Human energy expenditure in lowland rice cultivation in Malaysia.

A study was undertaken to evaluate the human energy consumption of various field operations involved in lowland rice cultivation in Malaysia. Based on recorded average heart rates, fertilizing was found to be the most strenuous operation, with an average heart rate of 138 beats min(-1). There were no significant differences in the average heart rates of the subjects among the individual tasks within the first plowing, second plowing, and harvesting operations, with the average heart rates for these three tasks being 116, 106, and 106 beats min(-1), respectively. The corresponding energy expenditures were 3.90, 3.43, and 3.35 kcal min(-1). Loading the seed into the blower tank and broadcasting the seed were the most critical tasks for the seed broadcasting operation, with average heart rates of 124 and 136 beats min(-1), respectively. The highest energy expenditure of 418.38 kcal ha(-1) was observed for seed broadcasting, and the lowest energy expenditure of 127.96 kcal ha(-1) was for second plowing. The total seasonal human energy expenditure for rice cultivation was estimated to be 5810.71 kcal ha(-1), 55.7% of which was spent on pesticide spraying. Although the sample size in this study was relatively small, the results indicated that human energy expenditure per unit area (kcal ha(-1)) was positively linked to the average heart rate of the subjects and negatively linked to the field capacity. Thus, mechanization of certain tasks could decrease worker physical effort and fatigue and increase production.

Sero-prevalence of hepatitis B virus among middle to high socio-economic antenatal population in Sierra Leone.

This study was designed in order to find out the prevalence of HBV markers amongst pregnant women of middle and high socio-economic class in Sierra Leone. The aim was to determine the necessity and likely benefits of a scheme aimed at the vaccination of children of seropositive mothers who can afford the cost until mass immunisation is possible. A total of 302 women were studied. The seroprevalence rate formed in this study population was 6.2%. The proposed intervention would markedly reduce the HBV status in Sierra Leone, taking into account the high prevalent rate amongst this group. The low anti-HBs found in this population was suprisingly (5.1%); considering the high degree of antigenemia, this should be a subject for future research.

The prevalence of sickle cell trait in Sierra Leone. A laboratory profile.

Three thousand five hundred and twenty four (1527 male and 1997 female) samples were screened for the presence of the abnormal haemoglobin--Sickle Cell (HbS) between 1990-1993. 780 (22%) of these show sickle erythrocytes in a reduced oxygen environment. Electrophoretic differentiation of 344 samples positive from the metabisulphite screening test, revealed that 76 are of the homozygous form with 3 being HbSC. Noting the adverse consequences on the health status of those affected and the expense involved in the management of such patients, there is an urgent need for intervention.