418 research outputs found

    Hawking Temperature in Taub-NUT (A)dS spaces via the Generalized Uncertainty Principle

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    Using the extended forms of the Heisenberg uncertainty principle from string theory and the quantum gravity theory, we drived Hawking temperature of a Taub-Nut-(A)dS black hole. In spite of their distinctive natures such as asymptotically locally flat and breakdown of the area theorem of the horizon for the black holes, we show that the corrections to Hawking temperature by the generalized versions of the the Heisenberg uncertainty principle increases like the Schwarzschild-(A)dS black hole and give the reason why the Taub-Nut-(A)dS metric may have AdS/CFT dual picture.Comment: version published in General Relativity and Gravitatio

    Fabry-Perot Absorption Line Spectroscopy of the Galactic Bar. I. Kinematics

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    We use Fabry-Perot absorption line imaging spectroscopy to measure radial velocities using the Ca II 8542 line in 3360 stars towards three lines of sight in the Milky Way's bar: Baade's Window and offset position at (l,b) ~ (+-5.0, -3.5). This sample includes 2488 bar red clump giants, 339 bar M/K-giants, and 318 disk main sequence stars. We measure the first four moments of the stellar velocity distribution of the red clump giants, and find it to be symmetric and flat-topped. We also measure the line-of-sight average velocity and dispersion of the red clump giants as a function of distance in the bar. We detect stellar streams at the near and far side of the bar with velocity difference > 30 km/s at l = +-5, but we do not detect two separate streams in Baade's Window. Our M-giants kinematics agree well with previous studies, but have dispersions systematically lower than those of the red clump giants by ~ 10 km/s. For the disk main sequence stars we measure a velocity dispersion of ~ 45 km/s for all three lines-of-sight, placing a majority of them in the thin disk within 3.5 kpc of the Sun, associated with the Sagittarius spiral arm. We measure the equivalent widths of the Ca II 8542 line that can be used to infer metallicities. We find indications of a metallicity gradient with Galactic longitude, with greater metallicity in Baade's Window. We find the bulge to be metal-rich, consistent with some previous studies.Comment: Accepted for publication in the Astrophysical Journal,16 pages, 12 figure

    Anticancer Evaluation of Adiantum venustum Don

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    Cancer is a malignant disease that is characterized by rapid and uncontrolled formation of abnormal cells which may mass together to form a growth or tumor, or proliferate throughout the body. Next to heart disease, cancer is a major killer of mankind. This study aims at a preliminary phytochemical screening and anticancer evaluation of Adiantum venustum Don against Ehrlich Ascites Carcinoma in animal model. The findings indicate that ethanolic extract of A. venustum Don possesses significant anticancer activity and also reduces elevated level of lipid peroxidation due to the presence of terpenoids and flavonoids. Thus, ethanolic extract of A. venustum Don could have vast therapeutic application against cancer

    Variant Histone H2A.Z Is Globally Localized to the Promoters of Inactive Yeast Genes and Regulates Nucleosome Positioning

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    H2A.Z is an evolutionary conserved histone variant involved in transcriptional regulation, antisilencing, silencing, and genome stability. The mechanism(s) by which H2A.Z regulates these various biological functions remains poorly defined, in part due to the lack of knowledge regarding its physical location along chromosomes and the bearing it has in regulating chromatin structure. Here we mapped H2A.Z across the yeast genome at an approximately 300-bp resolution, using chromatin immunoprecipitation combined with tiling microarrays. We have identified 4,862 small regions—typically one or two nucleosomes wide—decorated with H2A.Z. Those “Z loci” are predominantly found within specific nucleosomes in the promoter of inactive genes all across the genome. Furthermore, we have shown that H2A.Z can regulate nucleosome positioning at the GAL1 promoter. Within HZAD domains, the regions where H2A.Z shows an antisilencing function, H2A.Z is localized in a wider pattern, suggesting that the variant histone regulates a silencing and transcriptional activation via different mechanisms. Our data suggest that the incorporation of H2A.Z into specific promoter-bound nucleosomes configures chromatin structure to poise genes for transcriptional activation. The relevance of these findings to higher eukaryotes is discussed

    Exposure to mercury among 9-year-old children and neurobehavioural function

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    Mercury (Hg) is an environmental neurotoxicant whose main route of exposure in humans is the consumption of seafood. The aim of this study was to explore the relationship between Hg exposure at 9 years old and behaviour assessed at 9 and 11 years old. Study subjects were mother-child pairs participating in the INMA (Environment and Childhood) Project in Valencia (Spain). Total Hg (THg) was measured in hair samples from the children at 9 years old. Behaviour and emotions were assessed at 9 (n = 472) years and 11 (n = 385) years of age using the Child Behaviour Checklist test (CBCL) and the Conners Parents Rating Scale-Revised: Short Form (CPRS-R:S). Furthermore, the attention function was assessed by the Attention Network Test at 11 years old. Socio-demographic, lifestyle and dietary information was collected through questionnaires during pregnancy and childhood. Polymorphism in BDNF, APOE and GSTP1 were genotyped in cord blood DNA. Multivariable negative binomial regression models were built in order to study the association between THg concentrations and the scores obtained by the children at 9 and 11 years old. Effect modification by sex and genetic polymorphisms was assessed. The association between Hg levels and CBCL scores was positive (worse neurobehavioural development) for the CBCL internalizing and total problem scales (Incidence Rate Ratio [95% confidence interval] = 1.07 [1.01,1.13] and 1.05 [0.99, 1.11], respectively). The association between Hg and the externalizing and total problems CBCL scales and the Attention Deficit Hyperactivity Disorder (ADHD) index of the CPRS-R:S was different according to sex, with boys obtaining worse scores with increasing Hg, compared to girls. Statistically significant interactions were also observed for genetic polymorphisms affecting the association between early exposure to Hg and both CBCL and CPRS-R:S scores. In conclusion, postnatal Hg exposure is associated with poorer neurobehavioural development in 9- and 11-year-old children. Sex and the presence of certain genetic polymorphisms modified this association

    Warrants in underwritten IPOs: The Alternative Investment Market (AIM) experience

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    We examine the use of warrants as a part of underwriter compensation in IPOs listed on the Alternative Investment Market (AIM) of the London Stock Exchange. Our results show that, though warrant-issuing IPO firms are riskier, they are usually underwritten by reputable underwriters. Firms that are cash constrained at the time of their IPO are more likely to use warrants. Both market volatility and hot issue markets increase the likelihood of firms issuing warrants. We also find that warrant issuers are able to minimise their total costs of going public, even under a very light regulatory setting with regards non-cash compensation. They incur actual costs of 29.1%, but would have incurred greater costs of 33.8% had they not issued warrants to their underwriters. Overall, our results support the cost minimisation explanation of the use of warrants by UK IPO firms

    Totally biological composite aortic stentless valved conduit for aortic root replacement: 10-year experience

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    <p>Abstract</p> <p>Objectives</p> <p>To retrospectively analyze the clinical outcome of a totally biological composite stentless aortic valved conduit (No-React<sup>® </sup>BioConduit) implanted using the Bentall procedure over ten years in a single centre.</p> <p>Methods</p> <p>Between 27/10/99 and 19/01/08, the No-React<sup>® </sup>BioConduit composite graft was implanted in 67 patients. Data on these patients were collected from the in-hospital database, from patient notes and from questionnaires. A cohort of patients had 2D-echocardiogram with an average of 4.3 ± 0.45 years post-operatively to evaluate valve function, calcification, and the diameter of the conduit.</p> <p>Results</p> <p>Implantation in 67 patients represented a follow-up of 371.3 patient-year. Males were 60% of the operated population, with a mean age of 67.9 ± 1.3 years (range 34.1-83.8 years), 21 of them below the age of 65. After a mean follow-up of 7.1 ± 0.3 years (range of 2.2-10.5 years), more than 50% of the survivors were in NYHA I/II and more than 60% of the survivors were angina-free (CCS 0). The overall 10-year survival following replacement of the aortic valve and root was 51%. During this period, 88% of patients were free from valved-conduit related complications leading to mortality. Post-operative echocardiography studies showed no evidence of stenosis, dilatation, calcification or thrombosis. Importantly, during the 10-year follow-up period no failures of the valved conduit were reported, suggesting that the tissue of the conduit does not structurally change (histology of one explant showed normal cusp and conduit).</p> <p>Conclusions</p> <p>The No-React<sup>® </sup>BioConduit composite stentless aortic valved conduit provides excellent long-term clinical results for aortic root replacement with few prosthesis-related complications in the first post-operative decade.</p

    Effects of antiplatelet therapy on stroke risk by brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases: subgroup analyses of the RESTART randomised, open-label trial

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    Background Findings from the RESTART trial suggest that starting antiplatelet therapy might reduce the risk of recurrent symptomatic intracerebral haemorrhage compared with avoiding antiplatelet therapy. Brain imaging features of intracerebral haemorrhage and cerebral small vessel diseases (such as cerebral microbleeds) are associated with greater risks of recurrent intracerebral haemorrhage. We did subgroup analyses of the RESTART trial to explore whether these brain imaging features modify the effects of antiplatelet therapy
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