On the Rayleigh -Brillouin scattering in air

GroundWinds lidar system is a high-spectral-resolution lidar system that can directly measure the Rayleigh-Brillouin scattering (RBS) spectra, from which the wind, temperature, and turbulence in the troposphere can be measured. Its transmitter is a double-frequency Nd-YAG laser at 532nm. Most of the data used in this research were taken on 31 July 2002. A widely used mathematic model---the S6 model---is fitted to the measured RBS spectra. The discrepancies between the measured temperature from the RayleighBrillouin spectra and from the radiosonde, combined with the discrepancies between the model and the measured RBS spectra, indicate that there is room for the S6 model to be improved. On the other hand, they also reveal that air turbulence information, which---along with the variance analysis---can be used in the turbulence measurements. The change in Rayleigh-Brillouin scattering spectra in fluids under external forces was theoretically investigated and can be used for acoustic wave detections, low-frequency plasma studies and other applications. In addition, Rayleigh backscatter coefficients in air, for the first time, were measured using the molecular photometric returns. The measured molecular backscatter coefficients are approximately twice as large as their theoretical counterparts. This could be related to the collective effects of air molecules, i.e., the scattering structure factor

MAJOR DEPRESSION AND INSULIN RESISTANCE AMONG NONDIABETIC U.S. ADULTS AGED 20-39 YEARS: THE ROLES OF GENDER AND RACE/ETHNICITY

The relationship between depression and insulin resistance has been evaluated in previous studies but with conflicting results. No study was found that investigates the role of race/ethnicity in the relationship between depression and insulin resistance. The purpose of this study was to: 1) determine the prevalence of major depression and insulin resistance among nondiabetic young adults aged 20-39 years in the United States, 2) examine the relationship between major depression and insulin resistance among nondiabetic young adults aged 20-39 years in the United States, and 3) determine whether this relationship varies by gender, race/ethnicity, or measure of depression. Analyses of cross-sectional data from the National Health and Nutrition Examination Survey (NHANES) 1999-2008 were performed. The study sample consisted of 1,054 (46.5%) men and 1,211 (53.5%) women who were nondiabetic and aged 20-39 years (N = 2,265). Major depression was measured by the Composite International Diagnostic Interview in NHANES 1999-2004 and by the Patient Health Questionnaire-9 in NHANES 2005-2008. Insulin resistance was measured by the homeostasis model assessment for insulin resistance. The prevalence of major depression and insulin resistance among nondiabetic U.S. adults aged 20-39 years in the study was 3.7% (n = 84; weighted % = 3.8) and 25.7% (n = 582; weighted % = 22.7) respectively. No significant association was found between major depression and insulin resistance in bivariate logistic regression analysis. However, a significant interaction effect between gender and major depression was observed. For men, major depression was negatively associated with insulin resistance after adjusting for age, race/ethnicity, systolic blood pressure, triglyceride level, high-sensitivity C-reactive protein, obesity, leisure time physical activity, smoking, and alcohol consumption. In contrast, no significant association between major depression and insulin resistance among women was found. There was no significant interaction between race/ethnicity and major depression. No significant variations in the relationship between major depression and insulin resistance by measure of depression were revealed. Study findings provide support for a significant positive relationship between insulin resistance and 1) systolic blood pressure, 2) triglyceride level, 3) and obesity as measured by body mass index or waist circumference among nondiabetic young adults aged 20-39 years

Body’s Death or Body’s Banishment?: 1 The Time Philosophy and As You Like It

In As You Like It, Court and Arden are two different settings where people have different experiences of life. Court is an epitome of the realistic world and the pastoral forest of Arden is a symbol of the lost paradise—Eden. In these two settings, time is a topic discussed frequently by the characters through the whole play. The characters hold different views of time and some of the views change with the transform of setting. Time in realistic world is linear time which devours man’ life little by little, while time in Arden is circular time which makes man feel eternity and tranquility. In addition, time experienced by the persons in love is changeable and elastic which is an intermediate state between the linear time and the circular time. This kind of multiple time philosophy reflects the characters’ various world views and outlooks on life.

A new efficient implicit scheme for discretising the stiff friction terms in the shallow water equations

© 2018 The Authors Discretisation of the friction terms to ensure numerical stability and accuracy remains to be challenging for the development of robust numerical schemes to solve the shallow water equations (SWEs), particularly for applications involving very shallow flows (e.g. overland flows and wet/dry fronts) over complex domain topography. The key challenge is to ensure relaxation of the flow towards an equilibrium state characterised by the balance between friction and gravity in a computationally efficient way. To overcome this numerical challenge, this paper proposes a novel approach for discretising the friction source terms in the SWEs in the context of an explicit finite volume method. The overall numerical scheme adopts the HLLC Riemann solver and surface reconstruction method (SRM) to explicitly discretise the flux and bed slope source terms. Whilst a fully implicit scheme is used to handle the friction source terms, solution to the implicit formulation is analytically derived to explicitly update the flow variables. Compared with the existing approaches, the proposed scheme effectively resolves the issue associated with stiff relaxation without necessity to use an iteration method and it supports efficient simulation using time steps controlled only by the Courant–Friedrichs–Levy (CFL) condition. The current friction term discretisation scheme is not coupled with flux and bed slope calculation and therefore may be readily implemented in any other explicit finite volume SWE models. After being successfully validated against two benchmark tests with analytical solutions, the resulting new SWE model is applied to reproduce a rainfall-flooding event in the Upper Lee catchment in the UK

Donor–Acceptor Fluorophores for Energy-Transfer-Mediated Photocatalysis

Triplet–triplet energy transfer (EnT) is a fundamental activation pathway in photocatalysis. In this work, we report the mechanistic origins of the triplet excited state of carbazole-cyanobenzene donor–acceptor (D–A) fluorophores in EnT-based photocatalytic reactions and demonstrate the key factors that control the accessibility of the 3LE (locally excited triplet state) and 3CT (charge-transfer triplet state) via a combined photochemical and transient absorption spectroscopic study. We found that the energy order between 1CT (charge transfer singlet state) and 3LE dictates the accessibility of 3LE/3CT for EnT, which can be effectively engineered by varying solvent polarity and D–A character to depopulate 3LE and facilitate EnT from the chemically more tunable 3CT state for photosensitization. Following the above design principle, a new D–A fluorophore with strong D–A character and weak redox potential is identified, which exhibits high efficiency for Ni(II)-catalyzed cross-coupling of carboxylic acids and aryl halides with a wide substrate scope and high selectivity. Our results not only provide key fundamental insight on the EnT mechanism of D–A fluorophores but also establish its wide utility in EnT-mediated photocatalytic reactions