44 research outputs found

    The Phase Dynamics of Earthquakes: Implications for Forecasting in Southern California

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    We analyze the space-time patterns of earthquake occurrence in southern California using a new method that treats earthquakes as a phase dynamical system. The system state vector is used to obtain a probability measure for current and future earthquake occurrence. Thousands of statistical tests indicate the method has considerable forecast skill. We emphasize that the method is not a model, and there are no unconstrained or free parameters to be determined by fits to training data sets.Comment: email: [email protected]

    A Regional Climate Change Assessment Program for North America

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    There are two main uncertainties in determining future climate: the trajectories of future emissions of greenhouse gases and aerosols, and the response of the global climate system to any given set of future emissions [Meehl et al., 2007]. These uncertainties normally are elucidated via application of global climate models, which provide information at relatively coarse spatial resolutions. Greater interest in, and concern about, the details of climate change at regional scales has provided the motivation for the application of regional climate models, which introduces additional uncertainty [Christensen et al., 2007a]. These uncertainties in fine-scale regional climate responses, in contrast to uncertainties of coarser spatial resolution global models in which regional models are nested, now have been documented in numerous contexts [Christensen et al., 2007a] and have been found to extend to uncertainties in climate impacts [Wood et al., 2004; Oleson et al., 2007]. While European research in future climate projections has moved forward systematically to examine combined uncertainties from global and regional models [Christensen et al., 2007b], North American climate programs have lagged behind

    Surface Temperature Probability Distributions in the NARCCAP Hindcast Experiment: Evaluation Methodology, Metrics, and Results

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    Methodology is developed and applied to evaluate the characteristics of daily surface temperature distributions in a six-member regional climate model (RCM) hindcast experiment conducted as part of the North American Regional Climate Change Assessment Program (NARCCAP). A surface temperature dataset combining gridded station observations and reanalysis is employed as the primary reference. Temperature biases are documented across the distribution, focusing on the median and tails. Temperature variance is generally higher in the RCMs than reference, while skewness is reasonably simulated in winter over the entire domain and over the western United States and Canada in summer. Substantial differences in skewness exist over the southern and eastern portions of the domain in summer. Four examples with observed long-tailed probability distribution functions (PDFs) are selected for model comparison. Long cold tails in the winter are simulated with high fidelity for Seattle, Washington, and Chicago, Illinois. In summer, theRCMs are unable to capture the distribution width and long warm tails for the coastal location of Los Angeles, California, while long cold tails are poorly realized for Houston, Texas. The evaluation results are repeated using two additional reanalysis products adjusted by station observations and two standard reanalysis products to assess the impact of observational uncertainty. Results are robust when compared with those obtained using the adjusted reanalysis products as reference, while larger uncertainties are introduced when standard reanalysis is employed as reference. Model biases identified in this work will allow for further investigation into associated mechanisms and implications for future simulations of temperature extremes

    Precision measurements of the total and partial widths of the psi(2S) charmonium meson with a new complementary-scan technique in antiproton-proton annihilations

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    We present new precision measurements of the psi(2S) total and partial widths from excitation curves obtained in antiproton-proton annihilations by Fermilab experiment E835 at the Antiproton Accumulator in the year 2000. A new technique of complementary scans was developed to study narrow resonances with stochastically cooled antiproton beams. The technique relies on precise revolution-frequency and orbit-length measurements, while making the analysis of the excitation curve almost independent of machine lattice parameters. We study the psi(2S) meson through the processes pbar p -> e+ e- and pbar p -> J/psi + X -> e+ e- + X. We measure the width to be Gamma = 290 +- 25(sta) +- 4(sys) keV and the combination of partial widths Gamma_e+e- * Gamma_pbarp / Gamma = 579 +- 38(sta) +- 36(sys) meV, which represent the most precise measurements to date.Comment: 17 pages, 3 figures, 3 tables. Final manuscript accepted for publication in Phys. Lett. B. Parts of the text slightly expanded or rearranged; results are unchange

    Nonlinear Network Dynamics on Earthquake Fault Systems

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    Earthquake faults occur in networks that have dynamical modes not displayed by single isolated faults. Using simulations of the network of strike-slip faults in southern California, we find that the physics depends critically on both the interactions among the faults, which are determined by the geometry of the fault network, as well as on the stress dissipation properties of the nonlinear frictional physics, similar to the dynamics of integrate-and-fire neural networks.Comment: 12 pages, 4 figure

    An investigation of pressure ulcer risk, comfort and pain in medical imaging

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    In this study, we investigated the interface pressure of healthy volunteers on medical imaging (MI) table surfaces to determine the risks of developing pressure ulcers (PU). We also investigated volunteers’ perception of pain and comfort while lying on the MI table surfaces. Evidence from this study will enhance the understanding of factors contributing to PU formation and help improve service delivery to patients undergoing MI procedures

    A Study of \bar{p}p -> Two Neutral Pseudoscalar Mesons at the chi_c0(1^3P_0) Formation Energy

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    Fermilab experiment E835 has studied reactions \bar{p}p -> pi0 pi0, pi0 eta, eta eta, pi0 eta' and eta eta' in the energy region of the chi_c0(1^3P_0) from 3340 MeV to 3470 MeV. Interference between resonant and continuum production is observed in the pi0 pi0 and eta eta channels, and the product of the input and output branching fractions is measured. Limits on resonant production are set for the pi0 eta and pi0 eta' channels. An indication of interference is observed in the eta eta' channel. The technique for extracting resonance parameters in an environment dominated by continuum production is described.Comment: 15 pages, 21 figures, submitted Phys. Rev.

    Measurement of the Resonance Parameters of the χ1(13P1)\chi_{1}(1^3P_1) and χ2(13P2)\chi_{2}(1^3P_2) States of Charmonium formed in Antiproton-Proton Annihilations

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    We have studied the 3PJ^3P_J (χc)\chi_c) states of charmonium in formation by antiproton-proton annihilations in experiment E835 at the Fermilab Antiproton Source. We report new measurements of the mass, width, and B(χcJ→pˉp)×Γ(χcJ→J/ψ+anything)B(\chi_{cJ} \to \bar{p} p) \times \Gamma(\chi_{cJ} \to J/\psi + anything) for the χc1\chi_{c1} and χc2\chi_{c2} by means of the inclusive reaction pˉp→χcJ→J/ψ+anything→(e+e−)+anything\bar{p}p \to \chi_{cJ} \to J/\psi + anything \to (e^{+}e^{-}) +anything . Using the subsample of events where χcJ→γ+J/Ïˆâ†’Îł+(e+e−)\chi_{cJ} \to \gamma + J/\psi \to \gamma + (e^{+}e^{-}) is fully reconstructed, we derive B(χcJ→pˉp)×Γ(χcJ→J/ψ+Îł)B(\chi_{cJ} \to \bar p p)\times \Gamma(\chi_{cJ} \to J/\psi + \gamma) . We summarize the results of the E760 (updated) and E835 measurements of mass, width and B(χcJ→pˉp)Γ(χcJ→J/ψ+Îł) B(\chi_{cJ} \to \bar{p}p) \Gamma(\chi_{cJ} \to J/\psi+\gamma) (J=0,1,2) and discuss the significance of these measurements

    A View from the Past Into our Collective Future: The Oncofertility Consortium Vision Statement

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    Today, male and female adult and pediatric cancer patients, individuals transitioning between gender identities, and other individuals facing health extending but fertility limiting treatments can look forward to a fertile future. This is, in part, due to the work of members associated with the Oncofertility Consortium. The Oncofertility Consortium is an international, interdisciplinary initiative originally designed to explore the urgent unmet need associated with the reproductive future of cancer survivors. As the strategies for fertility management were invented, developed or applied, the individuals for who the program offered hope, similarly expanded. As a community of practice, Consortium participants share information in an open and rapid manner to addresses the complex health care and quality-of-life issues of cancer, transgender and other patients. To ensure that the organization remains contemporary to the needs of the community, the field designed a fully inclusive mechanism for strategic planning and here present the findings of this process. This interprofessional network of medical specialists, scientists, and scholars in the law, medical ethics, religious studies and other disciplines associated with human interventions, explore the relationships between health, disease, survivorship, treatment, gender and reproductive longevity. The goals are to continually integrate the best science in the service of the needs of patients and build a community of care that is ready for the challenges of the field in the future
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