201 research outputs found

    Investigating the Non-Linear Relationships in the Expectancy Theory: The Case of Crowdsourcing Marketplace

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    Crowdsourcing marketplace as a new platform for companies or individuals to source ideas or works from the public has become popular in the contemporary world. A key issue about the sustainability of this type of marketplace relies on the effort that problem solvers expend on the online tasks. However, the predictors of effort investment in the crowdsourcing context is rarely investigated. In this study, based on the expectancy theory which suggests the roles of reward valence, trust and self efficacy, we develop a research model to study the factors influencing effort. Further, the non-linear relationships between self efficacy and effort is proposed. Based on a field survey, we found that: (1) reward valence and trust positively influence effort; (2) when task complexity is high, there will be a convex relationship between self efficacy and effort; and (3) when task complexity is low, there will be a concave relationship between self efficacy and effort. Theoretical and practical implications are also discussed

    A Technology–Individual Contingency Perspective of Mobile Technostress: The Moderating Role of Personality

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    As one of the rapidly developing technologies, mobile technology brings employees not only the enhanced work effectiveness and efficiency but also some unexpected consequences such as the so called technostress which has been regarded as an increasingly serious issue in contemporary organizations. Despite prior studies have provided some interpretive and qualitative analysis on this issue, the empirical studies about how and when mobile technology features lead to technostress have been rarely developed. In this study, we proposed and empirically examined the impact of one key mobile technology feature namely presenteeism on technostress. More importantly, we further put forward that the relationship between technology characteristic and technostress was moderated by five personality factors namely extraversion, neuroticism, conscientiousness, agreeableness, and openness to experience by addressing the Five Factor Model (FFM) of personality. A survey on the employees with usage of mobile technologies in workplace was conducted to test the proposed research model and hypotheses. The key findings show that: (1) Presenteeism per se has no significant impact on technostress; (2) Three personality factors conscientiousness, agreeableness, and openness to experience are found to be significantly moderate the relationship between presenteeism and technostress while the other two does not. Contributions and implications of the study are also discussed

    Communication-Efficient Decentralized Multi-Agent Reinforcement Learning for Cooperative Adaptive Cruise Control

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    Connected and autonomous vehicles (CAVs) promise next-gen transportation systems with enhanced safety, energy efficiency, and sustainability. One typical control strategy for CAVs is the so-called cooperative adaptive cruise control (CACC) where vehicles drive in platoons and cooperate to achieve safe and efficient transportation. In this study, we formulate CACC as a multi-agent reinforcement learning (MARL) problem. Diverging from existing MARL methods that use centralized training and decentralized execution which require not only a centralized communication mechanism but also dense inter-agent communication, we propose a fully-decentralized MARL framework for enhanced efficiency and scalability. In addition, a quantization-based communication scheme is proposed to reduce the communication overhead without significantly degrading the control performance. This is achieved by employing randomized rounding numbers to quantize each piece of communicated information and only communicating non-zero components after quantization. Extensive experimentation in two distinct CACC settings reveals that the proposed MARL framework consistently achieves superior performance over several contemporary benchmarks in terms of both communication efficiency and control efficacy.Comment: 11 pages, 7 figure

    Homogeneous doping of substitutional nitrogen/carbon in TiO2 plates for visible light photocatalytic water oxidation

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    The authors thank National Natural Science Foundation of China (Grant Nos. 51825204, 51572266, 21633009, and 51629201), the Key Research Program of Frontier Sciences CAS (QYZDB‐SSW‐JSC039) for the financial support. G.L. is grateful for the award of the Newton Advanced Fellowship.Extending the light absorption range of wide‐bandgap photocatalysts into the visible light region is significant in terms of fully harvesting and converting solar light. The desirable band‐to‐band redshift of the absorption edge of semiconducting binary metal oxides such as prototypical photocatalyst TiO2 by doping is long targeted but remains a challenge, up to date. Here, by taking the advantage of abundant 1D diffusion channels with rhombus‐like cross‐sections along the c‐axis in the crystal structure of titanium oxalate hydrate to promote the entrance of nitrogen dopant species into the bulk and subsequent thermal topotactic transition in an atmosphere of gaseous ammonia, homogeneous doping of substitutional carbon/nitrogen for oxygen in the TiO2 decahedral plates with a dominant anatase phase is obtained for the first time. The resultant TiO2−x(CN)y with an unusual band‐to‐band visible light absorption spectrum can induce photocatalytic water oxidation to release oxygen under visible light irradiation. This study provides not only a promising visible light–responsive TiO2 photocatalyst, but also an important strategy for developing other solar‐driven photocatalysts.PostprintPeer reviewe

    UPLC-DAD/Q-TOF-MS Based Ingredients Identification and Vasorelaxant Effect of Ethanol Extract of Jasmine Flower

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    Chinese people commonly make jasmine tea for recreation and health care. Actually, its medicinal value needs more exploration. In this study, vasorelaxant effect of ethanol extract of jasmine flower (EEJ) on isolated rat thoracic aorta rings was investigated and [Ca2+] was determined in vascular smooth muscle cells by laser scanning confocal microscope (LSCM). The result of aorta rings showed that EEJ could cause concentration-dependent relaxation of endothelium-intact rings precontracted with phenylephrine or KCl which was attenuated after preincubation of the rings with L-NAME and three different K+ channel inhibitors; however, indomethacin and glibenclamide did not affect the vasodilatation of EEJ. In addition, EEJ could inhibit contraction induced by PE on endothelium-denuded rings in Ca2+-free medium as well as by accumulation of Ca2+ in Ca2+-free medium with high K+. LSCM also showed that EEJ could lower the elevated level of [Ca2+] induced by KCl. These indicate that the vasodilation of EEJ is in part related to causing the release of nitric oxide, activation of K+ channels, inhibition of influx of excalcium, and release of calcium from sarcoplasmic reticulum. A total of 20 main ingredients, were identified in EEJ by UPLC-DAD/Q-TOF-MS. The vasodilation activity should be attributed to the high content of flavonoid glycosides and iridoid glycosides found in EEJ

    PRL2 Controls Phagocyte Bactericidal Activity by Sensing and Regulating ROS

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    Although it is well-recognized that inflammation enhances leukocyte bactericidal activity, the underlying mechanisms are not clear. Here we report that PRL2 is sensitive to oxidative stress at inflamed sites. Reduced PRL2 in phagocytes causes increased respiratory burst activity and enhances phagocyte bactericidal activity. PRL2 (Phosphatase Regenerating Liver 2) is highly expressed in resting immune cells, but is markedly downregulated by inflammation. in vitro experiments showed that PRL2 was sensitive to hydrogen peroxide (H2O2), a common damage signal at inflamed sites. In response to infection, PRL2 knockout (KO) phagocytes were hyper activated, produced more reactive oxygen species (ROS) and exhibited enhanced bactericidal activity. Mice with PRL2 deficiency in the myeloid cell compartment were resistant to lethal listeria infection and cleared the bacteria more rapidly and effectively. Moreover, in vitro experiments demonstrated that PRL2 binds to GTPase Rac and regulates ROS production. Rac GTPases were more active in PRL2 (KO) phagocytes than in wild type cells after bacterium infection. Our findings indicate that PRL2 senses ROS at inflamed sites and regulates ROS production in phagocytes. This positive feedback mechanism promotes bactericidal activity of phagocytes and may play an important role in innate anti-bacterial immunity

    Video delivery networks : challenges, solutions and future directions

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    Internet video ecosystems are faced with the increasing requirements in versatile applications, ubiquitous consumption and freedom of creation and sharing, in which the user experience for high-quality services has become more and more important. Internet is also under tremendous pressure due to the exponential growth in video consumption. Video providers have been using content delivery networks (CDNs) to deliver high-quality video services. However, the new features in video generation and consumption require CDN to address the scalability, quality of service and flexibility challenges. As a result, we need to rethink future CDN for sustainable video delivery. To this end, we give an overview for the Internet video ecosystem evolution. We survey the existing video delivery solutions from the perspective of economic relationships, algorithms, mechanisms and architectures. At the end of the article, we propose a data-driven information plane for video delivery network as the future direction and discuss two case studies to demonstrate its necessity

    Characteristics of pathology and transcriptome profiling reveal features of immune response of acutely infected and asymptomatic infected of carp edema virus in Koi

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    Koi sleepy disease (KSD) is a high mortality and infection viral disease caused by carp edema virus (CEV), which was a serious threat to aquaculture of common carp and export trade of Koi worldwide. Asymptomatic infection is an important cause of the difficulty in preventing KSD and its worldwide spread, because asymptomatic infection can be activated under appropriate condition. However, the understanding of the molecular correlates of these infections is still unknown. The purpose of this study was to compare the pathology change, enzyme activity, immunoglobulin activity, host and viral gene expression differences in acutely infected and cohabiting asymptomatic Koi infected with CEV. Healthy Koi were used as a control. The gross pathology, histopathology and ultrastructural pathology showed the difference and characteristics damage to the tissues of Koi under different infection conditions. Periodic Acid-Schiff stain (PAS), enzyme activity and immunoglobulin activity revealed changes in the immune response of gill tissue between acutely infected, asymptomatic infected and healthy Koi. A total of 111 and 2484 upregulated genes and 257 and 4940 downregulated genes were founded in healthy Koi vs asymptomatic infected Koi and healthy Koi vs acutely infected Koi, respectively. Additionally, 878 upregulated genes and 1089 downregulated genes were identified in asymptomatic vs. acutely infected Koi. Immune gene categories and their corresponding genes in different comparison groups were revealed. A total of 3, 59 and 28 immune-related genes were identified in the group of healthy Koi vs asymptomatic infected Koi, healthy Koi vs acutely infected Koi and asymptomatic infected Koi vs acutely infected Koi, respectively. Nineteen immune-related genes have the same expression manner both in healthy Koi vs acutely infected Koi and asymptomatic Koi vs acutely infected Koi, while 9 immune-related genes were differentially expressed only in asymptomatic Koi vs acutely infected Koi, which may play a role in viral reactivation. In addition, 8 differentially expressed genes (DEGs) were validated by quantitative reverse transcription PCR (RT-qPCR), and the results were consistent with the RNA-Seq results. In conclusion, the data obtained in this study provide new evidence for further elucidating CEV-host interactions and the CEV infection mechanism and will facilitate the implementation of integrated strategies for controlling CEV infection and spread
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