4,598 research outputs found

    Investigation of plasma accelerator /cyclotron resonance propulsion system/ Final report

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    Electron cyclotron resonance plasma accelerators for space propulsion system

    Successive Combination Jet Algorithm For Hadron Collisions

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    Jet finding algorithms, as they are used in e+ee^+ e^- and hadron collisions, are reviewed and compared. It is suggested that a successive combination style algorithm, similar to that used in e+ee^+ e^- physics, might be useful also in hadron collisions, where cone style algorithms have been used previously.Comment: 18 pages plus four uuencoded postscript figures, REVTEX 3.0, CERN-TH.6860/9

    The Ursinus Weekly, December 7, 1959

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    Podolak, Drummond crowned lady, lord • Folk Song Society presents concert Dec. 12 at U. of P. • Pi Nu Epsilon receives nine members in group • APO announces plans to decorate • WSGA legislates on enforcement of dress rules • Sue Pontius succeeds V. Miller as Ruby editor • Chapel service to be held by Chi Alpha Dec. 16 • Lehigh, Temple defeated by Ursinus debating team • 22nd annual Messiah to be given Thursday • Spanish Club celebrates Christmas with pinata • Mrs. Helfferich invites sophs, juniors to dessert • Library announces fines on overdue books • Attend math group meeting • Doris Bethke has poetry printed in anthology • Newman Club program features evolution topic • Editorial: Antidote to apathy • What\u27s wrong with marriage? • Steak from Salisbury • Socrates said • Oh, life! • Ursinus quintet drops close one to Pioneers • Intramural basketball to start after Christmas • Ursinus alumnae chosen for 1960 United States team at Washington • Basketball Grizzlies win over Philly drug • Preview of women\u27s winter sports activities • Greekvine • Sermon • Are you cultured? • To speak at Friends session • Thoughtshttps://digitalcommons.ursinus.edu/weekly/1351/thumbnail.jp

    Cancellation of Sudakov Logarithms in Radiative Decays of Quarkonia

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    We study infrared QCD effects in radiative quarkonia decays. We examine the endpoint region z -> 1 of the photon spectrum. We point out a cancellation mechanism for the corrections in αsnlnm(1z)\alpha_s^n \ln^{m} (1-z), m2nm \leq 2 n, in the short-distance coefficient for the color-singlet Fock state in the quarkonium. The cancellation is due to the coherence of the color radiation, and applies even though logarithmic contributions are present in the jet distributions associated with the decay. We comment on the implications of our results for the modeling of hadronization in the endpoint region and for the role of color-octet states in the quarkonium.Comment: 15 pages, 1 figur

    BˉXsγ\bar{B}\to X_s \gamma in the Two Higgs Doublet Model up to Next-to-Next-to-Leading Order in QCD

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    We compute three-loop matching corrections to the Wilson coefficients C7C_7 and C8C_8 in the Two Higgs Doublet Model by applying expansions for small, intermediate and large charged Higgs boson masses. The results are used to evaluate the branching ratio of BˉXsγ\bar{B}\to X_s \gamma to next-to-next-to leading order accuracy, and to determine an updated lower limit on the charged Higgs boson mass. We find \mhplus \ge 380 GeV at 95% confidence level when the recently completed BABAR data analysis is taken into account. Our results for the charged Higgs contribution to the branching ratio exhibit considerably weaker sensitivity to the matching scale μ0\mu_0, as compared to previous calculations.Comment: 20 pages, 15 figures; v2: minor modifications, matches published version in JHE

    Evaluation of NorESM-OC (versions 1 and 1.2), the ocean carbon-cycle stand-alone configuration of the Norwegian Earth System Model (NorESM1)

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    Idealised and hindcast simulations performed with the stand-alone ocean carbon-cycle configuration of the Norwegian Earth System Model (NorESM-OC) are described and evaluated. We present simulation results of two different model versions at different grid resolutions and using two different atmospheric forcing data sets. Model version NorESM-OC1 corresponds to the version that is included in the fully coupled model NorESM-ME1, which participated in CMIP5. The main update between NorESM-OC1 and NorESM-OC1.2 is the addition of two new options for the treatment of sinking particles. We find that using a constant sinking speed, which has been the standard in NorESM's ocean carbon cycle module HAMOCC (HAMburg Ocean Carbon Cycle model) does not transport enough particulate organic carbon (POC) into the deep ocean below approximately 2000 m depth. The two newly implemented parameterisations, a particle aggregation scheme with prognostic sinking speed, and a simpler scheme prescribing a linear increase of sinking speed with depth, provide better agreement with observed POC fluxes. Additionally, reduced deep ocean biases of oxygen and remineralised phosphate indicate a better performance of the new parameterisations. For model version 1.2, a re-tuning of the ecosystem parameterisation has been performed, which (i) reduces previously too high primary production in high latitudes, (ii) consequently improves model results for surface nutrients, and (iii) reduces alkalinity and dissolved inorganic carbon biases at low latitudes. We use hindcast simulations with prescribed observed and constant (pre-industrial) atmospheric CO2 concentrations to derive the past and contemporary ocean carbon sink. For the period 1990–1999 we find an average ocean carbon uptake ranging from 2.01 to 2.58 Pg C yr-1 depending on model version, grid resolution and atmospheric forcing data set

    Studies for a Photon Collider at the ILC

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    One option at the International Linear Collider is to convert the electron beams into high energy photon beams by Compton scattering a few millimetres in front of the interaction region. Selected physics channels for this option have been analysed and technical issues have been studied. So far no showstoppers for this option have been found.Comment: V2: Minor changes, accepted by NI

    Next-to-Leading Order Calculation of Four-Jet Shape Variables

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    We present the next-to-leading order calculation of two four-jet event shape variables, the D parameter and acoplanarity differential distributions. We find large, more than 100% radiative corrections. The theoretical prediction for the D parameter is compared to L3 data obtained at the Z peak and corrected to hadron level.Comment: 11 pages, latex with aps, epsf, rotate styles 3 tables, 3 figures typo in eq. 10 corrected, note and reference added, introduction revise

    Targeting atypical protein kinase C iota reduces viability in glioblastoma stem-like cells via a notch signaling mechanism

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    In a previous study, Protein Kinase C iota (PRKCI) emerged as an important candidate gene for glioblastoma (GBM) stem-like cell (GSC) survival. Here, we show that PKCι is overexpressed and activated in patient derived GSCs compared with normal neural stem cells and normal brain lysate, and that silencing of PRKCI in GSCs causes apoptosis, along with loss of clonogenicity and reduced proliferation. Notably, PRKCI silencing reduces tumor growth in vivo in a xenograft mouse model. PKCι has been intensively studied as a therapeutic target in non-small cell lung cancer, resulting in the identification of an inhibitor, aurothiomalate (ATM), which disrupts the PKCι/ERK signaling axis. However, we show that, although sensitive to pharmacological inhibition via a pseudosubstrate peptide inhibitor, GSCs are much less sensitive to ATM, suggesting that PKCι acts along a different signaling axis in GSCs. Gene expression profiling of PRKCI-silenced GSCs revealed a novel role of the Notch signaling pathway in PKCι mediated GSC survival. A proximity ligation assay showed that Notch1 and PKCι are in close proximity in GSCs. Targeting PKCι in the context of Notch signaling could be an effective way of attacking the GSC population in GBM

    Optimising assimilation of sea ice concentration in an Earth system model with a multicategory sea ice model

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    A data assimilation method capable of constraining the sea ice of an Earth system model in a dynamically consistent manner has the potential to enhance the accuracy of climate reconstructions and predictions. Finding such a method is challenging because the sea ice dynamics is highly non-linear, and sea ice variables are strongly non-Gaussian distributed and tightly coupled to the rest of the Earth system - particularly thermodynamically with the ocean. We investigate key practical implementations for assimilating sea ice concentration - the predominant source of observations in polar regions - with the Norwegian Climate Prediction Model that combines the Norwegian Earth System Model with the Ensemble Kalman Filter. The performances of the different configurations are investigated by conducting 10-year reanalyses in a perfect model framework. First, we find that with a flow-dependent assimilation method, strongly coupled ocean-sea ice assimilation outperforms weakly coupled (sea ice only) assimilation. An attempt to prescribe the covariance between the ocean temperature and the sea ice concentration performed poorly. Extending the ocean updates below the mixed layer is slightly beneficial for the Arctic hydrography. Second, we find that solving the analysis for the multicategory instead of the aggregated ice state variables greatly reduces the errors in the ice state. Updating the ice volumes induces a weak drift in the bias for the thick ice category that relates to the postprocessing of unphysical thicknesses. Preserving the ice thicknesses for each category during the assimilation mitigates the drift without degrading the performance. The robustness and reliability of the optimal setting is demonstrated for a 20-year reanalysis. The error of sea ice concentration reduces by 50% (65%), sea ice thickness by 25% (35%), sea surface temperature by 33% (23%) and sea surface salinity by 11% (25%) in the Arctic (Antarctic) compared to a reference run without assimilation
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