20,608 research outputs found

    Z0Z_0 Boson Decays to Bc(∗)B^{(*)}_c Meson and Its Uncertainties

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    The programming new e+e−e^{+}e^- collider with high luminosity shall provide another useful platform to study the properties of the doubly heavy BcB_c meson in addition to the hadronic colliders as LHC and TEVATRON. Under the `New Trace Amplitude Approach', we calculate the production of the spin-singlet BcB_c and the spin-triplet Bc∗B^*_c mesons through the Z0Z^0 boson decays, where uncertainties for the production are also discussed. Our results show Γ(1S0)=81.4−40.5+102.1\Gamma_{(^1S_0)}= 81.4^{+102.1}_{-40.5} KeV and Γ(3S1)=116.4−62.8+163.9\Gamma_{(^3S_1)}=116.4^{+163.9}_{-62.8} KeV, where the errors are caused by varying mbm_b and mcm_c within their reasonable regions.Comment: 11 pages, 5 figures, 2 tables. To be published in Eur.Phys.J.

    Development and implementation of Taiwan\u27s child health literacy test

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    Objectives: The aims of this study were to develop Taiwan\u27s Child Health Literacy Test and to undertake a nation-wide survey in order to determine the current status of Taiwanese sixth graders\u27 health literacy, and to understand the association between health literacy, healthy behavior, and health status. absp Methods: Taiwan\u27s Child Health Literacy Test was developed through the process of concept clarification, a qualitative pilot, a development pilot, and a field test. In the field test, 162,609 sixth graders (56.9%) from 2,235 schools (83.3%) nationwide completed the questionnaire. We also collected the students\u27 dates of birth, BMIs, self-reported health and healthy behaviors. absp Results: The final test consisted of 32 questions with item discrimination of 0.55-1.89 and item difficulty of-1.7-0.41 according to IRT; Cronbach\u27s a was 0.87. Based on this information, the test was deemed appropriate for basic health literacy screening among children. Nation-wide, the average score for sixth graders\u27 health literacy was 23.97 points (total score 32 points), with a correct rate of 74.9%. Those who were "good" in self-reported health scored highest in health literacy (M = 24.29). Health literacy was significantly positively related to healthy behavior (r = .25, p< .05), and negatively to risky behavior (r =-.28, p< .05). absp Conclusions: This study was the first curriculum-based child health literacy test developed from the viewpoints of both teachers and pupils in Taiwan through a rigorous procedure. The nationwide survey results may serve as a reference for decision-makers at the national health education level

    Controlling Excitations Inversion of a Cooper Pair Box Interacting with a Nanomechanical Resonator

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    We investigate the action of time dependent detunings upon the excitation inversion of a Cooper pair box interacting with a nanomechanical resonator. The method employs the Jaynes-Cummings model with damping, assuming different decay rates of the Cooper pair box and various fixed and t-dependent detunings. It is shown that while the presence of damping plus constant detunings destroy the collapse/revival effects, convenient choices of time dependent detunings allow one to reconstruct such events in a perfect way. It is also shown that the mean excitation of the nanomechanical resonator is more robust against damping of the Cooper pair box for convenient values of t-dependent detunings.Comment: 11 pages, 5 figure

    Controlled formation of metallic nanowires via Au nanoparticle ac trapping

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    Applying ac voltages, we trapped gold nanoparticles between microfabricated electrodes under well-defined conditions. We demonstrate that the nanoparticles can be controllably fused together to form homogeneous gold nanowires with pre-defined diameters and conductance values. Whereas electromigration is known to form a gap when a dc voltage is applied, this ac technique achieves the opposite, thereby completing the toolkit for the fabrication of nanoscale junctions.Comment: Nanotechnology 18, 235202 (2007

    Stability of a neural network model with small-world connections

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    Small-world networks are highly clustered networks with small distances among the nodes. There are many biological neural networks that present this kind of connections. There are no special weightings in the connections of most existing small-world network models. However, this kind of simply-connected models cannot characterize biological neural networks, in which there are different weights in synaptic connections. In this paper, we present a neural network model with weighted small-world connections, and further investigate the stability of this model.Comment: 4 pages, 3 figure

    Production and Decay of the Ge73-m Metastable State in a Low-Background Germanium Detector

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    The ≥73m\ge73m metastable states decay with a very characteristic signature which allow them to be tagged event-by-event. Studies were performed using data taken with a high-purity germanium detector in a low-background laboratory near a nuclear power reactor core where \nuebar-flux was 6.4×1012 cm−2s−1\rm{6.4 \times 10^{12} ~ cm^{-2} s^{-1}}. The measured average and equilibrium production rates of ≥73m\ge73m were (8.7±0.4)\rm{(8.7 \pm 0.4)} and (6.7±0.3) kg−1day−1\rm{(6.7 \pm 0.3) ~ kg^{-1} day^{-1}}, respectively. The production channels were studied and identified. By studying the difference in the production of ≥73m\ge73m between the reactor ON and OFF spectra, the limiting sensitivities at the range of ∼10−42−10−43 cm2\rm{\sim 10^{-42} - 10^{-43} ~ cm^2} for the cross-sections of neutrino-induced nuclear transitions were derived. The dominant background are due to β\beta-decays of cosmic-ray induced 73^{73}Ga. The prospects of enhancing the sensitivities at underground locations are discussed.Comment: 16 pages, 10 figure
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