565 research outputs found

    Statistical Origin of Gravity

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    Starting from the definition of entropy used in statistical mechanics we show that it is proportional to the gravity action. For a stationary black hole this entropy is expressed as S=E/2TS = E/ 2T, where TT is the Hawking temperature and EE is shown to be the Komar energy. This relation is also compatible with the generalised Smarr formula for mass.Comment: LaTex, 7 pages, no figure, minor clarifications, references added, to appear in Phys. Rev.

    Improved self-gain in deep submicrometer strained silicon-germanium pMOSFETs with HfSiOx/TiSiN gate stacks

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    The self-gain of surface channel compressively strained SiGe pMOSFETs with HfSiOx/TiSiN gate stacks is investigated for a range of gate lengths down to 55 nm. There is 125% and 700% enhancement in the self-gain of SiGe pMOSFETs compared with the Si control at 100 nm and 55 nm lithographic gate lengths, respectively. This improvement in the self-gain of the SiGe devices is due to 80% hole mobility enhancement compared with the Si control and improved electrostatic integrity in the SiGe devices due to less boron diffusion into the channel. At 55 nm gate length, the SiGe pMOSFETs show 50% less drain induced barrier lowering compared with the Si control devices. Electrical measurements show that the SiGe devices have larger effective channel lengths. It is shown that the enhancement in the self-gain of the SiGe devices compared with the Si control increases as the gate length is reduced thereby making SiGe pMOSFETs with HfSiOx/TiSiN gate stacks an excellent candidate for analog/mixed-signal applications

    A novel path delay fault simulator using binary logic

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    A novel path delay fault simulator for combinational logic circuits which is capable of detecting both robust and nonrobust paths is presented. Particular emphasis has been given for the use of binary logic rather than the multiple-valued logic as used in the existing simulators which contributes to the reduction of the overall complexity of the algorithm. A rule based approach has been developed which identifies all robust and nonrobust paths tested by a two-pattern test <V1,V2>, while backtracing from the POs to PIs in a depth-first manner. Rules are also given to find probable glitches and to determine how they propagate through the circuit, which enables the identification of nonrobust paths. Experimental results on several ISCAS'85 benchmark circuits demonstrate the efficiency of the algorithm

    Thermalization of horizon through asymptotic symmetry in three-dimensional massive gravity

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    Recently, black hole symmetries have been studied widely and it has been speculated that this procedure will lead to the deeper understanding of the black hole physics. Spontaneous symmetry breaking of the horizon symmetries is one of the very recent attempt to clarify black hole thermal physics. In this work, we are going to investigate the same in three dimensional massive gravity, including higher order of Riemann tensor. We observe that the idea also works well in this gravitational theory, thereby providing stronger demand of the viability of this idea.Comment: 17 Page

    Nutritional status vis-a-vis iodine deficiency in children of "Save Our Soul"children’s village in rural Varanasi: a micro-level study

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    Background: There is paucity of data with regard to the Iodine deficiency in an organized sector like SOS children’s village which is an independent, non-governmental, social development organization located in urban Varanasi. Uttar Pradesh is one of the endemic states for goiter. It is expected that similar situation of goiter may prevail in children as well. It is a matter of concern that micro nutrient deficiency and under-nutrition may exist side by side. The objectives of the study were to assess nutritional status and find out the extent of Iodine deficiency in the study subjects, to find out the association between under nutrition and Iodine deficiency and to find out the Iodine content of salt used for cooking in the family.Methods: 118 children of age group 6 to 15 years, from a Non-Governmental Organization (Save Our Soul) in Rural Varanasi constituted materials of the study. Consent from the director of the institution and assent from the individual children was taken prior to examination. All the subjects were examined clinically for the Presence of Goiter. They were subjected to weight and height recording following standard technique. Salt samples from the houses were tested by spot Iodine detection kit.Results: In case of 72.6% female and 91.3% male subjects, BMI for age was <100% of the respective reference values; in all 76.3% subjects belonged to this category. Presence of Goiter among male children was 34.7% and among female children it was 22.2% and overall it was 24.6%. Significant association was observed between nutritional status and iodine deficiency (p<0.05). In 37.5% of salt samples, iodine content was 7 ppm and rest 62.5% shows iodine content 15ppm.Conclusions: Nutritional status of the children under reference was far from being satisfactory. High prevalence of Goiter is matter of serious concern. Iodized salt consumption in the houses was up to the mark but Iodine content of the salt samples from houses was not satisfactory

    NLO Corrections to lepton pair production beyond the Standard Model at hadron colliders

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    We consider lepton pair production at a hadron collider in a class of effective theories with the relevant operators being four-fermion contact interaction. Despite the nonrenormalizable nature of the interaction, we explicitly demonstrate that calculating QCD corrections is both possible and meaningful. Calculating the corrections for various differential distributions, we show that these can be substantial and significantly different from those within the SM. Furthermore, the corrections have a very distinctive flavour dependence. And finally, the scale dependence of the cross sections are greatly reduced once the NLO corrections are taken into account.Comment: 23 pages, 14 figures, few typos corrected, written in JHEP styl

    Crypto-Harmonic Oscillator in Higher Dimensions: Classical and Quantum Aspects

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    We study complexified Harmonic Oscillator models in two and three dimensions. Our work is a generalization of the work of Smilga \cite{sm} who initiated the study of these Crypto-gauge invariant models that can be related to PTPT-symmetric models. We show that rotational symmetry in higher spatial dimensions naturally introduces more constraints, (in contrast to \cite{sm} where one deals with a single constraint), with a much richer constraint structure. Some common as well as distinct features in the study of the same Crypto-oscillator in different dimensions are revealed. We also quantize the two dimensional Crypto-oscillator.Comment: 17 pages, Latex, enlarges version, added ref.s., accepted in J.Phys.A, slight alteration in reference section and text, matches journal versio

    Hamilton-Jacobi Tunneling Method for Dynamical Horizons in Different Coordinate Gauges

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    Previous work on dynamical black hole instability is further elucidated within the Hamilton-Jacobi method for horizon tunneling and the reconstruction of the classical action by means of the null-expansion method. Everything is based on two natural requirements, namely that the tunneling rate is an observable and therefore it must be based on invariantly defined quantities, and that coordinate systems which do not cover the horizon should not be admitted. These simple observations can help to clarify some ambiguities, like the doubling of the temperature occurring in the static case when using singular coordinates, and the role, if any, of the temporal contribution of the action to the emission rate. The formalism is also applied to FRW cosmological models, where it is observed that it predicts the positivity of the temperature naturally, without further assumptions on the sign of the energy.Comment: Standard Latex document, typos corrected, refined discussion of tunneling picture, subsection 5.1 remove

    Characterisation of road bumps using smartphones

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    Introduction: Speed bumps are used as the main means of controlling vehicle speeds all over the world. It is not too infrequent, especially in the emerging economies, to have unmarked bumps that can be perilous for the passengers. Fortuitously, the roadways and mobile phone networks have grown simultaneously in emerging economies. This paper demonstrates the capability of smartphones placed inside the vehicles in characterisation of road bumps. The smart mobile phones have accelerometers and position sensors that can be useful for autonomous monitoring roads. This can empower the user community in monitoring of roads. However, the capability of the smartphone in discerning different types of speed bumps while travelling in heterogeneous vehicle types needs to be examined. Methods: A range of road vehicles is mathematically modelled as mass, spring, and damper systems. The mathematical model of the vehicle is excited with parameters analogous to some common speed bumps and its acceleration response is calculated. The accelerometer of a smartphone is validated by comparing it with high precision accelerometers. The acceleration response of the phone while passing over the corresponding road bumps, which was used in the model earlier, is recorded using an Android based application. The experiment is repeated for different classes of vehicles. Filters have been used to reduce noise in the signals. A time averaging technique has been employed to compress the collected data.Results and conclusions: The acceleration signals have been digitally processed to capture road bumps. The importance of using a mathematical model to understand the acceleration response of a vehicle has been established. Also, the use of pass filters to extract the signal of concern from the noisy data has been exhibited. The ability of the technique to discern different types of speed bumps while travelling in a variety of vehicle types has been demonstrated. This investigation demonstrates the potential to automatically monitor the condition of roadways obviating costly manual inspections. As smartphones are ubiquitous, the methodology has the potential to empower the user community in the maintenance of infrastructure

    Quasi-normal modes, area spectra and multi-horizon spacetimes

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    We suggest an interpretation for the highly damped QNM frequencies of the spherically symmetric multi-horizon spacetimes (Reissner-Nordstrom, Schwarzschild-deSitter, Reissner-Nordstrom-deSitter) following Maggiore's proposal about the link between the asymptotic QNM frequencies and the black hole thermodynamics. We show that the behavior of the asymptotic frequencies is easy to understand if one assumes that all of the horizons have the same equispaced area spectra. The QNM analysis is then consistent with the choice of the area spectra to be the one originally proposed for the black hole's horizon by Bekenstein: A=8\pi n (in Planck units). The interpretation of the highly damped QNM frequencies in the multi-horizon case is based on the similar grounds as in the single horizon (Schwarzschild) case, but it has some new features that are discussed in the paper.Comment: 8 pages, v2: no physics changed, some references added, few sentences added in the discussion part
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