Postweaning duration and body composition changes in Southern elephant seal (Mirounga leonina) pups at King George Island.

Weaning mass in southern elephant seals is highly variable, the heaviest pups being three times as heavy as the lightest ones. After weaning, pups undergo an extensive postweaning period in which they draw on their reserves. To quantify the energy expenditure during the postweaning period, changes in mass, body composition, and postweaning duration were measured in southern elephant seals at King George Island, South Shetland Islands, Antarctica. Overall, mean pup weaning mass was 154 +/- 26 kg (n=117) and did not differ between sexes. Mean minimum postweaning duration was 42.5 +/- 7.5 d. Heavier animals at weaning had lower mass-specific mass loss rates than lighter ones, and a faster depletion of body reserves was associated with a shorter postweaning period. The proportion of body mass represented by fat at weaning was 37% +/- 4% (n=47) and did not differ between sexes. Of these pups, 36 were recaptured after a mean period of 36 d after weaning. On average, total mass loss measured in these animals (39 kg) was composed of 39% water, 47% fat, and 12% protein. The composition of mass loss was not significantly different between sexes and was not related to weaning mass or total body energy reserves. However, fatter animals at weaning lost more fat per kilogram lost than thinner ones. Late in the fast, males and females appeared to be in a similar body condition. Nevertheless, the overall proportion of body mass represented by fat at this time was lower than that presented by the same animals at weaning. We estimated that during the postweaning period pups lost, on average, 30% of their mass at weaning. This comprised approximately 35% of the energy and 32% of the fat in the pup's body.

Update on trauma system development in the United States.

BACKGROUND: Two previous reports, in 1987 and 1993, have tracked trauma system development in the United States. This report updates the current status of trauma systems in the United States. METHODS: All state emergency medical service directors (including the District of Columbia) were surveyed regarding the existence of trauma systems in their states, including the presence of eight essential criteria of trauma system development that have been the focus of the two previous studies. Data were analyzed and compared with results previously published in the two reports. RESULTS: Five states met all eight essential development criteria, 28 states met six or seven criteria, and another 10 states met between one and five criteria. In the 1993 study, 18 states met six or more criteria. In 1987, 22 states reported meeting four or more criteria. CONCLUSION: There has been significant progress, when compared with 1987 and 1993 evaluations in the number of states reporting the presence of trauma systems and meeting six or more key criteria. Recent progress may be due to federal assistance for trauma system development available from 1991 until 1995.

Immunoglobulin M serum levels in females and pups of southern elephant seal (Mirounga leonina) during the suckling period.

This paper reports Immunoglobulin M (IgM) levels in serum samples from eight female-pup pairs of southern elephant seals (Mirounga leonina), at King George Island, Antarctica. IgM levels were determined on sera obtained from sequential sampling throughout the suckling period (approximately 23 days). The IgM concentration in southern elephant seal serum was measured by single radial immunodiffusion on agarose plates. Female IgM levels (123.5-613.0 mg/dL, n = 8) were significantly higher than pup levels (5.9-123.6 mg/dL, n = 8). Both groups showed an increasing trend throughout the entire suckling period, with significant differences in relation to stages of lactation. Pup IgM levels on the first day of life (mean +/- SD, 7.6 +/- 2.9 mg/dL, n = 3) suggest that endogenous synthesis takes place before birth.

Immunoglobulin A levels in southern elephant seal (Mirounga leonina) milk during the suckling period.

Immunoglobulin A (IgA) levels in milk samples from southern elephant seals at King George Island, Antarctica are reported. IgA levels were determined throughout the suckling period (approximately 23 days). The IgA concentration in southern elephant seal milk was lower than in other mammals and, unlike most mammalian milk, was not high during early lactation. There was not a definite pattern in IgA levels, which fluctuated within narrow limits throughout the suckling period (mean +/- SD, 30.81 +/- 6.38 mg IgA/100 g milk). If IgG was present, its level was too low to be detected by the method used. This is the first evidence in Southern elephant seal of the possibility of transmission of passive immunity after birth involving secretion of IgA in the milk.

Effect of detector displacement in confocal imaging systems.

Confocal imaging systems rely on the use of an accurately positioned axial point detector. We discuss in this paper the effects on the various imaging modes of using a misaligned pinhole. We pay particular attention to the form of the transfer function and the depth discrimination property. A simple model of a thick edge type object is introduced, and it is found that in certain cases a degree of detector offset may be used to advantage in determining the position of the edge.

Size of the detector in confocal imaging systems.

We consider the role of the detector size in the imaging of confocal systems. We introduce a criterion for detector size to give true confocal operation and show that the lateral resolution is considerably more sensitive to detector size than is the depth-discrimination or optical-sectioning property.