164 research outputs found
First Law, Counterterms and Kerr-AdS_5 Black Holes
We apply the counterterm subtraction technique to calculate the action and
other quantities for the Kerr--AdS black hole in five dimensions using two
boundary metrics; the Einstein universe and rotating Einstein universe with
arbitrary angular velocity. In both cases, the resulting thermodynamic
quantities satisfy the first law of thermodynamics. We point out that the
reason for the violation of the first law in previous calculations is that the
rotating Einstein universe, used as a boundary metric, was rotating with an
angular velocity that depends on the black hole rotation parameter. Using a new
coordinate system with a boundary metric that has an arbitrary angular
velocity, one can show that the resulting physical quantities satisfy the first
law.Comment: 19 pages, 1 figur
Scale Invariance and the AdS/CFT Correspondence
Using the AdS/CFT correspondence, we show that the Anti-de Sitter (AdS)
rotating (Kerr) black holes in five and seven dimensions provide us with
examples of non-trivial field theories which are scale, but not conformally
invariant. This is demonstrated by our computation of the actions and the
stress-energy tensors of the four and six dimensional field theories residing
on the boundary of these Kerr-AdS black holes spacetimes.Comment: 3 pages. LaTeX, IJMP style. Contribution to proceedings of DPF 2000,
held at Ohio State
Detection of FXIII gene V34L and fibrinogen β-gene -455G/A polymorphisms among Saudi Arabia population via polymerase chain reaction-reverse hybridization technique
FXIII gene Val34Leu variant appears to be associated with decreased risk of myocardial infarction and venous thromboembolism as well as with increased risk of intracerebral hemorrhage. Fibrinogen β-gene SNP -455G/A are associated with differences in the plasma levels of fibrinogen and severity of arterial disease. The aim of the present work was to study the prevalence of FXIII gene V34L and Fibrinogen β-gene -455G/A SNPs in Saudi population. Among 200 blood samples randomly collected from unrelated healthy Saudi subjects, FXIII gene V34L and Fibrinogen β-gene -455G/A SNPs were genotyped via cardiovascular disease (CVD) StripAssay (ViennaLab, Austria. Homozygous (V/V) and heterozygous (V/L) genotypes were detected with 96 and 4%, respectively, among FXIII gene V34L genotypes, whereas (L/L) genotype was not found. The allele frequency was 0.98 for V allele and 0.02 for L allele. Three genotypes of Fibrinogen β-gene -455G/A SNP (GG, GA and AA) were obtained and its prevalence (%) was 70, 25 and 5, respectively. The frequency of G allele was 0.825 and 0.175 for A allele. Prevalence of FXIII gene Vl34L polymorphism and its allele frequency are in line with other Asian populations. Distribution of β-gene -455G/A genotypes and allele frequency are in accordance with previous reports in different ethnic groups. This is the first time to report these polymorphisms in Saudi Arabia population. This study provides valuable information on Saudi genetic background in comparison with other populations. In addition, it serves as a template for future clinical research involving cardiovascular and cerebrovascular diseases.Key words: FXIII gene V34L, fibrinogen β-gene -455G/A, polymorphisms, Saudi Arabia
Higher Dimensional Taub-NUTs and Taub-Bolts in Einstein-Maxwell Gravity
We present a class of higher dimensional solutions to Einstein-Maxwell
equations in d-dimensions. These solutions are asymptotically locally flat,
de-Sitter, or anti-de Sitter space-times. The solutions we obtained depend on
two extra parameters other than the mass and the nut charge. These two
parameters are the electric charge, q and the electric potential at infinity,
V, which has a non-trivial contribution. We Analyze the conditions one can
impose to obtain Taub-Nut or Taub-Bolt space-times, including the
four-dimensional case. We found that in the nut case these conditions coincide
with that coming from the regularity of the one-form potential at the horizon.
Furthermore, the mass parameter for the higher dimensional solutions depends on
the nut charge and the electric charge or the potential at infinity.Comment: 11 pages, LaTe
A Bestiary of Higher Dimensional Taub-NUT-AdS Spacetimes
We present a menagerie of solutions to the vacuum Einstein equations in six,
eight and ten dimensions. These solutions describe spacetimes which are either
locally asymptotically adS or locally asymptotically flat, and which have
non-trivial topology. We discuss the global structure of these solutions, and
their relevance within the context of M-theory.Comment: 11 pages, LaTex(v4: Comments and references added
Association between polymorphisms of SLC6A3 and DRD1 genes and autism among Saudi Arabia Taif population using PCR-restriction fragment length polymorphism (PCR- RFLP)
The prevalence of autism in Saudi Arabia is 18 per 10,000, higher than the 13 per 10,000 reported in developed countries. The etiology of autism is still not completely understood. Different studies support the involvement of dopaminergic neurotransmitter system in the etiology of autism. Several lines of evidences suggest the role of some dopamine related genes, such as DRD1 and SLC6A3 in the etiology of autism. The aim of the present work was to study the possible role of rs2550936 A/C polymorphism at SLC6A3 locus as well as rs4532 A/G polymorphism at DRD1 locus in the etiology of autism among Saudi population. The polymorphisms of DRD1 and LC6A3 were genotyped in the case-control study using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Significant association as risk factor was found between autism and GA genotype of DRD1 [OR = 3.5 CI (1.04, 12.41*)] as well as CA genotype of SLC6A3 [OR = 2.53 CI (1.03, 6.26*)], while CC genotype of SLC6A3 revealed protective effect. In conclusion, possible risk genotypes for autism in the DRD1 and SLC6A3 genes were observed. This is the first report in Saudi Arabia population and Arab world. Therefore further investigations of these markers and other SNPs of SLC6A3 and DRD1 genes are considered in large replication samples with other causal factors to enable positive identification of risk genotypes and generalize obtained results.Key words: Etiology, polymorphism, autism, genotype
Gauge Theories with Time Dependent Couplings and their Cosmological Duals
We consider the N=4 SYM theory in flat 3+1 dimensional spacetime with a time
dependent coupling constant which vanishes at , like . In an
analogous quantum mechanics toy model we find that the response is singular.
The energy diverges at , for a generic state. In addition, if the
phase of the wave function has a wildly oscillating behavior, which does not
allow it to be continued past . A similar effect would make the gauge
theory singular as well, though nontrivial effects of renormalization could
tame this singularity and allow a smooth continuation beyond . The gravity
dual in some cases is known to be a time dependent cosmology which exhibits a
space-like singularity at . Our results, if applicable in the gauge theory
for the case of the vanishing coupling, imply that the singularity is a genuine
sickness and does not admit a meaningful continuation. When the coupling
remains non-zero and becomes small at , the curvature in the bulk becomes
of order the string scale. The gauge theory now admits a time evolution beyond
this point. In this case, a finite amount of energy is produced which possibly
thermalizes and leads to a black hole in the bulk.Comment: 45 pages, 1 figure; v2. minor modifications; v3: PRD version,
conclusions in the field theory case significantly revised to include
possible renormalization effects, quantum mechanics toy model unchanged,
abstract and introduction revised, additional subsection 4.1 adde
On Superspace Chern-Simons-like Terms
We search for superspace Chern-Simons-like higher-derivative terms in the low
energy effective actions of supersymmetric theories in four dimensions.
Superspace Chern-Simons-like terms are those gauge-invariant terms which cannot
be written solely in terms of field strength superfields and covariant
derivatives, but in which a gauge potential superfield appears explicitly. We
find one class of such four-derivative terms with N=2 supersymmetry which,
though locally on the Coulomb branch can be written solely in terms of field
strengths, globally cannot be. These terms are classified by certain Dolbeault
cohomology classes on the moduli space. We include a discussion of other
examples of terms in the effective action involving global obstructions on the
Coulomb branch.Comment: 23 pages; a reference and an author email correcte
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