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February 2010 (82:1) Forthcoming |
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Table of Contents |
MORTALITY VARIATION BY BIRTH REGION AND ETHNICITY: AN ILLUSTRATION BASED ON THE FINNISH POPULATION REGISTER
Jan Saarela & Fjalar Finnäs
Abstract |
Previous research says that the persistent regional mortality differences in Finland cannot be attributed to socio-demographic factors, health behaviours, or living conditions at young age. Using longitudinal population register data from Finland, we analyse the effect of birth region and ethnicity on mortality risks in men aged 65-74 years and women aged 75-84 years. Mortality from ischemic heart disease in particular is found to be highly influenced by these proxies for people’s ancestry. The results are consistent with findings from population genetic and medical research, which say that there is great genetic diversity across major regions in the country and that this diversity may underlie variation in disease susceptibility. We argue that the regional mortality variation might reflect geographic clustering of hereditary factors, enforced by Finland’s specific population development. The paper illustrates that large-scale population register data without genetic information or biomarkers can be useful for understanding cause-specific mortality within a national population. |
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Can life history trade-offs explain the evolution of short stature in human pygmies? A response to Migliano and colleagues (2007) |
Noémie SA Becker, Paul Verdu, Barry Hewlett and Samuel Pavard |
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Abstract |
Walker et al. (2006) used life-history theory to develop an innovative explanation for human diversity in stature. Short stature could have been selected for in some human populations due to the advantage of an earlier growth cessation and earlier reproduction in a context of high mortality. Migliano et al. (2007) recently published an important article that tested this hypothesis to explain short stature in human pygmy populations. However innovative this work may be, we felt that some data and results presented herein were controversial if not questionable. As problematic points we note 1) the use of an arbitrary threshold of height (155cm) to categorize populations into pygmies and non-pygmies; 2) the use of demographic data from Philippine pygmy groups that have experienced dramatic cultural and environmental changes in the last 20 years and 3) the use of demographic data concerning African pygmy groups since good systematic data on these groups is not available. Finally we report here mathematical errors and loopholes in the optimisation model developed by the authors. In this paper we suggest alternative trade-offs that can be used to explain the authors’ results on more reliable bases. |
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Linear Measurements of the Neurocranium Are Better Indicators of Population Differences than Those of the Facial Skeleton: A Comparative Study of 1961 Skulls |
Gábor Holló, László Szathmáry, Antónia Marcsik, and Zoltán Barta |
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Abstract |
The aim of the study was to individualize potential differences between two cranial regions in differentiating human populations. The neurocranium and the facial skeleton were compared to each other. Skulls from the Great Hungarian Plain were examined. They are dated back to the 1st – 11th centuries, a long space of time that encompasses seven archaeological periods. We analyzed six neurocranial and seven facial measurements. The reduction of the number of variables was carried out by Principal Components Analysis. Linear mixed-effects models (LMM) were fit to the principal components of each archaeological period, and then the models were compared by multiple pairwise tests. The neurocranium showed significant differences in seven cases between non-subsequent periods, and, in one case, between two subsequent populations. In the case of the facial skeleton, no significant results were found. Our results, which are also compared to previous craniofacial heritability estimates, suggest that the neurocranium is a more conservative region, and population differences can be pointed out better by the neurocranium than by the facial skeleton. |
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A Model of the Mechanisms of Language Extinction, and Revitalization Strategies to Save Endangered Languages.
Chrisantha Fernando, Riitta-Liisa Valijärvi, Richard A. Goldstein
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Why and how have languages died out? A mathematical model is devised to help understand how languages go extinct. We use the model to ask whether language extinction could be prevented in future, and why it may have occurred in the past. Despite a growing number of mathematical models of language dynamics that study the conditions for language co-existence and death, their phenomenological approach compromises their ability to influence language revitalization policy. In contrast, here we model the mechanisms underlying language competition and how these are influenced by specific language revitalization interventions, namely private interventions to raise the status of the language and thus promote language learning at home, public interventions to increase the use of the minority language, and explicit teaching of the minority language in schools. Our model reveals that it is possible to preserve a minority language, but that continued long-term interventions are likely to be necessary. We identify the parameters that determine which interventions work best under certain linguistic and societal circumstances. In this way the efficacy of interventions of various types can be identified and predicted. Although there are qualitative arguments for these parameter values (e.g. the responsiveness of children to learning a language as a function of the proportion of conversations heard in that language, the relative importance of conversations heard in the family and elsewhere, and the amplification of spoken to heard conversations of the high-status language due to media), extensive quantitative data are lacking in this field. We propose how these parameters could be measured, allowing our model, as well as others models in the field, to be validated. |
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Raymond Pearl and the Shaping of Human Biology
Michael A. Little and Ralph M. Garruto
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Raymond Pearl (1879-1940) was a significant figure in the field of biology. He founded the journal Human Biology and almost single handedly promoted and established the scientific discipline of human biology. His scientific versatility was one of his most important features during the first four decades of the 20th century, and he played a major role in developing the fields of biodemography, human population biology, human life-cycle and lifespan approaches, fertility, growth, the biology of longevity and senescence, and mortality. He was one of the earliest biologists to combine biometrical analyses and experimental studies to explore the dimensions of human biology. Pearl also was noted as a man who was broadly educated in the arts, music, literature, history, the classics, and science. His writing was sophisticated and often witty, and his views were sometimes provocative and controversial. His network of colleagues and friends among the literary and science worlds was substantial. The following biographical memoir of Raymond Pearl is designed to commemorate the 80th anniversary of the founding of his journal, Human Biology, and is a tribute to this great scientist. Pearl’s sudden death at age 61 years, truncated a scientific career that was one on the most productive of the 20th century. |
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Short Communication
Maternal preconception diet and the sex ratio
J.S. Cramer and L.H. Lumey
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Temporal variations in the sex ratio or the ratio of boys over girls at birth have been widely studied and variously attributed to social changes, conditions of war, and environmental changes. Recently, Mathews, Johnson and Neil (2008) studied the direct evidence of individual pregnancies and established an association between the sex at birth and the mother’s preconception diet. We examined the hypothesis using new evidence from the wartime famine in Holland in 1944/45 and failed to show an association between maternal diet in pregnancy and the sex ratio. This makes a causal link highly improbable. [...] |
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Letter to the Editor
Why are pygmies so short? A defence of Migliano’s hypothesis |
Andrea Bamberg Migliano, Lucio Vinicius and Marta Mirazón Lahr |
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Dear Editor, Migliano has formulated and tested in her three publications (Migliano 2005, Walker et al. 2006, Migliano et al. 2007) a hypothesis explaining pygmy size as the result of a ‘fast’ life history strategy (Charnov 1993) in which early start of reproduction and growth termination are adaptive responses to high external mortality rates. We thank Becker et al. (this issue) for the careful analysis of our work and the editor for the opportunity to clarify the points made in their commentary. Their criticisms are in part related to a regrettable typo in a figure that we did not see at the page proof stage; the other points do not seriously challenge our hypothesis as discussed below. [...] |
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Book Review
Negotiating Risk: British Pakistani Experiences of Genetics |
Natasha Arora |
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