6,151 research outputs found
Changes in hospitals' credentialing requirements for board certification from 2005 to 2010
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
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
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
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
We study an exact asymptotic behavior of the Witten-Reshetikhin-Turaev
invariant for the Brieskorn homology spheres 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 . 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
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 where can take any arbitrary integer value. In
the particular case 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 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
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 , whereas inter-dipole correlations
are responsible for the low-frequency noise. Inter-dipole interactions give a
correlation between the tunneling events that results in a
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 singularity, but its form should remain
to all orders in perturbation theory.Comment: RevTex, 9 figures available upon request, cond-mat/yymmnn
Colored noise in the fractional Hall effect: duality relations and exact results
We study noise in the problem of tunneling between fractional quantum Hall
edge states within a four probe geometry. We explore the implications of the
strong-weak coupling duality symmetry existent in this problem for relating the
various density-density auto-correlations and cross-correlations between the
four terminals. We identify correlations that transform as either ``odd'' or
``anti-symmetric'', or ``even'' or ``symmetric'' quantities under duality. We
show that the low frequency noise is colored, and that the deviations from
white noise are exactly related to the differential conductance. We show
explicitly that the relationship between the slope of the low frequency noise
spectrum and the differential conductance follows from an identity that holds
to {\it all} orders in perturbation theory, supporting the results implied by
the duality symmetry. This generalizes the results of quantum supression of the
finite frequency noise spectrum to Luttinger liquids and fractional statistics
quasiparticles.Comment: 14 pages, 3 figure
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