3,053 research outputs found
The Cosmic Ray Observatory Project: A Statewide Outreach and Education Experiment in Nebraska
The Cosmic Ray Observatory Project (CROP) is a statewide education and
research experiment involving Nebraska high school students, teachers and
university undergraduates in the study of extensive cosmic-ray air showers. A
network of high school teams construct, install, and operate school-based
detectors in coordination with University of Nebraska physics professors and
graduate students. The detector system at each school is an array of
scintillation counters recycled from the Chicago Air Shower Array in
weather-proof enclosures on the school roof, with a GPS receiver providing a
time stamp for cosmic-ray events. The detectors are connected to triggering
electronics and a data-acquisition PC inside the building. Students share data
via the Internet to search for time coincidences with other sites. Funded by
the National Science Foundation, CROP has enlisted 29 schools with the aim of
expanding to the 314 high schools in the state over several years. This report
highlights both the scientific and professional development achievements of the
project to date.Comment: 4 pages, 4 figures, submitted to the 2007 International Cosmic Ray
Conference (ICRC2007), Merida, Mexico, July 200
TraĆŸenje Higgsa i supersimetrije tevatronom
Results are presented of searches for Standard Model and MSSM Higgs, as well as supersymmetric particles. A broad variety of signatures were explored by the CDF and DĂ experiments, using approximately 2 fbâ1 of reconstructed ppÂŻ data from collisions at 1.96 TeV at Fermilabâs Tevatron. No significant deviation from background sources has been observed in any of the searches, and new limits have been set on the production cross sections.Predstavljamo ishode traĆŸenja Higgsa i supersimetriÄnih Äestica prema standardnom modelu i prema MSSM. Primjenjuje se ĆĄiroka lepeza znakova u CDF i DĂ eksperimentima, rabeÄi oko 2 fbâ1 analiziranih podataka za ppÂŻ sudare na 1.96 TeV u Tevatronu Fermilab-a. U tim traĆŸenjima nismo naĆĄli odstupanja od ĆĄuma, i postavili smo nove granice za udarne presjeke
Attribute abstraction, feature-dimensionality, and the scaling of product similarities
This paper examines the attributes that consumers use when making product similarity judgments and their effect on similarity scaling. Previous research suggests that concrete brands are judged using dichotomous features while more abstract product categories are judged using continuous dimensions. This, in turn, suggests that the appropriateness of spatial scaling increases relative to tree scaling as one moves from brands to product categories. The results of two studies support an increase in the fit of spaces relative to trees from brands to categories. However, the abstractness of the judgments appears to be driving the effect, not the use of features or dimensions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30067/1/0000437.pd
Search for a Fourth Generation tl Quark in ppÌ Collisions at âs= 1.96 TeV
We present a search for pair production of a fourth generation tl quark and its antiparticle, followed by their decays to a W boson and a jet, based on an integrated luminosity of 5.3 fb-1 of proton-antiproton collisions at âs= 1.96 TeV collected by the D0 Collaboration at the Fermilab Tevatron Collider. We set upper limits on the tlt-l production cross section that exclude at the 95% C.L. a tl quark that decays exclusively to W + jet with a mass below 285 GeV. We observe a small excess in the ” + jets channel which reduces the mass range excluded compared to the expected limit of 320 GeV in the absence of a signal
Wy Production and Limits on Anomalous WWy Couplings in ppÌ Collisions âs = 1.96 TeV
We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W(â lv) + y production in ey and ”y final states. Using data corresponding to an integrated luminosity of 4.2 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider, the measured cross section times branching fraction for the process ppÌ
â Wy + X â lvy + X and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WW[1] couplings for data from hadron colliders: -0.4 \u3c âky \u3c 0.4 and -0.08 \u3c λy \u3c 0.07 at the 95% C.L
Evidence for Simultaneous Production of J/Ï and Ï Mesons
We report evidence for the simultaneous production of J/Ï and Ï mesons in 8.1 fbâ1 of data collected at âs = 1.96 TeV by the D0 experiment at the Fermilab pÂŻp Tevatron Collider. Events with these characteristics are expected to be produced predominantly by gluon-gluon interactions. In this analysis, we extract the effective cross section characterizing the initial parton spatial distribution, Ïeff = 2.2 ± 0.7(stat) ± 0.9(syst) mb
Wy Production and Limits on Anomalous WWy Couplings in ppÌ Collisions âs = 1.96 TeV
We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W(â lv) + y production in ey and ”y final states. Using data corresponding to an integrated luminosity of 4.2 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider, the measured cross section times branching fraction for the process ppÌ
â Wy + X â lvy + X and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WW[1] couplings for data from hadron colliders: -0.4 \u3c âky \u3c 0.4 and -0.08 \u3c λy \u3c 0.07 at the 95% C.L
Search for a Fermiophobic and Standard Model Higgs Boson in Diphoton Final States
We present a search for the standard model Higgs boson and a fermiophobic Higgs boson in the diphoton final states based on 8.2 fb-1 of ppÌ
collisions at âs= 1.96 TeV collected with the D0 detector at the Fermilab Tevatron Collider. No excess of data above background predictions is observed and upper limits at the 95% C.L. on the cross section multiplied by the branching fraction are set which are the most restrictive to date. A fermiophobic Higgs boson with a mass below 112.9 GeV is excluded at the 95% C.L
<i>Trypanosoma evansi</i>: Genetic variability detected using amplified restriction fragment length polymorphism (AFLP) and random amplified polymorphic DNA (RAPD) analysis of Kenyan isolates
We compared two methods to generate polymorphic markers to investigate the population genetics of Trypanosoma evansi; random amplified polymorphic DNA (RAPD) and amplified restriction fragment length polymorphism (AFLP) analyses. AFLP accessed many more polymorphisms than RAPD. Cluster analysis of the AFLP data showed that 12 T.evansi isolates were very similar (âtype Aâ) whereas 2 isolates differed substantially (âtype Bâ). Type A isolates have been generally regarded as genetically identical but AFLP analysis was able to identify multiple differences between them and split the type A T. evansi isolates into two distinct clades
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