447 research outputs found

    Investors’ Risk Preference Characteristics and Conditional Skewness

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    Perspective on behavioral finance, we take a new look at the characteristics of investors’ risk preference, building the D-GARCH-M model, DR-GARCH-M model, and GARCHC-M model to investigate their changes with states of gain and loss and values of return together with other time-varying characteristics of investors’ risk preference. Based on a full description of risk preference characteristic, we develop a GARCHCS-M model to study its effect on the return skewness. The top ten market value stock composite indexes from Global Stock Exchange in 2012 are adopted to make the empirical analysis. The results show that investors are risk aversion when they gain and risk seeking when they lose, which effectively explains the inconsistent risk-return relationship. Moreover, the degree of risk aversion rises with the increasing gain and that of risk seeking improves with the increasing losses. Meanwhile, we find that investors’ inherent risk preference in most countries displays risk seeking, and their current risk preference is influenced by last period’s risk preference and disturbances. At last, investors’ risk preferences affect the conditional skewness; specifically, their risk aversion makes return skewness reduce, while risk seeking makes the skewness increase

    Ultrafast magnetization enhancement and spin current injection in magnetic multilayers by exciting the nonmagnetic metal

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    A systematic investigation of spin injection behavior in Au/FM (FM = Fe and Ni) multilayers is performed using the superdiffusive spin transport theory. By exciting the nonmagnetic layer, the laser-induced hot electrons may transfer spin angular momentum into the adjacent ferromagnetic (FM) metals resulting in ultrafast demagnetization or enhancement. We find that these experimental phenomena sensitively depend on the particular interface reflectivity of hot electrons and may reconcile the different observations in experiment. Stimulated by the ultrafast spin currents carried by the hot electrons, we propose the multilayer structures to generate highly spin polarized currents for development of future ultrafast spintronics devices. The spin polarization of the electric currents carried by the hot electrons can be significantly enhanced by the joint effects of bulk and interfacial spin filtering. Meanwhile the intensity of the generated spin current can be optimized by varying the number of repeated stacking units and the thickness of each metallic layer.Comment: 11 pages, 6 figure

    Sequence analysis reveals mosaic genome of Aichi virus

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    Aichi virus is a positive-sense and single-stranded RNA virus, which demonstrated to be related to diarrhea of Children. In the present study, phylogenetic and recombination analysis based on the Aichi virus complete genomes available in GenBank reveal a mosaic genome sequence [GenBank: FJ890523], of which the nt 261-852 region (the nt position was based on the aligned sequence file) shows close relationship with AB010145/Japan with 97.9% sequence identity, while the other genomic regions show close relationship with AY747174/German with 90.1% sequence identity. Our results will provide valuable hints for future research on Aichi virus diversity

    Guanylate-binding protein 1 participates in cellular antiviral response to dengue virus

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    BACKGROUND: Dengue virus (DENV), the causative agent of human Dengue hemorrhagic fever, is a mosquito-borne virus found in tropical and sub-tropical regions around the world. Vaccines against DENV are currently unavailable. Guanylate-binding protein 1 (GBP1) is one of the Interferon (IFN) stimulated genes (ISGs) and has been shown important for host immune defense against various pathogens. However, the role of GBP1 during DENV infection remains unclarified. In this study, we evaluated the relevance of GBP1 to DENV infection in in vitro model. FINDINGS: Quantitative RT-PCR (qRT-PCR) and Western blot showed that the expression of mouse Gbp1 was dramatically upregulated in DENV-infected RAW264.7 cells. The intracellular DENV loads were significantly higher in Gbp1 silenced cells compared with controls. The expression levels of selective anti-viral cytokines were decreased in Gbp1 siRNA treated cells, while the transcription factor activity of NF-κB was impaired upon GBP1 silencing during infection. CONCLUSIONS: Our data suggested that GBP1 plays an antiviral role during DENV infection

    Dependence on the structure and surface polarity of ZnS photocatalytic activities of water splitting: first-principles calculations

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    It has been reported that phase structure and surface polarity largely affect the photocatalytic efficiency of semiconductor nanostructures. To understand the chemical activity of ZnS at the electronic level, we investigate electron structures and carrier transportation ability for bulk intrinsic zinc blende (ZB) and wurtzite (WZ) ZnS, as well as the reaction pathway of hydrogen generation from water splitting on Zn- and S-terminated polar surfaces. The electron structure calculations prove that the WZ phase possesses a higher reducing ability than the ZB phase. The conductivity of the bulk ZB phase surpasses that of the WZ phase at or above room temperature. As the temperature increases, the asymptotic conductivity ratio of WZ/ZB is close to the Golden Ratio, 0.62. Reaction kinetics studies indicate that Zn-terminated polar surfaces are more chemically active than S-terminated polar surfaces in the reaction of hydrogen generation from water splitting. The calculation results suggest that the first H splitting from water on Zn-terminated polar surfaces can occur with ground state electronic structures, while photo-assistance is necessary for the first H splitting on the S-terminated surfaces. Electronic triplet states calculations further show that Zn-terminated surfaces are more photosensitive than S-terminated surfaces

    NiO hollow microspheres interconnected by carbon nanotubes as an anode for lithium ion batteries

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    In this work, NiO hollow microspheres interconnected by multi-walled carbon nanotubes (MWCNTs) were prepared, characterized, and evaluated in terms of lithium ion storage properties. Characterization results showed that the NiO hollow microspheres were formed by self assembly of NiO nanoparticles promoted by MWCNTs, which connected the NiO microspheres to form a long-range network. Electrochemical measurement results showed a charge capacity as high as 597.2 mAh g when cycling at the rate 2 C and maintained 85.3% capacity of 0.1 C. After cycling for 100 times at 1 C, it maintained a capacity of 692.3 mAh g with retention 89.3% of the initial capacity. The observed excellent electrochemical performance is attributed to the presence of MWCNTs interconnecting the NiO microspheres of the composite material, of which electronic conductivity was improved, and the mesoporous hollow structure effectively alleviated the volume changes to maintain the structural stability during cycling

    CAVEAT ON THE ERROR ANALYSIS FOR STEREOLOGICAL ESTIMATES

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    It is frequently asked that how big a sample size, or how much measurement, is needed to achieve an accuratestereological estimate. The observed total error of a stereological estimate arises from individual difference (i.e. i ter-animal / organ difference or biological variation) and intra-individual variation (or the stereological error). Statistical methods for error analysis familiar to most biological researchers are based on independent random sampling, however systematic random sampling, which is usually more efficient, is almost always performed in practice. A number of methods for error analysis were utilized in a number of model and actual studies in this paper to demonstrate from a practical point of view the pros and cons of different error analytical methods. Assumption of independence for a systematic sampling will result in overestimation of the stereological error as shown by the studies. A simple and practical approach for error analysis as recommended in this paper is to divide the systematic sample from an organ into two systematic sub-samples, regard them as two independent sub-samples and then compare the difference between the two sub-sample means

    The Effects of Prior Outcomes on Risky Choice: Evidence from the Stock Market

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    How do prior outcomes affect the risk choice? Research on this can help people to understand investors’ dynamic decisions in financial market. This paper puts forward a new value function. By analyzing the new value function, we find that the prior gains and losses have an impact on the form of value function and the current investors’ risk attitude. Then the paper takes the behavior of the whole stock market as the research object, adopts aggregative index number of 14 representative stocks around the world as samples, and establishes a TVRA-GARCH-M model to investigate the influences of prior gains and losses on the current risk attitude. The empirical study indicates that, at the whole market level, prior gains increase people’s current willingness to take risk assert; that is to say, the house money effect exists in the market, while people are more risk aversion following prior losses

    NF-κB Signaling in the Brain of Autistic Subjects

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    Autism is a neurodevelopmental disorder characterized by problems in communication, social skills, and repetitive behavior. Recent studies suggest that apoptotic and inflammatory mechanisms may contribute to the pathogenesis of this disorder. Nuclear factor-κB (NF-κB) is an important gene transcriptional factor involved in the mediation of inflammation and apoptosis. This study examined the activities of the NF-κB signaling pathway in the brain of autistic subjects and their age-matched controls. The NF-κB activation is also determined in the brain of BTBR mice, which is a promising animal model for study of pathogenic mechanisms responsible for autism. Our results showed that the level of IKKα kinase, which phosphorylates the inhibitory subunit IκBα, is significantly increased in the cerebellum of autistic subjects. However, the expression and phosphorylation of IκBα are not altered. In addition, our results demonstrated that the expression of NF-κB (p65), and the phosphorylation/activation of NF-κB (p65) at Ser536 are not significantly changed in the cerebellum and cortex of both autistic subjects and BTBR mice. Our findings suggest that the NF-κB signaling pathway is not disregulated in the brain of autistic subjects and thus may not be significantly involved in the processes of abnormal inflammatory responses suggested in autistic brain
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