262 research outputs found

    Is Female Health Cyclical? Evolutionary Perspectives on Menstruation

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    Why do some females menstruate at all? Answering this question has implications for understanding the tight links between reproductive function and organismal immunity. Here we build on the growing evidence that menstruation is the by-product of a "choosy" uterus to (i) make the theoretical case for the idea that female immunity is cyclical in menstruating species, (ii) evaluate the evidence for the menstrual modulation of immunity and health in humans and (iii) speculate on the implications of cyclical female health for female behaviour, male immunity and host-pathogen interactions. We argue that an understanding of females' evolved reproductive system is foundational for both tackling the future challenges of the global women's health agenda and predicting eco-evolutionary dynamics in cyclically reproducing species

    The life-history trade-off between fertility and child survival.

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    Evolutionary models of human reproduction argue that variation in fertility can be understood as the local optimization of a life-history trade-off between offspring quantity and 'quality'. Child survival is a fundamental dimension of quality in these models as early-life mortality represents a crucial selective bottleneck in human evolution. This perspective is well-rehearsed, but current literature presents mixed evidence for a trade-off between fertility and child survival, and little empirical ground to evaluate how socioecological and individual characteristics influence the benefits of fertility limitation. By compiling demographic survey data, we demonstrate robust negative relationships between fertility and child survival across 27 sub-Saharan African countries. Our analyses suggest this relationship is primarily accounted for by offspring competition for parental investment, rather than by reverse causal mechanisms. We also find that the trade-off increases in relative magnitude as national mortality declines and maternal somatic (height) and extrasomatic (education) capital increase. This supports the idea that socioeconomic development, and associated reductions in extrinsic child mortality, favour reduced fertility by increasing the relative returns to parental investment. Observed fertility, however, falls considerably short of predicted optima for maximizing total offspring survivorship, strongly suggesting that additional unmeasured costs of reproduction ultimately constrain the evolution of human family size

    Quelles politiques territoriales pour inscrire l’Afrique dans la mondialisation ?

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    Depuis quelques annĂ©es, les infrastructures sont Ă  nouveau reconnues comme un Ă©lĂ©ment fondamental du dĂ©veloppement. En Chine, en Inde, mais Ă©galement en Afrique sub-saharienne, des financements importants sont allouĂ©s Ă  la construction de ponts, de routes, de ports. Plusieurs raisons expliquent cette Ă©volution : rapatriement de capitaux des pays arabes des États-Unis, rĂ©sorption de la dette des pays africains, analyse comparative des expĂ©riences chinoise et indienne.Cet article envisage les articulations possibles entre cette tendance et la mise en oeuvre de politiques d’amĂ©nagement du territoire qui permette d’orienter les choix d’infrastructures vers des stratĂ©gies de dĂ©veloppement. Il montre pourquoi l’Afrique a besoin de politiques d’amĂ©nagement du territoire qui aillent au-delĂ  des Ă©quipements et permettent de faire du territoire un vecteur de dĂ©veloppement. Il prend appui sur une expĂ©rience menĂ©e en Afrique de l’Ouest et du Centre par le Partenariat pour le DĂ©veloppement Municipal, qui tente de renouveler les Ă©chelles, de promouvoir l’intĂ©gration rĂ©gionale, les espaces transfrontaliers et la dĂ©centralisation.Which territorial policies to include Africa in the globalization process? Planning in subsaharian Africa. For a few years, infrastructures are recognized again as a fundamental element of development. In China, in India, but also in sub-Saharan Africa, large funds are allocated to the construction of bridges, roads, ports. This evolution is explained by several reasons: repatriation of Arab countries funds from the United States, absorption of the debt of African countries, cross-analysis of the Chinese and Indian experiences.This article deals with the possible links between this trend and the implementation of regional development policies which make it possible to steer the choices of infrastructures towards development strategies. It shows why Africa needs regional development policies which go beyond public facilities and allows to make of territory a development vector. It is supported on an experience undertaken in Western and Central Africa by the Municipal Development Partnership, which attempts to change the scales, to promote regional integration, cross-border cooperation and decentralization

    The evolutionary ecology of age at natural menopause: implications for public health

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    Evolutionary perspectives on menopause have focused on explaining why early reproductive cessation in females has emerged and why it is rare throughout the animal kingdom, but less attention has been given to exploring patterns of diversity in age at natural menopause. In this paper, we aim to generate new hypotheses for understanding human patterns of diversity in this trait, defined as age at final menstrual period. To do so, we develop a multilevel, interdisciplinary framework, combining proximate, physiological understandings of ovarian ageing with ultimate, evolutionary perspectives on ageing. We begin by reviewing known patterns of diversity in age at natural menopause in humans, and highlight issues in how menopause is currently defined and measured. Second, we consider together ultimate explanations of menopause timing and proximate understandings of ovarian ageing. We find that ovarian ageing is highly constrained by ageing of the follicle – the somatic structure containing the oocyte – suggesting that menopause timing might be best understood as a by-product of ageing rather than a facultative adaptation. Third, we investigate whether the determinants of somatic senescence also underpin menopause timing. We show that diversity in age at menopause can be, at least partly, explained by the genetic, ecological and life-history determinants of somatic ageing. The public health implications of rethinking menopause as the by-product rather than the catalyst of biological ageing are discussed

    The COVID-19 pandemic and the menstrual cycle: research gaps and opportunities

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    International audienceSince the beginning of the COVID-19 pandemic, discussions on social media and blogs have indicated that women have experienced menstrual changes, including altered menstrual duration, frequency, regularity, and volume (heavier bleeding and clotting), increased dysmenorrhea, and worsened premenstrual syndrome. There have been a small number of scientific studies of variable quality reporting on menstrual cycle features during the pandemic, but it is still unclear whether apparent changes are due to COVID-19 infection/illness itself, or other pandemic-related factors like increased psychological stress and changes in health behaviours. It is also unclear to what degree current findings are explained by reporting bias, recall bias, selection bias and confounding factors. Further research is urgently needed. We provide a list of outstanding research questions and potential approaches to address them. Findings can inform policies to mitigate against gender inequalities in health and society, allowing us to build back better post-COVID

    Can pain be self-managed?:Pain change in vulnerable participants to a health education programme

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    Chronic pain exerts a significant impact on the quality of life, giving rise to both physical and psycho-social vulnerabilities. It not only leads to direct costs associated with treatments, but also results in indirect costs due to the reduced productivity of affected individuals. Chronic conditions can be improved by reducing modifiable risk factors. Various educational programs, including the Chronic Disease Self-Management Programme (CDSMP), have demonstrated the advantages of enhancing patient empowerment and health literacy. Nevertheless, their efficacy in addressing pain symptoms has received limited attention, especially concerning vulnerable populations. This research aims to assess the effectiveness of the CDSMP in alleviating pain among socio-economically vulnerable participants with chronic conditions. By accounting for a wide range of variables, and using data from the EFFICHRONIC project (EU health programme), we investigated the changes in pain levels after the intervention, among 1070 participants from five European countries. Our analyses revealed a significant reduction in pain following the intervention. This finding supports the notion that training programs can effectively ameliorate pain and alleviate its impact on the quality of life, particularly in vulnerable populations. Younger participants, as well as those with higher education levels and individuals experiencing higher levels of pain at baseline, were more likely to experience a reduction in their pain levels. These findings underscore the importance of recognising the social determinants of health. The study was registered at ClinicalTrials.gov (ISRCTN70517103).</p

    The hidden benefits of sex: Evidence for MHC-associated mate choice in primate societies

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    Major histocompatibility complex (MHC)-associated mate choice is thought to give offspring a fitness advantage through disease resistance. Primates offer a unique opportunity to understand MHC-associated mate choice within our own zoological order, while their social diversity provides an exceptional setting to examine the genetic determinants and consequences of mate choice in animal societies. Although mate choice is constrained by social context, increasing evidence shows that MHC-dependent mate choice occurs across the order in a variety of socio-sexual systems and favours mates with dissimilar, diverse or specific genotypes non-exclusively. Recent research has also identified phenotypic indicators of MHC quality. Moreover, novel findings rehabilitate the importance of olfactory cues in signalling MHC genes and influencing primate mating decisions. These findings underline the importance to females of selecting a sexual partner of high genetic quality, as well as the generality of the role of MHC genes in sexual selection

    Kin recognition signals in adult faces

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    Maloney and Dal Martello&nbsp;reported that similarity ratings of pairs of related and unrelated children were almost perfect predictors of the probability that those children were judged as being siblings by a second group of observers. Surprisingly, similarity ratings were poor predictors of whether a pair was same-sex or opposite- sex, suggesting that people ignore cues that are uninformative about kinship when making similarity judgments of faces. Using adult sibling faces, we find that similarity ratings for same-sex pairs were significantly higher than for opposite-sex pairs, suggesting that similarity judgments of adult faces are not entirely synonymous with kinship judgments
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