157 research outputs found

    The Bactrocera (Notodacus) xanthodes (Broun) Species Complex (Diptera: Tephritidae): Comparison of 18S rRNA Sequences from Fiji, Tonga and Vanuatu Specimens Suggest Two Distinct Strains

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    Preliminary data suggest that fly specimens from Fiji, Tonga and Vanuatu presently classified as Bactrocera (Notodacus) xanthodes (Broun) show significant divergence at the 18S ribosomal RNA gene level. Sequencing data indicate that the Vanuatu specimen may be considered a strain separate from that on Fiji and Tonga

    Importance of fundamental movement skills to predict technical skills in youth grassroots soccer:a machine learning approach

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    This study determined the contributors to soccer technical skill in grassroots youth soccer players using a machine learning approach. One hundred and sixty two boys aged 7-14 (Mean ± SD = 10.5 ± 2.1) years, who were regularly engaged in grassroots soccer undertook assessments of anthropometry and maturity offset (the time from age at peak height velocity (APHV)), Fundamental Movement skills (FMS), perceived physical competence, and physical fitness and technical soccer skill using the university of Ghent (UGent) dribbling test. Coaches rated player’s overall soccer skill for their age. Statistical analysis was undertaken, using machine learning models to predict technical skill from the other variables. A stepwise recursive feature elimination with a 5-fold cross-validation (RFECV) method was used to eliminate the worst performing features and both L1 and L2 regularisation were evaluated during the process. Five models (linear, ridge, lasso, random forest, boosted trees) were then used in a heuristic approach using a small subset of suitable algorithms to achieve a reasonable level of accuracy within a reasonable time frame) to make predictions and compare them to a test set to understand the predictive capabilities of the models. Results from the machine learning analysis indicated that total FMS score (0-50) was the most important feature in predicting technical soccer skill followed by coach rating of child skill for their age, years playing experience and APHV. Using a random forest, technical skill could be predicted with 99% accuracy in boys who play grassroots soccer, with FMS being the most important contributor

    The Structure of TGBC_C Phases

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    We study the transition from the cholesteric phase to two TGBC_C phases near the upper critical twist kc2k_{c2}: the Renn-Lubensky TGBC_C phase, with layer normal rotating in a plane perpendicular to the pitch axis, and the Bordeaux TGBC_C phase, with the layer normal rotating on a cone parallel to the pitch axis. We calculate properties, including order-parameter profiles, of both phases.Comment: 4 pages, 4 figures, Submitted to Physical Review E, Rapid Communications, September 5, 2003; Revised manuscript (to the paper submitted on March 18, 2003, cond-mat/0303365)that includes an important missing reference and presents an improved analysis of a generalized mode

    Conflicts and management styles in the Sri Lankan commercial building sector

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    The Sri Lankan commercial building industry is currently experiencing a construction boom after thirty years of civil war. Creating a dispute free environment through well conflict management is one of the main ways to keep the continuous demand and development of construction. However, the Sri Lankan construction sector is arranged in such a way that they directly approach the dispute resolution rather than avoiding the dispute initially through proper conflict management. The aim of this research is to understand the prevailing conflict management styles in Sri Lankan commercial building industry from the main stakeholders’ perspective. The dual concern theory is applied to this study as a theory foundation. Four cases are selected for this study with the intention of conducting meetings with three main stakeholders of each case who represented client, consultants and contractors respectively. The research findings reveal that compromising is the most common conflict management style used by the industry. Forcing style obtained the second place in the ranking whereas obliging and avoiding received third and fourth places. This study is conducted to provide a full picture of conflicts faced by the Sri Lankan commercial building industry and their proper management so that the future projects will use this information to diminish the destructive effects of conflict situations and provide a real value for money. Key Words: Conflict Management; Dual Concern Theory; Commercial Building Sector; Sri Lank

    Evolution and Flare Activity of Delta-Sunspots in Cycle 23

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    The emergence and magnetic evolution of solar active regions (ARs) of beta-gamma-delta type, which are known to be highly flare-productive, were studied with the SOHO/MDI data in Cycle 23. We selected 31 ARs that can be observed from their birth phase, as unbiased samples for our study. From the analysis of the magnetic topology (twist and writhe), we obtained the following results. i) Emerging beta-gamma-delta ARs can be classified into three topological types as "quasi-beta", "writhed" and "top-to-top". ii) Among them, the "writhed" and "top-to-top" types tend to show high flare activity. iii) As the signs of twist and writhe agree with each other in most cases of the "writhed" type (12 cases out of 13), we propose a magnetic model in which the emerging flux regions in a beta-gamma-delta AR are not separated but united as a single structure below the solar surface. iv) Almost all the "writhed"-type ARs have downward knotted structures in the mid portion of the magnetic flux tube. This, we believe, is the essential property of beta-gamma-delta ARs. v) The flare activity of beta-gamma-delta ARs is highly correlated not only with the sunspot area but also with the magnetic complexity. vi) We suggest that there is a possible scaling-law between the flare index and the maximum umbral area

    A geometric approach to time evolution operators of Lie quantum systems

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    Lie systems in Quantum Mechanics are studied from a geometric point of view. In particular, we develop methods to obtain time evolution operators of time-dependent Schrodinger equations of Lie type and we show how these methods explain certain ad hoc methods used in previous papers in order to obtain exact solutions. Finally, several instances of time-dependent quadratic Hamiltonian are solved.Comment: Accepted for publication in the International Journal of Theoretical Physic

    Higgs Boson Decay into Hadronic Jets

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    The remarkable agreement of electroweak data with standard model (SM) predictions motivates the study of extensions of the SM in which the Higgs boson is light and couples in a standard way to the weak gauge bosons. Postulated new light particles should have small couplings to the gauge bosons. Within this context it is natural to assume that the branching fractions of the light SM-like Higgs boson mimic those in the standard model. This assumption may be unwarranted, however, if there are non-standard light particles coupled weakly to the gauge bosons but strongly to the Higgs field. In particular, the Higgs boson may effectively decay into hadronic jets, possibly without important bottom or charm flavor content. As an example, we present a simple extension of the SM, in which the predominant decay of the Higgs boson occurs into a pair of light bottom squarks that, in turn, manifest themselves as hadronic jets. Discovery of the Higgs boson remains possible at an electron-positron linear collider, but prospects at hadron colliders are diminished substantially.Comment: 30 pages, 7 figure

    Measurement of the Atmospheric Muon Spectrum from 20 to 3000 GeV

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    The absolute muon flux between 20 GeV and 3000 GeV is measured with the L3 magnetic muon spectrometer for zenith angles ranging from 0 degree to 58 degree. Due to the large exposure of about 150 m2 sr d, and the excellent momentum resolution of the L3 muon chambers, a precision of 2.3 % at 150 GeV in the vertical direction is achieved. The ratio of positive to negative muons is studied between 20 GeV and 500 GeV, and the average vertical muon charge ratio is found to be 1.285 +- 0.003 (stat.) +- 0.019 (syst.).Comment: Total 32 pages, 9Figure

    Measurements of long-range near-side angular correlations in sNN=5\sqrt{s_{\text{NN}}}=5TeV proton-lead collisions in the forward region

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    Two-particle angular correlations are studied in proton-lead collisions at a nucleon-nucleon centre-of-mass energy of sNN=5\sqrt{s_{\text{NN}}}=5TeV, collected with the LHCb detector at the LHC. The analysis is based on data recorded in two beam configurations, in which either the direction of the proton or that of the lead ion is analysed. The correlations are measured in the laboratory system as a function of relative pseudorapidity, Δη\Delta\eta, and relative azimuthal angle, Δϕ\Delta\phi, for events in different classes of event activity and for different bins of particle transverse momentum. In high-activity events a long-range correlation on the near side, Δϕ0\Delta\phi \approx 0, is observed in the pseudorapidity range 2.0<η<4.92.0<\eta<4.9. This measurement of long-range correlations on the near side in proton-lead collisions extends previous observations into the forward region up to η=4.9\eta=4.9. The correlation increases with growing event activity and is found to be more pronounced in the direction of the lead beam. However, the correlation in the direction of the lead and proton beams are found to be compatible when comparing events with similar absolute activity in the direction analysed.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-040.htm

    Study of the production of Λb0\Lambda_b^0 and B0\overline{B}^0 hadrons in pppp collisions and first measurement of the Λb0J/ψpK\Lambda_b^0\rightarrow J/\psi pK^- branching fraction

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    The product of the Λb0\Lambda_b^0 (B0\overline{B}^0) differential production cross-section and the branching fraction of the decay Λb0J/ψpK\Lambda_b^0\rightarrow J/\psi pK^- (B0J/ψK(892)0\overline{B}^0\rightarrow J/\psi\overline{K}^*(892)^0) is measured as a function of the beauty hadron transverse momentum, pTp_{\rm T}, and rapidity, yy. The kinematic region of the measurements is pT<20 GeV/cp_{\rm T}<20~{\rm GeV}/c and 2.0<y<4.52.0<y<4.5. The measurements use a data sample corresponding to an integrated luminosity of 3 fb13~{\rm fb}^{-1} collected by the LHCb detector in pppp collisions at centre-of-mass energies s=7 TeV\sqrt{s}=7~{\rm TeV} in 2011 and s=8 TeV\sqrt{s}=8~{\rm TeV} in 2012. Based on previous LHCb results of the fragmentation fraction ratio, fΛB0/fdf_{\Lambda_B^0}/f_d, the branching fraction of the decay Λb0J/ψpK\Lambda_b^0\rightarrow J/\psi pK^- is measured to be \begin{equation*} \mathcal{B}(\Lambda_b^0\rightarrow J/\psi pK^-)= (3.17\pm0.04\pm0.07\pm0.34^{+0.45}_{-0.28})\times10^{-4}, \end{equation*} where the first uncertainty is statistical, the second is systematic, the third is due to the uncertainty on the branching fraction of the decay B0J/ψK(892)0\overline{B}^0\rightarrow J/\psi\overline{K}^*(892)^0, and the fourth is due to the knowledge of fΛb0/fdf_{\Lambda_b^0}/f_d. The sum of the asymmetries in the production and decay between Λb0\Lambda_b^0 and Λb0\overline{\Lambda}_b^0 is also measured as a function of pTp_{\rm T} and yy. The previously published branching fraction of Λb0J/ψpπ\Lambda_b^0\rightarrow J/\psi p\pi^-, relative to that of Λb0J/ψpK\Lambda_b^0\rightarrow J/\psi pK^-, is updated. The branching fractions of Λb0Pc+(J/ψp)K\Lambda_b^0\rightarrow P_c^+(\rightarrow J/\psi p)K^- are determined.Comment: 29 pages, 19figures. All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-032.htm
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