Sexual behaviour in the face of risk : preliminary results from first AIDS-related surveys

Preliminary results are presented from nationally representative surveys of the adult populations of five African countries, conducted in 1989 and 1990. General awareness of AIDS was high, as was knowledge of sexual transmission. In four of the five surveys, large proportions, from 25 to 64 per cent, of both men and women perceived themselves to have a high or moderate risk of HIV infection. High proportions also reported that they had modified their behaviour typically by more care in selecting partners or greater faithfulness. Greater use of condoms was mentioned rarely. The results, particularly on behavioural change, should not be interpreted literally. But the fact that so many report modification of behaviour at least suggests a willingness to contemplate the need for change. The prognosis would have been much worse, had these surveys indicated widespread denial of risk and unwillingness to consider changes in behaviour

Heat capacity of a thin membrane at very low temperature

We calculate the dependence of heat capacity of a free standing thin membrane on its thickness and temperature. A remarkable fact is that for a given temperature there exists a minimum in the dependence of the heat capacity on the thickness. The ratio of the heat capacity to its minimal value for a given temperature is a universal function of the ratio of the thickness to its value corresponding to the minimum. The minimal value of the heat capacitance for given temperature is proportional to the temperature squared. Our analysis can be used, in particular, for optimizing support membranes for microbolometers

Influence of water adsorbed on gold on van der Waals/Casimir forces

In this paper we investigate the influence of ultra thin water layer (1-1.5 nm) on the van der Waals/Casimir force between gold surfaces. Adsorbed water is inevitably present on gold surfaces at ambient conditions as jump-up-to contact during adhesion experiments demonstrate. Calculations based on the Lifshitz theory give very good agreement with the experiment in absence of any water layer for surface separations d>10 nm. However, a layer of thickness h<1.5 nm is allowed by the error margin in force measurements. At shorter separations, d<10 nm, the water layer can have a strong influence as calculations show for flat surfaces. Nonetheless, in reality the influence of surface roughness must also be considered, and it can overshadow any water layer influence at separations comparable to the total sphere-plate rms roughness w_{shp}+w.Comment: 8 pages, 5 figure, to be published in Phys. Rev.

Assessing the construct validity of the Quality-of-Life-Aged Care Consumers (QOL-ACC): an aged care-specific quality-of-life measure.

PURPOSE: To evaluate the construct (convergent and known group) validity of the Quality-of-Life-Aged Care Consumer (QOL-ACC), an older-person-specific quality-of-life measure designed for application in quality assessment and economic evaluation in aged care. METHODS: Convergent validity was assessed by examining relationships with other validated preference-based measures (EQ-5D-5L, ASCOT), quality of aged care experience (QCE-ACC) and life satisfaction (PWI) through an online survey. Known-group validity was assessed by testing the ability to discriminate varying levels of care needs, self-reported health and quality of life. RESULTS: Older people (aged ≥ 65 years) receiving community-aged care (N = 313) responded; 54.6% were female, 41.8% were living alone and 56.8% were receiving higher-level care. The QOL-ACC and its six dimensions were low to moderately and significantly correlated with the EQ-5D-5L (correlation co-efficient range, ρ = 0.39-0.56). The QOL-ACC demonstrated moderate and statistically significant correlations with ASCOT (ρ = 0.61), the QCE-ACC (ρ = 0.51) and the PWI (ρ = 0.70). Respondents with poorer self-reported health status, quality of life and/or higher-level care needs demonstrated lower QOL-ACC scores (P < 0.001), providing evidence of known-group validity. CONCLUSIONS: The study provides evidence of the construct validity of the QOL-ACC descriptive system. A preference-weighted value set is currently being developed for the QOL-ACC, which when finalised will be subjected to further validation assessments

High-sensitivity monitoring of micromechanical vibration using optical whispering gallery mode resonators

The inherent coupling of optical and mechanical modes in high finesse optical microresonators provide a natural, highly sensitive transduction mechanism for micromechanical vibrations. Using homodyne and polarization spectroscopy techniques, we achieve shot-noise limited displacement sensitivities of 10^(-19) m Hz^(-1/2). In an unprecedented manner, this enables the detection and study of a variety of mechanical modes, which are identified as radial breathing, flexural and torsional modes using 3-dimensional finite element modelling. Furthermore, a broadband equivalent displacement noise is measured and found to agree well with models for thermorefractive noise in silica dielectric cavities. Implications for ground-state cooling, displacement sensing and Kerr squeezing are discussed.Comment: 25 pages, 8 figure

On testing the violation of the Clausius inequality in nanoscale electric circuits

The Clausius inequality, one of the classical formulations of the second law, was recently found to be violated in the quantum regime. Here this result is formulated in the context of a mesoscopic or nanoscale linear RLC circuit interacting with a thermal bath. Previous experiments in this and related fields are analyzed and possibilities of experimental detection of the violation are pointed out. It is discussed that recent experiments reached the range of temperatures, where the effect should be visible, and that a part of the proposal was already confirmed.Comment: 5 pages revtex 4. No figure

Influence of random roughness on the Casimir force at small separations

The influence of random surface roughness of Au films on the Casimir force is explored with atomic force microscopy in the plate-sphere geometry. The experimental results are compared to theoretical predictions for separations ranging between 20 and 200 nm. The optical response and roughness of the Au films were measured and used as input in theoretical predictions. It is found that at separations below 100 nm, the roughness effect is manifested through a strong deviation from the normal scaling of the force with separation distance. Moreover, deviations from theoretical predictions based on perturbation theory can be larger than 100%.Comment: 18, 5 figure