Sibling dynamics and sport expertise.

Family members are known to be highly influential in the development of sport expertise. To date, much of the research in this area has focused on parents, with less known about sibling influences on expertise. This investigation explored associations between sport expertise, sibling characteristics, and sibling participation in sport and physical activity. Athletes representing three skill levels provided details of sibling characteristics and participation in sport and physical activity via the Developmental History of Athletes Questionnaire. Elite athletes were more likely to be later-born children, while pre-elite and non-elite athletes were more likely to be first-born. Compared with siblings of non-elite athletes, siblings of elite athletes were more likely to have participated in regular physical activity and were more likely to have participated in sport at the pre-elite and elite levels. These results suggest siblings may play a key role in sport expertise development.

Metabolic limits on dive duration and swimming speed in the southern elephant seal Mirounga leonina.

The ability of air-breathing marine predators to forage successfully depends on their ability to remain submerged. This is in turn related to their total O(2) stores and the rate at which these stores are used up while submerged. Body size was positively related to dive duration in a sample of 34 adult female southern elephant seals from Macquarie Island. However, there was no relationship between body size and dive depth. This indicates that smaller seals, with smaller total O(2) stores, make shorter dives than larger individuals but operate at similar depths, resulting in less time being spent at depth. Nine adult female elephant seals were also equipped with velocity time depth recorders. In eight of these seals, a plot of swimming speed against dive duration revealed a cloud of points with a clear upper boundary. This boundary could be described using regression analysis and gave a significant negative relationship in most cases. These results indicate that metabolic rate varies with activity levels, as indicated by swimming speed, and that there are quantifiable limits to the distance that a seal can travel on a dive of a given swimming speed. However, the seals rarely dive to these physiological limits, and the majority of their dives are well within their aerobic capacity. Elephant seals therefore appear to dive in a way that ensures that they have a reserve of O(2) available.

The evolution of the concept of the use of surgical castration in the palliation of breast cancer in pre-menopausal females.

The understanding of the association of mammalian ovarian function with lactation was common knowledge to dairy-men early in the 19th century or earlier. This thesis reviews the application of these empiric observations to lactation in humans by Beatson of Glasgow, supported by his preliminary laboratory investigations. Beatson noted the cellular anatomic similarity between pre-gestational breast and carcinoma. This study reviews the progressive development of the successful clinical application of castration for the control of inoperable breast cancer by Beatson in pre-menopausal women in 1895. The review terminates with its leading to the monumental work of Huggins in 1941.

The role of conjugative transposons in the Enterobacteriaceae.

Although widely studied in gram-positive Streptococci and in the gram-negative Bacteroides, there is a scarcity of information on the occurrence and nature of conjugative transposon-like elements in the well-studied Enterobacteriaceae. In fact, some of the major reviews on conjugative transposons prior to 1996 failed to mention their occurrence in this group. Recently, their presence has been reported in Salmonella, Vibrio and Proteus species, and in some cases such as the SXT element in Vibrio and the IncJ group element CTnR391, there has been some molecular characterization. The elements thus far examined appear to be larger than the common gram-positive conjugative transposons and to be mosaic in structure, with genes derived from several sources. Recent evidence suggests that in the Enterobacteriaceae the elements may be related to enteric pathogenicity islands. The evolution, distribution and role of these elements in the Enterobacteriaceae is discussed.

Primary hepatic tumours in children: a 26-year review.

Twenty-one children were admitted to a single paediatric institution between 1964-1990 with histologically proven primary liver tumours. The diagnosis was hepatoblastoma (HBL) in 15 patients, hepatocellular carcinoma (HCA) in 2, rhabdomyosarcoma (RMS) in 2, non-Hodgkin's lymphoma (NHL) in 1, and haemangioendothelioma (HE) in 1. The common presenting clinical features were anaemia, abdominal mass, and abdominal pain. Serum alpha-foetoprotein was useful in establishing a diagnosis in HBL and in monitoring disease activity. Computed tomographic (CT) scan, ultrasound, and angiography were useful preoperative investigations for assessing site and resectability of tumour. There were no survivors in patients with malignant hepatic tumours (n = 10) who had surgery alone prior to 1981. Of 7 patients with HBL diagnosed after 1981 who had adequate surgical resection and chemotherapy, 5(72%) are currently alive and disease free between 15 months and 8 years from diagnosis. We conclude that adequate surgical resection and adjuvant chemotherapy can improve disease free survival for children with HBL. Optimal treatment has yet to be devised for other malignant hepatic tumours.