204 research outputs found

    Reporting an Experience on Design and Implementation of e-Health Systems on Azure Cloud

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    Electronic Health (e-Health) technology has brought the world with significant transformation from traditional paper-based medical practice to Information and Communication Technologies (ICT)-based systems for automatic management (storage, processing, and archiving) of information. Traditionally e-Health systems have been designed to operate within stovepipes on dedicated networks, physical computers, and locally managed software platforms that make it susceptible to many serious limitations including: 1) lack of on-demand scalability during critical situations; 2) high administrative overheads and costs; and 3) in-efficient resource utilization and energy consumption due to lack of automation. In this paper, we present an approach to migrate the ICT systems in the e-Health sector from traditional in-house Client/Server (C/S) architecture to the virtualised cloud computing environment. To this end, we developed two cloud-based e-Health applications (Medical Practice Management System and Telemedicine Practice System) for demonstrating how cloud services can be leveraged for developing and deploying such applications. The Windows Azure cloud computing platform is selected as an example public cloud platform for our study. We conducted several performance evaluation experiments to understand the Quality Service (QoS) tradeoffs of our applications under variable workload on Azure.Comment: Submitted to third IEEE International Conference on Cloud and Green Computing (CGC 2013

    Study the impact of ketamine, clonidine and combination of ketamine-clonidine on cardiovascular system during pre and postoperatively: A double blind, placebo controlled study

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    Background: The use of ketamine as a sole anesthetic induces marked central sympathetic stimulation, causing increased heart rate, blood pressure (BP), and oxygen consumption (VO2). Both alpha 2-agonists and benzodiazepines have been used to attenuate these potentially harmful ketamine-induced responses.  Materials and Methods: After approval from institutional ethical committee and written informed consent, 120 adult patients, ASA physical status I and II, undergoing elective surgeries e.g. Open abdominal surgery, laparoscopic surgery, open urological surgery were included in this controlled, prospective, randomized, double-blind study. Patients were randomly (envelop randomization) allocated in 4 groups (n=30): Group K received IV ketamine (0.5mg/kg), Group C received IV clonidine (1.5μg/kg), Group KC received combination of IV ketamine (0.25mg/kg) and IV clonidine (0.75μg/kg) and Group P received IV normal saline (placebo). One envelop at a time was chosen by an anaesthesiologist, who was blinded to the preparation of study agents and administered the study drugs in the envelope one after the other, intravenously approximately 20 minutes before extubation. Results: Pre operative haemodynamic parameters like mean arterial pressure (MAP) and heart rate are comparable across the groups. There was statistically significant (two tailed p value < 0.001) rise in intra operative heart rate following intubation in groups K, KC and P. There was statistically significant increase in systolic blood pressure (SBP) in groups K and P (two tailed p value < 0.001). In group C and KC, there were significant fall in SBP, from the baseline values, following induction. Conclusion: The unwanted effects of the individual drugs like, haemodynamic alteration, hallucination or lower incidences of nausea and vomiting could be achieved by using half of the dose of each of the drugs in combination

    Synthetic Turbulence, Fractal Interpolation and Large-Eddy Simulation

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    Fractal Interpolation has been proposed in the literature as an efficient way to construct closure models for the numerical solution of coarse-grained Navier-Stokes equations. It is based on synthetically generating a scale-invariant subgrid-scale field and analytically evaluating its effects on large resolved scales. In this paper, we propose an extension of previous work by developing a multiaffine fractal interpolation scheme and demonstrate that it preserves not only the fractal dimension but also the higher-order structure functions and the non-Gaussian probability density function of the velocity increments. Extensive a-priori analyses of atmospheric boundary layer measurements further reveal that this Multiaffine closure model has the potential for satisfactory performance in large-eddy simulations. The pertinence of this newly proposed methodology in the case of passive scalars is also discussed

    Solving the Graceful Exit Problem in Superstring Cosmology

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    We briefly review the status of the ``graceful exit'' problem in superstring cosmology and present a possible resolution. It is shown that there exists a solution to this problem in two-dimensional dilaton gravity provided quantum corrections are incorporated. This is similar to the recently proposed solution of Rey. However, unlike in his case, in our one-loop corrected model the graceful exit problem is solved for any finite number of massless scalar matter fields present in the theory.Comment: 8 pages, RevTex. Based on talk given at Conference on Big Bang and Alternative Cosmologies: A Critical Appraisal, Bangalore, India, January, 199

    Prospects for GMRT to Observe Radio Waves from UHE Particles Interacting with the Moon

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    Ultra high energy (UHE) particles of cosmic origin impact the lunar regolith and produce radio signals through Askaryan effect, signals that can be detected by Earth based radio telescopes. We calculate the expected sensitivity for observation of such events at the Giant Metrewave Radio Telescope (GMRT), both for UHE cosmic rays (CR) and UHE neutrino interactions. We find that for 30 days of observation time a significant number of detectable events is expected above 102010^{20} eV for UHECR or neutrino fluxes close to the current limits. Null detection over a period of 30 days will lower the experimental bounds on UHE particle fluxes by magnitudes competitive to both present and future experiments at the very highest energies.Comment: 21 pages, 9 figure

    Exact solutions in two-dimensional string cosmology with back reaction

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    We present analytic cosmological solutions in a model of two-dimensional dilaton gravity with back reaction. One of these solutions exhibits a graceful exit from the inflationary to the FRW phase and is nonsingular everywhere. A duality related second solution is found to exist only in the ``pre-big-bang'' epoch and is singular at τ=0\tau = 0. In either case back reaction is shown to play a crucial role in determining the specific nature of these geometries.Comment: Shortened slightly, references added, to appear in Physical Review D (Rapid Communications). 16 pages, RevTex, 3 PostScript figure

    Gravitational wave radiometry: Mapping a stochastic gravitational wave background

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    The problem of the detection and mapping of a stochastic gravitational wave background (SGWB), either of cosmological or astrophysical origin, bears a strong semblance to the analysis of CMB anisotropy and polarization. The basic statistic we use is the cross-correlation between the data from a pair of detectors. In order to `point' the pair of detectors at different locations one must suitably delay the signal by the amount it takes for the gravitational waves (GW) to travel to both detectors corresponding to a source direction. Then the raw (observed) sky map of the SGWB is the signal convolved with a beam response function that varies with location in the sky. We first present a thorough analytic understanding of the structure of the beam response function using an analytic approach employing the stationary phase approximation. The true sky map is obtained by numerically deconvolving the beam function in the integral (convolution) equation. We adopt the maximum likelihood framework to estimate the true sky map that has been successfully used in the broadly similar, well-studied CMB map making problem. We numerically implement and demonstrate the method on simulated (unpolarized) SGWB for the radiometer consisting of the LIGO pair of detectors at Hanford and Livingston. We include `realistic' additive Gaussian noise in each data stream based on the LIGO-I noise power spectral density. The extension of the method to multiple baselines and polarized GWB is outlined. In the near future the network of GW detectors, including the Advanced LIGO and Virgo detectors that will be sensitive to sources within a thousand times larger spatial volume, could provide promising data sets for GW radiometry.Comment: 24 pages, 19 figures, pdflatex. Matched version published in Phys. Rev. D - minor change

    Behavior of Quasilocal Mass Under Conformal Transformations

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    We show that in a generic scalar-tensor theory of gravity, the ``referenced'' quasilocal mass of a spatially bounded region in a classical solution is invariant under conformal transformations of the spacetime metric. We first extend the Brown-York quasilocal formalism to such theories to obtain the ``unreferenced'' quasilocal mass and prove it to be conformally invariant. The appropriate reference term in this case is defined by generalizing the Hawking-Horowitz prescription, which was originally proposed for general relativity. For such a choice of reference term, the referenced quasilocal mass for a general spacetime solution is obtained. This expression is shown to be a conformal invariant provided the conformal factor is a monotonic function of the scalar field. We apply this expression to the case of static spherically symmetric solutions with arbitrary asymptotics to obtain the referenced quasilocal mass of such solutions. Finally, we demonstrate the conformal invariance of our quasilocal mass formula by applying it to specific cases of four-dimensional charged black hole spacetimes, of both the asymptotically flat and non-flat kinds, in conformally related theories.Comment: LaTeX, 31 pages, one ps figur

    Stau detection at neutrino telescopes in scenarios with supersymmetric dark matter

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    We have studied the detection of long-lived staus at the IceCube neutrino telescope, after their production inside the Earth through the inelastic scattering of high energy neutrinos. The theoretical predictions for the stau flux are calculated in two scenarios in which the presence of long-lived staus is naturally associated to viable supersymmetric dark matter. Namely, we consider the cases with superWIMP (gravitino or axino) and neutralino dark matter (along the coannihilation region). In both scenarios the maximum value of the stau flux turns out to be about 1 event/yr in regions with a light stau. This is consistent with light gravitinos, with masses constrained by an upper limit which ranges from 0.2 to 15 GeV, depending on the stau mass. Likewise, it is compatible with axinos with a mass of about 1 GeV and a very low reheating temperature of order 100 GeV. In the case of the neutralino dark matter this favours regions with a low value of tan(beta), for which the neutralino-stau coannihilation region occurs for smaller values of the stau mass. Finally, we study the case of a general supergravity theory and show how for specific choices of non-universal soft parameters the predicted stau flux can increase moderately.Comment: 26 pages, 7 figures. References added and minor changes. Final version to appear in JCA

    Hamiltonian thermodynamics of two-dimensional vacuum dilatonic black holes

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    We consider the Hamiltonian dynamics and thermodynamics of the two-dimensional vacuum dilatonic black hole in the presence of a timelike boundary with a fixed value of the dilaton field. A~canonical transformation, previously developed by Varadarajan and Lau, allows a reduction of the classical dynamics into an unconstrained Hamiltonian system with one canonical pair of degrees of freedom. The reduced theory is quantized, and a partition function of a canonical ensemble is obtained as the trace of the analytically continued time evolution operator. The partition function exists for any values of the dilaton field and the temperature at the boundary, and the heat capacity is always positive. For temperatures higher than βc1=λ/(2π)\beta_c^{-1} = \hbar\lambda/(2\pi), the partition function is dominated by a classical black hole solution, and the dominant contribution to the entropy is the two-dimensional Bekenstein-Hawking entropy. For temperatures lower than~βc1\beta_c^{-1}, the partition function remains well-behaved and the heat capacity is positive in the asymptotically flat space limit, in contrast to the corresponding limit in four-dimensional spherically symmetric Einstein gravity; however, in this limit, the partition function is not dominated by a classical black hole solution.Comment: 20 pages, REVTEX. Added a discussion on the boundary action and boundary terms in Sec. IIIA. Minor changes in Acknowledgements and Reference
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