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1.
There has been considerable speculation about the adaptive significance of the human female orgasm, with one hypothesis being that it promotes differential affiliation or conception with high-quality males. We investigated the relationship between women's self-reported orgasm frequency and the characteristics of their partners in a large representative sample from the Chinese Health and Family Life Survey. We found that women report more frequent orgasms the higher their partner's income is. This result cannot be explained by possible confounds such as women's age, health, happiness, educational attainment, relationship duration, wealth difference between the partners, difference between the partners in educational attainment, and regional location. It appears consistent with the view that female orgasm has an evolved adaptive function.  相似文献   

2.
This paper analyzes the influence of the nutritional status of resources on the adaptive response to interspecific competition in a consumer of those resources. The two cases compared are that in which the resources are nutritionally perfectly substitutable (in the sense of Leon and Tumpson [1975]) and that in which the resources are nonsubstitutable. Each nonsubstitutable resource must be consumed at a certain rate for population growth to occur. Evolutionarily stable strategies of resource utilization are found using models of competition for two resources. If competition occurs solely via the consumer species's effects on resource density, the adaptive response in a consumer's resource-acquisition traits is: a) divergence away from its competitor's resource-acquisition traits if resources are perfectly substitutable and b) convergence towards the competitor's resource-acquisition traits if resources are nonsubstitutable. Exceptions to both of these generalizations may occur if competitor population density affects a consumer species's per capita growth rate independently of effects on resource density. Plants and herbivores often use nonsubstitutable resources. The lack of studies of adaptive responses to competition in these organisms may be responsible for the lack of documented examples of competitive convergence.  相似文献   

3.
One of the great underlying assumptions made by all scientists utilizing primate models for their research is that the optimal nutritional status and health of the animals in use has been achieved. That is, no nutrient deficiency or excess has compromised their health in any detectable way. To meet this assumption, we rely on the National Research Council's (NRC's) nutritional recommendations for nonhuman primates to provide accurate guidance for proper dietary formulations. We also rely on feed manufacturers to follow these guidelines. With that in mind, the purpose of this commentary is to discuss three related points that we believe have significant ramifications for the health and well being of captive primates as well as for their effective use in biomedical research. First, our laboratory has shown that most experimental primates are likely in a state of hypervitaminosis A. Second, it is apparent that many primate diets are providing vitamin A at levels higher than the NRC's recommendation. Third, the recommendation itself is based on inadequate information about nutrient needs and is likely too high, especially when compared with human requirements. Am. J. Primatol. 71:813–816, 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

4.
Women experience significant changes in iron status throughout their reproductive lifespans. While this is evident in regions with high rates of malnutrition and infectious disease, the extent of reproductive-related changes is less well known in countries with low rates of iron deficiency anemia, such as the United States. The goal of this study is determine the relationship between women''s reproductive variables (pregnancy, parity, currently breastfeeding, regular menstruation, hormonal contraceptive use, and age at menarche) and iron status (hemoglobin, ferritin, transferrin receptor, and % transferrin saturation) using an anthropological framework for interpreting the results. Data from women aged 18–49 were taken from the 1999–2006 US NHANES, a nationally representative cross-sectional sample of US women. Using multiple imputation and complex survey statistics, women''s reproductive variables were regressed against indicators of iron status. Pregnant women had significantly poorer iron status, by most indicators, than non-pregnant women. All biomarkers demonstrated significantly lower iron levels with increasing parity. Women who were having regular periods had iron indicators that suggested decreased iron levels, while women who used hormonal contraceptives had iron indicators that suggested increased iron levels. Despite relatively good iron status and widespread availability of iron-rich foods in the US, women still exhibit patterns of iron depletion across several reproductive variables of interest. These results contribute to an ecological approach to iron status that seeks to understand variation in iron status, with the hopes that appropriate, population-specific recommendations can be developed to improve women''s health.  相似文献   

5.
Life history theory views reproduction as an outcome of resource allocation. The allocation of resources such as parental investments of time, energy and material resources involves trade-offs between number of offspring and timing of reproduction. Within the framework of mammalian parental investment, the outstanding feature of human reproduction is the high level of paternal care. Although empirical evidence suggests that human paternal investment may have evolved as a reproductive strategy to reduce infant and child mortality rates, the effects of actual paternal investment, including allocating time to child care, on female reproductive decisions have received relatively little attention. We examined the trade-off from two perspectives using a representative sample of married South Korean women aged 20–44 in 2005 (n=977). First, paternal investment in domestic labor, including child care and housework, was expected to be associated with women's preference regarding future reproduction. Second, relative paternal investment was expected to increase women's preference for future reproduction, especially among employed women. We found that increased paternal investment in child care and housework remarkably enhanced women's intention to have a second child, especially among employed women. In addition, although family members provide a low percentage of child care in South Korea, such help is likely to be a useful resource for second childbirth among employed women. Somewhat expectedly, older age and longer time since first birth had negative effects on women's second-child intention. There is growing evidence that, in the lowest fertility societies, paternal investment may be an essential resource for promoting future reproductive behavior of women, especially employed women.  相似文献   

6.
Researchers studying human sexuality have repeatedly concluded that men place more emphasis on the physical attractiveness of potential mates than women do, particularly in long-term sexual relationships. Evolutionary theorists have suggested that this is the case because male mate value (the total value of the characteristics that an individual possesses in terms of the potential contribution to his or her mate’s reproductive success) is better predicted by social status and economic resources, whereas women’s mate value hinges on signals conveyed by their physical appearance. This pattern may imply that women trade off attractiveness for resources in mate choice. Here I test whether a trade-off between resources and attractiveness seems to be occurring in the mate choice decisions of women in the United States. In addition, the possibility that the risk of mate desertion drives women to choose less attractive men as long-term mates is tested. The results were that women rated physically attractive men as more likely to cheat or desert a long-term relationship, whereas men did not consider attractive women to be more likely to cheat. However, women showed no aversion to the idea of forming long-term relationships with attractive men. Evidence for a trade-off between resources and attractiveness was found for women, who traded off attractiveness, but not other traits, for resources. The potential meaning of these findings, as well as how they relate to broader issues in the study of sex differences in the evolution of human mate choice for physical traits, is discussed.  相似文献   

7.
Low male voice pitch may communicate potential benefits for offspring in the form of heritable health and/or dominance, whereas access to resources may be indicated by correlates of socioeconomic status, such as sociolinguistic features. Here, we examine if voice pitch and social dialect influence women's perceptions of men's socioeconomic status and attractiveness. In Study 1, women perceived lower pitched male voices as higher in socioeconomic status than higher pitched male voices. In Study 2, women independently perceived lower pitched voices and higher status sociolinguistic dialects as higher in socioeconomic status and attractiveness. We also found a significant interaction wherein women preferred lower pitched men's voices more often when dialects were lower in sociolinguistic status than when they were higher in sociolinguistic status. Women also perceived lower pitched voices as higher in socioeconomic status more often when dialects were higher in sociolinguistic status than when lower in sociolinguistic status. Finally, women's own self-rated socioeconomic status was positively related to their preferences for voices with higher status sociolinguistic dialects, but not to their preferences for voice pitch. Hence, women's preferences for traits associated with potentially biologically heritable benefits, such as low voice pitch, are moderated by the presence of traits associated with resource accrual, such as social dialect markers. However, women's preferences for language markers of resource accrual may be functionally independent from preferences for potential biological indicators of heritable benefits, such as voice pitch.  相似文献   

8.
This article investigates some aspects of the shape of the functional responses of consumers that utilize two resources. Adaptive variation in consumption behavior is shown to have a major effect on the relationship between amount of resource available and its rate of consumption by an average consumer individual. The effects of adaptive variation are dependent on the nutritional status of the two resources. If the resources are linearly substitutable, increases in the density of resource i will usually increase the quantity, functional response on i divided by density of i, and increases in the density of resource j will decrease this quantity. The result is that the functional response to resource i will generally decrease with the density of resource j, and will increase faster than it would otherwise have increased with the density of resource i. If resources are nonsubstitutable, an adaptive functional response to resource i will increase with the density of resource j, and it will increase more slowly with the density of resource i than it would have without adaptive change. If resources are both complementary and substitutable, the functional response will exhibit ranges of smooth change separated by rapid jumps between values, and different ranges of resource densities will result in a functional response with the characteristics of linearly substitutable or of non-substitutable resources. Adaptive functional response shape is dependent upon the tradeoff involved in raising each functional response. These results have implications for the types of indirect interactions that occur between resources as the result of a common consumer's functional response. They also suggest that the adaptive response of competing consumers to each other will differ depending on the nutritional status of the resources for which they are competing. Implications of these findings for consumer growth isocline shape and several other issues are explored.  相似文献   

9.
Mucosal tissues in the human female reproductive tract (FRT) are primary sites for both gynecological cancers and infections by a spectrum of sexually transmitted pathogens, including human immunodeficiency virus (HIV), that compromise women''s health. While the regulation of innate and adaptive immune protection in the FRT by hormonal cyclic changes across the menstrual cycle and pregnancy are being intensely studied, little to nothing is known about the alterations in mucosal immune protection that occur throughout the FRT as women age following menopause. The immune system in the FRT has two key functions: defense against pathogens and reproduction. After menopause, natural reproductive function ends, and therefore, two overlapping processes contribute to alterations in immune protection in aging women: menopause and immunosenescence. The goal of this review is to summarize the multiple immune changes that occur in the FRT with aging, including the impact on the function of epithelial cells, immune cells, and stromal fibroblasts. These studies indicate that major aspects of innate and adaptive immunity in the FRT are compromised in a site‐specific manner in the FRT as women age. Further, at some FRT sites, immunological compensation occurs. Overall, alterations in mucosal immune protection contribute to the increased risk of sexually transmitted infections (STI), urogenital infections, and gynecological cancers. Further studies are essential to provide a foundation for the development of novel therapeutic interventions to restore immune protection and reverse conditions that threaten women''s lives as they age.  相似文献   

10.
Soviet psychologists' views of the relationship between psychology and Pavlovian psychophysiology (or the study of higher nervous activity, as it is referred to in the Soviet literature) has long been a matter of curiosity and concern in the United States. Not accidentally, it has also been a matter of concern and dispute within the USSR. The following is an excerpt from a work by one of the Soviet Union's most seminal psychological theorists on this issue. Written in the late 1920s, this essay remains a classic statement of Soviet psychology's commitment to both a historical, materialistic science of the mind and the study of the unique characteristics of human psychological processes.  相似文献   

11.
Eric Vogelstein has defended Don Marquis' ‘future-like-ours' argument for the immorality of abortion against what is known as the Identity Objection, which contends that for a fetus to have a future like ours, it must be numerically identical to an entity like us that possesses valuable experiences some time in the future. On psychological accounts of personal identity, there is no identity relationship between the fetus and the entity with valuable experiences that it will become. Vogelstein maintains that a non-sentient fetus nonetheless has a future like ours because it is numerically identical with a future organism that has a mind that bears valuable experiences. Skott Brill, drawing on Jeff McMahan's embodied mind account, denies that human organisms directly have experiences, claiming that they only have experiences derivatively by virtue of their thinking part, and the loss of a future like ours is not transferred to the organism. I show that on McMahan's account, a strong case can be made for the organism having experiences directly, and the subject having these experiences derivatively. This negates Brill's reasoning, although it does imply that non-sentient fetuses do not have a future like ours in quite the same way as we do. I conclude that this is not problematic for Marquis' argument.  相似文献   

12.
The naturalist Alfred Russel Wallace (1823–1913) has for many years been standing in the shadow of his more famed co‐discoverer of the principle of natural selection, Charles Darwin. Despite outward similarities between the two men's formulation of the principle, Wallace had fit his appreciation of natural selection into views on evolution that were quite different from Darwin's. A closer examination of what Wallace had in mind suggests a model of process in which natural selection per se acts as the negative feedback mechanism (actually, a ‘state‐space’) in the relation between population and environment, and environmental engagement as made possible by the resulting selection of traits acts as the positive feedback part of the cycle. Thus, it may be better to contextualize adaptive structures as entropy‐relaying biogeochemical facilitators that only ‘generate a potential for evolution’ than to portray them as the end results of evolution. This systems point of view better lends itself to appreciations of the biogeographical context of evolution than does the tree‐thinking of a more conventional style of speciation‐focused Darwinism, which sometimes confuses process with result.  相似文献   

13.
禁牧政策下宁夏盐池县农户适应策略及其影响因素   总被引:1,自引:0,他引:1  
路慧玲  周立华  陈勇  马兵  魏轩 《生态学报》2016,36(17):5601-5610
禁牧政策下农户的适应策略是农户为了应对外界干预而做出的各种适应性改变,生计变化是其中最重要的部分。通过实地调查获得研究数据,对比分析禁牧初期和禁牧10a农户生计模式、养殖及种植方面的变化,并以农户的生计资本作为自变量,运用有序多分类和二项的Logistic回归模型分析农户适应策略(农户生计多样性、养殖规模及养殖方式)变化的影响因素。研究得出:1与禁牧初期相比,当前农户的适应策略主要表现为农户生计模式具有初步非农化倾向,生计多样性增加,大部分农户养殖规模减小或不变,农户生产结构有所调整,粮食作物种植面积增加,而经济作物种植面积减小,单只羊的养殖成本增加。2农户生计资本水平对其适应策略具有重要影响,农户生计多样性变化的主要影响因素有人力资本、金融资本和社会资本;影响农户养殖规模变化的主要有自然资本、物质资本、金融资本和社会资本,而影响农户养殖模式选择的主要是物质资本和金融资本因素。  相似文献   

14.
Uncultivated foods have received little attention in the scientific literature and nutrition programs of Mexico because they are usually seen as complementary to agricultural activities, i.e., corn planting and harvesting. Using an ecosystem approach to human health, this article examines the availability, nutritional contribution, and consumption patterns by gender and age of such foods in Ixhuapan and Ocozotepec, two native communities of southern Veracruz, Mexico. The research shows important differences between both communities. Ixhuapan has a more uniform environment and its people have opted for commercial activities and land parceling. Land use changes have led to a decrease in the number of people engaged in subsistence agriculture, environmental degradation, lower corn yields, and the loss of traditional, uncultivated foods. These changes have had a negative impact on the nutritional status of Ixhuapan children and adults, particularly women. Within each community, however, there are also important differences in terms of access to resources based on gender and age. Men catch game and large fish while women catch shrimp. Men gather seasonal plants in the forest while women gather wild weeds in the cornfields and spices in their backyards. Boys, more often than girls, obtain fruits from trees located in their backyard or the town’s public spaces. The article shows that women’s food resources are frequently consumed and constitute good sources of micronutrients.  相似文献   

15.
Infant feeding occurs in the context of continued gender inequities and in the context of a feminist movement that left women vulnerable to a system that defined the male body and mind as the norm. This paper draws from a qualitative analysis of interviews conducted with women artists at the 2005 Mamapalooza music festival in New York City, and conference participants at the 2005 La Leche League International and International Lactation Consultant Association Conferences and at the 2007 Reproductive Freedom Conference to understand our collective alienation from breastfeeding and to outline a process for how we might repossess breastfeeding as a positive function in women's lives. These women find power in honoring and validating their own experiences, in claiming those experiences as legitimate feminist actions, and then drawing on these experiences to seek new meanings, customs and norms that similarly honor, value and support their rights to those experiences. They argue that we need a feminist movement that fully incorporates women's needs as biological and reproductive social beings, alongside their needs as productive beings, and a movement that defines the female body and mind as the norm.  相似文献   

16.
Recent figures suggest that in Britain today, 77.3% of black women are engaged in full-time paid work, a figure which has remained fairly consistent since the introduction of statistical data assessing the work activity of African-Caribbean women from post-war years (CRE 1997). The study addresses the extent to which black women's high work rate derives from a combination of historical cultural and structural economic factors. Historical and cultural, because the experiences of slavery, colonialism and economic migration have had a direct impact on black women's relationship to full-time paid work today in contemporary Britain. In addition, structural economic factors such as high rates of unemployment for black men and lower rates of pay for black men and women compared to their white male and female counterparts, actively encourage a high proportion of black women towards full-time paid work in order to make up for this economic shortfall. A primary consequence of these inter-locking factors is that full-time paid work becomes central to black women's mothering and black mothers' work status is part of their everyday family experience.  相似文献   

17.
The typical approach used to identify and characterize adaptations is discussed briefly, and then it is applied to psychological changes associated with the psychological pain experienced by rape victims. It has been hypothesized that mental pain may reflect psychological adaptation that is designed to detect and cope with the occurence of social problems that reduce an individual's inclusive fitness in human evolutionary history. According to the hypothesis, mental pain is brought about by social tragedies in the lives of individuals and focuses the attention of individuals on the events surrounding the pain, promoting correction of the pain-causing events and their avoidance in the future. The hypothesis applied to rape victims proposes that in human evolutionary history raped females had increased fitness as a result of mental pain, because the pain forced them to focus attention on the fitness-reducing circumstances surrounding rape, which are discussed. Some of the hypothesis' predictions about the psychological pain of rape victims are examined using a data set of 790 rape victims in Philadelphia (USA) who were interviewed about their psychological traumatization within five days after the assault. The analyses indicate that, as predicted, a victim's age and marital status are proximate causes of the magnitude of psychological pain following rape. Reproductive-aged women appear to be more severely traumatized by rape than older women or girls and married women more than unmarried women. The results presented suggest that the psychology that regulates mental pain processes information about age and mateship status in the event of a women's rape.  相似文献   

18.
After only six months, a commerce-free internet-based milk-sharing model is operating in nearly 50 countries, connecting mothers who are able to donate breast milk with the caregivers of babies who need breast milk. Some public health authorities have condemned this initiative out of hand. Although women have always shared their milk, in many settings infant formula has become the "obvious" alternative to a mother's own milk. Yet an internationally endorsed recommendation supports mother-to-mother milk sharing as the best option in place of a birth mother's milk. Why then this rejection? Several possibilities come to mind: 1) ignorance and prejudice surrounding shared breast milk; 2) a perceived challenge to the medical establishment of a system where mothers exercise independent control; and 3) concern that mother-to-mother milk sharing threatens donor milk banks. We are not saying that milk sharing is risk-free or that the internet is an ideal platform for promoting it. Rather, we are encouraging health authorities to examine this initiative closely, determine what is happening, and provide resources to make mother-to-mother milk sharing as safe as possible. Health authorities readily concede that life is fraught with risk; accordingly, they promote risk-reduction and harm-minimisation strategies. Why should it be any different for babies lacking their own mothers' milk? The more that is known about the risks of substituting for breast milk, the more reasonable parental choice to use donor milk becomes. We believe that the level of intrinsic risk is manageable through informed sharing. If undertaken, managed and evaluated appropriately, this made-by-mothers model shows considerable potential for expanding the world's supply of human milk and improving the health of children.  相似文献   

19.
This research tests the hypothesis that change over time in women’s status leads to improvements in their children’s health. Specifically, we examine whether change in resources and empowerment in mother’s roles as biological mothers, caregivers, and providers and social contexts that promote the rights and representation of and investment in women are associated with better nutritional status and survival of young children. Analysis is based on a broad sample of countries (n = 28), with data at two or more points in time to enable examination of change. Key indicators of child health show improvement in the last 13 years in developing nations. Much of this improvement—90 percent of the increase in nutritional status and 47 percent of the reduction in mortality—is associated with improving status of women. Increased maternal education, control over reproduction, freedom from violence, access to health care, legislation and enforcement of women’s rights, greater political representation, equality in the education system, and lower maternal mortality are improving children’s health. These results imply that further advancement of women’s position in society would be beneficial.  相似文献   

20.
Objective: To examine health and psychosocial correlates of persistent thinness in black and white young adult women. Research Methods and Procedures: 1830 females (n = 988 black, n = 842 white) who participated in the National Heart, Lung, and Blood Institute Growth and Health Study were asked to indicate their current body size from a series of nine pictograms (1, emaciated to 9, obese). Persistent thinness was defined as having at least seven non‐missing measurement points between ages 9 to 18 with a body size rating of <4 at all points. Generalized linear models were used to examine whether persistently thin women differed from comparison women on cardiovascular disease risk factors measured at age 18.5 and psychosocial variables measured at age 21.5. Prospective associations between psychological measures in childhood and persistent thinness through the course of adolescence were also examined. Results: In the sample, 145 women (7.9%) met criteria for persistent thinness and 1685 women (92.1%) were classified as not persistently thin. Persistently thin women had a later age of menarche, fewer weight concerns, and healthier eating attitudes, were less likely to have had a child, came from higher socioeconomic backgrounds, and had significantly lower blood pressure and higher high‐density lipoprotein‐cholesterol than comparison women. Differences were not found on measures of depression or health services use. Girls with higher self‐esteem in childhood were more likely to remain persistently thin throughout adolescence. Discussion: Persistently thin women seem to be healthier on several indicators relative to comparison women, and race did not moderate these differences.  相似文献   

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