20,181 research outputs found

    LEO life testing with different charge control

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    The effect of charge control on the performance of Nickel-Cadmium batteries is very important. The results of three tests performed in the Battery Test Centre of ESTEC are described. Two techniques were employed: (1) the tapering method well known for space applications, and (2) the temperature derivative technique (TDT) developed by ESTEC. In addition, a comparative study has been made between the behavior of a group of 3 batteries charged and discharged in parallel compared to an identical group discharged in parallel, but charged individually. An approach of evolution laws for the main electrical characteristics of cells is presented

    Recovery from Linear Measurements with Complexity-Matching Universal Signal Estimation

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    We study the compressed sensing (CS) signal estimation problem where an input signal is measured via a linear matrix multiplication under additive noise. While this setup usually assumes sparsity or compressibility in the input signal during recovery, the signal structure that can be leveraged is often not known a priori. In this paper, we consider universal CS recovery, where the statistics of a stationary ergodic signal source are estimated simultaneously with the signal itself. Inspired by Kolmogorov complexity and minimum description length, we focus on a maximum a posteriori (MAP) estimation framework that leverages universal priors to match the complexity of the source. Our framework can also be applied to general linear inverse problems where more measurements than in CS might be needed. We provide theoretical results that support the algorithmic feasibility of universal MAP estimation using a Markov chain Monte Carlo implementation, which is computationally challenging. We incorporate some techniques to accelerate the algorithm while providing comparable and in many cases better reconstruction quality than existing algorithms. Experimental results show the promise of universality in CS, particularly for low-complexity sources that do not exhibit standard sparsity or compressibility.Comment: 29 pages, 8 figure

    Practical approach to diastolic dysfunction in light of the new guidelines and clinical applications in the operating room and in the intensive care

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    There is growing evidence both in the perioperative period and in the field of intensive care (ICU) on the association between left ventricular diastolic dysfunction (LVDD) and worse outcomes in patients. The recent American Society of Echocardiography and European Association of Cardiovascular Imaging joint recommendations have tried to simplify the diagnosis and the grading of LVDD. However, both an often unknown pre-morbid LV diastolic function and the presence of several confounders—i.e., use of vasopressors, positive pressure ventilation, volume loading—make the proposed parameters difficult to interpret, especially in the ICU. Among the proposed parameters for diagnosis and grading of LVDD, the two tissue Doppler imaging-derived variables e′ and E/e′ seem most reliable. However, these are not devoid of limitations. In the present review, we aim at rationalizing the applicability of the recent recommendations to the perioperative and ICU areas, discussing the clinical meaning and echocardiographic findings of different grades of LVDD, describing the impact of LVDD on patients’ outcomes and providing some hints on the management of patients with LVDD

    Scattering of 42 MeV /6.7-pJ/ alpha particles from even isotopes of cadmium. Supplement 1 - Absolute cross sections

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    Absolute cross sections for scattering of 42 MeV alpha particles from even isotopes of cadmiu

    Elastic and inelastic scattering of 42-MeV alpha particles from even tellurium isotopes

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    Angular distributions of elastic and inelastic scattering of 42-MeV alpha particles measured for even tellurium isotope

    Carnival, dialogue, and drama, in the study and presentation of a literary and a liturgical text

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    The thesis considers three pieces of dialogue.1. Ivan and Alyosha in The Brothers Karamazov by Fyodor Dostoievski. 2 Dorothy Heathcote and some sixth form students in a classroom in Stockton on Tees. 3 A priest and congregation in a church in Carlisle. In each of these dialogues one factor can be isolated. It is the factor of "jolly relativity". It is a relativizing quality. It diminishes the absolute character of any speech. Mikhail Bakhtin's theory of dialogicality is applied to the classroom drama of Dorothy Heathcote and to the Eucharistic prayer said in a church. The thesis claims that what happens in the dialogue of Alyosha and Ivan in the first extract also happens in the other two dialogues

    Clinical and financial consequences of setting up an asthma clinic at St. Luke’s Hospital

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    The effects of setting up an asthma clinic were assessed in an audit study. A comparison was made between the quality and quantity of medication used by patients before and after attending the asthma clinic. The number and severity of exacerbations during a six month period before and a six month period after attending were also assessed. The cost of treatment before and after was also calculated. In 14% of patients, occupational factors, drugs or underlying lung disease were significant contributors to asthma. The number of acute episodes of severe asthma were reduced from 98 to 47, with hospital admissions falling from 26 to 1. Pulmonary function (%FEV1) improved in the group as a whole with the number of patients having their best FEV above 80% improving from 44 to 71. In spite of the expense of high cost drugs and the running costs of the clinic there were substantial savings largely from the reduced number of hospital admissions. The calculated annual cost fell from Lm 22,769 to Lm 10,654.peer-reviewe

    Atmospheric Analysis of the M/L- and M/T-Dwarf Binary Systems LHS 102 and Gliese 229

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    We present 0.9-2.5um spectroscopy with R~800 and 1.12-1.22um spectroscopy with R~5800 for the M dwarfs Gl 229A and LHS 102A, and for the L dwarf LHS 102B. We also report IZJHKL' photometry for both components of the LHS 102 system, and L' photometry for Gl 229A. The data are combined with previously published spectroscopy and photometry to produce flux distributions for each component of the kinematically old disk M/L-dwarf binary system LHS 102 and the kinematically young disk M/T-dwarf binary system Gliese 229. The data are analyzed using synthetic spectra generated by the latest "AMES-dusty" and "AMES-cond" models by Allard & Hauschildt. Although the models are not able to reproduce the overall slope of the infrared flux distribution of the L dwarf, most likely due to the treatment of dust in the photosphere, the data for the M dwarfs and the T dwarf are well matched. We find that the Gl 229 system is metal-poor despite having kinematics of the young disk, and that the LHS 102 system has solar metallicity. The observed luminosities and derived temperatures and gravities are consistent with evolutionary model predictions if the Gl 229 system is very young (age ~30 Myr) with masses (A,B) of (0.38,>0.007)M(sun), and the LHS 102 system is older, aged 1-10 Gyr with masses (A,B) of (0.19,0.07)M(sun).Comment: 29 pages incl. 13 figures and 5 tables;; accepted for publication in MNRA

    Random Filters for Compressive Sampling and Reconstruction

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    We propose and study a new technique for efficiently acquiring and reconstructing signals based on convolution with a fixed FIR filter having random taps. The method is designed for sparse and compressible signals, i.e., ones that are well approximated by a short linear combination of vectors from an orthonormal basis. Signal reconstruction involves a non-linear Orthogonal Matching Pursuit algorithm that we implement efficiently by exploiting the nonadaptive, time-invariant structure of the measurement process. While simpler and more efficient than other random acquisition techniques like Compressed Sensing, random filtering is sufficiently generic to summarize many types of compressible signals and generalizes to streaming and continuous-time signals. Extensive numerical experiments demonstrate its efficacy for acquiring and reconstructing signals sparse in the time, frequency, and wavelet domains, as well as piecewise smooth signals and Poisson processes
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