3,048 research outputs found

    Saturn integrated circuit reliability test program Final report, 28 Jun. 1966 - 1 Jul. 1967

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    Literature survey and test program to study reliability of linear integrated circuit

    Handling uncertainties in background shapes: the discrete profiling method

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    A common problem in data analysis is that the functional form, as well as the parameter values, of the underlying model which should describe a dataset is not known a priori. In these cases some extra uncertainty must be assigned to the extracted parameters of interest due to lack of exact knowledge of the functional form of the model. A method for assigning an appropriate error is presented. The method is based on considering the choice of functional form as a discrete nuisance parameter which is profiled in an analogous way to continuous nuisance parameters. The bias and coverage of this method are shown to be good when applied to a realistic example.Comment: Accepted by J.Ins

    Nimbus power systems /1960 - 1969/

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    Power supply subsystems for use on Nimbus satellite progra

    Does neighborhood disorder predict recovery from mobility limitation? Findings from the Health and Retirement Study

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    Objective: This research explores whether perceptions of physical neighborhood disorder predict recovery from mobility limitation over a 2-year period and examines whether psychosocial factors (i.e., depressive symptomology and mastery) and physical activity are salient mediators. Method: Using data from the Health and Retirement Study (HRS): Participant Lifestyle Questionnaire (2008-2010), odds ratio estimates of recovery were ascertained using binary logistic regression, and post hoc Sobel tests were conducted to formally assess mediation. Results: Net of demographic characteristics and socioeconomic status, increased neighborhood disorder was associated with lower odds of recovery. However, both psychosocial indicators and physical activity were significant individual partial mediators, which suggest neighborhood disorder influences recovery from physical impairment via psychosocial processes and barriers to physical activity. Discussion: Reducing neighborhood disorder may enhance older residents’ psychosocial well-being and improve participation in physical activity, thus increasing recovery from mobility limitation and preventing subsequent disability

    A study to develop neutron activation for measuring bone calcium content

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    Neutron activation analysis for measuring calcium in monkey bone

    The Upper Limit Solar Gamma-ray Spectrum to 10 Mev

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    Balloon flight data on upper limit solar gamma ray spectrum from quiet su

    Saturn integrated circuit reliability test program Quarterly progress report, Jul. - Sep. 1966

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    Saturn integrated circuit reliability tests performed to improve failure mode screenin

    System Dynamics Modeling for Cancer Prevention and Control: A systematic review

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    Cancer prevention and control requires consideration of complex interactions between multilevel factors. System dynamics modeling, which consists of diagramming and simulation approaches for understanding and managing such complexity, is being increasingly applied to cancer prevention and control, but the breadth, characteristics, and quality of these studies is not known. We searched PubMed, Scopus, APA PsycInfo, and eight peer-reviewed journals to identify cancer-related studies that used system dynamics modeling. A dual review process was used to determine eligibility. Included studies were assessed using quality criteria adapted from prior literature and mapped onto the cancer control continuum. Characteristics of studies and models were abstracted and qualitatively synthesized. 32 studies met our inclusion criteria. A mix of simulation and diagramming approaches were used to address diverse topics, including chemotherapy treatments (16%), interventions to reduce tobacco or e-cigarettes use (16%), and cancer risk from environmental contamination (13%). Models spanned all focus areas of the cancer control continuum, with treatment (44%), prevention (34%), and detection (31%) being the most common. The quality assessment of studies was low, particularly for simulation approaches. Diagramming-only studies more often used participatory approaches. Involvement of participants, description of model development processes, and proper calibration and validation of models showed the greatest room for improvement. System dynamics modeling can illustrate complex interactions and help identify potential interventions across the cancer control continuum. Prior efforts have been hampered by a lack of rigor and transparency regarding model development and testing. Supportive infrastructure for increasing awareness, accessibility, and further development of best practices of system dynamics for multidisciplinary cancer research is needed

    Turbulence and particle acceleration in collisionless supernovae remnant shocks: II- Cosmic-ray transport

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    Supernovae remnant shock waves could be at the origin of cosmic rays up to energies in excess of the knee (E31015E\simeq3\cdot 10^{15} eV) if the magnetic field is efficiently amplified by the streaming of accelerated particles in the shock precursor. This paper follows up on a previous paper \citep{pell05} which derived the properties of the MHD turbulence so generated, in particular its anisotropic character, its amplitude and its spectrum. In the present paper, we calculate the diffusion coefficients, also accounting for compression through the shock, and show that the predicted three-dimensional turbulence spectrum kS3d(k,k)k1kαk_\perp S_{3\rm d}(k_\parallel,k_\perp)\propto k_\parallel^{-1}k_\perp^{-\alpha} (with kk_\parallel and kk_\perp the wavenumber components along and perpendicular to the shock normal) generally leads to Bohm diffusion in the parallel direction. However, if the anisotropy is constrained by a relation of the form kk2/3k_\parallel \propto k_\perp^{2/3}, which arises when the turbulent energy cascade occurs at a constant rate independent of scale, then the diffusion coefficient loses its Bohm scaling and scales as in isotropic Kolmogorov turbulence. We show that these diffusion coefficients allow to account for X-ray observations of supernova remnants. This paper also calculates the modification of the Fermi cycle due to the energy lost by cosmic rays in generating upstream turbulence and the concomittant steepening of the energy spectrum. Finally we confirm that cosmic rays can produced an amplified turbulence in young SNr during their free expansion phase such that the maximal energy is close to the knee and the spectral index is close to 2.3 in the warm phase of the interstellar mediumComment: 13 pages, 4 figures, accepted for publication in Astronomy & Astrophysics main journa
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