1,995 research outputs found

    Paper Session II-C - Technology Transfer and The Office of Advanced Concepts and Technology

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    NASA has a continuing mission to develop and transfer advanced technologies for the benefit of government space programs, the aerospace industry and the nation\u27s economy. In October, 1992, the NASA Administrator created a new Office of Advanced Concepts and Technology (OACT) that is comprised of both the former NASA Office of Commercial Programs (OCP) and the Space Technology Directorate of the Office of Aeronautics and Space Technology (OAST). The purposes of this new office include the development of innovative new technologies and concepts, and the rapid and effective transfer of technology into and from NASA as well as other organizations participating in the U.S. civil space program. In this paper, the character and interrelationships of OACT programs and plans will be summarized, including overarching strategic planning (e.g. the Integrated Technology Plan, ITP); space technology development efforts (for example, the NASA base and focused space research and technology programs); special technology innovation efforts (such as the Small Business Innovative Research, SBIR, program); and, efforts to promote commercial space development (e.g. the Centers for Commercial Development of Space, CCDSs). Particular emphasis will be given to technology transfer programs and efforts to improve technology transfer (such as the on-going development of the national technology transfer network). This paper will describe both existing technology transfer programs and current planning, as well as assessment and analysis activities aimed at enabling OACT to refine and energize NASA\u27s approaches to technology transfer. It will also evaluate recent recommendations made by internal and external review teams and others concerning technology transfer for the civil space program. These include a 1992 workshop on Technology Transfer and the Civil Space Program, as well as the results of two internal NASA-wide teams. Finally, the paper will identify options for the future of civil space technology transfer improvements

    Transmission of an arenavirus in white-throated woodrats (Neotoma albigula), southeastern Colorado, 1995-1999.

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    From 1995 to 1999, we conducted longitudinal studies of white- throated woodrats (Neotoma albigula) in southeastern Colorado. Forty-five (42.9%) of 105 female and 15 (26.8%) of 56 male N. albigula had antibodies against Whitewater Arroyo virus (WWAV). Sixteen female and three male N. albigula seroconverted during the study period, most of them during July-November, when population densities are highest. Analyses of longevity data, minimum numbers alive and infected, movements, and weight data suggest that the dominant mode of WWAV transmission among white-throated woodrats in Colorado is direct contact. WWAV was recently reported to cause fatal infection in humans. Our findings will lead to better assessment of the public health threat posed by infected woodrats and may be useful in predicting periods of increased risk for human infection

    Multi-scale Renormalisation Group Improvement of the Effective Potential

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    Using the renormalisation group and a conjecture concerning the perturbation series for the effective potential, the leading logarithms in the effective potential are exactly summed for O(N)O(N) scalar and Yukawa theories.Comment: 19 pages, DIAS STP 94-09. Expanded to check large N limit, typo's corrected, to appear in Phys Rev

    Three-Dimensional Quantum Percolation Studied by Level Statistics

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    Three-dimensional quantum percolation problems are studied by analyzing energy level statistics of electrons on maximally connected percolating clusters. The quantum percolation threshold \pq, which is larger than the classical percolation threshold \pc, becomes smaller when magnetic fields are applied, i.e., \pq(B=0)>\pq(B\ne 0)>\pc. The critical exponents are found to be consistent with the recently obtained values of the Anderson model, supporting the conjecture that the quantum percolation is classified onto the same universality classes of the Anderson transition. Novel critical level statistics at the percolation threshold is also reported.Comment: to appear in the May issue of J. Phys. Soc. Jp

    Reliable change in neuropsychological assessment of breast cancer survivors

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    BACKGROUND: The purpose of this study was to enhance the current understanding and interpretation of longitudinal change on tests of neurocognitive function in individuals with cancer. Scores on standard neuropsychological instruments may be impacted by practice effects and other random forms of error. METHODS: The current study assessed the test-retest reliability of several tests and overarching cognitive domains comprising a neurocognitive battery typical of those used for research and clinical evaluation using relevant time frames. Practice effect-adjusted reliable change confidence intervals for test-retest difference scores based on a sample of patient-matched healthy controls are provided. RESULTS: By applying reliable change confidence intervals to scores from two samples of breast cancer patients at post-treatment follow-up assessment, meaningful levels of detectable change in cognitive functioning in breast cancer survivors were ascertained and indicate that standardized neuropsychological instruments may be subject to limitations in detection of subtle cognitive dysfunction over clinically relevant intervals, especially in patient samples with average to above average range baseline functioning. CONCLUSIONS: These results are discussed in relation to reported prevalence of cognitive change in breast cancer patients along with recommendations for study designs that enhance detection of treatment effects

    Dallas with balls: televized sport, soap opera and male and female pleasures

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    Two of the most popular of television genres, soap opera and sports coverage have been very much differentiated along gender lines in terms of their audiences. Soap opera has been regarded very much as a 'gynocentric' genre with a large female viewing audience while the audiences for television sport have been predominantly male. Gender differentiation between the genres has had implications for the popular image of each. Soap opera has been perceived as inferior; as mere fantasy and escapism for women while television sports has been perceived as a legitimate, even edifying experience for men. In this article the authors challenge the view that soap opera and television sport are radically different and argue that they are, in fact, very similar in a number of significant ways. They suggest that both genres invoke similar structures of feeling and sensibility in their respective audiences and that television sport is a 'male soap opera'. They consider the ways in which the viewing context of each genre is related to domestic life and leisure, the ways in which the textual structure and conventions of each genre invoke emotional identification, and finally, the ways in which both genres re-affirm gender identities

    Foot kinematics in patients with two patterns of pathological plantar hyperkeratosis

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    Background: The Root paradigm of foot function continues to underpin the majority of clinical foot biomechanics practice and foot orthotic therapy. There are great number of assumptions in this popular paradigm, most of which have not been thoroughly tested. One component supposes that patterns of plantar pressure and associated hyperkeratosis lesions should be associated with distinct rearfoot, mid foot, first metatarsal and hallux kinematic patterns. Our aim was to investigate the extent to which this was true. Methods: Twenty-seven subjects with planter pathological hyperkeratosis were recruited into one of two groups. Group 1 displayed pathological plantar hyperkeratosis only under metatarsal heads 2, 3 and 4 (n = 14). Group 2 displayed pathological plantar hyperkeratosis only under the 1st and 5th metatarsal heads (n = 13). Foot kinematics were measured using reflective markers on the leg, heel, midfoot, first metatarsal and hallux. Results: The kinematic data failed to identify distinct differences between these two groups of subjects, however there were several subtle (generally <3°) differences in kinematic data between these groups. Group 1 displayed a less everted heel, a less abducted heel and a more plantarflexed heel compared to group 2, which is contrary to the Root paradigm. Conclusions: There was some evidence of small differences between planter pathological hyperkeratosis groups. Nevertheless, there was too much similarity between the kinematic data displayed in each group to classify them as distinct foot types as the current clinical paradigm proposes

    The Kramers equation simulation algorithm II. An application to the Gross-Neveu model

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    We continue the investigation on the applications of the Kramers equation to the numerical simulation of field theoretic models. In a previous paper we have described the theory and proposed various algorithms. Here, we compare the simplest of them with the Hybrid Monte Carlo algorithm studying the two-dimensional lattice Gross-Neveu model. We used a Symanzik improved action with dynamical Wilson fermions. Both the algorithms allow for the determination of the critical mass. Their performances in the definite phase simulations are comparable with the Hybrid Monte Carlo. For the two methods, the numerical values of the measured quantities agree within the errors and are compatible with the theoretical predictions; moreover, the Kramers algorithm is safer from the point of view of the numerical precision.Comment: 20 pages + 1 PostScript figure not included, REVTeX 3.0, IFUP-TH-2

    Defect Formation and Critical Dynamics in the Early Universe

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    We study the nonequilibrium dynamics leading to the formation of topological defects in a symmetry-breaking phase transition of a quantum scalar field with \lambda\Phi^4 self-interaction in a spatially flat, radiation-dominated Friedmann-Robertson-Walker Universe. The quantum field is initially in a finite-temperature symmetry-restored state and the phase transition develops as the Universe expands and cools. We present a first-principles, microscopic approach in which the nonperturbative, nonequilibrium dynamics of the quantum field is derived from the two-loop, two-particle-irreducible closed-time-path effective action. We numerically solve the dynamical equations for the two-point function and we identify signatures of topological defects in the infrared portion of the momentum-space power spectrum. We find that the density of topological defects formed after the phase transition scales as a power law with the expansion rate of the Universe. We calculate the equilibrium critical exponents of the correlation length and relaxation time for this model and show that the power law exponent of the defect density, for both overdamped and underdamped evolution, is in good agreement with the "freeze-out" scenario of Zurek. We introduce an analytic dynamical model, valid near the critical point, that exhibits the same power law scaling of the defect density with the quench rate. By incorporating the realistic quench of the expanding Universe, our approach illuminates the dynamical mechanisms important for topological defect formation. The observed power law scaling of the defect density with the quench rate, observered here in a quantum field theory context, provides evidence for the "freeze-out" scenario in three spatial dimensions.Comment: 31 pages, RevTex, 8 figures in EPS forma
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