284,432 research outputs found

    Theta series and generalized special cycles on Hermitian locally symmetric manifolds

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    We study generalized special cycles on Hermitian locally symmetric spaces Γ\D\Gamma \backslash D associated to the groups G=U(p,q)G=\mathrm{U}(p,q), Sp(2n,R)\mathrm{Sp}(2n,\mathbb{R}) and O∗(2n)\mathrm{O}^*(2n). These cycles are (covered by) locally symmetric spaces associated to subgroups of GG which are of the same type. Using oscillator representation and a construction which essentially comes from the thesis of Greg Anderson, we show that Poincar\'e duals of these generalized special cycles can be viewed as Fourier coefficients of a theta series. This gives new cases of theta lifts from the cohomology of Hermtian locally symmetric manifolds associated to GG to vector valued automorphic forms associated to the groups G′=U(m,m)G'=\mathrm{U}(m,m), O(m,m)\mathrm{O}(m,m) or Sp(m,m)\mathrm{Sp}(m,m) which forms a reductive dual pair with GG in the sense of Howe

    Advanced Conducting Project

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    Contents include: Ave Verum Corpus, KV 618 by W.A. Mozart O Nata Lux by Thomas Tallis Requiem in D, K. 626, Hostias by W.A. Mozart Amavolovolo by Rudolf de Beer Son De Camaguey by Stephen Hatfield A La Nanita Nana by Greg Gilpin Can You Imagine by Rupert Lang A la Media Noche by Greg Gilpin Peace on this Silent Night by Cristi Cary Miller A Solfège Christmas by Cristi Cary Miller White is in the Winter Night by Audrey Snyder Frozen Choral Suite by Roger Emerson

    Evaluation of the Land Surface Water Budget in NCEP/NCAR and NCEP/DOE Reanalyses using an Off-line Hydrologic Model

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    The ability of the National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis (NRA1) and the follow-up NCEP/Department of Energy (DOE) reanalysis (NRA2), to reproduce the hydrologic budgets over the Mississippi River basin is evaluated using a macroscale hydrology model. This diagnosis is aided by a relatively unconstrained global climate simulation using the NCEP global spectral model, and a more highly constrained regional climate simulation using the NCEP regional spectral model, both employing the same land surface parameterization (LSP) as the reanalyses. The hydrology model is the variable infiltration capacity (VIC) model, which is forced by gridded observed precipitation and temperature. It reproduces observed streamflow, and by closure is constrained to balance other terms in the surface water and energy budgets. The VIC-simulated surface fluxes therefore provide a benchmark for evaluating the predictions from the reanalyses and the climate models. The comparisons, conducted for the 10-year period 1988–1997, show the well-known overestimation of summer precipitation in the southeastern Mississippi River basin, a consistent overestimation of evapotranspiration, and an underprediction of snow in NRA1. These biases are generally lower in NRA2, though a large overprediction of snow water equivalent exists. NRA1 is subject to errors in the surface water budget due to nudging of modeled soil moisture to an assumed climatology. The nudging and precipitation bias alone do not explain the consistent overprediction of evapotranspiration throughout the basin. Another source of error is the gravitational drainage term in the NCEP LSP, which produces the majority of the model\u27s reported runoff. This may contribute to an overprediction of persistence of surface water anomalies in much of the basin. Residual evapotranspiration inferred from an atmospheric balance of NRA1, which is more directly related to observed atmospheric variables, matches the VIC prediction much more closely than the coupled models. However, the persistence of the residual evapotranspiration is much less than is predicted by the hydrological model or the climate models

    Benefits for Deployable Quadrifilar Helical Antenna Modules for Small Satellites

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    Development of moored oceanographic spectroradiometer

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    Biospherical Instruments has successfully completed a NASA sponsored SBIR (Small Business Innovational Research Program) project to develop spectroradiometers capable of being deployed in the ocean for long periods of time. The completion of this project adds a valuable tool for the calibration of future spaceborne ocean color sensors and enables oceanographers to extend remote sensing optical techniques beyond the intermittent coverage of spaceborne sensors. Highlights of the project include two moorings totalling 8 months generating extensive sets of optical, biological, and physical data sets in the ocean off La Jolla, California, and a 70 day operational deployment of the resulting commercial product by the ONR and NASA sponsored BIOWATT program. Based on experience gained in these moorings, Biospherical Instruments has developed a new line of spectroradiometers designed to support the oceanographic remote sensing missions of NASA, the Navy, and various oceanographers

    The Evolution of X-Ray Clusters in a Cold Plus Hot Dark Matter Universe

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    We present the first self-consistently computed results on the evolution of X-ray properties of galaxy clusters in a Cold + Hot Dark Matter (CHDM) model. We have performed a hydrodynamic plus N-body simulation for the COBE-compatible CHDM model with standard mass components: Omega(hot) = 0.3, Omega(cold) = 0.6 and Omega(baryon) = 0.1 (h = 0.5). In contrast with the CDM model, which fails to reproduce the observed temperature distribution function dN/dT (Bryan et al. 1994b), the CHDM model fits the observational dN/dT quite well. Our results on X-ray luminosity are less firm but even more intriguing. We find that the resulting X-ray luminosity functions at redshifts z = 0.0, 0.2, 0.4, 0.7 are well fit by observations, where they overlap. The fact that both temperatures and luminosities provide a reasonable fit to the available observational data indicates that, unless we are missing some essential physics, there is neither room nor need for a large fraction of gas in rich clusters: 10% (or less) in baryons is sufficient to explain their X-ray properties. We also see a tight correlation between X-ray luminosity and gas temperature.Comment: 11 pages, 3 figures uuencoded postscript file, (92 kb), accepted for publication in Astrophysical Journal Letters. Also available via anonymous ftp at zeus.ncsa.uiuc.edu in gc3/publications/gc3005, LCA01

    Editorial Board

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    Editor-in Chief Nancy K. Moe Dye Managing Editor Richard A. Reep Technical Editor Gregory A. Luinstra Survey Editor Bruce O. Bekkedahl Staff Kenneth R. Dyrud Carol Everly Mary E. Harney Robert Isham Laura Lee Robert S. Marcott Greg S. Mullowney Joan Newman Richard Opp Robert C. Reichert W. Duncan Scott Faculty Advisor William L. Corbett Law Review Secretary Raneid M. Patric
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