75,696 research outputs found

    Developing people 2:evaluating the impact of training on practice

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    Phylogeny and systematics of the giant rhinoceros beetles (Scarabaeidae: Dynastini)

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    This report contains the first inclusive phylogenetic analysis and taxonomic structure for the genera presently included within the scarabaeid tribe Dynastini. The study was based upon morphological, biogeographic and molecular data and yielded direct support for the recognition of three subtribes in the Dynastini: Dynastina MacLeay, New Status (Dynastes Kirby, Augosoma Burmeister, Megasoma Kirby, Golofa Hope), Xylotrupina Hope, New Status (Xylotrupes Hope, Allomyrina Arrow, Trypoxylus Minck, Xyloscaptes Prell) and Chalcosomina Rowland and Miller, New Subtribe (Chalcosoma Hope, Haploscapanes Arrow, Beckius Dechambre, Eupatorus Burmeister, Pachyoryctes Arrow). The results provide indirect but significant support for the origin of the tribe Dynastini to be of an age no later than the early Late Cretaceous. Molecular and morphological evidence suggests that Eupatorus as constituted in current taxonomic literature is not monophyletic, and taxonomic alternatives are discussed to address this deficiency. A plausible explanation is also provided for the perplexing use by F. W. Hope of the family-group names Xylotrupidae and Dynastidae

    Tracking and data system support for the Mariner Mars 1971 mission. Volume 2: First trajectory correction maneuver through orbit insertion

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    The Deep Space Tracking and Data System activities in support of the Mariner Mars 1971 project from the first trajectory correction maneuver on 4 June 1971 through cruise and orbit insertion on 14 November 1971 are presented. Changes and updates to the TDS requirements and to the plan and configuration plus detailed information on the TDS flight support performance evaluation and the preorbital testing and training are included. With the loss of Mariner 8 at launch, a few changes to the Mariner Mars 1971 requirements, plan, and configuration were necessitated. Mariner 9 is now assuming the former mission plan of Mariner 8, including the TV mapping cycles and a 12-hr orbital period. A second trajectory correction maneuver was not required because of the accuracy of the first maneuver. All testing and training for orbital operations were completed satisfactorily and on schedule. The orbit insertion was accomplished with excellent results

    Investigation of a high speed data handling system for use with multispectral aircraft scanners

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    A buffer memory data handling technique for use with multispectral aircraft scanners is presented which allows digital data generated at high data rates to be recorded on magnetic tape. A digital memory is used to temporarily store the data for subsequent recording at slower rates during the passive time of the scan line, thereby increasing the maximum data rate recording capability over real-time recording. Three possible implementations are described and the maximum data rate capability is defined in terms of the speed capability of the key hardware components. The maximum data rates can be used to define the maximum ground resolution achievable by a multispectral aircraft scanner using conventional data handling techniques

    A note on race, ethnicity and nativity differentials in remarriage in the United States

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    The objectives of this study are to produce up-to-date estimates of race/ethnic/nativity differentials for remarriage and repartnership among women in the United States and to see if these differences are due to across-group differences in demographic characteristics. First, we produce lifetable estimates of remarriage and repartnering for white, black, U.S. born Latina and foreign born Latina women. Next, we estimate race/ethnic/nativity differentials for remarriage and repartnership using event-history analysis with and without controls for demographic characteristics. The results suggest a continued overall decline in remarriage rates, while many women repartner by cohabitating. Whites are more likely than blacks or Latinas to remarry and they are also more likely to repartner. Race/ethnic/nativity differentials remain even after accounting for variations in demographic characteristics. This suggests that race/ethnic/nativity differentials in remarriage and repartnering rates, rather than ameliorating disadvantages associated with divorce, reinforce these differentials.cohabitation, divorce, ethnicity, nativity, remarriage

    Uncoupling of p97 ATPase activity has a dominant negative effect on protein extraction

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    p97 is a highly abundant, homohexameric AAA+ ATPase that performs a variety of essential cellular functions. Characterized as a ubiquitin-selective chaperone, p97 recognizes proteins conjugated to K48-linked polyubiquitin chains and promotes their removal from chromatin and other molecular complexes. Changes in p97 expression or activity are associated with the development of cancer and several related neurodegenerative disorders. Although pathogenic p97 mutations cluster in and around p97's ATPase domains, mutant proteins display normal or elevated ATPase activity. Here, we show that one of the most common p97 mutations (R155C) retains ATPase activity, but is functionally defective. p97-R155C can be recruited to ubiquitinated substrates on chromatin, but is unable to promote substrate removal. As a result, p97-R155C acts as a dominant negative, blocking protein extraction by a similar mechanism to that observed when p97's ATPase activity is inhibited or inactivated. However, unlike ATPase-deficient proteins, p97-R155C consumes excess ATP, which can hinder high-energy processes. Together, our results shed new insight into how pathogenic mutations in p97 alter its cellular function, with implications for understanding the etiology and treatment of p97-associated diseases
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