3,950 research outputs found

    Your Sewing Machine - Its Care and Adjustment

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    PDF pages: 2

    Study of aerodynamic technology for single-cruise-engine V/STOL fighter/attack aircraft

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    A viable, single engine, supersonic V/STOL fighter/attack aircraft concept was defined. This vectored thrust, canard wing configuration utilizes an advanced technology separated flow engine with fan stream burning. The aerodynamic characteristics of this configuration were estimated and performance evaluated. Significant aerodynamic and aerodynamic propulsion interaction uncertainties requiring additional investigation were identified. A wind tunnel model concept and test program to resolve these uncertainties and validate the aerodynamic prediction methods were defined

    Randomized sham controlled trial of cranial microcurrent stimulation for symptoms of depression, anxiety, pain, fatigue and sleep disturbances in women receiving chemotherapy for early-stage breast cancer

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    Purpose Women with breast cancer may experience symptoms of depression, anxiety, pain, fatigue and sleep disturbances during chemotherapy. However, there are few modalities that address multiple, commonly occurring symptoms that may occur in individuals receiving cancer treatment. Cranial electrical stimulation (CES) is a treatment that is FDA cleared for depression, anxiety and insomnia. CES is applied via electrodes placed on the ear that deliver pulsed, low amplitude electrical current to the head. Methods This phase III randomized, sham-controlled study aimed to examine the effects of cranial microcurrent stimulation on symptoms of depression, anxiety, pain, fatigue, and sleep disturbances in women receiving chemotherapy for early-stage breast cancer. Patients were randomly assigned to either an actual or sham device and used the device daily for 1 h. The study was registered at clinicaltrials.gov, NCT00902330. Results The sample included N = 167 women with early-stage breast cancer. Symptom severity of depression, anxiety, and fatigue and sleep disturbances were generally mild to moderate. Levels of pain were low. Anxiety was highest prior to the initial chemotherapy and decreased over time. The primary outcome assessment (symptoms of depression, anxiety, fatigue, pain, sleep disturbances) revealed no statistically significant differences between the two groups, actual CES vs. sham. Conclusion In this study, women receiving chemotherapy for breast cancer experienced multiple symptoms in the mild to moderate range. Although there is no evidence for the routine use of CES during the chemotherapy period for symptom management in women with breast cancer, further symptom management modalities should be evaluated to mitigate symptoms of depression, anxiety, fatigue, pain and sleep disturbances over the course of chemotherapy

    Testing Lorentz and CPT symmetry with hydrogen masers

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    We present details from a recent test of Lorentz and CPT symmetry using hydrogen masers. We have placed a new limit on Lorentz and CPT violation of the proton in terms of a recent standard model extension by placing a bound on sidereal variation of the F = 1 Zeeman frequency in hydrogen. Here, the theoretical standard model extension is reviewed. The operating principles of the maser and the double resonance technique used to measure the Zeeman frequency are discussed. The characterization of systematic effects is described, and the method of data analysis is presented. We compare our result to other recent experiments, and discuss potential steps to improve our measurement.Comment: 26 pages, 16 figure

    Limit on Lorentz and CPT Violation of the Neutron Using a Two-Species Noble-Gas Maser

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    A search for sidereal variations in the frequency difference between co-located 129-Xe and 3-He Zeeman masers sets the most stringent limit to date on leading-order Lorentz and CPT violation involving the neutron, consistent with no effect at the level of 10^{-31} GeV

    Incompressible flow in porous media with fractional diffusion

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    In this paper we study the heat transfer with a general fractional diffusion term of an incompressible fluid in a porous medium governed by Darcy's law. We show formation of singularities with infinite energy and for finite energy we obtain existence and uniqueness results of strong solutions for the sub-critical and critical cases. We prove global existence of weak solutions for different cases. Moreover, we obtain the decay of the solution in LpL^p, for any p2p\geq2, and the asymptotic behavior is shown. Finally, we prove the existence of an attractor in a weak sense and, for the sub-critical dissipative case with α(1,2]\alpha\in (1,2], we obtain the existence of the global attractor for the solutions in the space HsH^s for any s>(N/2)+1αs > (N/2)+1-\alpha

    Recovery From Monocular Deprivation Using Binocular Deprivation: Experimental Observations and Theoretical Analysis

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    Ocular dominance (OD) plasticity is a robust paradigm for examining the functional consequences of synaptic plasticity. Previous experimental and theoretical results have shown that OD plasticity can be accounted for by known synaptic plasticity mechanisms, using the assumption that deprivation by lid suture eliminates spatial structure in the deprived channel. Here we show that in the mouse, recovery from monocular lid suture can be obtained by subsequent binocular lid suture but not by dark rearing. This poses a significant challenge to previous theoretical results. We therefore performed simulations with a natural input environment appropriate for mouse visual cortex. In contrast to previous work we assume that lid suture causes degradation but not elimination of spatial structure, whereas dark rearing produces elimination of spatial structure. We present experimental evidence that supports this assumption, measuring responses through sutured lids in the mouse. The change in assumptions about the input environment is sufficient to account for new experimental observations, while still accounting for previous experimental results

    Fast computation of the geoelectric field using the method of elementary current systems and planar Earth models

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    International audienceThe method of spherical elementary current systems provides an accurate modelling of the horizontal component of the geomagnetic variation field. The interpolated magnetic field is used as input to calculate the horizontal geoelectric field. We use planar layered (1-D) models of the Earth's conductivity, and assume that the electric field is related to the local magnetic field by the plane wave surface impedance. There are locations in which the conductivity structure can be approximated by a 1-D model, as demonstrated with the measurements of the Baltic Electromagnetic Array Research project. To calculate geomagnetically induced currents (GIC), we need the spatially integrated electric field typically in a length scale of 100km. We show that then the spatial variation of the electric field can be neglected if we use the measured or interpolated magnetic field at the site of interest. In other words, even the simple plane wave model is fairly accurate for GIC purposes. Investigating GIC in the Finnish high-voltage power system and in the natural gas pipeline, we find a good agreement between modelled and measured values, with relative errors less than 30% for large GIC values. Key words. Geomagnetism and paleomagnetism (geomagnetic induction; rapid time variations) ? Ionosphere (electric field and currents

    First Passage Time in a Two-Layer System

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    As a first step in the first passage problem for passive tracer in stratified porous media, we consider the case of a two-dimensional system consisting of two layers with different convection velocities. Using a lattice generating function formalism and a variety of analytic and numerical techniques, we calculate the asymptotic behavior of the first passage time probability distribution. We show analytically that the asymptotic distribution is a simple exponential in time for any choice of the velocities. The decay constant is given in terms of the largest eigenvalue of an operator related to a half-space Green's function. For the anti-symmetric case of opposite velocities in the layers, we show that the decay constant for system length LL crosses over from L2L^{-2} behavior in diffusive limit to L1L^{-1} behavior in the convective regime, where the crossover length LL^* is given in terms of the velocities. We also have formulated a general self-consistency relation, from which we have developed a recursive approach which is useful for studying the short time behavior.Comment: LaTeX, 28 pages, 7 figures not include
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