235 research outputs found

    Bayesian Analysis of Transition Model for Longitudinal Ordinal Response Data: Application to Insomnia Data

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    In this paper, we present a Bayesian framework for analyzing longitudinal ordinal response data. In analyzing longitudinal data, the possibility of correlations between responses given by the same individual needs to be taken into account. Various models can be used to handle such correlations such as marginal modeling, random effect modeling and transition (Markov) modeling. Here a transition modeling is used and a Bayesian approach is presented for analyzing longitudinal data. A cumulative logistic regression model and the Bayesian method, using MCMC, are implemented for obtaining the parameters estimates. Our approach is applied on a two-period longitudinal Insomnia data where the Bayesian estimate for measure of association, , between the initial and follow-up ordinal responses is obtained in each level of a treatment variable. Then, the sensitivity of posterior summaries to changes of prior hyperparameters is investigated. We also use Bayes factor criterion for testing some important hypotheses

    Environmental and strategic assessment of ecotourism potential in Anzali Wetland using SWOT analysis

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    SWOT analysis is used extensively as an assessment and planning method, particularly in tourism planning. However, there are little documentations on application of SWOT analysis in ecotourism. An assessment on systematic use of SWOT analysis was carried out in the present study to highlight the applicability of the SWOT technique in detailed investigations. In this study, based on field surveys and questionnaires (on Anzali Wetland and the local population), matrix of internal and external factors (threats, opportunities, weaknesses and strength) influencing tourism development in Anzali Wetland were evaluated within the framework of SWOT analysis and SO, WO, ST and WT strategies were identified. Based on the obtained results, the total score of 3.22 in IFE matrix suggests good condition of the system and high internal strength of the tourism development related to internal factors and the final score of 2.93 in the EFE matrix represents poor condition related to the external factors which means external factors have not been utilized properly; Thus appropriate planning and organizational management practices are required to deal with these factors. The study further proposes solutions, operational priorities and strategic planning according to environmental and local conditions of Anzali Wetland. Since the tourism industry in Iran is still in its early stages, particularly in Anzali Wetland region, the findings could help decision makers to estimate better the weaknesses, strengths, threats and opportunities, and to develop tourism industry in the region

    DBI with Primordial Magnetic Field in the Sky

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    In this paper, we study the generation of a large scale magnetic field with amplitude of order μ\muG in an inflationary model which has been introduced in hep-th/0310221. This inflationary model based on existence of a speed limit for inflaton field. Generating a mass for inflaton at scale above the ϕIR\phi_{IR}, breaks the conformal triviality of the Maxwell equation and causes to originate a magnetic field during the inflation. The amplitude strongly depends on the details of reheating stage and also depends on the e-foldings parameter N. We find the amplitude of the primordial magnetic field at decoupling time in this inflationary background using late time behavior of the theory.Comment: 12 pages, no figure, typos correcte

    Multiple Dp_p-branes as a Dp+2_{p+2}-brane

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    From BFSS matrix theory considerations, it is expected that a single Dp+2_{p+2}-brane action can be obtained from N Dp_p-brane action in large N limit. We examine and confirm this expectation by working out the details of DBI and Chern-Simons terms of Dp+2_{p+2}-brane action from Dp_{p}-brane action. We show that the same relation works for non-BPS, as well as BPS branesComment: 14 page

    M2-Branes and Background Fields

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    We discuss the coupling of multiple M2-branes to the background 3-form and 6-form gauge fields of eleven-dimensional supergravity, including the coupling of the Fermions. In particular we show in detail how a natural generalization of the Myers flux-terms, along with the resulting curvature of the background metric, leads to mass terms in the effective field theory.Comment: 19 page

    Synthesis and characterization of Sm2(MoO4)3, Sm2(MoO4)3/GO and Sm2(MoO4)3/C3N4 nanostructures for improved photocatalytic performance and their anti-cancer the MCF-7 cells

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    Samarium molybdate nanoparticles (Sm2(MoO4)3) were prepared through a hydrothermal procedure and were used to form various composites with graphene oxide (GO) and carbon nitride (C3N4). The changes in the dimensions and morphology of the products were prepared using template agents like cetyltrimethyl ammonium bromide (CTAB), Sodium dodecyl sulfate (SDS) (�90), Triton X-100 (90), Polyvinyl alcohol (95), Ethylene glycol (�99), and polyvinylpyrrolidone (PVP). DRS analysis indicated band gap for the Sm2(MoO4), Sm2(MoO4)3/GO, and Sm2(MoO4)3/C3N4 as 3.75, 3.15, and 3.4 respectively. The characteristics of the prepared nanostructures were studied through X-ray diffraction (XRD), energy dispersive X-ray (EDX), and scanning electron microscopy (SEM). Finally, the activity of the prepared Sm2(MoO4)3 as photo-catalysts for the degradation of different organic dyes such as methyl orange (MO), methylene blue (MB), and rhodamine B (Rh B) was evaluated. The photocatalytic property of Sm2(MoO4)3/C3N4 and Sm2(MoO4)3/GO for the degradation of MO, was obtained. Based on the empirical data Sm2(MoO4)3/C3N4 had the strongest photodegradation effect as compared to the other compounds tested after around 40 min. BET analysis revealed that the specific surface area of the Sm2(MoO4)3 nanocomposite prepared using C3N4 is 15 times that of in the absence of C3N4. Also, the cytotoxicity of synthesized samples was evaluated using MTT assay against human cell lines MCF-7 (cancer), and its IC50 was about 125 mg/L. © 202

    Preparation and characterization of magnetic Fe3O4/CdWO4 and Fe3O4/CdWO4/PrVO4 nanoparticles and investigation of their photocatalytic and anticancer properties on PANC1 cells

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    Fe3O4/CdWO4 and Fe3O4/CdWO4/PrVO4 magnetic nanoparticles were prepared at different molar ratios of PrVO4 to previous layers (Fe3O4/CdWO4) via the co-precipitation method assisted by a sonochemical procedure, in order to investigate the photocatalytic performance of these systems and their cytotoxicity properties. The physico-chemical properties of these magnetic nanoparticles were determined via several experimental methods: X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier transformation infrared spectroscopy and ultraviolet-visible diffuse reflection spectroscopy, using a vibrating sample magnetometer and a scanning electron microscope. The average sizes of these nanoparticles were found to be in the range of 60-100 nm. The photocatalytic efficiency of the prepared nanostructures was measured by methylene blue degradation under visible light (assisted by H2O2). The magnetic nanosystem with a 1:2:1 ratio of three oxide components showed the best performance by the degradation of ca. 70 after 120 min of exposure to visible light irradiation. Afterwards, this sample was used for the photodegradation of methyl orange, methyl violet, fenitrothion, and rhodamine-B pollutants. Finally, the mechanism of the photocatalytic reaction was examined by releasing �OH under UV light in a system including terephthalic acid, as well as O2-, OH, and hole scavengers. Additionally, the cytotoxicity of each synthesized sample was assessed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay against the human cell line PANC1 (cancer), and its IC50 was approximately 125 mg/L. © 2019 by the authors

    Coupling between M2-branes and Form Fields

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    In the context of low-energy effective theory of multiple M2-branes, we construct the interaction terms between the world-volume fields of M2-branes and the antisymmetric tensor fields of three- and six-forms. By utilizing the compactification procedure, we show coincidence between the dimensionally reduced coupling and the R-R coupling to D-branes in type II string theory. We also discuss that a cubic term proportional to six-form field reproduces the quartic mass-deformation term in the world-volume theory of multiple M2-branes.Comment: 18 page
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