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This work is a study of the thermal stability of (001)-cut Pb(Mg1/3Nb2/3)1-xTixO3 (x=0.30) single crystals before and after an electric (E)-field poling by means of dielectric permittivity, hysteresis loop, domain structure, polarization current, and x-ray diffraction. An R(RNT)-R(RNT)/T(TNT)-T(TNT)-C transition sequence was observed upon heating in the unpoled sample. R, RNT, T, TNT, and C are the rhombohedral, rhombohedral nanotwin, tetragonal, tetragonal nanotwin, and cubic phases, respectively. R/T indicates coexistence of the R and T phases. R(RNT) and T(TNT) indicate that the RNT and TNT structures mimic monoclinic phases in the R and T matrices, respectively. After a prior E-field poling, an R(RNT)-T(TNT)-C phase sequence takes place upon heating. The dielectric permittivity and current density evidenced an additional polarization at 355 K, which is associated with the vanishing of the dielectric dispersion, which reappears near 410 K and remains up to the Burns temperature TB=510 K. This study suggests that nanotwins (RNT and TNT) can play an important role in high-strain piezoelectric crystals while phase transition takes place. Under E=38 kV/cm, [001] T domains randomly appeared in the matrix, suggesting that the matrix consists of a glassy matrix and ferroelectric nanoclusters. [ABSTRACT FROM AUTHOR]

This paper tests the arguments put forth by Morgan (2004) and several others that the CRACK/Project Prevention programme, which offers substance-abusing women a monetary incentive to choose long-term or permanent birth control, is racist and unethical. Findings from a sample of 521 participants in the programme show that the majority of women chose a birth control method that was not permanent, and race did not play a statistically significant role in explaining the birth control choices among the women. Rather, the participant's age and the number of pregnancies she had experienced were more influential. The findings suggest that the prior criticisms of the programme for targeting minority and inherently vulnerable, addicted women for sterilisation are unsupported. Women in this study appeared to follow the larger trends among women of all races and socioeconomic backgrounds in choosing permanent birth control: they were older and had more children. [ABSTRACT FROM AUTHOR]

Studies have consistently found high levels of HIV infection among male-to-female (MTF) transgender people, particularly MTF sex workers. Due to lack of empirical data, HIV/AIDS risk among female-to-male (FTM) transgender people, however, is not well understood. This study analysed data from two needs assessment surveys to compare risk for HIV infection between 122 MTF and 62 FTM transgender people. Results show that there was a significant gender difference in HIV risk among the survey respondents. Compared to MTFs, FTMs were significantly less likely to have used protection the last time they had sex and significantly more likely to have engaged in recent high risk sexual activity. The gender difference existed even after controlling for demographic variables, AIDS knowledge, perceived AIDS knowledge, perceived effectiveness of condom usage, perceived susceptibility to AIDS and self-esteem. Findings from this study suggest that a thorough examination of HIV risk factors among FTMs is necessary. [ABSTRACT FROM AUTHOR]

The article presents a comparative study of three theoretical approaches including molecular simulation, the Peng-Robinson equation of state (PR EOS), and COSMO-SAC with the oxidation of cyclohexane.

The purpose of the present study is to develop a numerical model for the investigation of water waves propagating over a pair of impermeable submerged obstacles. The mathematic model is formulated by coupling solutions of the Navier–Stokes equations and transport equations for the surface elevation using the volume of fluid method. Based on a staggered computational mesh, an explicit numerical algorithm is employed with a predictor–corrector procedure of pressure and velocity field. The proposed model provides good agreement with other experimental results and validates its good performance. Regarding the spatial harmonic evolutions of various cases, it is noted that the present fluctuating mode of harmonic amplitudes exists upstream and at the gap between obstacles. The results show that the nonlinearity of propagating waves becomes stronger than the initial wave in such areas, and reveals much steeper wave profiles compared to the initial ones. The fluctuating harmonic amplitudes vary with the gap width and form two hydrodynamic cycles. The vortices play an important role in the wave reflection as they form a water column wall to reflect the incoming waves. The reflection ratio depends on the extent of vortex development near the upstream obstacle. The maximum wave reflection occurs in cases with dimensionless gap width S/L equal to 3/8 and 7/8 in this study. [ABSTRACT FROM AUTHOR]

This work is a study of phase transformation in (001)-cut Pb(Fe1/2Nb1/2)1-xTixO3 (x=48%) single crystals by means of dielectric permittivity, domain structure, and in situ x-ray diffraction. A first-order T(TNT)-C(TNT) phase transition was observed at the Curie temperature TC≅518 K upon zero-field heating. T, TNT, and C are tetragonal, tetragonal nanotwin, and cubic phases, respectively. T(TNT) and C(TNT) indicate that minor TNT domains reside in the T and C matrices. Nanotwins, which can cause broad diffraction peak, remain above TC≅518 K and give an average microscopic cubic symmetry in the polarizing microscopy. Colossal dielectric permittivity (>104) was observed above room temperature with strong frequency dispersion. This study suggests that nanotwins can play an important role in relaxor ferroelectric crystals while phase transition takes place. The Fe ion is a potential candidate as a B-site dopant for enhancing dielectric permittivity. [ABSTRACT FROM AUTHOR]

In recent years, the improvement of cloud computing and mobile computing techniques has led to the availability of a variety of mobile applications ('apps') in the app store. For instance, a garbage truck app that can provide the immediate location of a garbage truck, the location of collection points, and forecasted arrival times of garbage trucks would be useful for mobile users. Since the power consumption of apps on mobile devices if of concern to mobile users, an optimised power-saving mechanism for updating messages, which is based on location information, for a proposed garbage truck fleet management system (GTFMS) is proposed and implemented in this paper. The GTFMS is a three-component system that includes the on-board units on garbage trucks, a fleet management system, and a garbage truck app. In this study, an arrival time forecasting method is designed and implemented in the fleet management system, so that the garbage truck app can retrieve the forecasted arrival time via web services. A message updating event is then triggered that reports the location of garbage truck and the forecasted arrival time. In experiments conducted on case studies, the results showed that the mean accuracy of predicted arrival time by the proposed method is about 81.45 per cent. As for power consumption, the cost of traditional mobile apps is 2,880 times that of the mechanism proposed in this study. Consequently, the GTFMS can provide the precise forecasted arrival time of garbage trucks to mobile users, while consuming less power. [ABSTRACT FROM AUTHOR]

Cell refractive index is a key biophysical parameter, which has been extensively studied. It is correlated with other cell biophysical properties including mechanical, electrical and optical properties, and not only represents the intracellular mass and concentration of a cell, but also provides important insight for various biological models. Measurement techniques developed earlier only measure the effective refractive index of a cell or a cell suspension, providing only limited information on cell refractive index and hence hindering its in-depth analysis and correlation. Recently, the emergence of microfluidic, photonic and imaging technologies has enabled the manipulation of a single cell and the 3D refractive index of a single cell down to sub-micron resolution, providing powerful tools to study cells based on refractive index. In this review, we provide an overview of cell refractive index models and measurement techniques including microfluidic chip-based techniques for the last 50 years, present the applications and significance of cell refractive index in cell biology, hematology, and pathology, and discuss future research trends in the field, including 3D imaging methods, integration with microfluidics and potential applications in new and breakthrough research areas. [ABSTRACT FROM AUTHOR]