Asymptotic Quasinormal Modes of d-Dimensional Schwarzschild Black Hole with Gauss-Bonnet Correction

We obtain an analytic expression for the highly damped asymptotic quasinormal mode frequencies of the $d\geq 5$-dimensional Schwarzschild black hole modified by the Gauss-Bonnet term, which appears in string derived models of gravity. The analytic expression is obtained under the string inspired assumption that there exists a minimum length scale in the system and in the limit when the coupling in front of the Gauss-Bonnet term in the action is small. Although there are several similarities of this geometry with that of the Schwarzschild black hole, the asymptotic quasinormal mode frequencies are quite different. In particular, the real part of the asymptotic quasinormal frequencies for this class of single horizon black holes in not proportional to log(3).Comment: 10 pages, latex file, changes in several equations, changes in the abstract qualitative nature of conclusions unaffecte

Universal near-horizon conformal structure and black hole entropy

It is shown that a massless scalar probe reveals a universal near-horizon conformal structure for a wide class of black holes, including the BTZ. The central charge of the corresponding Virasoro algebra contains information about the black hole. With a suitable quantization condition on the central charge, the CFT associated with the black hole in our approach is consistent with the recent observation of Witten, where the dual theory for the BTZ in the AdS/CFT framework has been identified with the construction of Frenkel, Lepowsky and Meurman. This CFT admits the Fischer-Griess monster group as its symmetry. The logarithm of the dimension of a specific representation of the monster group has been identified by Witten as the entropy of the BTZ black hole. Our algebraic approach shows that a wide class of black holes share the same near-horizon conformal structure as that for the BTZ. With a suitable quantization condition, the CFT's for all these black holes in our formalism can be identified with the FLM model, although not through the AdS/CFT correspondence. The corresponding entropy for the BTZ provides a lower bound for the entropy of this entire class of black holes.Comment: References updated, text rearrange

Analysis of Fermi-LAT data from Tucana-II: Possible constraints on the Dark Matter models with an intriguing hint of a signal

Tucana-II (Tuc-II), a recently discovered and confirmed Ultra Faint Dwarf Spheroidal galaxy, has a high mass to light ratio as well as a large line-of-sight stellar velocity dispersion, thus making it an ideal candidate for an indirect dark matter (DM) search. In this paper, we have analyzed nine years of $\gamma$-ray data obtained from the \textit{Fermi}-LAT instrument from the direction of Tuc-II. The fact that a very weak significant $\gamma$-ray excess ($2.2\sigma$) over the background of Tuc-II have been detected from the location of this galaxy. We have observed that this excess of $\gamma$-ray emission from the of location Tuc-II rises with longer periods of data. If WIMP pair annihilation is assumed for this faint emission, for $b\bar{b}$ annihilation channel the test statistics (TS) value peaks at DM mass $\sim$ 14 GeV and for $\tau^{+}\tau^{-}$ annihilation channel it peaks at DM mass 4 GeV. It is then called for an estimation of the $95\%$ confidence level upper limit of the possible velocity weighted self-annihilation cross-section of the DM particles (WIMPs) within Tuc-II by fitting the observed $\gamma$-ray flux with spectra expected for DM annihilation. The estimated upper limits of the cross-sections from Tuc-II are then compared with two other dwarf galaxies that are considered to be good DM candidates in several studies. We have also compared our results with the cross-sections obtained in various popular theoretical models of the WIMPs to find that our results impose reasonable tight constraints on the parameter spaces of those DM models. In the concluding section, we compared our results with the similar results obtained from a combined dSph analysis by the \textit{Fermi}-LAT collaboration as well as the results obtained from the studies of DM in the dwarf galaxies by the major ground-based Cherenkov experiments.Comment: 23 pages, 16 figures, 7 table

Parametric Pension Reform with Higher Retirement Ages: A Computational Investigation of Alternatives for A Pay-As-You-Go Pension System

Cataloged from PDF version of article.This. paper discusses parametric reform options to control losses generated by a publicly managed pay-as-you-go (PAYG) pension system under alternative deficit reduction (reform) strategies involving changes in contribution and replacement rates and statutory retirement ages. Two different problems corresponding to different pension reform strategies are considered using computational techniques. The techniques are illustrated through exercises employing data for the financially troubled pension system in Turkey. (C) 2001 Elsevier Science B.V. All rights reserved

NAPO as a novel marker for apoptosis

Apoptosis or programmed cell death plays a pivotal role in embryonic development and maintenance of homeostasis. It is also involved in the etiology of pathophysiological conditions such as cancer, neurodegenerative, autoimmune, infectious, and heart diseases. Consequently, the study of apoptosis is now at center of both basic and clinical research applications. Therefore, sensitive and simple apoptosis detection techniques are required. Here we describe a monoclonal antibody–defined novel antigen, namely NAPO (negative in apoptosis), which is specifically lost during apoptosis. The anti-NAPO antibody recognizes two nuclear polypeptides of 60 and 70 kD. The antigen is maintained in quiescent and senescent cells, as well as in different phases of the cell cycle, including mitosis. Thus, immunodetection of NAPO antigen provides a specific, sensitive, and easy method for differential identification of apoptotic and nonapoptotic cells

Demographic Shock Transmission from Large to Small Countries: An Overlapping Generations CGE Analysis

Cataloged from PDF version of article.International commodity and capital flows provide channels for the transmission of the effects of demographic changes in large countries onto small open economies by altering the prices and interest rates facing them. This implies that even small countries with relatively young populations are potentially vulnerable to the effects of population aging in large industrial economies, To address this issue, which has largely been overlooked in previous literature. this paper considers the case of European Union and Turkey and shows, within an overlapping generations general equilibrium framework, that spillovers; of the demographic shock in Europe would intensify the changes that Turkey would experience during its own demographic transition. (C) 2001 Society for Policy Modeling. Published by Elsevier Science Inc

Soft X-ray Photoemission Studies of the HfO2/SiO2/Si System

Cataloged from PDF version of article.Soft x-ray photoelectron spectroscopy with synchrotron radiation was employed to study the valence-band offsets for the HfO2/SiO2/Si and HfO2/SiOxNy/Si systems. We obtained a valence-band offset difference of -1.05+/-0.1 eV between HfO2 (in HfO2/15 Angstrom SiO2/Si) and SiO2 (in 15 Angstrom SiO2/Si). There is no measurable difference between the HfO2 valence-band maximum positions of the HfO2/10 Angstrom SiOxNy/Si and HfO2/15 Angstrom SiO2/Si systems. (C) 2002 American Institute of Physics

On Resillience and Response Beyond Value Change: Transformation of Women's Movement in post-1980 Turkey

Cataloged from PDF version of article.This study examines the nature of, and reasons for, the transformation of the women's movement in Turkey in the post-1980 period by focusing on the origins, rationale, organization of two women's organizations and their interaction with political institutions. It seeks to answer two questions: in what ways do the post-1980 women's organizations differ from those of pre-1980 in Turkey? What factors have played a role in this transformation? In addressing these, this study critically examines two propositions put forward in the general literature on transformation in movements: emergence of postmaterialist values and changing political opportunity structures. Relying on evidence from Turkey, this study proposes three alternative factors adding nuance to these propositions in the general literature: the restrictions imposed by the 1980 coup on social movements bearing new frames of reference by activist women, the changing values and ideas of second wave feminism, and the limits of state-centered modernization for the women's movement in Turkey