5,787 research outputs found

    Physics with a very long neutrino factory baseline

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    We discuss the neutrino oscillation physics of a very long neutrino factory baseline over a broad range of lengths (between 6000 km and 9000 km), centered on the ``magic baseline'' (\sim 7500 km) where correlations with the leptonic CP phase are suppressed by matter effects. Since the magic baseline depends only on the density, we study the impact of matter density profile effects and density uncertainties over this range, and the impact of detector locations off the optimal baseline. We find that the optimal constant density describing the physics over this entire baseline range is about 5% higher than the average matter density. This implies that the magic baseline is significantly shorter than previously inferred. However, while a single detector optimization requires fine-tuning of the (very long) baseline length, its combination with a near detector at a shorter baseline is much less sensitive to the far detector location and to uncertainties in the matter density. In addition, we point out different applications of this baseline which go beyond its excellent correlation and degeneracy resolution potential. We demonstrate that such a long baseline assists in the improvement of the θ13\theta_{13} precision and in the resolution of the octant degeneracy. Moreover, we show that the neutrino data from such a baseline could be used to extract the matter density along the profile up to 0.24% at 1σ1 \sigma for large sin22θ13\sin^2 2 \theta_{13}, providing a useful discriminator between different geophysical models.Comment: 27 pages, 11 figures. Minor changes, references added; version to appear in Phys. Rev.

    Identifying Demand with Multidimensional Unobservables: A Random Functions Approach

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    We explore the identification of nonseparable models without relying on the property that the model can be inverted in the econometric unobservables. In particular, we allow for infinite dimensional unobservables. In the context of a demand system, this allows each product to have multiple unobservables. We identify the distribution of demand both unconditional and conditional on market observables, which allows us to identify several quantities of economic interest such as the (conditional and unconditional) distributions of elasticities and the distribution of price effects following a merger. Our approach is based on a significant generalization of the linear in random coefficients model that only restricts the random functions to be analytic in the endogenous variables, which is satisfied by several standard demand models used in practice. We assume an (unknown) countable support for the the distribution of the infinite dimensional unobservables.

    Molecular Dynamics of the Hammerhead Ribozyme

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    High-energy Atmospheric Muon Flux Expected at India-Based Neutrino Observatory

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    We calculate the zenith-angle dependence of conventional and prompt high-energy muon fluxes at India-Based Neutrino Observatory (INO) depth. This study demonstrates a possibility to discriminate models of the charm hadroproduction including the low-x QCD behaviour of hadronic cross-sections relevant at very high energies.Comment: 10 pages. 8 figures, 3 table

    Quantifying Isoniazid Levels in Small Hair Samples: A Novel Method for Assessing Adherence during the Treatment of Latent and Active Tuberculosis.

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    BackgroundTuberculosis (TB) is the leading cause of death from an infectious pathogen worldwide and the most prevalent opportunistic infection in people living with HIV. Isoniazid preventive therapy (IPT) reduces the incidence of active TB and reduces morbidity and mortality in HIV-infected patients independently of antiretroviral therapy. However, treatment of latent or active TB is lengthy and inter-patient variability in pharmacokinetics and adherence common. Current methods of assessing adherence to TB treatment using drug levels in plasma or urine assess short-term exposure and pose logistical challenges. Drug concentrations in hair assess long-term exposure and have demonstrated pharmacodynamic relevance in HIV.MethodsA large hair sample from a patient with active TB was obtained for assay development. Methods to pulverize hair and extract isoniazid were optimized and then the drug detected by liquid chromatography/ tandem mass spectrometry (LC/MS-MS). The method was validated for specificity, accuracy, precision, recovery, linearity and stability to establish the assay's suitability for therapeutic drug monitoring (TDM). Hair samples from patients on directly-observe isoniazid-based latent or active TB therapy from the San Francisco Department of Public Health TB clinic were then tested.ResultsOur LC/MS-MS-based assay detected isoniazid in quantities as low as 0.02ng/mg using 10-25 strands hair. Concentrations in spiked samples demonstrated linearity from 0.05-50ng/mg. Assay precision and accuracy for spiked quality-control samples were high, with an overall recovery rate of 79.5%. In 18 patients with latent or active TB on treatment, isoniazid was detected across a wide linear dynamic range.ConclusionsAn LC-MS/MS-based assay to quantify isoniazid levels in hair with performance characteristics suitable for TDM was developed and validated. Hair concentrations of isoniazid assess long-term exposure and may be useful for monitoring adherence to latent or active TB treatment in the setting of HIV

    Using robot operating system (ROS) and single board computer to control bioloid robot motion

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    This paper presents a research study on the adaptation of a novel technique for placing a programmable component over the structural component of a Robotis Bioloid humanoid robot. Assimilating intelligence plays an important role in the field of robotics that enables a computer to model or replicate some of the intelligent behaviors of human beings but with minimal human intervention. As a part of this effort, this paper revises the Bioloid robot structure so as to be able to control the robotic movement via a single board computer Beaglebone Black (BBB) and Robot operating system (ROS). ROS as the development frame work in conjunction with the main BBB controller that integrates robotic functions is an important aspect of this research, and is a first of its kind approach. A full ROS computation has been developed by which an API that will be usable by high level software using ROS services has also been developed. The human like body structure of the Bioloid robot and BeagleBone Black running ROS along with the intellectual components are used to make the robot walk efficiently

    Synthesis of bulk, dense, nanocrystalline yttrium aluminum garnet from amorphous powders

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    Amorphous powders of Al2O3x2014;37.5 mol% Y2O3 (yttrium aluminum garnet (YAG)) were prepared by coprecipitation, decomposed at 800xB0;C, and hot-pressed uniaxally at low temperature (600xB0;C) and a moderate pressure (750 MPa). Optimum conditions yielded microstructures with only 2% porosity and partial crystallization of YAG. Further processing using high quasi-hydrostatic pressure (1 GPa) at 1000xB0;C enabled the production of fully crystallized YAG with gt;96% relative density and a nanocrystalline grain size of x223C;70 nm. 13
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