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1.
The different levels of media access in otherwise very similar villages in rural Nicaragua provided a natural laboratory to explore the effect of television (TV) access on men's preferences for female body size and shape. In study 1 we compared the female body ideals of men from three discrete villages who experienced different levels of TV but otherwise inhabited a similar ecological and sociocultural environment. 3D modelling software enabled participants to create their ideal female body with more precision than simply choosing a figure from a limited range of 2D images. In study 2 we further explored local men's perceptions of female physical attractiveness and attitudes towards television using focus group discussions. Results from study 1 showed that men in the high TV villages preferred significantly slimmer bodies compared to those in the low TV village. Regression analyses showed TV access to be a significant predictor of ideal body size and upper body shape, but not of ideal lower body shape. The central theme to emerge from study 2 was the importance of the relationship between lower body shape, movement, and sex in the men's judgments of female attractiveness: the curvaceous body was perceived by the men to be a reliable cue to potential sexual promise, rather than valued simply for its visual aesthetic. Overall, findings suggest that TV access is linked to rural Nicaraguan men's perceptions of ideal female body weight and breast size, but preferences for a curvaceous lower body shape may be driven primarily by judgments of female sexual promise.  相似文献   

2.
Sexual dimorphism is hypothesized to be the result of differential selection pressures between the sexes. Dimorphic traits can serve as indicators of mate quality, altering mate preferences in the opposite sex in favor of a conspicuous trait. Common indicators of mate quality include color and size, with traditional assumptions and evidence predicting a preference for more colorful and/or larger sized mates in many species. Both male and female preferences for more colorful and larger mates within a species are rarely examined simultaneously, however. We examined a sexually dichromatic freshwater fish, Percina roanoka and found that male coloration is positively correlated with size, suggesting color may function as an indicator of viability. We tested preferences for coloration and size in both sexes in a dichotomous mate choice setup in which only visual signals were exchanged. Neither females nor males exhibited a color or size preference in individuals of the opposite sex. Visual cues alone therefore appear to be insufficient to elicit a significant preference in both sexes of this species. Male coloration in P. roanoka does not appear to be driven solely by female preference.  相似文献   

3.
A large research literature indicates that men perceive women as more attractive when they are at high fertility than at low fertility within the ovulatory cycle. However, it remains unclear whether women also perceive women as more attractive at high fertility. This study examined women's ratings of samples of natural body odor collected from naturally-cycling women at high and low fertility within the cycle and from hormonal contraceptive-using women at mid-cycle. Like men, women rated naturally-cycling women's high-fertility scent samples as more attractive than their low-fertility samples. Women rated hormonal contraceptive (HC) users' scent samples as more attractive than naturally-cycling women's high- and low-fertility samples, though the difference between HC and high-fertility samples was statistically significant only when raters were treated as the unit of analysis. These findings reveal a potentially important role for scent communication in women's perceptions of other women and are consistent with the notion that the ovulatory cycle could influence women's interactions with one another. The findings also highlight the need for rigorous investigations of the possible impacts of hormonal contraception on women's attractiveness and social relationships with other women.  相似文献   

4.
Human breasts are larger and more enduring than reproductively necessary. It is thus unclear why this costly, yet conspicuous phenotype has been selected for, or what information they might convey about the underlying quality of the female. Following previous research on fluctuating asymmetry, we postulated that breast symmetry would predict a marker of mucosal immunity (salivary immunoglobulin-A; sIgA). Anthropometric breast measurements were provided by 97 young women. Controlling for Body Mass Index (BMI), breast size, and volume, results demonstrated that breast asymmetry predicted lower sIgA, whereas size and volume did not. Results support the hypothesis that symmetrical female breasts are a cue to underlying immunocompetence.  相似文献   

5.
Physical appearance provides a wealth of information concerning an individual's biological fitness and reproductive quality, but we do not know whether parents make use of this information when evaluating potential partners for their offspring. This is critical to our understanding of human mate choice, because parents frequently influence their offspring's mating decisions, either directly, for instance through arranged marriages, or indirectly, through manipulating their offspring's partner choice. Here, we used facial images that varied in attractiveness, masculinity, health, and symmetry to assess both reproductively-aged daughters' and their parents' preferences in potential mates for the daughters. In line with our predictions, both daughters and their parents had clear preferences for markers of genetic quality, although the daughters showed significantly stronger preferences for these markers than their parents. Contrary to previous research, parents and daughters did not have stronger preferences for markers of genetic quality if they perceived the daughter to be more attractive. Parents' preferences for the facial markers of genetic quality in their offspring's partner may help maximize inclusive fitness.  相似文献   

6.
Physical characteristics, such as breast size and waist-to-hip ratio (WHR), function as important features used by human males to assess female attractiveness. Males supposedly pay attention to these features because they serve as cues to fecundity and health. Here, we document that women with higher breast-to-underbreast ratio (large breasts) and women with relatively low WHR (narrow waists) have higher fecundity as assessed by precise measurements of daily levels of 17-beta-oestradiol (E2) and progesterone. Furthermore, women who are characterized by both narrow waists and large breasts have 26% higher mean E2 and 37% higher mean mid-cycle E2 levels than women from three groups with other combinations of body-shape variables, i.e. low WHR with small breasts and high WHR with either large or small breasts. Such gains in hormone levels among the preferred mates may lead to a substantial rise in the probability of conception, thus providing a significant fitness benefit.  相似文献   

7.
Senile dementia, of which the most common cause is known as Alzheimer's disease, is a neurological disorder characterized clinically by memory and learning deficits. The disease may be shown to have a prevalence rate in the United States of greater than three per 1000 of the general population, and it may be shown that at any one time 600,000 individuals are affected by advanced stages of this disease. The disease, unique to man, is relentlessly progressive and refractory to treatment. In most cases, it is unrelated to cerebral vascular insufficiency, it is however associated with well defined morphological and biochemical changes at the cellular level. These include altered dendritic morphology, intracellular changes such as granulovacuolar and neurofibrillary degeneration, and extracellular deposits termed neuritic plaques. Moreover, a selective dysfunction in central cholinergic mechanisms has been demonstrated. Recent results from this laboratory have indicated that significant changes in chromatin conformation may be demonstrated to occur in this disease. Specifically, a significant “heterochromatization” was found to occur in chromatin from brains of patients who had died with this disease, suggesting that a major alteration in chromatin structure may be related to the etiology of this condition. In addition, an accumulation of the environmental agent aluminum upon brain cell chromatin has been implicated to contribute to the pathophysiology of Alzheimer's disease. During the past few years it has become possible to model several of the morphological markers of this disease in the laboratory. Specifically, the paired helical filament, representing a major intracellular marker can now be induced in cultured neurons and a filamentous hyperplasia similar to neurofibrillary degeneration, but not identical in morphology, may be induced in experimental animals and in neurons in vitro by trace amounts of aluminum. The understanding of Alzheimer's disease is in its infancy, however, the availability of model systems now permits extensive investigations into the nature and mechanisms of the agents responsible for the changes observed.  相似文献   

8.
It has been suggested human female breast size may act as signal of fat reserves, which in turn indicates access to resources. Based on this perspective, two studies were conducted to test the hypothesis that men experiencing relative resource insecurity should perceive larger breast size as more physically attractive than men experiencing resource security. In Study 1, 266 men from three sites in Malaysia varying in relative socioeconomic status (high to low) rated a series of animated figures varying in breast size for physical attractiveness. Results showed that men from the low socioeconomic context rated larger breasts as more attractive than did men from the medium socioeconomic context, who in turn perceived larger breasts as attractive than men from a high socioeconomic context. Study 2 compared the breast size judgements of 66 hungry versus 58 satiated men within the same environmental context in Britain. Results showed that hungry men rated larger breasts as significantly more attractive than satiated men. Taken together, these studies provide evidence that resource security impacts upon men’s attractiveness ratings based on women’s breast size.  相似文献   

9.
In animal species where females mate with multiple males, female mating success might be expected to covary with aspects of female morphology, such as size or shape. Spiders are especially interesting in this regard, as the females of several spider groups weave intricate webs that often accommodate multiple male spiders, all of whom are potential mates. Because web design is likely to be dependent on female size/shape, we use multivariate methods to assess the relationships among female morphology, web design, and reproductive ecology over a range of body sizes in the orb-weaving spider Nephila clavipes . Of the measured variables, only abdomen size explained a significant amount of the variation in number of males on a web, and this relationship holds even after statistically accounting for body size. Because abdomen size is an indicator of body condition in spiders, we suggest that condition is likely to be an important factor relating to potential mating success in female spiders. We found no evidence for an association between web design and number of males on a web, although our data indicate that larger females build webs that are both larger and further from the ground than those of smaller females.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 87 , 95−102.  相似文献   

10.
Successful behavioral-based control methods rely on the accurate knowledge of the mating dynamics of the target insect. Age at first mating affects reproductive potential and the chance of multiple mating. The cabbage moth, Copitarsia decolora (Guenée) is an important pest of a number of commodities. We investigated combinations of age, body size and mating history to determine how these variables affect insect reproductive capacity. Fecundity and fertility decreased as the age of mating pairs increased, heavy and average sized females laid more eggs than light females. Female multiple mating did not enhance fecundity nor fertility potential. Furthermore, spermatophore size did not determine female re-mating behavior. However, female fecundity and fertility was related to the male mating history. Our results show that SIT is a valuable tool for controlling this pest.  相似文献   

11.
Male and female European Robins Erithacus rubecula display their red breasts in year‐round territorial contests. Despite the clear signalling role of the red breast, little is known about its sexual dimorphism or trends in size when Robins age. We studied these patterns in resident and migrant Robins in a Mediterranean population. Both male and female first‐year Robins had smaller red breasts than second‐year individuals. Females, but not males, showed a reduction in badge area after the second year of life, leading to sexual dimorphism in red breast area in the oldest Robins. The grey fringe around the red breast showed a steady increase in width in males when ageing, but not in females, also leading to sexual dimorphism in this trait among oldest Robins. The contrast between the red breast and its surrounding grey fringe was higher than that between the breast and the back at both high and low environmental light intensities. This suggests that the grey fringe could function as a frame to highlight the perimeter of the red breast, and that the Robin’s plumage is equally suited to display in open areas and forest understoreys. Our study suggests that the extent of the red breast and its grey frame could confer information about the age and sex of the birds, and thus be used as a signal in territorial contests and mating decisions.  相似文献   

12.
Abstract. 1. Optimal clutch size theory predicts that individuals will oviposit the number of eggs that increases their fitness. In Anastrepha ludens Loew (Diptera: Tephritidae), females oviposit larger clutches in unripe (firm) fruits than in ripe (soft) fruits. The following hypotheses were tested: (1) Using fruit firmness as an indicator of fruit quality, A. ludens females vary the number of eggs per clutch every time they reach an oviposition decision. (2) Maximising offspring survival with respect to either unripe or ripe fruit requires placing large clutches in firm fruit and smaller clutches in soft fruit. 2. Agar spheres were used as artificial hosts. Three agar concentrations resulted in three degrees of firmness. Mango fruits Mangifera indica L. served as natural hosts. Ripe and unripe fruits were used to test soft and firm host conditions respectively. Females laid significantly larger clutches in the firmer artificial hosts than in the softer hosts. They also laid significantly more eggs in artificial hosts without sugar than in hosts with sugar. Firm (unripe) mangoes also received significantly larger clutches than soft (ripe) mangoes. 3. When an individual female was first presented with a firm artificial host, it laid a large clutch. If subsequently offered a soft host, the female laid a significantly smaller clutch. Finally, if again offered a firm host, clutch size was increased significantly. 4. Possible trade‐offs in offspring fitness were explored in ripe and unripe mangoes by measuring offspring egg‐to‐adult survival, pupal weight, mean adult longevity, and fecundity. Despite the fact that larval survival was greater in soft fruit than in firm fruit, parameters such as pupal weight, mean longevity, and fecundity of adults stemming from both fruit types did not differ significantly. 5. A probable trade‐off between high offspring mortality caused by host unsuitability and low offspring and adult mortality caused by parasitism and predation is discussed as the reason for the exploitation of sub‐optimal hosts.  相似文献   

13.
Research on optimal outbreeding describes the greater reproductive success experienced on average by couples who are neither too closely related, nor too genetically dissimilar. How is optimal outbreeding achieved? Faces that subtly resemble family members could present useful cues to a potential reproductive partner with an optimal level of genetic dissimilarity. Here, we present the first empirical data that heterosexual women select partners who resemble their brothers. Raters ranked the facial similarity between a woman's male partner, and that woman's brother compared to foils. In a multilevel ordinal logistic regression that modeled variability in both the stimuli and the raters, there was clear evidence for perceptual similarity in facial photographs of a woman's partner and her brother. That is, although siblings themselves are sexually aversive, sibling resemblance is not. The affective responses of disgust and attraction may be calibrated to distinguish close kin from individuals with some genetic dissimilarity during partner choice.  相似文献   

14.
BACKGROUND: Barrett's esophagus metaplasia is the key precursor lesion of esophageal adenocarcinoma. The aim of this study was to find a subset of markers that may allow the identification of patients at risk for esophageal adenocarcinoma, and to determine genes differentially expressed in esophageal squamous cell carcinoma. METHODS: Laser capture microdissection technique was applied to procure cells from defined regions. Genome-wide RNA profiling was performed on esophageal adenocarcinoma (n = 21), Barrett's esophagus (n = 20), esophageal squamous carcinoma (n = 9) and healthy esophageal biopsies (n = 18) using the Affymetrix Human Genome U133plus 2.0 array. Microarray results were validated by quantitative real-time polymerase chain reaction in a second and independent cohort and by immunohistochemistry of two putative markers in a third independent cohort. RESULTS: Through unsupervised hierarchical clustering and principal component analysis, samples were separated into four distinct groups that match perfectly with histology. Many genes down-regulated in esophageal cancers belong to the epidermal differentiation complex or the related GO-group “cornified envelope” of terminally differentiated keratinocytes. Similarly, retinol metabolism was strongly down-regulated. Genes showing strong overexpression in esophageal carcinomas belong to the GO groups extracellular region /matrix such as MMP1, CTHRC1, and INHBA. According to an analysis of genes strongly up-regulated in both esophageal adenocarcinoma and Barrett's esophagus, REG4 might be of particular interest as an early marker for esophageal adenocarcinoma. CONCLUSIONS: Our study provides high quality data, which could serve for identification of potential biomarkers of Barrett's esophagus at risk of esophageal adenocarcinoma progression.  相似文献   

15.
A patient with extensive juvenile hypertrophy of the breasts has been presented. Several interesting facts in the case history are as follows: After pregnancy, the breasts did not regress with "hormone shots" to stop lactation. The patient took high-dosage estrogen birth control pills for 3 years before the breasts started to grow rapidly. Within 1 month after reduction mammaplasty and despite 20 mg dydrogesterone per day, the breasts started to enlarge. A total of 60 mg b.i.d. of dydrogesterone did not stop breast regrowth. Tamoxifen citrate did cause regression of the breasts. After two reductions, the breasts regrew with a subsequent pregnancy. The breast tissue regrew in the axilla with a subsequent pregnancy after simple mastectomy-subcutaneous mastectomy and free nipple transplants. Chronic marijuana use may have an effect on the breast tissue in certain susceptible females as well as in some males. Much needs to be learned about the control of growth of female breast tissue.  相似文献   

16.
Size‐assortative mating is a nonrandom association of body size between members of mating pairs and is expected to be common in species with mutual preferences for body size. In this study, we investigated whether there is direct evidence for size‐assortative mating in two species of pipefishes, Syngnathus floridae and S. typhle, that share the characteristics of male pregnancy, sex‐role reversal, and a polygynandrous mating system. We take advantage of microsatellite‐based “genetic‐capture” techniques to match wild‐caught females with female genotypes reconstructed from broods of pregnant males and use these data to explore patterns of size‐assortative mating in these species. We also develop a simulation model to explore how positive, negative, and antagonistic preferences of each sex for body size affect size‐assortative mating. Contrary to expectations, we were unable to find any evidence of size‐assortative mating in either species at different geographic locations or at different sampling times. Furthermore, two traits that potentially confer a fitness advantage in terms of reproductive success, female mating order and number of eggs transferred per female, do not affect pairing patterns in the wild. Results from model simulations demonstrate that strong mating preferences are unlikely to explain the observed patterns of mating in the studied populations. Our study shows that individual mating preferences, as ascertained by laboratory‐based mating trials, can be decoupled from realized patterns of mating in the wild, and therefore, field studies are also necessary to determine actual patterns of mate choice in nature. We conclude that this disconnect between preferences and assortative mating is likely due to ecological constraints and multiple mating that may limit mate choice in natural populations.  相似文献   

17.
Needle aspiration cytology, immunocytochemistry and electron microscopic findings are described in a case of rare breast carcinoma with bizarre, malignant giant cells in a young female under age 30. The malignant tumors were found in both breasts; the first one was diagnosed when the patient was 23 years of age and the second one in the contralateral breast four years later. Based on our present findings, and in keeping with a similar case recently described by us as occurring in an elderly female, we thought that the bizarre giant cells in this rare breast carcinoma were of epithelial origin. The differential diagnosis of other conditions that may be associated with giant cells in breast aspirates is discussed.  相似文献   

18.
Body constitution plays an important role in human mate choice. Cross-cultural research reports that women on average prefer men with muscular physique. It is still unclear, however, what mechanisms influence the inter-individual variation in mate preferences and choices of partner's physique. In this study, we tested the mechanisms of an imprinting-like effect (similarity between father and an ideal and actual partner) and of homogamy (similarity between self and an ideal and actual partner) for male physique in heterosexual women and homosexual men. To assess the variation in male physique, we employed somatotype paradigm which characterizes body constitution using three components: endomorphic (heavy-set), mesomorphic (muscular), and ectomorphic (lean). In total, 149 homosexual men and 769 heterosexual women from the Czech Republic indicated the somatotype of their father, ideal and actual partner, and in homosexual men also their own somatotype. In line with previous research, the somatotype most preferred by both men and women was the mesomorphic, followed by the ectomorphic and the endomorphic one. Women's preferences for an ideal partner somatotype weakly correlated with their fathers' somatotype, especially in women who reported a positive relationship with their fathers during childhood. Among homosexual men, we found imprinting-like preferences only for the ectomorphic somatotype component and no significant association with the quality of their relationships with their fathers. We also found no significant relationship between the fathers' and actual partners' somatotype in either heterosexual women or homosexual men. Our research indicates that fathers have a rather weak influence on mate preference for somatotypes and no influence on actual mate choice.  相似文献   

19.
In subdioecious populations, functional female, male and hermaphrodite individuals coexist. Subdioecy may be a transitional state towards dioecy or a breakdown of dioecy, although lability in sex expression may maintain subdioecy as a stable condition. To better understand the ecological aspects involved in sex ratio dynamics and breeding system evolution, we studied the pollination and female fitness components of female and hermaphrodite individuals of the subdioecious shrub Fuchsia microphylla. In two natural populations at the Trans‐Mexican Volcanic Belt we estimated female frequency and several reproductive components of female and hermaphrodite plants under natural pollination and experimental pollination treatments. Average female frequency was 42%, and on average, 42.5% of hermaphrodites produced fruits. Female plants showed a 17‐fold female fertility advantage over hermaphrodites through increased fruit production, as the number of seeds and germination rates did not differ between morphs. Hermaphrodite flowers were larger, with similar nectar production and concentration to female flowers, and pollinators did not show consistent morph preferences. Some hermaphrodites produced fruits autonomously, and female flowers excluded from pollinators produced fruits putatively by apomixis. Fruit production in hermaphrodites, but not in females, was related to height, suggesting increased investment of hermaphrodites in the female function at higher resource status. For sex ratios to be at equilibrium, the female fertility advantage should be reduced about eightfold. However, it may be that hermaphrodites are maintained by producing fruits at no cost to the male function at higher resource status, as the gender plasticity hypothesis proposes.  相似文献   

20.

Background

S-phase kinase protein 2 (Skp2), an oncogenic protein, is a key regulator in different cellular and molecular processes, through ubiquitin-proteasome degradation pathway. Increased levels of Skp2 are observed in various types of cancer and associated with poor prognosis. However, in human breast carcinomas, the underlying mechanism and prognostic significance of cytoplasmic Skp2 is still undefined.

Methods

To investigate the role of cytoplasmic Skp2 expression in human breast carcinomas, we immnohistochemically assessed cytoplasmic Skp2, p-Akt1, and p27 expression in 251 patients with invasive ductal carcinomas of the breast. Association of cytoplasmic Skp2 expression with p-Akt1 and p27 was analyzed as well as correspondence with other clinicopathological parameters. Disease-free survival and overall survival were determined based on the Kaplan-Meier method and Cox regression models.

Results

Cytoplasmic of Skp2 was detected in 165 out of 251 (65.7%) patients. Cytoplasmic Skp2 expression was associated with larger tumor size, more advanced histological grade, and positive HER2 expression. Increased cytoplasmic Skp2 expression correlated with p-Akt1 expression, with 54.2% (51/94) of low p-Akt1-expressing breast carcinomas, but 72.6% (114/157) of high p-Akt1-expressing breast carcinomas exhibiting cytoplasmic Skp2 expression. Elevated cytoplasmic Skp2 expression with low p-Akt1 expression was associated with poor disease-free and overall survival (DFS and OS), and Cox regression models demonstrated that cytoplasmic Skp2 expression was an independent prognostic marker for invasive breast carcinomas.

Conclusion

Cytoplasmic Skp2 expression is associated with aggressive prognostic factors, such as larger tumor size, and advanced histological grade of the breast cancers. Results demonstrate that combined cytoplasmic Skp2 and p-Akt1 expression may be prognostic for patients with invasive breast carcinomas, and cytoplasmic Skp2 may serve as a potential therapeutic target.  相似文献   

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