1,118 research outputs found
The One-Loop Five-Graviton Scattering Amplitude and Its Low-Energy Limit
A covariant path integral calculation of the even spin structure contribution
to the one-loop N-graviton scattering amplitude in the type-II superstring
theory is presented. The apparent divergence of the amplitude is resolved
by separating it into twelve independent terms corresponding to different
orders of inserting the graviton vertex operators. Each term is well defined in
an appropriate kinematic region and can be analytically continued to physical
regions where it develops branch cuts required by unitarity. The zero-slope
limit of the amplitude is performed, and the Feynman diagram content of
the low-energy field theory is examined. Both one-particle irreducible (1PI)
and one-particle redicible (1PR) graphs with massless internal states are
generated in this limit. One set of 1PI graphs has the same divergent
dependence on the cut-off as that found in the four-graviton case, and it is
proved that such graphs exist for all~. The 1PR graphs are contributed by
the poles in the world-sheet chiral Green functions.Comment: 23 pages, ITP-SB-92-6
Association between oxytocin receptor gene polymorphisms and self-rated 'empathic concern' in schizophrenia
The nonapeptide oxytocin (OXT) and its receptor (OXTR) have been implicated in social cognition, empathy, emotion and stress regulation in humans. Previous studies reported associations between OXT and OXTR genetic polymorphisms and risk for disorders characterized by impaired socio-emotional functioning, such as schizophrenia and autism. Here we investigate the influence of two single nucleotide polymorphisms (SNPs) within the OXTR gene on a measure of socio-emotional functioning in schizophrenic patients. OXTR SNPs that were previously investigated in other studies were genotyped in 145 patients diagnosed with schizophrenia according to DSM-IV and 145 healthy controls matched for age and gender. The Interpersonal Reactivity Index (IRI) was used to assess cognitive ('perspective taking'), affective ('empathic concern') and self-related ('personal distress') dimensions of empathy. No group differences in genotype frequencies were observed. MANCOVA revealed a significant main (F [1,282] = 10.464; pGG) with 'empathic concern'. Within the schizophrenia group, linear regression analysis determined OXTR rs2254298 genotype, PANSS negative and general symptom score, and age of disease onset as being significantly associated with 'empathic concern'. OXTR rs2254298 significantly impacted PANSS general psychopathology scores. No associations were found for OXTR rs53576, IRI 'perspective taking' or 'personal distress' ratings. Our preliminary findings support hypotheses about an involvement of OXTR rs2254298 in emotional empathy in schizophrenic and healthy individuals, warranting independent replication
Overcoming a fast transverse instability by means of octupole-induced tune spread in the Relativistic Heavy Ion Collider
During the Relativistic Heavy Ion Collider commissioning in 2001 a fast transverse instability was observed on the ramp. In general this could be counteracted with increased chromaticity, resulting in Landau damping. However this method could not be applied around transition energy where chromaticities have to change sign. So octupoles were used near transition energy to create transverse Landau damping and avoid the transverse instability, emittance blowup, and beam loss. This paper describes the considerations that led to the present scheme, as well as experimental results
Student Recital: Marvin J. Carlton, Oboe; Wayne L. Montag, Clarinet; July 27, 1975
Hayden AuditoriumSunday EveningJuly 27, 19758:15 p.m
On the number of minimal completely separating systems and antichains in a Boolean lattice
An (n)completely separating system C ((n)CSS) is a collection of blocks of [n] = {1,..., n} such that for all distinct a, b ∈ [n] there are blocks A, B ∈C with a ∈ A \ B and b ∈ B \ A. An (n)CSS is minimal if it contains the minimum possible number of blocks for a CSS on [n]. The number of non-isomorphic minimal (n)CSSs is determined for 11 ≤ n ≤ 35. This also provides an enumeration of a natural class of antichains
In Search of Exoplanets
Using data archives containing radial-velocity and light intensity information for stars, the DePaul Astrophysics Working Group created MATLAB programs to read and analyze the data in hopes of detecting extrasolar planets. The codes were able to successfully create graphs and obtain orbital periods for potential planets which matched published results. Additional tests were then researched to be used in the future as to confirm new planets
An Investigation on Cooling of CZT Co-Planar Grid Detectors
The effect of moderate cooling on CdZnTe semiconductor detectors has been
studied for the COBRA experiment. Improvements in energy resolution and low
energy threshold were observed and quantified as a function of temperature.
Leakage currents are found to contribute typically 5 keV to the widths of
photopeaks.Comment: 14 pages, 9 figures. Accepted for publication in Nuclear Inst. and
Methods in Physics Research,
Facilities for the Energy Frontier of Nuclear Physics
The Relativistic Heavy Ion Collider at BNL has been exploring the energy
frontier of nuclear physics since 2001. Its performance, flexibility and
continued innovative upgrading can sustain its physics output for years to
come. Now, the Large Hadron Collider at CERN is about to extend the frontier
energy of laboratory nuclear collisions by more than an order of magnitude. In
the coming years, its physics reach will evolve towards still higher energy,
luminosity and varying collision species, within performance bounds set by
accelerator technology and by nuclear physics itself. Complementary high-energy
facilities will include fixed-target collisions at the CERN SPS, the FAIR
complex at GSI and possible electron-ion colliders based on CEBAF at JLAB, RHIC
at BNL or the LHC at CERN.Comment: Invited talk at the International Nuclear Physics Conference,
Vancouver, Canada, 4-9 July 2010, to be published in Journal of Physics:
Conference Series. http://inpc2010.triumf.ca
Radiation-Induced Leiomyosarcoma: Does Antimetabolite Chemotherapy Contribute? A Report of Three Cases
Purpose: Radiation therapy in low and high doses is known to be associated with the occurrence of late secondary sarcomas.
The addition of chemotherapy has not been clearly demonstrated as a contributing factor. We describe three patients with
radiation-associated leiomyosarcoma who had also received antimetabolite chemotherapy
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