Population health, environment and economic development

This paper studies the role of income distribution and technology transfer in the process of economic development. A novel aspect of the model is that the composition of human capital as well as the level affect economic growth. Utilizing an overlapping-generations model in which income distribution changes endogenously, we present an economic explanation for why some countries could not start modern economic growth; why some countries took off but have apparently stopped growing after some time; and why some countries have successfully developed and continue to grow

Interspecific variation in plumage colour among birds: species recognition or light environment?

The traditional explanation for interspecific plumage colour variation in birds is that colour differences between species are adaptations to minimize the risk of hybridization. Under this explanation, colour differences between closely related species of birds represent reproductive character displacement. An alternative explanation is that interspecific variation in plumage colour is an adaptive response to variation in light environments across habitats. Under this explanation, differences in colour between closely related species are a product of selection on signal efficiency. We use a comparative approach to examine these two hypotheses, testing the effects of sympatry and habitat use, respectively, on divergence in male plumage colour. Contrary to the prediction of the Species Isolation Hypothesis, we find no evidence that sympatric pairs of species are consistently more divergent in coloration than are allopatric pairs of species. However, in agreement with the Light Environment Hypothesis, we find significant associations between plumage coloration and habitat use. All of these results remain qualitatively unchanged irrespective of the statistical methodology used to compare reflectance spectra, the body regions used in the analyses, or the exclusion of areas of plumage not used in sexual displays. Our results suggest that, in general, interspecific variation in plumage colour among birds is more strongly influenced by the signalling environment than by the risk of hybridization.

Trace organic compounds in the marine environment

Trace organic chemicals include a range of compounds which, due to a combination of their physico-chemical properties and toxicological implications, have been described as a serious threat to the biotic environment. A global treaty to regulate the manufacture and release of some of the most persistent trace chemicals has been promulgated and signed. The marine environment is an important sink for many trace chemicals, some of which accumulate in the marine food chain and in particular in marine mammals. With respect to the global distribution of trace organic chemicals, the levels of organohalogen compounds in the Southern Hemisphere are comparatively lower for a given environmental compartment and latitude compared to the Northern Hemisphere. A debate is currently evolving about the toxicity of alternative halogen substitutions such as bromine instead of chlorine and also of mixed halogen substitution. Recently a series of potentially natural bioaccumulative and persistent organohalogen chemicals have been found in marine mammals and turtles at levels in excess of those of anthropogenic trace organochlorines including PCBs and DDE. Little is known about the sources, behaviour and effects of natural trace organic chemicals. This manuscript presents an overview on the occurrence of trace organic chemicals in different compartments of the aquatic environment. Important knowledge gaps with regards to trace chemicals in the marine environment are presented. Crown Copyright (C) 2002 Published by Elsevier Science Ltd. All rights reserved.

Effects of paternal drinking, conduct disorder and childhood home environment on the development of alcohol use disorders in a Thai population

Aims To identify influences on the development of alcohol use disorders in a Thai population, particularly parental drinking and childhood environment. Design Case-control study. Setting A university hospital, a regional hospital and a community hospital in southern Thailand. Participants Ninety-one alcohol-dependents and 177 hazardous/harmful drinkers were recruited as cases and 144 non-or infrequent drinkers as controls. Measurements Data on parental drinking, family demographic characteristics, family activities, parental disciplinary practice, early religious life and conduct disorder were obtained using a structured interview questionnaire. The main outcome measure was the subject's classification as alcohol-dependent, hazardous/harmful drinker or non-/infrequent drinker. Findings A significant relationship was found between having a drinking father and the occurrence of hazardous/harmful drinking or alcohol dependence in the subjects. Childhood factors (conduct disorder and having been a temple boy, relative probability ratios, RPRs and 95% CI: 6.39, 2.81-14.55 and 2.21, 1.19-4.08, respectively) also significantly predicted alcohol dependence, while perceived poverty and ethnic alienation was reported less frequently by hazardous/harmful drinkers and alcohol-dependents (RPRS and 95% CIs = 0.34, 0.19-0.62 and 0.59, 0.38-0.93, respectively) than the controls. The relative probability ratio for the effect of the father's infrequent drinking on the son's alcohol dependence was 2.92 (95% CI = 1.42-6.02) and for the father's heavy or dependent drinking 2.84 (95% CI=1.31-6.15). Conclusions Being exposed to a light-drinking, father increases the risk of a son's alcohol use disorders exhibited either as hazardous-harmful or dependent drinking. However, exposure to a heavy- or dependent-drinking father is associated more uniquely with an increased risk of his son being alcohol-dependent. The extent to which this is seen in other cultures is worthy of exploration.

Structure of CcmG/DsbE at 1.14 angstrom resolution: High-fidelity reducing activity in an indiscriminately oxidizing environment

CcmG is unlike other periplasmic thioredoxin (TRX)like proteins in that it has a specific reducing activity in an oxidizing environment and a high fidelity of interaction. These two unusual properties are required for its role in c-type cytochrome maturation. The crystal structure of CcmG reveals a modified TRX fold with an unusually acidic active site and a groove formed from two inserts in the fold. Deletion of one of the groove-forming inserts disrupts c-type cytochrome formation. Two unique structural features of CcmG-an acidic active site and an adjacent groove-appear to be necessary to convert an indiscriminately binding scaffold, the TRX fold, into a highly specific redox protein.

Effect of a control burn on lizards and their structural environment in a eucalypt open-forest

The composition of an open-forest lizard assemblage in eastern Australia was examined before and after a low-intensity controlled fire and concurrently compared with that in an adjoining unburnt area. The effect of fire on the available structural environment and the habitat used by two focal species, Carlia vivax and Lygisaurus foliorum, was also examined. Lizard species richness was unaffected by the controlled burn as was the abundance of most species. C. vivax was the only species to display a significant reduction in abundance after fire. While the low-intensity fire resulted in significant changes to the available structural environment, there were no compensatory shifts in the habitat preferences of either C. vivax or L. foliorum. The reduction in abundance of C. vivax was congruent with this species' avoidance of burnt areas. C. vivax displayed a non-random preference for ground cover and litter cover, which were reduced in burnt areas. Changes in the availability of preferred structural habitat features are likely to contribute to changes in the abundance of some lizard species. Therefore, even low-intensity disturbances can have an impact on lizard assemblages if critical habitat features are lost or become limiting.

Adoption and maintenance of contour bunds and hedgerows in a dynamic environment - Experience in the Philippine uplands

The widespread adoption of soil conservation technologies by farmers (notably contour hedgerows) observed in Guba, Cebu City, Philippines, is not often observed elsewhere In the country. Adoption of these technologies was because of the interaction of such phenomena as site-specific factors, appropriate extension systems, and technologies. However, lack of hedgerow maintenance, decreasing hedgerow quality, and disappearance of hedgerows raised concerns about sustainability. The dynamic nature of upland farming systems suggests the need for a location-specific farming system development framework, which provides farmers with ongoing extension for continual promotion of appropriate conservation practices.

Mental health: How well are occupational therapists equipped for a changed practice environment?

No Abstract

Using crop simulation to generate genotype by environment interaction effects for sorghum in water-limited environments

Multi-environment trials (METs) used to evaluate breeding lines vary in the number of years that they sample. We used a cropping systems model to simulate the target population of environments (TPE) for 6 locations over 108 years for 54 'near-isolines' of sorghum in north-eastern Australia. For a single reference genotype, each of 547 trials was clustered into 1 of 3 'drought environment types' (DETs) based on a seasonal water stress index. Within sequential METs of 2 years duration, the frequencies of these drought patterns often differed substantially from those derived for the entire TPE. This was reflected in variation in the mean yield of the reference genotype. For the TPE and for 2-year METs, restricted maximum likelihood methods were used to estimate components of genotypic and genotype by environment variance. These also varied substantially, although not in direct correlation with frequency of occurrence of different DETs over a 2-year period. Combined analysis over different numbers of seasons demonstrated the expected improvement in the correlation between MET estimates of genotype performance and the overall genotype averages as the number of seasons in the MET was increased.

The effect of sodium chloride supplementation on the milk production of grazing Holstein Friesian cows during summer and autumn in a humid sub-tropical environment

Two studies were conducted to examine the effects of including NaCl at various rates in grain-based supplements for Friesian cows grazing established, dominant (>90%), rainfed kikuyu (Pennisetum clandestinum cv. Common) pastures during summer and autumn in a humid sub-tropical environment. In study 1 (19 January-27 March 1998), 48 cows (36 multiparous, 12 primiparous; 27-96 days postpartum) were allocated to one of four groups based on genetic merit, milk production, liveweight (LW) and days postpartum. They were fed (2.7 kg dry matter (DM) per cow, twice-a-day) one of four isoenergetic and isonitrogenous barley grain-based concentrates containing NaCl at concentrations (% as-fed) of either 0 (SC1), 1.1 (SC2), 2.2 (SC3) or 3.3 (SC4). Maximum temperature humidity index (THImax) was greater than or equal to78 during 50% of the experimental period. Concentrate NaCl content had no effect (P>0.05) on daily milk yield or LW change but daily yields of 4% fat corrected milk (FCM), fat and protein were higher (P0.05) among treatments at 7.6+/-1.24 kg DM per cow. In study 2 (18 January 1999-1 March 1999), 48 cows (32 pluriparous, 16 primiparous: 32-160 days postpartum) were fed (2.7 kg DM per cow twice-a-day) one of two isoenergetic and isonitrogenous barley grain-based concentrates containing NaCl at concentrations (% as-fed) of 0 (control) or 2.2 (HSC). THImax was greater than or equal to78 during 34% of days in the experimental period. Yields of milk, FCM, fat and protein were lower (P0.05) by concentrate NaCl content. These studies indicate that NaCl supplementation can be beneficial in terms of milk production during warm, humid conditions as opposed to milder conditions. (C) 2002 Elsevier Science B.V. All rights reserved.