2,423 research outputs found
Measurements of Single W Production at LEP2
In the energy region of LEP2 and above, four fermion final states in e+e-
collisions can be produced by Feynman diagrams involving two, one or zero
resonant bosons...Comment: 4 pages, 2 figures, presented at LEPTRE, XIII Convegno sulla Fisica
al LEP, ROma, 200
Bose-Einstein Correlations in W-pair events at LEP
An overview of measurements of Bose-Einstein correlations in W-pair events at LEP is given. The results presented are based on data collected at centre-of-mass energies between 172 and 202GeV. The review concentrates on the search for Bose-Einstein correlations between pions from different W's in e+e- -> W+W- -> qqbarqqbar events. No agreement is reached in the results of the four experiments
MDT data quality assessment at the Calibration Centres for the ATLAS experiment at LHC
ATLAS is a large multipurpose detector, presently in the final phase of construction at the CERN Large Hadron Collider accelerator. In ATLAS the muon detection is performed by a huge magnetic spectrometer, built with the Monitored Drift Tube technology. It consists of more than 1,000 chambers and 350,000 drift tubes, which have to be controlled to a spatial accuracy better than 10 μm and an efficiency close to 100%. Therefore, the automated monitoring of the detector is an essential aspect of the operation of the spectrometer. The quality procedure collects data from online and offline sources and from the Calibration Stream at the Calibration Centres, situated in Ann Arbor (Michigan), MPI (Munich) and INFN Rome. The assessment at the Calibration Centres is performed using the DQHistogramAnalyzer utility of the ATHENA package. This application checks the histograms in an automated way and, after a further inspection with a human interface, reports results and summaries. The analysis results are stored in an Oracle Database using the COOL LCG library, through a C++ object-oriented interface. In this study a complete description of the entire chain, from the calibration stream up to the database storage is presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/85418/1/jpconf10_219_032062.pd
DNA profiling, telomere analysis and antioxidant properties as tools for monitoring ex situ seed longevity
Background and Aims The germination test currently represents the most used method to assess seed viability in germplasm banks, despite the difficulties caused by the occurrence of seed dormancy. Furthermore, seed longevity can vary considerably across species and populations from different environments and studies related to the eco-physiological processes underlying such variations are still limited in their depth. The aim of the present work was the identification of reliable molecular markers that might help monitoring seed deterioration.
Methods Dry seeds were subjected to artificial aging and collected at different time points for molecular/biochemical analyses. DNA damage was measured using the RAPD (Random Amplified Polymorphic DNA) approach while the seed antioxidant profile was obtained using both the DPPH (1,1-diphenyl, 2-picrylhydrazyl) assay and the Folin Ciocalteu reagent method. Electron Paramagnetic Resonance (EPR) provided profiles of free radicals. Quantitative RealTime-Polymerase Chain Reaction (QRT-PCR) was used to assess the expression profiles of the antioxidant genes MT2 (Type 2 Metallothionein) and SOD (Superoxide Dismutase). A modified QRT-PCR protocol was used to determine telomere length.
Key Results The RAPD profiles highlighted different capacities of the two Silene species to overcome DNA damage induced by artificial aging. The antioxidant profiles of dry and rehydrated seeds revealed that the high-altitude taxon Silene acaulis was characterised by a lower antioxidant specific activity. Significant up-regulation of the MT2 and SOD genes was observed only in the rehydrated seeds of the low-altitude species. Rehydration resulted in telomere lengthening in both Silene species.
Conclusions Different seed viability markers have been selected for plant species showing inherent variation of seed longevity. RAPD analysis, quantification of redox activity of non enzymatic antioxidant compounds and gene expression profiling provide deeper insights to study seed viability during storage. Telomere lengthening is a promising tool to discriminate between short- and long-lived species
Isotopic composition (238U/235U) of some commonly used uranium reference materials
We have determined 238U/235U ratios for a suite of commonly used natural (CRM 112a, SRM 950a, and HU-1) and synthetic (IRMM 184 and CRM U500) uranium reference materials by thermal ionisation mass-spectrometry (TIMS) using the IRMM 3636 233U-236U double spike to accurately correct for mass fractionation. Total uncertainty on the 238U/235U determinations is estimated to be < 0.02% (2σ). These natural 238U/235U values are different from the widely used ‘consensus’ value (137.88), with each standard having lower 238U/235U values by up to 0.08%. The 238U/235U ratio determined for CRM U500 and IRMM 184 are within error of their certified values; however, the total uncertainty for CRM U500 is substantially reduced (from 0.1% to 0.02%). These reference materials are commonly used to assess mass spectrometer performance and accuracy, calibrate isotope tracers employed in U, U-Th and U-Pb isotopic studies, and as a reference for terrestrial and meteoritic 238U/235U variations. These new 238U/235U values will thus provide greater accuracy and reduced uncertainty for a wide variety of isotopic determinations
Reestablishment of Performance Management System of Headquarter of F Provincial Expressway Company
企业要走向市场,立足于市场,就要参与市场竞争,要在市场上处于不败之地,就要有先进的管理机制与管理理念,不断壮大完善自己,提高自身竞争力。而企业提高自身竞争力的有效途径之一是进行基于战略的绩效管理,通过实施绩效管理在经营过程中实现投入产出最优化,夯实利润增长的基础,所以建立有效的绩效管理体系对于全面提升公司的竞争能力,具有十分重要的现实意义。同时,企业内外部环境的变化使得企业的管理需求更加多样化,进而进一步加大了绩效管理实施的难度。如何保证绩效管理不仅适应企业实际,同时适时反映企业内外部环境变化,也就成了当前理论界和企业界面临的新课题。 我国自上世纪八十年代末开始兴建高速公路,1988年12月...The enterprises have to participate in competition in order to enter and to base on market. Whether an enterprise can remain invincible for a long time depends on equipping with advanced management system and idea, continuously improving and enhancing the market competitiveness. One of the effective ways to enhance the competitiveness is to carry out the strategy-based performance management, opti...学位:工商管理硕士院系专业:管理学院工商管理教育中心(MBA中心)_工商管理硕士(MBA)学号:1792007115056
EFTfitter: A tool for interpreting measurements in the context of effective field theories
Over the past years, the interpretation of measurements in the context of effective field theories has attracted much attention in the field of particle physics. We present a tool for interpreting sets of measurements in such models using a Bayesian ansatz by calculating the posterior probabilities of the corresponding free parameters numerically. An example is given, in which top-quark measurements are used to constrain anomalous couplings at the Wtb-vertex.The authors would like to thank Fabian Bach, Kathrin Becker, Dominic Hirschbühl and Mikolaj Misiak for their help and for the fruitful discussions. In particular, the authors would like to thank Fabian Bach for providing the code for the single-top cross sections. N.C. acknowledges the support of FCT-Portugal through the contract IF/00050/2013/CP1172/CT00
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