246 research outputs found

    The Research of Periodic Solutions of Time-Varying Differential Models

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    We have studied the periodicity of solutions of some nonlinear time-varying differential models by using the theory of reflecting functions. We have established a new relationship between the linear differential system and the Riccati equations and applied the obtained results to discuss the behavior of periodic solutions of the Riccati equations

    Can Social Disconnectedness Inhibit Online Trade? Examining the Effects of Digital Distance on Peer-to-peer Lending

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    The extant literature has shown that offline group proximity manifests in online peer-to-peer lending platforms, inhibiting online transactions in those markets. The findings of this research suggest that digital distance, as measured by the rate of Facebook friendship between country pairs, can also influence lending actions in bi-country lending. Building on a dataset from Kiva.org, we show that digital distance significantly and negatively affects bi-country lending actions, on top of other distance-related barriers discussed in the literature. The results also shed light on the role of government policies regarding local IT infrastructure and Internet freedom, revealing that greater levels of IT infrastructure and Internet freedom can compensate for the negative effect of digital distance on prosocial lending

    A Longitudinal Study of Recurrent Experience of Earthquake and Mental Health Problems Among Chinese Adolescents

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    Background: The effects of recurrent exposure to disasters on adolescents’ mental health have rarely been studied. We examined the effects of two earthquake experiences 5 years apart in a longitudinal cohort of Chinese adolescents.Methods: A total of 858 adolescents were assessed in September, 2011 (3.5 years after the Wenchuan earthquake, 1.5 years before Ya’an earthquake, T1) and April, 2013 (1 week after the Ya’an earthquake, T2). Participants’ Wenchuan earthquake experiences and symptoms of post-traumatic stress disorder (PTSD) and depression were assessed at T1, and their Ya’an earthquake experiences, Acute Stress Disorder (ASD), PTSD, and depression were assessed at T2.Results: Structural equation models showed a positive relationship between Ya’an earthquake experiences and symptoms of ASD, PTSD, and depression at T2. T1 PTSD symptoms significantly increased T2 ASD, PTSD, and depression symptoms, and also mediated the relationships between Wenchuan earthquake experiences and T2 ASD, PTSD, and depression symptoms. T1 Depression symptoms also significantly increased T2 ASD, PTSD, and depression symptoms, but only mediated the association between Wenchuan earthquake experiences and T2 depression symptoms. In addition, Wenchuan earthquake experiences moderated the effects of Ya’an earthquake experiences on ASD symptoms and PTSD symptoms but not depression.Conclusion: Repeated to exposure to disasters have adverse additive effects on adolescents’ mental health. Adolescents who experience one disaster may be sensitive to the negative impact of subsequent ones

    Effect of in vitro gastrointestinal digestion on the chemical composition and antioxidant properties of Ginkgo biloba leaves decoction and commercial capsules

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    In this study Ginkgo biloba leaves (GBL) decoction and commercial capsules were digested using an in vitro model. Thirty-six active compounds were identified and quantified by HPLC-ESI-MS analysis based on the MS/MS patterns (precursor ions and product ions) and retention times, in comparison with reference standards. Most compounds in GBL showed a significant decrease during intestinal digestion, with an exception of vanillic acid and biflavonoids. Bioaccessibility values of chemical compositions varied between decoction and capsules samples. Also, significant reductions of total flavonoids and total phenolic content was observed after in vitro digestion. Both, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2â€Č-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) scavenging capacity decreased after gastric digestion, but increased during intestinal digestion. Nevertheless, different behaviour was observed in reducing antioxidant power (FRAP) assay. Compared to the pH of digestion, the influence of digestive enzymes on the chemical composition and antioxidant activity of GBL was relatively minor. Overall, these results may help provide a valid foundation for further investigations on bioactive compounds and the pharmacodynamics of GBL

    Research on model fitting and strength characteristics of critical state for expansive soil

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    According to Mengzi expansive soil, consolidated drained tests and undrained tests are carried on under saturated and remoulded conditions. The stress-strain characteristics of saturated soil are researched systematically under different confining pressure, initial dry density, initial water content, shearing rate and drainage condition. The inherent unity of diversity of shearing strength for the same samples measured by different experimental methods is indicated according to the normalization of critical state test results. And the failure lines in p ‘- q - Îœ space of remoulded saturated expansive soil under consolidated drained and undrained conditions are attained. The hyperbolic curve model can fit well the weak hardening stress-strain curves and the exponential curve model can fit the weak softening stress-strain curves. The test results can provide technical parameters and theoretical help for shearing strength variation of slope during rainfall and strength state of soil structure in normal water level

    Ultra-low threshold continuous-wave quantum dot mini-BIC lasers

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    Highly compact lasers with ultra-low threshold and single-mode continuous wave (CW) operation have been a long sought-after component for photonic integrated circuits (PICs). Photonic bound states in the continuum (BICs), due to their excellent ability of trapping light and enhancing light-matter interaction, have been investigated in lasing configurations combining various BIC cavities and optical gain materials. However, the realization of BIC laser with a highly compact size and an ultra-low CW threshold has remained elusive. We demonstrate room temperature CW BIC lasers in the 1310 nm O-band wavelength range, by fabricating a miniaturized BIC cavity in an InAs/GaAs epitaxial quantum dot (QD) gain membrane. By enabling effective trapping of both light and carriers in all three dimensions, ultra-low threshold of 12 {\mu}W (0.052 kW/cm^2) is achieved. Single-mode lasing is also realized in cavities as small as only 5*5 unit-cells (~2.5*2.5 {\mu}m^2 cavity size) with a mode volume of 1.16({\lambda}/n)^3. With its advantages in terms of a small footprint, ultralow power consumption, robustness of fabrication and adaptability for integration, the mini-BIC lasers offer a perspective light source for future PICs aimed at high-capacity optical communications, sensing and quantum information

    A Review of Asian Financial Crisis in the End of 1990s

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    In Asian Financial Crisis during the end of 1990s, millions of people lost their money in one day, international investors were reluctant to lend to developing countries, leading to economic slowdowns in developing countries in many parts of the world. This paper will talk about how the crisis become, speculators how to speculated the financial market, a case in HK how to defeat speculators attack, and IMF provided support package for rescuing attacked countries.  We hope our paper can give some ideas to people and show the importance on balancing the domestic economy to avoid the crisis happen again

    Hyperuricemia and severity of coronary artery disease: An observational study in adults 35 years of age and younger with acute coronary syndrome

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    Background: Coronary artery disease (CAD) in adults ≀ 35 years of age is rare, but the incidence is on the rise and the risk factors for this age group are largely uncertain. Previous studies have shown that hyperuricemia (HUA) is an independent risk factor for CAD in the general population, whereas the role in adults ≀ 35 years of age with acute coronary syndrome (ACS) is unclear. Methods: Patients, 18–35 years of age, diagnosed with ACS for the first time at the documented institu- tion between January 2005 and December 2015, were enrolled in the current study. The severity of CAD was assessed by the Gensini score. Patients were divided into two groups according to the definition of HUA. The relationship between HUA and CAD severity was assessed based on multi-variate analysis.  Results: Seven hundred seventy-one participants fulfilling the criteria were included in this study (mean age, 31.6 years; 94.4% male). HUA, which was defined as a serum uric acid level ≄ 7.0 mg/dL (420ÎŒmol/L) in males and ≄ 6.0 mg/dL (357 ÎŒmol/L) in females, accounted for 37% of the participants. Multivariate analysis identified that HUA is an independent risk factor of CAD severity, as assessed by the Gensini score, in very young adults with ACS (OR 8.28; 95% CI 1.96–14.59; p = 0.01), and the effect of HUA on CAD severity was second only to diabetes mellitus. Conclusions: Hyperuricemia was shown to be an independent risk factor for CAD severity in young adults with ACS (18–35 years of age)
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