4,446 research outputs found
Space transportation systems, launch systems, and propulsion for the Space Exploration Initiative: Results from Project Outreach
A number of transportation and propulsion options for Mars exploration missions are analyzed. As part of Project Outreach, RAND received and evaluated 350 submissions in the launch vehicle, space transportation, and propulsion areas. After screening submissions, aggregating those that proposed identical or nearly identical concepts, and eliminating from further consideration those that violated known physical princples, we had reduced the total number of viable submissions to 213. In order to avoid comparing such disparate things as launch vehicles and electric propulsion systems, six broad technical areas were selected to categorize the submissions: space transportation systems; earth-to-orbit (ETO) launch systems; chemical propulsion; nuclear propulsion; low-thrust propulsion; and other. To provide an appropriate background for analyzing the submissions, an extensive survey was made of the various technologies relevant to the six broad areas listed above. We discuss these technologies with the intent of providing the reader with an indication of the current state of the art, as well as the advances that might be expected within the next 10 to 20 years
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Satisfaction guaranteed — “payment by results” for biologic agents
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Postdeployment military mental health training: Cross-national evaluations
Deployments increase risk for adjustment problems in service members. To mitigate this increased risk, mental health training programs have been developed and implemented in several nations. As part of a coordinated effort, three nations adapted a U.S. mental health training program that had been validated by a series of group randomized trials demonstrating improvement in postdeployment adjustment. Implementation of evidence-based programs in a new context is challenging: How much of the original program needs to remain intact in order to retain its utility? User satisfaction rates can provide essential data to assess how well a program is accepted. This article summarizes service member ratings of postdeployment mental health training and compares ratings from service members across four nations. The participating nations (Canada, New Zealand, United Kingdom, and the United States) administered mental health training to active duty military personnel in their respective nations. Following the training, military personnel completed an evaluation of the training. Overall, across the four nations, more than 70% of military personnel agreed or strongly agreed that they were satisfied with the mental health training. Although some differences in evaluations were observed across nations, components of training that were most important to overall satisfaction with the training were strikingly similar across nations. Fundamentally, it appears feasible that despite cultural and organizational differences, a mental health training program developed in one nation can be successfully adapted for use in other nations
Translation and Community in the work of Elizabeth Cary
Explores the role of female community within Elizabeth Cary\u27s translations and her play, The Tragedy of Mariam
Developing and applying heterogeneous phylogenetic models with XRate
Modeling sequence evolution on phylogenetic trees is a useful technique in
computational biology. Especially powerful are models which take account of the
heterogeneous nature of sequence evolution according to the "grammar" of the
encoded gene features. However, beyond a modest level of model complexity,
manual coding of models becomes prohibitively labor-intensive. We demonstrate,
via a set of case studies, the new built-in model-prototyping capabilities of
XRate (macros and Scheme extensions). These features allow rapid implementation
of phylogenetic models which would have previously been far more
labor-intensive. XRate's new capabilities for lineage-specific models,
ancestral sequence reconstruction, and improved annotation output are also
discussed. XRate's flexible model-specification capabilities and computational
efficiency make it well-suited to developing and prototyping phylogenetic
grammar models. XRate is available as part of the DART software package:
http://biowiki.org/DART .Comment: 34 pages, 3 figures, glossary of XRate model terminolog
Remarks on Causality in Relativistic Quantum Field Theory
It is shown that the correlations predicted by relativistic quantum field
theory in locally normal states between projections in local von Neumann
algebras \cA(V_1),\cA(V_2) associated with spacelike separated spacetime
regions have a (Reichenbachian) common cause located in the union of
the backward light cones of and . Further comments on causality and
independence in quantum field theory are made.Comment: 10 pages, Latex, Quantum Structures 2002 Conference Proceedings
submission. Minor revision of the order of definitions on p.
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