1,490 research outputs found
Achieving Sustainable Growth in Developing Countries : Does Export Really Matter?
Peer reviewedPublisher PD
Socioeconomic Gradient in Childhood Obesity and Hypertension: A Multilevel Population-Based Study in a Chinese Community
published_or_final_versio
High Efficiency Organic Light Emitting Devices for Lighting
Incorporate internal scattering layers and microlens arrays in high efficiency OLED to achieve up to 70% EQE
On Geometric Ergodicity of Skewed - SVCHARME models
Markov Chain Monte Carlo is repeatedly used to analyze the properties of
intractable distributions in a convenient way. In this paper we derive
conditions for geometric ergodicity of a general class of nonparametric
stochastic volatility models with skewness driven by hidden Markov Chain with
switching
Modelling long-memory volatilities with leverage effect: A-LMSV versus FIEGARCH
A new stochastic volatility model, called A-LMSV, is proposed to cope simultaneously with leverage effect and long-memory in volatility. Its statistical properties are derived and compared with the properties of the FIEGARCH model. It is shown that the dependence of the autocorrelations of squares on the parameters measuring the asymmetry and the persistence is different in both models. The kurtosis and autocorrelations of squares do not depend on the asymmetry in the A-LMSV model while they increase with the asymmetry in the FIEGARCH model. Furthermore, the autocorrelations of squares increase with the persistence in the A-LMSV model and decrease in the FIEGARCH model. On the other hand, if the correlation between returns and future volatilities is negative, the autocorrelations of absolute returns increase with the magnitude of the asymmetry in the FIEGARCH model while they decrease in the A-LMSV model. Finally, the cross-correlations between squares and original observations are, in general, larger in absolute value in the FIEGARCH model than in the A-LMSV model. The results are illustrated by fitting both models to represent the dynamic evolution of volatilities of daily returns of the S&P500 and DAX indexes.Publicad
Lifestyle Intervention Using an Internet-Based Curriculum with Cell Phone Reminders for Obese Chinese Teens: A Randomized Controlled Study
Objectives
Obesity is an increasing public health problem affecting young people. The causes of obesity are multi-factorial among Chinese youth including lack of physical activity and poor eating habits. The use of an internet curriculum and cell phone reminders and texting may be an innovative means of increasing follow up and compliance with obese teens. The objectives of this study were to determine the feasibility of using an adapted internet curriculum and existing nutritional program along with cell phone follow up for obese Chinese teens.
Design and Methods
This was a randomized controlled study involving obese teens receiving care at a paediatric obesity clinic of a tertiary care hospital in Hong Kong. Forty-eight subjects aged 12 to 18 years were randomized into three groups. The control group received usual care visits with a physician in the obesity clinic every three months. The first intervention (IT) group received usual care visits every three months plus a 12-week internet-based curriculum with cell phone calls/texts reminders. The second intervention group received usual care visits every three months plus four nutritional counselling sessions.
Results
The use of the internet-based curriculum was shown to be feasible as evidenced by the high recruitment rate, internet log-in rate, compliance with completing the curriculum and responses to phone reminders. No significant differences in weight were found between IT, sLMP and control groups.
Conclusion
An internet-based curriculum with cell phone reminders as a supplement to usual care of obesity is feasible. Further study is required to determine whether an internet plus text intervention can be both an effective and a cost-effective adjunct to changing weight in obese youth.
Trial Registration
Chinese Clinical Trial Registry ChiCTR-TRC-12002624published_or_final_versio
Improving the design of industrial microwave processing systems through prediction of the dielectric properties of complex multi-layered materials
Rigorous design of industrial microwave processing systems requires in-depth knowledge of the dielectric properties of the materials to be processed. These values are not easy to measure, particularly when a material is multi-layered containing multiple phases, when one phase has a much higher loss than the other and the application is based on selective heating. This paper demonstrates the ability of the Clausius-Mossotti (CM) model to predict the dielectric constant of multi-layered materials. Furthermore, mixing rules and graphical extrapolation techniques were used to further evidence our conclusions and to estimate the loss factor. The material used for this study was vermiculite, a layered alumina-silicate mineral containing up to 10 % of an interlayer hydrated phase. It was measured at different bulk densities at two distinct microwave frequencies, namely 934 and 2143 MHz. The CM model, based on the ionic polarisability of the bulk material, gives only a prediction of the dielectric constant for experimental data with a deviation of less than 5 % at microwave frequencies. The complex refractive index model (CRIM), Landau, Lifshitz and Loyenga (LLL), Goldschmidt, Böttcher and Bruggeman-Hanai model equations are then shown to give a strong estimation of both dielectric constant and loss factor of the solid material compared to that of the measured powder with a deviation of less than 1 %. Results obtained from this work provide a basis for the design of further electromagnetic processing systems for multi-layered materials consisting of both high loss and low loss components
Flux lattice melting and depinning in the weakly frustrated 2D XY model
Monte Carlo simulations of the frustrated 2D XY model were carried out at
small commensurate values of the frustration . For a single
transition was observed at which phase coherence (finite helicity modulus) and
vortex lattice orientational order vanish together. For a new phase in
which phase coherence is absent but orientational order persists was observed.
Where comparison is possible, the results are in detailed agreement with the
behavior of the lattice Coulomb gas model of vortices. It is argued that the
helicity modulus of the frustrated 2D XY model vanishes for any finite
temperature in the limit of weak frustration .Comment: 4 pages, RevTeX, 3 figures in separate uuencoded file The manuscript
will appear in Phys. Rev.
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