8,720 research outputs found

    Moderating Effects of Information-Oriented versus Escapism-Oriented Motivations on the Relationship Between Psychological Well-Being and Problematic Use of Video Game Live-Streaming services

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    Background and aims: Video game live-streaming platforms are widely used by gamers. However, the excessive use of such services has rarely been examined. Although psychosocial well-being and motivations for use have been demonstrated to play major roles in online addiction, understanding the moderating mechanism of these two factors is warranted. Video game live-streaming platforms are an ideal context for studying the moderating role of both informational and escapism motivations, because viewers on such platforms can learn gaming strategies or escape from the reality. Methods: This study collected survey data from 508 users of the highly popular game-streaming service Twitch. The sample was divided into two groups based on the respondents’ use motivations. Regression models with interaction terms were fitted, followed by a simple slope test, to verify the hypotheses. Results: For the escapism-oriented group, a moderating effect of escapism on the relationship between loneliness and negative outcomes was found; the relationship was positive for low and moderate levels of escapism, but it was non-significant for individuals with high levels of escapism. For the information-oriented group, information seeking was observed to exert a moderating effect on the relationship between stress and negative outcomes; the relationship was negative for low and moderate levels of information seeking, but it was non-significant for individuals demonstrating high levels of information seeking. Discussion and conclusions: The findings promote understanding regarding how individuals using similar Internet-related coping strategies to deal with problems differ in their propensity for experiencing negative consequences when motivation levels and online environments are considered

    Fabrication, characterization, and kinetic study of vertical single-crystalline CuO nanowires on Si substrates

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    We report here on the first study of the growth kinetics of high-yield, vertical CuO nanowires on silicon substrates produced by the process of thermal oxidation. The length of the CuO nanowires could be tuned from several to tens of micrometers by adjusting the oxidation temperature and time. The grown CuO nanowires were determined to be single-crystalline with different axial crystallographic orientations. After a series of scanning electron microscopy examinations, the average length of CuO nanowires produced at each temperature was found to follow a parabolic relationship with the oxidation time. The parabolic growth rate at different oxidation temperatures was measured. The activation energy for the growth of CuO nanowires calculated from an Arrhenius plot was found to be about 174.2 kJ/mole. In addition, the current-voltage characterization indicated that the sample with high-density CuO nanowires exhibited ohmic behavior, and its resistance was found to significantly decrease with increasing environmental temperature. The result can be attributed to an increase in the number of carriers at higher temperatures

    Effect of Auction Design on Bidder Entry: Evidence from An Online Labor Market

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    We propose that auction duration and auction description are two important auction design parameters that could serve as screening mechanisms for quality in online auctions. Using data from an online labor matching platform that connects buyers with IT service vendors, we examine the effects of auction duration and auction descriptions on auction outcomes (i.e., number of bids, bidder quality, bidding price) and project outcomes (i.e., project being contracted and being completed). Our empirical analyses show that, in buyer-determined reverse auctions of online labor matching, auctions with a longer duration and a longer description attract more bids, but they also attract more low quality bidders with less experience and lower completion rate, and hence result in a lower probability of successful contracting and completion of software service projects. Our research provides empirical evidence highlighting the strategic roles of auction design parameters like auction duration and descriptions as a potential screening mechanism for online labor matching platforms

    Accurate and efficient hydrodynamic analysis of structures with sharp edges by the Extended Finite Element Method (XFEM): 2D studies

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    Achieving accurate numerical results of hydrodynamic loads based on the potential-flow theory is very challenging for structures with sharp edges, due to the singular behavior of the local-flow velocities. In this paper, we introduce the Extended Finite Element Method (XFEM) to solve fluid-structure interaction problems involving sharp edges on structures. Four different FEM solvers, including conventional linear and quadratic FEMs as well as their corresponding XFEM versions with local enrichment by singular basis functions at sharp edges, are implemented and compared. To demonstrate the accuracy and efficiency of the XFEMs, a thin flat plate in an infinite fluid domain and a forced heaving rectangle at the free surface, both in two dimensions, will be studied. For the flat plate, the mesh convergence studies are carried out for both the velocity potential in the fluid domain and the added mass, and the XFEMs show apparent advantages thanks to their local enhancement at the sharp edges. Three different enrichment strategies are also compared, and suggestions will be made for the practical implementation of the XFEM. For the forced heaving rectangle, the linear and 2nd order mean wave loads are studied. Our results confirm the previous conclusion in the literature that it is not difficult for a conventional numerical model to obtain convergent results for added mass and damping coefficients. However, when the 2nd order mean wave loads requiring the computation of velocity components are calculated via direct pressure integration, it takes a tremendously large number of elements for the conventional FEMs to get convergent results. On the contrary, the numerical results of XFEMs converge rapidly even with very coarse meshes, especially for the quadratic XFEM

    Studying newborn neutron stars by the transient emission after stellar collapses and compact binary mergers

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    The formation of neutron stars (NSs), both from collapses of massive stars and mergers of compact objects, can be usually indicated by bright transients emitted from explosively-ejected material. In particular, if the newborn NSs can rotate at a millisecond period and have a sufficiently high magnetic field, then the spin-down of the NSs would provide a remarkable amount of energy to the emitting material. As a result, super-luminous supernovae could be produced in the massive stellar collapse cases, while some unusual fast evolving and luminous optical transients could arise from the cases of NS mergers and accretion-induced collapses of white dwarfs. In all cases, if the dipolar magnetic fields of the newborn NSs can be amplified to be as high as 101510^{15} G, a relativistic jet could be launched and then a gamma-ray burst can be produced as the jet successfully breaks out from the surrounding nearly-isotropic ejected material.Comment: 10 pages, 9 pictures, to appear in the AIP Proceedings of the Xiamen-CUSTIPEN Workshop on the EOS of Dense Neutron-Rich Matter in the Era of Gravitational Wave Astronomy, Jan. 3-7, Xiamen, Chin

    Incompressible SPH simulation of solitary wave interaction with movable seawalls

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    In this paper, we applied an incompressible Smoothed Particle Hydrodynamics (SPH) method to investigate the impact of solitary waves on seawalls, especially movable seawalls. The SPH method is a mesh-free numerical approach particularly suitable for dealing with large free surface deformations and complex fluid-structure interactions. The incompressible SPH (ISPH) method solves the pressure field using the pressure Poisson equation (PPE), rather than relying on the equation of state. It has the advantage of producing more stable and accurate pressure fields and impact forces on structures. We first applied the model to simulate the solitary wave propagation and runup against a fixed vertical wall. The computations compared well with previous experimental and numerical results. Then, the solitary wave impact on a movable structure was investigated by replacing the fixed wall with a spring-controlled seawall subject to different spring stiffness and mass settings. Particular attention was paid to the prediction of the seawall movement, wave runup height and hydrodynamic loading. The incident wave height was found to be the dominant factor for the movable seawall movement during and immediately after the wave crest arrival at the seawall. Other factors, such as the seawall mass and spring stiffness, become important to the seawall's responses only after the maximum impact.Dr. D. Liang acknowledges the financial support of the MPM-DREDGE Project funded by the European Commission’s Seventh Framework Programme (PIAP-GA-2012-324522) and the Royal Academy of Engineering (NRCP/1415/97 and ISS1516\8\34). Dr. W. Jian acknowledges the Churchill Jafar Studentship for her Ph.D study at the University of Cambridge. Dr. S. Shao acknowledges the support of the Major State Basic Research Development Program (973) of China (No. 2013CB036402)

    From imitation to innovation: A study of China's drug R&D and relevant national policies

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    Research & Development (R&D) plays an increasingly important role in China's pharmaceutical industry. To gain a competitive edge in the global pharmaceutical market, the current national strategy of China forcefully pushes for independent drug innovations. This article investigates the historical, legal, and institutional contexts in which China's drug R&D has evolved. Based on an analysis of the drug R&D evolution and national policies in China, it predicts the future trend of China's policies relevant to drug innovations. This paper helps to understand the impact of national policies on drug R&D in China, which can be used to inform decision-making on investments in China's pharmaceutical market or conducting technology trade and international cooperation with Chinese partners
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