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The purpose of this study was to explore the differences in initial status and growth trajectories of college students who did and did not participate in a voluntourism experience. A key objective of the study was to explore the backgrounds of the participants, comparing them to similar nonvoluntourists, to better understand what compelled them to spend their spring break engaged in community service in a distant location. The participants were 617 students at a university in the Midwestern United States, half of whom participated in a voluntour. Voluntourists reported higher levels of yearly civic engagement, civic attitude, openness, compassion, cognitive drive and reflectivity. The developmental disparities evident before the tour continued to grow over the course of five weeks. Implications for marketing, program design and education are discussed within the context of the burgeoning voluntourism industry.
The concept of ecological exchangeability, together with genetic exchangeability, is central to both the Cohesion Species Concept as well as to some definitions of Evolutionarily Significant Units. While there are well-established criteria for measuring genetic exchangeability, the concept of ecological exchangeability has generated considerable confusion. We describe a procedure that uses the complementary strengths, while recognising the limitations, of both molecular genetic data and ecological experiments to determine the ecological exchangeability of local populations within a species. This is the first synthesis of a combined approach (experiments and genetics) and the first explicit discussion of testing ecological exchangeability. Although it would be ideal to find functional genes that interact to influence quantitative traits resulting in ecological differences (e.g. growth, size, fecundity), we suggest that our current knowledge of functional markers is too limited for most species to use them to differentiate adaptively different local populations. Thus, we argue that ecological experiments using whole organisms combined with neutral markers that indicate evolutionary divergence, provide the strongest case for detecting adaptive differences among local populations. Both genetic divergence and ecological experiments provide the best information for infering ecological exchangeability. This procedure can be used to decide which local populations should be preserved to maintain intraspecific variation and to determine which populations would enhance captive-breeding programs, augment endangered local populations and could best be used to re-introduce native species into historically occupied areas.
The aim of this study was to determine the effect of acute plasma volume expansion on arterial blood-gas status during 6.5 min strenuous cycling exercise comparing six athletes with and six athletes without exercise-induced arterial hypoxaemia (EIAH). We hypothesized that plasma volume expansion could improve arterial oxygen pressure in a homogeneous sample of athletes - those with EIAH. In this paper we have extended the analysis and results of our recently published surprising findings that lengthening cardiopulmonary transit time did not improve arterial blood-gas status in a heterogeneous sample of endurance cyclists. One 500 ml bag of 10 % Pentastarch (infusion condition) or 60 ml 0.9 % saline (placebo) was infused prior to exercise in a randomized, double-blind fashion on two different days. Power output, cardiac output, oxygen consumption and arterial blood gases were measured during strenuous exercise. Cardiac output and oxygen consumption were not affected by acute hypervolaemia. There were group × condition interaction effects for arterial oxygen pressure and alveolar-arterial oxygen pressure difference, suggesting that those with hypoxaemia experienced improved arterial oxygen pressure (+4 mmHg) and lower alveolar-arterial oxygen pressure difference (-2 mmHg) with infusion. In conclusion, acute hypervolaemia improves blood-gas status in athletes with EIAH. The impairment of gas exchange occurs within the first minute of exercise, and is not impaired further throughout the remaining duration of exercise. This suggests that arterial oxygen pressure is only minimally mediated by cardiac output. Experimental Physiology (2003) 88.4, 555-564.
This paper reviews the results of several years' study by
a multidisciplinary team comprising geneticists,
physiologists, ecologists and statisticians of abiotic stress tolerance
barley. The strategy involves genetic
fingerprinting of wild barley lines (Hordeum spontaneum C.
Koch) from a range of habitats and testing these for
responses to abiotic stresses under controlled conditions. Multiple regression
analysis is used to identify genetic
markers associated with experimentally determined stress responses. These
are related to site-of-origin
ecogeographic data and used to identify areas of useful wild variation.
associated with traits of interest
can be mapped in genetic mapping populations, revealing areas of the barley
genome carrying genes controlling
stress responses. This paper highlights our work on associations of amplied
fragment length polymorphisms with
salt tolerance and describes some initial results of the use of SSRs in
studying drought tolerance in barley.
A case of neonatal myasthenia gravis is reported in the infant of an asymptomatic thymectomized mother with comparably elevated acetylcholine receptor (AChR) antibody titers. The mother remained asymptomatic despite elevated antibody titers while the infant became asymptomatic in association with the disappearance of the AChR antibody. It is suggested that the AChR antibody plays an essential role in the development of neonatal myasthenia gravis. It is also suggested that a thymic factor is necessary for the development of clinical symptomatology accounting for the lack of correlation between the clinical state of the mother and infant.
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