2,585 research outputs found

    Test and evaluation of load converter topologies used in the Space Station Freedom Power Management and distribution DC test bed

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    Power components hardware in support of the Space Station Freedom dc Electrical Power System were tested. One type of breadboard hardware tested is the dc Load Converter Unit, which constitutes the power interface between the electric power system and the actual load. These units are dc to dc converters that provide the final system regulation before power is delivered to the load. Three load converters were tested: a series resonant converter, a series inductor switchmode converter, and a switching full-bridge forward converter. The topology, operation principles, and tests results are described, in general. A comparative analysis of the three units is given with respect to efficiency, regulation, short circuit behavior (protection), and transient characteristics

    A reappraisal of the morphology and systematic position of the theropod dinosaur Sigilmassasaurus from the "middle" Cretaceous of Morocco

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    Sigilmassasaurus brevicollis is an enigmatic theropod dinosaur from the early Late Cretaceous (Cenomanian) of Morocco, originally based on a few isolated cervical vertebrae. Ever since its original description, both its taxonomic validity and systematic affinities were contentious. Originally considered to represent its own family, Sigilmassasauridae, the genus has variously been suggested to represent a carcharodontosaurid, an ornithischian, and, more recently, a spinosaurid. Here we describe new remains referrable to this taxon and re-evaluate its taxonomic status and systematic affinities. Based on the new remains, a re-evaluation of the original materials, and comparisons with other spinosaurids, the holotype of Sigilmassasaurus brevicollis is identified as an anterior dorsal, rather than a cervical vertebra, and differences between elements referred to this taxon can be explained by different positions of the elements in question within the vertebral column. Many characters used previously to diagnose the genus and species are found to be more widespread among basal tetanurans, and specifically spinosaurids. However, the taxon shows several autapomorphies that support its validity, including the presence of a strongly rugose, ventrally offset triangular platform that is confluent with a ventral keel anteriorly in the mid-cervical vertebral centra and a strongly reduced lateral neural arch lamination, with no or an incomplete distinction between anterior and posterior centrodiapophyseal laminae in the posterior cervical and anterior dorsal vertebrae. We argue furthermore that Spinosaurus maroccanus, also described on the basis of isolated cervical vertebrae from the same stratigraphic unit and in the same paper as Sigilmassasaurus brevicollis, is a subjective synonym of the latter. Both a detailed comparison of this taxon with other theropods and a formal phylogenetic analysis support spinosaurid affintities for Sigilmassasaurus. However, we reject the recently proposed synonymy of both Spinosaurus maroccanus and Sigilmassasurus brevicollis with Spinosaurus aegyptiacus from the Cenomanian of Egypt, as there are clear differences between the vertebrae of these taxa, and they do not share any derived character that is not found in other spinosaurids. Together with a comparison with other spinosaurid vertebral material from the Kem Kem, this suggests that more than one taxon of spinosaurid was present in the Kem Kem assemblage of Morocco, so the referral of non-overlapping material from this unit to a single taxon should be regarded with caution

    Commercial and Property Law Textbooks Collections: Accreditation Issues and Imperatives for Law Libraries

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    Investigations into the development of commercial and property law textbooks (local and foreign) collections, an accreditation requirement in the South East Universities in relation to the Council of Legal Education standards were carried out.  The scope consists of 98 titles of local and foreign commercial and property law textbooks listed by Council of Legal Education as accreditation bench mark and involves seven law faculty libraries in the universities South East Geopolitical zone of Nigeria that offer law programme. The areas covered include Company Law and Practices, Law of Insurance, Business Law and Banking, Taxation Law, Copyrights Law and Land/Property Law. The instrument for data collection was the standard check list released by Council of Legal Education.  This check list was found appropriate and adopted for this study.  Two research questions were formulated for the study.  The findings revealed that only NnamdiAzikiwe University law library in the zone met the Council of Legal Education accreditation standards in Law of Insurance in commercial law textbooks collections.  Recommendations were made which include among others the need for periodic assessment of collections, constant review and revision of the list. Keywords: Law Library, library collections, accreditation, commercial law, property Law standards

    The C-Band All-Sky Survey: Instrument design, status, and first-look data

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    The C-Band All-Sky Survey (C-BASS) aims to produce sensitive, all-sky maps of diffuse Galactic emission at 5 GHz in total intensity and linear polarization. These maps will be used (with other surveys) to separate the several astrophysical components contributing to microwave emission, and in particular will allow an accurate map of synchrotron emission to be produced for the subtraction of foregrounds from measurements of the polarized Cosmic Microwave Background. We describe the design of the analog instrument, the optics of our 6.1 m dish at the Owens Valley Radio Observatory, the status of observations, and first-look data.Comment: 10 pages, 11 figures, published in Proceedings of SPIE MIllimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V (2010), Vol. 7741, 77411I-1 - 77411I-1

    Global analysis of differential gene expression within the porcine conceptus transcriptome as it transitions through spherical, ovoid, and tubular morphologies during the initiation of elongation

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    This study aimed to identify transcriptome differences between distinct or transitional stage spherical, ovoid, and tubular porcine blastocysts throughout the initiation of elongation. We performed a global transcriptome analysis of differential gene expression using RNA‐Seq with high temporal resolution between spherical, ovoid, and tubular stage blastocysts at specific sequential stages of development from litters containing conceptus populations of distinct or transitional blastocysts. After RNA‐Seq analysis, significant differentially expressed genes (DEGs) and pathways were identified between distinct morphologies or sequential development stages. Overall, 1898 significant DEGs were identified between distinct spherical and ovoid morphologies, with 311 total DEGs between developmental stages throughout this first morphological transition, while 15 were identified between distinct ovoid and tubular, with eight total throughout these second morphological transition developmental stages. The high quantity of DEGs and pathways between conceptus stages throughout the spherical to ovoid transition suggests the importance of gene regulation during this first morphological transition for initiating elongation. Further, extensive DEG coverage of known elongation signaling pathways was illustrated from spherical to ovoid, and regulation of lipid signaling and membrane/ECM remodeling across these early conceptus stages were implicated as essential to this process, providing novel insights into potential mechanisms governing this rapid morphological change

    Development and validation of a prognostic model for death 30 days after adult emergency laparotomy

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    The probability of death after emergency laparotomy varies greatly between patients. Accurate pre-operative risk prediction is fundamental to planning care and improving outcomes. We aimed to develop a model limited to a few pre-operative factors that performed well irrespective of surgical indication: obstruction; sepsis; ischaemia; bleeding; and other. We derived a model with data from the National Emergency Laparotomy Audit for patients who had emergency laparotomy between December 2016 and November 2018. We tested the model on patients who underwent emergency laparotomy between December 2018 and November 2019. There were 4077/40,816 (10%) deaths 30 days after surgery in the derivation cohort. The final model had 13 pre-operative variables: surgical indication; age; blood pressure; heart rate; respiratory history; urgency; biochemical markers; anticipated malignancy; anticipated peritoneal soiling; and ASA physical status. The predicted mortality probability deciles ranged from 0.1% to 47%. There were 1888/11,187 deaths in the test cohort. The scaled Brier score, integrated calibration index and concordance for the model were 20%, 0.006 and 0.86, respectively. Model metrics were similar for the five surgical indications. In conclusion, we think that this prognostic model is suitable to support decision-making before emergency laparotomy as well as for risk adjustment for comparing organisations

    Outbreak investigation including molecular characterization of community associated methicillin-resistant Staphylococcus aureus in a primary and secondary school in Eastern Switzerland

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    At our tertiary children's hospital, infections with newly detected methicillin-resistant Staphylococcus aureus (MRSA) among children attending primary (age 6-12 years) and secondary school (age 13-16 years) nearly doubled in 2018 compared to previous years. This observation initiated an epidemiological outbreak investigation including phenotypic (susceptibility testing) and genotypic (whole genome sequencing) characterization of the isolates. In addition, a cross-sectional study was conducted to determine source of the outbreak, colonization frequency and to identify risk factors for transmission using a questionnaire. As a result, 49 individuals were detected with 57 corresponding isolates. Based on the case definition combined with whole genome sequencing, a core cluster was identified that shared common genetic features and a similar antimicrobial susceptibility pattern (efflux-mediated macrolide resistance, tetracycline susceptibility along with presence of Panton-Valentine leukocidin). Epidemiologic evaluation identified a distinct school as a common risk factor. However, the source of the clustered infections within that school could not be further specified. No further cases could be detected after decolonization of infected and colonized children

    Mediterranean diet adherence and cognitive function in older, UK adults: The EPIC-Norfolk study

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    Background In Mediterranean countries, adherence to a traditional Mediterranean dietary pattern (MedDiet) is associated with better cognitive function and reduced dementia risk. It is unclear if similar benefits exist in non-Mediterranean regions. Objective To examine associations between MedDiet adherence and cognitive function in an older, UK population. To investigate whether associations differed between individuals with high versus low cardiovascular disease (CVD) risk. Design We conducted an analysis in 8009 older individuals with dietary data at Health Check 1 (1993-1997) and cognitive function data at Health Check 3 (2006-2011) of the European Prospective Investigation of Cancer, Norfolk (EPIC-Norfolk). Associations were explored between MedDiet adherence and global and domain specific cognitive test scores and risk of poor cognitive performance in the entire cohort, and when stratified according to CVD risk status. Results Higher MedDiet adherence defined by the Pyramid MedDiet score was associated with better global cognition (β±SE=-0.012±0.002; P<0.001), verbal episodic memory (β±SE=-0.009±0.002; P<0.001), and simple processing speed (β±SE=-0.002±0.001; P=0.013). Lower risk of poor verbal episodic memory (OR(95%CI)=0.784 (0.641,0.959); P=0.018), complex processing speed (OR(95%CI)=0.739 (0.601,0.907); P=0.004), and prospective memory (OR(95%CI)=0.841 (0.724,0.977); P=0.023) was also observed for the highest versus lowest Pyramid MedDiet tertiles. The effect of a one-point increase in Pyramid score on global cognitive function was equivalent to 1.7 fewer years of cognitive ageing. MedDiet adherence defined by the MEDAS score (mapped using both binary and continuous scoring) showed similar, albeit less consistent, associations. In stratified analyses, associations were evident in individuals at higher CVD risk only (P<0.05). Conclusions Higher adherence to the MedDiet is associated with better cognitive function and lower risk of poor cognition in older, UK adults. This evidence underpins the development of interventions to enhance MedDiet adherence, particularly in individuals at higher CVD risk, aiming to reduce the risk of age-related cognitive decline in non-Mediterranean populations
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