Seasonal and annual variation in the diving behaviour of Hutton's shearwater (Puffinus huttoni)

ABSTRACT

With the development and implementation of tracking technology, we are now able to monitor the foraging behaviour of seabirds while at sea. Time-Depth Recorders (TDRs) were fitted to Hutton's shearwaters (Puffinus huttoni), an endangered endemic New Zealand species, to measure how diving behaviour varies over the breeding cycle. Hutton's shearwaters (～350?g) dive up to 339 times per day (average 68.8) at depths to 35?m (average 5.6?m), and for periods up to 60?s (average 19.2?s). Incubating birds dived deeper than birds feeding chicks, and a significant difference in diving depth and dive duration were detected at different times of the day. Neither dive frequency nor dive duration differed significantly between years, but there was some annual variation in dive depths. The temporal variation we observed in the diving behaviour of Hutton's shearwaters suggests they are likely to exploit different types of pelagic prey at different stages in their breeding cycle. With on-going changes in the marine environment, monitoring changes in feeding behaviour using TDRs may provide a way to assess environmental change and improve the conservation of this species.     

Diabetic impotence: studies of nocturnal erection during REM sleep.

Nocturnal erections were studied in 30 diabetic patients who complained of impotence and in 11 healthy volunteers. The maximum increase in penile circumference was measured by a penile strain-gauge and recorded on a portable tape-recorder; an external oculogram was recorded simultaneously to identify periods of rapid-eye-movement sleep. The technique gave reproducible results, was acceptable to patients, and was suitable for use in an oridnary hospital ward. Only six diabetics showed a maximum increase in penile circumference of under 15 mm, whereas all but one of the healthy subjects showed maximum increases above this value. Of the six diabetics, five complained of total impotence and had other features of autonomic neuropathy that suggested an organic basis for their impotence. The other patient complained of partial importence, which was probably caused by psychological factors. These findings suggest that the prevalence of organic impotence among diabetics has been overestimated.     

Inverse correlation between natural antitumor antibodies and tumor susceptibility in individual xid-bearing mice

Natural antibodies (NAb), natural killer (NK) cells and activated macrophages have all been implicated in the rejection of threshold syngeneic tumor inocula. Previous analysis of tumor susceptibility in normal versus inbred and F1 mice bearing the B cell deficiency associated with the xid mutation of CBA/N mice demonstrated an inverse relationship between the tumorigenicity of the RI-28, a radiation-induced leukemia of the CBA/H strain, and the pooled anti-RI-28 serum NAb levels in mice with the same genetic origins. No relationship with tumor susceptibility was seen with NK cell or in vivo activated macrophage cytolysis. Flow-cytometric determination of antitumor serum NAb bled from individual male and female (CBA/N X CBA/J)F1 mice 1 week prior to the threshold tumor inoculation has revealed extensive heterogeneity within the NAb levels of each sex. A comparative analysis of tumor fate with NAb activity revealed that tumors appeared in only 26.3% of animals with a mean fluorescence channel binding above 60 channels in contrast with 77.3% of animals with lower NAb levels. These data extend to the level of individual hosts the support for an inverse relationship between host NAb activity and tumor susceptibility. In addition, subsequent analysis of serum antitumor NAb levels, splenic NK cytolysis and in vitro lymphokine-activated macrophage activity with all three mediators originating from the same individual F1 mice showed no consistent correlations between these natural resistance activities, arguing for the exclusion of deficiencies in NK cell or macrophage function as the basis for the differential tumor susceptibility in individual F1 mice.