798 research outputs found

    PAN AIR: A computer program for predicting subsonic or supersonic linear potential flows about arbitrary configurations using a higher order panel method. Volume 3: Case manual (version 1.0)

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    Numerous applications of the PAN AIR computer program system are presented. PAN AIR is user-oriented tool for analyzing and/or designing aerodynamic configurations in subsonic or supersonic flow using a technique generally referred to as a higher order panel method. Problems solved include simple wings in subsonic and supersonic flow, a wing-body in supersonic flow, wing with deflected flap in subsonic flow, design of two-dimensional and three-dimensional wings, axisymmetric nacelle in supersonic flow, and wing-canard-tail-nacelle-fuselage combination in supersonic flow

    PAN AIR: A computer program for predicting subsonic or supersonic linear potential flows about arbitrary configurations using a higher order panel method. Volume 2: User's manual (version 3.0)

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    A comprehensive description of user problem definition for the PAN AIR (Panel Aerodynamics) system is given. PAN AIR solves the 3-D linear integral equations of subsonic and supersonic flow. Influence coefficient methods are used which employ source and doublet panels as boundary surfaces. Both analysis and design boundary conditions can be used. This User's Manual describes the information needed to use the PAN AIR system. The structure and organization of PAN AIR are described, including the job control and module execution control languages for execution of the program system. The engineering input data are described, including the mathematical and physical modeling requirements. Version 3.0 strictly applies only to PAN AIR version 3.0. The major revisions include: (1) inputs and guidelines for the new FDP module (which calculates streamlines and offbody points); (2) nine new class 1 and class 2 boundary conditions to cover commonly used modeling practices, in particular the vorticity matching Kutta condition; (3) use of the CRAY solid state Storage Device (SSD); and (4) incorporation of errata and typo's together with additional explanation and guidelines

    Inhibition of measles virus replication by 5\u27-Norcarbocyclic nucleoside analogs

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    Despite intense efforts to increase vaccine coverage, measles virus (MV) still causes significant morbidity and mortality in the world, sometimes as the result of severe, chronic, lethal disease. In an effort to develop therapies to supplement immunization strategies, a number of 5′-nor carbocyclic adenosine analogues were evaluated for anti-MV activity in CV-1 monkey kidney cells. Of those compounds tested, those either unsubstituted at C4 or possessing a hydroxyl, azido or amino substituent at that position were the most active, with particularly significant inhibition of MV, strain Chicago-1. The EC50 values against this strain ranged from100 mg/ml in actively growing and stationary-phase cells. Results suggest that these compounds may be clinically useful anti-MV virus agents

    A first measurement of the interaction cross section of the tau neutrino

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    The DONuT experiment collected data in 1997 and published first results in 2000 based on four observed ντ\nu_\tau charged-current (CC) interactions. The final analysis of the data collected in the experiment is presented in this paper, based on 3.6×10173.6 \times 10^{17} protons on target using the 800 GeV Tevatron beam at Fermilab. The number of observed ντ\nu_\tau CC interactions is 9, from a total of 578 observed neutrino interactions. We calculated the energy-independent part of the tau-neutrino CC cross section (ν+νˉ\nu + \bar \nu), relative to the well-known νe\nu_e and νμ\nu_\mu cross sections. The ratio σ(ντ)\sigma(\nu_\tau)/σ(νe,μ)\sigma(\nu_{e,\mu}) was found to be 1.37±0.35±0.771.37\pm0.35\pm0.77. The ντ\nu_\tau CC cross section was found to be 0.72±0.24±0.36×10380.72 \pm 0.24\pm0.36 \times 10^{-38} cm2GeV1^{2}\rm{GeV}^{-1}. Both results are in agreement the Standard Model.Comment: 37 pages, 15 figure

    Coumarins and pyranocoumarins, potential novel pharmacophores for inhibition ofmeasles virus replication

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    A series of coumarin and pyranocoumarin analogues were evaluated in vitro for antiviral efficacy against measles virus (MV), strain Chicago. Of the 22 compounds tested for inhibition, six were found to have selectivity indices greater than 10. These were compounds 5-hydroxy-7-propionyloxy- 4-propylcoumarin (2a), 5,7-bis(tosyloxy)-4- propylcoumarin (7); 5-hydroxy-4-propyl-7-tosyloxy- coumarin (8); 6,6-dimethyl-9-propionyloxy-4- propyl-2H,6H-benzo[1,2-b:3,4-b′]dipyran-2-one (9); 6,6-dimethyl-9-pivaloyloxy-4-propyl-2H,6Hbenzo[ 1,2-b:3,4-b′]dipyran-2-one (10); and 7,8-cis- 10,11,12-trans-4-propyl-6,6,10,11-tetramethyl- 7,8,9-trihydroxy-2H,6H,12H-benzo[1,2-b:3,4-b′:5,6- b′′]tripyran-2-one (18). Three of the active drugs were propyl coumarin analogues (2a, 7 and 8), two were dipyranone or chromeno-coumarins (9 and 10), and one was a benzotripyranone with a coumarin nucleus (18). Some appeared to be rather specific and potent inhibitors of MV with EC50 values ranging from 0.2 to 50 μg/ml and the majority of the EC50 values being less than 5 μg/ml. The compounds inhibited an additional nine strains of MV, and in virucidal tests the drugs did not physically disrupt the virion to inhibit virus replication. The inhibitory activity for one of the compounds tested (7) was somewhat dependent on virus concentration and it was still active when added to cells up to 24 h after virus exposure. When used in combination with ribavirin, compound 7 appeared not to profoundly affect the antiviral efficacy of ribavirin or its cell-associated toxicity. However, a slightly antagonistic MVinhibitory effect was observed at the highest concentration of ribavirin used in combination with most concentrations of compound 7 tested. This and related compounds may be valuable leads in the development of a potent and selective class of MV inhibitors that could be used in future in the clinic

    The TeV spectrum of H1426+428

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    The BL Lac object H1426+428 was recently detected as a high energy gamma-ray source by the VERITAS collaboration (Horan et al. 2002). We have reanalyzed the 2001 portion of the data used in the detection in order to examine the spectrum of H1426+428 above 250 GeV. We find that the time-averaged spectrum agrees with a power law of the shape dF/dE = 10^(-7.31 +- 0.15(stat) +- 0.16(syst)) x E^(-3.50 +- 0.35(stat) +- 0.05(syst)) m^(-2)s^(-1)TeV^(-1) The statistical evidence from our data for emission above 2.5 TeV is 2.6 sigma. With 95% c.l., the integral flux of H1426+428 above 2.5 TeV is larger than 3% of the corresponding flux from the Crab Nebula. The spectrum is consistent with the (non-contemporaneous) measurement by Aharonian et al. (2002) both in shape and in normalization. Below 800 GeV, the data clearly favours a spectrum steeper than that of any other TeV Blazar observed so far indicating a difference in the processes involved either at the source or in the intervening space.Comment: LaTeX, 8 pages, 4 figures, accepted for publication in Ap

    Detection of the BL Lac Object H1426+428 at TeV Gamma Ray Energies

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    A very high energy (VHE) gamma-ray signal has been detected at the 5.4 sigma level from H1426+428, an x-ray selected BL Lacertae object at a redshift of 0.129. The object was monitored from 1995 - 1998 with the Whipple 10m imaging atmospheric Cherenkov telescope as part of a general blazar survey; the results of these observations, although not statistically significant, were consistently positive. X-ray observations of H1426+428 during 1999 with the BeppoSAX instrument revealed that the peak of its synchrotron spectrum occurs at > 100 keV, leading to the prediction of observable TeV emission from this object. H1426+428 was monitored extensively at the Whipple Observatory during the 1999, 2000, and 2001 observing seasons. The strongest TeV signals were detected in 2000 and 2001. During 2001, an integral flux of 2.04 +/- 0.35 x10e-11 cm-2 s-1 above 280 GeV was recorded from H1426+428. The detection of H1426+428 supports the idea that, as also seen in Markarian 501 and 1ES2344+514, BL Lacertae objects with extremely high synchrotron peak frequencies produce gamma rays in the TeV range.Comment: 35 pages, 7 figures, accepted by ApJ Two upper limits in Table 3 (upper limits for 1995 and 1997) are different from the ApJ versio

    Fermilab E791

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    Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab's Tagged Photon Laboratory. Over 20 billion events were recorded through a loose transverse energy trigger and written to 8mm tape in the the 1991-92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysed on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays.Comment: 4 pages, 1 figure, LaTe

    Measurement of the Ds Lifetime

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    We report the results of a precise measurement of the Ds meson lifetime based on 1662 +/- 56 fully reconstructed Ds -> phi pi decays, from the charm hadroproduction experiment E791 at Fermilab. Using an unbinned maximum likelihood fit, we measure the Ds lifetime to be 0.518 +/- 0.014 +/- 0.007 ps. The ratio of the measured Ds lifetime to the world average D0 lifetime is 1.25 +/- 0.04. This result differs from unity by six standard deviations, indicating significantly different lifetimes for the Ds and the D0.Comment: 12 pages, 3 figures, 2 table. LaTe
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