3,580 research outputs found

    Physics Potential of Very Intense Conventional Neutrino Beams

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    The physics potential of high intensity conventional beams is explored. We consider a low energy super beam which could be produced by a proposed new accelerator at CERN, the Super Proton Linac. Water Cherenkov and liquid oil scintillator detectors are studied as possible candidates for a neutrino oscillation experiment which could improve our current knowledge of the atmospheric parameters and measure or severely constrain the parameter connecting the atmospheric and solar realms. It is also shown that a very large water detector could eventually observe leptonic CP violation. The reach of such an experiment to the neutrino mixing parameters would lie in-between the next generation of neutrino experiments (MINOS, OPERA, etc) and a future neutrino factory.Comment: Talk given at the Venice Conference on Neutrino Telescopes, Venice, March, 200

    Brain-specific tropomyosins TMBr-1 and TMBr-3 have distinct patterns of expression during development and in adult brain

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    In this study we report on the developmental and regional expression of two brain-specific isoforms of tropomyosin, TMBr-1 and TMBr-3, that are generated from the rat alpha-tropomyosin gene via the use of alternative promoters and alternative RNA splicing. Western blot analysis using an exon-specific peptide polyclonal antibody revealed that the two isoforms are differentially expressed in development with TMBr-3 appearing in the embryonic brain at 16 days of gestation, followed by the expression of TMBr-1 at 20 days after birth. TMBr-3 was detected in all brain regions examined, whereas TMBr-1 was detected predominantly in brain areas that derived from the prosencephalon. Immunocytochemical studies on mixed primary cultures made from rat embryonic midbrain indicate that expression of the brain-specific epitope is restricted to neurons. The developmental pattern and neuronal localization of these forms of tropomyosin suggest that these isoforms have a specialized role in the development and plasticity of the nervous system

    Genetic instrumental variable regression: Explaining socioeconomic and health outcomes in nonexperimental data

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    Identifying causal effects in nonexperimental data is an enduring challenge. One proposed solution that recently gained popularity is the idea to use genes as instrumental variables [i.e., Mendelian randomization (MR)]. However, this approach is problematic because many variables of interest are genetically correlated, which implies the possibility that many genes could affect both the exposure and the outcome directly or via unobserved confounding factors. Thus, pleiotropic effects of genes are themselves a source of bias in nonexperimental data that would also undermine the ability of MR to correct for endogeneity bias from nongenetic sources. Here, we propose an alternative approach, genetic instrumental variable (GIV) regression, that provides estimates for the effect of an exposure on an outcome in the presence of pleiotropy. As a valuable byproduct, GIV regression also provides accurate estimates of the chip heritability of the outcome variable. GIV regression uses polygenic scores (PGSs) for the outcome of interest which can be constructed from genome-wide association study (GWAS) results. By splitting the GWAS sample for the outcome into nonoverlapping subsamples, we obtain multiple indicators of the outcome PGSs that can be used as instruments for each other and, in combination with other methods such as sibling fixed effects, can address endogeneity bias from both pleiotropy and the environment. In two empirical applications, we demonstrate that our approach produces reasonable estimates of the chip heritability of educational attainment (EA) and show that standard regression and MR provide upwardly biased estimates of the effect of body height on EA

    Cowpeas - A New Forage Crop for South Dakota

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    In the northern Great Plains, cool-season pastures decline in productivity during summer. This reduces available forage supplies. Solutions to forage shortages during the summer traditionally have included the use of perennial and annual warm-season species for pastures, hay, or silage. Cowpeas, a non-traditional crop suitable for summer forage, have been investigated recently at SDSU. Cowpeas (Vigna unguiculata [L.] Walp.) are an important legume in the southeastern United States, but since 1940 they have been replaced gradually by soybeans, clovers, and other legumes. Referred to as “black-eyed peas,” cowpeas are grown primarily for human consumption but also are suitable for hay, silage, and pasture

    Pilot testing of a novel surgical simulator for endoscopic zenker’s diverticulotomy

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136304/1/lary26129.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136304/2/lary26129_am.pd

    A study of atmospheric neutrinos with the IMB detector

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    A sample of 401 contained neutrino interactions collected in the 3300 metric ton fiducial mass IMB detector was used to study neutrino oscillations, geomagnetic modulation of the flux and to search for point sources. The majority of these events are attributed to neutrino interactions. For the most part, these neutrinos are believed to originate as tertiary products of cosmic ray interactions in the atmosphere. The neutrinos are a mixture of v sub e and v sub micron

    Neutrino oscillation physics with a higher γ\gamma β\beta-beam

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    The precision measurement and discovery potential of a neutrino factory based on a storage ring of boosted radioactive ions (β\beta-beam) is re-examined. In contrast with past designs, which assume ion γ\gamma factors of 100\sim 100 and baselines of L=130 km, we emphasize the advantages of boosting the ions to higher γ\gamma and increasing the baseline proportionally. In particular, we consider a medium-γ\gamma scenario (γ500\gamma \sim 500, L=730 km) and a high-γ\gamma scenario (γ2000\gamma \sim 2000, L = 3000 km).The increase in statistics, which grow linearly with the average beam energy, the ability to exploit the energy dependence of the signal and the sizable matter effects at this longer baseline all increase the discovery potential of such a machine very significantly.Comment: An error corrected, conclusions unchanged. Revised version to appear in Nuclear Physics

    Analytic Results for the Gravitational Radiation from a Class of Cosmic String Loops

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    Cosmic string loops are defined by a pair of periodic functions a{\bf a} and b{\bf b}, which trace out unit-length closed curves in three-dimensional space. We consider a particular class of loops, for which a{\bf a} lies along a line and b{\bf b} lies in the plane orthogonal to that line. For this class of cosmic string loops one may give a simple analytic expression for the power γ\gamma radiated in gravitational waves. We evaluate γ\gamma exactly in closed form for several special cases: (1) b{\bf b} a circle traversed MM times; (2) b{\bf b} a regular polygon with NN sides and interior vertex angle π2πM/N\pi-2\pi M/N; (3) b{\bf b} an isosceles triangle with semi-angle θ\theta. We prove that case (1) with M=1M=1 is the absolute minimum of γ\gamma within our special class of loops, and identify all the stationary points of γ\gamma in this class.Comment: 15 pages, RevTex 3.0, 7 figures available via anonymous ftp from directory pub/pcasper at alpha1.csd.uwm.edu, WISC-MILW-94-TH-1

    Off-diagonal structure of neutrino mass matrix in see-saw mechanism and electron-muon-tau lepton universality

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    By a simple extension of the standard model in which (eμτe-\mu -\tau ) universality is not conserved, we present a scenario within the framework of see-saw mechanism in which the neutrino mass matrix is strictly off-diagonal in the flavor basis. We show that a version of this scenario can accomodate the atmospheric νμντ\nu_\mu -\nu_\tau neutrino oscillations and νμνe\nu_\mu -\nu_e oscillations claimed by the LSND collaboration. PACS: 14.60.Pq; 14.60.St;13.15.+gComment: 5 pages, Revtex, 1 figure: The model accomodate another version which explains atmospheric neutrino data and the observed solar neutrino oscillations (large angle solution). In the previous version the value of \lambda parameter is changed to the expected one. This version now accomodates LSND result and solar neutrino oscillations (small angle MSW solution
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