Long-term 24-hour rest-activity pattern of sheep in stalls and in the field

Summary Motor activity of sheep was continuously recorded for 2–3 weeks with an ambulatory monitoring device. Recordings were obtained from free-ranging animals in the field and from animals maintained under various controlled conditions in stalls. The sheep were diurnal under all conditions. While the daily amount of activity and the frequency of rest episodes showed only small differences between the conditions, the rest-activity pattern showed prominent differences. The pattern differed particularly between the field and the stalls. In the field, activity started to increase one hour after dawn, reaching a first maximum towards noon; a second, higher peak in the evening was followed by a rapid decline after dusk. In the stalls the onset and offset of activity was more abrupt; activity peaks coincided with feeding and human activity; the onset of rest with lights off. Activity was lowest and rest most prominent in those stalls where the animals were most isolated from human influence.     

Forecasting and trading strategies based on a price trend model

In this paper, we consider the price trend model in which it is assumed that the time series of a security's prices contain a stochastic trend component which remains constant on each of a sequence of time intervals, with each interval having random duration. A quasi‐maximum likelihood method is used to estimate the model parameters. Optimal one‐step‐ahead forecasts of returns are derived. The trading rule based on these forecasts is constructed and is found to bear similarity to a popular trading rule based on moving averages. When applying the methods to forecast the returns of the Hang Seng Index Futures in Hong Kong, we find that the performance of the newly developed trading rule is satisfactory. Copyright © 2000 John Wiley & Sons, Ltd.     

IFT80, which encodes a conserved intraflagellar transport protein, is mutated in Jeune asphyxiating thoracic dystrophy

Jeune asphyxiating thoracic dystrophy, an autosomal recessive chondrodysplasia, often leads to death in infancy because of a severely constricted thoracic cage and respiratory insufficiency; retinal degeneration, cystic renal disease and polydactyly may be complicating features. We show that IFT80 mutations underlie a subset of Jeune asphyxiating thoracic dystrophy cases, establishing the first association of a defective intraflagellar transport (IFT) protein with human disease. Knockdown of ift80 in zebrafish resulted in cystic kidneys, and knockdown in Tetrahymena thermophila produced shortened or absent cilia.