314 research outputs found

    E-learning in knowledge-based society

    Get PDF
    The new training technologies can help improve the quality of the teaching and learning process, reduce training time and costs and compensate for the lack of training opportunities. One of the most prominent technologies is the development of Internet - leading to the development of e-learning. In the knowledge-based society, training stresses on individual learning and innovation to meet the restructuring of the industry. The Continuous Learning Centre (CLC) has demonstrated the success of the Internet learning and has been a pioneer in this area in Hong Kong. The experience and future development of CLC will be shared in this paper

    Probing neutral top-pion via a flavor-changing process γγtcˉΠt0\gamma\gamma\to t\bar{c}\Pi_{t}^{0}

    Full text link
    In the framework of topcolor-assisted-technicolor model(TC2), we study a flavor-changing neutral top-pion production process γγtcˉΠt0\gamma\gamma\to t\bar{c}\Pi_{t}^{0}. The study shows that there exists a resonance effect which can enhance the cross section up to a few fb even tens fb. For a yearly luminosity 100 fb1fb^{-1} at future linear colliders, there might be hundreds even thousands events to be produced. On the other hand, the background of such flavor-changing process is very clean due to the GIM mechanism in SM . With such sufficient events and clean background, neutral toppion could be detected at future linear colliders with high center of energy and luminosity. Our study provides a possible way to test TC2 model.Comment: 10 pages, 4 figures,has been accepted by Phys.Rev.

    Circadian control of white and brown adipose tissues

    Get PDF
    White and brown adipose tissues are highly dynamic organs anticipating and responding to changes in the environment. The circadian timing system facilitates anticipation, and it is therefore not surprising that circadian disturbances, a prominent feature of modern 24/7 society, increase the risk for (cardio)metabolic diseases. In this mini-review, we will address mechanisms and strategies to mitigate disease risk associated with circadian disturbances. In addition, we discuss the opportunities arising from the knowledge we gained about circadian rhythms in these adipose tissues, including the application of chronotherapy, optimizing endogenous circadian rhythms to allow for more effective intervention, and the identification of novel therapeutic targets.Metabolic health: pathophysiological trajectories and therap

    Associated production of neutral toppion with a pair of heavy quarks in γγ\gamma\gamma collisions

    Full text link
    We have studied a neutral toppion production process γγffˉΠt0(f=t,b)\gamma\gamma\to f\bar{f}\Pi_{t}^{0}(f=t,b) in the topcolor-assisted technicolor(TC2) model. We find that the cross section of γγttˉΠt0\gamma\gamma\to t\bar{t}\Pi_{t}^{0} is much larger than that of γγbbˉΠt0\gamma\gamma\to b\bar{b}\Pi_{t}^{0}. On the other hand, the cross section can be obviously enhanced with the increasing of c.m.energy. With s=1600\sqrt{s}=1600 GeV, the cross section of ttˉΠt0t\bar{t}\Pi_t^0 production can reach the level of a few fb. The results show that γγttˉΠt0ttˉ(tcˉ)\gamma\gamma\to t\bar{t}\Pi^0_t \to t\bar{t}(t\bar{c}) is the most ideal channel to detect neutral toppion due to the clean SM background. With such sufficient signals and clean background, neutral toppion could be detected at TESLA with high c.m.energy.Comment: 11 pages, 5 figure

    Enhancement of dark matter relic density from the late time dark matter conversions

    Full text link
    We demonstrate that if the dark matter (DM) in the Universe contains multiple components,the interactions between the DM components may induce DM conversions. It is then possible that the lightest DM component with an annihilation cross section much larger than that of the typical weakly interacting massive particle (WIMP) can obtain a relic density in consistent with the cosmological observations, due to an enhancement from the DM conversion process at late time after the thermal decoupling. This provides an alternative source of large boost factor required to explain the excesses reported by the recent DM indirect search experiments.Comment: 15 pages, 3 figures, version to appear in Eur.Phys.J.

    Prunella vulgaris: A comprehensive review of chemical constituents, pharmacological effects and clinical applications.

    Get PDF
    Prunella vulgaris (PV) is a perennial herb belonging to the Labiate family and is widely distributed in northeastern Asian countries such as Korea, Japan, and China. It is reported to display diverse biological activities including anti-microbial, anti-cancer, and anti-inflammation as determined by in vitro or in vivo studies. So far, about 200 compounds have been isolated from PV plant and majority of these have been characterized mainly as triterpenoids, sterols and flavonoids, followed by coumarins, phenylpropanoids, polysaccharides and volatile oils. This review summarizes and analyzes the current knowledge on the chemical constituents, pharmacological activities, mechanisms of action and clinical applications of the PV plant including its potential as a future medicinal plant. Although some of the chemical constituents of the PV plant and their mechanism of action have been investigated the biological activities of many of these remain unknown and further clinical trials are required to further enhance its reputation as a medicinal plant

    Search for electroweak production of single top quarks in ppˉp\bar{p} collisions.

    Get PDF
    We present a search for electroweak production of single top quarks in the electron+jets and muon+jets decay channels. The measurements use ~90 pb^-1 of data from Run 1 of the Fermilab Tevatron collider, collected at 1.8 TeV with the DZero detector between 1992 and 1995. We use events that include a tagging muon, implying the presence of a b jet, to set an upper limit at the 95% confidence level on the cross section for the s-channel process ppbar->tb+X of 39 pb. The upper limit for the t-channel process ppbar->tqb+X is 58 pb. (arXiv

    Measurement of the WW production cross section in p anti-p collisions at s**(1/2) = 1.96 TeV

    Get PDF
    We present a measurement of the W boson pair-production cross section in p anti-p collisions at a center-of-mass energy of sqrt{s}=1.96 TeV. The data, collected with the Run II DO detector, correspond to an integrated luminosity of 224-252 pb^-1 depending on the final state (ee, emu or mumu). We observe 25 candidates with a background expectation of 8.1+/-0.6(stat)+/-0.6(syst)+/-0.5(lum) events. The probability for an upward fluctuation of the background to produce the observed signal is 2.3x10^-7, equivalent to 5.2 standard deviations.The measurement yields a cross section of 13.8+4.3/-3.8(stat)+1.2/-0.9(syst)+/-0.9(lum) pb, in agreement with predictions from the standard model.Comment: submitted to PR

    Erratum to Measurement of σ(ppˉZ)Br(Zττ)\sigma (p \bar p \to Z) \cdot Br(Z \to \tau\tau) at s=\bm{\sqrt{s}=}1.96 TeV, published in Phys. Rev. D {71}, 072004 (2005)

    Full text link
    A change in estimated integrated luminosity (from 226 pb1to257pb^{-1} to 257 pb^{-1}leadstoacorrectedvaluefor leads to a corrected value for {\sigma (p \bar p \to Z) \cdot}BrBr{(Z \to \tau \tau)}of of 209\pm13(stat.)\pm16(syst.)\pm13(lum) pb

    Combination of searches for Higgs boson pairs in pp collisions at \sqrts = 13 TeV with the ATLAS detector

    Get PDF
    This letter presents a combination of searches for Higgs boson pair production using up to 36.1 fb(-1) of proton-proton collision data at a centre-of-mass energy root s = 13 TeV recorded with the ATLAS detector at the LHC. The combination is performed using six analyses searching for Higgs boson pairs decaying into the b (b) over barb (b) over bar, b (b) over barW(+)W(-), b (b) over bar tau(+)tau(-), W+W-W+W-, b (b) over bar gamma gamma and W+W-gamma gamma final states. Results are presented for non-resonant and resonant Higgs boson pair production modes. No statistically significant excess in data above the Standard Model predictions is found. The combined observed (expected) limit at 95% confidence level on the non-resonant Higgs boson pair production cross-section is 6.9 (10) times the predicted Standard Model cross-section. Limits are also set on the ratio (kappa(lambda)) of the Higgs boson self-coupling to its Standard Model value. This ratio is constrained at 95% confidence level in observation (expectation) to -5.0 &lt; kappa(lambda) &lt; 12.0 (-5.8 &lt; kappa(lambda) &lt; 12.0). In addition, limits are set on the production of narrow scalar resonances and spin-2 Kaluza-Klein Randall-Sundrum gravitons. Exclusion regions are also provided in the parameter space of the habemus Minimal Supersymmetric Standard Model and the Electroweak Singlet Model. For complete list of authors see http://dx.doi.org/10.1016/j.physletb.2019.135103</p
    corecore