No evidence for parental age effects on offspring leukocyte telomere length in free-living Soay sheep.

In humans, the effect of paternal age at conception (PAC) on offspring leukocyte telomere length (LTL) is well established, with older fathers thought to pass on longer telomeres to their offspring in their sperm. Few studies have looked for PAC effects in other species, but it has been hypothesised that the effect will be exacerbated in polygamous species with higher levels of sperm competition and production. We test for maternal (MAC) and paternal age at conception effects on offspring LTL in Soay sheep, a primitive breed experiencing strong sperm competition. We use qPCR to measure relative telomere length in 389 blood samples (n = 318 individuals) collected from an unmanaged population of sheep on St Kilda, where individual age and parentage are known. We find no evidence that either MAC or PAC are associated with LTL in offspring across the age range, or when considering only young lambs (n = 164). This is the first study to test for parental age effects on offspring LTL in a wild mammal population, and the results contrast with the findings of numerous human studies that find a PAC effect, as well as predictions of a stronger PAC effect in polygamous species.

Long-term stability after treatment with removable appliances.

The long-term stability of 34 cases treated by one operator in general dental practice with removable appliances was investigated using clinical, model and radiographic data. The cases were divided into three groups; Class I, Class II and Class III, and were ranked according to the stability and type of result obtained. The results indicated that good interdigitation of teeth was an important factor in stability.

The supply of volunteer labor: the case of hospitals.

Little is known about the labor market for volunteers, but even less is known about the supply of volunteers to particular industries. This article examines the supply of volunteer labor to one industry, hospitals, and the choices that volunteers make among hospitals with different ownership attributes. Survey data of volunteers at four hospitals located in Madison, Wisconsin, are used to estimate the importance of a number of factors influencing people's willingness to volunteer at hospitals. We found that job opportunities in the labor market and tax rates affect the supply of volunteers. We also found that volunteers are not indifferent to the type of hospital at which they volunteer; a federal government hospital, a nonprofit state-owned teaching hospital, and other nonprofit hospitals were not perfect substitutes in the eyes of individual volunteers in our study.