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Various countries have permanent research bases in Antarctica that are manned year-round by a few members of an expedition team, facing extremes of temperature with the associated hardships. Acclimatisation to such an environment is associated with pyschophysiological changes along with alterations in sleep patterns. The present study was undertaken to explore the changes in sleep patterns of six members of the Indian expedition team during their winter stay at Maitri, the permanent research station of India in Antarctica. The mean (+/- SEM) age, height and weight of the subjects were 35.7 +/- 2.32 years, 168.3 +/- 2.37 cm and 71.0 +/- 1.88 kg, respectively. Polysomnographic sleep recordings were obtained as baseline data in November 2004 in Delhi (altitude 260 m, latitude 29 degrees N, longitude 77 degrees E); data on the same parameters were collected at Maitri, Antarctica (altitude 120 m, latitude 70 degrees 45' 39'' S, longitude 11 degrees 44' 49'' E) from January to December 2005. A one-way analysis of variance with repeated measures showed a significant variation with time (month effect) in most of the sleep parameters recorded. Total sleep time decreased from Delhi baseline values in all months, sleep efficiency decreased significantly during winter months, duration of waking period after sleep onset increased significantly in winter, sleep latency increased immediately after exposure in January, stages 3 and 4 (slow wave sleep) reduced during dark winter months, whereas stages 1 and 2 and rapid eye movement sleep increased during dark winter months. This study observed a prevailing general trend of sleep disturbances amongst overwintering members in a modern Antarctic station.

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High temperature stress is major constraint to bread wheat (Triticum aestivum L. Em. Thell) production. Generation of information on the effect of high temperature stress on various traits may be helpful for developing thermotolerance bread wheat variety. An experiment was conducted on a set of 10 diverse genotypes, their 45 F1s and F2s for identification of high temperature stress genotype. The experiment was conducted under normal and late sown condition. The parent HD 2851, P8W 520, and HS 448, and the crosses HS 448 × PBW 520, UP 2614 × K 209 and PBW 520 × HD 2851 for grain yield per plant were least affected under late sown conditions. Heat stress intensity (Dvalue) clearly indicated that grain yield per pant biological yield per plant and grain yield per spike suffered revively under late sown conditions. Keywords: Bread wheat; heat susceptibility index; tolerant genotypes. DOI: http://dx.doi.org/10.3329/bjar.v36i3.9270 BJAR 2011; 36(3): 415-426

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A group of 221 male healthy volunteers of Indian Army were the subjects of the study. The baseline parameters of skeletal health were measured during their residency at an altitude of 3542 m. These subjects were then taken to an extreme altitude (EA, 5400-6700 m) where they stayed for about 4 months. The study parameters were repeated following their de-induction (DI) to 3542 m. On random selection, a subgroup was constituted from the above mentioned volunteers for detailed investigations on various bone turnover markers. Results of this study indicate a loss of body weight after DI from EA. The bone impairment was detected at the proximal phalanx, which is known to undergo early morpho-structural changes associated with bone resorption. The intact parathyroid hormone (i-PTH) levels showed a significant increase, while alkaline phosphatase (ALP) and bone specific alkaline phosphatase (BAP) activities declined significantly after DI from EA. This elevation in i-PTH might be required for maintenance of blood Ca level. 25 (OH) Vitamin D3 (25VitD) and calcitonin (CT) also showed a significant decline, which may suggest a negative impact on bone formation during sojourn at EA. The causes of deterioration of skeletal health at EA although are poorly understood but may be due to acute hypoxemia arising from extreme hypobaric hypoxia prevalent at extreme altitude.

These observations suggest that prolonged residency under hypoxic environment is associated with a decline in both bone formation and bone resorption markers, reflecting a lower bone turnover at HA.