A constitutive model for quasicrystal plasticity

High-pressure X-ray diffraction studies on gadolinium sesquioxide (Gd₂O₃) have been carried out up to a pressure of ～25 GPa in a diamond-anvil cell at room temperature. Gadolinium oxide, which has a cubic or bixbyite structure under ambient conditions, undergoes an irreversible structural phase at around 12 GPa. The high-pressure phase has been identified as a hexagonal La₂O₃-type structure. The bulk modulus and its pressure derivative of this phase have been calculated.     

Nanoscale inclusions in the phonon glass thermoelectric material Zn4Sb3

We have investigated the thermoelectric material Zn₄Sb₃ using transmission electron microscopy (TEM). Nanoscale inclusions with a diameter of about 10 nm were observed, constituting on the order of 1% by volume of the material. Studies using energy filtered imaging, electron diffraction, and high-angle annular dark-field STEM indicate that the inclusions consist of Zn. These inclusions are expected to scatter the medium and long-wavelength phonons effectively, thus contributing to phonon glass behavior which results in the exceptionally low thermal conductivity for this thermoelectric material.     

Electron irradiation damage in SnO

In a study of radiation effects in SnO we have found that electron-beam damage is observable from changes in a high-resolution electron microscopy image or electron diffraction pattern. The early stage of the damage is not accompanied by a change in composition or a loss of crystallinity. The dose required for this damage (about 600 C cm^?2) is approximately independent of electron energy (between 100 and 400 keV) and specimen temperature (between 100 and 300 K). The damage is believed to start with displacement of oxygen atoms from their lattice position through a radiolytic mechanism with an efficiency of approximately 10^?4.     

Linear-parabolic shift of initially sharp interface in AB diffusion couple above the ordering temperature

It is shown that initially sharp interface in AB diffusion couple, above the ordering temperature, can shift with anomalous kinetics, i.e. deviations from the parabolic growth kinetics are possible. The initial slopes of the shift versus time functions can be even unity for large diffusion asymmetry (the ratio of diffusion coefficients of the parent materials in orders of magnitude) and gradually decrease to 0.5 at larger distances (longer times). This is in accordance with earlier results obtained in phase separating systems. It is shown that from the results of simulations the crossover thickness, X*, between the linear and parabolic regimes can also be calculated, and the applicability of the linear–parabolic law is confirmed. Furthermore, it is illustrated that the crossover thickness depends exponentially on the diffusion asymmetry parameter, with the exponent close to the value obtained from analytical estimations.     

Art and life: Models for understanding music

Book Information Science, Truth, and Democracy. By Philip Kitcher. Oxford. New York. 2001. Pp. xiii + 219. US$27.50.     

Predictors of quality of life enjoyment and satisfaction in individuals living with HIV and AIDS in a resource-constrained setting in South Africa

The burden of HIV disease is concentrated in sub-Saharan Africa, particularly in South Africa (SA). Whilst there have been many studies conducted on the biomedical and socio-psychological aspects of HIV and AIDS, insufficient attention has been paid to the quality of life of those infected with the virus. The primary purpose of the study was to determine the predictors of quality of life enjoyment and satisfaction (Q-LES) among individuals infected with HIV. A battery of questionnaires, which included the Hospital Anxiety and Depression Scale (HADS) and the Quality of Life Enjoyment and Satisfaction Questionnaire (Q-LES-Q), were administered to 121 participants. Data was analysed using SPSS. Of the total sample (n = 121), 74% were females. The study found that a large proportion (49.5%) of the sample within the age group 25–49 years old experienced psychological distress. Those who were not on antiretroviral treatment (ART) were significantly affected (66%). Psychological distress was significantly prevalent among HIV positive individuals and also the strongest predictor of Q-LES among these individuals.     

The relationship between employees’ experience of performance management and work engagement within a South African organisation

The study investigated the relationship between employees’ experience of performance management and work engagement. Participants were a convenience sample of employed adults (N=202; females=59%, middle management?=?48%, White?=?54%, tenure more than 9 years?=?48%) in an organisation in the vehicle and asset-based finance industry. They completed the Performance Management Questionnaire (PMQ) and Utrecht Work Engagement Scale (UWES). Multiple regression analysis was used to determine the proportion of variance of work engagement that is explained by employees’ experience of performance management. Results revealed that only empowerment significantly predicted work engagement. These findings suggest that when employees experience performance management as empowering, they are also likely to have higher levels of work engagement.     

Psychological strengths and subjective well-being in South African white students

This study investigated the role of individual resources, notably self-efficacy, gratitude, and hope, in subjective well-being of white dormitory students at a historically white institution of higher learning. Using a convenience sample of white students (N?=?227), we tested the role of generalised self-efficacy, gratitude, and hope as indicators of a latent factor, labelled personal resources, in a structural equation model with subjective well-being as the latent output variable, measured by self-esteem and satisfaction with life. Path analyses indicated a reasonable fit between the data and our hypothesised theoretical model which proposed positive relations between levels of generalised self-efficacy, gratitude, dispositional hope, self-esteem and satisfaction with life. White students were psychologically doing well, considering above-midpoint levels obtained for levels of generalised self-efficacy, gratitude, dispositional hope, and satisfaction with life However, scores obtained for self-esteem and adult dispositional hope were below the mid-point and neutral respectively, indicating that White students do not agree that they experience high levels of these two psychological strengths. White female students experienced higher levels of hope, gratitude, and life satisfaction, while no significant gender differences were found for generalised self-efficacy and self-esteem. The results of this study highlight the potential for using psychological strengths to promote well-being in racially diverse students.     

Estimating One's Own and Others' Multiple Intelligence: A Cross-Cultural Study from Guinea Bissau and Portugal

This study examined the estimations of multiple intelligences for self, partner and parents. One hundred and fifty two students (males = 81, females = 68, and 3 have not indicated their sex; mean age = 24.02, SD = 3.08) from Guinea Bissau estimated their own, their partners', and their parents' IQ scores on each of Gardner's ten multiple intelligences: verbal (linguistic), logical (mathematical), spatial, musical, body-kinesthetic, interpersonal, intrapersonal, existential, spiritual and naturalistic. In contrast to previous results (A. Furnham, 2001) sex differences in self-estimates did not occur in this Guinean sample. Participants rated overall intelligence of their father higher than that of their mother. An existing data set on estimates of intelligence in a Portuguese sample was used for a cross-cultural comparison between Portuguese and Guinean participants. There were consistent and clear culture differences. Guinean gave higher self, partner and family ratings than Portuguese. Results are discussed in terms of the growing literature in the self-estimates of intelligence, as well as limitations of that approach.