529 research outputs found

    myTea: Connecting the Web to Digital Science on the Desktop

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    Bioinformaticians regularly access the hundreds of databases and tools that are available to them on the Web. None of these tools communicate with each other, causing the scientist to copy results manually from a Web site into a spreadsheet or word processor. myGrids' Taverna has made it possible to create templates (workflows) that automatically run searches using these databases and tools, cutting down what previously took days of work into hours, and enabling the automated capture of experimental details. What is still missing in the capture process, however, is the details of work done on that material once it moves from the Web to the desktop: if a scientist runs a process on some data, there is nothing to record why that action was taken; it is likewise not easy to publish a record of this process back to the community on the Web. In this paper, we present a novel interaction framework, built on Semantic Web technologies, and grounded in usability design practice, in particular the Making Tea method. Through this work, we introduce a new model of practice designed specifically to (1) support the scientists' interactions with data from the Web to the desktop, (2) provide automatic annotation of process to capture what has previously been lost and (3) associate provenance services automatically with that data in order to enable meaningful interrogation of the process and controlled sharing of the results

    Quantization of the Damped Harmonic Oscillator Revisited

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    We return to the description of the damped harmonic oscillator by means of a closed quantum theory with a general assessment of previous works, in particular the Bateman-Caldirola-Kanai model and a new model recently proposed by one of the authors. We show the local equivalence between the two models and argue that latter has better high energy behavior and is naturally connected to existing open-quantum-systems approaches.Comment: 16 page

    Melting of a colloidal crystal

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    A melting transition for a system of hard spheres interacting by a repulsive Yukawa potential of DLVO form is studied. To find the location of the phase boundary, we propose a simple theory to calculate the free energies for the coexisting liquid and solid. The free energy for the liquid phase is approximated by a virial expansion. The free energy of the crystalline phase is calculated in the spirit of the Lenard-Jonnes and Devonshire (LJD) theory. The phase boundary is found by equating the pressures and chemical potentials of the coexisting phases. When the approximation leading to the equation of state for the liquid breakes down, the first order transition line is also obtained by applying the Lindemann criterion to the solid phase. Our results are then compared with the Monte Carlo simulations.Comment: 7 pages, Revtex (using twocolumn style), four figures and postscript file. Submitted to Physica

    Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

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    We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC

    Single Spin Asymmetry ANA_N in Polarized Proton-Proton Elastic Scattering at s=200\sqrt{s}=200 GeV

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    We report a high precision measurement of the transverse single spin asymmetry ANA_N at the center of mass energy s=200\sqrt{s}=200 GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The ANA_N was measured in the four-momentum transfer squared tt range 0.003t0.0350.003 \leqslant |t| \leqslant 0.035 \GeVcSq, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of ANA_N and its tt-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this s\sqrt{s}, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure

    High pTp_{T} non-photonic electron production in pp+pp collisions at s\sqrt{s} = 200 GeV

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    We present the measurement of non-photonic electron production at high transverse momentum (pT>p_T > 2.5 GeV/cc) in pp + pp collisions at s\sqrt{s} = 200 GeV using data recorded during 2005 and 2008 by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The measured cross-sections from the two runs are consistent with each other despite a large difference in photonic background levels due to different detector configurations. We compare the measured non-photonic electron cross-sections with previously published RHIC data and pQCD calculations. Using the relative contributions of B and D mesons to non-photonic electrons, we determine the integrated cross sections of electrons (e++e2\frac{e^++e^-}{2}) at 3 GeV/c<pT< c < p_T <~10 GeV/cc from bottom and charm meson decays to be dσ(Be)+(BDe)dyeye=0{d\sigma_{(B\to e)+(B\to D \to e)} \over dy_e}|_{y_e=0} = 4.0±0.5\pm0.5({\rm stat.})±1.1\pm1.1({\rm syst.}) nb and dσDedyeye=0{d\sigma_{D\to e} \over dy_e}|_{y_e=0} = 6.2±0.7\pm0.7({\rm stat.})±1.5\pm1.5({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure

    Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

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    We present first measurements of the evolution of the differential transverse momentum correlation function, {\it C}, with collision centrality in Au+Au interactions at sNN=200\sqrt{s_{NN}} = 200 GeV. {\it C} exhibits a strong dependence on collision centrality that is qualitatively similar to that of number correlations previously reported. We use the observed longitudinal broadening of the near-side peak of {\it C} with increasing centrality to estimate the ratio of the shear viscosity to entropy density, η/s\eta/s, of the matter formed in central Au+Au interactions. We obtain an upper limit estimate of η/s\eta/s that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.

    Longitudinal scaling property of the charge balance function in Au + Au collisions at 200 GeV

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    We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage [-1.3, 1.3]. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes.Comment: 6 pages, 3 figure

    Measurement of the Bottom contribution to non-photonic electron production in p+pp+p collisions at s\sqrt{s} =200 GeV

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    The contribution of BB meson decays to non-photonic electrons, which are mainly produced by the semi-leptonic decays of heavy flavor mesons, in p+pp+p collisions at s=\sqrt{s} = 200 GeV has been measured using azimuthal correlations between non-photonic electrons and hadrons. The extracted BB decay contribution is approximately 50% at a transverse momentum of pT5p_{T} \geq 5 GeV/cc. These measurements constrain the nuclear modification factor for electrons from BB and DD meson decays. The result indicates that BB meson production in heavy ion collisions is also suppressed at high pTp_{T}.Comment: 6 pages, 4 figures, accepted by PR

    Resident Cellular Components of the Human Lung Current Knowledge and Goals for Research on Cell Phenotyping and Function

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    The purpose of the workshop was to identify still obscure or novel cellular components of the lung, to determine cell function in lung development and in health that impacts on disease, and to decide promising avenues for future research to extract and phenotype these cells. Since robust technologies are now available to identify, sort, purify, culture, and phenotype cells, progress is now within sight to unravel the origins and functional capabilities of lung cells in developmental stages and in disease. The Workshop's agenda was to first discuss the lung's embryologic development, including progenitor and stem cells, and then assess the functional and structural cells in three main compartments of the lung: (1) airway cells in bronchial and bronchiolar epithelium and bronchial glands (basal, secretory, ciliated, Clara, and neuroendocrine cells); (2) alveolar unit cells (Type 1 cells, Type 2 cells, and fibroblasts in the interstitium); and (3) pulmonary vascular cells (endothelial cells from different vascular structures, smooth muscle cells, and adventitial fibroblasts). The main recommendations were to: (1) characterize with better cell markers, both surface and nonsurface, the various cells within the lung, including progenitor cells and stem cells; (2) obtain more knowledge about gene expression in specific cell types in health and disease, which will provide insights into biological and pathologic processes; (3) develop more methodologies for cell culture, isolation, sorting, co-culture, and immortalization; and (4) promote tissue banks to facilitate the procurement of tissue from normal and from diseased lung for analysis at all levels
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