2,593 research outputs found
Einstein Gravity on a Brane in 5D Non-compact Flat Spacetime -DGP model revisited-
We revisit the 5D gravity model by Dvali, Gabadadze, and Porrati (DGP).
Within their framework it was shown that even in 5D non-compact Minkowski space
, the Newtonian gravity can emerge on a brane at short distances by
introducing a brane-localized 4D Einstein-Hilbert term
in the action. Based on this idea,
we construct simple setups in which graviton standing waves can arise, and we
introduce brane-localized derivative terms as a correction to
. We show that the gravity potential
of brane matter becomes at {\it long} distances, because the
brane-localized derivative terms allow only a smooth graviton wave function
near the brane. Since the bulk gravity coupling may be arbitrarily small,
strongly interacting modes from the 5D graviton do not appear. We note that the
brane metric utilized to construct
can be relatively different from the bulk metric by a conformal factor, and
show that the graviton tensor structure that the 4D Einstein gravity predicts
are reproduced in DGP type models.Comment: 1+12 pages, no figure, to appear in JHE
Reduction of critical temperatures in pure and thoriated UBe13 by columnar defects
We investigate the influence of columnar defects on the superconducting
transition temperatures of pure and thoriated UBe13. The defects cause all the
transitions to widen and to drop slightly in temperature. Quantitatively, the
single UBe13 transition resembles the lower transition in a sample with 3%
thorium more closely than the upper thoriated transition.Comment: 3 pages, 1 figure. To be presented at M2S-HTSC-V
Accelerated Particle Swarm Optimization and Support Vector Machine for Business Optimization and Applications
Business optimization is becoming increasingly important because all business
activities aim to maximize the profit and performance of products and services,
under limited resources and appropriate constraints. Recent developments in
support vector machine and metaheuristics show many advantages of these
techniques. In particular, particle swarm optimization is now widely used in
solving tough optimization problems. In this paper, we use a combination of a
recently developed Accelerated PSO and a nonlinear support vector machine to
form a framework for solving business optimization problems. We first apply the
proposed APSO-SVM to production optimization, and then use it for income
prediction and project scheduling. We also carry out some parametric studies
and discuss the advantages of the proposed metaheuristic SVM.Comment: 12 page
Non-Fermi liquid normal state of the Heavy Fermion superconductor UBe13
Non-Fermi liquid (NFL) behavior in the normal state of the heavy-fermion
superconductor UBe13 is studied by means of low-temperature measurements of the
specific heat, C, and electrical resistivity, \rho, on a high-quality single
crystal in magnetic fields up to 15.5 T. At B=0, unconventional
superconductivity forms at Tc=0.9 K out of an incoherent state, characterized
by a large and strongly temperature dependent \rho(T). In the magnetic field
interval 4 T \leq B \leq 10 T, \rho(T) follows a T^3/2 behavior for Tc(B)\leq T
\leq 1 K, while \rho is proportional to T at higher temperatures. Corresponding
Non-Fermi liquid behavior is observed in C/T as well and hints at a nearby
antiferromagnetic (AF) quantum critical point (QCP) covered by the
superconducting state. We speculate that the suppression of short-range AF
correlations observed by thermal expansion and specific heat measurements below
T_L \simeq 0.7 K (B=0) yields a field-induced QCP, T_L \to 0, at B=4.5 T.Comment: Presented at the M2S-2003 conference in Rio / Brazi
Ratios of Elastic Scattering of Pions from 3H and 3He
We have measured the elastic-scattering ratios of normalized yields for
charged pions from 3H and 3He in the backward hemisphere. At 180 MeV, we
completed the angular distribution begun with our earlier measurements, adding
six data points in the angular range of 119 deg to 169 deg in the pi-nucleus
center of mass. We also measured an excitation function with data points at
142, 180, 220, and 256 MeV incident pion energy at the largest achievable angle
for each energy between 160 deg and 170 deg in the pi-nucleus center of mass.
This excitation function corresponds to the energies of our forward-hemisphere
studies. The data, taken as a whole, show an apparent role reversal of the two
charge-symmetric ratios r1 and r2 in the backward hemisphere. Also, for data >
100 deg we observe a strong dependence on the four-momentum transfer squared
(-t) for all of the ratios regardless of pion energy or scattering angle, and
we find that the superratio R data match very well with calculations based on
the forward-hemisphere data that predicts the value of the difference between
the even-nucleon radii of 3H and 3He. Comparisons are also made with recent
calculations incorporating different wave functions and double scattering
models.Comment: RevTex 8pages, 12 figure file
Golgi Outpost Synthesis Impaired by Toxic Polyglutamine Proteins Contributes to Dendritic Pathology in Neurons
Dendrite aberration is a common feature of neurodegenerative diseases caused by protein toxicity, but the underlying mechanisms remain largely elusive. Here, we show that nuclear polyglutamine (polyQ) toxicity resulted in defective terminal dendrite elongation accompanied by a loss of Golgi outposts (GOPs) and a decreased supply of plasma membrane (PM) in Drosophila class IV dendritic arborization (da) (C4 da) neurons. mRNA sequencing revealed that genes downregulated by polyQ proteins included many secretory pathway-related genes, including COPII genes regulating GOP synthesis. Transcription factor enrichment analysis identified CREB3L1/CrebA, which regulates COPII gene expression. CrebA overexpression in C4 da neurons restores the dysregulation of COPII genes, GOP synthesis, and PM supply. Chromatin immunoprecipitation (ChIP)-PCR revealed that CrebA expression is regulated by CREB-binding protein (CBP), which is sequestered by polyQ proteins. Furthermore, co-overexpression of CrebA and Rac1 synergistically restores the polyQ-induced dendrite pathology. Collectively, our results suggest that GOPs impaired by polyQ proteins contribute to dendrite pathology through the CBP-CrebA-COPII pathway. ? 2017 The Author(s)113Ysciescopu
Elastic scattering and breakup of 17^F at 10 MeV/nucleon
Angular distributions of fluorine and oxygen produced from 170 MeV 17^F
incident on 208^Pb were measured. The elastic scattering data are in good
agreement with optical model calculations using a double-folding potential and
parameters similar to those obtained from 16^O+208^Pb. A large yield of oxygen
was observed near \theta_lab=36 deg. It is reproduced fairly well by a
calculation of the (17^F,16^O) breakup, which is dominated by one-proton
stripping reactions. The discrepancy between our previous coincidence
measurement and theoretical predictions was resolved by including core
absorption in the present calculation.Comment: 9 pages, 5 figure
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