698 research outputs found

    Measurement of Solar Cell Parameters with Dark Forward I-V Characteristics

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    The grade of a solar cell depends mainly on the quality of the starting material. During the production of this material, many impurities are left in the bulk material and form defect levels in the band-gap, which act as generation-recombination centers or charge carrier traps. These levels influence the efficiency of solar cells. Therefore knowledge of the parameters of these levels, e.g., energy position, capture cross section and concentration, is very useful for solar cell engineering. In this paper emphasis is placed on a simple and fast method for obtaining these parameters, namely measurements of dark characteristics. Preliminary results are introduced, together with the difficulties and limits of this method.

    The Enhanced Reading Opportunities Study: Early Impact and Implementation Findings

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    This report presents early findings from a demonstration and random assignment evaluation of two supplemental literacy programs that aim to improve the reading comprehension skills and school performance of struggling ninth-grade readers. On average, the programs produced a positive, statistically significant impact on reading comprehension among students

    Extension of effort for lunar flight handbook detailed technical report

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    Lunar flight handbook - orbital departure windows, libration points, and lunar flight orbit estimation, theory, and operation

    COMPARISON OF ISOMETRIC AND DYNAMIC METHODS OF STRENGTH TRAINING PROGRAM

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    The purpose of this study was to determine the difference in the quality of muscle strength employing two methods of strength training (isometric, dynamic). Nineteen male university students volunteered to participate in the experiment, encompassing a five week strength training sessions. The dynamic method was applied to the elbow flexion and extension of the right side (load totalling 60 % of maximal performance) and the isometric method applied on the same muscle groups of the left side (maximal voluntary isometric contraction). Pre- and post-test measurements included maximal isometric strength, the angle a expressed the speed of increasing muscle strength and the number of repetitions performed for each exercise (at a of load 60 % max), as a measure of muscle endurance. No differences were found between the results of strength training when using both methods (isometric, dynamic). A five week training program improved the isometric force by about 8-14 % of pre-test values, and by about 34-54 % in repetition exercises with the load. No differences were exhibited in the rate of the speed of increasing muscle strength

    Automating embedded analysis capabilities and managing software complexity in multiphysics simulation part II: application to partial differential equations

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    A template-based generic programming approach was presented in a previous paper that separates the development effort of programming a physical model from that of computing additional quantities, such as derivatives, needed for embedded analysis algorithms. In this paper, we describe the implementation details for using the template-based generic programming approach for simulation and analysis of partial differential equations (PDEs). We detail several of the hurdles that we have encountered, and some of the software infrastructure developed to overcome them. We end with a demonstration where we present shape optimization and uncertainty quantification results for a 3D PDE application

    Distributed-Pair Programming can work well and is not just Distributed Pair-Programming

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    Background: Distributed Pair Programming can be performed via screensharing or via a distributed IDE. The latter offers the freedom of concurrent editing (which may be helpful or damaging) and has even more awareness deficits than screen sharing. Objective: Characterize how competent distributed pair programmers may handle this additional freedom and these additional awareness deficits and characterize the impacts on the pair programming process. Method: A revelatory case study, based on direct observation of a single, highly competent distributed pair of industrial software developers during a 3-day collaboration. We use recordings of these sessions and conceptualize the phenomena seen. Results: 1. Skilled pairs may bridge the awareness deficits without visible obstruction of the overall process. 2. Skilled pairs may use the additional editing freedom in a useful limited fashion, resulting in potentially better fluency of the process than local pair programming. Conclusion: When applied skillfully in an appropriate context, distributed-pair programming can (not will!) work at least as well as local pair programming

    THE ACCURACY OF THE SKI-JUMPER'S TAKE-OFF

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    Introduction The Ski-jumper's take-off is the key phase in Ski-jumping. The difficulty lies in the take-off is done a t great speed (20-30 m.6- ) and in a very short amount of time (0.2-0,4sec.). Based on multifactor theory .We have defined 5 factors which are necessary to solve in one movement act: vigour, accuracy, aerodynamics, rotation, arm activity (VAVERKA, 1987).The take-off is accurate in the moment when the acceleration of the center of gravity is finished and passes through the edge of the take-off area. Problem The main goals of t h i s paper are: - quantification of the take-off accuracy (kinematic and dynamic Aspect), - the relation of the accuracy t o the other factors of the take-off and to final performance in ski-jumping, - to create a model of take-off accuracy (kinematic and dynamic point of view) which would be useful in ski-jumper's training method We have been interested in solving these problems Prom the years 1984-1992. We used the following methods: - dynamometry of the ski-jumper's take-off in natural conditions of the jumping hill in Frenstat p.R. (the length of measured platform 6 m, artificially covered jumping-hill), about 800 take-offs were analysed, - kinematic analyses of the take-off (in years 1990-1991, about450 take-offs) analysed from different jumping hills - measurement of the speed during the run-on phase, - statistical and graphical methods. Results The long term observation of these problems revealed: - a large variability of this factor in relation to different levels of performers, different forms of hill surfaces, and patterns of take-off force-time curves, - close relation of accuracy to the length of jump and other factors of the take-off, especially vigour, - t h e possibility to create a statistical model enabling the quantification of the take-off accuracy by using results from dynamometric measurements and kinematic analyses

    Human cytomegalovirus-induced host protein citrullination is crucial for viral replication

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    Citrullination is the conversion of arginine-to-citrulline by protein arginine deiminases (PADs), whose dysregulation is implicated in the pathogenesis of various types of cancers and autoimmune diseases. Consistent with the ability of human cytomegalovirus (HCMV) to induce post-translational modifications of cellular proteins to gain a survival advantage, we show that HCMV infection of primary human fibroblasts triggers PAD-mediated citrullination of several host proteins, and that this activity promotes viral fitness. Citrullinome analysis reveals significant changes in deimination levels of both cellular and viral proteins, with interferon (IFN)-inducible protein IFIT1 being among the most heavily deiminated one. As genetic depletion of IFIT1 strongly enhances HCMV growth, and in vitro IFIT1 citrullination impairs its ability to bind to 5\u27-ppp-RNA, we propose that viral-induced IFIT1 citrullination is a mechanism of HCMV evasion from host antiviral resistance. Overall, our findings point to a crucial role of citrullination in subverting cellular responses to viral infection

    Development of a Suicide Inhibition-Based Protein Labeling Strategy for Nicotinamide N-Methyltransferase

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    Nicotinamide N-methyltransferase (NNMT) catalyzes the S-adenosyl-l-methionine-dependent methylation of nicotinamide to form N-methylnicotinamide. This enzyme detoxifies xenobiotics and regulates NAD+ biosynthesis. Additionally, NNMT is overexpressed in various cancers. Herein, we describe the first NNMT-targeted suicide substrates. These compounds, which include 4-chloropyridine and 4-chloronicotinamide, exploit the broad substrate scope of NNMT; methylation of the pyridine nitrogen enhances the electrophilicity of the C4 position, thereby promoting an aromatic nucleophilic substitution by C159, a noncatalytic cysteine. On the basis of this activity, we developed a suicide inhibition-based protein labeling strategy using an alkyne-substituted 4-chloropyridine that selectively labels NNMT in vitro and in cells. In total, this study describes the first NNMT-directed activity-based probes
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