A gradient-layer calorimeter for measurement of energy expenditure of infants.

We have developed and validated a gradient-layer calorimeter for direct measurement of energy expenditure of preterm infants. Infant calorimeters must be operated and tested differently from adult calorimeters, because the calorimeter must be warmed during operation to limit heat loss from the infant, the calorimeter wall temperature (which is selected on the basis of the infant's maturity) must be precisely controlled, and energy expenditure (heat output) is typically < 10 W. We calibrated our calorimeter by varying the heat produced by a dry source (manikin or light bulb) with airflow (n = 42) and without airflow (n = 8) at various water jacket temperatures (n = 7) and by a wet source (combustion of ethyl alcohol) with airflow (n = 9).

[The school child carrying heavy burdens].

In 163 Viennese pupils in standard 1 to 8, the weight of the schoolbag, the bodyweight and the ratio of these two parameters were examined in order to describe the amount of burden carried by those children. The results were: 1. The weight of the schoolbag war 4.