ABSTRACT
An electronic device to record the valvular movements of clams was fabricated using a Hall effect transducer. It was used to record the responses of Anadara granosa, an arcid clam harvested from coastal waters of Bombay, to a chemical toxicant (10 ppm CuSO4) after 96 hr exposure to naphthalene (5, 10 and 15 ppm). The clams exposed to naphthalene did not respond to the presence of a chemical toxicant (10 ppm CuSO4) while the control clams responded and closed their shells rapidly.
Subject(s)
Animals , Behavior, Animal/physiology , Bivalvia/physiology , ElectronicsABSTRACT
BACKGROUND. Magnesium is required in higher quantities, during the phase of rapid growth, in children. Its level in the ground water in Kerala is low. This can cause magnesium deficiency especially in children from the lower socio-economic groups who also suffer from nutritional insufficiency. METHODS. We compared the serum and erythrocyte magnesium levels of school children from high and low (agricultural labourers and fisherfolk) socio-economic groups. These levels were determined using atomic absorption spectrophotometry. Body mass indices and haemoglobin levels were used as indirect measures of nutritional status. RESULTS. Serum and erythrocyte magnesium levels were significantly lower in both boys and girls from low socio-economic groups who also had lower body mass indices. CONCLUSION. Nutritional insufficiency is prevalent in children from the low socio-economic groups and is associated with low serum and erythrocyte magnesium levels.