11,084 research outputs found

    Cation mono- and co-doped anatase TiO2_2 nanotubes: An {\em ab initio} investigation of electronic and optical properties

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    The structural, electronic, and optical properties of metal (Si, Ge, Sn, and Pb) mono- and co-doped anatase TiO2_{2} nanotubes are investigated, in order to elucidate their potential for photocatalytic applications. It is found that Si doped TiO2_{2} nanotubes are more stable than those doped with Ge, Sn, or Pb. All dopants lower the band gap, except the (Ge, Sn) co-doped structure, the decrease depending on the concentration and the type of dopant. Correspondingly, a redshift in the optical properties for all kinds of dopings is obtained. Even though a Pb mono- and co-doped TiO2_{2} nanotube has the lowest band gap, these systems are not suitable for water splitting, due to the location of the conduction band edges, in contrast to Si, Ge, and Sn mono-doped TiO2_{2} nanotubes. On the other hand, co-doping of TiO2_{2} does not improve its photocatalytic properties. Our findings are consistent with recent experiments which show an enhancement of light absorption for Si and Sn doped TiO2_{2} nanotubes.Comment: revised and updated, 23 pages (preprint style), 7 figures, 5 table

    In an Attempt to Introduce Long-range Interactions into Small-world Networks

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    Distinguishing the long-range bonds with the regular ones, the critical temperature of the spin-lattice Guassian model built on two typical Small-world Networks (SWNs) is studied. The results show much difference from the classical case, and thus may induce some more accurate discussion on the critical properties of the spin-lattice systems combined with the SWNs.Comment: 4 pages, 3 figures, 18 referenc

    On determination of the geometric cosmological constant from the OPERA experiment of superluminal neutrinos

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    The recent OPERA experiment of superluminal neutrinos has deep consequences in cosmology. In cosmology a fundamental constant is the cosmological constant. From observations one can estimate the effective cosmological constant Λeff\Lambda_{eff} which is the sum of the quantum zero point energy Λdarkenergy\Lambda_{dark energy} and the geometric cosmological constant Λ\Lambda. The OPERA experiment can be applied to determine the geometric cosmological constant Λ\Lambda. It is the first time to distinguish the contributions of Λ\Lambda and Λdarkenergy\Lambda_{dark energy} from each other by experiment. The determination is based on an explanation of the OPERA experiment in the framework of Special Relativity with de Sitter space-time symmetry.Comment: 7 pages, no figure

    Predictions on the Development Dimensions of Provincial Tourism Discipline Based on the Artificial Neural Network BP Model

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    As the tourism industry has gradually become the strategic mainstay industry of the national economy, the scope of the tourism discipline has developed rigorously. This paper makes a predictive study on the development of the scope of Guangdong provincial tourism discipline based on the artificial neural network BP model in order to find out how the branch of tourism studies can better adapt to the development of the tourism industry. The research findings indicate that the BP model can be applied to the predictions of the scope of the tourism discipline and provide a quantitative basis for decision making with regard to the spatial layout and optimal allocation of the tourism discipline

    Peran Panti Sosial Dalam Membina Dan Meningkatkan Life Skills Anak Terlantar

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    The aim of this research was to explain the role of the orphanage in building and increasing the life skills for homeless children. The method used in this research was descriptive method with quantitative approach. The samples of this research were 50 children. The data were analyzed by using Chi quadrate and Questionnaire. The result showed that: there was a role of the orphanage to build and increase the life skills for homeless children in PSBR Radin Intan. This research proved that when the role of the orphanage more higher, so in building and increasing the life skills for homelsess children will be higher too.Tujuan penelitian ini untuk menjelaskan peran panti sosial dalam membina dan meningkatkan life skills anak kurang mampu dan terlantar di Pelayanan Sosial Bina Remaja (PSBR) Radin Intan. Metode penelitian yang digunakan dalam penelitian ini adalah metode deskriptif dengan pendekatan kuantitatif.Sampel dalam penelitian ini 50 orang. Analisis data menggunakan Chi Kuadrat dan teknik pengumpulan data menggunakan Angket. Hasil penelitian menunjukkan bahwa: terdapat peran panti sosial dalam membina dan meningkatkan life skills anak kurang mampu dan terlantar di Pelayanan Sosial Bina Remaja (PSBR) Radin Intan. Hal ini menunjukkan bahwa semakin tinggi peran panti sosial maka dalam membina dan meningkatkan life skills semakin tinggi juga

    Applicative Bidirectional Programming with Lenses

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    A bidirectional transformation is a pair of mappings between source and view data objects, one in each direction. When the view is modified, the source is updated accordingly with respect to some laws. One way to reduce the development and maintenance effort of bidirectional transformations is to have specialized languages in which the resulting programs are bidirectional by construction---giving rise to the paradigm of bidirectional programming. In this paper, we develop a framework for applicative-style and higher-order bidirectional programming, in which we can write bidirectional transformations as unidirectional programs in standard functional languages, opening up access to the bundle of language features previously only available to conventional unidirectional languages. Our framework essentially bridges two very different approaches of bidirectional programming, namely the lens framework and Voigtlander’s semantic bidirectionalization, creating a new programming style that is able to bag benefits from both

    WAP four-disulfide core domain protein 2 mediates the proliferation of human ovarian cancer cells through the regulation of growth- and apoptosis-associated genes.

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    The WAP four-disulfide core domain protein 2 (WFDC2) is frequently overexpressed in epithelial ovarian cancer cells and has been proposed as a potential biomarker. The biological function of WFDC2 in tumor progression remains unclear. In this study, the stable expression of short hairpin RNA (shRNA) against WFDC2 in the human ovarian SKOV3 cell line was established. Cell proliferation in vitro was determined by MTT assay. Cell cycle and apoptosis were analyzed by FACS. The expression of genes related to cell proliferation and survival was detected by real-time RT-PCR and western blotting. In vivo tumor growth assay was performed by establishing WFDC2-knockdown xenografts in nude mice and monitoring tumor growth. The expression of WFDC2, Ki67 and activated caspase-3 was analyzed by immunohistochemistry in order to determine the role of WFDC2 in proliferation and apoptosis. Our results revealed that the silencing of WFDC2 abolished ovarian cancer cell proliferation, suppressing tumor formation and growth in ovarian cancer cells both in vitro and in vivo. The knockdown of WFDC2 induced upregulation of Fasl and the downregulation of cyclin D1 activated caspase-3 and Ki67. These results indicate that WFDC2 plays a crucial role in tumor formation and growth in ovarian cancer cells. WFDC2 may be a potential therapeutic target for epithelial ovarian cancer

    Specific-heat study of superconducting and normal states in FeSe1-xTex (0.6<=x<=1) single crystals: Strong-coupling superconductivity, strong electron-correlation, and inhomogeneity

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    The electronic specific heat of as-grown and annealed single-crystals of FeSe1-xTex (0.6<=x<=1) has been investigated. It has been found that annealed single-crystals with x=0.6-0.9 exhibit bulk superconductivity with a clear specific-heat jump at the superconducting (SC) transition temperature, Tc. Both 2Delta_0/kBTc [Delta_0: the SC gap at 0 K estimated using the single-band BCS s-wave model] and Delta C/(gamma_n-gamma_0)Tc [Delta C$: the specific-heat jump at Tc, gamma_n: the electronic specific-heat coefficient in the normal state, gamma_0: the residual electronic specific-heat coefficient at 0 K in the SC state] are largest in the well-annealed single-crystal with x=0.7, i.e., 4.29 and 2.76, respectively, indicating that the superconductivity is of the strong coupling. The thermodynamic critical field has also been estimated. gamma_n has been found to be one order of magnitude larger than those estimated from the band calculations and increases with increasing x at x=0.6-0.9, which is surmised to be due to the increase in the electronic effective mass, namely, the enhancement of the electron correlation. It has been found that there remains a finite value of gamma_0 in the SC state even in the well-annealed single-crystals with x=0.8-0.9, suggesting an inhomogeneous electronic state in real space and/or momentum space.Comment: 22 pages, 1 table, 6 figures, Version 2 has been accepted for publication in J. Phys. Soc. Jp

    Relating Leptogenesis to Low Energy Flavor Violating Observables in Models with Spontaneous CP Violation

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    In the minimal left-right symmetric model, there are only two intrinsic CP violating phases to account for all CP violation in both the quark and lepton sectors, if CP is broken spontaneously by the complex phases in the VEV's of the scalar fields. In addition, the left- and right-handed Majorana mass terms for the neutrinos are proportional to each other due to the parity in the model. This is thus a very constrained framework, making the existence of correlations among the CP violation in leptogenesis, neutrino oscillation and neutrinoless double beta decay possible. In these models, CP violation in the leptonic sector and CP violation in the quark sector are also related. We find, however, that such connection is rather weak due to the large hierarchy in the bi-doublet VEV required by a realistic quark sector.Comment: RevTeX4, 21 pages; v2: references added, version to appear in Phys. Rev.
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