An explanatory model of underwater adaptation

The underwater environment is an extreme environment that requires a process of human adaptation with specific psychophysiological demands to ensure survival and productive activity. From the standpoint of existing models of intelligence, personality and performance, in this explanatory study we have analyzed the contribution of individual differences in explaining the adaptation of military personnel in a stressful environment. Structural equation analysis was employed to verify a model representing the direct effects of psychological variables on individual adaptation to an adverse environment, and we have been able to confirm, during basic military diving courses, the structural relationships among these variables and their ability to predict a third of the variance of a criterion that has been studied very little to date. In this way, we have confirmed in a sample of professionals (N = 575) the direct relationship of emotional adjustment, conscientiousness and general mental ability with underwater adaptation, as well as the inverse relationship of emotional reactivity. These constructs are the psychological basis for working under water, contributing to an improved adaptation to this environment and promoting risk prevention and safety in diving activities.

Risk management for scuba diving operators on Australia's Great Barrier Reef

Australia's Great Barrier Reef is one of the world's most popular scuba diving destinations. Unfortunately, a series of recent diving injuries and deaths has tarnished the region's safety record. In particular, media attention surrounding the disappearance of American divers Thomas and Eileen Lonergan has focused attention on dive operators' legal responsibilities and the consequences of failing to discharge their duty of care to customers. This paper briefly examines the relevant Australian law for recreational diving operations, and reviews risk management strategies that may reduce or prevent the occurrence of future problems. (C) 2000 Elsevier Science Ltd. All rights reserved.

The teaching of History meets its past: memories of teaching staff during the civil-military dictatorship

The civil-military dictatorship, which took power in 1964, influenced the daily activities of schools and teachers. Many transformations occurred during this period, including the new legislation enacted under Law 5692/71 and changes which occurred due to the vigilance which teachers felt when working. The memories analyzed here of teachers from public schools in Sao Paulo show different perceptions of this surveillance, involving various forms of acceptance or resistance. The purpose of this article is to show that although there was no direct repression of schools, unlike in the universities, teachers at the elementary school also felt constrained and this can be seen in their educational practices and teaching concepts.

Diving behaviour of two Australian bimodally respiring turtles, Rheodytes leukops and Emydura macquarii, in a natural setting

Time-depth recorders were used to investigate the diving performance and behaviour of two bimodally respiring turtle species, Rheodytes leukops and Emydura niacquarii, known to have a high and low reliance on aquatic respiration, respectively. Significant differences in diving performance between R. leukops and E. macquarii were observed in the number of dives/day (39.3 +/- 5.38 vs 112.2 +/- 11.73 dives/day; mean +/- SE), mean dive length (33.1 +/- 7.33 min vs 9.6 +/- 2.26 min) and maximum dive length (623 +/- 104.74 min vs 67.1 +/- 8.14 min), respectively. Differences in diving performance between R. leukops and E macquarii are attributed to the species' reliance (or lack thereof) upon aquatic respiration. Rheodytes leukops displayed a weak bimodal pattern of increased surfacing frequency in the early morning (05:00-07:00) and late afternoon (14:00-18:00), while E. macquarii displayed a strong bimodal pattern of elevated surfacing frequency over similar time periods. Daily patterns of increased surfacing frequency for both species failed to correlate with fluctuating aquatic Po-2 levels or water temperature, and may instead be explained by the heightened activity levels of both species during twilight.

Effect of water temperature and oxygen levels on the diving behavior of two freshwater turtles: Rheodytes leukops and Emydura macquarii

Rheodytes leukops is a bimodally respiring turtle that extracts oxygen from the water chiefly via two enlarged cloacal bursae that are lined with multi-branching papillae. The diving performance of R. leukops was compared to that of Emydura macquarii, a turtle with a limited ability to acquire aquatic oxygen. The diving performance of the turtles was compared under aquatic anoxia (0 mmHg), hypoxia (80 mmHg) and normoxia (155 mmHg) at 15, 23, and 30degreesC. When averaged across all temperatures the dive duration of R. leukops more than doubled from 22.4 +/- 7.65 min under anoxia to 49.8 +/- 19.29 min under normoxic conditions. In contrast, aquatic oxygen level had no effect on the dive duration of E. macquarii. Dive times for both species were significantly longer at the cooler temperature, and the longest dive recorded for each species was 538 min and 166 min for R. leukops and E. macquarii, respectively. Both species displayed a pattern of many short dives punctuated by occasional long dives irrespective of temperature or oxygen regime. Rheodytes leukops, on average, spent significantly less time (42 +/- 2 sec) at the surface per surfacing event than did E. macquarii (106 +/- 20 sec); however, surface times for both species were not related to either water temperature or oxygen level.