551 research outputs found

    An Environmental and Energy Information System

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    The Environmental Information System Office (EISO) at Oak Ridge National Laboratory (ORNL) provides information support for researchers and administrators involved with energy and environmental policy and progress. Multiple EISO activities for various governmental agencies have resulted in establishment of compatible data bases concerned with energy and environmental information, methods for effectively developing these, development and computer display of numerical data summaries, and reports evaluating published information. Direction is provided by continuing dialogue between users and information system staff

    Rapid Contingency Simulation Modeling of the NASA Crew Launch Vehicle

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    The NASA Crew Launch Vehicle is a two-stage orbital launcher designed to meet NASA's current as well as future needs for human space flight. In order to free the designers to explore more possibilities during the design phase, a need exists for the ability to quickly perform simulation on both the baseline vehicle as well as the vehicle after proposed changes due to mission planning, vehicle configuration and avionics changes, proposed new guidance and control algorithms, and any other contingencies the designers may wish to consider. Further, after the vehicle is designed and built, the need will remain for such analysis in the event of future mission planning. An easily reconfigurable, modular, nonlinear six-degree-of-freedom simulation matching NASA Marshall's in-house high-fidelity simulator is created with the ability to quickly perform simulation and analysis of the Crew Launch Vehicle throughout the entire launch profile. Simulation results are presented and discussed, and an example comparison fly-off between two candidate controllers is presented

    Embedded Relative Navigation Sensor Fusion Algorithms for Autonomous Rendezvous and Docking Missions

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    bd Systems (a subsidiary of SAIC) has developed a suite of embedded relative navigation sensor fusion algorithms to enable NASA autonomous rendezvous and docking (AR&D) missions. Translational and rotational Extended Kalman Filters (EKFs) were developed for integrating measurements based on the vehicles' orbital mechanics and high-fidelity sensor error models and provide a solution with increased accuracy and robustness relative to any single relative navigation sensor. The filters were tested tinough stand-alone covariance analysis, closed-loop testing with a high-fidelity multi-body orbital simulation, and hardware-in-the-loop (HWIL) testing in the Marshall Space Flight Center (MSFC) Flight Robotics Laboratory (FRL)

    Inferring metabolic mechanisms of interaction within a defined gut microbiota

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    The diversity and number of species present within microbial communities create the potential for a multitude of interspecies metabolic interactions. Here, we develop, apply, and experimentally test a framework for inferring metabolic mechanisms associated with interspecies interactions. We perform pairwise growth and metabolome profiling of co-cultures of strains from a model mouse microbiota. We then apply our framework to dissect emergent metabolic behaviors that occur in co-culture. Based on one of the inferences from this framework, we identify and interrogate an amino acid cross-feeding interaction and validate that the proposed interaction leads to a growth benefit in vitro. Our results reveal the type and extent of emergent metabolic behavior in microbial communities composed of gut microbes. We focus on growth-modulating interactions, but the framework can be applied to interspecies interactions that modulate any phenotype of interest within microbial communities

    Narrative language competence in children and adolescents with Down syndrome

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    This study was designed to examine the narrative language abilities of children and adolescents with Down syndrome in comparison to same-age peers with fragile X syndrome and younger typically developing children matched by nonverbal cognitive ability levels. Participants produced narrative retells from a wordless picture book. Narratives were analyzed at the macrostructural (i.e., their internal episodic structure) and the microstructural (i.e., rate of use of specific word categories) levels. Mean length of utterance, a microstructural metric of syntactic complexity, was used as a control variable. Participants with Down syndrome produced fewer episodic elements in their narratives (i.e., their narratives were less fully realized) than the typically developing participants, although mean length of utterance differences accounted for the macrostructural differences between participant groups. At the microstructural level, participants with Down syndrome displayed a lower rate of verb use than the groups with fragile X syndrome and typical development, even after accounting for mean length of utterance. These findings reflect both similarities and differences between individuals with Down syndrome or fragile X syndrome and contribute to our understanding of the language phenotype of Down syndrome. Implications for interventions to promote language development and academic achievement are discussed

    Gender Differences Concerning Physical Activity Beliefs and Practices among Fourth and Fifth Graders in Rural Virginia

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    Cardiovascular disease is the leading cause of death in the United States. Physical activity (PA) is a known preventative factor. It is recommended that children participate in 60 minutes of PA daily, but most do not meet these guidelines. Further, boys, aged 8-17 years, spend more time in PA than girls of the same age. The purposes of this study were to identify gender differences in PA beliefs and practices among fourth and fifth graders and to determine when gender disparities in self-confidence regarding PA and fitness occur.  Subjects were 41 fourth (19 boys; 22 girls) and 33 fifth (16 boys; 17 girls) graders in a public elementary school in the rural northwest. They participated in the FitnessGram, a nationwide assessment of flexibility, aerobic capacity, and muscular strength and endurance, and a proctored survey about their PA beliefs, self-confidence, and participation. There were no differences in FitnessGram data between boys and girls for aerobic capacity or muscular strength and endurance, but girls had increased flexibility when compared to boys in both grades. Importantly, survey results showed fifth grade girls had less confidence they could improve their physical fitness (p = 0.002) or their overall health (p = 0.004) when compared to fourth grade girls. Research is needed to determine how these changes in self-confidence contribute to the gender gap in time spent in PA. We recommend physical education programs throughout all grades teach healthy behaviors, including time spent in PA, and work to build and maintain self-confidence in girls

    Physical Examination is the Best Predictor of the Need for Abdominal Surgery in Children Following Motor Vehicle Collision

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    BACKGROUND: Exploratory laparotomy in children after motor vehicle collision (MVC) is rare. In the absence of definitive hemorrhage or free abdominal air on radiographic imaging, predictors for operative exploration are conflicting. OBJECTIVE: The purpose of this study was to explore objective findings that may aid in determining which children require operative abdominal exploration after MVC. METHODS: Data from 2010-2014 at an American College of Surgeons-certified level 1 pediatric trauma center were retrospectively reviewed. Demographics, vital signs, laboratory data, radiologic studies, operative records, associated injuries, and outcomes were analyzed and p < 0.05 was considered statistically significant. RESULTS: Eight hundred sixty-two patients 0-18 years of age presented to the hospital after an MVC during the study period. Seventeen patients (2.0%) required abdominal exploration and all were found to have intraabdominal injuries. Respiratory rate was the only vital sign that was significantly altered (p = 0.04) in those who required abdominal surgery compared with those who did not. Physical examination findings, such as the seat belt sign, abdominal bruising, abdominal wound, and abdominal tenderness, were present significantly more frequently in those requiring abdominal surgery (p < 0.0001). Each finding had a negative predictive value for the need for operative exploration of at least 0.98. There were no significant differences in trauma laboratory values or radiographic findings between the 2 groups. CONCLUSION: Data from this study solidify the relationship between specific physical examination findings and the need for abdominal exploration after MVC in children. In addition, these data suggest that a lack of the seat belt sign, abdominal bruising, abdominal wounds, or abdominal tenderness are individually predictive of patients who will not require surgical intervention

    Tropospheric sources and sinks of gas-phase acids in the Colorado Front Range

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    We measured organic and inorganic gas-phase acids in the Front Range of Colorado to better understand their tropospheric sources and sinks using a high-resolution time-of-flight chemical ionization mass spectrometer. Measurements were conducted from 4 to 13 August 2014 at the Boulder Atmospheric Observatory during the Front Range Air Pollution and Photochemistry Éxperiment. Diurnal increases in mixing ratios are consistent with photochemical sources of HNO3, HNCO, formic, propionic, butyric, valeric, and pyruvic acid. Vertical profiles taken on the 300&thinsp;m tower demonstrate net surface-level emissions of alkanoic acids, but net surface deposition of HNO3 and pyruvic acid. The surface-level alkanoic acid source persists through both day and night, and is thus not solely photochemical. Reactions between O3 and organic surfaces may contribute to the surface-level alkanoic acid source. Nearby traffic emissions and agricultural activity are a primary source of propionic, butyric, and valeric acids, and likely contribute photochemical precursors to HNO3 and HNCO. The combined diel and vertical profiles of the alkanoic acids and HNCO are inconsistent with dry deposition and photochemical losses being the only sinks, suggesting additional loss mechanisms.</p
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