Biomedical subjects

J P Bocquet-Appel

Publications and source records attributed to J P Bocquet-Appel.

5 recordsLinked to original sources

PubMed1997

Brief communication: estimates of some demographic parameters in a Neolithic rock-cut chamber (approximately 2000 BC) using iterative techniques for aging and demographic estimators.

Two new techniques-one anthropological, which estimates the mean age at death for adult skeletons, the other demographic, which gives main survivorship curve parameters-are used on a sample of skeletons (N approximately 170) discovered in a Neolithic rock-cut chamber (Loisy-en-Brie, France). The iterative technique for aging used a stochastic sampled F matrix derived from the trabecular involution of the femoral head observed in the reference collection of Coimbra (Portugal; N = 421). The results, obtained from techniques and data, independent of each other, are strongly consistent. Overall, they give a life expectancy at birth of about 25-28 years and the probability of death at 1 and 5 years, respectively, of about .271-.249 and .429-.380.

Adolescent↗

PubMed1996

Paleodemography: expectancy and false hope.

From parent populations (N = 50,000) stochastically generated, representing different levels of correlation (r) between the age at death and a hypothetical biological indicator (r = 0.8-0.98), reference samples and target demographic samples are randomly drawn. Two iterative techniques, proportional fitting procedure and Bayesian, are used to estimate from the reference samples the age distribution of the targets. Due to the random fluctuations of the pattern of aging, both in the reference and target samples, these techniques converge only in expectation toward the true value of a distribution, but not in practice for any particular realization. Nevertheless, these techniques allow the estimation of the average of an age distribution, even if its shape is unknown. Under the hypothesis that the target sample is drawn from a stationary population, this average represents the life expectancy at 20 years (plus 20 years). Using this mean age at death for the adults and the juvenility index at death (D5-14/D20-omega), a new set of paleodemographic estimators were derived from 40 archaic life tables. For a hypothesized stable population, they give the life expectancy at birth and at 20 years, and the probability of death at 1 and 5 years.

Adult↗

PubMed1993

Isolation by distance, trend surface analysis, and spatial autocorrelation.

The isolation by distance model is both a population process and a surface model. In this model the surface is, on average, flat in every direction. By contrast, probably most observed genetic surfaces exhibit trends generated by complex long-distance populational processes. When one estimates the parameters of a Malécot-Morton equation for those surfaces, the isolation by distance model does not fit. In the simplest case, in first-order trends (two-dimensional clines) the genetic differentiation increases dramatically, faster per unit distance than it would by isolation by distance alone. When isolation by distance takes place but is hidden through the apparent and complicated relief of a surface, another surface model incorporating trend spatial analysis can bypass the difficulty of estimating the isolation by distance process if approached through the Malécot-Morton equation or through a measure of spatial autocorrelation.

ABO Blood-Group System↗

PubMedDate not supplied

Familial transmission of longevity.

The Tau model of phenotypic transmission has been used to analyze the familial correlations (nuclear families and extended families) of longevity at Arthez d'Asson (individuals born between 1686 and 1899). At birth, the transmissibility (t2) is very weak: 0.103; at 20 years old, t2 = 0.167; at 50 years old, t2 = 0.294. The effect of sibling environment on children's phenotype is s = 0.086 at birth, is thus null. A cohabitional effect between spouses: p = 0.167 appears after 50 years. There is no social homogamy effect via grandparents.

Adult↗

PubMedDate not supplied

A test of a path model of biocultural transmission of fertility.

A model adapted to a general linear model of phenotypic transmission (two components: (1) genetic additive, (2) cultural [age at marriage]) has been used to analyse the familial correlations of fertility (number of children) born before the demographic transition at Arthez d'Asson (Béarn, 1744-1889). The model is rejected: chi 2 = 55.7 with 6d.f. In the ancient demographical regime, reproduction and nuptiality of a couple were not influenced by their parents but by their generation.

Culture↗