1,867 research outputs found

    A Semantic Grid Oriented to E-Tourism

    Full text link
    With increasing complexity of tourism business models and tasks, there is a clear need of the next generation e-Tourism infrastructure to support flexible automation, integration, computation, storage, and collaboration. Currently several enabling technologies such as semantic Web, Web service, agent and grid computing have been applied in the different e-Tourism applications, however there is no a unified framework to be able to integrate all of them. So this paper presents a promising e-Tourism framework based on emerging semantic grid, in which a number of key design issues are discussed including architecture, ontologies structure, semantic reconciliation, service and resource discovery, role based authorization and intelligent agent. The paper finally provides the implementation of the framework.Comment: 12 PAGES, 7 Figure

    Proteomic analysis of the rat ovary following chronic low-dose exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

    Get PDF
    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a ubiquitously distributed endocrine-disrupting chemical and reproductive toxicant. In order to elucidate low-dose TCDD-mediated effects on reproductive or endocrine functions, female Sprague-Dawley rats were orally administered various concentrations (20, 50, or 125 ng/kg once weekly) TCDD for 29 wk. A proteomic analysis of the ovaries by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization (MALDI) tandem mass spectrometry showed distinct changes in the levels of several proteins that are relevant markers of TCDD toxicity. Serum estradiol (E2) levels of TCDD-treated animals were markedly lower than control. There were no significant differences in bone mineral density (BMD) of femurs. The body weight of the 125-ng/kg TCDD group was significantly decreased relative to control and there was also a significant reduction in absolute and relative ovarian weights. Expressions of selenium binding protein 2, glutathione S-transferase mu type 3, Lrpap1 protein, NADPH, and peptidylprolyl isomerase D were upregulated, while prohibitin and N-ethylmaleimide-sensitive factor expression levels were downregulated. Data provide further insight into the mechanisms by which TCDD disrupts ovarian function by indicating which differential protein expressions following low-dose TCDD exposure

    NARROMI: a noise and redundancy reduction technique improves accuracy of gene regulatory network inference.

    Get PDF
    MOTIVATION: Reconstruction of gene regulatory networks (GRNs) is of utmost interest to biologists and is vital for understanding the complex regulatory mechanisms within the cell. Despite various methods developed for reconstruction of GRNs from gene expression profiles, they are notorious for high false positive rate owing to the noise inherited in the data, especially for the dataset with a large number of genes but a small number of samples. RESULTS: In this work, we present a novel method, namely NARROMI, to improve the accuracy of GRN inference by combining ordinary differential equation-based recursive optimization (RO) and information theory-based mutual information (MI). In the proposed algorithm, the noisy regulations with low pairwise correlations are first removed by using MI, and the redundant regulations from indirect regulators are further excluded by RO to improve the accuracy of inferred GRNs. In particular, the RO step can help to determine regulatory directions without prior knowledge of regulators. The results on benchmark datasets from Dialogue for Reverse Engineering Assessments and Methods challenge and experimentally determined GRN of Escherichia coli show that NARROMI significantly outperforms other popular methods in terms of false positive rates and accuracy. AVAILABILITY: All the source data and code are available at: http://csb.shu.edu.cn/narromi.htm

    Energy, interaction, and photoluminescence of spin-reversed quasielectrons in fractional quantum Hall systems

    Full text link
    The energy and photoluminescence spectra of a two-dimensional electron gas in the fractional quantum Hall regime are studied. The single-particle properties of reversed-spin quasielectrons (QER_{\rm R}'s) as well as the pseudopotentials of their interaction with one another and with Laughlin quasielectrons (QE's) and quasiholes (QH's) are calculated. Based on the short-range character of the QER_{\rm R}--QER_{\rm R} and QER_{\rm R}--QE repulsion, the partially unpolarized incompressible states at the filling factors ν=411\nu={4\over11} and 513{5\over13} are postulated within Haldane's hierarchy scheme. To describe photoluminescence, the family of bound h(h(QER)n_{\rm R})_n states of a valence hole hh and nn QER_{\rm R}'s are predicted in analogy to the found earlier fractionally charged excitons hhQEn_n. The binding energy and optical selection rules for both families are compared. The hhQER_{\rm R} is found radiative in contrast to the dark hhQE, and the h(h(QER)2_{\rm R})_2 is found non-radiative in contrast to the bright hhQE2_2.Comment: 9 pages, 6 figure

    Analysis of the doubly heavy baryons in the nuclear matter with the QCD sum rules

    Full text link
    In this article, we study the doubly heavy baryon states Ξcc\Xi_{cc}, Ωcc\Omega_{cc}, Ξbb\Xi_{bb} and Ωbb\Omega_{bb} in the nuclear matter using the QCD sum rules, and derive three coupled QCD sum rules for the masses, vector self-energies and pole residues. The predictions for the mass-shifts in the nuclear matter ΔMΞcc=1.11GeV\Delta M_{\Xi_{cc}}=-1.11\,\rm{GeV}, ΔMΩcc=0.33GeV\Delta M_{\Omega_{cc}}=-0.33\,\rm{GeV}, ΔMΞbb=3.37GeV\Delta M_{\Xi_{bb}}=-3.37\,\rm{GeV} and ΔMΩbb=1.05GeV\Delta M_{\Omega_{bb}}=-1.05\,\rm{GeV} can be confronted with the experimental data in the future.Comment: 10 pages, 4 figure

    Quantum Ferromagnetism and Phase Transitions in Double-Layer Quantum Hall Systems

    Full text link
    Double layer quantum Hall systems have interesting properties associated with interlayer correlations. At ν=1/m\nu =1/m where mm is an odd integer they exhibit spontaneous symmetry breaking equivalent to that of spin 1/21/2 easy-plane ferromagnets, with the layer degree of freedom playing the role of spin. We explore the rich variety of quantum and finite temperature phase transitions in these systems. In particular, we show that a magnetic field oriented parallel to the layers induces a highly collective commensurate-incommensurate phase transition in the magnetic order.Comment: 4 pages, REVTEX 3.0, IUCM93-013, 1 FIGURE, hardcopy available from: [email protected]

    Running coupling: Does the coupling between dark energy and dark matter change sign during the cosmological evolution?

    Full text link
    In this paper we put forward a running coupling scenario for describing the interaction between dark energy and dark matter. The dark sector interaction in our scenario is free of the assumption that the interaction term QQ is proportional to the Hubble expansion rate and the energy densities of dark sectors. We only use a time-variable coupling b(a)b(a) (with aa the scale factor of the universe) to characterize the interaction QQ. We propose a parametrization form for the running coupling b(a)=b0a+be(1a)b(a)=b_0a+b_e(1-a) in which the early-time coupling is given by a constant beb_e, while today the coupling is given by another constant, b0b_0. For investigating the feature of the running coupling, we employ three dark energy models, namely, the cosmological constant model (w=1w=-1), the constant ww model (w=w0w=w_0), and the time-dependent ww model (w(a)=w0+w1(1a)w(a)=w_0+w_1(1-a)). We constrain the models with the current observational data, including the type Ia supernova, the baryon acoustic oscillation, the cosmic microwave background, the Hubble expansion rate, and the X-ray gas mass fraction data. The fitting results indicate that a time-varying vacuum scenario is favored, in which the coupling b(z)b(z) crosses the noninteracting line (b=0b=0) during the cosmological evolution and the sign changes from negative to positive. The crossing of the noninteracting line happens at around z=0.20.3z=0.2-0.3, and the crossing behavior is favored at about 1σ\sigma confidence level. Our work implies that we should pay more attention to the time-varying vacuum model and seriously consider the phenomenological construction of a sign-changeable or oscillatory interaction between dark sectors.Comment: 8 pages, 5 figures; refs added; to appear in EPJ

    The σ\sigma pole in J/ψωπ+πJ/\psi \to \omega \pi^+ \pi^-

    Full text link
    Using a sample of 58 million J/ψJ/\psi events recorded in the BESII detector, the decay J/ψωπ+πJ/\psi \to \omega \pi^+ \pi^- is studied. There are conspicuous ωf2(1270)\omega f_2(1270) and b1(1235)πb_1(1235)\pi signals. At low ππ\pi \pi mass, a large broad peak due to the σ\sigma is observed, and its pole position is determined to be (541±39)(541 \pm 39) - ii (252±42)(252 \pm 42) MeV from the mean of six analyses. The errors are dominated by the systematic errors.Comment: 15 pages, 6 figures, submitted to PL

    Measurements of Cabibbo Suppressed Hadronic Decay Fractions of Charmed D0 and D+ Mesons

    Full text link
    Using data collected with the BESII detector at e+ee^{+}e^{-} storage ring Beijing Electron Positron Collider, the measurements of relative branching fractions for seven Cabibbo suppressed hadronic weak decays D0KK+D^0 \to K^- K^+, π+π\pi^+ \pi^-, KK+π+πK^- K^+ \pi^+ \pi^- and π+π+ππ\pi^+ \pi^+ \pi^- \pi^-, D+K0ˉK+D^+ \to \bar{K^0} K^+, KK+π+K^- K^+ \pi^+ and ππ+π+\pi^- \pi^+ \pi^+ are presented.Comment: 11 pages, 5 figure
    corecore