1,364 research outputs found

    A failure recovery planning prototype for Space Station Freedom

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    NASA is investigating the use of advanced automation to enhance crew productivity for Space Station Freedom in numerous areas, including failure management. A prototype is described that uses various advanced automation techniques to generate courses of action whose intents are to recover from a diagnosed failure, and to do so within the constraints levied by the failure and by Freedom's configuration and operating conditions

    Process and information integration via hypermedia

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    Success stories for advanced automation prototypes abound in the literature but the deployments of practical large systems are few in number. There are several factors that militate against the maturation of such prototypes into products. Here, the integration of advanced automation software into large systems is discussed. Advanced automation systems tend to be specific applications that need to be integrated and aggregated into larger systems. Systems integration can be achieved by providing expert user-developers with verified tools to efficiently create small systems that interface to large systems through standard interfaces. The use of hypermedia as such a tool in the context of the ground control centers that support Shuttle and space station operations is explored. Hypermedia can be an integrating platform for data, conventional software, and advanced automation software, enabling data integration through the display of diverse types of information and through the creation of associative links between chunks of information. Further, hypermedia enables process integration through graphical invoking of system functions. Through analysis and examples, researchers illustrate how diverse information and processing paradigms can be integrated into a single software platform

    A failure management prototype: DR/Rx

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    This failure management prototype performs failure diagnosis and recovery management of hierarchical, distributed systems. The prototype, which evolved from a series of previous prototypes following a spiral model for development, focuses on two functions: (1) the diagnostic reasoner (DR) performs integrated failure diagnosis in distributed systems; and (2) the recovery expert (Rx) develops plans to recover from the failure. Issues related to expert system prototype design and the previous history of this prototype are discussed. The architecture of the current prototype is described in terms of the knowledge representation and functionality of its components

    Long-Term Trends in Calcifying Plankton and pH in the North Sea

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    Relationships between six calcifying plankton groups and pH are explored in a highly biologically productive and data-rich area of the central North Sea using time-series datasets. The long-term trends show that abundances of foraminiferans, coccolithophores, and echinoderm larvae have risen over the last few decades while the abundances of bivalves and pteropods have declined. Despite good coverage of pH data for the study area there is uncertainty over the quality of this historical dataset; pH appears to have been declining since the mid 1990s but there was no statistical connection between the abundance of the calcifying plankton and the pH trends. If there are any effects of pH on calcifying plankton in the North Sea they appear to be masked by the combined effects of other climatic (e.g. temperature), chemical (nutrient concentrations) and biotic (predation) drivers. Certain calcified plankton have proliferated in the central North Sea, and are tolerant of changes in pH that have occurred since the 1950s but bivalve larvae and pteropods have declined. An improved monitoring programme is required as ocean acidification may be occurring at a rate that will exceed the environmental niches of numerous planktonic taxa, testing their capacities for acclimation and genetic adaptation

    Maternal Depression, Paternal Psychopathology, and Adolescent Diagnostic Outcomes

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    The authors examined the relationship between maternal depression, paternal psychopathology, and adolescent diagnostic outcomes in a community sample of 522 Australian families. They also examined whether chronic family stress, father's expressed emotion, and parents' marital satisfaction mediated the relationship between parental psychopathology and adolescent outcomes. Mother's education, child's gender, and family income were covaried in all analyses. Results revealed that maternal depression and paternal depression had an additive effect on youth externalizing disorders. In addition, maternal depression interacted with both paternal depression and paternal substance abuse in predicting youth depression but not youth nondepressive disorders. Chronic family stress and father's expressed emotion appeared to mediate the relationship between parental psychopathology and youth depression

    Daily stress reactivity and serotonin transporter gene (5-HTTLPR) variation: internalizing responses to everyday stress as a possible transdiagnostic phenotype

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    BACKGROUND: Recent studies examining the interaction between the 5-HTTLPR locus in the serotonin transporter gene and life stress in predicting depression have yielded equivocal results, leading some researchers to question whether 5-HTTLPR variation indeed regulates depressive responses to stress. Two possible sources of inconsistent data in this literature are imprecise stress assessment methodologies and a restricted focus on depression phenotypes as the outcome of interest, as opposed to transdiagnostic emotional symptoms such as internalizing and externalizing dimensions. The present study aimed to address these critical limitations in prior research by examining how 5-HTTLPR acts in concert with idiographically assessed daily life stress to predict transdiagnostic emotional outcomes. RESULTS: One hundred and four healthy young adults genotyped for 5-HTTLPR reported on their life stress exposure and internalizing and externalizing experiences for 14 consecutive days. As hypothesized, daily stress levels were associated with severity of internalizing symptoms, but only for 5-HTTLPR S allele carriers. Additional analyses revealed that these interactive effects of 5-HTTLPR and daily life stress on internalizing symptoms extended to both the distress and fear subdomains of internalizing symptoms. CONCLUSIONS: Considered together, these results support the validity of the 5-HTTLPR stress sensitivity hypothesis and suggest for the first time that variation at 5-HTTLPR moderates the effects of daily life stress on broadband symptom profiles

    Habitat associations of shovelnose sturgeon \u3ci\u3eScaphirhynchus platorynchus\u3c/i\u3e (Rafinesque, 1820) in the lower Platte River, Nebraska

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    Human induced alterations of river systems are ubiquitous throughout the world. Alterations have reduced riverine habitat and negatively affected riverine species; therefore, it is crucial to understand what habitats are important to riverine fish at multiple scales. Most research has focused around microhabitats (i.e., depth) with little effort on how the reach scale habitat (i.e., geomorphic landscape) influences riverine fish abundance. We examined habitat associations of shovelnose sturgeon sampled with two gears (trotlines and trammel nets) at multiple spatial scales in the lower Platte River, NE, a system that has not been overtly altered in physical description. At a microhabitat scale, shovelnose sturgeon abundance was influenced by velocities and temperatures within the lower Platte River. The influence of velocity was contradictory between gears suggesting that gear limitations may have been present. Shovelnose sturgeon abundance increased in close proximity to a tributary interaction with the lower Platte River in both gears. Portions of the river with a relatively medium valley width, low-medium sinuosity, and wide channel had the lowest shovelnose sturgeon abundance for both gears. Our results provide insight at multiple habitat scales on the landscape that may help managers and policy makers develop sound approaches to protecting and mitigating habitat for shovelnose sturgeon and other riverine species

    Functional MRI in Patients with Band Heterotopia

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    Functional activation associated with a motor task (fist movements) was studied in three patients with band heterotopias by fMRI. In two patients, additional visual fMRI studies were performed using a flickering checkerboard stimulus. In all patients activation of the outer cortex and of the inner neuronal band could be found during performance of the motor task. Visual stimulation elicited a normal activation pattern without activation of the ectopic neuronal layer in one patient; in another patient activation extended toward the ventricular wall, i.e., along the route of embryonic neuronal migration. The potential participation of ectopic neuronal tissue in physiologic cerebral functions is of clinical impact in patients with neuronal heterotopias suffering from medically intractable seizures prior to epilepsy surgery
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