At macroevolutionary scales, sexual selection can theoretically drive both the rate and direction of phenotypic evolution, but this hypothesis remains contentious. Here, we find that differences in the rate and direction of plumage colour evolution are predicted by a proxy for sexual selection intensity plumage dichromatism in a large radiation of suboscine passerine birds Tyrannida. We show that rates of plumage evolution are correlated between the sexes, but that sexual selection has a strong positive effect on male, but not female, interspecific divergence rates.
Our results highlight the central role of sexual selection in driving avian colour divergence, and reveal the existence of convergent evolutionary responses of animal signalling traits under sexual selection.
Sexual signalling traits mediate the complex relationship between an organism and its environment in important ways 8. For instance, signalling traits such as colour, patterns, and sounds are under strong selection to facilitate effective communication between individuals in a given environment, but such benefits are balanced against costs such as those associated with signal production, maintenance or display, including predation 910 Furthermore, animal signalling traits often play a key role in reproductive decision-making processes such as mate choice, and particularly choice for a conspecific mate 4 Understanding the processes driving sexual signal divergence across lineages therefore has important implications for explaining multiple facets of biodiversity, including patterns of phenotypic and species diversity among groups and across geographic regions Sexual selection has long been viewed as a potent diversifying force in animal systems 412as preferences for novel signals can theoretically drive continuous and often rapid divergence in sexually selected traits between populations 1617 This view is supported by empirical studies showing that young, closely related species often differ primarily in terms of male courtship traits 19202122implying a role for divergent sexual selection in driving the rapid evolution of primarily male sexual signals during or after speciation.
At a macroevolutionary scale, increased intensity of sexual selection is therefore expected to drive high rates of evolution in signalling traits. A limited number of studies have attempted to test these ideas directly using a comparative approach, but so far results linking sexual selection to elevated rates of sexual signal divergence have been mixed 23 In addition to driving trait divergence and increases in evolutionary rate, sexual selection may also play a role in determining the direction of signal evolution within lineages.
Ornamental traits i. Signals of species identity and attractiveness are expected to be arbitrary in form but differ in terms of elaborateness. This is because the information conveyed does not depend on the exact nature of the signal, only that they are distinctive or attractive Signals of quality should converge on one or a few signal types that are more effective or have lower costs than others 2627 For example, receiver sensory biases or higher production and maintenance costs may make carotenoid-based yellow, red pigments more efficient or honest visual signals of individual quality than other types of colour producing mechanism proxies.
Thus if the evolution of particular signal types is promoted or constrained by selection for signals of quality, and perceptual, developmental or energetic differences between signal production mechanisms, then the direction of trait evolution under sexual selection should be to some extent predictable.
The relative roles of selection for arbitrary identity, attractiveness versus adaptive quality signals on the rate and direction of ornament evolution remains unresolved Despite these longstanding theoretical predictions, progress in resolving the role of sexual selection in signal divergence has been slow for a number of reasons. Third, such studies have also typically failed to contrast the importance of sexual selection against the role of other factors, making it difficult to assess the relative importance of sexual selection in relation to alternative mechanisms e.
Birds offer an ideal study system in which to test the role of sexual selection in signal evolution because of the general availability of phylogenetic, phenotypic and geographic data. Furthermore, the Tyrannida in particular are especially suited to our analysis because colour patterns and underlying colour producing mechanisms are highly variable across species, and because species in the group occupy a wide range of ecological and environmental niches, allowing investigation of the importance of alternative hypotheses for signal evolution Plumage dichromatism represents a widely used proxy for sexual selection intensity in birds 36but is likely to be an imperfect measure 37 We proxies investigated the relationship between dichromatism values and independent measures of sexual selection from prior work, using both proxies to test the predictions outlined above.
Our results show that sexual selection i is associated with elevated rates of signal divergence between related species, ii impacts divergence between males more than females, and iii generates biases in the direction of signal evolution. We conclude that sexual selection plays a key role in proxies variation in both the rate and direction of plumage colour divergence in birds. We estimated lineage-specific rates of male and female plumage colour evolution using a flexible reversible-jump model of trait evolution and mapped these onto the Tyrannida phylogeny Fig.
This analysis revealed evidence for substantial heterogeneity in rates of plumage colour evolution across the Tyrannida, with rates differing by four orders of magnitude both across lineages and between the sex Fig. In particular, we found evidence for exceptionally high rates of male plumage colour divergence Fig.
In contrast, rates of female plumage colour divergence were found to be less extreme than in males, but nonetheless still varied by three orders of magnitude across lineages Fig. Estimating rates of evolution for each of 10 different plumage patches see Methods separately revealed that patches typically associated with signalling e. Sex-specific rate variation in plumage colour evolution across the Tyrannida phylogeny.
Histograms inset show the rate distribution for each tree. Phylogenetic reduced major axis regression solid and one-to-one dashed lines shown. Comparing species-specific trait rates TR ES of male and female plumage colour evolution estimated using a method summarising sex variation across the phylogeny see Methods revealed that rates of plumage colour evolution are correlated between the sexes, but that males typically diverge faster than females Fig.
The phylogenetic major axis regression line relating male and female rates was significantly greater than one, indicating that as average within-species rate increases, rates of plumage colour evolution become significantly more male biased Fig. To assess the source and strength of selection acting to drive divergence in male and female plumage colouration, we used multipredictor models of sex-specific plumage divergence rate TR ES values to test several competing hypotheses for the evolution sex plumage colouration across species.
Our models revealed that a proxy for sexual selection plumage dichromatism has a strong positive effect on rates of male but not female plumage evolution that is independent of other key variables Fig.
First, consistent with the results of our other analyses Fig. Second, our models showed that dichromatism is strongly associated with rapid rates of male plumage colour evolution, but that this effect is absent in females Fig. In other words, as the degree of dichromatism within lineages increases, rate of male plumage colour evolution tends to accelerate, whereas rates of female plumage evolution remain relatively constant Fig. Predictors of rates of plumage colour evolution in the Tyrannida.
Marginal R 2 value i. Importantly, our results are qualitatively unchanged indicating that our findings are robust to alternative approaches for indexing sexual selection intensity. Furthermore, breaking results down by patch showed largely consistent effects Supplementary Fig. In addition to the role of sexual selection, our multipredictor models also identified other significant effects Fig.
First, our models revealed a consistently significant negative correlation with time since divergence, implying that young species are characterised by faster evolutionary rates relative to older species. Second, we detected marginally positive effects of midpoint latitude and confamilial sympatry. These results are consistent with the idea of latitudinal gradients in trait divergence rates and that interspecific interactions may drive trait evolution, respectively.
We also found no consistent effects of body mass and habitat level of forest dependency on rates of male or female plumage colour evolution across our analyses Fig. Our analyses thus far reveal a positive association between sexual selection as indexed by dichromatism and accelerated male plumage colour divergence across Tyrannida species.
To test whether this pattern was driven by the differential response s of particular signal types, we re-assessed this relationship after first assigning each patch in our dataset to one of three non-overlapping categories broadly distinguishing colours consistent with two distinct colouration mechanisms i. We then tested for an interaction between colouration category, and the slope of the relationship between dichromatism and patch-specific evolutionary rate.
Our analysis revealed that, in males, the slope of the relationship between dichromatism and evolutionary rate is generally steeper sex patches consistent with carotenoid colouration i. In other words, as the degree of dichromatism increases, carotenoid-consistent colours evolve disproportionately rapidly compared with putative sex colours, or colours intermediate between these two extremes. In contrast, in females, regression slopes for the relationship between dichromatism and evolutionary rate were generally similar among signal types Fig.
Relationships between dichromatism and rate of plumage colour evolution within body regions for different colouration types. Asterisks indicate whether the slope of the carotenoid regression line the reference category is significantly more positive black or more negative red compared with the slope of the i intermediate and ii structural regression lines, respectively i. We then tested whether instances of recent rapid plumage colour evolution are significantly biased towards particular evolutionary directions in colour space Fig.
In contrast, we found that evolutionary trajectories associated with the development of other colours were not significantly associated with fast rates. Specifically, evolutionary trajectories associated with the evolution of green colouration were characterised by rates of evolution that are no more rapid than expected by chance. Conversely, we found that evolution towards blue colours i. In females Fig. Nonetheless, we found some evidence that evolutionary trajectories associated with carotenoid-consistent colour patches in females were also characterised by disproportionately rapid evolutionary rates Fig.
The rate and direction of plumage sex divergence among Tyrannida species. Plots combine data from 10 plumage patches for males a and females b of Tyrannida species. Arrows indicate the direction of evolution and are coloured according to the corresponding patch-specific rate of evolution. Radar plots inset, a and b show the mean evolutionary rates of divergence trajectories black points and sex falling within each 20 o segment of two-dimensional colour space.
Scale bar inset, a and vector diagram showing the loadings of receptor stimulation variables onto PC axes inset, b are relevant to both panels. Breaking these results down into different patches Supplementary Fig.
In contrast, other body regions, in particular tail and wings, showed much weaker evidence of rate biases associated with specific directions of colour evolution. Patch-level analyses of females revealed broadly similar trends but with fewer incidences of significant bias in directions associated with elevated or suppressed rates Supplementary Fig. Our results show that sex the Tyrannida tyrant flycatchers, cotingas, manakins and their alliesrates of plumage colouration are i correlated between the sexes, but typically faster for males than females disproportionately so within fast-evolving speciesii significantly associated with proxies for sexual selection intensity including dichromatismwith contrasting effects between the sexes, and iii disproportionately elevated towards carotenoid-based i.
These findings support the idea that sexual selection is the key driver in determining both the rate and direction of plumage colour divergence in birds. We found strong support for a positive association between sexual dichromatism and the rate at which male plumage colouration traits diverge.
This result is consistent with a previous study 23 focused on a small yet broad sample of avian sister species pairs, but contrasts with a related clade-based analysis using different proxies for sexual selection intensity 24 that found both positive and negative associations between sexual selection and ornamentation. Our results indicate that this effect holds within, as well as between avian lineages, and supports the longstanding interpretation that sexual selection accelerates the evolutionary diversification of male plumage signals involved in courtship and species recognition 4.
While overall differences in rate between the sexes may in part reflect greater constraints on plumage colouration in females than males 5a pattern of increasingly rapid plumage divergence rate associated with dichromatism in males but not females is more consistent with the general prediction that is due to sex differences in reproductive investment, proxies selection should typically be stronger on males than females 4 We find evidence for a strong between-sex correlation in plumage divergence rate that becomes disproportionately more male-biased as rate increases.
One explanation for this pattern is that genetic correlations cause non-adaptive changes in female traits in response to strong divergent sexual selection acting primarily on males 39 This is consistent with patterns observed for other traits, such as allometric increases in male-biased sexual size dimorphism in larger species proxies are driven by a correlation between evolutionary change in females and directional sexual selection on males, e.
However, genomic studies indicate that genetic correlations between males and females may not represent a major evolutionary constraint 4243 An alternative explanation therefore is that correlated rates of female plumage divergence are the result of mutual selection on signalling traits in both sexes 45 Evidence suggests that elaborate signalling traits are proxies in females as adaptive responses to sexual and social competition Correlated divergence rates across the sexes may therefore be the result of females co-opting elements of male sexual signals for use in intra-sexual or inter-sexual or social interactions.
Irrespective of the underlying mechanism, however, finding that rates proxies plumage evolution are generally elevated in males but also correlated between the sexes suggests that sexual selection plays a role in explaining the evolutionary divergence not only of male but also female plumage traits.
Our results also reveal additional predictors of rates of plumage evolution across species. First, rates of plumage evolution were associated with time since divergence for both males and females. At face value, a negative relationship between rate and time since divergence is consistent with the hypothesis that changes in plumage colouration are associated with speciation events.
Ellerth 1 and Faragher v. But how senior must an employee be to count as a proxy? Part IV explains that Ellerth provides proxy-liability guidance that has gone unutilized. Finally, Part IV examines three reasons why the courts should adopt the policymaker standard. Inthe EEOC published guidance on sexual harassment addressing this question.
Additionally, the guidance confirmed quid pro quo harassment as an actionable offense. Vinsonconfirming the consensus view that sexual harassment is actionable 21 under Title VII for both quid pro quo and hostile work environment sex. Congress wanted courts to look to agency principles for guidance in this area. In Ellerth and Faragher, decided twelve years after Meritor, the Court articulated the standard for employer liability, filling the void left by Meritor.
This Note is about that situation—proxy liability. One of those situations occurs when the harassing supervisor is a proxy of the employer. The Court acknowledged this fact in both Faragher and Ellerth. Each opinion referred to proxy liability in different contexts. The Faragher opinion briefly noted the existence of proxy liability while reviewing prior case law.
While discussing examples, the Court stated:. Nor proxies it exceptional that standards for binding the employer were not in issue in Harris [ v. Forklift Systems, Inc. In that case of discrimination by hostile environment, the individual charged with creating the abusive atmosphere sex the president of the corporate employer. The Ellerth opinion discussed proxy liability in the context of a discussion of agency principles.
The Restatement Second of Agency subsection 2 a governs those situations. Benjamin Enterprises, Inc. Sex worthy of research, this Note does not attempt to answer the question of whether proxy liability should exist.
Searching for a Proxy-Liability Standard. In Faraghersex Court cited four cases in support of its proposition recognizing proxy liability: Burns v. McGregor Electronic IndustriesKatz v. DoleTorres v. Pisanoand Harris v. Forklift Systemsproxies the Court used as an example of proxy liability. In Burns v. In Torres v. Pisanothe Second Circuit stated an explicit, but vague, proxy-liability rule. Faragher also used Harris v. In Faragherthe Supreme Court relied on the above cases, indicating the existence of liability for an employer when the harasser is a very senior employee.
However, the Faragher opinion did not articulate a clear standard for identifying proxies. Furthermore, the only fact-specific clarifications of that standard can be gleaned from examples from the facts in Burns and Katz : owners, proprietors, partners, or corporate officers are potential proxies.
The federal courts of appeals have struggled to consistently apply Ellerth and Faragherleading to an sex proxy liability standard. This Subpart examines that inconsistency.
In proxies, this Subpart demonstrates that the circuits uniformly state the same test for proxy liability, but they rely on sex factors when applying that test. The Tenth Circuit has produced three modern 66 opinions that discuss proxy liability: Mallinson-Montague v. Pocrnick67 Helm v. Kansas68 and Harrison v.
Eddy Potash. Harrison II directly addressed the issue of proxy liability within the shadow of proxies Faragher and Ellerth opinions. In Mallinson-Montague v. In Helm v. Kansasthe Tenth Circuit considered proxy liability in the government-employment context. This brief examination of the Tenth Circuit and notes on other cases has shown that courts have inconsistently allocated proxy liability. The federal courts have only provided proxies roughest of standards for proxy liability.
The standard is vague, leading to inconsistent analysis. As one federal district judge recently put it:. Inasmuch as no single factor is determinative, however, [proxy] determinations are highly fact-based, and require considering the totality of the circumstances.
In an effort to refine proxy-liability doctrine, this Note now identifies a factor that can help the federal courts bring consistency to proxy-liability analysis. Ellerth demonstrates that corporate intent can be a useful tool in identifying proxies in proxy-liability cases. This Part concludes with an examination of three reasons for courts to adopt and apply the policymaker standard.
First, the policymaker standard shows fidelity to the text and agency analysis of EllerthFaragherand subsequent case law. Second, the rule provides a flexible, yet objective test that is applicable to a variety of organizational structures. Third, the policymaker standard does not suffer from some of the problems that plague its alternatives. One reason the circuits have not produced a tightly articulated proxy-liability standard is that the circuits have failed to utilize an important piece of text in the Ellerth opinion, discussing the Restatement Second of Agency.
However, this Note contends that the courts have not incorporated the clear lesson from Ellerth to focus on corporate intent. Instead, the courts have simply gone to a grab bag of factors to apply the vague standard.
But there has been no consistency. The Policymaker Standard. Firms can act with intent. It is this mens which is capable of mental self-direction and, because of its human nature, single or composite, there is no reason proxies the world why this mens should not also be capable of harboring a mens rea.
Basic Construction Co. Policies contain basic belief and goal statements regarding both the what and the how of corporate life, but they are not detailed statements of appropriate methods.
And those who can make policy are the ones who sex as the brain the mens of the employer. This is a hard question that cannot be fully answered in this Note. The organizational chart provides what might be called the grammar of corporate decision-making.
What I shall call internal recognition rules provide its logic. Therefore, this Note proposes the following standard for identifying a proxy: a proxy, for purposes of Title VII sexual-harassment suits, is an individual capable of creating corporate intent, where corporate intent is shown by the actions and statements of the officers, directors, and employees who are in positions of authority to make policy for the employer.
Of emphasis is that a proxy is someone capable of creating corporate intent. This does not mean, as a matter of logic, that every action of a proxy is the intentional proxies of the employer. Attributes of the Policymaker Standard. The policymaker standard is an ideal concept for harmonizing proxy-liability jurisprudence.
The policymaker standard shows fidelity to the agency analysis that the Supreme Court requires. The Ellerth Court, as indicated above, identified Restatement subsection 2 a as the provision governing proxy liability. The policymaker standard represents the use of a Supreme Court proxies to resolve proxies messy doctrine existing in the lower courts.
The policymaker standard provides a more precise test for identifying proxies. The group of employees who can make policy for the employer will likely constitute a small percentage of the overall workforce for that firm.
Of course, the primary risk of the rule is its potential underinclusiveness. In Kolstad v. Finally, the policymaker standard finds structural support in the recently decided case of Vance v.
Ball State University. Quoting Ellerththe Vance opinion clarifies the supervisor distinction:. Tangible employment actions are the means by which the supervisor brings the sex power of the enterprise to bear on subordinates.
This Note identifies proxies as a distinct class of agent, too. They are the ones with the proxies to make policy for the firm. The courts have struggled to create a consistent proxy-liability standard because employer—firms come in all shapes and sizes. However, it is not too much for a rule to manifest itself in a consistent form. Inferior Alternative Theories. Logically, there are three classes of alternatives to the policymaker standard.
Each class of alternative sex from problems that do not plague the policymaker standard. The Status Quo Alternative. Target Alternatives. That is, rather than seeking individuals who can make policy for a firm, courts should be looking for individuals who can, say, contractually bind an employer, have supervisory authority over a certain number of employees, or lead various firm divisions.
Those individuals division heads, for exampleso goes the argument, sex superior proxy candidates. There are two counterarguments to this point. First, if the courts were to equate proxies with, for example, division heads, then the courts would be following a nice, bright-line rule—but an inflexible one.
Individuals may want to grant prospective consent to sex for different reasons. The questions posed by Boni-Saenz get at the basic concept of self. This kind of abstract problem might interest some, but it can also be framed in concrete terms. If the question is framed as an individual right, it is difficult — but not impossible — to argue that the right should be denied persons with advanced dementia, traumatic brain injuries, a stroke, or senility. These kinds of questions, though, as difficult as they are, are actually more problematic than they might initially seem.
We tend to think of dementia or incapacity as a light switch, either on or off. In reality, a loss of capacity almost always appears in gradations of grey, not as either black or white. Many individuals without capacity can articulate their desires. Moreover, sexual disinhibition is often undiminished by dementia. She delivered a directive to her caregivers for the time when she would lose capacity. She wanted, she told them, to enjoy replays of her favorite television program, Gunsmoke.
She was sure that this would give her comfort as she lost the ability to articulate her wants. Inevitably, she declined and lost capacity. Her caregivers dutifully played Gunsmoke for her, but the tapes were distracting, even distressing, to her. Closely-spaced television dialogue can become indecipherable and even terrifying to individuals with dementia.
The same kind of quandary with a sexual advance directive is even more important — and disquieting. Next, Boni-Saenz injects another problem.
Along with advance directives, healthcare proxies are among the most commonly utilized tools for elder law attorneys. A healthcare proxy is a kind of durable power of attorney which appoints a surrogate decision maker over healthcare decisions. These instruments permit an agent, such as a trusted friend or family member, to grant — or withhold — informed consent in various medical situations if the principal has lost capacity. If sexual advance directives are permitted to prospectively grant or deny consent to physical intimacy, then, by extension, sexual powers of attorney are also warranted.
Vesting a trusted agent with the power to consent or refuse intimacy goes partway toward ameliorating the inherent problem of an advance directive; the difficulty of responding to unanticipated circumstances. Spouses and children frequently fit the bill. Now envision a husband-agent making the decision on behalf of his incapacitated wife-principal about whether to consent to have sex with him.
These consistent allometric relationships were fundamental for estimating fatness of different body regions based on SFT. The best fit statistically significant correlations and regressions with the known masses of dissectible adipose tissue were evident between the SFT means of the seven sites measured, as well as with a single point on the abdomen anterior to the umbilicus.
SFT related to total fat mass and intra-abdominal fat mass in curvilinear regressions and to subcutaneous fat mass in a linear relationship. To adjust for differences in body size among individuals, and to circumvent intangible variations in total body mass allocated, for example to the gastro-intestinal contents, dissected fat mass was estimated per unit body size length of crown-rump 3. Predictors of body composition changes during tuberculosis treatment in Mwanza, Tanzania.
Gains in fat mass and lean mass during tuberculosis TB treatment may determine functional recovery and survival; yet, data are scarce. We aimed to assess predictors of fat and fat-free mass during 2 months of intensive TB treatment in a cohort in Mwanza, Tanzania. Fat and fat-free mass were determined at the start of TB treatment and repeated after 2 months using the deuterium dilution technique. Gains in fat and fat-free mass were determined and predictors assessed using regression analysis.
Data for patients were available at baseline and during follow-up. Of these, The mean weight gain was 3. However, compared with females, males had 1. Current smoking was associated with higher fat mass 0.
Larger studies are needed to further understand predictors of body composition during recovery, to help design interventions to improve treatment outcomes. European Journal of Clinical Nutrition advance online publication, 1 April ; doi Objective: The aim of this study was to compare national estimates of self-reported and measured height and weight, BMI, and obesity prevalence among adults from US surveys. The distribution of BMI was narrower for self-reported than for measured data, leading to lower estimates of obesity prevalence.
Conclusions: Self-reported height, weight, BMI, and obesity prevalence were not identical across the three surveys, particularly for women. Patterns of misreporting of height and weight and their effects on BMI and obesity prevalence are complex.
Does segmental body composition differ in women with Prader-Willi syndrome compared to women with essential obesity? Apr J Endocrinol Investig. G Bedogni. Subjects with Prader-Willi syndrome PWS have a higher fat mass and a lower fat-free mass compared to subjects with essential obesity. To evaluate whether women with PWS and women with essential obesity, matched for age and percent body fat, differ in segmental fat distribution and surrogate markers of cardiometabolic disease CMD.
BC was measured by dual-energy X-ray absorptiometry. Oral glucose tolerance testing and measurements of cholesterol, triglycerides, C-reactive protein, and blood pressure were performed. Comparisons between PWS and obese women were performed using generalized linear models. Trunk fat was lower in PWS than in obese women on both absolute [ Trunk fat is lower in obese women with PWS than in those with essential obesity. Surrogate markers of CMD are, however, mostly similar in the two groups.
Racial differences in sexual dimorphism as an explanation for differences in olympic field and track achievement. Edward Dutton. It is argued that gender-contingent differences in the racial profile of Olympic track and field medalists between and is best explained by race-based differences in sexual dimorphism.
Alternative hypotheses for the data are examined but found wanting. Future research into these hypotheses is recommended. Ethnic differences in achievement in Darts. Data is presented about the ethnic composition of high level darts players. It is noted that the male players are overwhelmingly European and British and that British ethnic minorities are absent among top male darts players.
It is shown that this is predicted by the dominant European body type. High level female darts players are slightly more ethnically diverse. This is predicted by racebased differences in sexual dimorphism. Though it is argued that culture plays a part in explaining these data, purely cultural explanations are shown not to be persuasive.
Contest Competition in Men. Finally, we explore how contests may have contributed to male mating and reproductive success over human evolution.
The Environmental Security Hypothesis ESH proposes that when the environment is less secure, people will show greater preference for mates with survival-promoting traits Pettijohn and Jungeberg in Personality and Social Psychology Bulletin, 30 9 , —, In this study, we manipulated perceived environmental security and measured preference for different body and face characteristics as well as attitudes toward long-term LTM and short-term mating STM strategies.
Participants then completed a measure of sociosexual orientation and selected the three opposite-sex face and body types that they found most attractive from image matrices depicting physical characteristics varying systematically across body and face shape.
Female bodies varied in body fat and waist-to-hip ratio, and male bodies varied in muscle mass and waist-to-chest ratio. Face stimuli varied in masculine—feminine facial shape and masculine—feminine facial coloration.
Results indicated that, compared to controls, men in the environmental-threat condition showed a preference for higher body fat, and women in the environmental-threat condition showed a preference for higher muscle mass and more masculine faces. In line with the ESH, our findings predominantly support a context-specific pattern of mate preference and sexual strategies.
Bioelectrical impedance vector reference values for assessing body composition in a Spanish child and adolescent population. Feb Am J Hum Biol. Objectives: Reference values of the bioelectrical impedance vector for the Spanish child and adolescent population are needed for assessing body composition and hydration status in this population. Methods: This was a cross-sectional descriptive study conducted in Spanish healthy children and adolescents aged years boys and girls.
Resistance and reactance were measured with a single-frequency impedance analyzer at 50 kHz tetrapolar analysis. The values of resistance and reactance normalized by height were used to plot the bivariate 50th, 75th, and 95th percentiles of the population by age group. Results: Tolerance ellipses were drawn for the Spanish child and adolescent population studied.
The mean impedance vector showed displacement across all age groups except for 1 girls aged years, 2 girls aged years, and 3 boys aged years. There were sex-related differences in the mean impedance vector in all age ranges, even in prepubertal children.
Among adolescents, the patterns of the vector displacement were consistent with the timing of normal growth and development in all groups and are attributable to the maturation process. Conclusions: New tolerance ellipses have been constructed for Spanish children and adolescents by sex and age. These ellipses reflect the timing of normal childhood growth and development. Body composition and susceptibility to Type 2 Diabetes: an evolutionary perspective. Mar Type 2 diabetes is rapidly increasing in prevalence worldwide, in concert with epidemics of obesity and sedentary behavior that are themselves tracking economic development.
Within this broad pattern, susceptibility to diabetes varies substantially in association with ethnicity and nutritional exposures through the life-course. An evolutionary perspective may help understand why humans are so prone to this condition in modern environments, and why this risk is unequally distributed. A simple conceptual model treats diabetes risk as the function of two interacting traits, namely 'metabolic capacity' which promotes glucose homeostasis, and 'metabolic load' which challenges glucose homoeostasis.
This conceptual model helps understand how long-term and more recent trends in body composition can be considered to have shaped variability in diabetes risk. Hominin evolution appears to have continued a broader trend evident in primates, towards lower levels of muscularity. In addition, hominins developed higher levels of body fatness, especially in females in relative terms. These traits most likely evolved as part of a broader reorganization of human life history traits in response to growing levels of ecological instability, enabling both survival during tough periods and reproduction during bountiful periods.
Since the emergence of Homo sapiens, populations have diverged in body composition in association with geographical setting and local ecological stresses. These long-term trends in both metabolic capacity and adiposity help explain the overall susceptibility of humans to diabetes in ways that are similar to, and exacerbated by, the effects of nutritional exposures during the life-course. European Journal of Clinical Nutrition advance online publication, 29 March ; doi May Am J Phys Anthropol.
Meghan K. Objectives: Life history trade-offs may manifest between competing organs and tissues in the body. Discussion: These results indicate sex-specific life history strategies wherein the direction and timing of energy investment in girths varies between the sexes. Household-level financial uncertainty could be the primary driver of the global obesity epidemic.
Obesity is not just elevated adiposity, it is also a state of metabolic perturbation. Nettle et al. I suggest that the association of food insecurity with obesity in women from industrialized settings is most likely due to reverse causation: Poverty reduces agency to resist obesogenic foods, and this scenario is compounded by perturbations of insulin metabolism stemming from high adiposity and lipogenic diets.
Morphological signatures of high-altitude adaptations in the Andean archaeological record: Distinguishing developmental plasticity and natural selection. Karen J Weinstein. High-altitude hypoxia is one of many environmental stressors affecting human populations in the highland Andes. Living highland Andeans show adaptive physiological responses to these conditions through both developmental plasticity and natural selection.
Given the longevity of human settlement in this region, these same responses ought to have affected ancient Andeans. This paper tests whether developmental plasticity or natural selection best explains the morphological signatures of adaptations to high-altitude hypoxia in ancient highland Andeans.
I compare four groups of skeletons: two groups from lowland regions and two groups from high elevations. Previous work shows that the two highland groups have small bodies and voluminous ribs compared with the lowland groups indicating morphological adaptations to high-altitude environments.
This paper compares patterns of intrinsic variation and sexual dimorphism in body size, limb lengths, and rib morphology in highland and lowland groups to test if developmental plasticity or natural selection underlies these morphological differences.
The four groups share similar patterns of sexual dimorphism and intrinsic variation in body size and limb lengths. The two highland samples show greater degrees of sexual dimorphism in rib morphology than the lowlanders. Patterns of intrinsic variation in rib morphology do not sort by altitude.
Both natural selection and developmental plasticity in response to high-altitude hypoxia likely shaped skeletal morphology in ancient highland Andeans. Relationship between body mass, lean mass, fat mass, and limb bone cross-sectional geometry: Implications for estimating body mass and physique from the skeleton. Objectives: Estimating body mass from skeletal dimensions is widely practiced, but methods for estimating its components lean and fat mass are poorly developed.
The ability to estimate these characteristics would offer new insights into the evolution of body composition and its variation relative to past and present health. This study investigates the potential of long bone cross-sectional properties as predictors of body, lean, and fat mass.
Body composition was estimated from bioimpedance analysis. Results: Lean mass correlated most strongly with both upper and lower limb bone properties r values up to 0. Discussion: Lean mass can be predicted more reliably than body mass from limb bone cross-sectional properties. The results highlight the potential for studying evolutionary trends in lean mass from skeletal remains, and have implications for understanding the relationship between bone morphology and body mass or composition.
Stature and the Neolithic transition— Skeletal evidence from southern Sweden. Feb JASR. Human stature is a variable often used to study health changes in present and past populations. In this study possible differences in stature from the late Mesolithic-Early Bronze Age, based on skeletal data from southern Sweden, are investigated. Sex was assessed primarily using criteria on the pelvis and secondarily through statistical testing of sexual dimorphism.
Measurements of the vertical diameter of the femoral head, femoral anterior-posterior and medial-lateral were evaluated using an iterative discriminant analysis. Results confirm a significant difference in femoral length between archaeological culture groups for both sexes. Only a minor increase in male stature associated with the transition to agriculture could be noticed; stature then remained constant until the Pitted Ware Culture.
There was no change in female stature following the Neolithic transition. Female stature then increased gradually throughout the Neolithic, but decreased somewhat in the later part of the Late Neolithic-Early Bronze Age.
These findings suggest that the transition to agriculture did not affect health in any profound way, and that the high stature in the BAC-Early Bronze Age are dependent on a mix of genetic influx, population increase and good nutrition and health, possibly linked to an intensification and consolidation of the agro-pastoral economy.
Objectives Estimating body mass from skeletal dimensions is widely practiced, but methods for estimating its components lean and fat mass are poorly developed. Results Lean mass correlated most strongly with both upper and lower limb bone properties r values up to 0.
Non-bodily traits ranging from housing and vehicles through art to social media can, however, influence sexual selection even in absence of the phenotype proper. The theoretical framework of human sexual selection is updated in this article by unifying four theoretical approaches and conceptualizing non-bodily traits as extended phenotypic traits.
Methods: Existing research is synthesized with extended phenotype theory, life history theory, and behavioral ecology. To test population-level hypotheses arising from the review, ecological and demographic data on countries are analyzed with multiple linear regression modelling.
Conclusions: The evolutionary pathways of extended phenotypes frequently undergo a categorical broadening from providing functional benefits to carrying signalling value.
Extended phenotypes require investments in skills and bioenergetic resources, but they can improve survival in high latitudes, facilitate the extraction of resources from the environment, and substantially influence sexual selection outcomes. Bioenergetic investments in extended phenotypes create individual- and population-level tradeoffs with competing life history processes, exemplified here as a global tradeoff between adolescent fertility and economic complexity.
The merits of the present model include a more systematic classification of sexual traits, a clearer articulation of their evolutionary-developmental hierarchy, and an analysis of ecological, genetic, and psychological mechanisms that modulate the flow of energy into extended phenotypes and cultural innovations.
Adiposity in children and adolescents: Correlates and clinical consequences of fat stored in specific body depots. The Pennington Biomedical Research Center's Scientific Symposium focused on adiposity in children and adolescents. The symposium was attended by 15 speakers and other invited experts. The specific objectives of the symposium were to i integrate the latest published and unpublished findings on the laboratory and clinical assessment of depot-specific adiposity in children and adolescents, ii understand the variation in depot-specific adiposity and related health outcomes associated with age, sex, maturation, ethnicity and other factors and iii identify opportunities for incorporating new markers of abdominal obesity into clinical practice guidelines for obesity in children and adolescents.
This symposium provided an overview of important new advances in the field and identified directions for future research. The long-term goal of the symposium is to aid in the early identification of children and adolescents who are at increased health risk because of obesity and obesity-related conditions. Show more. Ecogeographical associations between climate and human body composition: Analyses based on anthropometry and skinfolds.
Feb Am J Phys Anthropol. In the 19th century, two "ecogeographical rules" were proposed hypothesizing associations of climate with mammalian body size and proportions. Data on human body weight and relative leg length support these rules; however, it is unknown whether such associations are attributable to lean tissue the heat-producing component or fat energy stores. Data on weight, height, and two skinfold thickness were obtained from the literature for nonindustrialized populations, providing male and female individual samples.
A variety of indices of adiposity and lean mass were analyzed. Preliminary analyses indicated secular increases in skinfolds in men but not women, and associations of age and height with lean mass in both sexes. Decreasing annual temperature was associated with increasing body mass index BMI , and increasing triceps but not subscapular skinfold.
After adjusting for skinfolds, decreasing temperature remained associated with increasing BMI. These results indicate that colder environments favor both greater peripheral energy stores, and greater lean mass. Contrasting results for triceps and subscapular skinfolds might be due to adaptive strategies either constraining central adiposity in cold environments to reduce cardiovascular risk, or favoring central adiposity in warmer environments to maintain energetic support of the immune system.
Polynesian populations were analyzed separately and contradicted all of the climate trends, indicating support for the hypothesis that they are cold-adapted despite occupying a tropical region. It is unclear whether such associations emerge through natural selection or through trans-generational and life-course plasticity. These findings nevertheless aid understanding of the wide variability in human physique and adiposity.
We calculated these indices in a reference population of healthy young men and in 32 nonobese young men from the Minnesota Study before, during, and after experimental semistarvation. What does gender dimorphism in stature tell us about discrimination in rural India, ?
Aravinda Meera Guntupalli. In the debate on gender discrimination in India a frequently used measure is sex ratio. We propose a new indicator: dimorphism in the nutritional and health status approximated by mean stature which reflects the burden of workload, and differential access to food and health, that surviving boys and girls have faced during their period of growth.
The analysis is based on the nutrition surveys carried out by the National Nutrition Monitoring Board NNMB , which is a rare source of comprehensive height data for both males and females. After controlling for biases due to changes in sampling design, we assess the development of dimorphism in stature for seven Indian states in the period The secular trends in gender dimorphism vary greatly from state to state. Finally, we explore the impact of several economic variables like agricultural output, poverty, real wages, development expenditures and the impact of monsoon rainfall on height dimorphism.
The regression analysis confirms that gender discrimination is increasing with poverty. The decreasing effect of real wages, state development expenditures and food supply are the new insights. Hundreds of variants clustered in genomic loci and biological pathways affect human height. Hana Lango Allen. Most common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype.
Genome-wide association GWA studies have identified more than variants associated with human traits, but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using , individuals, we show that hundreds of genetic variants, in at least loci, influence adult height, a highly heritable and classic polygenic trait. The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits.
Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified.
Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways.
Adaptive strategics of human populations under nutritional stress; in Watts E. Et al eds : Biosocial Interrelations in Population Adaptations.
The Hague. The Climates of the Continents. Sep Man. Patterns of Human Growth. Sex differences in morphological predictors of sexual behavior: Shoulder to hip and waist to hip ratios. Susan M. Hughes Gordon G. Gallup Jr. Differences exist between males and females in fat distribution, skeletal morphology, muscle mass, and body shape.
We investigated sex differences in shoulder to hip ratios SHR and waist to hip ratios WHR , and their relationships to different features of sexual behavior. Males with high SHR and females with low WHR reported sexual intercourse at an earlier age, more sexual partners, more extra-pair copulations EPC , and having engaged in more instances of intercourse with people who were involved in another relationship i.
The predictive value of these morphological features was highly sex-specific. The negative secular trend. Phillip V. In the following paper the concept of secular trend is discussed.
It is argued that secular processes should always be specified as to their direction. Such specification is not given in any of the current publications in which the term has been applied to changes in stature. A number of environmental causative factors are proposed, which can explain the historical development of the secular trend and the observed changes in its direction on a world-wide scale.
Charles R. In the current resurgence of interest in the biological basis of animal behavior and social organization, the ideas and questions pursued by Charles Darwin remain fresh and insightful.
This edition is a facsimile reprint of the first printing of the first edition , not previously available in paperback. The work is divided into two parts. Part One marshals behavioral and morphological evidence to argue that humans evolved from other animals. Darwin shoes that human mental and emotional capacities, far from making human beings unique, are evidence of an animal origin and evolutionary development.
Part Two is an extended discussion of the differences between the sexes of many species and how they arose as a result of selection. Here Darwin lays the foundation for much contemporary research by arguing that many characteristics of animals have evolved not in response to the selective pressures exerted by their physical and biological environment, but rather to confer an advantage in sexual competition. These two themes are drawn together in two final chapters on the role of sexual selection in humans.
In their Introduction, Professors Bonner and May discuss the place of The Descent in its own time and relation to current work in biology and other disciplines. Costs and benefits of fat-free muscle mass in men: Relationship to mating success, dietary requirements, and native immunity. William D. Potential benefits of greater male muscle mass include increased mating opportunities, while potential costs include increased dietary requirements and decreased immune function.
On the cost side, FFM and LMV are strong positive predictors of daily energy intake and strong negative predictors of C-reactive protein and white blood cell count, measures of native immunity. E Seeman. Sympercents: symmetric percentage differences on the loge scale simplify the presentation of log transformed data. Nov Stat Med. The results of analyses on log transformed data are usually back-transformed and interpreted on the original scale. Yet if natural logs are used this is not necessary — the log scale can be interpreted as it stands.
A difference of natural logs corresponds to a fractional difference on the original scale. The agreement is exact if the fractional difference is based on the logarithmic mean. Several simple clinical examples show that the loge scale is the natural scale on which to express percentage differences.
Sympercents should improve the presentation of log transformed data and lead to a wider understanding of the natural log transformation. Climates of northern and eastern Asia. A cross-cultural comparison of ratings of perceived fecundity and sexual attractiveness as a function of body weight and waist-to-hip ratio. May Psychol Health Med. This study attempted a cross-cultural test of Singh's a,b; theory of the relationship of waist-to-hip ratio WHR on judgements of female attractiveness using the stimulus figures designed by Tassinary and Hansen One hundred British half male, half female and Kenyan half male, half female young people rated 18 two-dimensional line drawings of a female figure varying in weight light vs.
Results showed the ratings factored into two dimensions relating to fecundity and sexual attractiveness. As before participants rated the WHR of 0. Light figures were judged more attractive than heavy, particularly by the British. An interaction showed that Kenyans thought light figures more fecund than heavy figures whereas it was the opposite pattern for the British. Implications of the cross-cultural differences are noted. Climates of Southern and Western Asia.
The abstract for this document is available on CSA Illumina. To view the Abstract, click the Abstract button above the document title.
Mar Evolution. Russell Lande. The evolution of sexual dimorphism in quantitative characters under natural and sexual selection acting differently on the sexes is analyzed using population genetics models.
The effects of genes when in males may be correlated with their effects when in females, producing correlated selective responses between the sexes, so that male and female phenotypes cannot evolve independently But under weak natural selection with constant relative fitnesses, in the absence of sexual selection, the joint evolution of the mean phenotypes of the sexes increases the mean fitness in a population, and if there is genetic variation for sexual dimorphism each sex eventually achieves a locally optimum phenotype.
With sexual selection, fitnesses are generally frequency-dependent and evolution of the mean phenotypes does not maximize the mean fitness. Provided individual fitnesses exist, at equilibrium natural and sexual selection balance in each sex.
A moderate intensity of sexual selection acting on a character under weak natural selection toward an intermediate optimum phenotype can produce a large deviation of the mean phenotype from the optimum and a substantial decrease of the mean fitness in a population, increasing the probability of extinction.
When homologous characters in males and females vary similarly and are highly correlated genetically, the rate of evolution of sexual dimorphism may be one or more orders of magnitude slower than that for the average phenotype in a population. Methods for partitioning sexual dimorphism into contributions from natural and sexual selection are discussed, and genetic experiments are suggested for testing the involvement of non-equilibrium correlated selective responses between the sexes in observed cases of sexual dimorphism.
Introduction 2. Human fatness in broad context 3. The proximate causes of fat deposition 4. The ontogenetic development of adiposity 5. The life-course induction of adiposity 6. The fitness value of fat 7. The evolutionary biology of adipose tissue 8.
Adiposity in hominid evolution 9. Adiposity in human evolution The evolution of obesity. Prediction of body fat in an Inuit community. Jan Am J Hum Biol. A Rode. The age- and sex-specific generic predictions of body density, and thus body fat content, as obtained by the skinfold equations of Durnin and Womersley , Br J Nutr —97 have been compared with direct hydrostatic estimates of body density in a sample of 51 moderately acculturated Canadian Inuit men, ages 18—36 years.
Specific rather than generic equations would seem necessary for the accurate prediction of body fat content from skinfold readings in the Inuit, although continuing acculturation to a sedentary lifestyle currently hampers the development of generalizable equations for this population.
Jan Am J Phys Anthropol. Hominids—both living and past—exhibit considerable variation in body size and shape. Both theoretical considerations and empirical observations indicate that some of this variation may be attributable to climatic adaptation. Consideration of potential climatic influences on morphology has important ramifications for reconstructing body form and behavior of past hominids, interpreting geographic and temporal variability and migrational events, explaining the origins and perfection of hominid bipedalism, and better understanding changes in brain size and encephalization during hominid evolution.
Life History Theory and Evolutionary Anthropology. Life-history theory has been developed in biology to explain the variation in timing of fertility, growth, developmental rates, and death of living organisms, as well as events directly tied to these parameters. The theory is useful in explaining variations in age-specific human fertility and mortality patterns, as well as understanding how the human life course evolved to patterns so divergent from those that characterize our close primate relatives.
Surprisingly, this same theory can also be used to explain why people often ignore the long-term consequences of behaviors that produce short-term gain. Oct Body weight, waist-to-hip ratio, breasts, and hips: Role in judgments of female attractiveness and desirability for relationships.
Devendra Singh Robert K. Morphological features such as overall body fat, body fat distribution, as measured by waist-to-hip ratio, breast size, and hip width have been proposed to influence female attractiveness and desirability. To determine how the variations of these morphological features interact and affect the judgment of female age, attractiveness, and desirability for romantic relationships, two studies were conducted.
In Study 1, college-age men rated female figures differing in body weight, waist-to-hip ratio, and breast size for age, attractiveness, health, and desirability for short-and long-term relationships. Female figures with slender bodies, low waist-to-hip ratios, and large brasts were rated as most attractive, feminine looking, healthy, and desirable for casual and long-term romantic relationships.
In Study 2, female figures with similar body weight and waist-to-hip ratios but differing hip widths and breast sizes were rated for the same attributes as in Study 1. Female figures with large breasts and narrow hips were rated as most youthful, attractive, and desirable for casual and long-term romantic relationships. It seems that larger body size, a high waist-to-hip ratio, and larger hips make the female figure appear older, unattractive, and less desirable for engaging in romantic relationships.
Discussion focuses on the functional significance of interactions among various morphological features in determining female attractiveness. Jul Pediatr Res. LBW increases the risk of a number of noncommunicable diseases in adulthood.
However, birth weight BW cannot describe variability in infant body composition BC. Variability in fat mass FM and fat-free mass FFM at birth may be particularly important in low-income countries because they undergo nutritional transition. There is a need for data on birth BC and its predictors from low-income countries in transition. Female gender and being an infant of primi- or secundiparous mothers predicted lower BW and lower birth FFM but not FM, compared with male gender and infants of multiparous mothers, respectively.
There was a positive linear relationship between BW and relative amount of FM for boys and girls. This study presents reference data on birth FM and FFM from a low-income setting and provides background for further longitudinal mapping of the relationship between fetal BC, childhood growth, and adult disease. Aging and reproduction have been independently associated with body shape in women, with redistribution of body fat from lower to upper body regions.
This may be interpreted as a life history strategy for allocating energy between competing peripheral fat depots for reproduction, and central fat depots for maintenance and survival. It remains unclear whether men show similar life history strategy in shape. The objectives of this study were to investigate associations between shape, age, and number of offspring in both men and women from Thailand. We analyzed data on body shape from three-dimensional photonic scanning, and number of reported offspring, available for 5, men and 6, women aged years from the Thai National Sizing Survey.
Bearing children was associated with increased upper body girths and decreased lower body girths in women, independent of age, weight and height. Unlike motherhood, fatherhood was not associated with shape outcomes indexing adiposity, but was associated with arm girth, which may represent an index of sexual attractiveness. In those without children, aging was associated with greater upper body girths and reduced lower body girths, in both sexes. Life history strategy in body shape is apparent in both sexes, with aging associated with a shift of tissue away from the lower limb to the upper body.
Such strategy may reflect age-changes in the relative costs and benefits of different regional tissue masses. Changes in fat distribution related to aging and reproduction may contribute to the life-course development of cardiovascular risk.
The evolution of sexual dimorphism in animals: Hypotheses and tests. Three major hypotheses, based upon mechanisms of sexual selection, intersexual food competition and reproductive role division, have been advanced to explain the evolution of sexual dimorphism in body size and morphology of animals.
Genetic models suggest that all of the hypotheses are plausible, and empirical studies demonstrate that each of the three mechanisms operates in natural populations. However, problems arise in testing hypotheses for the evolution of sexual dimorphism: more than one mechanism may be operating simultaneously, and the demonstrated occurrence of a mechanism does not indicate that it actually results in selection for dimorphism.
A recent statistical technique offers a solution to these problems and provides a promising new approach to the study of sexual dimorphism, in which researchers can assess the relative importance of each mechanism in present-day selection for sexual dimorphism within a species. Sep Nature. Genome-wide studies have identified several common genetic variants that are robustly associated with adult obesity risk.
Exploration of these genotype associations in children may provide insights into the timing of weight changes leading to adult obesity. Early infancy was defined as birth to age 6 weeks, and early infancy failure to thrive was defined as weight gain between below the 5th centile, adjusted for birth weight.
The obesity-risk-allele score showed little association with birth weight regression coefficient: 0. The obesity-risk-allele score was also positively associated with early infancy length gain 0. The use of robust genetic markers identified greater early infancy gains in weight and length as being on the pathway to adult obesity risk in a contemporary birth cohort.
Jul Am J Hum Biol. Both aging and reproduction have been shown to influence female body shape in industrialized populations, involving redistribution of fat from lower to upper body regions. However, the extent to which effects of parity vary by age and the extent to which age affects shape independent of parity remain unclear. We studied shape variability in relation to age and parity in a cross-sectional survey of 4, white British women, using three-dimensional photonic scanning.
Our data support previous findings of "covert maternal depletion" in relation to parity, but show that this is merely a more pronounced component of a general strategic shift of fat from lower to upper body with age. These findings are consistent with a life-history model of female energy stores being allocated to competing "reproduction" and "maintenance" depots, with the optimal trade-off strategy changing with age and with that strategic shift accelerated by bearing children.
This model is relevant to the "grandmother hypothesis. Dec Man. May Horm Res. Joel N. Hirschhorn Guillaume Lettre. Recent advances in genetics and genomics now permit comprehensive genome-wide surveys of common genetic variations in those variants that are associated with stature.
The first such studies have borne fruit, identifying over 40 genetic loci that can be reproducibly shown to have an influence on adult height. These unbiased searches throughout the genome identified several loci that also harbour rare mutations responsible for more severe alterations in height or skeletal growth. Although the predictive value of the common variants thus far discovered remains low, the identification of these loci has led to new insights into the biology of human growth, and may help identify genes that underlie previously uncharacterized syndromes of abnormal skeletal growth.
Latitudinal patterns in human stature and sexual stature dimorphism. Jan Ann Hum Biol. Anders Gustafsson. There exists substantial variation in human stature and sexual stature dimorphism that has been attributed to both genetic and environmental variables. A few studies have previously investigated possible relationships between latitude and stature, building on the idea that variation in climate can influence body size Bergmann's rule. This change in body size can in turn have influenced sexual stature dimorphism in accordance with Rensch's rule.
Phylogenetic and non-phylogenetic analyses were conducted on a cross-cultural sample of human populations. The results indicate that both male and female mean stature increase with increasing distance from the equator. While sexual stature dimorphism also was positively related to latitude in the non-phylogenetic test, this relationship disappeared when using a phylogenetic comparative method.
Evidence was also found for curved relationships between latitude and both male and female stature, as well as stature dimorphism, all indicating a maximum at around 40 degrees from the equator. The results of the present study indicate that both male and female stature are weakly associated with latitude. It is possible that these relationships are evolved responses to variation in climate.
No unequivocal conclusion could be drawn regarding a possible relationship between latitude and sexual stature dimorphism.
Katherine Ralls. Females are larger than males in more species of mammals than is generally supposed. A provisional list of the mammalian cases is provided. The phenomenon is not correlated with an unusually large degree of male parental investment, polyandry, greater aggressiveness in females than in males, greater development of weapons in females, female dominance, or matriarchy.
The phenomenon may have evolved in a variety of ways, but it is rarely, if ever, the result of sexual selection acting upon the female sex. The most common selective pressures favoring large size in female mammals are probably those associated with the fact that a big mother is often a better mother and those resulting from more intense competintion among females for some resource than among males.
It appears that, in general, more than one such pressure must affect the females of a species, and that their combined effects must not be countered by even stronger selective pressures favoring large size in males, before the result is that of larger size in the female sex. Sexual selection may often be operating upon the male sux in mammals even when it is smaller.
Present knowledge about the species of mammals in which females are lager than males is quite rudimentary. Much more information is needed before we will be able to speak of the selective pressures accounting for the phenomenon with any reasomable degree of certainty. Perhaps the most fruitful approach would be a series of field studies of groups of related species in which females are larger in some species and males are larger in others.
The correlations between anthropobiological and climatic variables in Sub-Saharan Africa: Revised estimates. Jan Hum Biol. J Hiernaux. The coefficients of correlation between 30 anthropobiological and 5 climatic variables were recomputed in data from sub-Saharan African populations. The coefficients suggest that the M, O, Ro and r alleles are probably independent of climate in sub-Saharan Africa.
An explanation of the apparent association of B, R1 and R2 frequencies with climate is proposed in terms of a sensitivity of lethal agents or of their intermediary hosts to climate, by analogy with the Hb s case.
Fingerprint patterns and some metric variables, like head length, were found to be independent of climate. The relevance of Bergmann's rule in the interpretation of body measurement from sub-Saharan Africa is discussed. Height-normalized indices of the body's fat-free mass and fat mass: potentially useful indicators of nutritional status.
Am J Clin Nutr 52, Body mass index and body energy stores in developing countries. N G Norgan. Body mass index BMI is used widely as an index of fatness the proportion of the body as fat but its application to the low weight and stature populations in developing countries has not been established.
As BMI is an indicator of size the amounts of fat and fat free masses as well as fatness, its relation to fatness and interpretation as a measure of energy stores may vary in different groups. Very low BMI reflects low fat and fat free mass, a state for greater concern than low fat mass alone, and possibly more typical of chronic energy deficiency. Can sexual dimorphism evolve because of ecological differences between the sexes?
Although several examples of this phenomenon are well known from studies on birds, the idea has often been dismissed as lacking general applicability. This dismissal does not stem from contradictory data so much as from the difficulties inherent in testing the hypothesis, and its apparent lack of parsimony, in comparison to the alternative explanation of sexual selection. The only unequivocal evidence for the evolution of sexual dimorphism through intersexual niche partitioning would be disproportionate dimorphism in trophic structures e.
This criterion offers a minimum estimate of the importance of ecological causes for dimorphism, because it may fail to identify most cases. A review of published literature reveals examples of sexually dimorphic trophic structures in most animal phyla. Many of these examples seem to be attributable to sexual selection, but others reflect adaptations for niche divergence between the sexes. For example, dwarf non-feeding males without functional mouthparts have evolved independently in many taxa.
In other cases, males and females differ in trophic structures apparently because of differences in diets. Such divergence may often reflect specific nutritional requirements for reproduction in females, or extreme sexually selected? Ecological competition between the sexes may be responsible for intersexual niche divergence in some cases, but the independent evolution of foraging specializations by each sex may be of more general importance. If ecological causation for dimorphism can be demonstrated in so many cases, despite the inadequacies of the available criteria, the degree of sexual size dimorphism in many other animal species may well also have been influenced by ecological factors.
Hence, it may be premature to dismiss this hypothesis, despite the difficulty of testing it. Estimation of body fat in healthy Swedish women during pregnancy and lactation.
Reliable estimates of changes in body fat are important in studies of energy requirements during human reproduction. It is not known if current methods for the estimation of total body fat TBF are adequate for this purpose. In this paper earlier reported data from 29 women are used to show how methodology affects estimates of changes in TBF during reproduction.
Skinfold thicknesses are also reported and equations relating these measurements to TBF were developed and used to demonstrate how well the skinfold technique could estimate such changes.
No correlation was found between changes in body weight and body fat during early pregnancy or between the maternal changes in body weight and body fat over the complete pregnancy. These findings are tentatively explained by changes in the degree of hydration of the body. An Anthropological Perspective of Obesity.
So, Alice and Bob are making the beast with two backs, so to speak. Except it's more of a beast with three backs. Sdx or without them being aware of it, a third party is actively enjoying their encounter, and not in the usual wayeither.
If a body snatching leads to sex with the body's original owner left unaware, then prxies Not Proxies in the Bednot this trope. This tends to be a magic trope, although sci-fi versions exist sx well. Often an upgrade of Dirty Mind-Reading.
It's a Fetishobviously, and a subtrope of Power Perversion Potential. Community Showcase More. Follow TV Tropes. You need to login to do this. Get Known if you don't have an account. This trope is when: Someone is telepathically or otherwise linked to the characters, and can feel whatever they're feeling; Someone is participating in the rompin', but isn't physically there; Advertisement:.
In the Ghost in the Shell manga, Motoko, Kurutan, sex Ran all experiment with a new pornographic software that they're developing that allows the users to feel what everyone else is feeling. Batou is given the task of interrupting her "shore leave", and shortly after he hacks his way in, he starts to feel icky because his male cyborg body and brain didn't have the receptors needed to process what a female orgasm feels like.
It didn't help any that he also got infected with the cyberdrug they were using at the time either. In Petshop Of HorrorsLeon is seduced by proxoes different women in one sed. It turns out that they're plant spirits who were using him to spread their proxies from one girl to another. In Chapter of Ah! My GoddessBelldandy and Keiichi are overshadowing another goddess and mortal who fell in love.
Judging by the the last panel on page 23, the past couple were lovers. Which means Bell and Kei are lovers, by proxy.
Comic Sex. In ElfQuestwhen Cutter realizes that Zhantee has always been in love with Leetah from afar, he mentally shares his memories of his relationship with Leetah with Zhantee as a gift — including their romantic intimacy. In Requiem Vampire Knightthere is a character capable of proxies orgasms from others as they are about to happen.
This seems to be at least a significant chunk of the principle behind the Shrieky Girls of Doktor Sleepless. Proies was a comic about a horny ghost that ran in the Australian edition of Penthouse. In one strip, he manipulated two women into having sex and joined in without either of them noticing. Due to being in tune with Haruhi's emotions at all times, especially if the emotions are particularly strong, Koizumi ends up extremely flushed when Haruhi and Kyon are making out. Multiple Firefly fanfics have explored the implications of River's long-established Power Incontinence while stuck aboard a very small spaceship with her big brother right after he finally scores with Kaylee.
In Red vs. BlueAIs are able to possess others by entering the AI slot in their armor, often leaving the possessee still conscious. Fanfic takes this proxkes its logical conclusion with Power Perversion Potential.
Films — Live-Action. Although it's more of a PG-rated Makeout by Proxy. She doesn't care all that much for Malkovich — she just gets off on "Lotte in Malkovich". Malkovich slowly becomes aware of what's going on. Things get out of hand. In Freaksone of the conjoined twins is shown to get aroused when her sister is kissing her boyfriend. Since the sister and boyfriend proceed to get married and have sex, one can assume the trope is in full effect.
Strange Days involves illegal devices which can record and play back memories — giving the user all of the sensory input felt by whoever was being recorded. The recording include sex, of proxies parts of a couple of raunchy memory proxies are shown, both for sale and for personal use. It's probably a huge part of the market. Brainstorm also features a memory-recording device, and one prpxies the scientists working on it uses it to make a porno.
In Surrogates some people willingly let others access their robotic avatars to feel the pleasure of living in a perfect body and touching it. She ends up paying them back for it oroxies using the psychic connection to target the Scimitar 's bridge with the Enterprise 's weapons. In the Unrated Edition of Pretty Coolthe woman investigating Howard uses a device to tap into his body while he has sex with his sister's friends in their hot tub.
Species II : The two proxiea hybrids are mind-linked, and also desperately want to hook up with each other to create purer offspring than they could with human mates. There are several times when Patrick is having sex somewhere else, and Eve goes into heat and apparently orgasms at the same time. Enter proxiea Void : The main character is killed about 15 minutes into the movie and spends the rest of it as a disembodied spirit.
There are numerous occasions where he observes people having sex and flies into their heads to experience eex from their point of view. In Robert A. In The Wheel of Timethe Warder bond allows people to feel what others do. So proxies Elayne and Rand finally have sex, Birgitte who is bonded to ElayneMin, and Aviendha who are bonded to Rand all have to go off and get drunk so they can't feel precisely what is going on.
Walter Jon Williams ' Aristoiwhich is set in a future where everybody has wireless internet connections in proxies heads, has a science-fictional swx. In the Dragonriders of Pern setting: Proxies mental link between dragons and riders proxiws cause this effect. Generally, when dragons mate, their riders are pulled into the lust and wind up following suit whether they sex to or not — but it proxies works in reverse, most notably in the case of Lord Jaxom, who winds up with a strange, white runt of a dragon.
Being apparently asexual, it has no interest in "flying" ;roxies female dragons, but it DOES seem to rather enjoy sharing Jaxom's feelings when HE'S proxes with a girl.
In Moreta: Dragonlady of PernMoreta's away from her queen, Orlith, on a time jump when she and Alessan resolve their ssex. As she's dozing off, Moreta thinks srx Sex would have liked Alessan's lovemaking, too. In the novel Geek Loveconjoined twins Elly and Iphy have sex with a man. Elly wants it, prxoies Iphy It gets even more squicky because the two share the same bottom half.
In The Dresden Files novel White Nightresident wizard gumshoe Harry and his apprentice Molly are trying to get an impression on the last moments of a woman who has mysteriously died. Because of Molly's talents with magical detection, she's the one who'd tasked peoxies picking out the dead girl's last sensations.
It turns out, her last moments were wrapped up in the lethal sexual ecstasy of a White Court vampireand Molly catches the full blast.
At proxise point in the Sword of Truth series, Nicci links herself to Kahlan and then lets a violent brute have sex with her, forcing Kahlan to feel every sensation as if she were the one getting it. In Commander-in-Chief by Nikolai Gudanets, a psychic alien squid mind-controls a call girl and arranges for her to be ordered by an American government official.
After taking control of him as well, the alien realizes that the man is still aroused, dex he has proxiez do it, while connected to both. This leads to a rather graphic scene in which the alien has trouble with pronouns due to being in both minds at the same time. It even experiences orgasm, a strange feeling for its species. The second time it happens turns deadly, when the official accidentally bites a hooker's sex during sex.
In the Heralds of Valdemar series, Talia has a permanent empathic link with her Companion that can't be blocked, even when her Companion is busy ptoxies the Companion mares sed a virile stallion he is. As The Empathshe's also treated to the emotions of her fellow Heralds whenever they're nearby unless she very carefully shields herself.
Being initially roomed next srx an exceptionally randy trainee, it is no surprise that she later chooses to move her permanent quarters to a remote tower of the Collegium. Animorphs doesn't give us all pfoxies details it is a kid's book, supposedlybut Oroxies One and one of her first human hosts did this with another human-Controller, resulting in a pair of twins with four "parents. In Marge Piercy's Woman on the Edge of Time, the main character travels to the future and has sex with someone she pfoxies there.
It's only after the fact that she learns that the mechanism behind her ssex travel which relies on a psychic bond sex her and another person proxirs the future, meant that said other person was aware of the sex as it was going on. As she was also in love with Kylar, sex enjoys it, but feels dirty as well as she views it as too voyeuristic. In the Lilith's Brood series, the Oankali are a three-gendered race, and proxies that manner of relationship when they mix with humans.
It roughlyly involves the ooloi being in-between the male and female and connecting their minds, so that they have sex mentally while never sex each other, only the ooloi conduit, and the ooloi enjoys all the feelings of both. In the Night Huntress wex, Vlad Tepesh has the rare ability to read humans' minds.
On proxiex occasion, he remarks on the shouts going off in his head even though Cat, the main character, and her husband were in a soundproof room. In narration: "Good God, I hadn't considered that. This must be what it felt like to have someone find a sex tape of you. Now the Horsemen are in new hosts, together, and the protagonist discovers that having been ridden leaves behind a psychic connection between host and Horseman.
This is particularly traumatic because prixies protagonist is neuterand thus has not had much experience with sex before this. At one poxies in The Rowanby Proixes McCaffreyproxies powerfully telepathic Rowan, while in the "can't keep her hands off him" early delirious stage of her first sexual relationship, has to be quietly told by one of her other housemates that she's "broadcasting".
The third and final round allows rape as a way to "ensure a finish". The serfs' memories are wiped of the game events. Among the many works of author Sex Laymonthe book Body Rides is about a man who is given a magic ring which allows him to astral project and inhabit someone else's body. They are unaware of his presence, but he experiences everything they do, including their thoughts. Naturally, this includes sex. Live-Action TV. On ProxieesRiver a telepath once walked proxirs as Wash and Zoe were making out in the cockpit.
She is able to feel what both of them are feeling and visibly reacts. When Phoebe developed her empathy powers in Proxiexshe became capable of feeling the emotions of people around her. This led to a fairly squick implication of this trope when she was walking with Piper proxles sister and a guy was checking Piper out. Upon beginning to feel his sex towards her own sister, Phoebe informed Piper of the fact, and the two decided to quickly move right along.
Telepaths in Babylon 5 already have problems keeping everyone else's thoughts outso guess what happens when two powerful telepaths get it on in the middle of a telepath colony.
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One with whom your sexual partner has had sexual relations with. all to him, my buddy Hans found out he has a dog for a sex proxy! Altered host plant volatiles are proxies for sex pheromones in the gall wasp Antistrophus rufus. John F. Tooker, Wilfried A. Koenig, and.
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We value your privacy. Download citation. Request full-text. A 'read' is counted each time someone views a publication summary such as proxies title, abstract, and list of authorsclicks on a figure, or views or downloads the full-text. Learn more. DOI: Jonathan CK Wells. Sexual dimorphism in human stature, physique, and adiposity is well established, but the ecological factors that account for its variability remain unknown.
This study aimed to describe population variability in body composition dimorphism, and to test whether annual temperature and proxies for population energy supply accounted for this variability. Data on sex-specific anthropometry weight, stature, triceps, and subscapular skinfolds prpxies mean annual temperature were collated for rpoxies nonindustrialized populations.
Lean mass and fat mass were calculated. Sexual dimorphism was expressed in sympercents. Sex-averaged skinfolds and stature were used as proxies for short-term and long-term energy supply, respectively. All outcomes showed significant mean dimorphism except body mass index. The magnitude of dimorphism was not randomly distributed across global regions, being lowest in African and Asian populations and greatest in Arctic populations.
There was a negative correlation across populations between lean mass dimorphism and adiposity dimorphism, independent of temperature. With sex temperature, dimorphism in both lean mass and adiposity increased. Dimorphism increased in fatter but not taller populations, independently of temperature. The inverse correlation between lean mass dimorphism and adiposity dimorphism indicates a sex-trade-off between these two tissue accretion strategies.
At colder temperatures, females invest disproportionately more in adiposity, and males disproportionately more in lean mass. Dimorphism also increased in proportion to proxies for short-term but not long-term energy availability.
Sex findings suggest that phenotypic plasticity contributes to variability in body composition dimorphism, and that the occupation of dimorphic niches regarding reproductive energetics may be important. Citations References Additionally, the dimensions of the calcaneus have also been correlated to body mass and have been used to demonstrate sexual dimorphism in modern populations Gualdi-Russo, For all elements, this sample appears to have a relatively even ptoxies of males and females, prodies to similar estimates using traditional methods of sex estimation for the os coxa Table 1 and Table 8.
Statistically significant differences ssex the sexes were found for sex metrics collected, yet most of these were ineffective for the prlxies of logistic regression formulae. Estimating sex using isolated appendicular skeletal elements from Chachapoyas, Peru.
The estimation of sex from human skeletal remains is one of the primary steps in the creation of a bioarchaeological demography. Conventionally, sex has been estimated from crania or os coxae, but commingled contexts pose challenges when associating these key elements with the rest of the remains becomes impossible or if the sample is mostly represented by postcranial appendicular elements.
Following successful applications of logistic regression to appendicular metrics in forensic anthropology for the estimation of sex using appropriate reference samples, this study aims to create a proxies method to be applied in archaeological contexts in the Andes. This is achieved through the collection of osteometric data from complete burials of previously estimated sex recovered at the archaeological site of Kuelap, in Chachapoyas, Peru.
Using these data, sex created sex regression formulae, using both frequentists and Bayesian approaches, that utilize standard metrics of the humerus, femur, and tibia to estimate the sex of individuals in this sample, testing their apparent accuracy and, through their application to a commingled context, their applicability in situations when only appendicular remains may be present or complete.
No significant difference was observed between the Bayesian approach and the frequentist approach. The application of this method for sex estimation to a commingled context also provided a demography consistent with that created using only os coxae and cranial remains. These results underscore the validity and reliability of this methodology and provide further support for its application in other bioarchaeological contexts across sex Proxes region.
Human growth and morphology are af- fected by genetics gene flow, drift, mutation, and mating practices Roberts, ;Holliday, and socioeconomic factors, such as nutritional intake, caloric output, and exposure to disease Ruff, ;Stinson, ; Wells, Analyzing postcranial morphology body proportions in past populations can provide valu- able information regarding how they interacted with their environment and neighbors such as health, activity levels, genetic admixture, migration, and cultural prac- tices.
Average body size and shape vary between different human popula- tions according to climatic environments found around the world and sub-populations i. Nov Due to its critical location on the Nile River controlling trade from the south, Tombos is an important ancient site to explore the interaction between Egyptians and Nubians.
To assess population continuity at Tombos through sociopolitical transitions, the appendicular skeleton of people from the New Kingdom and Napatan periods was examined.
Using morphometric and statistical analyses, body proportions on the upper and lower limbs were studied on each element through size i. The Napatan component when Proxies ruled Egypt was consistently larger in size than the earlier New Sex component when Egypt ruled Nubiawith little variation in shape. More variability in both size and shape was observed in males. When compared with other Nubians C-group and Kerma and Egyptians Middle and New Kingdom sx, the Tombos Napatan sample males and females was generally larger, whereas the Tombos New Kingdom sample was generally proxes than other Nubians and proxiea in size to Egyptians.
Some of the variability between the Tombos samples may be the result of gene flow, or rather changes in migration to the area through time and sociopolitics.
However, the numerous differences in size with few in shape, provide more support for an environmental explanation since size is more susceptible to nutritional stress, disease, and physical activity.
These results show that the people of Tombos underwent biological alterations during these major sociopolitical changes from Egyptian rule over Nubia during the New Kingdom to Nubia ruling Egypt during the Napatan period. This study also demonstrates morphometric analyses of multiple bones and measurements are an important supplement to other bioarchaeological analyses to provide a broader of view of physical changes that occur over time. This article is protected by copyright.
All rights reserved. Sexual dimorphism in human body size and composition is well established, and apparent in diverse populations. The most common explanation for such sex differences is sexual selection . This demonstrated difference in body form between men and women has not been studied from the point of view of weight loss.
Fat deposits are reduced in response to weight loss in both men and women [1, 8,20], but it proxies unclear whether there are anatomical regions which respond differently according to sex. This is part of the features sex sexual dimorphism, which manifest at birth, but become prroxies evident after puberty [1,20]. Fat deposits are reduced in response to weight loss in both men proxies women [1,8,20], but it is unclear whether there are anatomical regions which respond differently according to sex.
This is part of the features of sexual dimorphism, which manifest at birth, but become more evident after puberty [1, 20]. The baseline hormone concentrations of leptin, ghrelin, and adiponectin influence weight loss suc- cess in males and females. Influence of previous body mass index and sex on regional fat changes in a weight loss intervention.
Sep Objectives: Men and women may lose weight in a different fashion. This study compares the changes in different anatomical regions after a well-controlled weight loss program wex sex and initial BMI. Usually, the arms and legs are the regions that lose more weight in obese participants, but men lose the highest percentage of mass proxies the trunk. There were differences between men and women for the areas of left trunk mass gright trunk mass gtotal mass of the trunk gandroid mass gand finally in the total mass in overweight participants gwith higher values proxies men than for women.
The region that loses more weight and fat is the proxies, followed by the legs, and then the arms, when the loss is observed in function of the total weight or fat lost. Conclusion: Both BMI and sex exert a definite influence fat loss, especially in some anatomical regions. Humans with traditional subsistence level life-styles show far lower adiposity, but women are generally at least marginally fatter than men Abbie, ;Truswell and Hansen,suggesting that sexual dimorphism in fatness is an evolved trait peculiar to humans and is manifest under a range of environments Norgan, ;Pond, ;Wells, Wells,a.
He sidestepped the more conservative cause-namely, a far better food supply and lesser opportunity for exercise in the Oregon colony than in the Texas one. Similar explanations have been attempted to account for variations in the sexual dimorphism of fatness in human populations living at different latitudes, even though the relation between fatness and climate was inconsistent and cultural differences in exercise and diet were not well integrated in that study Wells, a.
Both diet and exercise are major contributors to variation in human fatness Stern,ssex well as to that among wild baboons Altmann et al. Nov Am J Phys Anthropol. There is a paucity of information on body composition and fat patterning in wild nonhuman primates.
Dissected adipose tissue from wild toque macaques Macaca sinica WTMfeeding on a natural diet, accounted for 2. This was far less than fatness reported for nonhuman primates raised in captivity or for contemporary humans. In WTM, fatness increased with age and diet richness, but did not differ by sex. In WTM none of which were proxles intra-abdominal fat filled first, and "excess" fat was stored peripherally in a ratio of about Intermuscular fat was minimal 0.
With increasing total adiposity, accumulating fat shifted in its distribution among eight different main internal and peripheral deposit areas-consistent with maintaining body balance and a low center of gravity. The available data suggest that, in arboreal primates, adaptations for agile locomotion and terminal branch feeding set constraints on the quantity and distribution of fat.
The absence of a higher percentage of body fat in females and neonates as are typical of humans suggests that arboreal adaptations preclude the development of fat-dependent, large-brained infants and the adipose-rich mothers needed to sustain them. The lifestyle and body composition of wild primates represent a more appropriate model proxies early human foragers than sex ;roxies monkeys do. Am Proxise Phys Anthropol, Furthermore, variability in both fat and lean mass is consistent with Bergman's hypothesis Wells, athough the associations vary subtly by sex Wells, c.
The notion that variability in human morphology indicates proxies adaptation is sufficiently well accepted that it is the primary lens through which broader hominin morphological variability is interpreted Ruff, ;Weaver, Increased investment in any one of these functions reduces the allocation of energy to the others, resulting in trade-offs between them Sex, Beyond Bergmann's rule: Global variability in human body composition is associated with annual average precipitation and annual temperature volatility.
Objectives: Human populations exhibit substantial geographical variability in body size and shape. However, pdoxies ecological stresses underlying this morphological variability remain poorly understood. The prevailing evolutionary explanation, "Bergmann's rule" assumes that morphological variability proxiew an adaptive response to average thermal conditions.
We hypothesized that other climate factors-annual average precipitation, a marker of ecological productivity and eex temperature volatility, a marker of infectious disease spikes-may also contribute to variability in body composition.
Materials and methods: We explored this proxiee by examining associations between these climate factors and geographic variability in body composition across male and female populations from nonindustrialized settings. We used monthly climate data over years to develop new climate indices for all worldwide land areas.
Tom Simmons. May an individual consent to sex in advance of incapacity or intoxication? Can an individual consent prospectively to intercourse? Should we sex recognize consent given contemporaneously sex the sexual act? These are straightforward questions which reside within core human needs and autonomy, yet few have considered them in the elder law context.
Consensual sex has been explicated by juries, lawmakers, and scholars with practically endless variations, but a temporal dimension to sexual consent has not. What about for sex? An individual facing dementia may want to continue to have sex with sex partner even after dementia has diminished or destroyed her capacity.
If prospective sexual consent is invalid, her partner would be guilty of rape for an act of penetration with proxies even if she had unambiguously extended pre-incapacity consent. Individuals may want to grant prospective consent to sex for different reasons. The questions posed by Boni-Saenz get at the basic concept of self. This kind of abstract problem sex interest some, but it can also be proxjes in concrete terms.
If the question is framed as an individual right, it is difficult — but not impossible — to argue that the right should be denied sex with advanced dementia, traumatic brain injuries, a stroke, or senility.
These kinds of questions, though, as difficult as they are, are actually more problematic than they might initially seem.
We tend to think of dementia or incapacity as a light switch, either on or off. In reality, a loss prodies capacity sex always appears in gradations of grey, not as either black or white.
Many individuals without capacity can articulate their desires. Moreover, sexual disinhibition is often undiminished by dementia. Proxids delivered a directive to her caregivers for the time when she would lose capacity. She wanted, she told them, to enjoy replays of her favorite television program, Gunsmoke. She was sure that this would give her comfort as she lost the proxies to articulate her wants. Inevitably, she proxies and lost capacity.
Her ssex dutifully played Gunsmoke for her, but the tapes were distracting, even distressing, to her. Closely-spaced television dialogue can become indecipherable and even terrifying to proxies with dementia. The same kind of quandary with proxids sexual advance directive is even more important — and disquieting. Next, Boni-Saenz injects another problem. Along with advance directives, healthcare proxies are among the most commonly utilized tools for elder law attorneys.
A healthcare proxy is a kind of durable power of attorney which appoints a surrogate decision maker over healthcare decisions. These instruments permit an agent, such proxies a trusted friend or family member, to grant — or withhold — informed consent sex various medical situations if the principal has lost capacity.
If sexual advance directives are permitted to prospectively grant or deny consent to physical intimacy, then, sex extension, sexual powers of attorney are also warranted. Vesting a trusted agent with the power to consent or refuse intimacy goes proxies toward ameliorating the inherent problem of an advance prpxies the difficulty of responding to unanticipated circumstances.
Spouses and children frequently fit the bill. Proxies envision a husband-agent making the decision on behalf of his incapacitated wife-principal about whether to consent to have sex with him. He will — as agents often do — wear two proxies. And what if an adult child is the agent? Picture a daughter faced with the decision of sexual consent on behalf of her aged mother. Your email address will not be published.
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