1,095 research outputs found

    Research Note, June 1981

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    This is issue 17: Some Economic Aspects of the Deadwood Harvest on the Bitterroot National Foresthttps://scholarworks.umt.edu/montana_forestry_notes/1015/thumbnail.jp

    Economic Analysis of Wildlife Management Costs in the U.S. Forest Service, Northern Region

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    Paper published as Bulletin 47 in the UM Bulletin Forestry Series.https://scholarworks.umt.edu/umforestrybulletin/1030/thumbnail.jp

    Characterising the vertical separation of shale-gas source rocks and aquifers across England and Wales (UK)

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    Shale gas is considered by many to have the potential to provide the UK with greater energy security, economic growth and jobs. However, development of a shale gas industry is highly contentious due to environmental concerns including the risk of groundwater pollution. Evidence suggests that the vertical separation between exploited shale units and aquifers is an important factor in the risk to groundwater from shale gas exploitation. A methodology is presented to assess the vertical separation between different pairs of aquifers and shales that are present across England and Wales. The application of the method is then demonstrated for two of these pairs—the Cretaceous Chalk Group aquifer and the Upper Jurassic Kimmeridge Clay Formation, and the Triassic sandstone aquifer and the Carboniferous Bowland Shale Formation. Challenges in defining what might be considered criteria for ‘safe separation’ between a shale gas formation and an overlying aquifer are discussed, in particular with respect to uncertainties in geological properties, aquifer extents and determination of socially acceptable risk levels. Modelled vertical separations suggest that the risk of aquifer contamination from shale exploration will vary greatly between shale–aquifer pairs and between regions and this will need to be considered carefully as part of the risk assessment and management for any shale gas development

    Results from a Fermilab neutrino beam dump experiment

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    The flux of prompt neutrinos from a beam dump has been measured in an experiment at the Fermi National Accelerator Laboratory (E613). Assuming that the charm production has a linear dependence on atomic number and varies as (1−‖×‖)5 e−2mT, a model dependent cross section of 27±5μb/nucleon can be derived. For neutrino energies greater than 20 GeV, the flux of electron neutrinos with respect to muon neutrinos is 0.78±0.19. For neutrinos with energy greater than 30 GeV and p⟂ greater than 0.2, the flux of ν̄u compared to νμ is 0.96±0.22.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87363/2/100_1.pd

    Prompt Neutrino Results from Fermi Lab

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    Results from a Fermi lab experiment to study prompt neutrino production are presented. Assuming the prompt neutrinos come from the decay of charmed mesons we find a total DD production cross section of approx. 20 μb/nucleon, in good agreement with previous CERN results. We find a ν/ν ratio and a νe/νμ of approx. 1.0. The energy and pT spectra of the prompt neutrinos are consistent with those expected from DD production. Limits on the production of supersymmetric particles have also been obtained.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87356/2/262_1.pd

    Temporo-Spatial Dynamics of Event-Related EEG Beta Activity during the Initial Contingent Negative Variation

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    In the electroencephalogram (EEG), early anticipatory processes are accompanied by a slow negative potential, the initial contingent negative variation (iCNV), occurring between 500 and 1500 ms after cue onset over prefrontal cortical regions in tasks with cue-target intervals of about 3 s or longer. However, the temporal sequence of the distributed cortical activity contributing to iCNV generation remains unclear. During iCNV generation, selectively enhanced low-beta activity has been reported. Here we studied the temporal order of activation foci in cortical regions assumed to underlie iCNV generation using source reconstruction of low-beta (13–18 Hz) activity. During the iCNV, elicited by a cued simple reaction-time task, low-beta power peaked first (750 ms after cue onset) in anterior frontal and limbic regions and last (140 ms later) in posterior areas. This activity occurred 3300 ms before target onset and provides evidence for the temporally ordered involvement of both cognitive-control and motor-preparation processes already at early stages during the preparation for speeded action

    Efficiency of Finding Muon Track Trigger Primitives in CMS Cathode Strip Chambers

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    In the CMS Experiment, muon detection in the forward direction is accomplished by cathode strip chambers~(CSC). These detectors identify muons, provide a fast muon trigger, and give a precise measurement of the muon trajectory. There are 468 six-plane CSCs in the system. The efficiency of finding muon trigger primitives (muon track segments) was studied using~36 CMS CSCs and cosmic ray muons during the Magnet Test and Cosmic Challenge~(MTCC) exercise conducted by the~CMS experiment in~2006. In contrast to earlier studies that used muon beams to illuminate a very small chamber area (< ⁣0.01< \! 0.01~m2^2), results presented in this paper were obtained by many installed CSCs operating {\em in situ} over an area of  ⁣23\approx \! 23~m2^2 as a part of the~CMS experiment. The efficiency of finding 2-dimensional trigger primitives within 6-layer chambers was found to be~99.93±0.03%99.93 \pm 0.03\%. These segments, found by the CSC electronics within 800800~ns after the passing of a muon through the chambers, are the input information for the Level-1 muon trigger and, also, are a necessary condition for chambers to be read out by the Data Acquisition System

    Measurement of associated Z plus charm production in proton-proton collisions at root s=8TeV

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    A study of the associated production of a Z boson and a charm quark jet (Z + c), and a comparison to production with a b quark jet (Z + b), in pp collisions at a centre-of-mass energy of 8 TeV are presented. The analysis uses a data sample corresponding to an integrated luminosity of 19.7 fb(-1), collected with the CMS detector at the CERN LHC. The Z boson candidates are identified through their decays into pairs of electrons or muons. Jets originating from heavy flavour quarks are identified using semileptonic decays of c or b flavoured hadrons and hadronic decays of charm hadrons. The measurements are performed in the kinematic region with two leptons with pT(l) > 20 GeV, vertical bar eta(l)vertical bar 25 GeV and vertical bar eta(jet)vertical bar Z + c + X) B(Z -> l(+)l(-)) = 8.8 +/- 0.5 (stat)+/- 0.6 (syst) pb. The ratio of the Z+c and Z+b production cross sections is measured to be sigma(pp -> Z+c+X)/sigma (pp -> Z+b+X) = 2.0 +/- 0.2 (stat)+/- 0.2 (syst). The Z+c production cross section and the cross section ratio are also measured as a function of the transverse momentum of theZ boson and of the heavy flavour jet. The measurements are compared with theoretical predictions.Peer reviewe
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