/ℏ\omega=e^*V/\hbar, whereas inter-dipole correlations are responsible for the low-frequency noise. Inter-dipole interactions give a 1/t21/t^2 correlation between the tunneling events that results in a âˆŁÏ‰âˆŁ|\omega| singularity in the noise spectrum. We present a diagrammatic technique to calculate the correlations in perturbation theory, and show that contributions from terms of order higher than the dipole-dipole interaction should only affect the strength of the âˆŁÏ‰âˆŁ|\omega| singularity, but its form should remain âˆŒâˆŁÏ‰âˆŁ\sim |\omega| to all orders in perturbation theory.Comment: RevTex, 9 figures available upon request, cond-mat/yymmnn

    Classifying A-field and B-field configurations in the presence of D-branes

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    We "solve" the Freed-Witten anomaly equation, i.e., we find a geometrical classification of the B-field and A-field configurations in the presence of D-branes that are anomaly-free. The mathematical setting being provided by the geometry of gerbes, we find that the allowed configurations are jointly described by a coset of a certain hypercohomology group. We then describe in detail various cases that arise according to such classification. As is well-known, only under suitable hypotheses the A-field turns out to be a connection on a canonical gauge bundle. However, even in these cases, there is a residual freedom in the choice of the bundle, naturally arising from the hypercohomological description. For a B-field which is flat on a D-brane, fractional or irrational charges of subbranes naturally appear; for a suitable gauge choice, they can be seen as arising from "gauge bundles with not integral Chern class": we give a precise geometric interpretation of these objects.Comment: 28 pages, no figure
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