1,007 research outputs found

    Creating Responsive Information Systems with the Help of SSADM

    Get PDF
    In this paper, a program for a research is outlined. Firstly, the concept of responsive information systems is defined and then the notion of the capacity planning and software performance engineering is clarified. Secondly, the purpose of the proposed methodology of capacity planning, the interface to information systems analysis and development methodologies (SSADM), the advantage of knowledge-based approach is discussed. The interfaces to CASE tools more precisely to data dictionaries or repositories (IRDS) are examined in the context of a certain systems analysis and design methodology (e.g. SSADM)

    NASA/ESA CV-990 Spacelab Simulation (ASSESS 2)

    Get PDF
    To test the validity of the ARC approach to Spacelab, several missions simulating aspects of Spacelab operations have been conducted as part of the ASSESS Program. Each mission was designed to evaluate potential Shuttle/Spacelab concepts in increasing detail. For this mission, emphasis was placed on development and exercise of management techniques planned for Spacelab using management participants from NASA and ESA who have responsibilities for Spacelab 1 which will be launched in 1980

    IRD dropout study

    Get PDF
    This final report describes work performed by SRS Technologies for the NASA Marshall Space Flight Center under Contract NAS8-39077, entitled 'Integrated Receiver-Decoder Dropout Study'. The purpose of the study was to determine causes of signal fading effects on ultra-high-frequency (UHF) range safety transmissions to the Space Shuttle during flyout. Of particular interest were deep fades observed at the External Tank (ET) Integrated Receiver-Decoder (IRD) during the flyout interval between solid rocket booster separation and ET separation. Analytical and simulation methods were employed in this study to assess observations captured in flight telemetry data records. Conclusions based on the study are presented in this report, and recommendations are given for future experimental validation of the results

    Optical genome mapping and revisiting short-read genome sequencing data reveal previously overlooked structural variants disrupting retinal disease-associated genes

    Full text link
    Purpose: Structural variants (SVs) play an important role in inherited retinal diseases (IRD). Although the identification of SVs significantly improved upon the availability of genome sequencing, it is expected that involvement of SVs in IRDs is higher than anticipated. We revisited short-read genome sequencing data to enhance the identification of gene-disruptive SVs. Methods: Optical genome mapping was performed to improve SV detection in short-read genome sequencing-negative cases. In addition, reanalysis of short-read genome sequencing data was performed to improve the interpretation of SVs and to re-establish SV prioritization criteria. Results: In a monoallelic USH2A case, optical genome mapping identified a pericentric inversion (173 megabase), with 1 breakpoint disrupting USH2A. Retrospectively, the variant could be observed in genome sequencing data but was previously deemed false positive. Reanalysis of short-read genome sequencing data (427 IRD cases) was performed which yielded 30 pathogenic SVs affecting, among other genes, USH2A (n = 15), PRPF31 (n = 3), and EYS (n = 2). Eight of these (>25%) were overlooked during previous analyses. Conclusion: Critical evaluation of our findings allowed us to re-establish and improve our SV prioritization and interpretation guidelines, which will prevent missing pathogenic events in future analyses. Our data suggest that more attention should be paid to SV interpretation and the current contribution of SVs in IRDs is still underestimated

    Integrating plug-in electric vehicles into the electric power system

    Get PDF
    This dissertation contributes to our understanding of how plug-in hybrid electric vehicles (PHEVs) and plug-in battery-only electric vehicles (EVs)—collectively termed plug-in electric vehicles (PEVs)—could be successfully integrated with the electric power system. The research addresses issues at a diverse range of levels pertaining to light-duty vehicles, which account for the majority of highway vehicle miles traveled, energy consumed by highway travel modes, and carbon dioxide emissions from on-road sources. Specifically, the following topics are investigated: (i) On-board power electronics topologies for bidirectional vehicle-to-grid and grid-to-vehicle power transfer; (ii) The estimation of the electric energy and power consumption by fleets of light-duty PEVs; (iii) An operating framework for the scheduling and dispatch of electric power by PEV aggregators; (iv) The pricing of electricity by PHEV aggregators and how it affects the decision-making process of a cost-conscious PHEV owner; (v) The impacts on distribution systems from PEVs under aggregator control; (vi) The modeling of light-duty PEVs for long-term energy and transportation planning at a national scale

    Genetic analysis of inherited retinal diseases in indigenous Southern African populations

    Get PDF
    Background: Inherited retinal diseases (IRDs) constitute a group of clinically and genetically heterogeneous conditions which cause degeneration of retinal photoreceptor cells and result in visual impairment. Characterisation of the genetic basis of IRD is not only beneficial for the affected families, but also contributes towards understanding of the disease pathobiology. Investigations into the molecular basis of IRDs have been ongoing in South Africa (SA) for over 30 years, however the evaluation of reported genetic mutations has yielded low returns in certain populations. Indigenous southern Africans comprise a unique population group with distinct genetic diversity, providing a valuable resource for genetic discoveries; nonetheless, this population remains largely underrepresented in genomic studies. The aim of this investigation was to characterise the underlying genetic mutations in a cohort of indigenous African IRD patients. Methods: The IRD registry in the Division of Human Genetics (University of Cape Town) was reviewed for causative mutations. Subsequently, upon identifying a mutation underlying Usher Syndrome in two indigenous African patients, an assay was designed to screen for this mutation in probands with different IRDs (n=170) and controls (n=51), and haplotype analysis was performed on mutation-positive individuals. The registry review additionally served to identify a suitable cohort for the application of next generation sequencing (NGS) technology. Whole exome sequencing (WES) was performed on genomic DNA samples from 56 individuals from 16 families. The WES data analysis strategy involved prioritisation of variants in reported and candidate IRD genes. Rare, co-segregating, pathogenic, exonic or splice variants were validated by Sanger sequencing. Custom TaqMan assays were designed to screen seven mutations, identified by WES, in 193 unrelated indigenous African probands with IRDs. Results: A homozygous founder mutation, c.6377delC in MYO7A, was identified in 43% of the indigenous African patients with Usher syndrome, which is the most common cause of deaf-blindness. Targeted WES data analysis of all known IRD genes resulted in identification of the underlying genetic defects in six distinct genes (RHO, PRPF3, PRPF31, ABCA4, CERKL, and PDE6B) in six families. Taqman screening revealed four additional probands with identical homozygous mutations in CERKL and PDE6B. An X-linked gene (RP2) mutation was subsequently identified in an affected family with semi-dominant retinitis pigmentosa. Supplementary analysis of the X-linked RPGR ORF15 mutation hotspot (not adequately covered by WES) identified two mutations in three families. A novel IRD gene, IDH3A, was found in one family by analysis of 22 putative candidate genes. The large number of variants in the remainder of the indigenous African exomes presented considerable challenges for identification of additional novel genes. Discussion: The results of this project have important implications for IRD molecular diagnostic services in SA. Using WES, a genetic diagnosis was obtained for ±73% of the indigenous African cohort, and ±70% of the causative mutations identified were novel. This outcome emphasises the superiority of NGS-based approaches over genotyping-based microarrays which screen for IRD mutations previously reported in other (mainly European-derived) populations. The unexpected identification of mutations in known X-linked genes in four families highlighted key considerations for IRD WES analysis. Cascade screening of mutations identified in this study, across larger cohorts of unrelated probands, revealed the genetic cause of IRD in additional cases and the number of indigenous African families in the registry with a genetic diagnosis was effectively doubled. Members of these families can now opt for diagnostic, carrier, or predictive testing of familial mutations. Finally, the information obtained from this research contributes towards a better understanding of the genetic architecture of IRDs in SA

    NASA/ESA CV-990 Spacelab Simulation (ASSESS 2)

    Get PDF
    Cost effective techniques for addressing management and operational activities on Spacelab were identified and analyzed during a ten day NASA-ESA cooperative mission with payload and flight responsibilities handled by the organization assigned for early Spacelabs. Topics discussed include: (1) management concepts and interface relationships; (2) experiment selection; (3) hardware development; (4) payload integration and checkout; (5) selection and training of mission specialists and payload specialists; (6) mission control center/payload operations control center interactions with ground and flight problems; (7) real time interaction during flight between principal investigators and the mission specialist/payload specialist flight crew; and (8) retrieval of scientific data and its analysis

    Knowledge is power: student-driven strategies for success in Alaska's challenging postsecondary context

    Get PDF
    Master's Project (M.A.) University of Alaska Fairbanks, 201

    Implementation science approaches to family planning and reproductive health: Experiential learning and sharing for implementers, policy-makers, researchers, and advocates

    Get PDF
    This is a report on a workshop funded by the United States Agency for International Development (USAID) through the Evidence Project, in collaboration with the TRAction Project. This interactive half-day session provided participants with practical examples of how implementation science (IS) can inform programming and policies related to family planning and reproductive health. Presentations, case studies, and group discussions sought to address the following questions: 1) What are the benefits and challenges or limitations of an IS approach to family planning/reproductive health programming? 2) What is the relationship between evidence and advocacy? 3) How can evidence be best utilized to inform the scale-up of programming and best practices? and 4) How can we engage stakeholders and build institutional capacity to leverage IS approaches

    Brugia Pahangi: Effects of Maternal Filariasis on the Responses of Their Progeny to Homologous Infection.

    Get PDF
    The effects of in utero and neonatal exposure to maternal Brugia pahangi infections on the development of homologous infections, immune responses, and pathologic lesions was studied in age-matched progeny of infected and uninfected female jirds. High IgG antibody titers to B. pahangi antigens were present in the sera of progeny from infected mothers. These neonatal titers to homologous antigens were shown to be of maternal origin, and did not alter the cellular responses of uninfected progeny as measured by in vitro antigen-stimulated blastogenesis and in vivo pulmonary granulomatous inflammatory responses to antigen-coated beads. Studies were conducted to measure age-related differences in susceptibility, lymphatic lesion formation, and antibody responses to B. pahangi infection in 2−-, 6−-, 10−-, and 15-week old jirds from uninfected mothers. Significant reductions in quantities of testicular and intralymphatic worms recovered and antibody responses to solbule antigens in jirds infected at 2 weeks of age had no measurable effect on susceptibility or lymphatic lesion severity expressed as the ratio of intralymphatic thrombi formed per intralymphatic worm. Challenge infections in 2- or 4-week old progeny from B. pahangi-infected and uninfected female jirds yielded equivalent adult worm recoveries and microfilaremias. Lymphatic lesion severity expressed as the ratio of intralymphatic thrombi formed per intralymphatic worm recovered was similar in all groups. Offspring infected at either 2 or 4 weeks of age from infected mothers exhibited significantly lower serum IgG antibody titers to B. pahangi antigens compared to infected progeny of uninfected mothers at 5-8 weeks postinfection. Infected offspring from infected mothers displayed significantly fewer antigen-specific splenic plague-forming cells at 5 weeks postinfection than infected control progeny. Qualitative and quantitative reductions in serum antibody reactivity to B. pahangi antigens were also demonstrated by Western immunoblot at 8 weeks postinfection in infected progeny of infected females. These results suggest that a partial immune tolerance to B. pahangi antigens develops in infected offspring of infected female jirds. These modulated antibody responses had no measurable effect on the establishment of adult worms, microfilaremias, lymphatic lesion development, or antigen-specific pulmonary granulomatous inflammatory responses
    • …
    corecore