Browsing by Author "Alexander, Graham"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Open Access
    Eating disorders and excessive exercise : a comparison of high-impact aerobics and road running
    (1994) Alexander, Graham; Le Grange, Daniel
    Excessive exercise has always been a noted characteristic of patients with anorexia nervosa. Recent research has focused on the impact of physical activities, depending on their nature, towards the susceptibility of disordered eating or excessive exercise. The present study explores the hypothesis that when the pressure to be fit overrides the pressure to be thin, t his will lead to disturbed attitudes and behaviours towards exercise. When the pressure to be thin overrides the pressure to be fit, subjects will be more susceptible to the development of eating problems. Further, it is hypothesised that the prevalence of eating pathology is higher among the female subjects, while males are more inclined to be susceptible to exercising excessively. In order to examine these hypotheses, three independent groups, matched for age and gender, were studied. High-impact Aerobics participants (n =59) and Road Runners (n = 85) were chosen as they represented respectively : an athletic group that emphasises thinness and an athletic group that places an emphasis on fitness. A control group (n = 61) was also recruited. In terms of the results, a statistical analysis revealed that the high-impact aerobics group reflected greater eating, weight and body shape concerns than the other two groups, while the road runners were more preoccupied with exercise concerns than the other two groups. In a gender comparison, the females were more preoccupied than males with eating, weight and body shape concerns, while both genders reported similar exercise concerns. The data suggest that road runners are not necessarily vulnerable to the development of eating disorders merely due to their physical activity.
  • Thumbnail Image
    Item
    Open Access
    Tortoise mortalities along fences in the southeastern Karoo, South Africa
    (2017) Macray, Matthew; Lee, Alan; Alexander, Graham; Ryan, Peter G
    Fencing, particularly electric fencing, is widely used across South Africa for livestock and game ranching practices. Recent studies found that leopard tortoises (Stigmochelys pardalis) are more prone to dying from electrocution along electric fences than any other taxa. However, no studies have quantified tortoise mortality along non-electric fences or assessed the impact of fence structure. With South Africa being home to more tortoise species than anywhere else in the world, thus is a conservation concern. This study quantifies tortoise mortalities associated with electrified and non-electrified fences and relates these rates to fence structure (mesh or strand). Open veld transects are used as controls to estimate background mortality. This study also reports the distribution and abundance of different fence types along 2200 km of roads in the southeastern Karoo, allowing the cumulative impacts of different fence types to be estimated. All fence types had significantly higher tortoise mortalities than open veld transects. Leopard tortoise mortalities were significantly higher along electric fences than non-electric fences. Despite forming only approximately 4% of all roadside fencing, electric fences account for 56% of leopard tortoise mortalities. This study validates concern for increased electric fence use in the future and the potential impacts on leopard tortoises. When considering the current abundance of fence types and their associated mortalities, the total number of leopard tortoise mortalities along electric and non-electric fences are similar. Angulate tortoise (Chersina angulata) mortalities were significantly higher along mesh fences than strand fences, but did not differ between electric and non-electric fences. Angulate tortoises appear to wedge themselves in mesh fences and are unable to escape. This study highlights the current threat of non-electric fencing on tortoises as no similar findings have been reported. These additional tortoise mortalities should be considered alongside other emerging threats when questioning the longevity of these tortoise populations, not only in the Karoo, but globally. The implementation and practicality of previously suggested mitigation strategies are discussed and alternative mitigation strategies are suggested. This study concludes that raising of the electric strands is impractical and the implementation of rock aprons are ineffective. Live tortoises displayed active behavior when temperature was above 20 °C, thus thermostatic switches for electric fences could potentially reduce tortoise mortalities without compromising fences function.