Impact of selection and demography on the diffusion of lactase persistence.

The lactase enzyme allows lactose digestion in fresh milk. Its activity strongly decreases after the weaning phase in most humans, but persists at a high frequency in Europe and some nomadic populations. Two hypotheses are usually proposed to explain the particular distribution of the lactase persistence phenotype. The gene-culture coevolution hypothesis supposes a nutritional advantage of lactose digestion in pastoral populations. The calcium assimilation hypothesis suggests that carriers of the lactase persistence allele(s) (LCT*P) are favoured in high-latitude regions, where sunshine is insufficient to allow accurate vitamin-D synthesis. In this work, we test the validity of these two hypotheses on a large worldwide dataset of lactase persistence frequencies by using several complementary approaches. Methodology We first analyse the distribution of lactase persistence in various continents in relation to geographic variation, pastoralism levels, and the genetic patterns observed for other independent polymorphisms. Then we use computer simulations and a large database of archaeological dates for the introduction of domestication to explore the evolution of these frequencies in Europe according to different demographic scenarios and selection intensities. Conclusions Our results show that gene-culture coevolution is a likely hypothesis in Africa as high LCT*P frequencies are preferentially found in pastoral populations. In Europe, we show that population history played an important role in the diffusion of lactase persistence over the continent. Moreover, selection pressure on lactase persistence has been very high in the North-western part of the continent, by contrast to the South-eastern part where genetic drift alone can explain the observed frequencies. This selection pressure increasing with latitude is highly compatible with the calcium assimilation hypothesis while the gene-culture coevolution hypothesis cannot be ruled out if a positively selected lactase gene was carried at the front of the expansion wave during the Neolithic transition in Europe.

Future trends in cystic fibrosis demography in 34 European countries

<p>Median survival has increased in people with cystic fibrosis (CF) during the past six decades, which has led to an increased number of adults with CF. The future impact of changes in CF demographics has not been evaluated. The aim of this study was to estimate the number of children and adults with CF in 34 European countries by 2025. Data were obtained from the European Cystic Fibrosis Society Patient Registry. Population forecasts were performed for countries that have extensive CF population coverage and at least 4���years of longitudinal data by modelling future entering and exiting flows in registry cohorts. For the other countries, population projections were performed based on assumptions from knowledge of current CF epidemiology. Western European countries' forecasts indicate that an increase in the overall number of CF patients by 2025, by approximately 50%, corresponds to an increase by 20% and by 75% in children and adults, respectively. In Eastern European countries the projections suggest a predominant increase in the CF child population, although the CF adult population would also increase.It was concluded that a large increase in the adult CF population is expected in the next decade. A significant increase in adult CF services throughout Europe is urgently required.</p>

Quantification of key biological processes determining the dynamics and the assessment of the anchovy population in the Bay of Biscay: growth, reproduction, demography and natural mortality.

333 p.

Demography of a deep-sea lantern shark (Etmopterus spinax) caught in trawl fisheries of the northeastern Atlantic: Application of Leslie matrices with incorporated uncertainties

The deep-sea lantern shark Etmopterus spinax occurs in the northeast Atlantic on or near the bottoms of the outer continental shelves and slopes, and is regularly captured as bycatch in deep-water commercial fisheries. Given the lack of knowledge on the impacts of fisheries on this species, a demographic analysis using age-based Leslie matrices was carried out. Given the uncertainties in the mortality estimates and in the available life history parameters, several different scenarios, some incorporating stochasticity in the life history parameters (using Monte Carlo simulation), were analyzed. If only natural mortality were considered, even after introducing uncertainties in all parameters, the estimated population growth rate (A) suggested an increasing population. However, if fishing mortality from trawl fisheries is considered, the estimates of A either indicated increasing or declining populations. In these latter cases, the uncertainties in the species reproductive cycle seemed to be particularly relevant, as a 2-year reproductive cycle indicated a stable population, while a longer (3-year cycle) indicated a declining population. The estimated matrix elasticities were in general higher for the survivorship parameters of the younger age classes and tended to decrease for the older ages. This highlights the susceptibility of this deep-sea squaloid to increasing fishing mortality, emphasizing that even though this is a small-sized species, it shows population dynamics patterns more typical of the larger-sized and in general more vulnerable species. (C) 2014 Elsevier Ltd. All rights reserved.

Crossing frontiers between tourism and demography. An empirical analysis based on European travellers��� behaviour

This paper aims to establish possible tourism demand scenarios of European travellers to Portugal based on the relationship with changing population structures. A combination of the EuROBAROMETER report 370 (���Attitudes of Europeans towards Tourism in 2013���) and the cohort-component method for population projections will allow the development of different possible tourism demand scenarios. Following the European report, individuals who travelled in 2013 were most likely to live in a household with two or more individuals. Thus, if elderly couples are together till later in their life and in better physiological shape, it is possible that the number of elderly individuals travelling for tourism purposes will increase in the near future. If we can expect tourists from developing countries to be younger due to their demographic dynamics than those from developed countries, where the ageing population is growing fast, we can expect that the percentage of the elderly among tourists will increase. Furthermore, the 2013 European report found that the combination of socio-demographic variables, such as, age, population, gender, household dimension, country of residence and trip purpose explained tourism demand scenarios for Portugal, confirming that seniors and families evidence a paramount sense of importance for the destination. In the literature there is a lack of discussion about the effects of demography in the future and the role of an ageing population in tourism demand choice patterns. We aim to contribute to filling this gap. Consequently, we strongly believe that this paper contributes to the literature by introducing a new field of discussion about the importance of demographic changes in shaping travel trends.

Crossing frontiers between tourism and demography. An empirical analysis based on European travellers��� behaviour

This paper aims to establish possible tourism demand scenarios of European travellers to Portugal based on the relationship with changing population structures. A combination of the EUROBAROMETER report 370 (���Attitudes of Europeans towards Tourism in 2013���) and the cohort-component method for population projections will allow the development of different possible tourism demand scenarios. Following the European report, individuals who travelled in 2013 were most likely to live in a household with two or more individuals. Thus, if elderly couples are together till later in their life and in better physiological shape, it is possible that the number of elderly individuals travelling for tourism purposes will increase in the near future. If we can expect tourists from developing countries to be younger due to their demographic dynamics than those from developed countries, where the ageing population is growing fast, we can expect that the percentage of the elderly among tourists will increase. Furthermore, the 2013 European report found that the combination of socio-demographic variables, such as, age, population, gender, household dimension, country of residence and trip purpose explained tourism demand scenarios for Portugal, confirming that seniors and families evidence a paramount sense of importance for the destination. In the literature there is a lack of discussion about the effects of demography in the future and the role of an ageing population in tourism demand choice patterns. We aim to contribute to filling this gap. Consequently, we strongly believe that this paper contributes to the literature by introducing a new field of discussion about the importance of demographic changes in shaping travel trends.

Health-related And Socio-demographic Factors Associated With Frailty In The Elderly: A Systematic Literature Review.

Frailty is a syndrome that leads to practical harm in the lives of elders, since it is related to increased risk of dependency, falls, hospitalization, institutionalization, and death. The objective of this systematic review was to identify the socio-demographic, psycho-behavioral, health-related, nutritional, and lifestyle factors associated with frailty in the elderly. A total of 4,183 studies published from 2001 to 2013 were detected in the databases, and 182 complete articles were selected. After a comprehensive reading and application of selection criteria, 35 eligible articles remained for analysis. The main factors associated with frailty were: age, female gender, black race/color, schooling, income, cardiovascular diseases, number of comorbidities/diseases, functional incapacity, poor self-rated health, depressive symptoms, cognitive function, body mass index, smoking, and alcohol use. Knowledge of the complexity of determinants of frailty can assist the formulation of measures for prevention and early intervention, thereby contributing to better quality of life for the elderly.

A casa e a ro��a: socioeconomia, demografia e agricultura em popula����es quilombolas do Vale do Ribeira, S��o Paulo, Brasil

Este estudo tem como objetivos caracterizar o perfil demogr��fico e socioecon��mico de nove comunidades remanescentes de quilombos no vale do Ribeira, estado de S��o Paulo, e identificar os principais fatores respons��veis pelas mudan��as recentes nos seus padr��es de subsist��ncia. Desde a forma����o das primeiras aglomera����es de escravos libertos e foragidos no s��culo XVIII, as rela����es estabelecidas entre estas popula����es com as cidades pr��ximas e com o mercado regional t��m vivenciado momentos de retra����o e de expans��o, adaptando-se e ajustando-se a novas mudan��as pol��ticas e socioecon��micas. Nas ��ltimas cinco d��cadas, o impacto de fatores externos na acelera����o das mudan��as nos padr��es de subsist��ncia locais parece ter tido um aumento significativo. Os resultados mostram que as restri����es impostas pela legisla����o ambiental, os conflitos de terra, a constru����o de uma rodovia na regi��o, a crescente inser����o no mercado regional e a atua����o de ��rg��os governamentais e n��o-governamentais de desenvolvimento s��o os principais fatores respons��veis pelas mudan��as observadas no sistema agr��cola de corte e queima e, conseq��entemente, na organiza����o socioecon��mica destas popula����es.

Qualidade de vida e fatores associados em idosos dependentes em uma cidade do interior do Nordeste

OBJETIVO: Este estudo tem por objetivo verificar a influ��ncia de fatores sociodemogr��ficos, condi����es de sa��de, capacidade funcional e din��mica familiar na qualidade de vida de idosos dependentes residentes em domic��lio em uma cidade do interior da regi��o do Nordeste. M��TODOS: Trata-se de uma pesquisa de car��ter anal��tico com delineamento transversal. A amostra deste estudo foi composta por 117 idosos dependentes, cadastrados nas Unidades de Sa��de da Fam��lia da ��rea de abrang��ncia do bairro do Jequiezinho, no munic��pio de Jequi��, BA. Os instrumentos de coleta de dados utilizados foram o WHOQOL-OLD, o ��ndice de Barthel, o Apgar de Fam��lia e o levantamento de dados sociodemogr��ficos e condi����es de sa��de. RESULTADOS: Com a aplica����o do Teste do qui-quadrado (x��) encontrou-se diferen��a estat��stica entre comprometimento da qualidade de vida e da din��mica familiar, com exce����o do dom��nio autonomia (p = 0,061) da qualidade de vida. CONCLUS��ES: Apenas o comprometimento da din��mica familiar influencia de maneira negativa a qualidade de vida dos idosos dependentes, uma vez que, quanto mais prejudicada a funcionalidade familiar, pior a qualidade de vida desses.

Working at night and work ability among nursing personnel: when precarious employment makes the diVerence

Purpose To test the association between night work and work ability, and verify whether the type of contractual employment has any inXuence over this association. Methods Permanent workers (N = 642) and workers with precarious jobs (temporary contract or outsourced; N = 552) were interviewed and Wlled out questionnaires concerning work hours and work ability index. They were classiWed into: never worked at night, ex-night workers, currently working up to Wve nights, and currently working at least six nights/2-week span. Results After adjusting for socio-demography and work variables, current night work was signiWcantly associated with inadequate WAI (vs. day work with no experience in night work) only for precarious workers (OR 2.00, CI 1.01- 3.95 and OR 1.85, CI 1.09-3.13 for those working up to Wve nights and those working at least six nights in 2 weeks, respectively). Conclusions Unequal opportunities at work and little experience in night work among precarious workers may explain their higher susceptibility to night work

Diferenciais de c��rie dent��ria entre os ��ndios Xavante de Mato Grosso, Brasil

O objetivo do estudo foi avaliar n��veis de experi��ncia de c��rie entre subgrupos Xavante que vivem em diferentes Terras Ind��genas (T.I.) no Estado de Mato Grosso, Brasil, a fim de investigar a presen��a de desigualdades no interior de uma mesma etnia ind��gena. Os dados foram coletados atrav��s de um censo de sa��de bucal realizados em 2004. Das sete T.I. Xavante existentes, foram investigadas quatro (Pimentel Barbosa, Sangradouro, Are��es e Marechal Rondon), nas quais foram selecionadas a maior aldeia de cada. Foram adotados os crit��rios preconizados pela Organiza����o Mundial da Sa��de, e utilizado o ��ndice CPOS. Para mensurar as diferen��as entre as T.I. foi estimada a raz��o de preval��ncia (RP) por meio de an��lise de regress��o de Poisson, efetuada na faixa et��ria entre 6 e 34 anos para cada sexo, incluindo a idade como covari��vel. Nesta faixa et��ria, as perdas variaram entre 26 a 30 por cento. Pimentel Barbosa foi considerada como refer��ncia para compara����es por apresentar menor preval��ncia de c��rie em todas as faixas et��rias analisadas. A maior disparidade foi notada entre as T.I. Pimentel Barbosa e Sangradouro, tanto em homens (RP 2,68- IC95 por cento 2,41 a 2,97) como em mulheres (RP 2,03- IC95 por cento 1,85 a 2,23). A RP do componente obturado em Are��es e Marechal Rondon (diferen��a relativa a Pimentel Barbosa) �� muito pequena em rela����o �� carga de doen��a total nestas T.I., indicando menor presen��a de servi��o odontol��gico restaurador. Conclui-se que a transi����o em sa��de bucal n��o �� homog��nea entre os Xavante e que as diferen��as podem estar associadas a particularidades do processo hist��rico de intera����o com a sociedade n��o-ind��gena (Continua) (Continua����o) Determinantes locais e regionais, incluindo fatores demogr��ficos, caracter��sticas econ��micas e s��cio-culturais espec��ficas, acesso e utiliza����o de servi��os de sa��de, podem ter determinado as desigualdades de ataque de c��rie observadas entre os Xavante

CONTRASTING PHYLOGEOGRAPHIC PATTERNS IN MITOCHONDRIAL DNA AND MICROSATELLITES: EVIDENCE OF FEMALE PHILOPATRY AND MALE-BIASED GENE FLOW AMONG REGIONAL POPULATIONS OF THE BLUE-AND-YELLOW MACAW (PSITTACIFORMES: ARA ARARAUNA) IN BRAZIL

Comparing the patterns of population differentiation among genetic markers with different modes of inheritance call provide insights into patterns of sex-biased dispersal and gene flow. The blue-and-yellow Macaw (Ara ararauna) is a Neotropical parrot with a broad geographic distribution ill South America. However, little is known about the natural history and current status Of remaining wild populations, including levels of genetic variability. The progressive decline and possible fragmentation of populations may endanger this species in the near future. We analyzed mitochondrial DNA (mtDNA) control-region sequences and six microsatellite 106 Of Blue-and-yellow Macaws sampled throughout their geographic range ill Brazil to describe population genetic Structure, to make inferences about historical demography and dispersal behavior, and to provide insight for conservation efforts. Analyses of population genetic structure based on mtDNA showed evidence of two major populations ill western and eastern Brazil that share a few low-frequency haplotypes. This phylogeographic pattern seems to have originated by the historical isolation of Blue-and-yellow Macaw populations similar to 374,000 years ago and has been maintained by restricted gene flow and female philopatry. By contrast, variation ill biparentally inherited microsatellites was not structured geographically, Male-biased dispersal and female philopatry best explain the different patterns observed in these two markers. Because females disperse less than males, the two regional populations with well-differentiated mtDNA haplogroups should be considered two different management units for conservation purposes. Received 4 November 2007 accepted 10 December 2008.

Shedding light on technological development in Brazil

We try to shed some light oil the question of wily technology-intensive businesses often fail in less-developed countries and under what circumstances they are likely to be a Success from the perspective of both domestic and export markets. The answers were drawn from a set of empirical evidences from Brazilian firms applying photonics technologies. Sonic of the issues faced by them are related to the question of state versus private initiative, entering traditional versus niche market, and technology transfer versus product development management. In overall, we concluded that weakness of the institutions and inadequacy of social and organizational demography play a key role in explaining to a large extent wily countries differ in technological development and diffusion. In this context, we point out obstacles, which must be removed in order to make public policies and firm`s achievements more efficient. (C) 2008 Elsevier Ltd. All rights reserved.

Tillering dynamics in palisadegrass swards continuously stocked by cattle

Plant communities on pastures adapt to varying frequencies and severities of defoliation through mechanisms capable of ensuring their longevity and photosynthetic efficiency. The objective of this experiment was to evaluate tiller population density, demographic patterns of tillering and population stability of palisadegrass swards subjected to four grazing intensities. Treatments corresponded to four sward steady state conditions (sward heights of 10, 20, 30 and 40 cm) generated by continuous stocking. Measurements of tiller population density and population dynamics were performed at 4 week intervals and the results were used to calculate tiller appearance, death and survival rates. Tiller appearance and death rate were used to calculate sward stability index. The results indicate that keeping swards low (10 cm or lower) may be prejudicial to persistency and productivity of palisadegrass. The results also indicate that a low tiller population alone should not be considered as an indicator of loss of productive potential and of reduced plant persistency, since swards may be stable even with low population of tillers.