125 research outputs found
Application of neural networks for optimisation of signalling in road traffic
This article presents a proposal for applying neural networks to control road traffic. The proposed solution makes it possible to determine durations of traffic signals at intersections so that the waiting time for transit is as short as possible. The variability of traffic intensity on all access roads and between analysed intersections was taken into account. The developed concept was compared with a method of determining the durations of lights based on the coefficient of intersection readiness, and the feasibility for practical applications of the method was assessed
Caveolins/caveolae protect adipocytes from fatty acid-mediated lipotoxicity
Mice and humans lacking functional caveolae are dyslipidemic and have reduced fat stores and smaller fat cells. To test the role of caveolins/caveolae in maintaining lipid stores and adipocyte integrity, we compared lipolysis in caveolin-1 (Cav1)-null fat cells to that in cells reconstituted for caveolae by caveolin-1 re-expression. We find that the Cav1-null cells have a modestly enhanced rate of lipolysis and reduced cellular integrity compared with reconstituted cells as determined by the release of lipid metabolites and lactic dehydrogenase, respectively, into the media. There are no apparent differences in the levels of lipolytic enzymes or hormonally stimulated phosphorylation events in the two cell lines. In addition, acute fasting, which dramatically raises circulating fatty acid levels in vivo, causes a significant upregulation of caveolar protein constituents. These results are consistent with the hypothesis that caveolae protect fat cells from the lipotoxic effects of elevated levels fatty acids, which are weak detergents at physiological pH, by virtue of the property of caveolae to form detergentresistant membrane domains
Penrose Limits, Deformed pp-Waves and the String Duals of N=1 Large n Gauge Theory
A certain conformally invariant N=1 supersymmetric SU(n) gauge theory has a
description as an infra-red fixed point obtained by deforming the N=4
supersymmetric Yang-Mills theory by giving a mass to one of its N=1 chiral
multiplets. We study the Penrose limit of the supergravity dual of the large n
limit of this N=1 gauge theory. The limit gives a pp-wave with R-R five-form
flux and both R-R and NS-NS three-form flux. We discover that this new solution
preserves twenty supercharges and that, in the light-cone gauge, string theory
on this background is exactly solvable. Correspondingly, this latter is the
stringy dual of a particular large charge limit of the large n gauge theory. We
are able to identify which operators in the field theory survive the limit to
form the string's ground state and some of the spacetime excitations. The full
string model, which we exhibit, contains a family of non-trivial predictions
for the properties of the gauge theory operators which survive the limit.Comment: 39 pages, Late
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Toward a more rigorous application of margins and uncertainties within the nuclear weapons life cycle : a Sandia perspective.
This paper presents the conceptual framework that is being used to define quantification of margins and uncertainties (QMU) for application in the nuclear weapons (NW) work conducted at Sandia National Laboratories. The conceptual framework addresses the margins and uncertainties throughout the NW life cycle and includes the definition of terms related to QMU and to figures of merit. Potential applications of QMU consist of analyses based on physical data and on modeling and simulation. Appendix A provides general guidelines for addressing cases in which significant and relevant physical data are available for QMU analysis. Appendix B gives the specific guidance that was used to conduct QMU analyses in cycle 12 of the annual assessment process. Appendix C offers general guidelines for addressing cases in which appropriate models are available for use in QMU analysis. Appendix D contains an example that highlights the consequences of different treatments of uncertainty in model-based QMU analyses
Correlation Functions of Operators and Wilson Surfaces in the d=6, (0,2) Theory in the Large N Limit
We compute the two and three-point correlation functions of chiral primary
operators in the large N limit of the (0,2), d=6 superconformal theory. We also
consider the operator product expansion of Wilson surfaces in the (0,2) theory
and compute the OPE coefficients of the chiral primary operators at large N
from the correlation functions of surfaces.Comment: 34 pages, using utarticle.cls (included), array.sty, amsmath.sty,
amsfonts.sty, latexsym.sty, epsfig. Bibtex style: utphys.bst (.bbl file
included
Thermal quenches in N=2* plasmas
We exploit gauge/gravity duality to study `thermal quenches' in a plasma of
the strongly coupled N=2* gauge theory. Specifically, we consider the response
of an initial thermal equilibrium state of the theory under variations of the
bosonic or fermionic mass, to leading order in m/T<<1. When the masses are made
to vary in time, novel new counterterms must be introduced to renormalize the
boundary theory. We consider transitions the conformal super-Yang-Mills theory
to the mass deformed gauge theory and also the reverse transitions. By
construction, these transitions are controlled by a characteristic time scale
\calt and we show how the response of the system depends on the ratio of this
time scale to the thermal time scale 1/T. The response shows interesting
scaling behaviour both in the limit of fast quenches with T\calt<<1 and slow
quenches with T\calt>>1. In the limit that T\calt\to\infty, we observe the
expected adiabatic response. For fast quenches, the relaxation to the final
equilibrium is controlled by the lowest quasinormal mode of the bulk scalar
dual to the quenched operator. For slow quenches, the system relaxes with a
(nearly) adiabatic response that is governed entirely by the late time profile
of the mass. We describe new renormalization scheme ambiguities in defining
gauge invariant observables for the theory with time dependant couplings.Comment: 78 pages, 17 figure
MURC/Cavin-4 and cavin family members form tissue-specific caveolar complexes
Polymerase I and transcript release factor (PTRF)/Cavin is a cytoplasmic protein whose expression is obligatory for caveola formation. Using biochemistry and fluorescence resonance energy transfer–based approaches, we now show that a family of related proteins, PTRF/Cavin-1, serum deprivation response (SDR)/Cavin-2, SDR-related gene product that binds to C kinase (SRBC)/Cavin-3, and muscle-restricted coiled-coil protein (MURC)/Cavin-4, forms a multiprotein complex that associates with caveolae. This complex can constitutively assemble in the cytosol and associate with caveolin at plasma membrane caveolae. Cavin-1, but not other cavins, can induce caveola formation in a heterologous system and is required for the recruitment of the cavin complex to caveolae. The tissue-restricted expression of cavins suggests that caveolae may perform tissue-specific functions regulated by the composition of the cavin complex. Cavin-4 is expressed predominantly in muscle, and its distribution is perturbed in human muscle disease associated with Caveolin-3 dysfunction, identifying Cavin-4 as a novel muscle disease candidate caveolar protein
Some Calculable Contributions to Holographic Entanglement Entropy
Using the AdS/CFT correspondence, we examine entanglement entropy for a
boundary theory deformed by a relevant operator and establish two results. The
first is that if there is a contribution which is logarithmic in the UV
cut-off, then the coefficient of this term is independent of the state of the
boundary theory. In fact, the same is true of all of the coefficients of
contributions which diverge as some power of the UV cut-off. Secondly, we show
that the relevant deformation introduces new logarithmic contributions to the
entanglement entropy. The form of some of these new contributions is similar to
that found recently in an investigation of entanglement entropy in a free
massive scalar field theory [1].Comment: 52 pages, no figure
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