2,682 research outputs found

    Speculations on Isolated Lepton Events at HERA

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    Speculations on mechanisms which might be responsible for events with an isolated high p_T lepton, a hadron jet and missing energy, as observed in the H1 experiment at HERA, are discussed.Comment: LaTeX, 6 pages, 2 figures, presented at the XXXI Conference of Theoretical Physics "Matter to the Deepest", Ustron, Poland, September 5-11, 200

    Long-Term Impacts of Military Drawdown on the Industrial Base

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    Since World War II, competition in the defense industry has fallen by over 90 percent. Over half of contracts currently executed by the United States Navy and Air Force are awarded without any competition. With the recent defense budget cuts, and an extended period of reduced defense spending ahead, more of which is going to sustainment and overhead than ever before, each year prime contractors are fighting over an even smaller piece of the procurement pie, which could have a deleterious effect on national security if these contractors go out of business or further consolidate through mergers. This study used data from the Federal Procurement Data System and the Securities Exchange Commission to track 13 of the DoD’s top 100 contractors from 2010 through 2015 to determine if a relationship exists between this reduced procurement spending and the financials indicators of the tracked companies. Three of the six models developed showed a relationship between procurement spending and financial indicators at the .05 significance level: those of Price-to-Earnings ratio, revenue, and revenue growth. The results of this study give cause for concern about the ever condensing defense industry and suggest that increased care be taken to ensure that the existing base of contractors be cultivated though strategic management of procurement funding

    Reconstructing Supersymmetry at ILC/LHC

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    Coherent analyses of experimental results from LHC and ILC will allow us to draw a comprehensive and precise picture of the supersymmetric particle sector. Based on this platform the fundamental supersymmetric theory can be reconstructed at the high scale which is potentially close to the Planck scale. This procedure will be reviewed for three characteristic examples: minimal supergravity as the paradigm; a left-right symmetric extension incorporating intermediate mass scales; and a specific realization of string effective theories.Comment: published in Proceedings of the Ustron Conference 2005; technical LaTeX problem correcte

    Hydraulic Lift and Soil Nutrient Heterogeneity

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    Water released at night from roots into upper portions of the soil profile in the process of hydraulic lift may contribute to reducing spatial soil nutrient heterogeneity. A manipulative field experiment was conducted in a semiarid shrub stand to determine if circumvention of hydraulic lift, by nighttime illumination of the shrub canopy, would result in greater soil nutrient heterogeneity than if the hydraulic lift process was allowed to operate. Nutrient-enriched patches were superimposed on the existing soil heterogeneity and after 40 days, the patches and interspaces were sampled for ions of different mobility and for root mass. There was no indication under these conditions that hydraulic lift was contributing to smoothing spatial nutrient heterogeneity

    Large‐scale hydro‐climatology of the terrestrial Arctic drainage system

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    The large‐scale hydro‐climatology of the terrestrial Arctic drainage system is examined, focusing on the period 1960 onward. Special attention is paid to the Ob, Yenisey, Lena, and Mackenzie watersheds, which provide the bulk of freshwater discharge to the Arctic Ocean. Station data are used to compile monthly gridded time series of gauge‐corrected precipitation (P). Gridded time series of precipitation minus evapotranspiration (P−ET) are calculated from the moisture flux convergence using NCEP reanalysis data. Estimates of ET are obtained as a residual. Runoff (R) is obtained from available discharge records. For long‐term water‐year means, P−ET for the Yenisey, Lena, and Mackenzie watersheds is 16–20% lower than the observed runoff. In the Ob watershed, the two values agree within 9%. Given the uncertainties in P−ET, we consider the atmospheric and surface water budgets to be reasonably closed. Compared to the other three basins, the mean runoff ratio (R/P) is lower in the Ob watershed, consistent with the high fraction of annual precipitation lost through ET. All basins exhibit summer maxima in P and minima in P−ET. Summer P−ET in the Ob watershed is negative due to high ET rates. For large domains in northern Eurasia, about 25% of July precipitation is associated with the recycling of water vapor evapotranspirated within each domain. This points to a significant effect of the land surface on the hydrologic regime. Variability in P and P−ET has generally clear associations with the regional atmospheric circulation. A strong link with the Urals trough is documented for the Ob. Relationships with indices of the Arctic Oscillation and other teleconnections are generally weak. Water‐year time series of runoff and P−ET are strongly correlated in the Lena watershed only, reflecting extensive permafrost. Cold‐season runoff has increased in the Yenisey and Lena watersheds. This is most pronounced in the Yenisey watershed, where runoff has also increased sharply in spring, decreased in summer, but has increased for the year as a whole. The mechanisms for these changes are not entirely clear. While they fundamentally relate to higher air temperatures, increased winter precipitation, and strong summer drying, we speculate links with changes in active layer thickness and thawing permafrost
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