53 research outputs found

    A beginner's guide to belief revision and truth maintenance systems

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    This brief note is intended to familiarize the non-TMS audience with some of the basic ideas surrounding classic TMS's (truth maintenance systems), namely the justification-based TMS and the assumption-based TMS. Topics of further interest include the relation between non-monotonic logics and TMS's, efficiency and search issues, complexity concerns, as well as the variety of TMS systems that have surfaced in the past decade or so. These include probabilistic-based TMS systems, fuzzy TMS systems, tri-valued belief systems, and so on

    MATE: The multi-agent test environment

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    In this report we present the Multi-Agent Test Environment, MATE. MATE is a collection of experiment management tools for assisting in the design, testing, and evaluation of distributed problem-solvers. It provides the experimenter with an automated tool for executing and monitoring experiments choosing among rule bases, number of agents, communication strategies, and inference engines. Using MATE the experimenter can run a series of distributed problem-solving experiments without human intervention

    715-2 A Prospective, Randomized Trial Evaluating the Prophylactic Use of Balloon Pumping in High Risk Myocardial Infarction Patients: PAMI-2

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    Myocardial infarction (MI) patients with advanced age, multivessel disease or ventricular dysfunction continue to have a poor prognosis despite reperfusion therapy. Furthermore, the majority of deaths from MI occur within the first 48 hours, thus risk stratification and therapeutic interventions ideally should occur acutely. The PAMI-2 study has prospectively evaluated the hypotheses that 1) emergency catheterization with primary PTCA may allow acute risk stratification and 2) clinical outcome, ventricular function and infarct vessel patency will be improved by balloon pumping in patients identified to be high risk. MI patients who presented 0–12 hrs underwent emergency catheterization and PTCA and were stratified as high risk if one of the following was present: age>70 yrs, vein graft occlusion, 3 vessel disease, ejection fraction <45%, suboptimal PTCA result or if malignant arrhythmias persisted post PTCA. High risk patients were randomized to receive or not receive an intra aortic balloon pump (IABP) for 48 hrs. Catheterization was repeated at day 7 to determine infarct vessel patency and improvement in ventricular function. At 6 weeks a rest and exercise radionuclide ventriculogram was performed. To date, 320 patients have been enrolled, 175 of which have complete data available for analysis. The reasons for high risk status include: advanced age 38%, poor LV function 55%, 3 vessel disease 37%, vein graft occlusion 6%, suboptimal PTCA 9%, and arrhythmias 5%. Despite the high risk status, in-hospital outcomes have been favorable: death 2.9%, recurrent MI 5.8%, stroke 1.2%, angiographic reocclusion 5.8%, heart failure 19.1% and combined events 26.6%. Thus “high risk” patients treated with primary PTCA±balloon pumping appear to have a good prognosis. Whether the improved outcome is due to balloon pump support or simply due to aggressive mechanical revascularization will be determined in the entire cohort by March 1995

    Assessing fidelity of a community based psychosocial intervention for people with mild dementia within a large randomised controlled trial

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    Abstract: Background: Understanding intervention delivery as intended, particularly in complex interventions, should be underpinned by good quality fidelity assessment. We present the findings from a fidelity assessment embedded as part of a trial of a complex community-based psychosocial intervention, Journeying through Dementia (JtD). The intervention was designed to equip individuals with the knowledge and skills to successfully self-manage, maintain independence, and live well with dementia and involves both group and individual sessions. The methodological challenges of developing a conceptual framework for fidelity assessment and creating and applying purposely designed measures derived from this framework are discussed to inform future studies. Methods: A conceptual fidelity framework was created out of core components of the intervention (including the intervention manual and training for delivery), associated trial protocols and pre-defined fidelity standards and criteria against which intervention delivery and receipt could be measured. Fidelity data collection tools were designed and piloted for reliability and usability. Data collection in four selected sites (fidelity sites) was via non-participatory observations of the group aspect of the intervention, attendance registers and interventionist (facilitator and supervisor) self-report. Results: Interventionists from all four fidelity sites attended intervention training. The majority of group participants at the four sites (71%) received the therapeutic dose of 10 out of 16 sessions. Weekly group meeting attendance (including at ‘out of venue’ sessions) was excellent at 80%. Additionally, all but one individual session was attended by the participants who completed the intervention. It proved feasible to create tools derived from the fidelity framework to assess in-venue group aspects of this complex intervention. Results of fidelity assessment of the observed groups were good with substantial inter-rater reliability between researchers KAPPA 0.68 95% CI (0.58–0.78). Self-report by interventionists concurred with researcher assessments. Conclusions: There was good fidelity to training and delivery of the group aspect of the intervention at four sites. However, the methodological challenges of assessing all aspects of this complex intervention could not be overcome due to practicalities, assessment methods and ethical considerations. Questions remain regarding how we can assess fidelity in community-based complex interventions without impacting upon intervention or trial delivery. Trial registration: ISRCTN17993825

    The mammalian gene function resource: the International Knockout Mouse Consortium.

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    In 2007, the International Knockout Mouse Consortium (IKMC) made the ambitious promise to generate mutations in virtually every protein-coding gene of the mouse genome in a concerted worldwide action. Now, 5 years later, the IKMC members have developed high-throughput gene trapping and, in particular, gene-targeting pipelines and generated more than 17,400 mutant murine embryonic stem (ES) cell clones and more than 1,700 mutant mouse strains, most of them conditional. A common IKMC web portal (www.knockoutmouse.org) has been established, allowing easy access to this unparalleled biological resource. The IKMC materials considerably enhance functional gene annotation of the mammalian genome and will have a major impact on future biomedical research

    Diversity analysis of cotton (Gossypium hirsutum L.) germplasm using the CottonSNP63K Array

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    Cotton germplasm resources contain beneficial alleles that can be exploited to develop germplasm adapted to emerging environmental and climate conditions. Accessions and lines have traditionally been characterized based on phenotypes, but phenotypic profiles are limited by the cost, time, and space required to make visual observations and measurements. With advances in molecular genetic methods, genotypic profiles are increasingly able to identify differences among accessions due to the larger number of genetic markers that can be measured. A combination of both methods would greatly enhance our ability to characterize germplasm resources. Recent efforts have culminated in the identification of sufficient SNP markers to establish high-throughput genotyping systems, such as the CottonSNP63K array, which enables a researcher to efficiently analyze large numbers of SNP markers and obtain highly repeatable results. In the current investigation, we have utilized the SNP array for analyzing genetic diversity primarily among cotton cultivars, making comparisons to SSR-based phylogenetic analyses, and identifying loci associated with seed nutritional traits. (Résumé d'auteur
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