972 research outputs found
First Observation of Diboson Production in Hadronic Final State at the Tevatron
We present the first observation in hadronic collisions of the electroweak
production of vector boson pairs (VV; V = W,Z) where one boson decays to a
hadronic final state. The data correspond to 3.5/fb of integrated luminosity
collected by the CDF II detector in p-pbar collisions at a center-of-mass
energy of 1.96 TeV. Event selection requires two identified jets and large
transverse momentum imbalance. The analysis employs several novel techniques to
suppress multijet background and reduce systematic uncertainties. We observe
1516 +/- 239(stat) +/- 144(syst) diboson candidate events and measure a cross
section of sigma(ppbar to VV+X) = 18.0 +/- 2.8(stat) +/- 2.4(syst) +/-
1.1(lumi) pb, in agreement with standard model expectations.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July
2009, eConf C090726 (6 pages, 4 figures, 2 tables
Efficient Universal Noiseless Source Codes
Although the existence of universal noiseless variable-rate codes for the class of discrete stationary ergodic sources has previously been established, very few practical universal encoding methods are available. Efficient implementable universal source coding techniques are discussed in this paper. Results are presented on source codes for which a small value of the maximum redundancy is achieved with a relatively short block length. A constructive proof of the existence of universal noiseless codes for discrete stationary sources is first presented. The proof is shown to provide a method for obtaining efficient universal noiseless variable-rate codes for various classes of sources. For memoryless sources, upper and lower bounds are obtained for the minimax redundancy as a function of the block length of the code. Several techniques for constructing universal noiseless source codes for memoryless sources are presented and their redundancies are compared with the bounds. Consideration is given to possible applications to data compression for certain nonstationary sources
Local Energy
At a point in the future that is no longer remote, renewable energy will be a necessity. The construction of large renewable energy farms is central to a transition away from fossil fuels, but distributed renewable energy technologiesÂżwind turbines in backyards and solar panels on roofsÂżare immediately essential as well. Widespread deployment of distributed renewable technologies requires rapid innovation led by renewable energy pioneersÂżindividuals who act as market leaders and prove to their neighbors that these new energy devices are safe and worthy of use. This Article assesses the relative institutional capacities of different levels of government to determine which will best ensure that land-energy rules enable a drive toward distributed renewable energy and concludes that the powers of municipal governments must be unleashed
Local Energy
At a point in the future that is no longer remote, renewable energy will be a necessity. The construction of large renewable energy farms is central to a transition away from fossil fuels, but distributed renewable energy technologies—wind turbines in backyards and solar panels on roofs—are immediately essential as well. Widespread deployment of distributed renewable technologies requires rapid innovation led by renewable energy pioneers—individuals who act as market leaders and prove to their neighbors that these new energy devices are safe and worthy of use. Existing law and the very structure of governmental authority over energy is ill-suited to this energy transition and stifles the efforts of these pioneers. Public bodies must therefore embark upon a substantial overhaul of what we call land-energy rules—legal requirements governing the construction and physical location of renewable technology. This Article assesses the relative institutional capacities of different levels of government to determine which will best ensure that land-energy rules enable a drive toward distributed renewable energy and concludes that the powers of municipal governments must be unleashed. Innovation will occur from the ground up, and municipalities must actively work to enable the next great energy transition in this country: a move toward energy produced from the sun, the wind, the earth’s internal heat, and other renewable sources
Use of milk progesterone and PGF2α in a scheduled insemination program
Holstein cows milked twice daily were assigned to be inseminated at their first detected estrus (control) after 42 days in milk or received PGFza (PG) after 42 days, if they had a high milk progesterone (P4) test on any of 3 consecutive Mondays until first inseminated. Milk P4 tests and injections of PG were given on Mondays, and most of the breeding occurred on Thursdays and Fridays. The proportion of cows inseminated within 21 days of the beginning of the breeding period was greater in the milk P4 + PG group (52.8%) than in the control (38.9%). Compared to controls, use of PG reduced days to first service by 12.2 ± 3.1 d, calving intervals by 23.3 ± 8.9 d, rate of reproductive culling, and cost per pregnancy. We concluded that using PG as a management tool in an AI program is warranted and cost effective. However, the milk P4 test would not be justifiable unless its cost were significantly lower than the cost of a weekly injection of PG.; Dairy Day, 1993, Kansas State University, Manhattan, KS, 1993
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Search for Standard Model Higgs Boson in H ---> WW Channel at CDF
We present a search for standard model (SM) Higgs boson to WW{sup (*)} production in dilepton plus missing transverse energy final states in data collected by the CDF II detector corresponding to 4.8 fb{sup -1} of integrated luminosity. To maximize sensitivity, the multivariate discriminants used to separate signal from background in the opposite-sign dilepton event sample are independently optimized for final states with zero, one, or two or more identified jets. All significant Higgs boson production modes (gluon fusion, associated production with either a W or Z boson, and vector boson fusion) are considered in determining potential signal contributions. We also incorporate a separate analysis of the same-sign dilepton event sample which potentially contains additional signal events originating from associated Higgs boson production mechanisms. Cross section limits relative to the combined SM predictions are presented for a range of Higgs boson mass hypotheses between 110 and 200 GeV/c{sup 2}
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