Vitamin C status of vitamin A-deficient rats

IT was initially suggested that vitamin A-deficiency leads to an interference in the biosynthesis of ascorbic acid, because depletion of vitamin A was found to cause a fall in the tissue-levels of ascorbate and diminished urinary ascorbic acid excretion in animals1-3. Mapson4, however, concluded that lowered ascorbic acid-levels in vitamin A-deficient rats is due to inanition only, because he was able to show that following chloretone treatment vitamin A-deficient and pair-fed vitamin A normal rats excrete comparable amounts of ascorbic acid in their urine and that restriction of food intake reduces the urinary ascorbate even in the chloretone-treated normal rats. Results of our preliminary experiments reported here clearly indicate that the synthesis of ascorbic acid in rats is markedly reduced during vitamin A-deficiency.

Psychosocial processes of health behaviour change in a lifestyle intervention : Influences of gender, socioeconomic status and personality

Background: The onset of many chronic diseases such as type 2 diabetes can be delayed or prevented by changes in diet, physical activity and obesity. Known predictors of successful behaviour change include psychosocial factors such as selfefficacy, action and coping planning, and social support. However, gender and socioeconomic differences in these psychosocial mechanisms underlying health behaviour change have not been examined, despite well-documented sociodemographic differences in lifestyle-related mortality and morbidity. Additionally, although stable personality traits (such as dispositional optimism or pessimism and gender-role orientation: agency and communion) are related to health and health behaviour, to date they have rarely been studied in the context of health behaviour interventions. These personality traits might contribute to health behaviour change independently of the more modifiable domain-specific psychosocial factors, or indirectly through them, or moderated by them. The aims were to examine in an intervention setting: (1) whether changes (during the three-month intervention) in psychological determinants (self-efficacy beliefs, action planning and coping planning) predict changes in exercise and diet behaviours over three months and 12 months, (2) the universality assumption of behaviour change theories, i.e. whether preintervention levels and changes in psychosocial determinants are similar among genders and socioeconomic groups, and whether they predict changes in behaviour in a similar way in these groups, (3) whether the personality traits optimism, pessimism, agency and communion predict changes in abdominal obesity, and the nature of their interplay with modifiable and domain-specific psychosocial factors (self-efficacy and social support). Methods: Finnish men and women (N = 385) aged 50 65 years who were at an increased risk for type 2 diabetes were recruited from health care centres to participate in the GOod Ageing in Lahti Region (GOAL) Lifestyle Implementation Trial. The programme aimed to improve participants lifestyle (physical activity, eating) and decrease their overweight. The measurements of self-efficacy, planning, social support and dispositional optimism/pessimism were conducted pre-intervention at baseline (T1) and after the intensive phase of the intervention at three months (T2), and the measurements of exercise at T1, T2 and 12 months (T3) and healthy eating at T1 and T3. Waist circumference, an indicator of abdominal obesity, was measured at T1 and at oneyear (T3) and three-year (T4) follow-ups. Agency and communion were measured at T4 with the Personal Attributes Questionnaire (PAQ). Results: (1) Increases in self-efficacy and planning were associated with three-month increases in exercise (Study I). Moreover, both the post-intervention level and three-month increases (during the intervention) in self-efficacy in dealing with barriers predicted the 12-month increase in exercise, and a high postintervention level of coping plans predicted the 12-month decrease in dietary fat (Study II). One- and three-year waist circumference reductions were predicted by the initial three-month increase in self-efficacy (Studies III, IV). (2) Post-intervention at three months, women had formed more action plans for changing their exercise routines and received less social support for behaviour change than men had. The effects of adoption self-efficacy were similar but change in planning played a less significant role among men (Study I). Examining the effects of socioeconomic status (SES), psychosocial determinants at baseline and their changes during the intervention yielded largely similar results. Exercise barriers self-efficacy was enhanced slightly less among those with low SES. Psychosocial determinants predicted behaviour similarly across all SES groups (Study II). (3) Dispositional optimism and pessimism were unrelated to waist circumference change, directly or indirectly, and they did not influence changes in self-efficacy (Study III). Agency predicted 12-month waist circumference reduction among women. High communion coupled with high social support was associated with waist circumference reduction. However, the only significant predictor of three-year waist circumference reduction was an increase in health-related self-efficacy during the intervention (Study IV). Conclusions: Interventions should focus on improving participants self-efficacy early on in the intervention as well as prompting action and coping planning for health behaviour change. Such changes are likely to be similarly effective among intervention participants regardless of gender and educational level. Agentic orientation may operate via helping women to be less affected by the demands of the self-sacrificing female role and enabling them to assertively focus on their own goals. The earlier mixed results regarding the role of social support in behaviour change may be in part explained by personality traits such as communion.

Impact of dust on solar photovoltaic (PV) performance: Research status, challenges and recommendations

The peaking of most oil reserves and impending climate change are critically driving the adoption of solar photovoltaic's (PV) as a sustainable renewable and eco-friendly alternative. Ongoing material research has yet to find a breakthrough in significantly raising the conversion efficiency of commercial PV modules. The installation of PV systems for optimum yield is primarily dictated by its geographic location (latitude and available solar insolation) and installation design (tilt, orientation and altitude) to maximize solar exposure. However, once these parameters have been addressed appropriately, there are other depending factors that arise in determining the system performance (efficiency and output). Dust is the lesser acknowledged factor that significantly influences the performance of the PV installations. This paper provides an appraisal on the current status of research in studying the impact of dust on PV system performance and identifies challenges to further pertinent research. A framework to understand the various factors that govern the settling/assimilation of dust and likely mitigation measures have been discussed in this paper. (C) 2010 Elsevier Ltd. All rights reserved.

A review of hybrid rockets: present status and future potential

This paper discusses the potential of the hybrid rocket engine as a viable and attractive mode of propulsion for both space vehicles and missiles. Research and development work on this engine in other countries is presented and evaluated. The various advantages of a hybrid engine over solid and liquid engines and its problems are highlighted. It has been argued that because of the low technology needed in the development of the hybrid system, it constitutes a cost-and-time-effective propulsion system for several applications in space programmes as well as weapon systems. In support of this conclusion, experience on the developmental studies of a variable thrust 100 kg engine is presented. Some future possibilities for hybrid propulsion systems are cited.

The status and use of tree biomass in a semi-arid village ecosystem

The status of the tree biomass resource was investigated in Ungra, a semi-arid village ecosystem in South India. There were 57 tree species with 12 trees capita−1 and 35 trees ha−1. Multiple benefit yielding local tree species dominated the village ecosystem, while fuel only or single end use trees accounted for a small proportion of trees. The standing tree biomass is adequate to meet the requirement of biomass fuels for cooking only for about two years. Village tree biomass is presently being depleted largely for export to urban areas. Tree regeneration is now characterized by transformation from multiple-use local tree species to a few single-use species. A large potential exists for tree biomass production along field boundaries (bunds), stream banks and roadsides. Biomass estimation equations were developed for 10 species.

Status Survey of the Malabar Pied Hornbill in the Dandeli Region, Northern Western Ghats, India

The Malabar Pied Hornbill, Anthracoceros coronatus, is a near threatened species, endemic to the tropical deciduous forests of central and southern India and Sri Lanka. The Dandeli region in Karnataka (India) is believed to be the last stronghold of this species in the Western Ghats biodiversity hotspot. Being a rapidly developing area with a growing human population, the threats to this species and their habitat are mounting, especially due to a large number of hydroelectric projects and habitat fragmentation caused by paper and plywood industries. This study evaluated the change in population status of the Malabar Pied Hornbill over a 23 year period and defined priorities for the long term conservation and monitoring of hornbills in Dandeli. Encounter rates of hornbills were also analysed in relation to the density and species richness of trees and fruiting trees, basal area, canopy cover and distance from river. Hornbill encounters were not significantly different compared to the earlier study carried out by Reddy in 1988, but were significantly different across the five sites in the current study. Higher numbers of hornbills were encountered closer to the river, but these results were only marginally significant. The mean numbers of hornbills recorded at the two roost sites identified in Dandeli were 26 +/- 4.47 (n=16 counts) and 31.78 +/- 3.53 (n=14 counts) respectively. The study also helped build local awareness about the species, train local Forest Department staff in monitoring hornbills and develop a management plan for its conservation.

The Asian elephants Elephas maximus of Cat Tien National Park, Vietnam: status and conservation of a vanishing population

This study updates the status and conservation of the Endangered Asian elephant Elephas maximus in Cat Tien National Park, Vietnam. Line transect indirect surveys, block surveys for elephant signs, village surveys of elephant-human conflict incidents, guard-post surveys for records of sightings, and surveys of elephant food plants were undertaken during the dry and wet seasons of 2001. A minimum of 11 elephants and a maximum of 15-17 elephants was estimated for c. 500 km2 of the Park and its vicinity. The elephants are largely confined to the southern boundary of the Park and make extensive use of the adjoining La Nga State Forest Enterprises. During the dry season the elephants depend on at least 26 species of wild and cultivated plants, chiefly the fruits of cashew. Most of the villages surveyed reported some elephant-human conflict. Two adult male elephants seem to cover a large area to raid crops, whereas the family groups restrict themselves to a few villages; overall, the conflict is not serious. Since 2001 there have been no reports of any deaths or births of elephants in the Park. We make recommendations for habitat protection and management, increasing the viability of the small population, reducing elephant-human conflicts, and improving the chances of survival of the declining elephants of this Park. The Government has now approved an Action Plan for Urgent Conservation Areas in Vietnam that calls for the establishment of three elephant conservation areas in the country, including Cat Tien National Park.