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Jul 26, 2018
07/18

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Government of Tamil Nadu

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Tamil Nadu Gazette Date: 2009-3-16 Gazette Number: 75 Gazette Type: Extraordinary Part Number: Part II—Section 2 Extraordinary Type: Notifications or Orders of interest to a section of the public issued by Secretariat Departments. Subject: MUNICIPAL ADMINISTRATION AND WATER SUPPLY DEPARTMENT URL: Original Source

Topic: Tamil Nadu Gazette

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Sep 22, 2013
09/13

by
Andreas Luscher; Andreas Laeuchli

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We study the field dependence of the antiferromagnetic spin-1/2 Heisenberg model on the square lattice by means of exact diagonalizations. In a first part, we calculate the spin-wave velocity, the spin-stiffness, and the magnetic susceptibility and thus determine the microscopic parameters of the low-energy long-wavelength description. In a second part, we present a comprehensive study of dynamical spin correlation functions for magnetic fields ranging from zero up to saturation. We find that...

Source: http://arxiv.org/abs/0812.3420v3

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Sep 23, 2013
09/13

by
J. P. May

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The construction of E infinity ring spaces and thus E infinity ring spectra from bipermutative categories gives the most highly structured way of obtaining the K-theory commutative ring spectra. The original construction dates from around 1980 and has never been superseded, but the original details are difficult, obscure, and slightly wrong. We rework the construction in a much more elementary fashion.

Source: http://arxiv.org/abs/0903.2818v1

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Sep 23, 2013
09/13

by
L. R. Bedin; M. Salaris; G. Piotto; J. Anderson; I. R. King; S. Cassisi

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We use 14 orbits of ACS observations to reach the end of the white-dwarf cooling sequence in the globular cluster M4. Our photometry and completeness tests show that the end is located at magnitude m_F606W = 28.5+/-0.1, which implies an age of 11.6+/-0.6 Gyr (internal errors only). This is consistent with the age from fits to the main sequence turn-off (12.0+/-1.4 Gyr).

Source: http://arxiv.org/abs/0903.2839v1

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Sep 23, 2013
09/13

by
J. -F. Desmurs; C. Codella; J. Santiago-Garcia; M. Tafalla; R. Bachiller

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We have performed observations of water maser emission towards a sample of low-mass protostars, in order to investigate the properties of jets associated with the earliest stages of star formation and their interaction with the surrounding medium. The main aim is to measure the absolute positions and proper motions of the H_2O spots in order to investigate the kinematics of the region from where the jet is launched. We imaged the protostars in the nearby region NGC 1333-IRAS 4 in the water...

Source: http://arxiv.org/abs/0903.2770v1

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Sep 23, 2013
09/13

by
M. Grossi; S. di Serego Alighieri; C. Giovanardi; G. Gavazzi; R. Giovanelli; M. P. Haynes; B. R. Kent; S. Pellegrini; S. Stierwalt; G. Trinchieri

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We present the analysis of the HI content of a sample of early-type galaxies (ETGs) in low-density environments (LDEs) using the data set provided by the Arecibo Legacy Fast ALFA (ALFALFA) survey. We compare their properties to the sample in the Virgo cluster that we studied in a previous paper (di Serego Alighieri et al. 2007, Paper I). We have selected a sample of 62 nearby ETGs (V < 3000 km/s) in an area of the sky where the ALFALFA data are already available (8h -17). In both cases it is...

Source: http://arxiv.org/abs/0903.0602v3

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Sep 21, 2013
09/13

by
Larry Guth

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Let M be a closed 3-manifold which can be triangulated with N simplices. We prove that any map from M to a genus 2 surface has Hopf invariant at most C^N. Let X be a closed oriented hyperbolic 3-manifold with injectivity radius less than epsilon at one point. If there is a degree non-zero map from M to X, then we prove that epsilon is at least C^{-N}.

Source: http://arxiv.org/abs/0709.1247v2

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Jul 20, 2013
07/13

by
Adam Sierakowski

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Let (A,G) be a C*-dynamical system with G discrete. In this paper we investigate the ideal structure of the reduced crossed product C*-algebra and in particular we determine sufficient - and in some cases also necessary - conditions for A to separate the ideals in Ax_rG. When A separates the ideals in Ax_rG, then there is a one-to-one correspondence between the ideals in Ax_rG and the invariant ideals in A. We extend the concept of topological freeness and present a generalization of the...

Source: http://arxiv.org/abs/0804.3772v2

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Sep 23, 2013
09/13

by
Charles P. Meaney; Tim Duty; Ross H. McKenzie; Gerard J. Milburn

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We consider the steady states of a harmonic oscillator coupled so strongly to a two-level system (a qubit) that the rotating wave approximation cannot be made. The Hamiltonian version of this model is known as the $E\otimes\beta$ Jahn-Teller model. The semiclassical version of this system exhibits a fixed point bifurcation, which in the quantum model leads to a ground state with substantial entanglement between the oscillator and the qubit. We show that the dynamical bifurcation survives in a...

Source: http://arxiv.org/abs/0903.2681v1

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Sep 23, 2013
09/13

by
Pierre Andreoletti

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We study a random walk in a random environment (RWRE) on $\Z^d$, $1 \leq d < +\infty$. The main assumptions are that conditionned on the environment the random walk is reversible. Moreover we construct our environment in such a way that the walk can't be trapped on a single point like in some particular RWRE but in some specific d-1 surfaces. These surfaces are basic surfaces with deterministic geometry. We prove that the local time in the neighborhood of these surfaces is driven by a...

Source: http://arxiv.org/abs/0903.2696v1

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Sep 20, 2013
09/13

by
Rasmus Villemoes

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Given a set equipped with a transitive action of a group, we define the notion of an almost invariant coloring of the set. We consider the mapping class group orbit of a multicurve on a compact surface, and prove that in the case of genus at least two, no such almost invariant coloring exists. Conversely, in the case of a closed torus, one may find almost invariant colorings using arbitrarily many colors.

Source: http://arxiv.org/abs/0802.3000v2

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Sep 23, 2013
09/13

by
Javier Cilleruelo; D. S. Ramana; Olivier Ramare

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When $A$ and $B$ are subsets of the integers in $[1,X]$ and $[1,Y]$ respectively, with $|A| \geq \alpha X$ and $|B| \geq \beta X$, we show that the number of rational numbers expressible as $a/b$ with $(a,b)$ in $A \times B$ is $\gg (\alpha \beta)^{1+\epsilon}XY$ for any $\epsilon > 0$, where the implied constant depends on $\epsilon$ alone. We then construct examples that show that this bound cannot in general be improved to $\gg \alpha \beta XY$. We also resolve the natural generalisation...

Source: http://arxiv.org/abs/0903.2714v1

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Sep 23, 2013
09/13

by
Yudi Santoso

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We review the phenomenology of gravitino dark matter within supergravity framework. Gravitino can be dark matter if it is the lightest supersymmetric particle, which is stable if R-parity is conserved. There are several distinct scenarios depending on what the next to lightest supersymmetric particle (NLSP) is. We discuss the constraints and summarize the phenomenology of neutralino, stau, stop and sneutrino NLSPs.

Source: http://arxiv.org/abs/0903.2860v1

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Sep 22, 2013
09/13

by
L. Qian; M. A. Abramowicz; P. C. Fragile; J. Horak; M. Machida; O. Straub

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We construct a new family of analytic models of black hole accretion disks in dynamical equilibria. Our construction is based on assuming distributions of angular momentum and entropy. For a particular choice of the distribution of angular momentum, we calculate the shapes of equipressure surfaces. The equipressure surfaces we find are similar to those in thick, slim and thin disks, and to those in ADAFs.

Source: http://arxiv.org/abs/0812.2467v2

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Sep 23, 2013
09/13

by
Frans Snik; Radek Melich; Christoph Keller

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We present the design and the prototype of the Small Synoptic Second Solar Spectrum Telescope (S5T), which can autonomously measure scattering polarization signals on a daily basis with large sensitivity and accuracy. Its data will be used to investigate the nature of weak, turbulent magnetic fields through the Hanle effect in many lines. Also the relation between those fields and the global solar dynamo can be revealed by spanning the observations over a significant fraction of a solar cycle....

Source: http://arxiv.org/abs/0903.2730v1

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Sep 23, 2013
09/13

by
Nima Arkani-Hamed; Freddy Cachazo; Clifford Cheung; Jared Kaplan

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The simplicity and hidden symmetries of (Super) Yang-Mills and (Super)Gravity scattering amplitudes suggest the existence of a "weak-weak" dual formulation in which these structures are made manifest at the expense of manifest locality. We suggest that this dual description lives in (2,2) signature and is naturally formulated in twistor space. We recast the BCFW recursion relations in an on-shell form that begs to be transformed into twistor space. Our twistor transformation is...

Source: http://arxiv.org/abs/0903.2110v2

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Sep 23, 2013
09/13

by
Dennis E. White

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Let $\{h_1,h_2,...\}$ be a set of algebraically independent variables. We ask which vectors are extreme in the cone generated by $h_ih_j-h_{i+1}h_{j-1}$ ($i\geq j>0$) and $h_i$ ($i>0$). We call this cone the cone of log concavity. More generally, we ask which vectors are extreme in the cone generated by Schur functions of partitions with $k$ or fewer parts. We give a conjecture for which vectors are extreme in the cone of log concavity. We prove the characterization in one direction and...

Source: http://arxiv.org/abs/0903.2831v1

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Sep 21, 2013
09/13

by
L. Dunne; R. J. Ivison; S. Maddox; M. Cirasuolo; A. M. Mortier; S. Foucaud; E. Ibar; O. Almaini; C. Simpson; R. McLure

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We have studied the uJy radio properties of K-selected galaxies detected in the Ultra-Deep Survey portion of UKIDSS using 610- and 1,400-MHz images from the VLA and GMRT. These deep radio mosaics, combined with the largest and deepest K image currently available, allow high-S/N detections of many K-selected sub-populations, including sBzK and pBzK star-forming and passive galaxies. We find a strong correlation between the radio and K fluxes and a linear relationship between SFR and K...

Source: http://arxiv.org/abs/0808.3139v2

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Sep 23, 2013
09/13

by
Helmut Satz

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Quantum chromodynamics predicts that the interaction between its fundamental constituents, quarks and gluons, can lead to different states of strongly interacting matter, dependent on its temperature and baryon density. We first survey the possible states of matter in QCD and discuss the transition from a color-confining hadronic phase to a plasma of deconfined colored quarks and gluons. Next, we summarize the results from non-perturbative studies of QCD at finite temperature and baryon...

Source: http://arxiv.org/abs/0903.2778v1

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Sep 23, 2013
09/13

by
Lisa Winter; Richard Mushotzky; Yuichi Terashima; Yoshihiro Ueda

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The fraction of Compton thick sources is one of the main uncertainties left in understanding the AGN population. The Swift Burst Alert Telescope (BAT) all-sky survey, for the first time gives us an unbiased sample of AGN for all but the most heavily absorbed sources (log NH > 25). Still, the BAT spectra (14 - 195 keV) are time-averaged over months of observations and therefore hard to compare with softer spectra from the Swift XRT or other missions. This makes it difficult to distinguish...

Source: http://arxiv.org/abs/0903.2802v1

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Sep 20, 2013
09/13

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M. J. Lehner; C. -Y. Wen; J. -H. Wang; S. L. Marshall; M. E. Schwamb; Z. -W. Zhang; F. B. Bianco; J. Giammarco; R. Porrata; C. Alcock; T. Axelrod; Y. -I. Byun; W. P. Chen; K. H. Cook; R. Dave; S. -K. King; T. Lee; H. -C. Lin; S. -Y. Wang

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The Taiwanese-American Occultation Survey (TAOS) operates four fully automatic telescopes to search for occultations of stars by Kuiper Belt Objects. It is a versatile facility that is also useful for the study of initial optical GRB afterglows. This paper provides a detailed description of the TAOS multi-telescope system, control software, and high-speed imaging.

Source: http://arxiv.org/abs/0802.0303v2

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Sep 18, 2013
09/13

by
Dev P. Sinha

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We present two models for the space of knots which have endpoints at fixed boundary points in a manifold with boundary, one model defined as an inverse limit of spaces of maps between configuration spaces and another which is cosimplicial. These models build on the calculus of isotopy functors and are weakly homotopy equivalent to knot spaces when the ambient dimension is greater than three. The mapping space model, and the evaluation map on which it builds, is suitable for analysis through...

Source: http://arxiv.org/abs/math/0202287v7

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Sep 23, 2013
09/13

by
Jose M. Fernandez; Matthew J. Holman; Joshua N. Winn; Guillermo Torres; Avi Shporer; Tsevi Mazeh; Gilbert A. Esquerdo; Mark E. Everett

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We present photometry of six transits of the exoplanet XO-2b. By combining the light-curve analysis with theoretical isochrones to determine the stellar properties, we find the planetary radius to be 0.996 +0.031/-0.018 rjup and the planetary mass to be 0.565 +/- 0.054 mjup. These results are consistent with those reported previously, and are also consistent with theoretical models for gas giant planets. The mid-transit times are accurate to within 1 min and are consistent with a constant...

Source: http://arxiv.org/abs/0903.2687v1

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Sep 23, 2013
09/13

by
V. F. Krotov

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Here the probability density of relativistic particles coordinates, satisfying the formal conditions of the quantum mechanics and the special relativity, is determined (under textbooks view, such density does not exist). It is specified for the boson, neutral and charged, scalar and vector, including the photon, the electron. Uniqueness of this design has been proved. This is a relativistic invariant, describing the probability of the particle observation in points of space-time. The time is...

Source: http://arxiv.org/abs/0903.2725v1

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Sep 20, 2013
09/13

by
Peter K. F. Kuhfittig

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The purpose of this paper is to examine the possible existence or construction of traversable wormholes supported by generalized Chaplygin gas (GCG) by starting with a general line element and the Einstein tensor, together with the equation of state, thereby continuing an earlier study by the author of wormholes supported by phantom energy. Numerical techniques are used to demonstrate the existence of wormhole spacetimes that (1) meet the flare-out conditions at the throat, (2) are traversable...

Source: http://arxiv.org/abs/0802.3656v3

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Jul 22, 2013
07/13

by
R. Valiante; F. Matteucci; S. Recchi; F. Calura

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The aim of this work is the computation of the cosmic Type Ia supernova rates at very high redshifts (z>2). We adopt various progenitor models in order to predict the number of explosions in different scenarios for galaxy formation and to check whether it is possible to select the best delay time distribution model, on the basis of the available observations of Type Ia supernovae. We also computed the Type Ia supernova rate in typical elliptical galaxies of different initial luminous masses...

Source: http://arxiv.org/abs/0807.2354v2

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Sep 18, 2013
09/13

by
Josef Ludescher; Ralf Hofmann

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Based on the postulate that photon propagation is governed by an SU(2) gauge principle we numerically compute the one-loop dispersion for thermalized photon propagation on the radiatively induced mass shell. Formerly, the dispersion was addressed by assuming $p^2=0$. While this approximation turns out to be excellent for temperatures $\le 2 T_{\tiny{CMB}}$ the exact result exhibits a much faster (power-like) shrinking of the gap in the black-body spectral intensity with rising temperature. Our...

Source: http://arxiv.org/abs/0806.0972v2

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Sep 18, 2013
09/13

by
R. Lipperheide; U. Wille

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Spin-polarized electron transport in diluted magnetic semiconductors (DMS) in the paramagnetic phase is described within the thermoballistic transport model. In this (semiclassical) model, the ballistic and diffusive transport mechanisms are unified in terms of a thermoballistic current in which electrons move ballistically across intervals enclosed between arbitrarily distributed points of local thermal equilibrium. The contribution of each interval to the current is governed by the momentum...

Source: http://arxiv.org/abs/0809.4353v2

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Sep 23, 2013
09/13

by
Guo-Li Liu

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Topcolor-assisted technicolor (TC2) model predicts the existence of the top-pions and the CP-even top-Higgs with large flavor-changing couplings to the top quark, which at tree-level can mediate the top quark three-body decay t -> cb\bar{b}. In this work we study this decay, showing the dependence of the decay rate on the relevant TC2 parameters and comparing the results with the predictions in the minimal supersymmetric model. We find that the decay rate in the TC2 model is much larger than...

Source: http://arxiv.org/abs/0903.2619v1

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Sep 23, 2013
09/13

by
Alexander John; Andreas Schadschneider; Debashish Chowdhury; Katsuhiro Nishinari

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We report experimental results on unidirectional traffic-like collective movement of ants on trails. Our work is primarily motivated by fundamental questions on the collective spatio-temporal organization in systems of interacting motile constituents driven far from equilibrium. Making use of the analogies with vehicular traffic, we analyze our experimental data for the spatio-temporal organisation of the ants on the trail. From this analysis, we extract the flow-density relation as well as the...

Source: http://arxiv.org/abs/0903.2717v1

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Sep 18, 2013
09/13

by
V. Weith; A. Krekhov; W. Zimmermann

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We present a theoretical analysis of phase separation in the presence of a spatially periodic forcing of wavenumber q traveling with a velocity v. By an analytical and numerical study of a suitably generalized 2d-Cahn-Hilliard model we find as a function of the forcing amplitude and the velocity three different regimes of phase separation. For a sufficiently large forcing amplitude a spatially periodic phase separation of the forcing wavenumber takes place, which is dragged by the forcing with...

Source: http://arxiv.org/abs/0809.0211v2