699 research outputs found

    The NASA/OAST telerobot testbed architecture

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    Through a phased development such as a laboratory-based research testbed, the NASA/OAST Telerobot Testbed provides an environment for system test and demonstration of the technology which will usefully complement, significantly enhance, or even replace manned space activities. By integrating advanced sensing, robotic manipulation and intelligent control under human-interactive supervision, the Testbed will ultimately demonstrate execution of a variety of generic tasks suggestive of space assembly, maintenance, repair, and telescience. The Testbed system features a hierarchical layered control structure compatible with the incorporation of evolving technologies as they become available. The Testbed system is physically implemented in a computing architecture which allows for ease of integration of these technologies while preserving the flexibility for test of a variety of man-machine modes. The development currently in progress on the functional and implementation architectures of the NASA/OAST Testbed and capabilities planned for the coming years are presented

    New high order relations between physical observables in perturbative QCD

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    We exploit the fact that within massless perturbative QCD the same Green's function determines the hadronic contribution to the τ\tau decay width and the moments of the e+e−e^+e^- cross section. This allows one to obtain relations between physical observables in the two processes up to an unprecedented high order of perturbative QCD. A precision measurement of the τ\tau decay width allows one then to predict the first few moments of the spectral density in e+e−e^+e^- annihilations integrated up to s∌mτ2s\sim m_\tau^2 with high accuracy. The proposed tests are in reach of present experimental capabilities.Comment: 7 pages, Latex, no figure

    The Radiative Decay of Vector Mesons

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    In this paper, radiative decays ρ0→π+Ï€âˆ’Îł,π0π0Îł\rho^0 \to \pi^+\pi^-\gamma, \pi^0\pi^0\gamma ,ϕ→K+K−γ,K0K0ˉγ\phi \to K^+K^-\gamma, K^0 \bar{K^0}\gamma are studied systematically in the U(3)_L\timesU(3)_R chiral theory of mesons. The theoretical differential spectrum with respect to photon energy and branch ratio for ρ0→π+Ï€âˆ’Îł\rho^0 \to \pi^+\pi^-\gamma agree well with the experimental data. Differential spectrums and branch ratios for ρ0→π0π0Îł,ϕ→K+K−γ,ϕ→K0K0ˉγ\rho^0 \to \pi^0\pi^0\gamma, \phi \to K^+ K^-\gamma,\phi \to K^0\bar{K^0}\gamma are predicted. The process ϕ→K0K0ˉγ\phi \to K^0 \bar{K^0} \gamma is relevant to precision measurment of CP-violation parameters in the kaon systerm at a ϕ\phi-factory. We give a complete estimate of the branch ratio for this decay process by including scalar resonance f0,a0f_0, a_0 poles, nonresonant smooth amplitude and an abnormal parity process with K∗K^* pole which hasn't been considered before. We conclude that processes with intermediate K∗K^* do not pose a potential background problem for ϕ→K0Kˉ0\phi\to K^0\bar{K}^0 CP violation experiments.Comment: Revtex file, 12 pages, 9 eps figure

    Hereditary predisposition to ovarian cancer, looking beyond BRCA1/BRCA2

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    AbstractObjectiveGenetic predisposition to ovarian cancer is well documented. With the advent of next generation sequencing, hereditary panel testing provides an efficient method for evaluating multiple genes simultaneously. Therefore, we sought to investigate the contribution of 19 genes identified in the literature as increasing the risk of hereditary breast and ovarian cancer (HBOC) in a BRCA1 and BRCA2 negative population of patients with a personal history of breast and/or ovarian cancer by means of a hereditary cancer panel.MethodsSubjects were referred for multi-gene panel testing between February 2012 and March 2014. Clinical data was ascertained from requisition forms. The incidence of pathogenic mutations (including likely pathogenic), and variant of unknown significance were then calculated for each gene and/or patient cohort.ResultsIn this cohort of 911 subjects, panel testing identified 67 mutations. With 7.4% of subjects harboring a mutation on this multi-gene panel, the diagnostic yield was increased, compared to testing for BRCA1 and BRCA2 mutations alone. In the ovarian cancer probands, the most frequently mutated genes were BRIP1 (n=8; 1.72%) and MSH6 (n=6; 1.29%). In the breast cancer probands, mutations were most commonly observed in CHEK2 (n=9; 2.54%), ATM (n=3; 0.85%), and TP53 (n=3; 0.85%).ConclusionsAlthough further studies are needed to clarify the exact management of patients with a mutation in each gene, this study highlights information that can be captured with panel testing and provides support for incorporation of panel testing into clinical practice

    Running mass of the rho0 meson's implication for the dilepton mass spectrum and the mu+mu-/e+e- branching ratio in the K+ --> pi+l+l- decays

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    We make an attempt to resolve the discrepancy of the observed e+e- mass spectrum in the K+ --> pi+e+e- decay with that predicted by meson dominance. To this end we investigate the properties of the rho0 propagator. We use dispersion relations to evaluate the running mass squared m_rho^2(t) of the rho0 resonance without adjustable parameters. To improve the convergence of the dispersion integral, the momentum dependence of strong vertices is taken from the flux-tube-breaking model of Kokoski and Isgur. The obtained behavior of m_rho^2(t) at small momentum squared t makes the K+ --> pi+e+e- form factor rise faster with increasing tt than in the original meson-dominance calculation and more in agreement with the published data. As a consequence, the meson-dominance prediction of the mu+mu-/e+e- branching ratio changes slightly, from 0.224 to 0.236. We do not see any possibility to accommodate into the meson-dominance approach an even steeper e+e- spectrum, indicated by the preliminary data of the E865 collaboration at BNL AGS.Comment: 13 pages, RevTeX, epsf.sty, 4 embedded figure

    Formalism for dilepton production via virtual photon bremsstrahlung in hadronic reactions

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    We derive a set of new formulas for various distributions in dilepton production via virtual photon bremsstrahlung from pseudoscalar mesons and unpolarized spin-one-half fermions. These formulas correspond to the leading and sub-leading terms in the Low-Burnett-Kroll expansion for real photon bremsstrahlung. The relation of our leading-term formulas to previous works is also shown. Existing formulas are examined in the light of Lorentz covariance and gauge invariance. Numerical comparison is made in a simple example, where an "exact" formula and real photon data exist. The results reveal large discrepancies among different bremsstrahlung formulas. Of all the leading-term bremsstrahlung formulas, the one derived in this work agrees best with the exact formula. The issues of M_T-scaling and event generators are also addressed.Comment: 37 pages, RevTeX, epsf.sty, 10 embedded figure

    Study of ÎłÏ€â†’Ï€Ï€\gamma\pi \to \pi\pi below 1 GeV using Integral Equation Approach

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    The scattering of ÎłÏ€â†’Ï€Ï€\gamma \pi \to \pi \pi is studied using the axial anomaly, elastic unitarity, analyticity and crossing symmetry. Using the technique to derive the Roy's equation, an integral equation for the P-wave amplitude is obtained in terms of the strong P-wave pion pion phase shifts. Its solution is obtained numerically by an iteration procedure using the starting point as the solution of the integral equation of the Muskelshsvilli-Omnes type. It is, however, ambiguous and depends sensitively on the second derivative of the P-wave amplitude at s=mπ2s=m_\pi^2 which cannot directly be measured.Comment: 26 pages, 10 figure

    Opal web services for biomedical applications

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    Biomedical applications have become increasingly complex, and they often require large-scale high-performance computing resources with a large number of processors and memory. The complexity of application deployment and the advances in cluster, grid and cloud computing require new modes of support for biomedical research. Scientific Software as a Service (sSaaS) enables scalable and transparent access to biomedical applications through simple standards-based Web interfaces. Towards this end, we built a production web server (http://ws.nbcr.net) in August 2007 to support the bioinformatics application called MEME. The server has grown since to include docking analysis with AutoDock and AutoDock Vina, electrostatic calculations using PDB2PQR and APBS, and off-target analysis using SMAP. All the applications on the servers are powered by Opal, a toolkit that allows users to wrap scientific applications easily as web services without any modification to the scientific codes, by writing simple XML configuration files. Opal allows both web forms-based access and programmatic access of all our applications. The Opal toolkit currently supports SOAP-based Web service access to a number of popular applications from the National Biomedical Computation Resource (NBCR) and affiliated collaborative and service projects. In addition, Opal’s programmatic access capability allows our applications to be accessed through many workflow tools, including Vision, Kepler, Nimrod/K and VisTrails. From mid-August 2007 to the end of 2009, we have successfully executed 239 814 jobs. The number of successfully executed jobs more than doubled from 205 to 411 per day between 2008 and 2009. The Opal-enabled service model is useful for a wide range of applications. It provides for interoperation with other applications with Web Service interfaces, and allows application developers to focus on the scientific tool and workflow development. Web server availability: http://ws.nbcr.net

    Rho primes in analyzing e+e- annihilation, MARK III, LASS and ARGUS data

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    The results of an analysis are presented of some recent data on the reactions e+e−→π+π−π+π−e^+e^-\to\pi^+\pi^-\pi^+\pi^-, e+e−→π+π−π0π0e^+e^-\to\pi^+\pi^-\pi^0\pi^0 with the subtracted ωπ0\omega\pi^0 events, e+e−→ωπ0e^+e^-\to\omega\pi^0, e+e−→ηπ+π−e^+e^-\to\eta \pi^+\pi^-, e+e−→π+π−e^+e^-\to\pi^+\pi^-, K−p→π+π−ΛK^-p\to\pi^+\pi^-\Lambda, the decays J/ψ→π+π−π0J/\psi\to\pi^+\pi^-\pi^0, tau−→Μtauπ+π−π−π0tau^-\to\nu_tau\pi^+\pi^-\pi^-\pi^0 tau−→Μτωπ−tau^-\to\nu_\tau\omega\pi^-, upon taking into account both the strong energy dependence of the partial widths on energy and the previously neglected mixing of the ρ\rho type resonances. The above effects are shown to exert an essential influence on the specific values of masses and coupling constants of heavy resonances and hence are necessary to be accounted for in establishing their true nature.Comment: 20 pages, ReVTeX, 9 Postscript figures As compared to hep-ph/9607398, new material concerning the analysis of the ARGUS data on the tau decays into four pion hadronic states is adde

    VMD description of τ→(ω, ϕ)π−Μτ\tau \to (\omega,\ \phi) \pi^- \nu_{\tau} decays and the ω−ϕ\omega-\phi mixing angle

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    Using the vector meson dominance model we get predictions for the Cabibbo-favored \tom and \tphi decays. We show how the measurements of these two decays can provide information on the nature of the violation of the OZI rule.Comment: A misprint in Eqs. (14) has been correcte
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