A classic example of a sexually selected trait, the deep fork tail of the barn swallow Hirundo rustica is now claimed to have evolved and be maintained mainly via aerodynamic advantage rather than sexually selected advantage. However, this aerodynamic advantage hypothesis does not clarify which flight habits select for/against deep fork tails, causing diversity of tail fork depth in hirundines....

A comparative study of artificial neural network (ANN) and multiple regression is made to predict the fat tail weight of Balouchi sheep from birth, weaning and finishing weights. A multilayer feed forward network with back propagation of error learning mechanism was used to predict the sheep body weight. The data (69 records) were randomly divided into two subsets. The first subset is the train...

rade control structures are used to control bed erosion in steep small rivers mostly in the mountains. scour downstream of this structure can lead to failure. over the past years, the effect of different variables on this phenomena have been studied, however the effect of upward seepage which is common due to head difference of the banks water table or water surface level between the upstream a...

The aim of this study was to determine in the marsupial Sminthopsis crassicaudata 1) the effect of leptin on food intake, body fat stores, and metabolism and 2) whether leptin can prevent a diet-induced increase in adiposity. In response to 21 days of feeding with mealworms (2.99 kcal/g, 30% fat), body weight ( P < 0.0001) and tail width ( P < 0.0001) increased, compared with control animals fe...

Dispersal has long been recognized as a crucial factor affecting population dynamics. Several studies on long-distance dispersal revealed a peculiarity now widely known as a problem of "fat tail": instead of the rate of decay in the population density over large distances being described by a normal distribution, which is apparently predicted by the standard diffusion approach, field data often...

leptin (lep), the expression product of the obese gene produced primarily in the adipose tissue, is related to feed intake, growth and lipid metabolism. the aim of this study was to study the possible association between polymorphism of the lep gene with growth and carcass traits among three iranian sheep breeds of the shal, zandi and zel varieties. a total of 180 purebred animals of the shal, ...