114 research outputs found

    Understanding the Intrinsic Motivations of User Acceptance of Hedonic Information Systems: Towards a Unified Research Model

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    Although user acceptance of entertainment-oriented information systems (IS), which are called Hedonic IS (HIS), has drawn considerable attention in literature, our understanding of user acceptance of HIS is still limited. This article focuses on exploring the intrinsic motivations of HIS acceptance from a unique perspective. It proposes a hybrid HIS acceptance model that considers the unique characteristics of HIS and the multiple conceptual identities of an HIS user. The model integrates intrinsic motivation factors from Hedonic theory, Flow theory, and the PAD (Pleasure, Arousal, and Dominance) emotion model with the Technology Acceptance Model. The proposed hybrid HIS acceptance model has been empirically tested by a quantitative field survey. The results indicate that emotional responses, imaginal responses, and flow experience are three main predictors of HIS acceptance

    Generalized transfer matrix theory on electronic transport through graphene waveguide

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    In the effective mass approximation, electronic property in graphene can be characterized by the relativistic Dirac equation. Within such a continuum model we investigate the electronic transport through graphene waveguides formed by connecting multiple segments of armchair-edged graphene nanoribbons of different widths. By using appropriate wavefunction connection conditions at the junction interfaces, we generalize the conventional transfer matrix approach to formulate the linear conductance of the graphene waveguide in terms of the structure parameters and the incident electron energy. In comparison with the tight-binding calculation, we find that the generalized transfer matrix method works well in calculating the conductance spectrum of a graphene waveguide even with a complicated structure and relatively large size. The calculated conductance spectrum indicates that the graphene waveguide exhibits a well-defined insulating band around the Dirac point, even though all the constituent ribbon segments are gapless. We attribute the occurrence of the insulating band to the antiresonance effect which is intimately associated with the edge states localized at the shoulder regions of the junctions. Furthermore, such an insulating band can be sensitively shifted by a gate voltage, which suggests a device application of the graphene waveguide as an electric nanoswitch.Comment: 11 pages, 5 figure

    Risk Factors of Suicide Ideation in Chinese Graduate Students: CHAID Tree Analysis

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    The present study aims to identify the risk factors and develop a decision tree model of suicide ideation in Chinese graduate students. A chi-square automatic interaction detection tree analysis was conducted in a graduate students sample (N=1036). Measurements included University Personality Inventory (UPI), Symptom Checklist 90 (SCL-90), and Eysenck Personality Questionnaire (EPQ). Results showed that suicide incidence of Chinese graduate students was 1.15%, with males’ was higher than females. Seventeen potential variables were considered and only three of them (depression, obsession, and neuroticism) were found to be risk factors of suicide ideation in Chinese graduate students, and the interactions between them constructed a decision tree model. These findings should be helpful for school and mental health providers to detect graduate students with a high possibility of suicide ideation, which will aid in planning of early suicide intervention and prevention for at risk students

    Dimensional Dependence of Light Interaction with Nanowires

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    Semiconductor nanowires have been used in a variety of passive and active optoelectronic devices including waveguides, photodetectors, solar cells, LEDs, Lasers, sensors, and optical antennas. We examine GaAs/AlGaAs core-shell nanowires (CSNWs) grown on both GaAs and Si substrates by vapor-liquid-solid (VLS) method followed by Metal-Organic Chemical Vapor Deposition (MOCVD). These nanowires show extremely enhanced optical properties in terms of absorption, guiding, radiation of light, and even lasing. For the wavelength range of 700-1200nm these core-shells which only occupy 15% of the volume compared to thin films of the same height, reflect 2-4% of light for the CSNWs grown on Si, and 3-7% of light for those grown on GaAs substrate. The photoluminescence (PL) spectrum shows 923 times more light emitted from CSNWs grown on GaAs compared to bulk GaAs at room temperature, and optical pumped lasing with threshold of around 5 microwatt, followed by saturation near 12 microwatt. In addition, as-measured full-width half-max (FWHM) of ~13 ps time response has been demonstrated for CSNW using Electro-Optically Sampling (EOS) measurement. Analysis of the interaction of light with cylindrical and hexagonal structures with sub-wavelength diameters identifies both transverse and longitudinal plane modes which we generalize to volumetric resonant modes, importantly, without the need for vertical structures such as Bragg mirrors commonly used in vertical cavity surface emitting lasers (VCSEL's). We report on FDTD simulations with the aim of identifying the dependence of these modes on geometry (length, width), tapering, shape (cylindrical, hexagonal), core-shell versus core-only, and dielectric cores with semiconductor shells. This demonstrates how NWs form excellent optical cavities without the need for top and bottom mirrors. However, optically equivalent structures such as hexagonal and cylindrical wires can have very different optoelectronic properties meaning that light management alone does not sufficiently describe the observed enhancement in upward (absorption) and downward transitions (emission) of light in nanowires, rather, the electronic transition rates should be considered. Using Fermi's Golden Rule in interaction of light and matter, we discuss how the transition rates change due to electronic wave function and identify three factors, namely, oscillator strength, overlap functions, and the joint optical density of states(JDOS), explicitly contributing to the transition rates with strong dependence on dimensionality. We apply these results to the study of lasing in as-grown CSNW on Si & GaAs and discuss how these subwavelength structures can have enhanced optical gain, quantum efficiency and 175 times more optical output power compared to their bulk counterparts despite their large > 200nm geometries. These results and findings will further facilitate the design and optimization of sub-micron scale optoelectronic devices. In conclusion, we make a case for photonic integrated circuits that can take advantage of the confluence of the desirable optical and electronic properties of these nanostructures.Ph.D., Electrical Engineering -- Drexel University, 201

    Palaeoenvironment and Its Control on the Formation of Miocene Marine Source Rocks in the Qiongdongnan Basin, Northern South China Sea

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    The main factors of the developmental environment of marine source rocks in continental margin basins have their specificality. This realization, in return, has led to the recognition that the developmental environment and pattern of marine source rocks, especially for the source rocks in continental margin basins, are still controversial or poorly understood. Through the analysis of the trace elements and maceral data, the developmental environment of Miocene marine source rocks in the Qiongdongnan Basin is reconstructed, and the developmental patterns of the Miocene marine source rocks are established. This paper attempts to reveal the hydrocarbon potential of the Miocene marine source rocks in different environment and speculate the quality of source rocks in bathyal region of the continental slope without exploratory well. Our results highlight the palaeoenvironment and its control on the formation of Miocene marine source rocks in the Qiongdongnan Basin of the northern South China Sea and speculate the hydrocarbon potential of the source rocks in the bathyal region. This study provides a window for better understanding the main factors influencing the marine source rocks in the continental margin basins, including productivity, preservation conditions, and the input of terrestrial organic matter

    Practice of Comparative Effectiveness Research to Identify Treatment Characteristics of Similar Chinese Patent Medicine for Angina Pectoris

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    Objective. Individualized application of TCM is not easy and may lead to undesirable results, such as poor effect or even adverse reactions. This trial aims to compare two common Chinese patent medicines with similar effects. Background of the Research. Four hospitals carried out the test at the same time in Tianjin city of China. Participants. 144 patients were involved in this study; all patients must meet the diagnostic criteria. Interventions. Qishen Yiqi pills, compound danshen pills, and their placebos; an efficacy analysis was conducted after the first medication and after crossover medication. Primary Outcome Measures. The primary index of end point includes Seattle Angina Questionnaire score-7 and score of 7-point Likert Scale; the curative effect was compared with minimal clinically important differences value. Result. Two drugs have their respective advantages in treating SAP. In practical application, the two drugs shall be discriminated in use based on patients’ specific symptoms. Trial Registration. Chinese clinical trials register is ChiCTR-TTRCC-14004406 (registered 23 March 2014)

    Latilactobacillus sakei Furu2019 and stachyose as probiotics, prebiotics, and synbiotics alleviate constipation in mice

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    IntroductionSlow transit constipation (STC) is a common disorder in the digestive system. This study aimed to evaluate the effects of stachyose (ST) and Latilactobacillus sakei Furu 2019 (L. sakei) alone or combined on diphenoxylate-induced constipation and explore the underlying mechanisms using a mouse model.MethodsICR mice were randomly divided into five groups. The normal and constipation model groups were intragastrically administrated with PBS. The ST, L. sakei, and synbiotic groups were intragastrically administrated with ST (1.5 g/kg body weight), alive L. sakei (3 × 109 CFU/mouse), or ST + L. sakei (1.5 g/kg plus 3 × 109 CFU/mouse), respectively. After 21 days of intervention, all mice except the normal mice were intragastrically administrated with diphenoxylate (10 mg/kg body weight). Defecation indexes, constipation-related intestinal factors, serum neurotransmitters, hormone levels, short-chain fatty acids (SCFAs), and intestinal microbiota were measured.ResultsOur results showed that three interventions with ST, L. sakei, and synbiotic combination (ST + L. sakei) all alleviated constipation, and synbiotic intervention was superior to ST or L. sakei alone in some defecation indicators. The RT-PCR and immunohistochemical experiment showed that all three interventions relieved constipation by affecting aquaporins (AQP4 and AQP8), interstitial cells of Cajal (SCF and c-Kit), glial cell-derived neurotrophic factor (GDNF), and Nitric Oxide Synthase (NOS). The three interventions exhibited a different ability to increase the serum excitatory neurotransmitters and hormones (5-hydroxytryptamine, substance P, motilin), and reduce the serum inhibitory neurotransmitters (vasoactive intestinal peptide, endothelin). The result of 16S rDNA sequencing of feces showed that synbiotic intervention significantly increased the relative abundance of beneficial bacteria such as Akkermansia, and regulated the gut microbes of STC mice. In conclusion, oral administration of ST or L. sakei alone or combined are all effective to relieve constipation and the symbiotic use may have a promising preventive effect on STC

    Determination of astrophysical 12N(p,g)13O reaction rate from the 2H(12N, 13O)n reaction and its astrophysical implications

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    The evolution of massive stars with very low-metallicities depends critically on the amount of CNO nuclides which they produce. The 12^{12}N(pp,\,γ\gamma)13^{13}O reaction is an important branching point in the rap-processes, which are believed to be alternative paths to the slow 3α\alpha process for producing CNO seed nuclei and thus could change the fate of massive stars. In the present work, the angular distribution of the 2^2H(12^{12}N,\,13^{13}O)nn proton transfer reaction at Ec.m.E_{\mathrm{c.m.}} = 8.4 MeV has been measured for the first time. Based on the Johnson-Soper approach, the square of the asymptotic normalization coefficient (ANC) for the virtual decay of 13^{13}Og.s._\mathrm{g.s.} →\rightarrow 12^{12}N + pp was extracted to be 3.92 ±\pm 1.47 fm−1^{-1} from the measured angular distribution and utilized to compute the direct component in the 12^{12}N(pp,\,γ\gamma)13^{13}O reaction. The direct astrophysical S-factor at zero energy was then found to be 0.39 ±\pm 0.15 keV b. By considering the direct capture into the ground state of 13^{13}O, the resonant capture via the first excited state of 13^{13}O and their interference, we determined the total astrophysical S-factors and rates of the 12^{12}N(pp,\,γ\gamma)13^{13}O reaction. The new rate is two orders of magnitude slower than that from the REACLIB compilation. Our reaction network calculations with the present rate imply that 12^{12}N(p, γp,\,\gamma)13^{13}O will only compete successfully with the β+\beta^+ decay of 12^{12}N at higher (∼\simtwo orders of magnitude) densities than initially predicted.Comment: 8 figures, 2 tables, Submitted to Physical Review
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