119 research outputs found

    Relações morfométricas para árvores dominantes de Pinus taeda no Estado do Paraná.

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    Este trabalho objetivou estudar as relações morfométricas de árvores dominantes de Pinus taeda no município de Ponta Grossa, Paraná. Em cada amostra a árvore de maior diâmetro a altura do peito (DAP) foi considerada dominante em relação às suas vizinhas. Destas foram mensuradas dap, altura total, altura da copa e oito raios de copa. As variáveis morfométricas analisadas foram: diâmetro de copa, altura da copa, proporção de copa, grau de esbeltez, índice de saliência, índice de abrangência e formal de copa. Estas foram correlacionadas com o dap e altura através de correlação de Pearson. De acordo com os índices, as árvores analisadas possuem média instabilidade, copas arredondadas e não há necessidade de desbaste na área. O diâmetro a altura do peito se correlacionou melhor com as variáveis morfométricas estudadas, indicando que estas sofrem alterações conforme as árvores incrementam em diâmetro

    Measurement of the Pion Form Factor in the Energy Range 1.04-1.38 GeV with the CMD-2 Detector

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    The cross section for the process e+e−→π+π−e^+e^-\to\pi^+\pi^- is measured in the c.m. energy range 1.04-1.38 GeV from 995 000 selected collinear events including 860000 e+e−e^+e^- events, 82000 μ+μ−\mu^+\mu^- events, and 33000 π+π−\pi^+\pi^- events. The systematic and statistical errors of measuring the pion form factor are equal to 1.2-4.2 and 5-13%, respectively.Comment: 5 pages, 2 figure

    VaRank: a simple and powerful tool for ranking genetic variants:

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    Background. Most genetic disorders are caused by single nucleotide variations (SNVs) or small insertion/deletions (indels). High throughput sequencing has broadened the catalogue of human variation, including common polymorphisms, rare variations or disease causing mutations. However, identifying one variation among hundreds or thousands of others is still a complex task for biologists, geneticists and clinicians. Results. We have developed VaRank, a command-line tool for the ranking of genetic variants detected by high-throughput sequencing. VaRank scores and prioritizes variants annotated either by Alamut Batch or SnpEff. A barcode allows users to quickly view the presence/absence of variants (with homozygote/heterozygote status) in analyzed samples. VaRank supports the commonly used VCF input format for variants analysis thus allowing it to be easily integrated into NGS bioinformatics analysis pipelines. VaRank has been successfully applied to disease-gene identification as well as to molecular diagnostics setup for several hundred patients. Conclusions. VaRank is implemented in Tcl/Tk, a scripting language which is platform-independent but has been tested only on Unix environment. The source code is available under the GNU GPL, and together with sample data and detailed documentation can be downloaded from http://www.lbgi.fr/VaRank/

    The Muon Anomalous Magnetic Moment and the Standard Model

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    The muon anomalous magnetic moment measurement, when compared with theory, can be used to test many extensions to the standard model. The most recent measurement made by the Brookhaven E821 Collaboration reduces the uncertainty on the world average of a_mu to 0.7 ppm, comparable in precision to theory. This paper describes the experiment and the current theoretical efforts to establish a correct standard model reference value for the muon anomaly.Comment: Plenary Talk; PANIC'02 XVI Particles and Nuclear International Conference, Osaka, Japan; Sept. 30 - Oct. 4, 2002; Report describes the published 0.7 ppm result and updates the theory statu

    Final Report of the Muon E821 Anomalous Magnetic Moment Measurement at BNL

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    We present the final report from a series of precision measurements of the muon anomalous magnetic moment, a_mu = (g-2)/2. The details of the experimental method, apparatus, data taking, and analysis are summarized. Data obtained at Brookhaven National Laboratory, using nearly equal samples of positive and negative muons, were used to deduce a_mu(Expt) = 11 659 208.0(5.4)(3.3) x 10^-10, where the statistical and systematic uncertainties are given, respectively. The combined uncertainty of 0.54 ppm represents a 14-fold improvement compared to previous measurements at CERN. The standard model value for a_mu includes contributions from virtual QED, weak, and hadronic processes. While the QED processes account for most of the anomaly, the largest theoretical uncertainty, ~0.55 ppm, is associated with first-order hadronic vacuum polarization. Present standard model evaluations, based on e+e- hadronic cross sections, lie 2.2 - 2.7 standard deviations below the experimental result.Comment: Summary paper of E821 Collaboration measurements of the muon anomalous magnetic moment, each reported earlier in Letters or Brief Reports; 96 pages, 41 figures, 16 tables. Revised version submitted to PR

    Search for Lorentz and CPT Violation Effects in Muon Spin Precession

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    The spin precession frequency of muons stored in the (g−2)(g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for: a nonzero Δωa\Delta\omega_{a} (=ωaμ+−ωaμ−\omega_{a}^{\mu^{+}}-\omega_{a}^{\mu^{-}}); and a sidereal variation of ωaμ±\omega_{a}^{\mu^{\pm}}. No significant effect is found, and the following limits on the standard-model extension parameters are obtained: bZ=−(1.0±1.1)×10−23b_{Z} =-(1.0 \pm 1.1)\times 10^{-23} GeV; (mμdZ0+HXY)=(1.8±6.0×10−23)(m_{\mu}d_{Z0}+H_{XY}) = (1.8 \pm 6.0 \times 10^{-23}) GeV; and the 95% confidence level limits bˇ⊥μ+<1.4×10−24\check{b}_{\perp}^{\mu^{+}}< 1.4 \times 10^{-24} GeV and bˇ⊥μ−<2.6×10−24\check{b}_{\perp}^{\mu^{-}} < 2.6 \times 10^{-24} GeV.Comment: 5 pages, 3 figures, submitted to Physical Review Letters, Modified to answer the referees suggestion

    Improved Measurement of the Positive Muon Anomalous Magnetic Moment

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    A new measurement of the positive muon's anomalous magnetic moment has been made at the Brookhaven Alternating Gradient Synchrotron using the direct injection of polarized muons into the superferric storage ring. The angular frequency difference omega_{a} between the angular spin precession frequency omega_{s} and the angular orbital frequency omega_{c} is measured as well as the free proton NMR frequency omega_{p}. These determine R = omega_{a} / omega_{p} = 3.707~201(19) times 10^{-3}. With mu_{mu} / mu_{p} = 3.183~345~39(10) this gives a_{mu^+} = 11~659~191(59) times 10^{-10} (pm 5 ppm), in good agreement with the previous CERN and BNL measurements for mu^+ and mu^-, and with the standard model prediction.Comment: 4 pages, 4 figures. accepted for publication in Phys. Rev. D62 Rapid Communication

    An Improved Limit on the Muon Electric Dipole Moment

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    Three independent searches for an electric dipole moment (EDM) of the positive and negative muons have been performed, using spin precession data from the muon g-2 storage ring at Brookhaven National Laboratory. Details on the experimental apparatus and the three analyses are presented. Since the individual results on the positive and negative muon, as well as the combined result, d=-0.1(0.9)E-19 e-cm, are all consistent with zero, we set a new muon EDM limit, |d| < 1.9E-19 e-cm (95% C.L.). This represents a factor of 5 improvement over the previous best limit on the muon EDM.Comment: 19 pages, 15 figures, 7 table
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