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Biomedical subjects

R J Walsh

Publications and source records attributed to R J Walsh.

72 records · Page 4Linked to original sources
PubMedDate not supplied

Pitcairn Island: fertility and population growth, 1790-1856.

The hybrid English-Tahitian community which lived on Pitcairn Island between 1790 and 1856 exhibited a high population growth (3% overall). Unlike some other isolated groups, they did not live long lives (expectation of life at birth was 50.4 years overall for both sexes combined), but infant mortality, at 5.5% of births is lower than might have been expected. The level of marital fertility on Pitcairn was extremely high, higher even than for the Hutterites. Although births outside marriage were uncommon, brides were frequently pregnant at marriage. Age at first marriage changed markedly in response to changes in the community. There is some evidence that premarital sex became more frequent, possibly as an adjustment to Tahitian behavioural norms within the community's English religious ethic.

Adolescent↗
PubMedDate not supplied

A twin study of skin reflectance.

Skin colour has been measured by reflectance spectrophotometry on 134 pairs of twins at three sites, forehead, forearm and upper arm, each at three wavelengths, 425, 545 and 685 nm. Tanning is measured most reliably at 685 nm and at this wavelength the heritability is high at the least exposed upper arm site, intermediate on the forearm, while on the forehead variation is entirely environmentally determined. The same gradient is observed, through less strikingly at 545 nm, but at 425 nm, where haemoglobin is reflecting most of the light, the degree of genetic determination is the same at all sites.

Adolescent↗