6,317 research outputs found

    Chris Christie

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    Astromaterials Curation Online Resources for Principal Investigators

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    The Astromaterials Acquisition and Curation office at NASA Johnson Space Center curates all of NASA's extraterrestrial samples, the most extensive set of astromaterials samples available to the research community worldwide. The office allocates ~1500 individual samples to researchers and students each year and has served the planetary research community for 45+ years. The Astromaterials Curation office provides access to its sample data repository and digital resources to support the research needs of sample investigators and to aid in the selection and request of samples for scientific study. These resources can be found on the Astromaterials Acquisition and Curation website at https://curator.jsc.nasa.gov. To better serve our users, we have engaged in several activities to enhance the data available for astromaterials samples, to improve the accessibility and performance of the website, and to address user feedback. We havealso put plans in place for continuing improvements to our existing data products

    A Bound on the Energy Loss of Partons in Nuclei

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    We derive a quantum mechanical upper bound on the amount of radiative energy loss suffered by high energy quarks and gluons in nuclear matter. The bound shows that the nuclear suppression observed in quarkonium production at high xFx_F cannot be explained in terms of energy loss of the initial or final parton states. We also argue that no nuclear suppression is expected in the photoproduction of light hadrons at large xFx_F.Comment: 15 pages, 1 figure included as a Postscript file, phyzzx.te

    Transverse instability of plane wave soliton solutions of the Novikov-Veselov equation

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    The Novikov-Veselov (NV) equation is a dispersive (2+1)-dimensional nonlinear evolution equation that generalizes the (1+1)-dimensional Korteweg-deVries (KdV) equation. This paper considers the stability of plane wave soliton solutions of the NV equation to transverse perturbations. To investigate the behavior of the perturbations, a hybrid semi-implicit/spectral numerical scheme was developed, applicable to other nonlinear PDE systems. Numerical simulations of the evolution of transversely perturbed plane wave solutions are presented. In particular, it is established that plane wave soliton solutions are not stable for transverse perturbations

    Antibiotic Dosing in Critically Ill Patients Receiving CRRT : Underdosing is Overprevalent

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    Published CRRT drug dosing algorithms and other dosing guidelines appear to result in underdosed antibiotics, leading to failure to attain pharmacodynamic targets. High mortality rates persist with inadequate antibiotic therapy as the most important risk factor for death. Reasons for unintended antibiotic underdosing in patients receiving CRRT are many. Underdosing may result from lack of the recognition that better hepatic function in AKI patients yields higher nonrenal antibiotic clearance compared to ESRD patients. Other factors include the variability in body size and fluid composition of patients, the serious consequence of delayed achievement of antibiotic pharmacodynamic targets in septic patients, potential subtherapeutic antibiotic concentrations at the infection site, and the influence of RRT intensity on antibiotic concentrations. Too often, clinicians weigh the benefits of overcautious antibiotic dosing to avoid antibiotic toxicity too heavily against the benefits of rapid attainment of therapeutic antibiotic concentrations in critically ill patients receiving CRRT . We urge clinicians to prescribe antibiotics aggressively for these vulnerable patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108650/1/sdi12203.pd

    Design and control of a collision-resilient aerial vehicle with an icosahedron tensegrity structure

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    We present the tensegrity aerial vehicle, a design of collision-resilient rotor robots with icosahedron tensegrity structures. The tensegrity aerial vehicles can withstand high-speed impacts and resume operation after collisions. To guide the design process of these aerial vehicles, we propose a model-based methodology that predicts the stresses in the structure with a dynamics simulation and selects components that can withstand the predicted stresses. Meanwhile, an autonomous re-orientation controller is created to help the tensegrity aerial vehicles resume flight after collisions. The re-orientation controller can rotate the vehicles from arbitrary orientations on the ground to ones easy for takeoff. With collision resilience and re-orientation ability, the tensegrity aerial vehicles can operate in cluttered environments without complex collision-avoidance strategies. Moreover, by adopting an inertial navigation strategy of replacing flight with short hops to mitigate the growth of state estimation error, the tensegrity aerial vehicles can conduct short-range operations without external sensors. These capabilities are validated by a test of an experimental tensegrity aerial vehicle operating with only onboard inertial sensors in a previously-unknown forest.Comment: 12 pages, 16 figure

    Whittaker Mountain_Public_Relations_Intern

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    One of my main goals for this internship was to refine my communication skills for educating the public on environmental information. The main way I did this was through explaining Mt. Rainier’s new reservation system to people. This summer Mt. Rainier started requiring a reservation for entry into the park. Many people were not expecting this and therefore have not planned around it. What this has led to is people coming into the shop everyday and telling me they didn’t know about the system and saying they don’t know what to do next. My next step in this situation is to take the time to explain how to navigate the system and the reasons why it is in place. I have gotten better at doing this as time goes on because I now have a decent understanding of how people tend to react when they get this information. This has allowed me to shape my explanations in a format that people are most likely to listen to
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