4,434 research outputs found

    Dynamic Characteristics and Stability Analysis of Space Shuttle Main Engine Oxygen Pump

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    The dynamic characteristics of the Space Shuttle high pressure oxygen pump are presented. Experimental data is presented to show the vibration spectrum and response under actual engine operation and also in spin pit testing for balancing. The oxygen pump appears to be operating near a second critical speed and is sensitive to self excited aerodynamic cross coupling forces in the turbine and pump. An analysis is presented to show the improvement in pump stability by the application of turbulent flow seals, preburner seals, and pump shaft cross sectional modifications

    A TWO-STAGE MODEL OF THE DEMAND FOR SPECIALTY CROP INSURANCE

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    Legislators are considering raising catastrophic (CAT 50% coverage) crop insurance premiums. However, estimates of a two-stage coverage-choice and participation model using county-level data from California grape growers show that the demand for CAT insurance is price-elastic, therefore, premium increases will worsen the financial performance of the grape-insurance program.crop insurance, discrete / continuous choice, grapes, multinomial logit, Research Methods/ Statistical Methods, Risk and Uncertainty,

    Stories as personal coaching philosophy

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    The importance of coaches developing and articulating a personal coaching philosophy which encapsulates their values and beliefs is widely recognised. Yet it is also acknowledged that many coaches resist what appears an abstract task or find it to be of limited use in their day-to-day practice. In this paper we explore the potential of an alternative approach to developing and articulating a personal coaching philosophy: storytelling. Following a discussion of the potential of stories, we present a story written by one coach which expresses her personal philosophy in a way that is firmly rooted in her coaching practice. Storytelling approaches, we suggest, can reveal the connections between abstract/general philosophy and the personal embodied experience of coaching. We reflect on the possibilities and problems of using stories as philosophy and offer some suggestions for how coaches may be supported in developing their coaching philosophy through storytelling

    A computer program for a line-by-line calculation of spectra from diatomic molecules and atoms assuming a Voight line profile

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    Computer program predicts the spectra resulting from electronic transitions of diatomic molecules and atoms in local thermodynamic equilibrium. The program produces a spectrum by accounting for the contribution of each rotational and atomic line considered

    Method of identifying clusters representing statistical dependencies in multivariate data

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    Approach is first to cluster and then to compute spatial boundaries for resulting clusters. Next step is to compute, from set of Monte Carlo samples obtained from scrambled data, estimates of probabilities of obtaining at least as many points within boundaries as were actually observed in original data

    Getting it right for everyone : Sport coaching and the adult participation domain

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    Sport provision is best understood as a series of distinctive domains, with characteristic purposes, motivations, practices and demands on coaches’ expertise. This paper identifies the characteristics of the instructor-led adult participation coaching domain, which is the least well researched and developed, and identifies the implications for coach education and workforce management. The propositions are illustrated by conversations with Coaching Development Managers from 8 sports in the UK that have a significant adult participation profile. The paper confirms the variety of domain populations, from casual recreation to coach-dependent adult competition, including ‘Masters’-designated participation, but outside the mainstream of performance sport. It highlights two principal coaching practices: market-led sport instructors, delivering episodic, largely technique-based ‘lessons’ to participants, and (club) coaches of adult competition sport. However, much of the characteristic adult participation is casual recreation and coach-independent. The paper argues that a fuller understanding of this domain is important for ensuring that coaches’ expertise and practice are matched to participant needs

    Not Congruent but Quite Complementary: U.S. and Chinese Approaches to Nontraditional Security

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    U.S.-China relations, difficult in the best of times, have lurched in a dangerous direction since 2009. Against the backdrop of a weakened global economy and sharpened ideological tensions, there has been a disturbing new atmosphere of crisis in East Asia over the last two years, with incidents occurring in greater frequency and sowing serious doubts about the sustainability of the long peace that this region has enjoyed for decades. Indeed, any one of the following incidents could have escalated into a serious regional crisis: the sinking of the South Korean frigate Cheonan; the collision between a Japanese coast guard cutter and a Chinese fishing trawler and the ensuing Chinese restrictions on the export of rare-earth minerals; and a string of confrontations between Chinese patrol ships and vessels from both Vietnam and the Philippines.https://digital-commons.usnwc.edu/cmsi-red-books/1008/thumbnail.jp

    Quantification of Conformational Heterogeneity and its Role in Protein Aggregation and Unfolding

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    Proteins can exhibit significant conformational heterogeneity either under denaturing conditions or in aqueous solutions. The latter is true for a class of proteins whose sequences predispose them to form heterogeneous ensembles of conformations. Characterization of conformational heterogeneity in a protein ensemble requires the quantification of the amplitudes of spontaneous fluctuations in conjunction with information regarding coarse grain measures that report on the average sizes, shapes, and densities. This often demands multiplexed experimental approaches whose readouts are interpreted or annotated using ensembles drawn from atomistic or coarse grain computational simulations. Efforts to characterize conformational heterogeneity contribute directly to our understanding of disorder-to-order transitions in protein folding and self-assembly. These efforts are also crucial to our understanding of the heterotypic interactions involving intrinsically disordered proteins and non-native states of well-folded proteins. These heterotypic interactions are important in signal transduction and the regulation of protein homeostasis. The onset and progression of several systemic and neurodegenerative conformational diseases are linked to the nature and degree of conformational heterogeneity in specific proteins or proteolytic products of proteins. This thesis work focuses on the quantitative characterization of conformational heterogeneity in simulated ensembles of inducibly unfolded and intrinsically disordered proteins. Advances in nuclear magnetic resonance spectroscopy afford the possibility of detailed measurements of inter-residue distances and modulations to the relaxation dynamics of paramagnetic spins that are inserted as probes into a protein. These state-of-the-art measurements show interesting features within denatured state ensembles that cannot be explained using canonical random coil models. Here, we use computer simulations to generate plausible facsimiles of denatured state ensembles that reproduce experimental data and demonstrate that the ensembles that are consistent with the data are characterized by the presence of low-likelihood, long-range intra-chain contacts between hydrophobic groups. When placed in the context of sequence conservation information, it appears that these contacts act as gatekeepers that protect proteins from the deleterious consequences of protein aggregation by sequestering hydrophobic groups in an assortment of intra-chain long-range contacts. We also characterize the nature and degree of conformational heterogeneity in glutamine- and asparagine-rich containing systems. These efforts lead to insights regarding the role of conformational heterogeneity in mediating intermolecular associations that are implicated in aggregation and self-assembly of these systems. Analysis of results from atomistic simulations leads to a phenomenological model for the modulation of conformational heterogeneity and degeneracies of intermolecular interactions by naturally occurring sequences that flank polyglutamine domains. Finally, we develop a formal order parameter to quantify the conformational heterogeneity in simulated ensembles of proteins. When combined with measures of density and fluctuations thereof, it can be used to provide a complete description of the degree and nature of conformational heterogeneity in different ensembles, thus affording the ability to compare different ensembles to each other while also providing a way to categorize conformational transitions
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