Translational Heating of D2 Molecules Thermally Desorbed from Si(100) and Ge(100) Surfaces

The translational energies of D2 molecules thermally desorbed from the Si(100) and Ge(100) surfacesunder a heating rate of 6 K=s have been measured. In contrast to the previous laser desorption study,results show a considerable translational heating; the observed translational temperature is about 3 timeshigher than the desorption temperature for both surfaces. This fact indicates that energy barriers foradsorption are present even in the desorption pathway. Detailed balance is applicable to the adsorption anddesorption dynamics of hydrogen on the Si(100) surface

Translational Heating of D2 Molecules Thermally Desorbed from Si(100) and Ge(100) Surfaces

The translational energies of D2 molecules thermally desorbed from the Si(100) and Ge(100) surfaces under a heating rate of 6 K=s have been measured. In contrast to the previous laser desorption study, results show a considerable translational heating; the observed translational temperature is about 3 times higher than the desorption temperature for both surfaces. This fact indicates that energy barriers for adsorption are present even in the desorption pathway. Detailed balance is applicable to the adsorption and desorption dynamics of hydrogen on the Si(100) surface

Observation of coherent backscattering of light by cold atoms

Coherent backscattering (CBS) of light waves by a random medium is a signature of interference effects in multiple scattering. This effect has been studied in many systems ranging from white paint to biological tissues. Recently, we have observed CBS from a sample of laser-cooled atoms, a scattering medium with interesting new properties. In this paper we discuss various effects, which have to be taken into account for a quantitative study of coherent backscattering of light by cold atoms.Comment: 25 pages LaTex2e, 17 figures, submitted to J. Opt. B: Quant. Semicl. Op

Nutritional variation and cardiovascular risk factors in Tanzania — rural-urban difference

Objective. To assess the relationship between dietary factors and cardiovascular (CVD) risk factors in middle-aged men and women, in urban, rural and pastoral settings in Tanzania.Design. Cross-sectional epidemiological study designed according to the protocol of the World Health Organisation (WHO) Cardiovascular Diseases and Alimentary Comparison (CARDIAC) study.Setting. Three centres in Tanzania, namely Dar es Salaam (urban), Handeni (rural) and Monduli (pastoral population).                                                                                                                                                     Subjects. The subjects, aged 47 - 57 years, were recruited randomly from administrative lists available from each centre.Outcome measures. Blood pressure (BP) was measured using a centrally calibrated automatic BP machine (Khi machine). Dietary history of the participants was obtained using a standard questionnaire designed on the basis of a seven-day recall system. Height, weight, serum total cholesterol (TC) and high-density lipoprotein cholesterol (HDLC), haemoglobin A1c , sodium, potassium and magnesium were measured.Results. The prevalence of hypertension (BP ≥ 140/90 mmHg or antihypertensive drug use), obesity (body mass index (BMI)≥ 30 kg/m2) and hypercholesterolaemia (TC > 5.2 mmol/l) were lowest in the rural area. Consumption of green vegetables, milk, coconut milk, meat, and fish varied significantly between the three areas. Important determinants for BP among men were BMI (p < 0.001), and salt intake (p < 0.05). Among women, TC (p < 0.05), age (p < 0.05), BMI (p < 0.001) and coconut milk consumption (p < 0.001)were important BP determinants. Salt intake was positively associated with systolic BP (SBP) and diastolic BP (DBP) in men but not among women (both SBP and DBP p < 0.05 respectively). Dietary determinants of serum TC were meat, fish and green vegetable consumption.Conclusion. Differences in dietary habits contributed significantly to the urban-rural-pastoral variations in CVD risk pattern in Tanzania