1,503 research outputs found
A study of point discharge current observations in the thunderstorm environment at a tropical station during the year 1987 and 1988
The results of the measurements of point discharge current observations at Pune, India, during years 1987 and 1988 are presented by categorizing and studying their number of spells, polar current average durations, and current magnitudes in day-time and night-time conditions. While the results showed that the thunderstorm activity occupies far more day-time than the night-time the level of current magnitudes remains nearly the same in the two categories
Axial Anomaly and Transition Form Factors
We investigate the properties of the amplitude induced by the anomaly. In a
relatively high energy region those amplitudes are constructed by the vector
meson poles and the anomaly terms, in which the anomaly terms can be
essentially evaluated by the triangle quark graph. We pay our attention to the
anomaly term and make intensive analysis of the existing experimental data,
i.e., the electromagnetic and transition form factors. Our
result shows that it is essential to use the constituent quark mass instead of
the current quark mass in evaluating the anomaly term from the triangle graph.Comment: LaTeX, 14 pages + 4 figures, (figures are included as uuencoded
files), KUNS-1210 HE(TH) 93/0
Wess-Zumino Terms in Supersymmetric Gauge Theories
The Wess-Zumino term is constructed for supersymmetric QCD with two colors
and flavors, and is shown to correctly reproduce the anomalous Ward identities.
Supersymmetric QCD is also shown not to have topologically stable skyrmion
solutions because of baryon flat directions, which allow them to unwind. The
generalization of these results to other supersymmetric theories with quantum
modified constraints is discussed.Comment: 4 pages (revtex
Low-lying even parity meson resonances and spin-flavor symmetry
A study is presented of the wave meson-meson interactions involving
members of the nonet and of the octet. The starting point is an
SU(6) spin-flavor extension of the SU(3) flavor Weinberg-Tomozawa Lagrangian.
SU(6) symmetry breaking terms are then included to account for the physical
meson masses and decay constants, while preserving partial conservation of the
axial current in the light pseudoscalar sector. Next, the matrix amplitudes
are obtained by solving the Bethe Salpeter equation in coupled-channel with the
kernel built from the above interactions. The poles found on the first and
second Riemann sheets of the amplitudes are identified with their possible
Particle Data Group (PDG) counterparts. It is shown that most of the low-lying
even parity PDG meson resonances, specially in the and sectors,
can be classified according to multiplets of the spin-flavor symmetry group
SU(6). The , and some resonances cannot be
accommodated within this SU(6) scheme and thus they would be clear candidates
to be glueballs or hybrids. Finally, we predict the existence of five exotic
resonances ( and/or ) with masses in the range 1.4--1.6 GeV,
which would complete the , , and multiplets of
SU(3)SU(2).Comment: 43 pages, 2 figures, 61 tables. Improved discussion of Section II. To
appear in Physical Review
Unitarity and the color confinement
We discuss how confinement property of QCD results in the rational
unitarization scheme and how unitarity saturation leads to appearance of a
hadron liquid phase at very high temperatures.Comment: 10 pages, no figire
Enhanced Nonperturbative Effects in Z Decays to Hadrons
We use soft collinear effective field theory (SCET) to study nonperturbative
strong interaction effects in Z decays to hadronic final states that are
enhanced in corners of phase space. These occur, for example, in the jet energy
distribution for two jet events near E_J=M_Z/2, the thrust distribution near
unity and the jet invariant mass distribution near zero. The extent to which
such nonperturbative effects for different observables are related is
discussed.Comment: 17 pages. Paper reorganized, and more discussion and results include
Deriving the existence of bound states from the X(3872) and Heavy Quark Symmetry
We discuss the possibility and the description of bound states between
and mesons. We argue that the existence of such a bound state can
be deduced from (i) the weakly bound X(3872) state, (ii) certain assumptions
about the short range dynamics of the system and (iii) heavy quark
symmetry. From these assumptions the binding energy of the possible
bound states is determined, first in a theory containing only
contact interactions which serves as a straightforward illustration of the
method, and then the effects of including the one pion exchange potential are
discussed. In this latter case three isoscalar states are predicted: a positive
and negative C-parity state with a binding energy of and below threshold respectively, and a positive C-parity
shallow state located almost at the threshold. However,
large uncertainties are generated as a consequence of the corrections
from heavy quark symmetry. Finally, the newly discovered isovector
state can be easily accommodated within the present framework by a minor
modification of the short range dynamics.Comment: 21 pages, 3 figures; a sign error in the potential has been corrected
and new predictions have been compute
Functional outcome of middle third humeral shaft fractures treated with anteromedial plate osteosynthesis through an anterolateral approach
Background: The main aim of treatment of the humeral shaft fractures is to establish union with an acceptable humeral alignment and to restore the patient to pre-injury level of function. Plate osteosynthesis remains the standard of surgical treatment displaced middle third humeral fractures. The most commonly used approaches for treating these fractures are posterior and anterolateral, but these approaches can have iatrogenic radial nerve injury. Our aim is to study the incidence of radial nerve palsy and functional outcome of anterolateral approach with anteromedial plating.Methods: A total of 26 patients in the age group of 21 to 62 years were included in this prospective study, who were treated by anteromedial plating through anterolateral approach for humerus shaft. Functional assessment was done using Rodriguez-Merchan criteria.Results: 26 patients with shaft humerus fracture were included in the study with 19 (73%) patients were less than 40 years age. Most common type of fracture pattern is A3 type and the mean duration of surgical time was 60±10 min for anteromedial plating. The time taken for the fracture union was less than 4 months in the most patients (88%). There was no evidence of iatrogenic radial nerve injury. Functional assessment done using Rodriguez-Merchan criteria showed 84.6% of the patients had good to excellent functional outcome.Conclusions: For treatment of displaced middle third humeral fractures open reduction with anteromedial plating through anterolateral approach is surgically safer and gives better functional outcome.
Diquark-Antidiquarks with Hidden or Open Charm and the Nature of X(3872)
Heavy-light diquarks can be the building blocks of a rich spectrum of states
which can accommodate some of the newly observed charmonium-like resonances not
fitting a pure c-cbar assignment. We examine this possibility for hidden and
open charm diquark-antidiquark states deducing spectra from constituent quark
masses and spin-spin interactions. Taking the X(3872) as input we predict the
existence of a 2++ state that can be associated to the X(3940) observed by
Belle and re-examine the state claimed by SELEX, X(2632). The possible
assignment of the previously discovered states D_s(2317) and D_s(2457) is
discussed. We predict X(3872) to be made of two components with a mass
difference related to (m_u-m_d) and discuss the production of X(3872) and of
its charged partner X^(+-) in the weak decays of B^(+,0).Comment: 11 pages, 2 figures, revtex, minor typos correcte
Dynamic changes in synaptic plasticity genes in ipsilateral and contralateral inferior colliculus following unilateral noise-induced hearing loss
Unilateral noise-induced hearing loss reduces the input to the central auditory pathway disrupting the excitatory and inhibitory inputs to the inferior colliculus (IC), an important binaural processing center. Little is known about the compensatory synaptic changes that occur in the IC as a consequence of unilateral noise-induced hearing loss. To address this issue, Sprague–Dawley rats underwent unilateral noise exposure resulting in severe unilateral hearing loss. IC tissues from the contralateral and ipsilateral IC were evaluated for acute (2-d) and chronic (28-d) changes in the expression of 84 synaptic plasticity genes on a PCR array. Arc and Egr1 genes were further visualized by in situ hybridization to validate the PCR results. None of the genes were upregulated, but many were downregulated post-exposure. At 2-d post-exposure, more than 75% of the genes were significantly downregulated in the contralateral IC, while only two were downregulated in the ipsilateral IC. Many of the downregulated genes were related to long-term depression, long-term potentiation, cell adhesion, immediate early genes, neural receptors and postsynaptic density. At 28-d post-exposure, the gene expression pattern was reversed with more than 85% of genes in the ipsilateral IC now downregulated. Most genes previously downregulated in the contralateral IC 2-d post-exposure had recovered; less than 15% remained downregulated. These time-dependent, asymmetric changes in synaptic plasticity gene expression could shed new light on the perceptual deficits associated with unilateral hearing loss and the dynamic structural and functional changes that occur in the IC days and months following unilateral noise-induced hearing loss
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