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Sample records for stabilizing sexual selection

  1. Phase Transitions in Sexual Populations Subject to Stabilizing Selection

    Science.gov (United States)

    Rogers, A.

    2003-04-01

    We show that a simple model of an evolving sexual population, which dates back to some of the earliest work in theoretical population genetics, exhibits an unexpected and previously unobserved phase transition between ordered and disordered states. This behavior is not present in populations evolving asexually without recombination and is thus important in any comparison of sexual and asexual populations. In order to calculate the details of the phase transition, we use techniques from statistical physics. We introduce the correlation of the population as the order parameter of the system and use maximum entropy inference to find the state of the population at any time.

  2. Proximity of signallers can maintain sexual signal variation under stabilizing selection

    NARCIS (Netherlands)

    van Wijk, M.; Heath, J.; Lievers, R.; Schal, C.; Groot, A.T.

    2017-01-01

    How sexual communication systems can evolve under stabilizing selection is still a paradox in evolutionary biology. In moths, females emit a species-specific sex pheromone, consisting of a blend of biochemically related components, to which males are attracted. Although males appear to exert strong

  3. Reduced genetic variance among high fitness individuals: inferring stabilizing selection on male sexual displays in Drosophila serrata.

    Science.gov (United States)

    Sztepanacz, Jacqueline L; Rundle, Howard D

    2012-10-01

    Directional selection is prevalent in nature, yet phenotypes tend to remain relatively constant, suggesting a limit to trait evolution. However, the genetic basis of this limit is unresolved. Given widespread pleiotropy, opposing selection on a trait may arise from the effects of the underlying alleles on other traits under selection, generating net stabilizing selection on trait genetic variance. These pleiotropic costs of trait exaggeration may arise through any number of other traits, making them hard to detect in phenotypic analyses. Stabilizing selection can be inferred, however, if genetic variance is greater among low- compared to high-fitness individuals. We extend a recently suggested approach to provide a direct test of a difference in genetic variance for a suite of cuticular hydrocarbons (CHCs) in Drosophila serrata. Despite strong directional sexual selection on these traits, genetic variance differed between high- and low-fitness individuals and was greater among the low-fitness males for seven of eight CHCs, significantly more than expected by chance. Univariate tests of a difference in genetic variance were nonsignificant but likely have low power. Our results suggest that further CHC exaggeration in D. serrata in response to sexual selection is limited by pleiotropic costs mediated through other traits. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  4. Sexual selection in Fungi

    NARCIS (Netherlands)

    Nieuwenhuis, B.P.S.

    2012-01-01

    Sexual selection is an important factor that drives evolution, in which fitness is increased, not by increasing survival or viability, but by acquiring more or better mates. Sexual selection favours traits that increase the ability of an individual to obtain more matings than other individuals

  5. Sexual selection protects against extinction

    OpenAIRE

    Lumley, Alyson; Michalczyk, Lukasz; Kitson, James; Spurgin, Lewis; Morrison, Catriona; Godwin, Joanne; Dickinson, Matthew; Martin, Oliver; Emerson, Brent; Chapman, Tracey; Gage, Matthew

    2015-01-01

    Reproduction through sex carries substantial costs, mainly because only half of sexual adults produce offspring. It has been theorised that these costs could be countered if sex allows sexual selection to clear the universal fitness constraint of mutation load. Under sexual selection, competition between (usually) males, and mate choice by (usually) females create important intraspecific filters for reproductive success, so that only a subset of males gains paternity. If reproductive success ...

  6. Sexual selection protects against extinction.

    Science.gov (United States)

    Lumley, Alyson J; Michalczyk, Łukasz; Kitson, James J N; Spurgin, Lewis G; Morrison, Catriona A; Godwin, Joanne L; Dickinson, Matthew E; Martin, Oliver Y; Emerson, Brent C; Chapman, Tracey; Gage, Matthew J G

    2015-06-25

    Reproduction through sex carries substantial costs, mainly because only half of sexual adults produce offspring. It has been theorized that these costs could be countered if sex allows sexual selection to clear the universal fitness constraint of mutation load. Under sexual selection, competition between (usually) males and mate choice by (usually) females create important intraspecific filters for reproductive success, so that only a subset of males gains paternity. If reproductive success under sexual selection is dependent on individual condition, which is contingent to mutation load, then sexually selected filtering through 'genic capture' could offset the costs of sex because it provides genetic benefits to populations. Here we test this theory experimentally by comparing whether populations with histories of strong versus weak sexual selection purge mutation load and resist extinction differently. After evolving replicate populations of the flour beetle Tribolium castaneum for 6 to 7 years under conditions that differed solely in the strengths of sexual selection, we revealed mutation load using inbreeding. Lineages from populations that had previously experienced strong sexual selection were resilient to extinction and maintained fitness under inbreeding, with some families continuing to survive after 20 generations of sib × sib mating. By contrast, lineages derived from populations that experienced weak or non-existent sexual selection showed rapid fitness declines under inbreeding, and all were extinct after generation 10. Multiple mutations across the genome with individually small effects can be difficult to clear, yet sum to a significant fitness load; our findings reveal that sexual selection reduces this load, improving population viability in the face of genetic stress.

  7. Sexual selection: Another Darwinian process.

    Science.gov (United States)

    Gayon, Jean

    2010-02-01

    Why was sexual selection so important to Darwin? And why was it de-emphasized by almost all of Darwin's followers until the second half of the 20th century? These two questions shed light on the complexity of the scientific tradition named "Darwinism". Darwin's interest in sexual selection was almost as old as his discovery of the principle of natural selection. From the beginning, sexual selection was just another "natural means of selection", although different from standard "natural selection" in its mechanism. But it took Darwin 30 years to fully develop his theory, from the early notebooks to the 1871 book The Descent of Man, and Selection in Relation to Sex. Although there is a remarkable continuity in his basic ideas about sexual selection, he emphasized increasingly the idea that sexual selection could oppose the action of natural selection and be non adaptive. In time, he also gave more weight to mate choice (especially female choice), giving explicit arguments in favor of psychological notions such as "choice" and "aesthetic sense". But he also argued that there was no strict demarcation line between natural and sexual selection, a major difficulty of the theory from the beginning. Female choice was the main reason why Alfred Russel Wallace, the co-discoverer of the principle of natural selection, engaged in a major controversy with Darwin about sexual selection. Wallace was suspicious about sexual selection in general, trying to minimize it by all sorts of arguments. And he denied entirely the existence of female choice, because he thought that it was both unnecessary and an anthropomorphic notion. This had something to do with his spiritualist convictions, but also with his conception of natural selection as a sufficient principle for the evolutionary explanation of all biological phenomena (except for the origin of mind). This is why Wallace proposed to redefine Darwinism in a way that excluded Darwin's principle of sexual selection. The main result of

  8. Sexual selection in marine plankton

    DEFF Research Database (Denmark)

    Sichlau, Mie Hylstofte

    Copepods are among the most abundant metazoans on the planet and play an important role in the marine food web. Many aspects of their ecology have consequently been studied, including details of their reproductive biology and mating behaviour. Sexual selection, the part of evolution which selects...

  9. The relationship between sexual selection and sexual conflict.

    Science.gov (United States)

    Kokko, Hanna; Jennions, Michael D

    2014-07-18

    Evolutionary conflicts of interest arise whenever genetically different individuals interact and their routes to fitness maximization differ. Sexual selection favors traits that increase an individual's competitiveness to acquire mates and fertilizations. Sexual conflict occurs if an individual of sex A's relative fitness would increase if it had a "tool" that could alter what an individual of sex B does (including the parental genes transferred), at a cost to B's fitness. This definition clarifies several issues: Conflict is very common and, although it extends outside traits under sexual selection, sexual selection is a ready source of sexual conflict. Sexual conflict and sexual selection should not be presented as alternative explanations for trait evolution. Conflict is closely linked to the concept of a lag load, which is context-dependent and sex-specific. This makes it possible to ask if one sex can "win." We expect higher population fitness if females win. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

  10. Sexual Selection and Adaptation to Novel Environments

    OpenAIRE

    Martinossi-Allibert, Ivain

    2017-01-01

    The work included in this thesis aims at exploring the environmental sensitivity of benefits and costs of sexual selection through a combined empirical and theoretical effort, to increase our understanding of the impact of environmental change on sexually reproducing populations.Can sexual selection promote adaptation to novel environments? Sexual selection for good genes should accelerate adaptation by granting higher reproductive success to individuals of high genetic quality. However, sexu...

  11. [Sexual offences--selected cases].

    Science.gov (United States)

    Łabecka, Marzena; Jarzabek-Bielecka, Grazyna; Lorkiewicz-Muszyńska, Dorota

    2013-04-01

    Expert testimony on violence victims also includes victims of sexual assault. The role of an expert is to classify the injuries by their severity as defined in art. 157 156 or 217 of the Criminal Code pertaining to crimes against health and life. Also, the role of an expert opinion is to determine whether the injuries identified during the exam occurred at the time and under the circumstances stated in medical history. The examination of sexual assault victims is conducted by two experts: a gynecologist and a forensic physician. Most examinations are performed at different times and various medical centers. The conclusions are presented in an official report. Regardless of victim age, all sexual crimes are investigated ex officio by the Police Department and the Prosecutor's Office. Further legal classification of criminal offenses is the task of an appropriate legal body and the offenses are codified in accordance with the provisions of chapter XXV of the Criminal Code, articles 197 - 205. In controversial cases, i.e. when two different expert opinions appear on the same case, or if, according to the law enforcement, a medical opinion is insufficient for some reason, an appropriate expert or team of experts is appointed to resolve the problem. To present selected cases of sexual violence victims treated at the Department of Gynecology and assessed at the Department of Forensic Medicine with reference to the challenges regarding qualification of the sustained injuries and clinical diagnoses. Research material included selected forensic opinions developed for law enforcement offices that involved victims of sexual violence. The expert opinions were prepared either on the basis of submitted evidence, or both, submitted evidence and examination of the victim at the Department of Forensic Medicine. Moreover the article presents a case of a patient examined and treated at the Department of Gynecology in Poznan. Based on the selected cases, the authors conclude that a

  12. Sexual selection and hermaphroditic organisms: Testing theory

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    Janet L. LEONARD

    2013-08-01

    Full Text Available Sexual selection is widespread if not ubiquitous in hermaphroditic organisms. Although many phenomena that have been described as sexual selection in gonochores, (e.g. harem polygamy, multiple mating, elaborate courtship, even secondary sexual characters can be found in some hermaphrodites, what is more interesting is the ways in which sexual selection in hermaphrodites may differ from dioecious taxa. In hermaphrodites, an individual’s mating success includes its success from both sexual roles. Secondly, in many simultaneously hermaphroditic taxa there is strong evidence of sexual selection and yet the ope­rational sex ratio is 1:1, by definition. Many simultaneous hermaphrodites have elaborate courtship and genital anatomy, suggesting sexual selection plays an important role in reproductive success. Sperm competition and cryptic female choice mean that the number of mates acquired is not necessarily a predictor of reproductive success. Even in simultaneous hermaphrodites with reciprocal mating, variance in reproductive success through the male role and through the female role may differ in a population. Moreover hermaphrodites may choose to emphasize one sexual role over the other. Data suggest that the preferred role varies in hermaphrodites, which creates an opportunity to test fundamental predictions and assumptions of sexual selection theory. Hermaphrodites may vary their emphasis on one sexual role over the other either developmentally or behaviorally in response to environmental or social parameters. How they use this capability in acquiring more or higher quality mates still requires study [Current Zoology 59 (4: 579–588, 2013].

  13. The effect of sexual selection on adaptation and extinction under increasing temperatures.

    Science.gov (United States)

    Parrett, Jonathan M; Knell, Robert J

    2018-04-25

    Strong sexual selection has been reported to both enhance and hinder the adaptive capacity and persistence of populations when exposed to novel environments. Consequently, how sexual selection influences population adaption and persistence under stress remains widely debated. Here, we present two empirical investigations of the fitness consequences of sexual selection on populations of the Indian meal moth, Plodia interpunctella, exposed to stable or gradually increasing temperatures. When faced with increasing temperatures, strong sexual selection was associated with both increased fecundity and offspring survival compared with populations experiencing weak sexual selection, suggesting sexual selection acts to drive adaptive evolution by favouring beneficial alleles. Strong sexual selection did not, however, delay extinction when the temperature became excessively high. By manipulating individuals' mating opportunities during fitness assays, we were able to assess the effect of multiple mating independently from the effect of population-level sexual selection, and found that polyandry has a positive effect on both fecundity and offspring survival under increasing temperatures in those populations evolving with weak sexual selection. Within stable temperatures, there were some benefits from strong sexual selection but these were not consistent across the entire experiment, possibly reflecting changing costs and benefits of sexual selection under stabilizing and directional selection. These results indicate that sexual selection can provide a buffer against climate change and increase adaptation rates within a continuously changing environment. These positive effects of sexual selection may, however, be too small to protect populations and delay extinction when environmental changes are relatively rapid. © 2018 The Author(s).

  14. Sexual Selection of Protamine 1 in Mammals.

    Science.gov (United States)

    Lüke, Lena; Tourmente, Maximiliano; Roldan, Eduardo R S

    2016-01-01

    Protamines have a crucial role in male fertility. They are involved in sperm chromatin packaging and influence the shape of the sperm head and, hence, are important for sperm performance. Protamine structure is basic with numerous arginine-rich DNA-binding domains. Postcopulatory sexual selection is thought to play an important role in protamine sequence evolution and expression. Here, we analyze patterns of evolution and sexual selection (in the form of sperm competition) acting on protamine 1 gene sequence in 237 mammalian species. We assessed common patterns as well as differences between the major mammalian subclasses (Eutheria, Metatheria) and clades. We found that a high arginine content in protamine 1 associates with a lower sperm head width, which may have an impact on sperm swimming velocity. Increase in arginine content in protamine 1 across mammals appears to take place in a way consistent with sexual selection. In metatherians, increase in sequence length correlates with sexual selection. Differences in selective pressures on sequences and codon sites were observed between mammalian clades. Our study revealed a complex evolutionary pattern of protamine 1, with different selective constraints, and effects of sexual selection, between mammalian groups. In contrast, the effect of arginine content on head shape, and the possible involvement of sperm competition, was identified across all mammals. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  15. Parental selection of children's sexual orientation.

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    Greenberg, A S; Bailey, J M

    2001-08-01

    As we learn more about the causes of sexual orientation, the likelihood increases that parents will one day be able to select the orientation of their children. This possibility (at least that of selecting for heterosexuality) has generated a great deal of concern among supporters of homosexual rights, with such selection being widely condemned as harmful and morally repugnant. Notwithstanding this widespread condemnation, and even assuming, as we do, that homosexuality is entirely acceptable morally, allowing parents, by means morally unproblematic in themselves, to select for heterosexuality would be morally acceptable. This is because allowing parents to select their children's sexual orientation would further parent's freedom to raise the sort of children they wish to raise and because selection for heterosexuality may benefit parents and children and is unlikely to cause significant harm.

  16. Evolution of molecular phenotypes under stabilizing selection

    International Nuclear Information System (INIS)

    Nourmohammad, Armita; Schiffels, Stephan; Lässig, Michael

    2013-01-01

    Molecular phenotypes are important links between genomic information and organismic functions, fitness, and evolution. Complex phenotypes, which are also called quantitative traits, often depend on multiple genomic loci. Their evolution builds on genome evolution in a complicated way, which involves selection, genetic drift, mutations and recombination. Here we develop a coarse-grained evolutionary statistics for phenotypes, which decouples from details of the underlying genotypes. We derive approximate evolution equations for the distribution of phenotype values within and across populations. This dynamics covers evolutionary processes at high and low recombination rates, that is, it applies to sexual and asexual populations. In a fitness landscape with a single optimal phenotype value, the phenotypic diversity within populations and the divergence between populations reach evolutionary equilibria, which describe stabilizing selection. We compute the equilibrium distributions of both quantities analytically and we show that the ratio of mean divergence and diversity depends on the strength of selection in a universal way: it is largely independent of the phenotype’s genomic encoding and of the recombination rate. This establishes a new method for the inference of selection on molecular phenotypes beyond the genome level. We discuss the implications of our findings for the predictability of evolutionary processes. (paper)

  17. Sexual selection studies: A NESCent catalyst meeting

    NARCIS (Netherlands)

    Roughgarden, J.; Adkins-Regan, E.; Akcay, E.; Hinde, C.A.; Hoquet, T.; O'Connor, C.; Prokop, Z.M.; Prum, R.O.; Shafir, S.; Snow, S.S.; Taylor, D.; Cleve, Van J.; Weisberg, M.

    2015-01-01

    A catalyst meeting on sexual selection studies was held in July 2013 at the facilities of the National Evolutionary Synthesis Center (NESCent) in Durham, NC. This article by a subcommittee of the participants foregrounds some of the topics discussed at the meeting. Topics mentioned here include the

  18. Natural and sexual selection against hybrid flycatchers

    NARCIS (Netherlands)

    Svedin, Nina; Wiley, Chris; Veen, Thor; Gustafsson, Lars; Qvarnstrom, Anna

    2008-01-01

    While sexual selection is generally assumed to quickly cause or strengthen prezygotic barriers between sister species, its role in causing postzygotic isolation, through the unattractiveness of intermediate hybrids, is less often examined. Combining 24 years of pedigree data and recently developed

  19. Sexual stability in the nearly dioecious Pinus johannis (Pinaceae).

    Science.gov (United States)

    Flores-Rentería, Lluvia; Molina-Freaner, Francisco; Whipple, Amy V; Gehring, Catherine A; Domínguez, C A

    2013-03-01

    Even though dioecy is a dominant sexual system among gymnosperms, little is known about its evolutionary history. Pinus johannis may represent a model system because unisexual and monoecious individuals compose its populations. The presence of unisexual individuals in other Pinus species is a consequence of sexual lability. Here we determined whether P. johannis represents the first example of a dioecious or nearly dioecious reproductive system in conifers by evaluating its sexual stability. • To assess the stability of sexual expression, we quantified the proportion of male vs. female reproductive structures produced by trees over multiple years and tested for the presence of sexual dimorphism. Sexual lability hypotheses were also examined by looking at the relationship between environmental factors and sexual expression and by comparing the reproductive behavior of P. johannis with its closest labile relative, P. edulis. • Pinus johannis is nearly dioecious: ~99% of individuals are unisexual or express a low proportion of the opposite gender with few changes in sexual expression through time. We found sexual dimorphism consistent with sexual stability. Sexual expression did not vary with tree size/age, abiotic environment, or herbivore removal, providing evidence against sexual lability. Individuals of P. johannis tended to produce only male or female strobili, whereas those of P. edulis were mainly monoecious with a gradient in the female to male strobili ratio. • This study represents the first report of a nearly stable dioecious Pinus species. The variety of sexual morphs coexisting in the same population makes P. johannis a model for studying the evolution of dioecy in gymnosperms.

  20. Sexual selection targets cetacean pelvic bones

    Science.gov (United States)

    Dines, J. P.; Otárola-Castillo, E.; Ralph, P.; Alas, J.; Daley, T.; Smith, A. D.; Dean, M. D.

    2014-01-01

    Male genitalia evolve rapidly, probably as a result of sexual selection. Whether this pattern extends to the internal infrastructure that influences genital movements remains unknown. Cetaceans (whales and dolphins) offer a unique opportunity to test this hypothesis: since evolving from land-dwelling ancestors, they lost external hind limbs and evolved a highly reduced pelvis which seems to serve no other function except to anchor muscles that maneuver the penis. Here we create a novel morphometric pipeline to analyze the size and shape evolution of pelvic bones from 130 individuals (29 species) in the context of inferred mating system. We present two main findings: 1) males from species with relatively intense sexual selection (inferred by relative testes size) have evolved relatively large penises and pelvic bones compared to their body size, and 2) pelvic bone shape diverges more quickly in species pairs that have diverged in inferred mating system. Neither pattern was observed in the anterior-most pair of vertebral ribs, which served as a negative control. This study provides evidence that sexual selection can affect internal anatomy that controls male genitalia. These important functions may explain why cetacean pelvic bones have not been lost through evolutionary time. PMID:25186496

  1. Experimental removal and elevation of sexual selection: does sexual selection generate manipulative males and resistant females?

    Science.gov (United States)

    Crudgington, Helen S; Beckerman, Andrew P; Brüstle, Lena; Green, Kathleen; Snook, Rhonda R

    2005-05-01

    Sexual conflict over reproduction can occur between males and females. In several naturally promiscuous insect species, experimental evolution studies that have enforced monogamy found evidence for sexual conflict. Here, we subjected the naturally promiscuous, sperm-heteromorphic fruit fly Drosophila pseudoobscura to enforced monogamy, standard levels of promiscuity, and elevated opportunities for promiscuity in four replicate lines. We examined the effect of male and female selection history and the proximate effect of variation in male density on female fitness parameters. We found that male density rather than male selection history explained a greater degree of female fecundity, egg hatching success, and productivity. Additionally, females selected under elevated promiscuity had greater fecundity and hatching success than did enforced monogamy females. Selection line males do not differ in their capacity to coerce females to remate, suggesting no divergence in precopulatory manipulative ability. However, these males did vary in their ability to suppress female remating, suggesting postcopulatory manipulation. These results indicate that sexual conflict can be manifested through both the proximate effects of male density and the historical levels of sexual selection and that the sexes respond differentially to these factors and further stress the multifarious channels of sexual communication that contribute to fitness.

  2. Sexually selected females in the monogamous Western Australian seahorse.

    Science.gov (United States)

    Kvarnemo, Charlotta; Moore, Glenn I; Jones, Adam G

    2007-02-22

    Studies of sexual selection in monogamous species have hitherto focused on sexual selection among males. Here, we provide empirical documentation that sexual selection can also act strongly on females in a natural population with a monogamous mating system. In our field-based genetic study of the monogamous Western Australian seahorse, Hippocampus subelongatus, sexual selection differentials and gradients show that females are under stronger sexual selection than males: mated females are larger than unmated ones, whereas mated and unmated males do not differ in size. In addition, the opportunity for sexual selection (variance in mating success divided by its mean squared) for females is almost three times that for males. These results, which seem to be generated by a combination of a male preference for larger females and a female-biased adult sex ratio, indicate that substantial sexual selection on females is a potentially important but under-appreciated evolutionary phenomenon in monogamous species.

  3. Signal trait sexual dimorphism and mutual sexual selection in Drosophila serrata.

    Science.gov (United States)

    Chenoweth, Stephen F; Blows, Mark W

    2003-10-01

    The evolution of sexual dimorphism may occur when natural and sexual selection result in different optimum trait values for males and females. Perhaps the most prominent examples of sexual dimorphism occur in sexually selected traits, for which males usually display exaggerated trait levels, while females may show reduced expression of the trait. In some species, females also exhibit secondary sexual traits that may either be a consequence of a correlated response to sexual selection on males or direct sexual selection for female secondary sexual traits. In this experiment, we simultaneously measure the intersex genetic correlations and the relative strength of sexual selection on males and females for a set of cuticular hydrocarbons in Drosophila serrata. There was significant directional sexual selection on both male and female cuticular hydrocarbons: the strength of sexual selection did not differ among the sexes but males and females preferred different cuticular hydrocarbons. In contrast with many previous studies of sexual dimorphism, intersex genetic correlations were low. The evolution of sexual dimorphism in D. serrata appears to have been achieved by sex-limited expression of traits controlled by genes on the X chromosome and is likely to be in its final stages.

  4. Sexual and Natural Selection Both Influence Male Genital Evolution

    OpenAIRE

    House, Clarissa M.; Lewis, Zenobia; Hodgson, Dave J.; Wedell, Nina; Sharma, Manmohan D.; Hunt, John; Hosken, David J.

    2013-01-01

    Rapid and divergent evolution of male genital morphology is a conspicuous and general pattern across internally fertilizing animals. Rapid genital evolution is thought to be the result of sexual selection, and the role of natural selection in genital evolution remains controversial. However, natural and sexual selection are believed to act antagonistically on male genital form. We conducted an experimental evolution study to investigate the combined effects of natural and sexual selection on ...

  5. The sexual cascade and the rise of pre-ejaculatory (Darwinian) sexual selection, sex roles, and sexual conflict.

    Science.gov (United States)

    Parker, Geoff A

    2014-08-21

    After brief historic overviews of sexual selection and sexual conflict, I argue that pre-ejaculatory sexual selection (the form of sexual selection discussed by Darwin) arose at a late stage in an inevitable succession of transitions flowing from the early evolution of syngamy to the evolution of copulation and sex roles. If certain conditions were met, this "sexual cascade" progressed inevitably, if not, sexual strategy remained fixed at a given stage. Prolonged evolutionary history of intense sperm competition/selection under external fertilization preceded the rise of advanced mobility, which generated pre-ejaculatory sexual selection, followed on land by internal fertilization and reduced sperm competition in the form of postcopulatory sexual selection. I develop a prospective model of the early evolution of mobility, which, as Darwin realized, was the catalyst for pre-ejaculatory sexual selection. Stages in the cascade should be regarded as consequential rather than separate phenomena and, as such, invalidate much current opposition to Darwin-Bateman sex roles. Potential for sexual conflict occurs throughout, greatly increasing later in the cascade, reaching its peak under precopulatory sexual selection when sex roles become highly differentiated. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

  6. Why are sexually selected weapons almost absent in females?

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    Anders BERGLUND

    2013-08-01

    Full Text Available In sex role reversed species, predominantly females evolve sexually selected traits, such as ornaments and/or weapons. Female ornaments are common and their function well documented in many species, whether sex role reversed or not. However, sexually selected female weapons seem totally absent except for small wing spurs in three jacana species, present in both males and females. This poor female weaponry is in sharp contrast to the situation in species with conventional sex roles: males commonly have evolved sexually selected weapons as well as ornaments. At the same time, females in many taxa have naturally selected weapons, used in competition over resources or in predator defence. Why are sexually selected weapons then so rare, almost absent, in females? Here I briefly review weaponry in females and the function of these weapons, conclude that the near absence of sexually selected weapons begs an explanation, and suggest that costs of sexually selected weapons may exceed costs of ornaments. Females are more constrained when evolving sexually selected traits compared to males, at least compared to those males that do not provide direct benefits, as trait costs reduce a female’s fecundity. I suggest that this constraining trade-off between trait and fecundity restricts females to evolve ornaments but rarely weapons. The same may apply to paternally investing males. Whether sexually selected weapons actually are more costly than sexually selected ornaments remains to be investigated [Current Zoology 59 (4: 564–568, 2013].

  7. Sexually antagonistic selection in human male homosexuality.

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    Andrea Camperio Ciani

    Full Text Available Several lines of evidence indicate the existence of genetic factors influencing male homosexuality and bisexuality. In spite of its relatively low frequency, the stable permanence in all human populations of this apparently detrimental trait constitutes a puzzling 'Darwinian paradox'. Furthermore, several studies have pointed out relevant asymmetries in the distribution of both male homosexuality and of female fecundity in the parental lines of homosexual vs. heterosexual males. A number of hypotheses have attempted to give an evolutionary explanation for the long-standing persistence of this trait, and for its asymmetric distribution in family lines; however a satisfactory understanding of the population genetics of male homosexuality is lacking at present. We perform a systematic mathematical analysis of the propagation and equilibrium of the putative genetic factors for male homosexuality in the population, based on the selection equation for one or two diallelic loci and Bayesian statistics for pedigree investigation. We show that only the two-locus genetic model with at least one locus on the X chromosome, and in which gene expression is sexually antagonistic (increasing female fitness but decreasing male fitness, accounts for all known empirical data. Our results help clarify the basic evolutionary dynamics of male homosexuality, establishing this as a clearly ascertained sexually antagonistic human trait.

  8. Sexual dimorphism and directional sexual selection on aposematic signals in a poison frog

    NARCIS (Netherlands)

    Maan, Martine E.; Cummings, Molly E.

    2009-01-01

    It is commonly assumed that natural selection imposed by predators is the prevailing force driving the evolution of aposematic traits. Here, we demonstrate that aposematic signals are shaped by sexual selection as well. We evaluated sexual selection for coloration brightness in populations of the

  9. Female Remating, Sperm Competition and Sexual Selection in Drosophila

    OpenAIRE

    Singh, Dr. Shree Ram; Singh, Dr. B N; Hoenigsberg, Dr. H F

    2002-01-01

    Female remating is the fundamental to evolutionary biology as it determines the pattern of sexual selection and sexual conflict. Remating in females is an important component of Drosophila mating systems because it is associated with pattern of sperm usage and sexual selection. Remating is common in females of many species of Drosophila in both natural and laboratory populations. It is reported in many insect species and vertebrates also. Female remating is prerequisite for the ...

  10. Sexual selection, germline mutation rate and sperm competition

    Directory of Open Access Journals (Sweden)

    Møller AP

    2003-04-01

    Full Text Available Abstract Background An important component of sexual selection arises because females obtain viability benefits for their offspring from their mate choice. Females choosing extra-pair fertilization generally favor males with exaggerated secondary sexual characters, and extra-pair paternity increases the variance in male reproductive success. Furthermore, females are assumed to benefit from 'good genes' from extra-pair sires. How additive genetic variance in such viability genes is maintained despite strong directional selection remains an evolutionary enigma. We propose that sexual selection is associated with elevated mutation rates, changing the balance between mutation and selection, thereby increasing variance in fitness and hence the benefits to be obtained from good genes sexual selection. Two hypotheses may account for such elevated mutation: (1 Increased sperm production associated with sperm competition may increase mutation rate. (2 Mutator alleles increase mutation rates that are revealed by the expression of condition-dependent secondary sexual characters used by choosy females during their mate choice. M Petrie has independently developed the idea that mutator alleles may account for the maintenance of genetic variation in viability despite strong directional selection. Results A comparative study of birds revealed a positive correlation between mutation rate at minisatellite loci and extra-pair paternity, but not between mutation rate and relative testes mass which is a measure of relative sperm production. Minisatellite mutation rates were not related to longevity, suggesting a meiotic rather than a mitotic origin of mutations. Conclusion We found evidence of increased mutation rate in species with more intense sexual selection. Increased mutation was not associated with increased sperm production, and we suggest that species with intense sexual selection may maintain elevated mutation rates because sexual selection continuously

  11. Understanding the link between sexual selection, sexual conflict and aging using crickets as a model.

    Science.gov (United States)

    Archer, C Ruth; Hunt, John

    2015-11-01

    Aging evolved because the strength of natural selection declines over the lifetime of most organisms. Weak natural selection late in life allows the accumulation of deleterious mutations and may favor alleles that have positive effects on fitness early in life, but costly pleiotropic effects expressed later on. While this decline in natural selection is central to longstanding evolutionary explanations for aging, a role for sexual selection and sexual conflict in the evolution of lifespan and aging has only been identified recently. Testing how sexual selection and sexual conflict affect lifespan and aging is challenging as it requires quantifying male age-dependent reproductive success. This is difficult in the invertebrate model organisms traditionally used in aging research. Research using crickets (Orthoptera: Gryllidae), where reproductive investment can be easily measured in both sexes, has offered exciting and novel insights into how sexual selection and sexual conflict affect the evolution of aging, both in the laboratory and in the wild. Here we discuss how sexual selection and sexual conflict can be integrated alongside evolutionary and mechanistic theories of aging using crickets as a model. We then highlight the potential for research using crickets to further advance our understanding of lifespan and aging. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Sexual selection predicts species richness across the animal kingdom.

    Science.gov (United States)

    Janicke, Tim; Ritchie, Michael G; Morrow, Edward H; Marie-Orleach, Lucas

    2018-05-16

    Our improving knowledge of the animal tree of life consistently demonstrates that some taxa diversify more rapidly than others, but what contributes to this variation remains poorly understood. An influential hypothesis proposes that selection arising from competition for mating partners plays a key role in promoting speciation. However, empirical evidence showing a link between proxies of this sexual selection and species richness is equivocal. Here, we collected standardized metrics of sexual selection for a broad range of animal taxa, and found that taxonomic families characterized by stronger sexual selection on males show relatively higher species richness. Thus, our data support the hypothesis that sexual selection elevates species richness. This could occur either by promoting speciation and/or by protecting species against extinction. © 2018 The Author(s).

  13. Positive allometry and the prehistory of sexual selection

    OpenAIRE

    Tomkins, Joseph L.; LeBas, Natasha R.; Witton, Mark P.; Martill, David M.; Humphries, Stuart

    2010-01-01

    The function of the exaggerated structures that adorn many fossil vertebrates remains largely unresolved. One recurrent hypothesis is that these elaborated traits had a role in thermoregulation. This orthodoxy persists despite the observation that traits exaggerated to the point of impracticality in extant organisms are almost invariably sexually selected. We use allometric scaling to investigate the role of sexual selection and thermoregulation in the evolution of exaggerated traits of the c...

  14. Darwin's explanation of races by means of sexual selection.

    Science.gov (United States)

    Millstein, Roberta L

    2012-09-01

    In Darwin's Sacred Cause, Adrian Desmond and James Moore contend that "Darwin would put his utmost into sexual selection because the subject intrigued him, no doubt, but also for a deeper reason: the theory vindicated his lifelong commitment to human brotherhood" (2009: p. 360). Without questioning Desmond and Moore's evidence, I will raise some puzzles for their view. I will show that attention to the structure of Darwin's arguments in the Descent of Man shows that they are far from straightforward. As Desmond and Moore note, Darwin seems to have intended sexual selection in non-human animals to serve as evidence for sexual selection in humans. However, Darwin's account of sexual selection in humans was different from the canonical cases that Darwin described at great length. If explaining the origin of human races was the main reason for introducing sexual selection, and if sexual selection was a key piece of Darwin's anti-slavery arguments, then it is puzzling why Darwin would have spent so much time discussing cases that did not really support his argument for the origin of human races, and it is also puzzling that his argument for the origin of human races would be so (atypically) poor. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Student-Initiated Sexual Health Selective as a Curricular Tool

    Directory of Open Access Journals (Sweden)

    Katie Johnson, BS

    2015-06-01

    Conclusions: The 1-week SHS was successfully implemented through the teamwork of a medical student and faculty champion. It resulted in more accurate knowledge and more open attitudes toward sexual health among participating medical students. Potential benefits to undergraduate medical educators are reviewed. Johnson K, Rullo J, and Faubion S. Student-initiated sexual health selective as a curricular tool. Sex Med 2015;3:118–127.

  16. Sexual selection affects local extinction and turnover in bird communities

    Science.gov (United States)

    Doherty, P.F.; Sorci, G.; Royle, J. Andrew; Hines, J.E.; Nichols, J.D.; Boulinier, T.

    2003-01-01

    Predicting extinction risks has become a central goal for conservation and evolutionary biologists interested in population and community dynamics. Several factors have been put forward to explain risks of extinction, including ecological and life history characteristics of individuals. For instance, factors that affect the balance between natality and mortality can have profound effects on population persistence. Sexual selection has been identified as one such factor. Populations under strong sexual selection experience a number of costs ranging from increased predation and parasitism to enhanced sensitivity to environmental and demographic stochasticity. These findings have led to the prediction that local extinction rates should be higher for species/populations with intense sexual selection. We tested this prediction by analyzing the dynamics of natural bird communities at a continental scale over a period of 21 years (1975-1996), using relevant statistical tools. In agreement with the theoretical prediction, we found that sexual selection increased risks of local extinction (dichromatic birds had on average a 23% higher local extinction rate than monochromatic species). However, despite higher local extinction probabilities, the number of dichromatic species did not decrease over the period considered in this study. This pattern was caused by higher local turnover rates of dichromatic species, resulting in relatively stable communities for both groups of species. Our results suggest that these communities function as metacommunities, with frequent local extinctions followed by colonization. Anthropogenic factors impeding dispersal might therefore have a significant impact on the global persistence of sexually selected species.

  17. Sexual selection and magic traits in speciation with gene flow

    Directory of Open Access Journals (Sweden)

    Maria R. SERVEDIO, Michael KOPP

    2012-06-01

    Full Text Available The extent to which sexual selection is involved in speciation with gene flow remains an open question and the subject of much research. Here, we propose that some insight can be gained from considering the concept of magic traits (i.e., traits involved in both reproductive isolation and ecological divergence. Both magic traits and other, “non-magic”, traits can contribute to speciation via a number of specific mechanisms. We argue that many of these mechanisms are likely to differ widely in the extent to which they involve sexual selection. Furthermore, in some cases where sexual selection is present, it may be prone to inhibit rather than drive speciation. Finally, there are a priori reasons to believe that certain categories of traits are much more effective than others in driving speciation. The combination of these points suggests a classification of traits that may shed light on the broader role of sexual selection in speciation with gene flow. In particular, we suggest that sexual selection can act as a driver of speciation in some scenarios, but may play a negligible role in potentially common categories of magic traits, and may be likely to inhibit speciation in common categories of non-magic traits [Current Zoology 58 (3: 507–513, 2012].

  18. Positive allometry and the prehistory of sexual selection.

    Science.gov (United States)

    Tomkins, Joseph L; LeBas, Natasha R; Witton, Mark P; Martill, David M; Humphries, Stuart

    2010-08-01

    The function of the exaggerated structures that adorn many fossil vertebrates remains largely unresolved. One recurrent hypothesis is that these elaborated traits had a role in thermoregulation. This orthodoxy persists despite the observation that traits exaggerated to the point of impracticality in extant organisms are almost invariably sexually selected. We use allometric scaling to investigate the role of sexual selection and thermoregulation in the evolution of exaggerated traits of the crested pterosaur Pteranodon longiceps and the sail-backed eupelycosaurs Dimetrodon and Edaphosaurus. The extraordinarily steep positive allometry of the head crest of Pteranodon rules out all of the current hypotheses for this trait's main function other than sexual signaling. We also find interspecific patterns of allometry and sexual dimorphism in the sails of Dimetrodon and patterns of elaboration in Edaphosaurus consistent with a sexually selected function. Furthermore, small ancestral, sail-backed pelycosaurs would have been too small to need adaptations to thermoregulation. Our results question the popular view that the elaborated structures of these fossil species evolved as thermoregulatory organs and provide evidence in support of the hypothesis that Pteranodon crests and eupelycosaur sails are among the earliest and most extreme examples of elaborate sexual signals in the evolution of terrestrial vertebrates.

  19. Sexual selection halts the relaxation of protamine 2 among rodents.

    Directory of Open Access Journals (Sweden)

    Lena Lüke

    Full Text Available Sexual selection has been proposed as the driving force promoting the rapid evolutionary changes observed in some reproductive genes including protamines. We test this hypothesis in a group of rodents which show marked differences in the intensity of sexual selection. Levels of sperm competition were not associated with the evolutionary rates of protamine 1 but, contrary to expectations, were negatively related to the evolutionary rate of cleaved- and mature-protamine 2. Since both domains were found to be under relaxation, our findings reveal an unforeseen role of sexual selection: to halt the degree of degeneration that proteins within families may experience due to functional redundancy. The degree of relaxation of protamine 2 in this group of rodents is such that in some species it has become dysfunctional and it is not expressed in mature spermatozoa. In contrast, protamine 1 is functionally conserved but shows directed positive selection on specific sites which are functionally relevant such as DNA-anchoring domains and phosphorylation sites. We conclude that in rodents protamine 2 is under relaxation and that sexual selection removes deleterious mutations among species with high levels of sperm competition to maintain the protein functional and the spermatozoa competitive.

  20. Novel host plant leads to the loss of sexual dimorphism in a sexually selected male weapon.

    Science.gov (United States)

    Allen, Pablo E; Miller, Christine W

    2017-08-16

    In this time of massive global change, species are now frequently interacting with novel players. Greater insight into the impact of these novel interactions on traits linked to fitness is essential, because effects on these traits can hinder population existence or promote rapid adaptation. Sexually selected weapons and ornaments frequently influence fitness and often have heightened condition-dependence in response to nutrition. Condition-dependence in response to different ecological conditions, a form of developmental plasticity, may be responsible for much of the intraspecific variation in sexually selected ornaments and weapons in wild populations. Here we examined the consequences of developing on a novel plant for the expression of size and shape in the leaf-footed cactus bug Narnia femorata (Hemiptera: Coreidae). The males of this species possess enlarged, sexually dimorphic femurs on their hind legs. These legs are used as weapons in male-male contests. Females are typically larger in overall body size. Our study revealed that developing upon a novel host can lead to pronounced phenotypically plastic change in sexually dimorphic traits. Male hind femurs were greatly impacted by the novel diet to the extent that the sexual dimorphism in hind femurs was lost. Further, dimorphism in body size increased, as males became tiny adults while females better maintained their body size. These patterns underscore the complex effects that novel species interactions may have on sexual phenotypes. © 2017 The Author(s).

  1. Historical and Experimental Evidence of Sexual Selection for War Heroism

    NARCIS (Netherlands)

    Rusch, H.; Leunissen, J.L.M.; van Vugt, M.

    2015-01-01

    We report three studies which test a sexual selection hypothesis for male war heroism. Based on evolutionary theories of mate choice we hypothesize that men signal their fitness through displaying heroism in combat. First, we report the results of an archival study on US-American soldiers who fought

  2. Natural Aphrodisiacs-A Review of Selected Sexual Enhancers.

    Science.gov (United States)

    West, Elizabeth; Krychman, Michael

    2015-10-01

    The Food and Drug Administration defines an aphrodisiac drug product as "any product that bears labeling claims that it will arouse or increase sexual desire, or that it will improve sexual performance." Presently, there are no approved medications for the treatment of lowered desire for women, and many opt for "natural" products. The aim of this article was to review the most popular and currently used aphrodisiac products marketed in the United States. The safety and efficacy of animal- and plant-based aphrodisiacs, vitamins and minerals, and popular over-the-counter combination supplements have been reviewed. An English PubMed literature search was performed using the key words "sexuality," "sex," "aphrodisiac," and "sexual enhancer." Approximately 50 articles were reviewed by the authors. The authors used relevant case series, case-controlled, and randomized clinical trial data. Products were evaluated based on the quality of research, and their known efficacy and safety considerations. Products with low risk and potential benefit for sexual response based on prior research studies were highlighted. Research has demonstrated that the risks of yohimbine, Spanish fly, mad honey, and Bufo toad may outweigh any benefit, and these products should be avoided. Other products, such as Maca, Tribulus, Ginkgo, and ginseng, have limited but emerging data. Randomized clinical trial data are often lacking, but future research should be performed to further elucidate the efficacy and safety of these products. Future randomized clinical trials are warranted before health care practitioners can recommend most aphrodisiac products. There remain some medical concerns with drug interactions, purity, reliability, and safety. West E and Krychman M. Natural aphrodisiacs-A review of selected sexual enhancers.. Copyright © 2015 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

  3. Contributions of natural and sexual selection to the evolution of premating reproductive isolation: a research agenda.

    Science.gov (United States)

    Safran, Rebecca J; Scordato, Elizabeth S C; Symes, Laurel B; Rodríguez, Rafael L; Mendelson, Tamra C

    2013-11-01

    Speciation by divergent natural selection is well supported. However, the role of sexual selection in speciation is less well understood due to disagreement about whether sexual selection is a mechanism of evolution separate from natural selection, as well as confusion about various models and tests of sexual selection. Here, we outline how sexual selection and natural selection are different mechanisms of evolutionary change, and suggest that this distinction is critical when analyzing the role of sexual selection in speciation. Furthermore, we clarify models of sexual selection with respect to their interaction with ecology and natural selection. In doing so, we outline a research agenda for testing hypotheses about the relative significance of divergent sexual and natural selection in the evolution of reproductive isolation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Chemical communication, sexual selection, and introgression in wall lizards.

    Science.gov (United States)

    MacGregor, Hannah E A; Lewandowsky, Rachel A M; d'Ettorre, Patrizia; Leroy, Chloé; Davies, Noel W; While, Geoffrey M; Uller, Tobias

    2017-10-01

    Divergence in communication systems should influence the likelihood that individuals from different lineages interbreed, and consequently shape the direction and rate of hybridization. Here, we studied the role of chemical communication in hybridization, and its contribution to asymmetric and sexually selected introgression between two lineages of the common wall lizard (Podarcis muralis). Males of the two lineages differed in the chemical composition of their femoral secretions. Chemical profiles provided information regarding male secondary sexual characters, but the associations were variable and inconsistent between lineages. In experimental contact zones, chemical composition was weakly associated with male reproductive success, and did not predict the likelihood of hybridization. Consistent with these results, introgression of chemical profiles in a natural hybrid zone resembled that of neutral nuclear genetic markers overall, but one compound in particular (tocopherol methyl ether) matched closely the introgression of visual sexual characters. These results imply that associations among male chemical profiles, sexual characters, and reproductive success largely reflect transient and environmentally driven effects, and that genetic divergence in chemical composition is largely neutral. We therefore suggest that femoral secretions in wall lizards primarily provide information about residency and individual identity rather than function as sexual signals. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  5. Nonsteroidal selective androgen receptor modulators enhance female sexual motivation.

    Science.gov (United States)

    Jones, Amanda; Hwang, Dong Jin; Duke, Charles B; He, Yali; Siddam, Anjaiah; Miller, Duane D; Dalton, James T

    2010-08-01

    Women experience a decline in estrogen and androgen levels after natural or surgically induced menopause, effects that are associated with a loss of sexual desire and bone mineral density. Studies in our laboratories have shown the beneficial effects of selective androgen receptor modulators (SARMs) in the treatment of osteoporosis and muscle wasting in animal models. A series of S-3-(phenoxy)-2-hydroxy-2-methyl-N-(4-cyano-3-trifluoromethyl-phenyl)-propionamide analogs was synthesized to evaluate the effects of B-ring substitutions on in vitro and in vivo pharmacologic activity, especially female sexual motivation. The androgen receptor (AR) relative binding affinities ranged from 0.1 to 26.5% (relative to dihydrotestosterone) and demonstrated a range of agonist activity at 100 nM. In vivo pharmacologic activity was first assessed by using male rats. Structural modifications to the B-ring significantly affected the selectivity of the SARMs, demonstrating that single-atom substitutions can dramatically and unexpectedly influence activity in androgenic (i.e., prostate) and anabolic (i.e., muscle) tissues. (S)-N-(4-cyano-3-trifluoromethyl-phenyl)-3-(3-fluoro,4-chlorophenoxy)-2-hydroxy-2-methyl-propanamide (S-23) displayed full agonist activity in androgenic and anabolic tissues; however, the remaining SARMs were more prostate-sparing, selectively maintaining the size of the levator ani muscle in castrated rats. The partner-preference paradigm was used to evaluate the effects of SARMs on female sexual motivation. With the exception of two four-halo substituted analogs, the SARMs increased sexual motivation in ovariectomized rats, with potency and efficacy comparable with testosterone propionate. These results indicate that the AR is important in regulating female libido given the nonaromatizable nature of SARMs and it could be a superior alternative to steroidal testosterone preparations in the treatment of hypoactive sexual desire disorder.

  6. Postcopulatory sexual selection influences baculum evolution in primates and carnivores.

    Science.gov (United States)

    Brindle, Matilda; Opie, Christopher

    2016-12-14

    The extreme morphological variability of the baculum across mammals is thought to be the result of sexual selection (particularly, high levels of postcopulatory selection). However, the evolutionary trajectory of the mammalian baculum is little studied and evidence for the adaptive function of the baculum has so far been elusive. Here, we use Markov chain Monte Carlo methods implemented in a Bayesian phylogenetic framework to reconstruct baculum evolution across the mammalian class and investigate the rate of baculum length evolution within the primate order. We then test the effects of testes mass (postcopulatory sexual selection), polygamy, seasonal breeding and intromission duration on the baculum in primates and carnivores. The ancestral mammal did not have a baculum, but both ancestral primates and carnivores did. No relationship was found between testes mass and baculum length in either primates or carnivores. Intromission duration correlated with baculum presence over the course of primate evolution, and prolonged intromission predicts significantly longer bacula in extant primates and carnivores. Both polygamous and seasonal breeding systems predict significantly longer bacula in primates. These results suggest the baculum plays an important role in facilitating reproductive strategies in populations with high levels of postcopulatory sexual selection. © 2016 The Authors.

  7. Sexual selection is influenced by both developmental and adult environments.

    Science.gov (United States)

    Gillespie, Stephanie R; Scarlett Tudor, M; Moore, Allen J; Miller, Christine W

    2014-12-01

    Sexual selection is often assumed to be strong and consistent, yet increasing research shows it can fluctuate over space and time. Few experimental studies have examined changes in sexual selection in response to natural environmental variation. Here, we use a difference in resource quality to test for the influence of past environmental conditions and current environmental conditions on male and female mate choice and resulting selection gradients for leaf-footed cactus bugs, Narnia femorata. We raised juveniles on natural high- and low-quality diets, cactus pads with and without ripe cactus fruits. New adults were again assigned a cactus pad with or without fruit, paired with a potential mate, and observed for mating behaviors. We found developmental and adult encounter environments affected mating decisions and the resulting patterns of sexual selection for both males and females. Males were not choosy in the low-quality encounter environment, cactus without fruit, but they avoided mating with small females in the high-quality encounter environment. Females were choosy in both encounter environments, avoiding mating with small males. However, they were the choosiest when they were in the low-quality encounter environment. Female mate choice was also context dependent by male developmental environment. Females were more likely to mate with males that had developed on cactus with fruit when they were currently in the cactus with fruit environment. This pattern disappeared when females were in the cactus without fruit environment. Altogether, these results experimentally demonstrate context-dependent mate choice by both males and females. Furthermore, we demonstrate that simple, seasonal changes in resources can lead to fluctuations in sexual selection. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  8. A longitudinal study of the effects of premarital communication, relationship stability, and self-esteem on sexual satisfaction in the first year of marriage.

    Science.gov (United States)

    Larson, J H; Anderson, S M; Holman, T B; Niemann, B K

    1998-01-01

    This study examined select premarital factors from the ecosystemic perspective hypothesized to influence marital sexual satisfaction in the first year of marriage. A sample of 70 couples was administered by the Preparation of Marriage Questionnaire (PREP-M) a few months prior to marriage to measure premarital levels of empathy, self-disclosure, open communication, relationship stability, and self-esteem. At 1 year of marriage, their sexual satisfaction was assessed using the Index of Sexual Satisfaction (ISS). Using multiple regression analyses it was found that the best premarital predictors of husband's marital sexual satisfaction were wives' self-esteem, wives' open communication, and wives' relationship stability. The best predictors for wives' marital sexual satisfaction were wives' self-esteem, wives' open communication, and husbands' empathic communication. Conclusions and implications for premarital counselling and family life education are discussed.

  9. Sexual selection and physical attractiveness : Implications for mating dynamics.

    Science.gov (United States)

    Gangestad, S W

    1993-09-01

    Sexual selection processes have received much attention in recent years, attention reflected in interest in human mate preferences. Among these mate preferences are preferences for physical attractiveness. Preferences in and of themselves, however, do not fully explain the nature of the relationships that individuals attain. A tacit negotiation process underlies relationship formation and maintenance. The notion that preferences for physical attractiveness evolved under parasite-driven "good genes" sexual selection leads to predictions about the nature of trade-offs that individuals make between mates' physical attractiveness and investment potential. These predictions and relevant data are explored, with a primary emphasis on women's preferences for men's qualities. In addition, further implications of trade-offs are examined, most notably (a) the impact of environmental variations on the nature of mating and (b) some effects of trade-offs on infidelity and male attempts to control women.

  10. The Temporal Stability of Lack of Sexual Attraction Across Young Adulthood.

    Science.gov (United States)

    Cranney, Stephen

    2016-04-01

    There is a large and growing literature on the stability of sexual orientation across the lifespan. However, virtually no studies have been conducted on the longitudinal stability of any dimension of asexuality. Here I utilized Kinsey scale-type data from Wave III and Wave IV of the Add Health survey to measure the stability of indicating "not sexually attracted to either males or females" in a forced-choice, Kinsey-type scale and during the time participants were moving through early adulthood (18-26 years in Wave III and 24-32 years in Wave IV). I found that, for the most part, individuals who reported no sexual attraction in Wave III were not the same individuals who reported no sexual attraction in Wave IV, with only three out of the 25 in Wave III who indicated no sexual attraction going on to do the same in Wave IV. This inter-wave consistency was lower than it was for other sexual minorities. However, indicating no sexual attraction in one wave was still a statistically significant predictor of indicating no sexual attraction in the other wave, as was refusing to answer or indicating the "don't know" option in the other wave. These findings do not necessarily denote change in sexual attraction across waves; the fact that not answering the question in one wave was a significant predictor of indicating no sexual attraction in the other wave provides quantitative evidence for the ambiguities involved in sexual identities when sexuality is taken for granted in the broader culture. This ambiguity affects the operationalization and quantification of asexuality.

  11. Biometric evidence that sexual selection has shaped the hominin face.

    Directory of Open Access Journals (Sweden)

    Eleanor M Weston

    2007-08-01

    Full Text Available We consider sex differences in human facial morphology in the context of developmental change. We show that at puberty, the height of the upper face, between the lip and the brow, develops differently in males and females, and that these differences are not explicable in terms of sex differences in body size. We find the same dimorphism in the faces of human ancestors. We propose that the relative shortening in men and lengthening in women of the anterior upper face at puberty is the mechanistic consequence of extreme maxillary rotation during ontogeny. A link between this developmental model and sexual dimorphism is made for the first time, and provides a new set of morphological criteria to sex human crania. This finding has important implications for the role of sexual selection in the evolution of anthropoid faces and for theories of human facial attractiveness.

  12. Sexual differences in telomere selection in the wild.

    Science.gov (United States)

    Olsson, Mats; Pauliny, Angela; Wapstra, Erik; Uller, Tobias; Schwartz, Tonia; Miller, Emily; Blomqvist, Donald

    2011-05-01

    Telomere length is restored primarily through the action of the reverse transcriptase telomerase, which may contribute to a prolonged lifespan in some but not all species and may result in longer telomeres in one sex than the other. To what extent this is an effect of proximate mechanisms (e.g. higher stress in males, higher oestradiol/oestrogen levels in females), or is an evolved adaptation (stronger selection for telomere length in one sex), usually remains unknown. Sand lizard (Lacerta agilis) females have longer telomeres than males and better maintain telomere length through life than males do. We also show that telomere length more strongly contributes to life span and lifetime reproductive success in females than males and that telomere length is under sexually diversifying selection in the wild. Finally, we performed a selection analysis with number of recruited offspring into the adult population as a response variable with telomere length, life span and body size as predictor variables. This showed significant differences in selection pressures between the sexes with strong ongoing selection in females, with these three predictors explaining 63% of the variation in recruitment. Thus, the sexually dimorphic telomere dynamics with longer telomeres in females is a result of past and ongoing selection in sand lizards. Finally, we compared the results from our selection analyses based on Telometric-derived data to the results based on data generated by the software ImageJ. ImageJ resulted in shorter average telomere length, but this difference had virtually no qualitative effect on the patterns of ongoing selection. © 2011 Blackwell Publishing Ltd.

  13. Homage to Bateman: sex roles predict sex differences in sexual selection.

    Science.gov (United States)

    Fritzsche, Karoline; Arnqvis, Göran

    2013-07-01

    Classic sex role theory predicts that sexual selection should be stronger in males in taxa showing conventional sex roles and stronger in females in role reversed mating systems. To test this very central prediction and to assess the utility of different measures of sexual selection, we estimated sexual selection in both sexes in four seed beetle species with divergent sex roles using a novel experimental design. We found that sexual selection was sizeable in females and the strength of sexual selection was similar in females and males in role-reversed species. Sexual selection was overall significantly stronger in males than in females and residual selection formed a substantial component of net selection in both sexes. Furthermore, sexual selection in females was stronger in role-reversed species compared to species with conventional sex roles. Variance-based measures of sexual selection (the Bateman gradient and selection opportunities) were better predictors of sexual dimorphism in reproductive behavior and morphology across species compared to trait-based measures (selection differentials). Our results highlight the importance of using assays that incorporate components of fitness manifested after mating. We suggest that the Bateman gradient is generally the most informative measure of the strength of sexual selection in comparisons across sexes and/or species. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  14. Gender differences in the sexual behaviour of selected adolescents ...

    African Journals Online (AJOL)

    Using the Falaye Adolescent' Sexual Behaviour Inventory (FASBI), adolescents' sexual behaviour was assessed using the proximate determinants of attitude towards pubertal changes and reproductive biology, adolescent source of sex information, adolescent sexual activities (intercourse and contraception) and attitude ...

  15. Seasonal change in the opportunity for sexual selection

    Czech Academy of Sciences Publication Activity Database

    Reichard, Martin; Smith, C.; Bryja, Josef

    2008-01-01

    Roč. 17, č. 2 (2008), s. 642-651 ISSN 0962-1083 R&D Projects: GA AV ČR KJB600930501 Grant - others:British Ecological Society(GB) ECPG 551/617 Institutional research plan: CEZ:AV0Z60930519 Keywords : bitterling * body size * sexual selection * mating success * reproductive skew Subject RIV: EH - Ecology, Behaviour Impact factor: 5.325, year: 2008 http://www.blackwell-synergy.com/doi/pdf/10.1111/j.1365-294X.2007.03602.x

  16. The effects of the dopamine stabilizer (-)-OSU6162 on aggressive and sexual behavior in rodents.

    Science.gov (United States)

    Studer, E; Näslund, J; Westman, A; Carlsson, A; Eriksson, E

    2016-03-22

    The dopamine stabilizer (-)-OSU61612 dampens locomotion in rodents rendered hyperactive by exposure to a novel environment or treatment with amphetamine, but stimulates locomotion in habituated animals displaying low motor activity, tentatively exerting this profile by selectively blocking extrasynaptic D2 receptors. The major aim of the present study was to explore the possible usefulness of (-)-OSU61612 as an anti-aggressive drug. To this end, the effect of (-)-OSU61612 on isolation-induced aggression in male mice and estrous cycle-dependent aggression in female rats were studied using the resident intruder test; in addition, the possible influence of (-)-OSU61612 on sexual behavior in male mice and on elevated plus maze (EPM) performance in male rats were assessed. (-)-OSU61612 at doses influencing neither locomotion nor sexual activity reduced aggression in male mice. The effect was observed also in serotonin-depleted animals and is hence probably not caused by the antagonism of serotonin receptors displayed by the drug; refuting the possibility that it is due to 5-HT1B activation, it was also not counteracted by isamoltane. (-)-OSU61612 did not display the profile of an anxiogenic or anxiolytic drug in the EPM but caused a general reduction in activity that is well in line with the previous finding that it reduces exploratory behavior of non-habituated animals. In line with the observations in males, (-)-OSU61612 reduced estrus cycle-related aggression in female Wistar rats, a tentative animal model of premenstrual dysphoria. By stabilizing dopaminergic transmission, (-)-OSU61612 may prove useful as a well-tolerated treatment of various forms of aggression and irritability.

  17. The Stability of Intimate Partner Violence Perpetration From Adolescence to Emerging Adulthood in Sexual Minorities.

    Science.gov (United States)

    Shorey, Ryan C; Fite, Paula J; Cohen, Joseph R; Stuart, Gregory L; Temple, Jeff R

    2018-06-01

    The objective of this study was to examine the stability of physical and sexual intimate partner violence (IPV) perpetration from adolescence to emerging adulthood among sexual minorities. Adolescents who identified as a sexual minority (N = 135; 71.1% female; mean age = 15.02, standard deviation=.77; 34.1% African-American/black, 26.7% white, 22.2% Hispanic) from southeast Texas were assessed annually for 6 years on their IPV perpetration. Structural equation modeling demonstrated that physical IPV perpetration was modestly stable across years 1-4 (24.6%, 24.6%, 26.4%, and 21.6%, respectively), decreased in year 5 (18.6%), and increased in year 6 (24.5%). The stability of sexual IPV perpetration was high across all 6 years (14.3%, 13%, 14.9%, 10.8%, 12.4%, and 14.4%). This is the first study to examine the stability of IPV perpetration among sexual minority adolescents. Findings suggest that the development of interventions for IPV among sexual minority adolescents is needed, as IPV is unlikely to desist from adolescence to emerging adulthood. Copyright © 2017 The Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  18. Males that drop a sexually selected weapon grow larger testes.

    Science.gov (United States)

    Joseph, Paul N; Emberts, Zachary; Sasson, Daniel A; Miller, Christine W

    2018-01-01

    Costly sexually selected weapons are predicted to trade off with postcopulatory traits, such as testes. Although weapons can be important for achieving access to females, individuals of some species can permanently drop (i.e. autotomize) their weapons, without regeneration, to escape danger. We capitalized on this natural behavior to experimentally address whether the loss of a sexually selected weapon leads to increased testes investment in the leaf-footed cactus bug, Narnia femorata Stål (Hemiptera: Coreidae). In a second experiment, we measured offspring production for males that lost a weapon during development. As predicted, males that dropped a hind limb during development grew significantly larger testes than the control treatments. Hind-limb autotomy did not result in the enlargement of other nearby traits. Our results are the first to experimentally demonstrate that males compensate for natural weapon loss by investing more in testes. In a second experiment we found that females paired with males that lost a hind limb had 40% lower egg hatching success than females paired with intact males, perhaps because of lower mating receptivity to males with a lost limb. Importantly, in those cases where viable offspring were produced, males missing a hind limb produced 42% more offspring than males with intact limbs. These results suggest that the loss of a hind-limb weapon can, in some cases, lead to greater fertilization success. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  19. Sexual selection and the evolution of brain size in primates.

    Science.gov (United States)

    Schillaci, Michael A

    2006-12-20

    Reproductive competition among males has long been considered a powerful force in the evolution of primates. The evolution of brain size and complexity in the Order Primates has been widely regarded as the hallmark of primate evolutionary history. Despite their importance to our understanding of primate evolution, the relationship between sexual selection and the evolutionary development of brain size is not well studied. The present research examines the evolutionary relationship between brain size and two components of primate sexual selection, sperm competition and male competition for mates. Results indicate that there is not a significant relationship between relative brain size and sperm competition as measured by relative testis size in primates, suggesting sperm competition has not played an important role in the evolution of brain size in the primate order. There is, however, a significant negative evolutionary relationship between relative brain size and the level of male competition for mates. The present study shows that the largest relative brain sizes among primate species are associated with monogamous mating systems, suggesting primate monogamy may require greater social acuity and abilities of deception.

  20. Sexual selection and the evolution of brain size in primates.

    Directory of Open Access Journals (Sweden)

    Michael A Schillaci

    Full Text Available Reproductive competition among males has long been considered a powerful force in the evolution of primates. The evolution of brain size and complexity in the Order Primates has been widely regarded as the hallmark of primate evolutionary history. Despite their importance to our understanding of primate evolution, the relationship between sexual selection and the evolutionary development of brain size is not well studied. The present research examines the evolutionary relationship between brain size and two components of primate sexual selection, sperm competition and male competition for mates. Results indicate that there is not a significant relationship between relative brain size and sperm competition as measured by relative testis size in primates, suggesting sperm competition has not played an important role in the evolution of brain size in the primate order. There is, however, a significant negative evolutionary relationship between relative brain size and the level of male competition for mates. The present study shows that the largest relative brain sizes among primate species are associated with monogamous mating systems, suggesting primate monogamy may require greater social acuity and abilities of deception.

  1. Sexual selection and allometry: a critical reappraisal of the evidence and ideas.

    Science.gov (United States)

    Bonduriansky, Russell

    2007-04-01

    One of the most pervasive ideas in the sexual selection literature is the belief that sexually selected traits almost universally exhibit positive static allometries (i.e., within a sample of conspecific adults, larger individuals have disproportionally larger traits). In this review, I show that this idea is contradicted by empirical evidence and theory. Although positive allometry is a typical attribute of some sexual traits in certain groups, the preponderance of positively allometric sexual traits in the empirical literature apparently results from a sampling bias reflecting a fascination with unusually exaggerated (bizarre) traits. I review empirical examples from a broad range of taxa illustrating the diversity of allometric patterns exhibited by signal, weapon, clasping and genital traits, as well as nonsexual traits. This evidence suggests that positive allometry may be the exception rather than the rule in sexual traits, that directional sexual selection does not necessarily lead to the evolution of positive allometry and, conversely, that positive allometry is not necessarily a consequence of sexual selection, and that many sexual traits exhibit sex differences in allometric intercept rather than slope. Such diversity in the allometries of secondary sexual traits is to be expected, given that optimal allometry should reflect resource allocation trade-offs, and patterns of sexual and viability selection on both trait size and body size. An unbiased empirical assessment of the relation between sexual selection and allometry is an essential step towards an understanding of this diversity.

  2. Positively selected sites in cetacean myoglobins contribute to protein stability

    DEFF Research Database (Denmark)

    Dasmeh, Pouria; Serohijos, Adrian W R; Kepp, Kasper P

    2013-01-01

    Since divergence ∼50 Ma ago from their terrestrial ancestors, cetaceans underwent a series of adaptations such as a ∼10-20 fold increase in myoglobin (Mb) concentration in skeletal muscle, critical for increasing oxygen storage capacity and prolonging dive time. Whereas the O2-binding affinity...... between Mb folding stability and protein abundance, suggesting that a selection pressure for stability acts proportionally to higher expression. We also identify a major divergence event leading to the common ancestor of whales, during which major stabilization occurred. Most of the positively selected...

  3. Ensembling Variable Selectors by Stability Selection for the Cox Model

    Directory of Open Access Journals (Sweden)

    Qing-Yan Yin

    2017-01-01

    Full Text Available As a pivotal tool to build interpretive models, variable selection plays an increasingly important role in high-dimensional data analysis. In recent years, variable selection ensembles (VSEs have gained much interest due to their many advantages. Stability selection (Meinshausen and Bühlmann, 2010, a VSE technique based on subsampling in combination with a base algorithm like lasso, is an effective method to control false discovery rate (FDR and to improve selection accuracy in linear regression models. By adopting lasso as a base learner, we attempt to extend stability selection to handle variable selection problems in a Cox model. According to our experience, it is crucial to set the regularization region Λ in lasso and the parameter λmin properly so that stability selection can work well. To the best of our knowledge, however, there is no literature addressing this problem in an explicit way. Therefore, we first provide a detailed procedure to specify Λ and λmin. Then, some simulated and real-world data with various censoring rates are used to examine how well stability selection performs. It is also compared with several other variable selection approaches. Experimental results demonstrate that it achieves better or competitive performance in comparison with several other popular techniques.

  4. Sexual Selection and the Evolution of Human Sex Differences

    Directory of Open Access Journals (Sweden)

    David C. Geary

    2006-12-01

    Full Text Available Darwin’s (1871 theory of sexual selection and the associated mechanisms of intrasexual competition (e.g., male-male competition and intersexual choice (e.g., female choice of mates have guided the scientific study of sex differences in hundreds of non-human species. These mechanisms and several recent advances in our understanding of the evolution and expression of sex differences in non-human species are described. The usefulness of this theory for approaching the study human sex differences is illustrated with discussion of patterns of women’s mate preferences and choices and with discussion of men’s one-on-one and coalitional competition. A comparison of these aspects of intersexual choice and intrasexual competition in humans and non-human species is provided, as is discussion of cultural variation in the expression of these behaviors. cultural influences (Maccoby & Jacklin, 1974.

  5. Quantitative genetic models of sexual selection by male choice.

    Science.gov (United States)

    Nakahashi, Wataru

    2008-09-01

    There are many examples of male mate choice for female traits that tend to be associated with high fertility. I develop quantitative genetic models of a female trait and a male preference to show when such a male preference can evolve. I find that a disagreement between the fertility maximum and the viability maximum of the female trait is necessary for directional male preference (preference for extreme female trait values) to evolve. Moreover, when there is a shortage of available male partners or variance in male nongenetic quality, strong male preference can evolve. Furthermore, I also show that males evolve to exhibit a stronger preference for females that are more feminine (less resemblance to males) than the average female when there is a sexual dimorphism caused by fertility selection which acts only on females.

  6. Structural adaptations to diverse fighting styles in sexually selected weapons.

    Science.gov (United States)

    McCullough, Erin L; Tobalske, Bret W; Emlen, Douglas J

    2014-10-07

    The shapes of sexually selected weapons differ widely among species, but the drivers of this diversity remain poorly understood. Existing explanations suggest weapon shapes reflect structural adaptations to different fighting styles, yet explicit tests of this hypothesis are lacking. We constructed finite element models of the horns of different rhinoceros beetle species to test whether functional specializations for increased performance under species-specific fighting styles could have contributed to the diversification of weapon form. We find that horns are both stronger and stiffer in response to species-typical fighting loads and that they perform more poorly under atypical fighting loads, which suggests weapons are structurally adapted to meet the functional demands of fighting. Our research establishes a critical link between weapon form and function, revealing one way male-male competition can drive the diversification of animal weapons.

  7. Stability of Sexual Attractions Across Different Timescales: The Roles of Bisexuality and Gender.

    Science.gov (United States)

    Diamond, Lisa M; Dickenson, Janna A; Blair, Karen L

    2017-01-01

    We examined the stability of same-sex and other-sex attractions among 294 heterosexual, lesbian, gay, and bisexual men and women between the ages of 18 and 40 years. Participants used online daily diaries to report the intensity of each day's strongest same-sex and other-sex attraction, and they also reported on changes they recalled experiencing in their attractions since adolescence. We used multilevel dynamical systems models to examine individual differences in the stability of daily attractions (stability, in these models, denotes the tendency for attractions to "self-correct" toward a person-specific setpoint over time). Women's attractions showed less day-to-day stability than men's, consistent with the notion of female sexual fluidity (i.e., heightened erotic sensitivity to situational and contextual influences). Yet, women did not recollect larger post-adolescent changes in sexual attractions than did men, and larger recollected post-adolescent changes did not predict lower day-to-day stability in the sample as a whole. Bisexually attracted individuals recollected larger post-adolescent changes in their attractions, and they showed lower day-to-day stability in attractions to their "less-preferred" gender, compared to individuals with exclusive same-sex or exclusive other-sex attractions. Our results suggest that both gender and bisexuality have independent influences on sexual fluidity, but these influences vary across short versus long timescales, and they also differ for attractions to one's "more-preferred" versus "less-preferred" gender.

  8. Sexual selection, sexual isolation and pheromones in Drosophila melanogaster strains after long-term maintaining on different diets.

    Science.gov (United States)

    Trajković, Jelena; Miličić, Dragana; Savić, Tatjana; Pavković-Lučić, Sofija

    2017-07-01

    Evolution of reproductive isolation may be a consequence of a variety of signals used in courtship and mate preferences. Pheromones play an important role in both sexual selection and sexual isolation. The abundance of pheromones in Drosophila melanogaster may depend on different environmental factors, including diet. The aim of this study was to ascertain to which degree principal pheromones affect sexual selection in D. melanogaster. We used D. melanogaster strains reared for 14 years on four substrates: standard cornmeal substrate and those containing tomato, banana and carrot. We have previously determined that long-term maintaining of these dietary strains resulted in differences in their cuticular hydrocarbons profile (CHs). In this work, we have tested the level of sexual selection and sexual isolation between aforementioned strains. We found that the high levels of cis-vaccenyl acetate, 7-pentacosene and 7,11-nonacosadiene in the strain reared on a substrate containing carrot affected the individual attractiveness and influenced sexual isolation between flies of this strain and flies reared on a substrate containing banana. Based on these results, long-term different diets, may contribute, to sexual behaviour of D. melanogaster via the effects of principal pheromones. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. The pathogen transmission avoidance theory of sexual selection

    Energy Technology Data Exchange (ETDEWEB)

    Loehle, C.

    1997-08-01

    The current theory that sexual selection results from female preference for males with good genes suffers from several problems. An alternative explanation, the pathogen transmission avoidance hypothesis, argues that the primary function of showy traits is to provide a reliable signal of current disease status, so that sick individuals can be avoided during mating. This study shows that a significant risk of pathogen transmission occurs during mating and that showy traits are reliable indicators of current disease status. The origin of female choosiness is argued to lie in a general tendency to avoid sick individuals, even in the absence of showy traits, which originate as exaggerations of normal traits that are indicative of good health (bright feathers, vigorous movement, large size). Thus, in this new model the origins of both showy traits and female choosiness are not problematic and there is no threshold effect. This model predicts that when the possession of male showy traits does not help to reduce disease in the female, showy traits are unlikely to occur. This case corresponds to thorough exposure of every animal to all group pathogens, on average, in large groups. Such species are shown with a large data set on birds to be less likely to exhibit showy traits. The good-genes model does not make this prediction. The pathogen transmission avoidance model can also lead to the evolution of showy traits even when selection is not effective against a given pathogen (e.g., when there is no heritable variation for resistance), but can result in selection for resistance if such genes are present. Monogamy is argued to reduce selection pressures for showy traits; data show monogamous species to be both less parasitized and less showy. In the context of reduction of pathogen transmission rates in showy populations, selection pressure becomes inversely frequency-dependent, which makes showy traits likely to be self-limiting rather than runaway.

  10. Kin selection versus sexual selection: why the ends do not meet

    DEFF Research Database (Denmark)

    Boomsma, Jacobus J

    2007-01-01

    non-social and cooperative breeding. Sexually selected traits in eusocial lineages are therefore peculiar, and their evolution constrained. Indirect (inclusive) fitness benefits in cooperatively breeding vertebrates appear to be negatively correlated with promiscuity, corroborating that kin selection......I redevelop the hypothesis that lifetime monogamy is a fundamental condition for the evolution of eusocial lineages with permanent non-reproductive castes, and that later elaborations--such as multiply-mated queens and multi-queen colonies--arose without the re-mating promiscuity that characterizes...

  11. Mate choice and sexual selection: what have we learned since Darwin?

    Science.gov (United States)

    Jones, Adam G; Ratterman, Nicholas L

    2009-06-16

    Charles Darwin laid the foundation for all modern work on sexual selection in his seminal book The Descent of Man, and Selection in Relation to Sex. In this work, Darwin fleshed out the mechanism of sexual selection, a hypothesis that he had proposed in The Origin of Species. He went well beyond a simple description of the phenomenon by providing extensive evidence and considering the far-reaching implications of the idea. Here we consider the contributions of Darwin to sexual selection with a particular eye on how far we have progressed in the last 150 years. We focus on 2 key questions in sexual selection. First, why does mate choice evolve at all? And second, what factors determine the strength of mate choice (or intensity of sexual selection) in each sex? Darwin provided partial answers to these questions, and the progress that has been made on both of these topics since his time should be seen as one of the great triumphs of modern evolutionary biology. However, a review of the literature shows that key aspects of sexual selection are still plagued by confusion and disagreement. Many of these areas are complex and will require new theory and empirical data for complete resolution. Overall, Darwin's contributions are still surprisingly relevant to the modern study of sexual selection, so students of evolutionary biology would be well advised to revisit his works. Although we have made significant progress in some areas of sexual selection research, we still have much to accomplish.

  12. Can sexual selection drive female life histories? A comparative study on Galliform birds

    OpenAIRE

    Kolm, N.; Stein, R. W.; Mooers, A. O.; Verspoor, J. J.; Cunningham, E. J. A.

    2007-01-01

    Sexual selection has been identified as a major evolutionary force shaping male life history traits but its impact on female life history evolution is less clear. Here we examine the impact of sexual selection on three key female traits (body size, egg size and clutch size) in Galliform birds. Using comparative independent contrast analyses and directional DISCRETE analyses, based on published data and a new genera-level supertree phylogeny of Galliform birds, we investigated how sexual selec...

  13. Sexual selection accounts for the geographic reversal of sexual size dimorphism in the dung fly, sepsis punctum (Diptera: Sepsidae).

    Science.gov (United States)

    Puniamoorthy, Nalini; Schäfer, Martin A; Blanckenhorn, Wolf U

    2012-07-01

    Sexual size dimorphism (SSD) varies widely across and within species. The differential equilibrium model of SSD explains dimorphism as the evolutionary outcome of consistent differences in natural and sexual selection between the sexes. Here, we comprehensively examine a unique cross-continental reversal in SSD in the dung fly, Sepsis punctum. Using common garden laboratory experiments, we establish that SSD is male-biased in Europe and female-biased in North America. When estimating sexual (pairing success) and fecundity selection (clutch size of female partner) on males under three operational sex ratios (OSRs), we find that the intensity of sexual selection is significantly stronger in European versus North American populations, increasing with male body size and OSR in the former only. Fecundity selection on female body size also increases strongly with egg number and weakly with egg volume, however, equally on both continents. Finally, viability selection on body size in terms of intrinsic (physiological) adult life span in the laboratory is overall nil and does not vary significantly across all seven populations. Although it is impossible to prove causality, our results confirm the differential equilibrium model of SSD in that differences in sexual selection intensity account for the reversal in SSD in European versus North American populations, presumably mediating the ongoing speciation process in S. punctum. © 2012 The Author(s).

  14. Sexual minorities and selection of a primary care physician in a midwestern U.S. city.

    Science.gov (United States)

    Labig, Chalmer E; Peterson, Tim O

    2006-01-01

    How and why sexual minorities select a primary care physician is critical to the development of methods for attracting these clients to a physician's practice. Data obtained from a sample of sexual minorities in a mid-size city in our nation's heartland would indicate that these patients are loyal when the primary care physician has a positive attitude toward their sexual orientation. The data also confirms that most sexual minorities select same sex physicians but not necessarily same sexual orientation physicians because of lack of knowledge of physicians' sexual orientation. Family practice physicians and other primary care physicians can reach out to this population by encouraging word of mouth advertising and by displaying literature on health issues for all sexual orientations in their offices.

  15. Optimal Parameter Selection of Power System Stabilizer using Genetic Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hyeng Hwan; Chung, Dong Il; Chung, Mun Kyu [Dong-AUniversity (Korea); Wang, Yong Peel [Canterbury Univeristy (New Zealand)

    1999-06-01

    In this paper, it is suggested that the selection method of optimal parameter of power system stabilizer (PSS) with robustness in low frequency oscillation for power system using real variable elitism genetic algorithm (RVEGA). The optimal parameters were selected in the case of power system stabilizer with one lead compensator, and two lead compensator. Also, the frequency responses characteristics of PSS, the system eigenvalues criterion and the dynamic characteristics were considered in the normal load and the heavy load, which proved usefulness of RVEGA compare with Yu's compensator design theory. (author). 20 refs., 15 figs., 8 tabs.

  16. The role of ecology in speciation by sexual selection: a systematic empirical review.

    Science.gov (United States)

    Scordato, Elizabeth S C; Symes, Laurel B; Mendelson, Tamra C; Safran, Rebecca J

    2014-01-01

    Theoretical and empirical research indicates that sexual selection interacts with the ecological context in which mate choice occurs, suggesting that sexual and natural selection act together during the evolution of premating reproductive isolation. However, the relative importance of natural and sexual selection to speciation remains poorly understood. Here, we applied a recent conceptual framework for examining interactions between mate choice divergence and ecological context to a review of the empirical literature on speciation by sexual selection. This framework defines two types of interactions between mate choice and ecology: internal interactions, wherein natural and sexual selection jointly influence divergence in sexual signal traits and preferences, and external interactions, wherein sexual selection alone acts on traits and preferences but ecological context shapes the transmission efficacy of sexual signals. The objectives of this synthesis were 3-fold: to summarize the traits, ecological factors, taxa, and geographic contexts involved in studies of mate choice divergence; to analyze patterns of association between these variables; and to identify the most common types of interactions between mate choice and ecological factors. Our analysis revealed that certain traits are consistently associated with certain ecological factors. Moreover, among studies that examined a divergent sexually selected trait and an ecological factor, internal interactions were more common than external interactions. Trait-preference associations may thus frequently be subject to both sexual and natural selection in cases of divergent mate choice. Our results highlight the importance of interactions between sexual selection and ecology in mate choice divergence and suggest areas for future research. © The American Genetic Association. 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  17. Evidence of directional and stabilizing selection in contemporary humans.

    Science.gov (United States)

    Sanjak, Jaleal S; Sidorenko, Julia; Robinson, Matthew R; Thornton, Kevin R; Visscher, Peter M

    2018-01-02

    Modern molecular genetic datasets, primarily collected to study the biology of human health and disease, can be used to directly measure the action of natural selection and reveal important features of contemporary human evolution. Here we leverage the UK Biobank data to test for the presence of linear and nonlinear natural selection in a contemporary population of the United Kingdom. We obtain phenotypic and genetic evidence consistent with the action of linear/directional selection. Phenotypic evidence suggests that stabilizing selection, which acts to reduce variance in the population without necessarily modifying the population mean, is widespread and relatively weak in comparison with estimates from other species.

  18. Conflict Resolution Styles as Mediators of Female Child Sexual Abuse Experience and Heterosexual Couple Relationship Satisfaction and Stability in Adulthood.

    Science.gov (United States)

    Knapp, Ashlee E; Knapp, Darin J; Brown, Cameron C; Larson, Jeffry H

    2017-01-01

    Trauma from female incestuous child sexual abuse may result in negative psychological consequences affecting adult relationships. This study explored relational consequences of incestuous child sexual abuse, focusing on conflict resolution styles, relationship satisfaction, and relationship stability. Using the RELATionship Evaluation dataset, 457 heterosexual couples in which female partners experienced incestuous child sexual abuse were compared to a group of 1,827 couples with no sexual abuse history. Analyses tested differences in the frequencies of reported conflict resolution styles for incestuous child sexual abuse and non-incestuous child sexual abuse groups, the mediating effects of conflict resolution styles on the relationship between incestuous child sexual abuse, and self- and partner-reported relationship satisfaction and stability. Significant differences in the reports of types of conflict resolution styles were found for incestuous child sexual abuse versus non-incestuous child sexual abuse groups. Incestuous child sexual abuse and conflict resolution styles were negatively related to relationship satisfaction and stability and there was a significant indirect effect between female incestuous child sexual abuse, female volatility, and relationship instability. Clinical applications for couple relationships are discussed.

  19. Selective Electrocatalytic Activity of Ligand Stabilized Copper Oxide Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kauffman, Douglas R; Ohodnicki, Paul R; Kail, Brian W; Matranga, Christopher

    2011-01-01

    Ligand stabilization can influence the surface chemistry of Cu oxide nanoparticles (NPs) and provide unique product distributions for electrocatalytic methanol (MeOH) oxidation and CO{sub 2} reduction reactions. Oleic acid (OA) stabilized Cu{sub 2}O and CuO NPs promote the MeOH oxidation reaction with 88% and 99.97% selective HCOH formation, respectively. Alternatively, CO{sub 2} is the only reaction product detected for bulk Cu oxides and Cu oxide NPs with no ligands or weakly interacting ligands. We also demonstrate that OA stabilized Cu oxide NPs can reduce CO{sub 2} into CO with a {approx}1.7-fold increase in CO/H{sub 2} production ratios compared to bulk Cu oxides. The OA stabilized Cu oxide NPs also show 7.6 and 9.1-fold increases in CO/H{sub 2} production ratios compared to weakly stabilized and non-stabilized Cu oxide NPs, respectively. Our data illustrates that the presence and type of surface ligand can substantially influence the catalytic product selectivity of Cu oxide NPs.

  20. Sexual selection as a consequence of pathogen avoidance behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Loehle, C. [Argonne National Lab., IL (United States); Logofet, D.O. [Russian Academy of Sciences, Moscow (Russian Federation). Laboratory of Mathematical Ecology

    1997-08-01

    The current theory that sexual selection results from female choice for good genes suffers from several problems. An alternative explanation is proposed. The pathogen avoidance hypothesis argues that the primary function of showy traits is to provide a reliable signal of current disease status so that sick individuals may be avoided during mating. Our studies shown that a significant risk of pathogen transmission occurs during mating and that showy traits are reliable indicators of current disease status. The origin of female choosiness is argued to lie in a general tendency to avoid sick individuals, even in the absence of showy traits. The showy traits are argued to originate as simple exaggerations of normal traits that are indicative of good health (bright feathers; vigorous movement; large size). Thus the origins of both showy traits and female choosiness are not problematic in this theory. A game theory analysis is employed to formalize the theory. Results of the game theory model support the theory. In particular, when the possession of male showy traits does not help reduce disease in the female, then showy traits are unlikely to occur. This case corresponds to the situation in large flocks or herds in which every animal is thoroughly exposed to all group pathogens on average. Such species do not exhibit showy traits. The good genes model does not make this prediction. The pathogen avoidance model can also lead to the evolution of showy traits even when selection is not effective against a given pathogen (e.g., when there is no heritable variation for resistance) but will lead to selection for resistance if such genes are present. Overall, the pathogen avoidance hypothesis provides a complete alternative to the good genes theory.

  1. Yield evaluation and stability analysis in newly selected `KSA' cotton ...

    African Journals Online (AJOL)

    Yield evaluation and stability analysis in newly selected `KSA' cotton cultivars in Western Kenya. R M Opondo, G A Ombakho. Abstract. (African Crop Science Journal, 1997 5(2): 119-126). http://dx.doi.org/10.4314/acsj.v5i2.27854 · AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians ...

  2. Sexual selection and the rodent baculum: an intraspecific study in the house mouse (Mus musculus domesticus).

    Science.gov (United States)

    Ramm, Steven A; Khoo, Lin; Stockley, Paula

    2010-01-01

    The rapid divergence of genitalia is a pervasive trend in animal evolution, thought to be due to the action of sexual selection. To test predictions from the sexual selection hypothesis, we here report data on the allometry, variation, plasticity and condition dependence of baculum morphology in the house mouse (Mus musculus domesticus). We find that that baculum size: (a) exhibits no consistent pattern of allometric scaling (baculum size being in most cases unrelated to body size), (b) exhibits low to moderate levels of phenotypic variation, (c) does not exhibit phenotypic plasticity in response to differences in perceived levels of sexual competition and (d) exhibits limited evidence of condition dependence. These patterns provide only limited evidence in support of the sexual selection hypothesis, and no consistent support for any particular sexual selection mechanism; however, more direct measures of how genital morphology influences male fertilization success are required.

  3. Generalized structural equations improve sexual-selection analyses.

    Directory of Open Access Journals (Sweden)

    Sonia Lombardi

    Full Text Available Sexual selection is an intense evolutionary force, which operates through competition for the access to breeding resources. There are many cases where male copulatory success is highly asymmetric, and few males are able to sire most females. Two main hypotheses were proposed to explain this asymmetry: "female choice" and "male dominance". The literature reports contrasting results. This variability may reflect actual differences among studied populations, but it may also be generated by methodological differences and statistical shortcomings in data analysis. A review of the statistical methods used so far in lek studies, shows a prevalence of Linear Models (LM and Generalized Linear Models (GLM which may be affected by problems in inferring cause-effect relationships; multi-collinearity among explanatory variables and erroneous handling of non-normal and non-continuous distributions of the response variable. In lek breeding, selective pressure is maximal, because large numbers of males and females congregate in small arenas. We used a dataset on lekking fallow deer (Dama dama, to contrast the methods and procedures employed so far, and we propose a novel approach based on Generalized Structural Equations Models (GSEMs. GSEMs combine the power and flexibility of both SEM and GLM in a unified modeling framework. We showed that LMs fail to identify several important predictors of male copulatory success and yields very imprecise parameter estimates. Minor variations in data transformation yield wide changes in results and the method appears unreliable. GLMs improved the analysis, but GSEMs provided better results, because the use of latent variables decreases the impact of measurement errors. Using GSEMs, we were able to test contrasting hypotheses and calculate both direct and indirect effects, and we reached a high precision of the estimates, which implies a high predictive ability. In synthesis, we recommend the use of GSEMs in studies on

  4. Do extra-group fertilizations increase the potential for sexual selection in male mammals?

    Science.gov (United States)

    Isvaran, Kavita; Sankaran, Sumithra

    2017-10-01

    Fertilizations by males outside the social breeding group (extra-group paternity, EGP) are widespread in birds and mammals. EGP is generally proposed to increase male reproductive skew and thereby increase the potential for sexual selection, but the generality of this relationship is unclear. We extracted data from 27 mammals in seven orders and used phylogenetic comparative methods to investigate the influence of EGP and social mating system on measures of inequality in male fertilization success, which are indices of the potential for sexual selection. We find that EGP and social mating system can predict the potential for sexual selection in mammalian populations, but only when considered jointly and not individually. EGP appears to increase the potential for sexual selection but only when the degree of social polygyny is relatively low. When social polygyny is high, EGP appears to result in a more uniform distribution of reproduction and a decrease in the potential for sexual selection. A possible explanation to be investigated is that the phenotype of extra-group fathers differs systematically across social mating systems. Our findings have implications for the use of EGP and social mating system as indices of sexual selection in comparative analyses of trait evolution under sexual selection. © 2017 The Author(s).

  5. Sexual selection on spontaneous mutations strengthens the between-sex genetic correlation for fitness.

    Science.gov (United States)

    Allen, Scott L; McGuigan, Katrina; Connallon, Tim; Blows, Mark W; Chenoweth, Stephen F

    2017-10-01

    A proposed benefit to sexual selection is that it promotes purging of deleterious mutations from populations. For this benefit to be realized, sexual selection, which is usually stronger on males, must purge mutations deleterious to both sexes. Here, we experimentally test the hypothesis that sexual selection on males purges deleterious mutations that affect both male and female fitness. We measured male and female fitness in two panels of spontaneous mutation-accumulation lines of the fly, Drosophila serrata, each established from a common ancestor. One panel of mutation accumulation lines limited both natural and sexual selection (LS lines), whereas the other panel limited natural selection, but allowed sexual selection to operate (SS lines). Although mutation accumulation caused a significant reduction in male and female fitness in both the LS and SS lines, sexual selection had no detectable effect on the extent of the fitness reduction. Similarly, despite evidence of mutational variance for fitness in males and females of both treatments, sexual selection had no significant impact on the amount of mutational genetic variance for fitness. However, sexual selection did reshape the between-sex correlation for fitness: significantly strengthening it in the SS lines. After 25 generations, the between-sex correlation for fitness was positive but considerably less than one in the LS lines, suggesting that, although most mutations had sexually concordant fitness effects, sex-limited, and/or sex-biased mutations contributed substantially to the mutational variance. In the SS lines this correlation was strong and could not be distinguished from unity. Individual-based simulations that mimick the experimental setup reveal two conditions that may drive our results: (1) a modest-to-large fraction of mutations have sex-limited (or highly sex-biased) fitness effects, and (2) the average fitness effect of sex-limited mutations is larger than the average fitness effect of

  6. Stability of Self-Reported Arousal to Sexual Fantasies Involving Children in a Clinical Sample of Pedophiles and Hebephiles.

    Science.gov (United States)

    Grundmann, Dorit; Krupp, Jurian; Scherner, Gerold; Amelung, Till; Beier, Klaus M

    2016-07-01

    In forensic research, there is a controversial discussion concerning the changeability or stability of pedophilia. Seto (2012) conceptualized pedophilia as a sexual age orientation characterized by an early onset, correlations with sexual and romantic behavior, and stability over time. However, empirical data are sparse and are mostly based on samples of detected offenders. The present study examined self-reported arousal to sexual fantasies involving children in a clinical sample of pedo-/hebephiles. In Study 1, retrospective self-reports on the age of onset and duration of sexual interest in minors were examined. In Study 2, the stability and variability of self-reported arousal to sexual fantasies involving children were evaluated prospectively. Non-prosecuted self-identifying pedo-/hebephilic men seeking professional help were recruited within the Berlin Prevention Project Dunkelfeld. Between 2005 and 2013, 494 participants completed the intake assessment. Self-reported data were collected via questionnaire focusing on sexual arousal to fantasies during masturbation involving prepubescent and/or early pubescent minors. Subsequent assessments of sexual arousal were obtained for 121 of the participants. The average time between the first and last assessment was approximately 29 months. Spearman's correlation coefficients examined the between-group rank-order and Wilcoxon signed-rank tests examined the within-individual mean-level stability. The majority of subjects reported an early onset of their pedo-/hebephilic sexual arousal. The rank-order stability was medium to high. Over the investigated period, the majority of subjects showed no or only minimal decrease or increase of self-reported sexual arousal. These results suggested that sexual arousal to fantasies involving prepubescent and/or early pubescent children is stable. Furthermore, the results support the conceptualization of pedo-/hebephilia as a sexual age orientation in men.

  7. No Evidence for Pre-Copulatory Sexual Selection on Sperm Length in a Passerine Bird

    Science.gov (United States)

    Lifjeld, Jan T.; Laskemoen, Terje; Kleven, Oddmund; Pedersen, A. Tiril M.; Lampe, Helene M.; Rudolfsen, Geir; Schmoll, Tim; Slagsvold, Tore

    2012-01-01

    There is growing evidence that post-copulatory sexual selection, mediated by sperm competition, influences the evolution of sperm phenotypes. Evidence for pre-copulatory sexual selection effects on sperm traits, on the other hand, is rather scarce. A recent paper on the pied flycatcher, Ficedula hypoleuca, reported phenotypic associations between sperm length and two sexually selected male traits, i.e. plumage colour and arrival date, thus invoking pre-copulatory sexual selection for longer sperm. We were unable to replicate these associations with a larger data set from the same and two additional study populations; sperm length was not significantly related to either male plumage colour or arrival date. Furthermore, there was no significant difference in sperm length between populations despite marked differences in male plumage colour. We also found some evidence against the previously held assumption of longer sperm being qualitatively superior; longer sperm swam at the same speed as shorter sperm, but were less able to maintain speed over time. We argue that both empirical evidence and theoretical considerations suggest that the evolution of sperm morphology is not primarily associated with pre-copulatory sexual selection on male secondary sexual traits in this or other passerine bird species. The relatively large between-male variation in sperm length in this species is probably due to relaxed post-copulatory sexual selection. PMID:22384277

  8. No evidence for pre-copulatory sexual selection on sperm length in a passerine bird.

    Directory of Open Access Journals (Sweden)

    Jan T Lifjeld

    Full Text Available There is growing evidence that post-copulatory sexual selection, mediated by sperm competition, influences the evolution of sperm phenotypes. Evidence for pre-copulatory sexual selection effects on sperm traits, on the other hand, is rather scarce. A recent paper on the pied flycatcher, Ficedula hypoleuca, reported phenotypic associations between sperm length and two sexually selected male traits, i.e. plumage colour and arrival date, thus invoking pre-copulatory sexual selection for longer sperm. We were unable to replicate these associations with a larger data set from the same and two additional study populations; sperm length was not significantly related to either male plumage colour or arrival date. Furthermore, there was no significant difference in sperm length between populations despite marked differences in male plumage colour. We also found some evidence against the previously held assumption of longer sperm being qualitatively superior; longer sperm swam at the same speed as shorter sperm, but were less able to maintain speed over time. We argue that both empirical evidence and theoretical considerations suggest that the evolution of sperm morphology is not primarily associated with pre-copulatory sexual selection on male secondary sexual traits in this or other passerine bird species. The relatively large between-male variation in sperm length in this species is probably due to relaxed post-copulatory sexual selection.

  9. The geography of sex-specific selection, local adaptation, and sexual dimorphism.

    Science.gov (United States)

    Connallon, Tim

    2015-09-01

    Local adaptation and sexual dimorphism are iconic evolutionary scenarios of intraspecific adaptive differentiation in the face of gene flow. Although theory has traditionally considered local adaptation and sexual dimorphism as conceptually distinct processes, emerging data suggest that they often act concurrently during evolutionary diversification. Here, I merge theories of local adaptation in space and sex-specific adaptation over time, and show that their confluence yields several new predictions about the roles of context-specific selection, migration, and genetic correlations, in adaptive diversification. I specifically revisit two influential predictions from classical studies of clinal adaptation and sexual dimorphism: (1) that local adaptation should decrease with distance from the species' range center and (2) that opposing directional selection between the sexes (sexual antagonism) should inevitably accompany the evolution of sexual dimorphism. I show that both predictions can break down under clinally varying selection. First, the geography of local adaptation can be sexually dimorphic, with locations of relatively high local adaptation differing profoundly between the sexes. Second, the intensity of sexual antagonism varies across the species' range, with subpopulations near the range center representing hotspots for antagonistic selection. The results highlight the context-dependent roles of migration versus sexual conflict as primary constraints to adaptive diversification. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  10. Selective Serotonin Reuptake Inhibitor-Induced Sexual Dysfunction in Adolescents: A Review.

    Science.gov (United States)

    Scharko, Alexander M.

    2004-01-01

    Objective: To review the existing literature on selective serotonin reuptake inhibitor (SSRI)-induced sexual dysfunction in adolescents. Method: A literature review of SSRI-induced adverse effects in adolescents focusing on sexual dysfunction was done. Nonsexual SSRI-induced adverse effects were compared in adult and pediatric populations.…

  11. Sexual Selection on male cuticular hydrocarbons via male-male competition and female choice.

    Science.gov (United States)

    Lane, S M; Dickinson, A W; Tregenza, T; House, C M

    2016-07-01

    Traditional views of sexual selection assumed that male-male competition and female mate choice work in harmony, selecting upon the same traits in the same direction. However, we now know that this is not always the case and that these two mechanisms often impose conflicting selection on male sexual traits. Cuticular hydrocarbons (CHCs) have been shown to be linked to both social dominance and male attractiveness in several insect species. However, although several studies have estimated the strength and form of sexual selection imposed on male CHCs by female mate choice, none have established whether these chemical traits are also subject to sexual selection via male-male competition. Using a multivariate selection analysis, we estimate and compare sexual selection exerted by male-male competition and female mate choice on male CHC composition in the broad-horned flour beetle Gnatocerus cornutus. We show that male-male competition exerts strong linear selection on both overall CHC abundance and body size in males, while female mate choice exerts a mixture of linear and nonlinear selection, targeting not just the overall amount of CHCs expressed but the relative abundance of specific hydrocarbons as well. We discuss the potential implications of this antagonistic selection with regard to male reproductive success. © 2016 The Authors. Journal of Evolutionary Biology published by John Wiley & Sons Ltd on behalf of European Society for Evolutionary Biology.

  12. Sexual Selection and the differences between the sexes in Mandrills (Mandrillus sphinx).

    Science.gov (United States)

    Setchell, Joanna M

    2016-01-01

    Sexual selection has become a major focus in evolutionary and behavioral ecology. It is also a popular research topic in primatology. I use studies of mandrills (Mandrillus sphinx), a classic example of extravagant armaments and ornaments in animals, to exemplify how a long-term, multidisciplinary approach that integrates field observations with laboratory methods can contribute to on-going theoretical debates in the field of sexual selection. I begin with a brief summary of the main concepts of sexual selection theory and the differences between the sexes. I then introduce mandrills and the study population and review mandrill life history, the ontogeny of sex differences, and maternal effects. Next, I focus on male-male competition and female choice, followed by the less well-studied questions of female-female competition and male choice. This review shows how different reproductive priorities lead to very different life histories and divergent adaptations in males and females. It demonstrates how broadening traditional perspectives on sexual selection beyond the ostentatious results of intense sexual selection on males leads to an understanding of more subtle and cryptic forms of competition and choice in both sexes and opens many productive avenues in the study of primate reproductive strategies. These include the potential for studies of postcopulatory selection, female intrasexual competition, and male choice. These studies of mandrills provide comparison and, I hope, inspiration for studies of both other polygynandrous species and species with mating systems less traditionally associated with sexual selection. © 2016 Wiley Periodicals, Inc.

  13. Testing for a genetic response to sexual selection in a wild Drosophila population.

    Science.gov (United States)

    Gosden, T P; Thomson, J R; Blows, M W; Schaul, A; Chenoweth, S F

    2016-06-01

    In accordance with the consensus that sexual selection is responsible for the rapid evolution of display traits on macroevolutionary scales, microevolutionary studies suggest sexual selection is a widespread and often strong form of directional selection in nature. However, empirical evidence for the contemporary evolution of sexually selected traits via sexual rather than natural selection remains weak. In this study, we used a novel application of quantitative genetic breeding designs to test for a genetic response to sexual selection on eight chemical display traits from a field population of the fly, Drosophila serrata. Using our quantitative genetic approach, we were able to detect a genetically based difference in means between groups of males descended from fathers who had either successfully sired offspring or were randomly collected from the same wild population for one of these display traits, the diene (Z,Z)-5,9-C27 : 2 . Our experimental results, in combination with previous laboratory studies on this system, suggest that both natural and sexual selection may be influencing the evolutionary trajectories of these traits in nature, limiting the capacity for a contemporary evolutionary response. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  14. Sexual Selection Revisited ? Towards a Gender-Neutral Theory and Practice

    OpenAIRE

    2007-01-01

    Abstract In a recent issue of this journal, Vandermassen suggested that feminists should include sexual selection theory and evolutionary psychology in a unifying theory of human nature. In response, this article aims to offer some insight into the development of sexual selection theory, to caution against Vandermassen's unreserved assimilation and to promote the opposite ongoing integration ? an inclusion of gender perspectives into evolutionary biology. In society today, opinions...

  15. Social polyandry, parental investment, sexual selection, and evolution of reduced female gamete size.

    Science.gov (United States)

    Andersson, Malte

    2004-01-01

    Sexual selection in the form of sperm competition is a major explanation for small size of male gametes. Can sexual selection in polyandrous species with reversed sex roles also lead to reduced female gamete size? Comparative studies show that egg size in birds tends to decrease as a lineage evolves social polyandry. Here, a quantitative genetic model predicts that female scrambles over mates lead to evolution of reduced female gamete size. Increased female mating success drives the evolution of smaller eggs, which take less time to produce, until balanced by lowered offspring survival. Mean egg size is usually reduced and polyandry increased by increasing sex ratio (male bias) and maximum possible number of mates. Polyandry also increases with the asynchrony (variance) in female breeding start. Opportunity for sexual selection increases with the maximum number of mates but decreases with increasing sex ratio. It is well known that parental investment can affect sexual selection. The model suggests that the influence is mutual: owing to a coevolutionary feedback loop, sexual selection in females also shapes initial parental investment by reducing egg size. Feedback between sexual selection and parental investment may be common.

  16. Synchronization stability and pattern selection in a memristive neuronal network.

    Science.gov (United States)

    Wang, Chunni; Lv, Mi; Alsaedi, Ahmed; Ma, Jun

    2017-11-01

    Spatial pattern formation and selection depend on the intrinsic self-organization and cooperation between nodes in spatiotemporal systems. Based on a memory neuron model, a regular network with electromagnetic induction is proposed to investigate the synchronization and pattern selection. In our model, the memristor is used to bridge the coupling between the magnetic flux and the membrane potential, and the induction current results from the time-varying electromagnetic field contributed by the exchange of ion currents and the distribution of charged ions. The statistical factor of synchronization predicts the transition of synchronization and pattern stability. The bifurcation analysis of the sampled time series for the membrane potential reveals the mode transition in electrical activity and pattern selection. A formation mechanism is outlined to account for the emergence of target waves. Although an external stimulus is imposed on each neuron uniformly, the diversity in the magnetic flux and the induction current leads to emergence of target waves in the studied network.

  17. Synchronization stability and pattern selection in a memristive neuronal network

    Science.gov (United States)

    Wang, Chunni; Lv, Mi; Alsaedi, Ahmed; Ma, Jun

    2017-11-01

    Spatial pattern formation and selection depend on the intrinsic self-organization and cooperation between nodes in spatiotemporal systems. Based on a memory neuron model, a regular network with electromagnetic induction is proposed to investigate the synchronization and pattern selection. In our model, the memristor is used to bridge the coupling between the magnetic flux and the membrane potential, and the induction current results from the time-varying electromagnetic field contributed by the exchange of ion currents and the distribution of charged ions. The statistical factor of synchronization predicts the transition of synchronization and pattern stability. The bifurcation analysis of the sampled time series for the membrane potential reveals the mode transition in electrical activity and pattern selection. A formation mechanism is outlined to account for the emergence of target waves. Although an external stimulus is imposed on each neuron uniformly, the diversity in the magnetic flux and the induction current leads to emergence of target waves in the studied network.

  18. Trilobite spines and beetle horns: sexual selection in the Palaeozoic?

    Science.gov (United States)

    Knell, Robert J; Fortey, Richard A

    2005-06-22

    Raphiophorid trilobites commonly bore median cephalic protuberances such as spines or bulbs, showing a remarkable variety of form. It is unlikely that their primary function was for protection or in hydrodynamics. A case is made that they were secondary sexual features, by comparison with similar morphological structures developed on rhinoceros beetles and other arthropods. This interpretation is supported by four lines of evidence: their ontogeny, their diversity, the existence of plausible examples of sexual dimorphs in some cases and the fact that they show positive allometry.

  19. Stronger sexual selection in warmer waters: the case of a sex role reversed pipefish.

    Directory of Open Access Journals (Sweden)

    Nuno M Monteiro

    Full Text Available In order to answer broader questions about sexual selection, one needs to measure selection on a wide array of phenotypic traits, simultaneously through space and time. Nevertheless, studies that simultaneously address temporal and spatial variation in reproduction are scarce. Here, we aimed to investigate the reproductive dynamics of a cold-water pipefish simultaneously through time (encompassing variation within each breeding cycle and as individuals grow and space (by contrasting populations experiencing distinct water temperature regimes in order to test hypothesized differences in sexual selection. Even though the sampled populations inhabited locations with very different water temperature regimes, they exhibited considerable similarities in reproductive parameters. The most striking was the existence of a well-defined substructure in reproductive activity, where larger individuals reproduce for longer periods, which seemed dependent on a high temperature threshold for breeding rather than on the low temperatures that vary heavily according to latitude. Furthermore, the perceived disparities among populations, such as size at first reproduction, female reproductive investment, or degree of sexual size dimorphism, seemed dependent on the interplay between seawater temperature and the operational sex ratio (OSR. Contrary to our expectations of an enhanced opportunity for sexual selection in the north, we found the opposite: higher female reproductive investment coupled with increased sexual size dimorphism in warmer waters, implying that a prolonged breeding season does not necessarily translate into reduced sexual selection pressure. In fact, if the limited sex has the ability to reproduce either continuously or recurrently during the entire breeding season, an increased opportunity for sexual selection might arise from the need to compete for available partners under strongly biased OSRs across protracted breeding seasons. A more general

  20. Qualitative evaluation of selected social factors that impact sexual ...

    African Journals Online (AJOL)

    Objectives: This study was designed to explore the sexual behaviour of students in a metropolitan Durban University of Technology in KwaZulu-Natal to understand the social factors underlying their risk of HIV infection. Methods: This is a qualitative study that used cluster sampling where the population was stratified by ...

  1. Sex in murky waters: algal-induced turbidity increases sexual selection in pipefish.

    Science.gov (United States)

    Sundin, Josefin; Aronsen, Tonje; Rosenqvist, Gunilla; Berglund, Anders

    2017-01-01

    Algal-induced turbidity has been shown to alter several important aspects of reproduction and sexual selection. However, while turbidity has been shown to negatively affect reproduction and sexually selected traits in some species, it may instead enhance reproductive success in others, implying that the impact of eutrophication is far more complex than originally believed. In this study, we aimed to provide more insight into these inconsistent findings. We used molecular tools to investigate the impact of algal turbidity on reproductive success and sexual selection on males in controlled laboratory experiments, allowing mate choice, mating competition, and mate encounter rates to affect reproduction. As study species, we used the broad-nosed pipefish, Syngnathus typhle , a species practicing male pregnancy and where we have previously shown that male mate choice is impaired by turbidity. Here, turbidity instead enhanced sexual selection on male size and mating success as well as reproductive success. Effects from mating competition and mate encounter rates may thus override effects from mate choice based on visual cues, producing an overall stronger sexual selection in turbid waters. Hence, seemingly inconsistent effects of turbidity on sexual selection may depend on which mechanisms of sexual selection that have been under study. Algal blooms are becoming increasingly more common due to eutrophication of freshwater and marine environments. The high density of algae lowers water transparency and reduces the possibility for fish and other aquatic animals to perform behaviors dependent on vision. We have previously shown that pipefish are unable to select the best partner in mate choice trials when water transparency was reduced. However, fish might use other senses than vision to compensate for the reduction in water transparency. In this study, we found that when fish were allowed to freely interact, thereby allowing competition between partners and direct contact

  2. Sexual selection predicts advancement of avian spring migration in response to climate change

    DEFF Research Database (Denmark)

    Spottiswoode, Claire N; Tøttrup, Anders P; Coppack, Timothy

    2006-01-01

    Global warming has led to earlier spring arrival of migratory birds, but the extent of this advancement varies greatly among species, and it remains uncertain to what degree these changes are phenotypically plastic responses or microevolutionary adaptations to changing environmental conditions. We...... suggest that sexual selection could help to understand this variation, since early spring arrival of males is favoured by female choice. Climate change could weaken the strength of natural selection opposing sexual selection for early migration, which would predict greatest advancement in species...... in the timing of first-arriving individuals, suggesting that selection has not only acted on protandrous males. These results suggest that sexual selection may have an impact on the responses of organisms to climate change, and knowledge of a species' mating system might help to inform attempts at predicting...

  3. Exposure to sexualized media content and selective attention for sexual cues: An experimental study

    NARCIS (Netherlands)

    Doornwaard, Suzan; van den Eijnden, Regina; Johnson, Adam; ter Bogt, Tom

    2014-01-01

    This study examined whether exposure to sexualized media influences the subconscious process of attention allocation to subsequently encountered stimuli. One hundred twenty-three participants (61 females) between 18-23 years (M age = 19.99 years) watched a 3-minute video clip containing either

  4. Optimal Subinterval Selection Approach for Power System Transient Stability Simulation

    Directory of Open Access Journals (Sweden)

    Soobae Kim

    2015-10-01

    Full Text Available Power system transient stability analysis requires an appropriate integration time step to avoid numerical instability as well as to reduce computational demands. For fast system dynamics, which vary more rapidly than what the time step covers, a fraction of the time step, called a subinterval, is used. However, the optimal value of this subinterval is not easily determined because the analysis of the system dynamics might be required. This selection is usually made from engineering experiences, and perhaps trial and error. This paper proposes an optimal subinterval selection approach for power system transient stability analysis, which is based on modal analysis using a single machine infinite bus (SMIB system. Fast system dynamics are identified with the modal analysis and the SMIB system is used focusing on fast local modes. An appropriate subinterval time step from the proposed approach can reduce computational burden and achieve accurate simulation responses as well. The performance of the proposed method is demonstrated with the GSO 37-bus system.

  5. Meiotic drive influences the outcome of sexually antagonistic selection at a linked locus.

    Science.gov (United States)

    Patten, M M

    2014-11-01

    Most meiotic drivers, such as the t-haplotype in Mus and the segregation distorter (SD) in Drosophila, act in a sex-specific manner, gaining a transmission advantage through one sex although suffering only the fitness costs associated with the driver in the other. Their inheritance is thus more likely through one of the two sexes, a property they share with sexually antagonistic alleles. Previous theory has shown that pairs of linked loci segregating for sexually antagonistic alleles are more likely to remain polymorphic and that linkage disequilibrium accrues between them. I probe this similarity between drive and sexual antagonism and examine the evolution of chromosomes experiencing these selection pressures simultaneously. Reminiscent of previous theory, I find that: the opportunity for polymorphism increases for a sexually antagonistic locus that is physically linked to a driving locus; the opportunity for polymorphism at a driving locus also increases when linked to a sexually antagonistic locus; and stable linkage disequilibrium accompanies any polymorphic equilibrium. Additionally, I find that drive at a linked locus favours the fixation of sexually antagonistic alleles that benefit the sex in which drive occurs. Further, I show that under certain conditions reduced recombination between these two loci is selectively favoured. These theoretical results provide clear, testable predictions about the nature of sexually antagonistic variation on driving chromosomes and have implications for the evolution of genomic architecture. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

  6. The Role of Sexual Selection in the Evolution of Chemical Signals in Insects

    Directory of Open Access Journals (Sweden)

    Sandra Steiger

    2014-06-01

    Full Text Available Chemical communication is the most ancient and widespread form of communication. Yet we are only beginning to grasp the complexity of chemical signals and the role they play in sexual selection. Focusing on insects, we review here the recent progress in the field of olfactory-based sexual selection. We will show that there is mounting empirical evidence that sexual selection affects the evolution of chemical traits, but form and strength of selection differ between species. Studies indicate that some chemical signals are expressed in relation to an individual’s condition and depend, for example, on age, immunocompetence, fertility, body size or degree of inbreeding. Males or females might benefit by choosing based on those traits, gaining resources or “good genes”. Other chemical traits appear to reliably reflect an individual’s underlying genotype and are suitable to choose a mating partner that matches best the own genotype.

  7. The sight of the peacock's tail makes me sick: the early arguments on sexual selection.

    Science.gov (United States)

    Hiraiwa-Hasegawa, M

    2000-03-01

    Why does a peacock have a beautiful train, while a peahen is sober without such flamboyance? Darwin proposed the theory of sexual selection to explain the differences between the sexes of the same species. Recently the study of sexual selection has been one of the most flourishing areas in evolutionary biology. However, the theory met with great resistance from biologists since the publication of the idea and the history of the theory included a lot of misunderstanding and confusion. There are several reasons for this. First, classical Darwinism failed to recognize social competition as an important selective force. Second, the good-for-the-species argument, which persisted in the days after Darwin, made the sexual selection argument more difficult to under-stand. Compared to the discussions on animals, Darwin's argument on human sex differences is not satisfactory. The reason probably lies in the debate over human racial differences which prevailed in the 19th century.

  8. Can sexual selection drive female life histories? A comparative study on Galliform birds.

    Science.gov (United States)

    Kolm, N; Stein, R W; Mooers, A Ø; Verspoor, J J; Cunningham, E J A

    2007-03-01

    Sexual selection has been identified as a major evolutionary force shaping male life history traits but its impact on female life history evolution is less clear. Here we examine the impact of sexual selection on three key female traits (body size, egg size and clutch size) in Galliform birds. Using comparative independent contrast analyses and directional discrete analyses, based on published data and a new genera-level supertree phylogeny of Galliform birds, we investigated how sexual selection [quantified as sexual size dimorphism (SSD) and social mating system (MS)] affects these three important female traits. We found that female body mass was strongly and positively correlated with egg size but not with clutch size, and that clutch size decreased as egg size increased. We established that SSD was related to MS, and then used SSD as a proxy of the strength of sexual selection. We found both a positive relationship between SSD and female body mass and egg size and that increases in female body mass and egg size tend to occur following increases in SSD in this bird order. This pattern of female body mass increases lagging behind changes in SSD, established using our directional discrete analysis, suggests that female body mass increases as a response to increases in the level of sexual selection and not simply through a strong genetic relationship with male body mass. This suggests that sexual selection is linked to changes in female life history traits in Galliformes and we discuss how this link may shape patterns of life history variation among species.

  9. Natural and sexual selection giveth and taketh away reproductive barriers: models of population divergence in guppies.

    Science.gov (United States)

    Labonne, Jacques; Hendry, Andrew P

    2010-07-01

    The standard predictions of ecological speciation might be nuanced by the interaction between natural and sexual selection. We investigated this hypothesis with an individual-based model tailored to the biology of guppies (Poecilia reticulata). We specifically modeled the situation where a high-predation population below a waterfall colonizes a low-predation population above a waterfall. Focusing on the evolution of male color, we confirm that divergent selection causes the appreciable evolution of male color within 20 generations. The rate and magnitude of this divergence were reduced when dispersal rates were high and when female choice did not differ between environments. Adaptive divergence was always coupled to the evolution of two reproductive barriers: viability selection against immigrants and hybrids. Different types of sexual selection, however, led to contrasting results for another potential reproductive barrier: mating success of immigrants. In some cases, the effects of natural and sexual selection offset each other, leading to no overall reproductive isolation despite strong adaptive divergence. Sexual selection acting through female choice can thus strongly modify the effects of divergent natural selection and thereby alter the standard predictions of ecological speciation. We also found that under no circumstances did divergent selection cause appreciable divergence in neutral genetic markers.

  10. Sex-ratio control erodes sexual selection, revealing evolutionary feedback from adaptive plasticity

    NARCIS (Netherlands)

    Fawcett, Tim W.; Kuijper, Bram; Weissing, Franz J.; Pen, Ido

    2011-01-01

    Female choice is a powerful selective force, driving the elaboration of conspicuous male ornaments. This process of sexual selection has profound implications for many life-history decisions, including sex allocation. For example, females with attractive partners should produce more sons, because

  11. Phenotypic differentiation is associated with divergent sexual selection among closely related barn swallow populations

    Czech Academy of Sciences Publication Activity Database

    Wilkins, M. R.; Karaardic, H.; Vortman, Y.; Parchman, T. L.; Albrecht, Tomáš; Petrželková, Adéla; Özkan, L.; Pap, P. L.; Hubbard, J. K.; Hund, A. K.; Safran, R. J.

    2016-01-01

    Roč. 29, č. 12 (2016), s. 2410-2421 ISSN 1010-061X R&D Projects: GA MŠk(CZ) LH14045 Institutional support: RVO:68081766 Keywords : birds * natural selection * population genetics * sexual selection & conflicts * speciation Subject RIV: EG - Zoology Impact factor: 2.792, year: 2016

  12. Antagonistic natural and sexual selection on wing shape in a scrambling damselfly.

    Science.gov (United States)

    Outomuro, David; Söderquist, Linus; Nilsson-Örtman, Viktor; Cortázar-Chinarro, María; Lundgren, Cecilia; Johansson, Frank

    2016-07-01

    Wings are a key trait underlying the evolutionary success of birds, bats, and insects. For over a century, researchers have studied the form and function of wings to understand the determinants of flight performance. However, to understand the evolution of flight, we must comprehend not only how morphology affects performance, but also how morphology and performance affect fitness. Natural and sexual selection can either reinforce or oppose each other, but their role in flight evolution remains poorly understood. Here, we show that wing shape is under antagonistic selection with regard to sexual and natural selection in a scrambling damselfly. In a field setting, natural selection (survival) favored individuals with long and slender forewings and short and broad hindwings. In contrast, sexual selection (mating success) favored individuals with short and broad forewings and narrow-based hindwings. Both types of selection favored individuals of intermediate size. These results suggest that individuals face a trade-off between flight energetics and maneuverability and demonstrate how natural and sexual selection can operate in similar directions for some wing traits, that is, wing size, but antagonistically for others, that is, wing shape. Furthermore, they highlight the need to study flight evolution within the context of species' mating systems and mating behaviors. © 2016 The Author(s).

  13. Computational Approach for Epitaxial Polymorph Stabilization through Substrate Selection

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Hong; Dwaraknath, Shyam S.; Garten, Lauren; Ndione, Paul; Ginley, David; Persson, Kristin A.

    2016-05-25

    With the ultimate goal of finding new polymorphs through targeted synthesis conditions and techniques, we outline a computational framework to select optimal substrates for epitaxial growth using first principle calculations of formation energies, elastic strain energy, and topological information. To demonstrate the approach, we study the stabilization of metastable VO2 compounds which provides a rich chemical and structural polymorph space. We find that common polymorph statistics, lattice matching, and energy above hull considerations recommends homostructural growth on TiO2 substrates, where the VO2 brookite phase would be preferentially grown on the a-c TiO2 brookite plane while the columbite and anatase structures favor the a-b plane on the respective TiO2 phases. Overall, we find that a model which incorporates a geometric unit cell area matching between the substrate and the target film as well as the resulting strain energy density of the film provide qualitative agreement with experimental observations for the heterostructural growth of known VO2 polymorphs: rutile, A and B phases. The minimal interfacial geometry matching and estimated strain energy criteria provide several suggestions for substrates and substrate-film orientations for the heterostructural growth of the hitherto hypothetical anatase, brookite, and columbite polymorphs. These criteria serve as a preliminary guidance for the experimental efforts stabilizing new materials and/or polymorphs through epitaxy. The current screening algorithm is being integrated within the Materials Project online framework and data and hence publicly available.

  14. Sexual selection on receptor organ traits: younger females attract males with longer antennae

    Science.gov (United States)

    Johnson, Tamara L.; Symonds, Matthew R. E.; Elgar, Mark A.

    2017-06-01

    Sexual selection theory predicts that female choice may favour the evolution of elaborate male signals. Darwin also suggested that sexual selection can favour elaborate receiver structures in order to better detect sexual signals, an idea that has been largely ignored. We evaluated this unorthodox perspective by documenting the antennal lengths of male Uraba lugens Walker (Lepidoptera: Nolidae) moths that were attracted to experimentally manipulated emissions of female sex pheromone. Either one or two females were placed in field traps for the duration of their adult lives in order to create differences in the quantity of pheromone emissions from the traps. The mean antennal length of males attracted to field traps baited with a single female was longer than that of males attracted to traps baited with two females, a pattern consistent with Darwin's prediction assuming the latter emits higher pheromone concentrations. Furthermore, younger females attracted males with longer antennae, which may reflect age-specific changes in pheromone emission. These field experiments provide the first direct evidence of an unappreciated role for sexual selection in the evolution of sexual dimorphism in moth antennae and raise the intriguing possibility that females select males with longer antennae through strategic emission of pheromones.

  15. Evolution of male and female genitalia following release from sexual selection.

    Science.gov (United States)

    Cayetano, Luis; Maklakov, Alexei A; Brooks, Robert C; Bonduriansky, Russell

    2011-08-01

    Despite the key functions of the genitalia in sexual interactions and fertilization, the role of sexual selection and conflict in shaping genital traits remains poorly understood. Seed beetle (Callosobruchus maculatus) males possess spines on the intromittent organ, and females possess a thickened reproductive tract wall that also bears spines. We investigated the role of sexual selection and conflict by imposing monogamous mating on eight replicate populations of this naturally polygamous insect, while maintaining eight other populations under polygamy. To establish whether responses to mating system manipulation were robust to ecological context, we simultaneously manipulated life-history selection (early/late reproduction). Over 18-21 generations, male genital spines evolved relatively reduced length in large males (i.e., shallower static allometry) in monogamous populations. Two nonintromittent male genital appendages also evolved in response to the interaction of mating system and ecology. In contrast, no detectable evolution occurred in female genitalia, consistent with the expectation of a delayed response in defensive traits. Our results support a sexually antagonistic role for the male genital spines, and demonstrate the evolution of static allometry in response to variation in sexual selection opportunity. We argue that further advances in the study of genital coevolution will require a much more detailed understanding of the functions of male and female genital traits. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  16. Methodology proposal for matrices selection for hazardous wastes stabilization

    International Nuclear Information System (INIS)

    Silva, Eliane Magalhaes Pereira da; Vasconcelos, Vanderley de; Jordao, Elizabete

    2002-01-01

    The issues of environmental pollution by solid waste arised with the onset of the industrial era. Coping with these issues has been even worsen due to the lack of consciousness and planning for a sound waste management. In addition, most of the companies have found it difficult to keep themselves competitive in a global economy due to the lack of information and by not having access to waste management new technologies. On the other hand, solidification/stabilization technologies are usual practices in the nuclear industry. The aim of this paper is to present a proposal to the development of a methodology, for selection of immobilization binders for hazardous waste, based on the available technologies in the nuclear industry. (author)

  17. Evolution of sexual dimorphism and Rensch’s rule in the beetle genus Limnebius (Hydraenidae: is sexual selection opportunistic?

    Directory of Open Access Journals (Sweden)

    Andrey Rudoy

    2017-03-01

    Full Text Available Sexual size dimorphism (SSD is widespread among animals, with larger females usually attributed to an optimization of resources in reproduction and larger males to sexual selection. A general pattern in the evolution of SSD is Rensch’s rule, which states that SSD increases with body size in species with larger males but decreases when females are larger. We studied the evolution of SSD in the genus Limnebius (Coleoptera, Hydraenidae, measuring SSD and male genital size and complexity of ca. 80% of its 150 species and reconstructing its evolution in a molecular phylogeny with 71 species. We found strong support for a higher evolutionary lability of male body size, which had an overall positive allometry with respect to females and higher evolutionary rates measured over the individual branches of the phylogeny. Increases in SSD were associated to increases in body size, but there were some exceptions with an increase associated to changes in only one sex. Secondary sexual characters (SSC in the external morphology of males appeared several times independently, generally on species that had already increased their size. There was an overall significant correlation between SSD, male body size and male genital size and complexity, although some lineages with complex genitalia had low SSD, and some small species with complex genitalia had no SSD. Our results suggest that the origin of the higher evolutionary variance of male body size may be due to lack of constraints rather than to sexual selection, that may start to act in species with already larger males due to random variation.

  18. Postcopulatory sexual selection is associated with reduced variation in sperm morphology.

    Directory of Open Access Journals (Sweden)

    Sara Calhim

    2007-05-01

    Full Text Available The evolutionary role of postcopulatory sexual selection in shaping male reproductive traits, including sperm morphology, is well documented in several taxa. However, previous studies have focused almost exclusively on the influence of sperm competition on variation among species. In this study we tested the hypothesis that intraspecific variation in sperm morphology is driven by the level of postcopulatory sexual selection in passerine birds.Using two proxy measures of sperm competition level, (i relative testes size and (ii extrapair paternity level, we found strong evidence that intermale variation in sperm morphology is negatively associated with the degree of postcopulatory sexual selection, independently of phylogeny.Our results show that the role of postcopulatory sexual selection in the evolution of sperm morphology extends to an intraspecific level, reducing the variation towards what might be a species-specific 'optimum' sperm phenotype. This finding suggests that while postcopulatory selection is generally directional (e.g., favouring longer sperm across avian species, it also acts as a stabilising evolutionary force within species under intense selection, resulting in reduced variation in sperm morphology traits. We discuss some potential evolutionary mechanisms for this pattern.

  19. Sexual selection, genetic conflict, selfish genes, and the atypical patterns of gene expression in spermatogenic cells.

    Science.gov (United States)

    Kleene, Kenneth C

    2005-01-01

    This review proposes that the peculiar patterns of gene expression in spermatogenic cells are the consequence of powerful evolutionary forces known as sexual selection. Sexual selection is generally characterized by intense competition of males for females, an enormous variety of the strategies to maximize male reproductive success, exaggerated male traits at all levels of biological organization, co-evolution of sexual traits in males and females, and conflict between the sexual advantage of the male trait and the reproductive fitness of females and the individual fitness of both sexes. In addition, spermatogenesis is afflicted by selfish genes that promote their transmission to progeny while causing deleterious effects. Sexual selection, selfish genes, and genetic conflict provide compelling explanations for many atypical features of gene expression in spermatogenic cells including the gross overexpression of certain mRNAs, transcripts encoding truncated proteins that cannot carry out basic functions of the proteins encoded by the same genes in somatic cells, the large number of gene families containing paralogous genes encoding spermatogenic cell-specific isoforms, the large number of testis-cancer-associated genes that are expressed only in spermatogenic cells and malignant cells, and the overbearing role of Sertoli cells in regulating the number and quality of spermatozoa.

  20. Promiscuity, sexual selection, and genetic diversity: a reply to Spurgin.

    Science.gov (United States)

    Lifjeld, Jan T; Gohli, Jostein; Johnsen, Arild

    2013-10-01

    We recently reported a positive association between female promiscuity and genetic diversity across passerine birds, and launched the hypothesis that female promiscuity acts as a balancing selection, pressure maintaining genetic diversity in populations (Gohli et al.2013). Spurgin (2013) questions both our analyses and interpretations. While we agree that the hypothesis needs more comprehensive empirical testing, we find his specific points of criticism unjustified. In a more general perspective, we call for a more explicit recognition of female mating preferences as mechanisms of selection in population genetics theory. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  1. Base Stabilization Guidance and Additive Selection for Pavement Design and Rehabilitation

    Science.gov (United States)

    2017-12-01

    Significant improvements have been made in base stabilization practice that include design specifications and methodology, experience with the selection of stabilizing additives, and equipment for distribution and uniform blending of additives. For t...

  2. Bateman gradients in hermaphrodites: An extended approach to quantify sexual selection.

    NARCIS (Netherlands)

    Anthes, N.; David, P.; Auld, J.R.; Hoffer, J.N.A.; Jarne, P.; Koene, J.M.; Kokko, H.; Lorenzi, M.C.; Pélissié, B.; Sprenger, D.; Staikou, A.; Schärer, L.

    2011-01-01

    Sexual selection is often quantified using Bateman gradients, which represent sex-specific regression slopes of reproductive success on mating success and thus describe the expected fitness returns from mating more often. Although the analytical framework for Bateman gradients aimed at covering all

  3. Sexual selection on land snail shell ornamentation: a hypothesis that may explain shell diversity

    NARCIS (Netherlands)

    Schilthuizen, M.

    2003-01-01

    Background: Many groups of land snails show great interspecific diversity in shell ornamentation, which may include spines on the shell and flanges on the aperture. Such structures have been explained as camouflage or defence, but the possibility that they might be under sexual selection has not

  4. Sexual selection on multivariate phenotypes in Anastrepha Fraterculus (Diptera: Tephritidae) from Argentina

    International Nuclear Information System (INIS)

    Sciurano, R.; Rodriguero, M.; Gomez Cendra, P.; Vilardi, J.; Segura, D.; Cladera, J.L.; Allinghi, Armando

    2007-01-01

    Despite the interest in applying environmentally friendly control methods such as sterile insect technique (SIT) against Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae), information about its biology, taxonomy, and behavior is still insufficient. To increase this information, the present study aims to evaluate the performance of wild flies under field cage conditions through the study of sexual competitiveness among males (sexual selection). A wild population from Horco Molle, Tucuman, Argentina was sampled. Mature virgin males and females were released into outdoor field cages to compete for mating. Morphometric analyses were applied to determine the relationship between the multivariate phenotype and copulatory success. Successful and unsuccessful males were measured for 8 traits: head width (HW), face width (FW), eye length (EL), thorax length (THL), wing length (WL), wing width (WW), femur length (FL), and tibia length (TIL). Combinations of different multivariate statistical methods and graphical analyses were used to evaluate sexual selection on male phenotype. The results indicated that wing width and thorax length would be the most probable targets of sexual selection. They describe a non-linear association between expected fitness and each of these 2 traits. This non-linear relation suggests that observed selection could maintain the diversity related to body size. (author) [es

  5. Sexual selection by male choice in monogamous and polygynous human populations.

    Science.gov (United States)

    Ihara, Y; Aoki, K

    1999-02-01

    The theoretical possibility of coevolution of a viability-reducing female physical trait and a male mating preference for that trait by Fisherian sexual selection in monogamous and polygynous populations is demonstrated using two-locus haploid models. It is assumed that there is dichotomous variation in male resources, resource-rich males have a wider choice among females than resource-poor males, and a female has greater reproductive success when mated with a resource-rich male than a resource-poor one. Under these assumptions, we find that sexual selection operates effectively when female reproductive success is strongly dependent on male resource, the proportion of females that mate with resource-rich males is neither small nor large, the degree of polygyny is low, and resources are inherited from father to son. We suggest that some human female physical traits may have evolved by sexual selection through male choice. The evolution of skin color by sexual selection is discussed as an example. Copyright 1999 Academic Press.

  6. Polygyny and extra-pair paternity enhance the opportunity for sexual selection in blue tits

    NARCIS (Netherlands)

    Vedder, Oscar; Komdeur, Jan; van der Velde, Marco; Schut, Elske; Magrath, Michael J. L.

    Polygyny and extra-pair paternity are generally thought to enhance sexual selection. However, the extent to which these phenomena increase variance in male reproductive success will depend on the covariance between success at these two strategies. We analysed these patterns over four breeding

  7. How sexual selection can drive the evolution of costly sperm ornamentation

    Science.gov (United States)

    Lüpold, Stefan; Manier, Mollie K.; Puniamoorthy, Nalini; Schoff, Christopher; Starmer, William T.; Luepold, Shannon H. Buckley; Belote, John M.; Pitnick, Scott

    2016-05-01

    Post-copulatory sexual selection (PSS), fuelled by female promiscuity, is credited with the rapid evolution of sperm quality traits across diverse taxa. Yet, our understanding of the adaptive significance of sperm ornaments and the cryptic female preferences driving their evolution is extremely limited. Here we review the evolutionary allometry of exaggerated sexual traits (for example, antlers, horns, tail feathers, mandibles and dewlaps), show that the giant sperm of some Drosophila species are possibly the most extreme ornaments in all of nature and demonstrate how their existence challenges theories explaining the intensity of sexual selection, mating-system evolution and the fundamental nature of sex differences. We also combine quantitative genetic analyses of interacting sex-specific traits in D. melanogaster with comparative analyses of the condition dependence of male and female reproductive potential across species with varying ornament size to reveal complex dynamics that may underlie sperm-length evolution. Our results suggest that producing few gigantic sperm evolved by (1) Fisherian runaway selection mediated by genetic correlations between sperm length, the female preference for long sperm and female mating frequency, and (2) longer sperm increasing the indirect benefits to females. Our results also suggest that the developmental integration of sperm quality and quantity renders post-copulatory sexual selection on ejaculates unlikely to treat male-male competition and female choice as discrete processes.

  8. Geography, assortative mating, and the effects of sexual selection on speciation with gene flow.

    Science.gov (United States)

    Servedio, Maria R

    2016-01-01

    Theoretical and empirical research on the evolution of reproductive isolation have both indicated that the effects of sexual selection on speciation with gene flow are quite complex. As part of this special issue on the contributions of women to basic and applied evolutionary biology, I discuss my work on this question in the context of a broader assessment of the patterns of sexual selection that lead to, versus inhibit, the speciation process, as derived from theoretical research. In particular, I focus on how two factors, the geographic context of speciation and the mechanism leading to assortative mating, interact to alter the effect that sexual selection through mate choice has on speciation. I concentrate on two geographic contexts: sympatry and secondary contact between two geographically separated populations that are exchanging migrants and two mechanisms of assortative mating: phenotype matching and separate preferences and traits. I show that both of these factors must be considered for the effects of sexual selection on speciation to be inferred.

  9. On the origin of species by natural and sexual selection

    NARCIS (Netherlands)

    van Doorn, G. Sander; Edelaar, Pim; Weissing, Franz J.

    2009-01-01

    Ecological speciation is considered an adaptive response to selection for local adaptation. However, besides suitable ecological conditions, the process requires assortative mating to protect the nascent species from homogenization by gene flow. By means of a simple model, we demonstrate that

  10. Heat transfer modelling and stability analysis of selective laser melting

    International Nuclear Information System (INIS)

    Gusarov, A.V.; Yadroitsev, I.; Bertrand, Ph.; Smurov, I.

    2007-01-01

    The process of direct manufacturing by selective laser melting basically consists of laser beam scanning over a thin powder layer deposited on a dense substrate. Complete remelting of the powder in the scanned zone and its good adhesion to the substrate ensure obtaining functional parts with improved mechanical properties. Experiments with single-line scanning indicate, that an interval of scanning velocities exists where the remelted tracks are uniform. The tracks become broken if the scanning velocity is outside this interval. This is extremely undesirable and referred to as the 'balling' effect. A numerical model of coupled radiation and heat transfer is proposed to analyse the observed instability. The 'balling' effect at high scanning velocities (above ∼20 cm/s for the present conditions) can be explained by the Plateau-Rayleigh capillary instability of the melt pool. Two factors stabilize the process with decreasing the scanning velocity: reducing the length-to-width ratio of the melt pool and increasing the width of its contact with the substrate

  11. Phenology of Scramble Polygyny in a Wild Population of Chrysolemid Beetles: The Opportunity for and the Strength of Sexual Selection

    Science.gov (United States)

    Baena, Martha Lucía; Macías-Ordóñez, Rogelio

    2012-01-01

    Recent debate has highlighted the importance of estimating both the strength of sexual selection on phenotypic traits, and the opportunity for sexual selection. We describe seasonal fluctuations in mating dynamics of Leptinotarsa undecimlineata (Coleoptera: Chrysomelidae). We compared several estimates of the opportunity for, and the strength of, sexual selection and male precopulatory competition over the reproductive season. First, using a null model, we suggest that the ratio between observed values of the opportunity for sexual selections and their expected value under random mating results in unbiased estimates of the actual nonrandom mating behavior of the population. Second, we found that estimates for the whole reproductive season often misrepresent the actual value at any given time period. Third, mating differentials on male size and mobility, frequency of male fighting and three estimates of the opportunity for sexual selection provide contrasting but complementary information. More intense sexual selection associated to male mobility, but not to male size, was observed in periods with high opportunity for sexual selection and high frequency of male fights. Fourth, based on parameters of spatial and temporal aggregation of female receptivity, we describe the mating system of L. undecimlineata as a scramble mating polygyny in which the opportunity for sexual selection varies widely throughout the season, but the strength of sexual selection on male size remains fairly weak, while male mobility inversely covaries with mating success. We suggest that different estimates for the opportunity for, and intensity of, sexual selection should be applied in order to discriminate how different behavioral and demographic factors shape the reproductive dynamic of populations. PMID:22761675

  12. Sexual selection affects the evolution of lifespan and ageing in the decorated cricket Gryllodes sigillatus.

    Science.gov (United States)

    Archer, C R; Zajitschek, F; Sakaluk, S K; Royle, N J; Hunt, J

    2012-10-01

    Recent work suggests that sexual selection can influence the evolution of ageing and lifespan by shaping the optimal timing and relative costliness of reproductive effort in the sexes. We used inbred lines of the decorated cricket, Gryllodes sigillatus, to estimate the genetic (co)variance between age-dependent reproductive effort, lifespan, and ageing within and between the sexes. Sexual selection theory predicts that males should die sooner and age more rapidly than females. However, a reversal of this pattern may be favored if reproductive effort increases with age in males but not in females. We found that male calling effort increased with age, whereas female fecundity decreased, and that males lived longer and aged more slowly than females. These divergent life-history strategies were underpinned by a positive genetic correlation between early-life reproductive effort and ageing rate in both sexes, although this relationship was stronger in females. Despite these sex differences in life-history schedules, age-dependent reproductive effort, lifespan, and ageing exhibited strong positive intersexual genetic correlations. This should, in theory, constrain the independent evolution of these traits in the sexes and may promote intralocus sexual conflict. Our study highlights the importance of sexual selection to the evolution of sex differences in ageing and lifespan in G. sigillatus. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  13. Sexual selection on land snail shell ornamentation: a hypothesis that may explain shell diversity

    Directory of Open Access Journals (Sweden)

    Schilthuizen Menno

    2003-06-01

    Full Text Available Abstract Background Many groups of land snails show great interspecific diversity in shell ornamentation, which may include spines on the shell and flanges on the aperture. Such structures have been explained as camouflage or defence, but the possibility that they might be under sexual selection has not previously been explored. Presentation of the hypothesis The hypothesis that is presented consists of two parts. First, that shell ornamentation is the result of sexual selection. Second, that such sexual selection has caused the divergence in shell shape in different species. Testing the hypothesis The first part of the hypothesis may be tested by searching for sexual dimorphism in shell ornamentation in gonochoristic snails, by searching for increased variance in shell ornamentation relative to other shell traits, and by mate choice experiments using individuals with experimentally enhanced ornamentation. The second part of the hypothesis may be tested by comparing sister groups and correlating shell diversity with degree of polygamy. Implications of the hypothesis If the hypothesis were true, it would provide an explanation for the many cases of allopatric evolutionary radiation in snails, where shell diversity cannot be related to any niche differentiation or environmental differences.

  14. Intraspecific shape variation in horseshoe crabs: the importance of sexual and natural selection for local adaptation

    DEFF Research Database (Denmark)

    Faurby, Søren; Nielsen, Kasper Sauer Kollerup; Bussarawit, Somchai

    2011-01-01

    . Differences in shape variation between sexes were tested with F-tests, which showed lower intrapopulation morphometric variation in males than females. These results indicate a lower degree of local adaptation on body shape in C. rotundicauda and T. gigas than in L. polyphemus and a lower degree of local......A morphometric analysis of the body shape of three species of horseshoe crabs was undertaken in order to infer the importance of natural and sexual selection. It was expected that natural selection would be most intense, leading to highest regional differentiation, in the American species Limulus...... polyphemus, which has the largest climatic differences between different populations. Local adaptation driven by sexual selection was expected in males but not females because horseshoe crab mating behaviour leads to competition between males, but not between females. Three hundred fifty-nine horseshoe crabs...

  15. Sexual selection of human cooperative behaviour: an experimental study in rural Senegal.

    Directory of Open Access Journals (Sweden)

    Arnaud Tognetti

    Full Text Available Human cooperation in large groups and between non-kin individuals remains a Darwinian puzzle. Investigations into whether and how sexual selection is involved in the evolution of cooperation represent a new and important research direction. Here, 69 groups of four men or four women recruited from a rural population in Senegal played a sequential public-good game in the presence of out-group observers, either of the same sex or of the opposite sex. At the end of the game, participants could donate part of their gain to the village school in the presence of the same observers. Both contributions to the public good and donations to the school, which reflect different components of cooperativeness, were influenced by the sex of the observers. The results suggest that in this non-Western population, sexual selection acts mainly on men's cooperative behaviour with non-kin, whereas women's cooperativeness is mainly influenced by nonsexual social selection.

  16. Is there a role for amplifiers in sexual selection?

    Science.gov (United States)

    Gualla, Filippo; Cermelli, Paolo; Castellano, Sergio

    2008-05-21

    The amplifier hypothesis states that selection could favour the evolution of traits in signallers that improve the ability of receivers to extract honest information from other signals or cues. We provide a formal definition of amplifiers based on the receiver's mechanisms of signal perception and we present a game-theoretical model in which males advertise their quality and females use sequential-sampling tactics to choose among prospective mates. The main effect of an amplifier on the female mating strategy is to increase her mating threshold, making the female more selective as the effectiveness of the amplifier increases. The effects of the amplifier on male advertising strategy depends both on the context and on the types of the amplifier involved. We consider two different contexts for the evolution of amplifiers (when the effect of amplifiers is on signals and when it is on cues) and two types of amplifiers (the 'neutral amplifier', when it improves quality assessment without altering male attractiveness, and the 'attractive amplifier', when it improves both quality assessment and male attractiveness). The game-theoretical model provides two main results. First, neutral and attractive amplifiers represent, respectively, a conditional and an unconditional signalling strategy. In fact, at the equilibrium, neutral amplifiers are displayed only by males whose advertising level lays above the female acceptance threshold, whereas attractive amplifiers are displayed by all signalling males, independent of their quality. Second, amplifiers of signals increase the differences in advertising levels between amplifying and not-amplifying males, but they decrease the differences within each group, so that the system converges towards an 'all-or-nothing' signalling strategy. By applying concepts from information theory, we show that the increase in information transfer at the perception level due to the amplifier of signals is contrasted by a decrease in information

  17. Diploidy and the selective advantage for sexual reproduction in unicellular organisms.

    Science.gov (United States)

    Kleiman, Maya; Tannenbaum, Emmanuel

    2009-11-01

    This article develops mathematical models describing the evolutionary dynamics of both asexually and sexually reproducing populations of diploid unicellular organisms. The asexual and sexual life cycles are based on the asexual and sexual life cycles in Saccharomyces cerevisiae, Baker's yeast, which normally reproduces by asexual budding, but switches to sexual reproduction when stressed. The mathematical models consider three reproduction pathways: (1) Asexual reproduction, (2) self-fertilization, and (3) sexual reproduction. We also consider two forms of genome organization. In the first case, we assume that the genome consists of two multi-gene chromosomes, whereas in the second case, we consider the opposite extreme and assume that each gene defines a separate chromosome, which we call the multi-chromosome genome. These two cases are considered to explore the role that recombination has on the mutation-selection balance and the selective advantage of the various reproduction strategies. We assume that the purpose of diploidy is to provide redundancy, so that damage to a gene may be repaired using the other, presumably undamaged copy (a process known as homologous recombination repair). As a result, we assume that the fitness of the organism only depends on the number of homologous gene pairs that contain at least one functional copy of a given gene. If the organism has at least one functional copy of every gene in the genome, we assume a fitness of 1. In general, if the organism has l homologous pairs that lack a functional copy of the given gene, then the fitness of the organism is kappa(l). The kappa(l) are assumed to be monotonically decreasing, so that kappa(0) = 1 > kappa(1) > kappa(2) > cdots, three dots, centered > kappa(infinity) = 0. For nearly all of the reproduction strategies we consider, we find, in the limit of large N, that the mean fitness at mutation-selection balance is max{2e(-mu) - 1,0} where N is the number of genes in the haploid set of

  18. Sexual and natural selection in the evolution of extended phenotypes: the use of green nesting material in starlings.

    Science.gov (United States)

    Rubalcaba, J G; Polo, V; Maia, R; Rubenstein, D R; Veiga, J P

    2016-08-01

    Although sexual selection is typically considered the predominant force driving the evolution of ritualized sexual behaviours, natural selection may also play an important and often underappreciated role. The use of green aromatic plants among nesting birds has been interpreted as a component of extended phenotype that evolved either via natural selection due to potential sanitary functions or via sexual selection as a signal of male attractiveness. Here, we compared both hypotheses using comparative methods in starlings, a group where this behaviour is widespread. We found that the use of green plants was positively related to male-biased size dimorphism and that it was most likely to occur among cavity-nesting species. These results suggest that this behaviour is likely favoured by sexual selection, but also related to its sanitary use in response to higher parasite loads in cavities. We speculate that the use of green plants in starlings may be facilitated by cavity nesting and was subsequently co-opted as a sexual signal by males. Our results represent an example of how an extended phenotypic component of males becomes sexually selected by females. Thus, both natural selection and sexual selection are necessary to fully understand the evolution of ritualized behaviours involved in courtship. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  19. Environmental change disrupts communication and sexual selection in a stickleback population.

    Science.gov (United States)

    Candolin, Ulrika; Tukiainen, Iina; Bertell, Elina

    2016-04-01

    Environmental change that disrupts communication during mate choice and alters sexual selection could influence population dynamics. Yet little is known about such long-term effects. We investigated experimentally the consequences that disrupted visual communication during mate choice has for the quantity and viability of offspring produced in a threespine stickleback population (Gasterosteus aculeatus). We further related the results to long-term monitoring of population dynamics in the field to determine if changes are apparent under natural conditions. The results show that impaired visual communication because of algal blooms reduces reliability of male visual signals as indicators of offspring survival during their first weeks of life. This relaxes sexual selection but has no effect on the number of offspring hatching, as most males have a high hatching success in turbid water. Despite eutrophication and high turbidity levels that interfere with communication during mate choice, the population has grown during recent decades. Large numbers of offspring hatching, combined with high variation in juvenile fitness, has probably shifted selection to later life history stages and maintained a viable population. Together with reduced cost of sexual selection and ongoing ecosystem changes caused by human activities, this could have promoted population growth. These results point to the complexity of ecosystems and the necessity to consider all influencing factors when attempting to understand impacts of human activities on populations.

  20. Endocrine disruption of sexual selection by an estrogenic herbicide in the mealworm beetle (Tenebrio molitor).

    Science.gov (United States)

    McCallum, Malcolm L; Matlock, Makensey; Treas, Justin; Safi, Barroq; Sanson, Wendy; McCallum, Jamie L

    2013-12-01

    The role that endocrine disruption could play in sexual selection remains relatively untested, and although estrogens occur in insects, little information exists about their biological role in insect reproduction. Atrazine is a commonly applied herbicide that mimics estrogen in vertebrates. Tenebrio molitor were raised from egg to adult under a gradation of environmentally relevant atrazine exposures and a non-treated control. Atrazine was delivered in the drinking water ad libitum. Female T. molitor were provided with a choice between unrelated males raised under three levels of atrazine exposures. Female preference for males demonstrated a non-monotonic inverted U-shaped response to atrazine exposure. There was no significant difference between the control and the high exposure to atrazine. Excluding the control, female preference increased as exposure concentration increased. These results have important repercussions for nonlethal effects of endocrine disruption on populations, their capacity to interfere with sexual selection, and the role of estrogen in pheromone communication among insects.

  1. An Expression of Periodic Phenomena of Fashion on Sexual Selection Model with Conformity Genes and Memes

    Science.gov (United States)

    Mutoh, Atsuko; Tokuhara, Shinya; Kanoh, Masayoshi; Oboshi, Tamon; Kato, Shohei; Itoh, Hidenori

    It is generally thought that living things have trends in their preferences. The mechanism of occurrence of another trends in successive periods is concerned in their conformity. According to social impact theory, the minority is always exists in the group. There is a possibility that the minority make the transition to the majority by conforming agents. Because of agent's promotion of their conform actions, the majority can make the transition. We proposed an evolutionary model with both genes and memes, and elucidated the interaction between genes and memes on sexual selection. In this paper, we propose an agent model for sexual selection imported the concept of conformity. Using this model we try an environment where male agents and female agents are existed, we find that periodic phenomena of fashion are expressed. And we report the influence of conformity and differentiation on the transition of their preferences.

  2. A mechanism of extreme growth and reliable signaling in sexually selected ornaments and weapons.

    Science.gov (United States)

    Emlen, Douglas J; Warren, Ian A; Johns, Annika; Dworkin, Ian; Lavine, Laura Corley

    2012-08-17

    Many male animals wield ornaments or weapons of exaggerated proportions. We propose that increased cellular sensitivity to signaling through the insulin/insulin-like growth factor (IGF) pathway may be responsible for the extreme growth of these structures. We document how rhinoceros beetle horns, a sexually selected weapon, are more sensitive to nutrition and more responsive to perturbation of the insulin/IGF pathway than other body structures. We then illustrate how enhanced sensitivity to insulin/IGF signaling in a growing ornament or weapon would cause heightened condition sensitivity and increased variability in expression among individuals--critical properties of reliable signals of male quality. The possibility that reliable signaling arises as a by-product of the growth mechanism may explain why trait exaggeration has evolved so many different times in the context of sexual selection.

  3. Sexual selection and sex differences in the prevalence of childhood externalizing and adolescent internalizing disorders.

    Science.gov (United States)

    Martel, Michelle M

    2013-11-01

    Despite the well-established sex difference in prevalence of many childhood and adolescent psychopathological conditions, no integrative metatheory of sex differences in psychopathology exists. This review attempts to provide a metatheoretical framework to guide empirical examination of sex differences in prevalence of childhood-onset "externalizing" and adolescent-onset "internalizing" disorders, based on sexual selection evolutionary theory. Sexual selection theory suggests important between-sex differences in markers, mechanisms, etiology, and developmental timing of risk and resilience relevant to psychopathology. Namely, sexual selection theory hypothesizes that disinhibition and sensation-seeking may be important proximate risk markers for childhood-onset externalizing disorders in males. The theory suggests that these male-biased markers may be a product of their higher exposure to prenatal testosterone, which makes them more susceptible to prenatal stressors with downstream effects on dopaminergic neurotransmission, especially for those with genetic alleles associated with lower dopaminergic function. In contrast, sexual selection theory hypothesizes that negative emotionality, empathy, and cognitive rumination may be important proximate risk markers for adolescent-onset internalizing disorders in females. The theory suggests that these markers are propagated by rapidly rising levels of estradiol at puberty that interact with cortisol and oxytocin. These hormones exert downstream effects on the serotonergic system in such a way as to increase females' sensitivity to interpersonal stressors particularly at puberty and especially for those with lower functional serotonergic activity. Such a metatheory can help integrate prior ideas about sex differences and can also generate new predictions of sex differences in markers, etiology, mechanisms, and developmental timing of common forms of psychopathology. © 2013 American Psychological Association

  4. Female responses to experimental removal of sexual selection components in Drosophila melanogaster

    OpenAIRE

    Innocenti, Paolo; Flis, Ilona; Morrow, Edward H.

    2014-01-01

    Background Despite the common assumption that multiple mating should in general be favored in males, but not in females, to date there is no consensus on the general impact of multiple mating on female fitness. Notably, very little is known about the genetic and physiological features underlying the female response to sexual selection pressures. By combining an experimental evolution approach with genomic techniques, we investigated the effects of single and multiple matings on female fecundi...

  5. The expression of pre- and postcopulatory sexually selected traits reflects levels of dietary stress in guppies.

    Directory of Open Access Journals (Sweden)

    Md Moshiur Rahman

    Full Text Available Environmental and ecological conditions can shape the evolution of life history traits in many animals. Among such factors, food or nutrition availability can play an important evolutionary role in moderating an animal's life history traits, particularly sexually selected traits. Here, we test whether diet quantity and/or composition in the form of omega-3 long chain polyunsaturated fatty acids (here termed 'n3LC' influence the expression of pre- and postcopulatory traits in the guppy (Poecilia reticulata, a livebearing poeciliid fish. We assigned males haphazardly to one of two experimental diets supplemented with n3LC, and each of these diet treatments was further divided into two diet 'quantity' treatments. Our experimental design therefore explored the main and interacting effects of two factors (n3LC content and diet quantity on the expression of precopulatory (sexual behaviour and sexual ornamentation, including the size, number and spectral properties of colour spots and postcopulatory (the velocity, viability, number and length of sperm sexually selected traits. Our study revealed that diet quantity had significant effects on most of the pre- and postcopulatory traits, while n3LC manipulation had a significant effect on sperm traits and in particular on sperm viability. Our analyses also revealed interacting effects of diet quantity and n3LC levels on courtship displays, and the area of orange and iridescent colour spots in the males' colour patterns. We also confirmed that our dietary manipulations of n3LC resulted in the differential uptake of n3LC in body and testes tissues in the different n3LC groups. This study reveals the effects of diet quantity and n3LC on behavioural, ornamental and ejaculate traits in P. reticulata and underscores the likely role that diet plays in maintaining the high variability in these condition-dependent sexual traits.

  6. The evolution of autistic-like and schizotypal traits: A sexual selection hypothesis

    Directory of Open Access Journals (Sweden)

    Marco Del Giudice

    2010-08-01

    Full Text Available In this paper we present a new hypothesis on the evolution of autistic-like and schizotypal personality traits. We argue that autistic-like and schizotypal traits contribute in opposite ways to individual differences in reproductive and mating strategies, and have been maintained – at least in part – by sexual selection through mate choice. Whereas positive schizotypy can be seen as a psychological phenotype oriented to high mating effort and good genes displays in both sexes, autistic-like traits in their non-pathological form contribute to a male-typical strategy geared toward high parental investment, low mating effort, and long-term resource allocation. At the evolutionary-genetic level, this sexual selection hypothesis is consistent with Crespi and Badcock’s “imprinted brain” theory of autism and psychosis; the effect of offspring mating behavior on resource flow within the family connects sexual selection with genomic imprinting in the context of human biparental care. We conclude by presenting the results of an empirical study testing one of the predictions derived from our hypothesis. In a sample of 200 college students, autistic-like traits predicted lower interest in short-term mating, higher partner-specific investment, and stronger commitment to long-term romantic relations, whereas positive schizotypy showed the opposite pattern of effects.

  7. Sex differences in parental care: Gametic investment, sexual selection, and social environment.

    Science.gov (United States)

    Liker, András; Freckleton, Robert P; Remeš, Vladimir; Székely, Tamás

    2015-11-01

    Male and female parents often provide different type and amount of care to their offspring. Three major drivers have been proposed to explain parental sex roles: (1) differential gametic investment by males and females that precipitates into sex difference in care, (2) different intensity of sexual selection acting on males and females, and (3) biased social environment that facilitates the more common sex to provide more care. Here, we provide the most comprehensive assessment of these hypotheses using detailed parental care data from 792 bird species covering 126 families. We found no evidence for the gametic investment hypothesis: neither gamete sizes nor gamete production by males relative to females was related to sex difference in parental care. However, sexual selection correlated with parental sex roles, because the male share in care relative to female decreased with both extra-pair paternity and frequency of male polygamy. Parental sex roles were also related to social environment, because male parental care increased with male-biased adult sex ratios (ASRs). Taken together, our results are consistent with recent theories suggesting that gametic investment is not tied to parental sex roles, and highlight the importance of both sexual selection and ASR in influencing parental sex roles. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

  8. Statistical aspects of evolution under natural selection, with implications for the advantage of sexual reproduction.

    Science.gov (United States)

    Crouch, Daniel J M

    2017-10-27

    The prevalence of sexual reproduction remains mysterious, as it poses clear evolutionary drawbacks compared to reproducing asexually. Several possible explanations exist, with one of the most likely being that finite population size causes linkage disequilibria to randomly generate and impede the progress of natural selection, and that these are eroded by recombination via sexual reproduction. Previous investigations have either analysed this phenomenon in detail for small numbers of loci, or performed population simulations for many loci. Here we present a quantitative genetic model for fitness, based on the Price Equation, in order to examine the theoretical consequences of randomly generated linkage disequilibria when there are many loci. In addition, most previous work has been concerned with the long-term consequences of deleterious linkage disequilibria for population fitness. The expected change in mean fitness between consecutive generations, a measure of short-term evolutionary success, is shown under random environmental influences to be related to the autocovariance in mean fitness between the generations, capturing the effects of stochastic forces such as genetic drift. Interaction between genetic drift and natural selection, due to randomly generated linkage disequilibria, is demonstrated to be one possible source of mean fitness autocovariance. This suggests a possible role for sexual reproduction in reducing the negative effects of genetic drift, thereby improving the short-term efficacy of natural selection. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Developmental success, stability, and plasticity in closely related parthenogenetic and sexual lizards (Heteronotia, Gekkonidae).

    Science.gov (United States)

    Kearney, Michael; Shine, Richard

    2004-07-01

    was the case for their sexual relatives. Thus, the evolution of asexual reproduction in this species complex has modified both mean hatchling viability and the norms of reaction linking hatchling phenotypes to incubation temperature. Discussions on the reasons why parthenogenetic organisms are scarce in nature should take into account interactive effects such as these; future work could usefully try to tease apart the roles of parthenogenesis, its hybrid origin (and thus effects on ploidy and heterozygosity, etc.), and clonal selection in generating these divergent embryonic responses.

  10. Condition-dependence, pleiotropy and the handicap principle of sexual selection in melanin-based colouration.

    Science.gov (United States)

    Roulin, Alexandre

    2016-05-01

    The signalling function of melanin-based colouration is debated. Sexual selection theory states that ornaments should be costly to produce, maintain, wear or display to signal quality honestly to potential mates or competitors. An increasing number of studies supports the hypothesis that the degree of melanism covaries with aspects of body condition (e.g. body mass or immunity), which has contributed to change the initial perception that melanin-based colour ornaments entail no costs. Indeed, the expression of many (but not all) melanin-based colour traits is weakly sensitive to the environment but strongly heritable suggesting that these colour traits are relatively cheap to produce and maintain, thus raising the question of how such colour traits could signal quality honestly. Here I review the production, maintenance and wearing/displaying costs that can generate a correlation between melanin-based colouration and body condition, and consider other evolutionary mechanisms that can also lead to covariation between colour and body condition. Because genes controlling melanic traits can affect numerous phenotypic traits, pleiotropy could also explain a linkage between body condition and colouration. Pleiotropy may result in differently coloured individuals signalling different aspects of quality that are maintained by frequency-dependent selection or local adaptation. Colouration may therefore not signal absolute quality to potential mates or competitors (e.g. dark males may not achieve a higher fitness than pale males); otherwise genetic variation would be rapidly depleted by directional selection. As a consequence, selection on heritable melanin-based colouration may not always be directional, but mate choice may be conditional to environmental conditions (i.e. context-dependent sexual selection). Despite the interest of evolutionary biologists in the adaptive value of melanin-based colouration, its actual role in sexual selection is still poorly understood.

  11. Sexual selection and the adaptive evolution of PKDREJ protein in primates and rodents.

    Science.gov (United States)

    Vicens, Alberto; Gómez Montoto, Laura; Couso-Ferrer, Francisco; Sutton, Keith A; Roldan, Eduardo R S

    2015-02-01

    PKDREJ is a testis-specific protein thought to be located on the sperm surface. Functional studies in the mouse revealed that loss of PKDREJ has effects on sperm transport and the ability to undergo an induced acrosome reaction. Thus, PKDREJ has been considered a potential target of post-copulatory sexual selection in the form of sperm competition. Proteins involved in reproductive processes often show accelerated evolution. In many cases, this rapid divergence is promoted by positive selection which may be driven, at least in part, by post-copulatory sexual selection. We analysed the evolution of the PKDREJ protein in primates and rodents and assessed whether PKDREJ divergence is associated with testes mass relative to body mass, which is a reliable proxy of sperm competition levels. Evidence of an association between the evolutionary rate of the PKDREJ gene and testes mass relative to body mass was not found in primates. Among rodents, evidence of positive selection was detected in the Pkdrej gene in the family Cricetidae but not in Muridae. We then assessed whether Pkdrej divergence is associated with episodes of sperm competition in these families. We detected a positive significant correlation between the evolutionary rates of Pkdrej and testes mass relative to body mass in cricetids. These findings constitute the first evidence of post-copulatory sexual selection influencing the evolution of a protein that participates in the mechanisms regulating sperm transport and the acrosome reaction, strongly suggesting that positive selection may act on these fertilization steps, leading to advantages in situations of sperm competition. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Sexonomics: a commentary and review of selected sexually transmitted disease studies in the economics literature.

    Science.gov (United States)

    Chesson, Harrell W

    2012-03-01

    The purpose of this review is to highlight selected studies in the economics literature that address sexually transmitted disease (STD)-related topics that are typically not examined in the STD literature. Two databases (EconLit and Web of Science) were searched to locate STD-related articles in the economics journals. Relevant articles were also identified in other ways, such as informal discussions with colleagues familiar with the literature. To maintain a focus on unique STD-related topics, studies with topics common in the STD literature (e.g., cost-effectiveness, transmission modeling) were excluded. Selected STD-related studies in the economics literature were grouped into the following 8 topics: impact of abortion laws and policies on sexual health outcomes; same-sex marriage and syphilis rates; alcohol policy and STD rates; welfare laws and STD rates; discounting the future; HIV disclosure laws; the impact of tolerance for gays on HIV incidence; and economic versus epidemiologic models of HIV dynamics. A general theme of STD-related studies in the economics literature is that laws and policies that increased the "cost" of risky sex tended to reduce the demand for risky sex, and therefore reduce the incidence of STDs. Economic research can contribute in novel ways to our understanding of influences on risky sexual behavior at the individual level and STD incidence at the population level. Economists and STD experts could mutually benefit from increased collaboration.

  13. Stability of core–shell nanowires in selected model solutions

    International Nuclear Information System (INIS)

    Kalska-Szostko, B.; Wykowska, U.; Basa, A.; Zambrzycka, E.

    2015-01-01

    Highlights: • Stability of the core–shell nanowires in environmental solutions were tested. • The most and the least aggressive solutions were determined. • The influence of different solutions on magnetic nanowires core was found out. - Abstract: This paper presents the studies of stability of magnetic core–shell nanowires prepared by electrochemical deposition from an acidic solution containing iron in the core and modified surface layer. The obtained nanowires were tested according to their durability in distilled water, 0.01 M citric acid, 0.9% NaCl, and commercial white wine (12% alcohol). The proposed solutions were chosen in such a way as to mimic food related environment due to a possible application of nanowires as additives to, for example, packages. After 1, 2 and 3 weeks wetting in the solutions, nanoparticles were tested by Infrared Spectroscopy, Atomic Absorption Spectroscopy, Transmission Electron Microscopy and X-ray diffraction methods

  14. Stability of core–shell nanowires in selected model solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kalska-Szostko, B., E-mail: kalska@uwb.edu.pl; Wykowska, U.; Basa, A.; Zambrzycka, E.

    2015-03-30

    Highlights: • Stability of the core–shell nanowires in environmental solutions were tested. • The most and the least aggressive solutions were determined. • The influence of different solutions on magnetic nanowires core was found out. - Abstract: This paper presents the studies of stability of magnetic core–shell nanowires prepared by electrochemical deposition from an acidic solution containing iron in the core and modified surface layer. The obtained nanowires were tested according to their durability in distilled water, 0.01 M citric acid, 0.9% NaCl, and commercial white wine (12% alcohol). The proposed solutions were chosen in such a way as to mimic food related environment due to a possible application of nanowires as additives to, for example, packages. After 1, 2 and 3 weeks wetting in the solutions, nanoparticles were tested by Infrared Spectroscopy, Atomic Absorption Spectroscopy, Transmission Electron Microscopy and X-ray diffraction methods.

  15. Alleles versus genotypes: Genetic interactions and the dynamics of selection in sexual populations

    Science.gov (United States)

    Neher, Richard

    2010-03-01

    Physical interactions between amino-acids are essential for protein structure and activity, while protein-protein interactions and regulatory interactions are central to cellular function. As a consequence of these interactions, the combined effect of two mutations can differ from the sum of the individual effects of the mutations. This phenomenon of genetic interaction is known as epistasis. However, the importance of epistasis and its effects on evolutionary dynamics are poorly understood, especially in sexual populations where recombination breaks up existing combinations of alleles to produce new ones. Here, we present a computational model of selection dynamics involving many epistatic loci in a recombining population. We demonstrate that a large number of polymorphic interacting loci can, despite frequent recombination, exhibit cooperative behavior that locks alleles into favorable genotypes leading to a population consisting of a set of competing clones. As the recombination rate exceeds a certain critical value this ``genotype selection'' phase disappears in an abrupt transition giving way to ``allele selection'' - the phase where different loci are only weakly correlated as expected in sexually reproducing populations. Clustering of interacting sets of genes on a chromosome leads to the emergence of an intermediate regime, where localized blocks of cooperating alleles lock into genetic modules. Large populations attain highest fitness at a recombination rate just below critical, suggesting that natural selection might tune recombination rates to balance the beneficial aspect of exploration of genotype space with the breaking up of synergistic allele combinations.

  16. A change in competitive context reverses sexual selection on male size.

    Science.gov (United States)

    Kasumovic, M M; Andrade, M C B

    2009-02-01

    In studies of sexual selection, larger size is often argued to increase male fitness, and relatively smaller males are explained by genetic and/or environmental variation. We demonstrate that a size-development life-history trade-off could underlie the maintenance of a broad, unimodal distribution of size in male redback spiders (Latrodectus hasselti). Larger males are superior in direct competition, but redback males mature rapidly at small size in the presence of females. In field enclosures, we simulated two competitive contexts favouring development of divergent male sizes. Relatively smaller males lost when competing directly, but had 10 times higher fitness than relatively larger males when given the temporal advantage of rapid development. Linear selection gradients confirmed the reversal of selection on size, showing that it is critical to consider life-history decisions underlying the development of traits related to fitness.

  17. Sexual selection on male size drives the evolution of male-biased sexual size dimorphism via the prolongation of male development.

    Science.gov (United States)

    Rohner, Patrick T; Blanckenhorn, Wolf U; Puniamoorthy, Nalini

    2016-06-01

    Sexual size dimorphism (SSD) arises when the net effects of natural and sexual selection on body size differ between the sexes. Quantitative SSD variation between taxa is common, but directional intraspecific SSD reversals are rare. We combined micro- and macroevolutionary approaches to study geographic SSD variation in closely related black scavenger flies. Common garden experiments revealed stark intra- and interspecific variation: Sepsis biflexuosa is monomorphic across the Holarctic, while S. cynipsea (only in Europe) consistently exhibits female-biased SSD. Interestingly, S. neocynipsea displays contrasting SSD in Europe (females larger) and North America (males larger), a pattern opposite to the geographic reversal in SSD of S. punctum documented in a previous study. In accordance with the differential equilibrium model for the evolution of SSD, the intensity of sexual selection on male size varied between continents (weaker in Europe), whereas fecundity selection on female body size did not. Subsequent comparative analyses of 49 taxa documented at least six independent origins of male-biased SSD in Sepsidae, which is likely caused by sexual selection on male size and mediated by bimaturism. Therefore, reversals in SSD and the associated changes in larval development might be much more common and rapid and less constrained than currently assumed. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  18. Coevolution of parental investment and sexually selected traits drives sex-role divergence.

    Science.gov (United States)

    Fromhage, Lutz; Jennions, Michael D

    2016-08-18

    Sex-role evolution theory attempts to explain the origin and direction of male-female differences. A fundamental question is why anisogamy, the difference in gamete size that defines the sexes, has repeatedly led to large differences in subsequent parental care. Here we construct models to confirm predictions that individuals benefit less from caring when they face stronger sexual selection and/or lower certainty of parentage. However, we overturn the widely cited claim that a negative feedback between the operational sex ratio and the opportunity cost of care selects for egalitarian sex roles. We further argue that our model does not predict any effect of the adult sex ratio (ASR) that is independent of the source of ASR variation. Finally, to increase realism and unify earlier models, we allow for coevolution between parental investment and investment in sexually selected traits. Our model confirms that small initial differences in parental investment tend to increase due to positive evolutionary feedback, formally supporting long-standing, but unsubstantiated, verbal arguments.

  19. Genome size variation affects song attractiveness in grasshoppers: evidence for sexual selection against large genomes.

    Science.gov (United States)

    Schielzeth, Holger; Streitner, Corinna; Lampe, Ulrike; Franzke, Alexandra; Reinhold, Klaus

    2014-12-01

    Genome size is largely uncorrelated to organismal complexity and adaptive scenarios. Genetic drift as well as intragenomic conflict have been put forward to explain this observation. We here study the impact of genome size on sexual attractiveness in the bow-winged grasshopper Chorthippus biguttulus. Grasshoppers show particularly large variation in genome size due to the high prevalence of supernumerary chromosomes that are considered (mildly) selfish, as evidenced by non-Mendelian inheritance and fitness costs if present in high numbers. We ranked male grasshoppers by song characteristics that are known to affect female preferences in this species and scored genome sizes of attractive and unattractive individuals from the extremes of this distribution. We find that attractive singers have significantly smaller genomes, demonstrating that genome size is reflected in male courtship songs and that females prefer songs of males with small genomes. Such a genome size dependent mate preference effectively selects against selfish genetic elements that tend to increase genome size. The data therefore provide a novel example of how sexual selection can reinforce natural selection and can act as an agent in an intragenomic arms race. Furthermore, our findings indicate an underappreciated route of how choosy females could gain indirect benefits. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  20. Blue Shifting Tuning of the Selective Reflection of Polymer Stabilized Cholesteric Liquid Crystals (Postprint)

    Science.gov (United States)

    2017-08-08

    crystal (MLC-2079, Merck). The polymer stabi- lizing network was formed within the samples by photoinitiated polymerization with 50–700 mW cm2 of 365...AFRL-RX-WP-JA-2017-0347 BLUE-SHIFTING TUNING OF THE SELECTIVE REFLECTION OF POLYMER STABILIZED CHOLESTERIC LIQUID CRYSTALS (POSTPRINT...BLUE-SHIFTING TUNING OF THE SELECTIVE REFLECTION OF POLYMER STABILIZED CHOLESTERIC LIQUID CRYSTALS (POSTPRINT) 5a. CONTRACT NUMBER FA8650-16-F

  1. An introduction to genetic quality in the context of sexual selection.

    Science.gov (United States)

    Pitcher, Trevor E; Mays, Herman L

    2008-09-01

    This special issue of Genetica brings together empirical researchers and theoreticians to present the latest on the evolutionary ecology of genetic quality in the context of sexual selection. The work comes from different fields of study including behavioral ecology, quantitative genetics and molecular genetics on a diversity of organisms using different approaches from comparative studies, mathematical modeling, field studies and laboratory experiments. The papers presented in this special issue primarily focus on genetic quality in relation to (1) sources of genetic variation, (2) polyandry, (3) new theoretical developments and (4) comprehensive reviews.

  2. Sexual Selection of Human Cooperative Behaviour: An Experimental Study in Rural Senegal

    OpenAIRE

    Tognetti, Arnaud; Berticat, Claire; Raymond, Michel; Faurie, Charlotte

    2012-01-01

    Human cooperation in large groups and between non-kin individuals remains a Darwinian puzzle. Investigations into whether and how sexual selection is involved in the evolution of cooperation represent a new and important research direction. Here, 69 groups of four men or four women recruited from a rural population in Senegal played a sequential public-good game in the presence of out-group observers, either of the same sex or of the opposite sex. At the end of the game, participants could do...

  3. Facial attractiveness, sexual selection, and personnel selection : when evolved preferences matter

    NARCIS (Netherlands)

    Luxen, MF; Van de Vijver, FJR

    Using an evolutionary perspective, we looked at sex differences in the influence of facial attractiveness of applicants in hiring decisions, and determined whether expected contact intensity with applicants and experience in personnel selection moderated this influence. We found effects of evolved

  4. The Effects of Housing Status, Stability and the Social Contexts of Housing on Drug and Sexual Risk Behaviors.

    Science.gov (United States)

    Dickson-Gomez, Julia; McAuliffe, Timothy; Quinn, Katherine

    2017-07-01

    Research on the relationship between housing instability and HIV risk has often focused on two different conceptions of stability. In one conceptualization, housing stability is defined according to physical location with homeless or unstably housed individuals defined as those who reside in places not meant for human habitation or in emergency shelters. The other conceptualization has defined housing stability as individuals' degree of transience, often operationalized as the number of moves or evictions a person has had within a specified amount of time. Less studied has been the social context of living situation, e.g. living with other drug users, conflict over living expenses, or having to have sex in order to stay. This paper uses data from 392 low-income residents in Hartford, CT to explore how people in different housing situations-including those who are housed and homeless-experience housing stability, feelings of security in their homes, and the social context of their housing. We then explore how these varied measures of housing context affect drug use frequency and sexual risk. Results show that participants who are homeless feel more overall housing instability in terms of number of moves and negative reasons for moving. Those who were doubled up with family or friends were more likely to experience conflict over household expenses and more likely to live with drug users. Among homeless and housed, hard drug use was associated with experiencing violence in the place where they lived, perceiving greater housing stability, having moved for a positive reason, doubling up, and longer periods of homelessness, while number of moves and longer prison sentence predicted sexual risk. Among the housed, living with other drug users was associated with more hard drug use, while contributing money toward household expenses was associated with less hard drug use. Two significant interactions were associated with sexual risk among the housed. Those with longer

  5. Corridors of barchan dunes: Stability and size selection

    DEFF Research Database (Denmark)

    Hersen, P.; Andersen, Ken Haste; Elbelrhiti, H.

    2004-01-01

    state. Second, the propagation speed of dunes decreases with the size of the dune: this leads, through the collision process, to a coarsening of barchan fields. We show that these phenomena are not specific to the model, but result from general and robust mechanisms. The length scales needed...... for these instabilities to develop are derived and discussed. They turn out to be much smaller than the dune field length. As a conclusion, there should exist further, yet unknown, mechanisms regulating and selecting the size of dunes....

  6. Sexually selected traits: a fundamental framework for studies on behavioral epigenetics.

    Science.gov (United States)

    Jašarević, Eldin; Geary, David C; Rosenfeld, Cheryl S

    2012-01-01

    Emerging evidence suggests that epigenetic-based mechanisms contribute to various aspects of sex differences in brain and behavior. The major obstacle in establishing and fully understanding this linkage is identifying the traits that are most susceptible to epigenetic modification. We have proposed that sexual selection provides a conceptual framework for identifying such traits. These are traits involved in intrasexual competition for mates and intersexual choice of mating partners and generally entail a combination of male-male competition and female choice. These behaviors are programmed during early embryonic and postnatal development, particularly during the transition from the juvenile to adult periods, by exposure of the brain to steroid hormones, including estradiol and testosterone. We evaluate the evidence that endocrine-disrupting compounds, including bisphenol A, can interfere with the vital epigenetic and gene expression pathways and with the elaboration of sexually selected traits with epigenetic mechanisms presumably governing the expression of these traits. Finally, we review the evidence to suggest that these steroid hormones can induce a variety of epigenetic changes in the brain, including the extent of DNA methylation, histone protein alterations, and even alterations of noncoding RNA, and that many of the changes differ between males and females. Although much previous attention has focused on primary sex differences in reproductive behaviors, such as male mounting and female lordosis, we outline why secondary sex differences related to competition and mate choice might also trace their origins back to steroid-induced epigenetic programming in disparate regions of the brain.

  7. Queen Specific Exocrine Glands in Legionary Ants and Their Possible Function in Sexual Selection.

    Science.gov (United States)

    Hölldobler, Bert

    2016-01-01

    The colonies of army ants and some other legionary ant species have single, permanently wingless queens with massive post petioles and large gasters. Such highly modified queens are called dichthadiigynes. This paper presents the unusually rich exocrine gland endowment of dichthadiigynes, which is not found in queens of other ant species. It has been suggested these kinds of glands produce secretions that attract and maintain worker retinues around queens, especially during migration. However, large worker retinues also occur in non-legionary species whose queens do not have such an exuberance of exocrine glands. We argue and present evidence in support of our previously proposed hypothesis that the enormous outfit of exocrine glands found in dichthadiigynes is due to sexual selection mediated by workers as the main selecting agents.

  8. Queen Specific Exocrine Glands in Legionary Ants and Their Possible Function in Sexual Selection.

    Directory of Open Access Journals (Sweden)

    Bert Hölldobler

    Full Text Available The colonies of army ants and some other legionary ant species have single, permanently wingless queens with massive post petioles and large gasters. Such highly modified queens are called dichthadiigynes. This paper presents the unusually rich exocrine gland endowment of dichthadiigynes, which is not found in queens of other ant species. It has been suggested these kinds of glands produce secretions that attract and maintain worker retinues around queens, especially during migration. However, large worker retinues also occur in non-legionary species whose queens do not have such an exuberance of exocrine glands. We argue and present evidence in support of our previously proposed hypothesis that the enormous outfit of exocrine glands found in dichthadiigynes is due to sexual selection mediated by workers as the main selecting agents.

  9. Sex-specific effects of natural and sexual selection on the evolution of life span and ageing in Drosophila simulans

    NARCIS (Netherlands)

    Archer, C.R.; Duffy, E.; Hosken, D.J.; Mokkonen, M.; Okada, K.; Oku, K.; Sharma, M.D.; Hunt, J.

    2015-01-01

    1. Variation in the strength of age-dependent natural selection shapes differences in ageing rates across species and populations. Likewise, sexual selection can promote divergent patterns of senescence across the sexes. However, the effects of these processes on the evolution of ageing have largely

  10. Allometry as evidence of sexual selection in monochromatic birds: the case of the Coscoroba Swan (Anseriformes: Anatidae

    Directory of Open Access Journals (Sweden)

    Cecilia P. Calabuig

    2013-08-01

    Full Text Available The Coscoroba Swan, Coscoroba coscoroba (Molina, 1782, is a poorly known aberrant Anserine endemic to South America. We captured adult birds (189 male, 157 female from the largest population in Brazil at the Taim Ecological Reserve, State of Rio Grande do Sul, Brazil. Different patterns between sexes can reflect differences in selection, and positive allometry may indicate that a character is sexually selected. We used body weight and 10 morphological measurements to examine allometric differences between males and females of C. coscoroba. Males were consistently larger than females. Analysis of scaling relationships against body mass showed that nostril, tail, wing and bill height were positively allometric (i.e., heavier birds had relatively larger character lengths, but there were no sexual differences in allometric slopes. However, for a given mass, mature females had longer tails, longer wings (up to metacarpophalangeal articulation and shorter heads than males. In the light of current debate in the literature, we discuss whether such positively allometric traits and sexual differences in scaling may be indicative of sexual selection. Although Coscoroba Swan is a monogamous species, increasing the size of some attributes may confer some advantage for mate selection or male-male competition and, contrary to other studies, we suggest that positively allometric slopes alone should not be considered as evidence for sexual selection of the considered traits.

  11. The Role of Selection Effects in the Contact Hypothesis: Results from a U.S. National Survey on Sexual Prejudice.

    Science.gov (United States)

    Loehr, Annalise; Doan, Long; Miller, Lisa R

    2015-11-01

    Empirical research has documented that contact with lesbians and gays is associated with more positive feelings toward and greater support for legal rights for them, but we know less about whether these effects extend to informal aspects of same-sex relationships, such as reactions to public displays of affection. Furthermore, many studies have assumed that contact influences levels of sexual prejudice; however, the possibility of selection effects, in which less sexually prejudiced people have contact, and more sexually prejudiced people do not, raises some doubts about this assumption. We used original data from a nationally representative sample of heterosexuals to determine whether those reporting contact with a lesbian, gay, bisexual, or transgender friend or relative exhibited less sexual prejudice toward lesbian and gay couples than those without contact. This study examined the effect of contact on attitudes toward formal rights and a relatively unexplored dimension, informal privileges. We estimated the effect of having contact using traditional (ordinary least squares regression) methods before accounting for selection effects using propensity score matching. After accounting for selection effects, we found no significant differences between the attitudes of those who had contact and those who did not, for either formal or informal measures. Thus, selection effects appeared to play a pivotal role in confounding the link between contact and sexual prejudice, and future studies should exercise caution in interpreting results that do not account for such selection effects.

  12. Effects of potential partners' physical attractiveness and socioeconomic status on sexuality and partner selection.

    Science.gov (United States)

    Townsend, J M; Levy, G D

    1990-04-01

    Male (n = 170) and female (n = 212) college students viewed photographs, which had been prerated for physical attractiveness, of three opposite-sex individuals. These photographs were paired with three levels of occupational status and income. Subjects indicated their willingness to engage in relationships of varying levels of sexual intimacy and marital potential with the portrayed individuals. Analyses of variance, correlations, and trend analyses supported the hypotheses. Compared to men, women are more likely to prefer or insist that sexual intercourse occur in relationships that involve affection and marital potential, and women place more emphasis than men do on partners' SES in such relationships. Consequently, men's SES and their willingness and ability to invest affection and resources in relationships may often outweigh the effects of their physical attractiveness in women's actual selection of partners. These results and the literature reviewed are more consistent with parental investment theory than with the view that these sex differences are solely the result of differential access to resources and differential socialization.

  13. Childhood sexual abuse, selective attention for sexual cues and the effects of testosterone with or without Vardenafil on physiological sexual arousal in women with sexual dysfunction: a pilot study

    NARCIS (Netherlands)

    van der Made, F.; Bloemers, J.; van Ham, D.; El Yassem, W.; Kleiverda, G.; Everaerd, W.; Olivier, B.; Tuiten, A.

    2009-01-01

    INTRODUCTION: Female sexual dysfunction (FSD) may be associated with reduced central sensitivity for sexual cues. A single dose of testosterone might induce an increase in sensitivity for sexual stimuli, which in turn allows a PDE5 inhibitor to be effective in boosting the physiological sexual

  14. SEXUAL SELECTION. Irrationality in mate choice revealed by túngara frogs.

    Science.gov (United States)

    Lea, Amanda M; Ryan, Michael J

    2015-08-28

    Mate choice models derive from traditional microeconomic decision theory and assume that individuals maximize their Darwinian fitness by making economically rational decisions. Rational choices exhibit regularity, whereby the relative strength of preferences between options remains stable when additional options are presented. We tested female frogs with three simulated males who differed in relative call attractiveness and call rate. In binary choice tests, females' preferences favored stimulus caller B over caller A; however, with the addition of an inferior "decoy" C, females reversed their preferences and chose A over B. These results show that the relative valuation of mates is not independent of inferior alternatives in the choice set and therefore cannot be explained with the rational choice models currently used in sexual selection theory. Copyright © 2015, American Association for the Advancement of Science.

  15. Good genes and sexual selection in dung beetles (Onthophagus taurus: genetic variance in egg-to-adult and adult viability.

    Directory of Open Access Journals (Sweden)

    Francisco Garcia-Gonzalez

    2011-01-01

    Full Text Available Whether species exhibit significant heritable variation in fitness is central for sexual selection. According to good genes models there must be genetic variation in males leading to variation in offspring fitness if females are to obtain genetic benefits from exercising mate preferences, or by mating multiply. However, sexual selection based on genetic benefits is controversial, and there is limited unambiguous support for the notion that choosy or polyandrous females can increase the chances of producing offspring with high viability. Here we examine the levels of additive genetic variance in two fitness components in the dung beetle Onthophagus taurus. We found significant sire effects on egg-to-adult viability and on son, but not daughter, survival to sexual maturity, as well as moderate coefficients of additive variance in these traits. Moreover, we do not find evidence for sexual antagonism influencing genetic variation for fitness. Our results are consistent with good genes sexual selection, and suggest that both pre- and postcopulatory mate choice, and male competition could provide indirect benefits to females.

  16. Does students' exposure to gender discrimination and sexual harassment in medical school affect specialty choice and residency program selection?

    Science.gov (United States)

    Stratton, Terry D; McLaughlin, Margaret A; Witte, Florence M; Fosson, Sue E; Nora, Lois Margaret

    2005-04-01

    To examine the role of gender discrimination and sexual harassment in medical students' choice of specialty and residency program. Anonymous, self-administered questionnaires were distributed in 1997 to fourth-year students enrolled in 14 public and private U.S. medical schools. In addition to reporting the frequency of gender discrimination and sexual harassment encountered during preclinical coursework, core clerkships, elective clerkships, and residency selection, students assessed the impact of these exposures (none, a little, some, quite a bit, the deciding factor) on their specialty choices and rankings of residency programs. A total of 1,314 (69%) useable questionnaires were returned. Large percentages of men (83.2%) and women (92.8%) experienced, observed, or heard about at least one incident of gender discrimination and sexual harassment during medical school, although more women reported such behavior across all training contexts. Compared with men, significantly (p harassment influenced their specialty choices (45.3% versus 16.4%) and residency rankings (25.3% versus 10.9%). Across all specialties, more women than men experienced gender discrimination and sexual harassment during residency selection, with one exception: a larger percentage of men choosing obstetrics and gynecology experienced such behavior. Among women, those choosing general surgery were most likely to experience gender discrimination and sexual harassment during residency selection. Interestingly, correlations between exposure to gender discrimination and sexual harassment and self-assessed impact on career decisions tended to be larger for men, suggesting that although fewer men are generally affected, they may weigh such experiences more heavily in their choice of specialty and residency program. This study suggests that exposure to gender discrimination and sexual harassment during undergraduate education may influence some medical students' choice of specialty and, to a lesser

  17. Modeling Sexual Selection in Túngara Frog and Rationality of Mate Choice.

    Science.gov (United States)

    Vargas Bernal, Esteban; Sanabria Malagon, Camilo

    2017-12-01

    The males of the species of frogs Engystomops pustulosus produce simple and complex calls to lure females, as a way of intersexual selection. Complex calls lead males to a greater reproductive success than what simple calls do. However, the complex calls are also more attractive to their main predator, the bat Trachops cirrhosus. Therefore, as M. Ryan suggests in (The túngara frog: a study in sexual selection and communication. University of Chicago Press, Chicago, 1985), the complexity of the calls lets the frogs keep a trade-off between reproductive success and predation. In this paper, we verify this trade-off from the perspective of game theory. We first model the proportion of simple calls as a symmetric game of two strategies. We also model the effect of adding a third strategy, males that keep quiet and intercept females, which would play a role of intrasexual selection. Under the assumption that the decision of the males takes into account this trade-off between reproductive success and predation, our model reproduces the observed behavior reported in the literature with minimal assumption on the parameters. From the model with three strategies, we verify that the quiet strategy could only coexists with the simple and complex strategies if the rate at which quiet males intercept females is high, which explains the rarity of the quiet strategy. We conclude that the reproductive strategy of the male frog E. pustulosus is rational.

  18. A lover or a fighter? Opposing sexual selection pressures on men's vocal pitch and facial hair.

    Science.gov (United States)

    Saxton, Tamsin K; Mackey, Lauren L; McCarty, Kristofor; Neave, Nick

    2016-01-01

    The traditional assumption within the research literature on human sexually dimorphic traits has been that many sex differences have arisen from intersexual selection. More recently, however, there has been a shift toward the idea that many male features, including male lower-pitched voices and male beard growth, might have arisen predominantly through intrasexual selection: that is, to serve the purpose of male-male competition instead of mate attraction. In this study, using a unique set of video stimuli, we measured people's perceptions of the dominance and attractiveness of men who differ both in terms of voice pitch (4 levels from lower to higher pitched) and beard growth (4 levels from clean shaven to a month's hair growth). We found a nonlinear relationship between lower pitch and increased attractiveness; men's vocal attractiveness peaked at around 96 Hz. Beard growth had equivocal effects on attractiveness judgments. In contrast, perceptions of men's dominance simply increased with increasing masculinity (i.e., with lower-pitched voices and greater beard growth). Together, these results suggest that the optimal level of physical masculinity might differ depending on whether the outcome is social dominance or mate attraction. These dual selection pressures might maintain some of the documented variability in male physical and behavioral masculinity that we see today.

  19. Selection of reference genes for quantitative real-time PCR expression studies of microdissected reproductive tissues in apomictic and sexual Boechera

    Directory of Open Access Journals (Sweden)

    Amiteye Samuel

    2011-08-01

    Full Text Available Abstract Background Apomixis, a natural form of asexual seed production in plants, is considered to have great biotechnological potential for agriculture. It has been hypothesised that de-regulation of the sexual developmental pathway could trigger apomictic reproduction. The genus Boechera represents an interesting model system for understanding apomixis, having both sexual and apomictic genotypes at the diploid level. Quantitative qRT-PCR is the most extensively used method for validating genome-wide gene expression analyses, but in order to obtain reliable results, suitable reference genes are necessary. In this work we have evaluated six potential reference genes isolated from a 454 (FLX derived cDNA library of Boechera. RNA from live microdissected ovules and anthers at different developmental stages, as well as vegetative tissues of apomictic and sexual Boechera, were used to validate the candidates. Results Based on homologies with Arabidopsis, six genes were selected from a 454 cDNA library of Boechera: RPS18 (Ribosomal sub protein 18, Efalpha1 (Elongation factor 1 alpha, ACT 2 (Actin2, UBQ (polyubiquitin, PEX4 (Peroxisomal ubiquitin conjugating enzyme and At1g09770.1 (Arabidopsis thaliana cell division cycle 5. Total RNA was extracted from 17 different tissues, qRT-PCRs were performed, and raw Ct values were analyzed for primer efficiencies and gene ratios. The geNorm and normFinder applications were used for selecting the most stable genes among all tissues and specific tissue groups (ovule, anthers and vegetative tissues in both apomictic and sexual plants separately. Our results show that BoechRPS18, BoechEfα1, BoechACT2 and BoechUBQ were the most stable genes. Based on geNorm, the combinations of BoechRPS18 and BoechEfα1 or BoechUBQ and BoechEfα1 were the most stable in the apomictic plant, while BoechRPS18 and BoechACT2 or BoechUBQ and BoechACT2 performed best in the sexual plant. When subgroups of tissue samples were analyzed

  20. Testing the prediction from sexual selection of a positive genetic correlation between human mate preferences and corresponding traits

    NARCIS (Netherlands)

    Verweij, K.J.H.; Burri, A.V.; Zietsch, B.P.

    2014-01-01

    Sexual selection can cause evolution in traits that affect mating success, and it has thus been implicated in the evolution of human physical and behavioural traits that influence attractiveness. We use a large sample of identical and nonidentical female twins to test the prediction from mate choice

  1. Sexual selection and the function of a melanin-based plumage ornament in polygamous penduline tits Remiz pendulinus

    NARCIS (Netherlands)

    Kingma, Sjouke A.; Szentirmai, Istvan; Szekely, Tamas; Bokony, Veronika; Bleeker, Maarten; Liker, Andras; Komdeur, Jan; McGraw, K.

    Melanin-based ornaments are often involved in signaling aggression and dominance, and their role in sexual selection is increasingly recognized. We investigated the functions of a melanin-based plumage ornament (facial 'mask') in male Eurasian penduline tits Remiz pendulinus in the contexts of

  2. Simultaneous selection for cowpea (Vigna unguiculata L.) genotypes with adaptability and yield stability using mixed models.

    Science.gov (United States)

    Torres, F E; Teodoro, P E; Rodrigues, E V; Santos, A; Corrêa, A M; Ceccon, G

    2016-04-29

    The aim of this study was to select erect cowpea (Vigna unguiculata L.) genotypes simultaneously for high adaptability, stability, and yield grain in Mato Grosso do Sul, Brazil using mixed models. We conducted six trials of different cowpea genotypes in 2005 and 2006 in Aquidauana, Chapadão do Sul, Dourados, and Primavera do Leste. The experimental design was randomized complete blocks with four replications and 20 genotypes. Genetic parameters were estimated by restricted maximum likelihood/best linear unbiased prediction, and selection was based on the harmonic mean of the relative performance of genetic values method using three strategies: selection based on the predicted breeding value, having considered the performance mean of the genotypes in all environments (no interaction effect); the performance in each environment (with an interaction effect); and the simultaneous selection for grain yield, stability, and adaptability. The MNC99542F-5 and MNC99-537F-4 genotypes could be grown in various environments, as they exhibited high grain yield, adaptability, and stability. The average heritability of the genotypes was moderate to high and the selective accuracy was 82%, indicating an excellent potential for selection.

  3. Complementary effect of natural and sexual selection against immigrants maintains differentiation between locally adapted fish

    Science.gov (United States)

    Plath, Martin; Riesch, Rüdiger; Oranth, Alexandra; Dzienko, Justina; Karau, Nora; Schießl, Angela; Stadler, Stefan; Wigh, Adriana; Zimmer, Claudia; Arias-Rodriguez, Lenin; Schlupp, Ingo; Tobler, Michael

    2010-08-01

    Adaptation to ecologically heterogeneous environments can drive speciation. But what mechanisms maintain reproductive isolation among locally adapted populations? Using poeciliid fishes in a system with naturally occurring toxic hydrogen sulfide, we show that (a) fish from non-sulfidic sites ( Poecilia mexicana) show high mortality (95 %) after 24 h when exposed to the toxicant, while locally adapted fish from sulfidic sites ( Poecilia sulphuraria) experience low mortality (13 %) when transferred to non-sulfidic water. (b) Mate choice tests revealed that P. mexicana females exhibit a preference for conspecific males in non-sulfidic water, but not in sulfidic water, whereas P. sulphuraria females never showed a preference. Increased costs of mate choice in sulfidic, hypoxic water, and the lack of selection for reinforcement due to the low survival of P. mexicana may explain the absence of a preference in P. sulphuraria females. Taken together, our study may be the first to demonstrate independent—but complementary—effects of natural and sexual selection against immigrants maintaining differentiation between locally adapted fish populations.

  4. A lover or a fighter? Opposing sexual selection pressures on men?s vocal pitch and facial hair

    OpenAIRE

    Saxton, Tamsin K.; Mackey, Lauren L.; McCarty, Kristofor; Neave, Nick

    2015-01-01

    The traditional assumption within the research literature on human sexually dimorphic traits has been that many sex differences have arisen from intersexual selection. More recently however, there has been a shift towards the idea that many male features, including for example male lower-pitched voices, and male beard growth, might have arisen predominantly through intrasexual selection: that is, to serve the purpose of male-male competition instead of mate attraction. In this study, using a ...

  5. Phenology of scramble polygyny in a wild population of chrysomelid beetles: the opportunity for and the strength of sexual selection [corrected].

    Directory of Open Access Journals (Sweden)

    Martha Lucía Baena

    Full Text Available Recent debate has highlighted the importance of estimating both the strength of sexual selection on phenotypic traits, and the opportunity for sexual selection. We describe seasonal fluctuations in mating dynamics of Leptinotarsa undecimlineata (Coleoptera: Chrysomelidae. We compared several estimates of the opportunity for, and the strength of, sexual selection and male precopulatory competition over the reproductive season. First, using a null model, we suggest that the ratio between observed values of the opportunity for sexual selections and their expected value under random mating results in unbiased estimates of the actual nonrandom mating behavior of the population. Second, we found that estimates for the whole reproductive season often misrepresent the actual value at any given time period. Third, mating differentials on male size and mobility, frequency of male fighting and three estimates of the opportunity for sexual selection provide contrasting but complementary information. More intense sexual selection associated to male mobility, but not to male size, was observed in periods with high opportunity for sexual selection and high frequency of male fights. Fourth, based on parameters of spatial and temporal aggregation of female receptivity, we describe the mating system of L. undecimlineata as a scramble mating polygyny in which the opportunity for sexual selection varies widely throughout the season, but the strength of sexual selection on male size remains fairly weak, while male mobility inversely covaries with mating success. We suggest that different estimates for the opportunity for, and intensity of, sexual selection should be applied in order to discriminate how different behavioral and demographic factors shape the reproductive dynamic of populations.

  6. Diet selection and seasonal dietary switch of a large sexually dimorphic herbivore

    Science.gov (United States)

    Shannon, Graeme; Mackey, Robin L.; Slotow, Rob

    2013-01-01

    Although diet selection and the physiological adaptations of grazers and browsers have been widely studied, much less is known about mixed-feeders that target both grass and woody species. The ability to switch diet allows the individual to respond to spatial and temporal changes in forage abundance and quality, providing a key mechanism for large herbivores to exploit heterogeneous environments. We compare diet selection and timing of the seasonal dietary switch for a large-bodied, sexually dimorphic mixed-feeder, the African elephant. The study was carried out on a small population of elephants (n = 48) in the Pongola Game Reserve (PGR), South Africa. Sex-specific dietary composition evaluated from feeding behaviour correlated with composition in dung samples from individuals of known sex. Grass was strongly preferred during the wet season and browse in the winter dry season. However, adult male elephants switched from browse to grass earlier, and consumed a greater overall proportion of grass in their diet, compared with adult females and their associated family groups. Male elephants also spent more time in grassland habitats, and expanded their ranges to a greater extent than females following the end of the dry season. Our results suggest that smaller adult body size, high nutritional demands of offspring, and the constraints of sociality have contributed to female elephants in PGR resolving their diet selection strategies to target higher quality foraging opportunities, whilst males appear to be adopting a rate maximizing approach. The behavioural differences between the sexes are pronounced, which has implications for elephant management approaches that are typically focussed at the population level.

  7. Surgical options for lumbosacral fusion: biomechanical stability, advantage, disadvantage and affecting factors in selecting options.

    Science.gov (United States)

    Yoshihara, Hiroyuki

    2014-07-01

    Numerous surgical procedures and instrumentation techniques for lumbosacral fusion (LSF) have been developed. This is probably because of its high mechanical demand and unique anatomy. Surgical options include anterior column support (ACS) and posterior stabilization procedures. Biomechanical studies have been performed to verify the stability of those options. The options have their own advantage but also disadvantage aspects. This review article reports the surgical options for lumbosacral fusion, their biomechanical stability, advantages/disadvantages, and affecting factors in option selection. Review of literature. LSF has lots of options both for ACS and posterior stabilization procedures. Combination of posterior stabilization procedures is an option. Furthermore, combinations of ACS and posterior stabilization procedures are other options. It is difficult to make a recommendation or treatment algorithm of LSF from the current literature. However, it is important to know all aspects of the options and decision-making of surgical options for LSF needs to be tailored for each patient, considering factors such as biomechanical stress and osteoporosis.

  8. Mating systems and sexual selection in male-pregnant pipefishes and seahorses: insights from microsatellite-based studies of maternity.

    Science.gov (United States)

    Jones, A G; Avise, J C

    2001-01-01

    In pipefishes and seahorses (family Syngnathidae), the males provide all postzygotic care of offspring by brooding embryos on their ventral surfaces. In some species, this phenomenon of male "pregnancy" results in a reversal of the usual direction of sexual selection, such that females compete more than males for access to mates, and secondary sexual characteristics evolve in females. Thus the syngnathids can provide critical tests of theories related to the evolution of sex differences and sexual selection. Microsatellite-based studies of the genetic mating systems of several species of pipefishes and seahorses have provided insights into important aspects of the natural history and evolution of these fishes. First, males of species with completely enclosed pouches have complete confidence of paternity, as might be predicted from parental investment theory for species in which males invest so heavily in offspring. Second, a wide range of genetic mating systems have been documented in nature, including genetic monogamy in a seahorse, polygynandry in two species of pipefish, and polyandry in a third pipefish species. The genetic mating systems appear to be causally related to the intensity of sexual selection, with secondary sex characters evolving most often in females of the more polyandrous species. Third, genetic studies of captive-breeding pipefish suggest that the sexual selection gradient (or Bateman gradient) may be a substantially better method for characterizing the mating system than previously available techniques. Finally, these genetic studies of syngnathid mating systems have led to some general insights into the occurrence of clustered mutations at microsatellite loci, the utility of linked loci in studies of parentage, and the use of parentage data for direct estimation of adult population size.

  9. Ornament Complexity Is Correlated with Sexual Selection: (A Comment on Raia et al., "Cope's Rule and the Universal Scaling Law of Ornament Complexity").

    Science.gov (United States)

    Holman, Luke; Bro-Jørgensen, Jakob

    2016-08-01

    Raia et al. propose that the evolution of the shape and complexity of animal ornaments (e.g., deer antlers) can be explained by interspecific variation in body size and is not influenced by sexual selection. They claim to show that ornament complexity is related to body size by an 0.25-power law and argue that this finding precludes a role for sexual selection in the evolution of ornament complexity. However, their study does not test alternative hypotheses and mismeasures antler shape allometry by omitting much of the published data. We show that an index of sexual selection (sexual size dimorphism) is positively correlated with size-corrected antler complexity and that the allometric slope of complexity is substantially greater than 0.25, contra Raia et al. We conclude that sexual selection and physical constraints both affect the evolution of antler shape.

  10. A two-locus model of spatially varying stabilizing or directional selection on a quantitative trait.

    Science.gov (United States)

    Geroldinger, Ludwig; Bürger, Reinhard

    2014-06-01

    The consequences of spatially varying, stabilizing or directional selection on a quantitative trait in a subdivided population are studied. A deterministic two-locus two-deme model is employed to explore the effects of migration, the degree of divergent selection, and the genetic architecture, i.e., the recombination rate and ratio of locus effects, on the maintenance of genetic variation. The possible equilibrium configurations are determined as functions of the migration rate. They depend crucially on the strength of divergent selection and the genetic architecture. The maximum migration rates are investigated below which a stable fully polymorphic equilibrium or a stable single-locus polymorphism can exist. Under stabilizing selection, but with different optima in the demes, strong recombination may facilitate the maintenance of polymorphism. However usually, and in particular with directional selection in opposite direction, the critical migration rates are maximized by a concentrated genetic architecture, i.e., by a major locus and a tightly linked minor one. Thus, complementing previous work on the evolution of genetic architectures in subdivided populations subject to diversifying selection, it is shown that concentrated architectures may aid the maintenance of polymorphism. Conditions are obtained when this is the case. Finally, the dependence of the phenotypic variance, linkage disequilibrium, and various measures of local adaptation and differentiation on the parameters is elaborated. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Mice selectively bred for open-field thigmotaxis: life span and stability of the selection trait.

    Science.gov (United States)

    Leppänen, Pia K; Ewalds-Kvist, S Béatrice M; Selander, Ritva-Kajsa

    2005-04-01

    In 2 experiments, the authors examined 69 mice selectively bred for high or low levels of open-field (OF) thigmotactic behavior (high open-field thigmotaxis [HOFT] and low open-field thigmotaxis [LOFT], respectively). They found that the strains differed in defecation during the 60-min exposure to the OF. Furthermore, the strains differed with regard to their life spans: The more thigmotactic HOFT mice lived longer than the LOFT mice. The strains were not differentiated by food intake or excretion. The strain difference in thigmotaxis was not age dependent, and it persisted in the home-cage condition as well. Neither the location (center or wall) of the starting point nor the shape (circular or square) of the OF arena affected the difference in wall-seeking behavior between the two strains. The authors concluded that the difference in thigmotaxis (or emotionality) between the HOFT and LOFT mice is a stable and robust feature of these animals.

  12. Does Sexual Selection Influence Ornamentation of Hemipenes in Old World Snakes?

    Science.gov (United States)

    Andonov, Kostadin; Natchev, Nikolay; Kornilev, Yurii V; Tzankov, Nikolay

    2017-09-01

    In the present study, we investigated and documented the morphology of the male copulatory organs (hemipenes) in fifteen wide-ranging snake species. The species represent four families (Boidae, Colubridae, Lamprophiidae, and Viperidae) and ten genera. We applied the same preparation techniques for all species, successfully everting and expanding the organs completely. The detailed description of the general morphology of the male copulatory organs was based on 31 specimens. Our data were compared with published observations and we point out some incorrectly described details in previous investigations. We provide the first description of the hemipenial morphology for three ophidian species (Elaphe sauromates, Telescopus fallax, and Malpolon insignitus). In addition to the morphological characteristics of the hemipenes presented in the research, we propose the adoption of a standardized index describing the hemipenial proportions. The immense variation in hemipenial morphology presupposes its dynamic evolution, but we suggest that many of the significant structures observed here may have escaped previous researchers due to differing methodologies. Some of the highly ornamented morphologies that we describe are consistent with a locking mechanism during copulation. However, other morphologies may relate to the variety of mating behaviors observed. As a result, we propose that sexual selection is the major driver affecting the hemipenial ornamentation in snakes. Anat Rec, 300:1680-1694, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  13. Mechanisms of rapid sympatric speciation by sex reversal and sexual selection in cichlid fish.

    Science.gov (United States)

    Lande, R; Seehausen, O; van Alphen, J J

    2001-01-01

    Mechanisms of speciation in cichlid fish were investigated by analyzing population genetic models of sexual selection on sex-determining genes associated with color polymorphisms. The models are based on a combination of laboratory experiments and field observations on the ecology, male and female mating behavior, and inheritance of sex-determination and color polymorphisms. The models explain why sex-reversal genes that change males into females tend to be X-linked and associated with novel colors, using the hypothesis of restricted recombination on the sex chromosomes, as suggested by previous theory on the evolution of recombination. The models reveal multiple pathways for rapid sympatric speciation through the origin of novel color morphs with strong assortative mating that incorporate both sex-reversal and suppressor genes. Despite the lack of geographic isolation or ecological differentiation, the new species coexists with the ancestral species either temporarily or indefinitely. These results may help to explain different patterns and rates of speciation among groups of cichlids, in particular the explosive diversification of rock-dwelling haplochromine cichlids.

  14. Sexual Orientation and Spatial Position Effects on Selective Forms of Object Location Memory

    Science.gov (United States)

    Rahman, Qazi; Newland, Cherie; Smyth, Beatrice Mary

    2011-01-01

    Prior research has demonstrated robust sex and sexual orientation-related differences in object location memory in humans. Here we show that this sexual variation may depend on the spatial position of target objects and the task-specific nature of the spatial array. We tested the recovery of object locations in three object arrays (object…

  15. Differential Nanos 2 protein stability results in selective germ cell accumulation in the sea urchin.

    Science.gov (United States)

    Oulhen, Nathalie; Wessel, Gary M

    2016-10-01

    Nanos is a translational regulator required for the survival and maintenance of primordial germ cells. In the sea urchin, Strongylocentrotus purpuratus (Sp), Nanos 2 mRNA is broadly transcribed but accumulates specifically in the small micromere (sMic) lineage, in part because of the 3'UTR element GNARLE leads to turnover in somatic cells but retention in the sMics. Here we found that the Nanos 2 protein is also selectively stabilized; it is initially translated throughout the embryo but turned over in the future somatic cells and retained only in the sMics, the future germ line in this animal. This differential stability of Nanos protein is dependent on the open reading frame (ORF), and is independent of the sumoylation and ubiquitylation pathways. Manipulation of the ORF indicates that 68 amino acids in the N terminus of the Nanos protein are essential for its stability in the sMics whereas a 45 amino acid element adjacent to the zinc fingers targets its degradation. Further, this regulation of Nanos protein is cell autonomous, following formation of the germ line. These results are paradigmatic for the unique presence of Nanos in the germ line by a combination of selective RNA retention, distinctive translational control mechanisms (Oulhen et al., 2013), and now also by defined Nanos protein stability. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Stability of selected volatile contact allergens in different patch test chambers under different storage conditions

    DEFF Research Database (Denmark)

    Mose, Kristian Fredløv; Andersen, Klaus Ejner; Christensen, Lars Porskjaer

    2012-01-01

    Background. Patch test preparations of volatile substances may evaporate during storage, thereby giving rise to reduced patch test concentrations. Objectives. To investigate the stability of selected acrylates/methacrylates and fragrance allergens in three different test chambers under different...... both storage conditions, whereas MMA and 2-HPA required cool storage for maintenance of the limit. Conclusion. The Van der Bend® transport container was the best device for storage of samples of volatile contact allergens....

  17. Maximizing mandibular prosthesis stability utilizing linear occlusion, occlusal plane selection, and centric recording.

    Science.gov (United States)

    Williamson, Richard A; Williamson, Anne E; Bowley, John; Toothaker, Randy

    2004-03-01

    The stability of mandibular complete dentures may be improved by reducing the transverse forces on the denture base through linear (noninterceptive) occlusion, selecting an occlusal plane that reduces horizontal vectors of force at occlusal contact, and utilizing a central bearing intraoral gothic arch tracing to record jaw relations. This article is intended to acquaint the reader with one technique for providing stable complete denture prostheses using the aforementioned materials, devices, and procedures.

  18. An expressed sequence tag (EST) library for Drosophila serrata, a model system for sexual selection and climatic adaptation studies

    OpenAIRE

    Frentiu, Francesca D; Adamski, Marcin; McGraw, Elizabeth A; Blows, Mark W; Chenoweth, Stephen F

    2009-01-01

    Abstract Background The native Australian fly Drosophila serrata belongs to the highly speciose montium subgroup of the melanogaster species group. It has recently emerged as an excellent model system with which to address a number of important questions, including the evolution of traits under sexual selection and traits involved in climatic adaptation along latitudinal gradients. Understanding the molecular genetic basis of such traits has been limited by a lack of genomic resources for thi...

  19. Morella serrata (Lam.) Killick stabilizes biomembrane and rejuvenates sexual competence in male Wistar rats.

    Science.gov (United States)

    Sabiu, S; Ashafa, A O T

    2017-06-09

    Morella serrata L. is an indigenous medicinal plant to South and southern Africa with folkloric applications as aphrodisiac, laxative, antimicrobial, anti-inflammatory, analgesic, anti-hypertensive, antitussive and antidiabetic agent. This study evaluated the membrane stabilization and aphrodisiac potentials of its aqueous root extract in male Wistar rats. While the membrane stabilization of the extract was investigated against bovine erythrocytes (BE), the male rats for the aphrodisiac study were randomized into five groups with animals in group 1 given sterile placebo and served as control. The rats in group 2 were treated with 7.14mg/kg body weight of PowMaxM, while animals in groups 3, 4 and 5 were administered with the extract (100, 200 and 400mg/kg, respectively). All treatments (1mL) were done once daily for 4 weeks via oral gavaging and their mating behavioural, testicular, spermatogenetic and antioxidant parameters were evaluated. With the exception of the mount, intromission and post ejaculatory latencies that were dose-dependently reduced by the extract, other mating parameters were significantly improved when compared with the control. Similar patterns of significant improvement were also observed on the testes-body weight ratio, quality and viability of sperm cells as well as testicular concentrations of proteins, cholesterol, glycogen, testosterone, follicle stimulating hormone, leuitenizing hormone and glutathione (reduced) subsequent to treatment with the extract. Although, administration of M. serrata had no significant (p>0.05) effect on the testicular activity of gamma glutamyl transferase, those of lactate dehydrogenase, phosphatases (alkaline and acid), superoxide dismutase and catalase were significantly (p<0.05) induced in the treated animals. The extract also conferred respective significant (p<0.05) membrane stabilization potential of 66.02% and 60.87% on the BE against hypotonic solution and heat-induced hemolysis relative to 62.14% and 40

  20. Assessing the accuracy and stability of variable selection methods for random forest modeling in ecology.

    Science.gov (United States)

    Fox, Eric W; Hill, Ryan A; Leibowitz, Scott G; Olsen, Anthony R; Thornbrugh, Darren J; Weber, Marc H

    2017-07-01

    Random forest (RF) modeling has emerged as an important statistical learning method in ecology due to its exceptional predictive performance. However, for large and complex ecological data sets, there is limited guidance on variable selection methods for RF modeling. Typically, either a preselected set of predictor variables are used or stepwise procedures are employed which iteratively remove variables according to their importance measures. This paper investigates the application of variable selection methods to RF models for predicting probable biological stream condition. Our motivating data set consists of the good/poor condition of n = 1365 stream survey sites from the 2008/2009 National Rivers and Stream Assessment, and a large set (p = 212) of landscape features from the StreamCat data set as potential predictors. We compare two types of RF models: a full variable set model with all 212 predictors and a reduced variable set model selected using a backward elimination approach. We assess model accuracy using RF's internal out-of-bag estimate, and a cross-validation procedure with validation folds external to the variable selection process. We also assess the stability of the spatial predictions generated by the RF models to changes in the number of predictors and argue that model selection needs to consider both accuracy and stability. The results suggest that RF modeling is robust to the inclusion of many variables of moderate to low importance. We found no substantial improvement in cross-validated accuracy as a result of variable reduction. Moreover, the backward elimination procedure tended to select too few variables and exhibited numerous issues such as upwardly biased out-of-bag accuracy estimates and instabilities in the spatial predictions. We use simulations to further support and generalize results from the analysis of real data. A main purpose of this work is to elucidate issues of model selection bias and instability to ecologists interested in

  1. Components of formalized description of selecting tools for ensuring stability of banking system

    Directory of Open Access Journals (Sweden)

    N.P. Pogorelenko

    2015-09-01

    Full Text Available A banking system is one of the key elements of a financial market of any country. Effectiveness and functional orientation of a banking system provide continuous and targeted financial resources flowing between different sectors of economy and this allows to perform economic activities of various entities. Thus, a banking system plays an essential role in the formation of market relations. A question of stable functioning of a banking system can be defined as a key one. The basic task is to improve the management of a banking system by achieving its stability. The disclosure of formalized description of the definition of tools to influence the selection procedure for ensuring stability of a banking system should be determined as the primary objective. For reaching the goal a comparative study has been introduced and generalized concerning the concept definition of «banking system» and the ideology of its management according to the circumstances and factors of influence. The combination of individual components is to determine the instruments of influence on the banking system activity in the form of chain ties. On the base of the analysis carried out the article grounds the necessity of the generalized use of formalized description of the procedures for selecting instruments for ensuring stability of a banking system. For the purpose of this procedure the author has also grounded, determined and disclosed some of its components. To implement the relevant qualitative phase of formalization the author has proposed the use of chain patterns, and to quantify the individual parameters of such a procedure the methodology of border stochastic analysis has been offered. As a scientific novelty of the present research it is necessary to note the qualitative and quantitative phases for formal presentation of describing procedures for the selection of tools to ensure banking system stability as well as the introduction of chain schemes for the

  2. Sensitivity, selectivity and stability of tin oxide nanostructures on large area arrays of microhotplates

    Science.gov (United States)

    Panchapakesan, Balaji; Cavicchi, Richard; Semancik, Steve; DeVoe, Don L.

    2006-01-01

    In this paper, the sensitivity, stability and selectivity of nanoparticle engineered tin oxide (SnO2) are reported, for microhotplate chemical sensing applications. 16 Å of metals such as nickel, cobalt, iron, copper and silver were selectively evaporated onto each column of the microhotplate array. Following evaporation, the microhotplates were heated to 500 °C and SnO2 was deposited on top of the microhotplates using a self-aligned chemical vapour deposition process. Scanning electron microscopy characterization revealed control of SnO2 nanostructures in the range of 20-121 nm. Gas sensing in seven different hydrocarbons revealed that metal nanoparticles that helped in producing faster nucleation of SnO2 resulted in smaller grain size and higher sensitivity. Sensitivity as a function of concentration and grain size is addressed for tin oxide nanostructures. Smaller grain sizes resulted in higher sensitivity of tin oxide nanostructures. Temperature programmed sensing of the devices yielded shape differences in the response between air and methanol, illustrating selectivity. Spiderweb plots were used to monitor the materials programmed selectivity. The shape differences between different gases in spiderweb plots illustrate materials selectivity as a powerful mapping approach for monitoring selectivity in various gases. Continuous monitoring in 80 ppm methanol yielded stable sensor response for more than 200 h. This comprehensive study illustrates the use of a nanoparticle engineering approach for sensitive, selective and stable gas sensing applications.

  3. Quantitative measures of sexual selection reveal no evidence for sex-role reversal in a sea spider with prolonged paternal care

    OpenAIRE

    Barreto, Felipe S.; Avise, John C.

    2010-01-01

    Taxa in which males alone invest in postzygotic care of offspring are often considered good models for investigating the proffered relationships between sexual selection and mating systems. In the pycnogonid sea spider Pycnogonum stearnsi, males carry large egg masses on their bodies for several weeks, so this species is a plausible candidate for sex-role reversal (greater intensity of sexual selection on females than on males). Here, we couple a microsatellite-based assessment of the mating ...

  4. A comparison of rapists and sexual murderers on demographic and selected psychometric measures.

    Science.gov (United States)

    Oliver, Caroline J; Beech, Anthony R; Fisher, Dawn; Beckett, Richard

    2007-06-01

    This study compared 58 sexual murderers and 112 rapists who were about to undergo treatment in prison for their sexual offending behavior. The two groups were compared on background, personality, offense, and victim characteristics. The sexual murderer group were less likely to have been involved in a relationship at the time of their index offense, generally attacked older victims, and had higher self-esteem. The rapist sample were found to have more violent previous convictions and scored higher on measures of historical deviance (nonsexual), paranoid suspicion, and resentment. No differences were found on the personality or clinical syndrome scales of the Millon Clinical Multiaxial Inventory-III. However, the rapist sample had significantly higher mean scores on the Paranoid Suspicion, Resentment, and Self-Esteem subscales of the Antisocial Personality Questionnaire. Future research should compare the two groups on dynamic or changeable factors to determine differential treatment needs.

  5. The relative nature of fertilization success: Implications for the study of post-copulatory sexual selection

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    García-González Francisco

    2008-05-01

    Full Text Available Abstract Background The determination of genetic variation in sperm competitive ability is fundamental to distinguish between post-copulatory sexual selection models based on good-genes vs compatible genes. The sexy-sperm and the good-sperm hypotheses for the evolution of polyandry require additive (intrinsic effects of genes influencing sperm competitiveness, whereas the genetic incompatibility hypothesis invokes non-additive genetic effects. A male's sperm competitive ability is typically estimated from his fertilization success, a measure that is dependent on the ability of rival sperm competitors to fertilize the ova. It is well known that fertilization success may be conditional to genotypic interactions among males as well as between males and females. However, the consequences of effects arising from the random sampling of sperm competitors upon the estimation of genetic variance in sperm competitiveness have been overlooked. Here I perform simulations of mating trials performed in the context of sibling analysis to investigate whether the ability to detect additive genetic variance underlying the sperm competitiveness phenotype is hindered by the relative nature of fertilization success measurements. Results Fertilization success values render biased sperm competitive ability values. Furthermore, asymmetries among males in the errors committed when estimating sperm competitive abilities are likely to exist as long as males exhibit variation in sperm competitiveness. Critically, random effects arising from the relative nature of fertilization success lead to an underestimation of underlying additive genetic variance in sperm competitive ability. Conclusion The results show that, regardless of the existence of genotypic interactions affecting the output of sperm competition, fertilization success is not a perfect predictor of sperm competitive ability because of the stochasticity of the background used to obtain fertilization success

  6. Sex linkage, sex-specific selection, and the role of recombination in the evolution of sexually dimorphic gene expression.

    Science.gov (United States)

    Connallon, Tim; Clark, Andrew G

    2010-12-01

    Sex-biased genes--genes that are differentially expressed within males and females--are nonrandomly distributed across animal genomes, with sex chromosomes and autosomes often carrying markedly different concentrations of male- and female-biased genes. These linkage patterns are often gene- and lineage-dependent, differing between functional genetic categories and between species. Although sex-specific selection is often hypothesized to shape the evolution of sex-linked and autosomal gene content, population genetics theory has yet to account for many of the gene- and lineage-specific idiosyncrasies emerging from the empirical literature. With the goal of improving the connection between evolutionary theory and a rapidly growing body of genome-wide empirical studies, we extend previous population genetics theory of sex-specific selection by developing and analyzing a biologically informed model that incorporates sex linkage, pleiotropy, recombination, and epistasis, factors that are likely to vary between genes and between species. Our results demonstrate that sex-specific selection and sex-specific recombination rates can generate, and are compatible with, the gene- and species-specific linkage patterns reported in the genomics literature. The theory suggests that sexual selection may strongly influence the architectures of animal genomes, as well as the chromosomal distribution of fixed substitutions underlying sexually dimorphic traits. © 2010 The Author(s). Evolution© 2010 The Society for the Study of Evolution.

  7. Stability of selected volatile contact allergens in different patch test chambers under different storage conditions.

    Science.gov (United States)

    Mose, Kristian F; Andersen, Klaus E; Christensen, Lars Porskjaer

    2012-04-01

    Patch test preparations of volatile substances may evaporate during storage, thereby giving rise to reduced patch test concentrations. To investigate the stability of selected acrylates/methacrylates and fragrance allergens in three different test chambers under different storage conditions. Petrolatum samples of methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (2-HEMA), 2-hydroxypropyl acrylate (2-HPA), cinnamal and eugenol in patch test concentrations were stored in three different test chambers (IQ chamber™, IQ Ultimate™, and Van der Bend® transport container) at room temperature and in a refrigerator. The samples were analysed in triplicate with high-performance liquid chromatography. The decrease in concentration was substantial for all five allergens under both storage conditions in IQ chamber™ and IQ Ultimate™, with the exception of 2-HEMA during storage in the refrigerator. For these two chamber systems, the contact allergen concentration dropped below the stability limit in the following order: MMA, cinnamal, 2-HPA, eugenol, and 2-HEMA. In the Van der Bend® transport container, the contact allergens exhibited acceptable stability under both storage conditions, whereas MMA and 2-HPA required cool storage for maintenance of the limit. The Van der Bend® transport container was the best device for storage of samples of volatile contact allergens. © 2012 John Wiley & Sons A/S.

  8. Genetic and non-genetic factors affecting rabbit doe sexual receptivity as estimated from one generation of divergent selection

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    M. Theau.Clément

    2015-09-01

    Full Text Available Sexual receptivity of rabbit does at insemination greatly influences fertility and is generally induced by hormones or techniques known as “biostimulation”. Searching for more sustainable farming systems, an original alternative would be to utilise the genetic pathway to increase the does’receptivity. The purpose of the present study was to identify genetic and non-genetic factors that influence rabbit doe sexual receptivity, in the context of a divergent selection experiment over 1 generation. The experiment spanned 2 generations: the founder generation (G0 consisting of 140 rabbit does, and the G1 generation comprising 2 divergently selected lines (L and H lines with 70 does each and 2 successive batches from each generation. The selection rate of the G0 females to form the G1 lines was 24/140. The selection tests consisted of 16 to 18 successive receptivity tests at the rate of 3 tests per week. On the basis of 4716 tests from 275 females, the average receptivity was 56.6±48.2%. A batch effect and a test operator effect were revealed. The contribution of females to the total variance was 20.0%, whereas that of bucks was only 1.1%. Throughout the experiment, 18.2% of does expressed a low receptivity (< 34%, 50.7% a medium one and 33.1% a high one (>66%. Some does were frequently receptive, whereas others were rarely receptive. The repeatability of sexual receptivity was approximately 20%. The results confirmed the high variability of sexual receptivity of non-lactating rabbit does maintained without any biostimulation or hormonal treatment. A lack of selection response on receptivity was observed. Accordingly, the heritability of receptivity was estimated at 0.01±0.02 from an animal model and at 0.02±0.03 from a  sire and dam model. The heritability of the average receptivity of a doe was calculated as 0.04. In agreement with the low estimated heritability, the heritability determined was no different from zero

  9. Adolescents' and their friends' sexual behavior and intention: Selection effects of personality dimensions

    NARCIS (Netherlands)

    Baams, L.; Overbeek, G.; van de Bongardt, D.; Reitz, E.; Dubas, J.S.; van Aken, M.A.G.

    2015-01-01

    Using simulation investigation for empirical network analyses (in RSiena) we examined how personality and sexual behavior and intention were related to peer processes in Dutch adolescents. Our main research questions were: (a) do adolescents cluster together in friendship networks based on

  10. Adolescents' and their friends' sexual behavior and intention : Selection effects of personality dimensions

    NARCIS (Netherlands)

    Baams, Laura; Overbeek, Geertjan; van de Bongardt, Daphne; Reitz, Ellen; Dubas, Judith Semon; van Aken, Marcel A G

    2015-01-01

    Using simulation investigation for empirical network analyses (in RSiena) we examined how personality and sexual behavior and intention were related to peer processes in Dutch adolescents. Our main research questions were: (a) do adolescents cluster together in friendship networks based on

  11. Mutual ornamentation, sexual selection, and social dominance in the black swan

    NARCIS (Netherlands)

    Kraaijeveld, K; Gregurke, J; Hall, C; Komdeur, J; Mulder, RA

    We investigated the adaptive significance of a sexually monomorphic ornament in the black swan Cygnus atratus. Both sexes grow curled feathers on their wings (range 7-22 curled feathers per wing), which are displayed prominently in a range of social interactions. The number of curled feathers

  12. Disgust sensitivity selectively predicts attitudes toward groups that threaten (or uphold) traditional sexual morality

    NARCIS (Netherlands)

    Crawford, J.; Inbar, Y.; Malony, V.

    2014-01-01

    Previous research has linked disgust sensitivity to negative attitudes toward gays and lesbians. We extend this existing research by examining the extent to which disgust sensitivity predicts attitudes more generally toward groups that threaten or uphold traditional sexual morality. In a sample of

  13. Responding to Parental Objections to School Sexuality Education: A Selection of 12 Objections

    Science.gov (United States)

    Goldman, Juliette D. G.

    2008-01-01

    Sexuality education for school-aged young people is a crucial component of all quality education systems. It prepares young people for participation in society as responsible, mature and community-minded citizens. Most contemporary school education curricula generally aim to enhance young people's knowledge, skills and understandings of the world,…

  14. Genetic parameters and simultaneous selection for root yield, adaptability and stability of cassava genotypes

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    João Tomé de Farias Neto

    2013-12-01

    Full Text Available The objective of this work was to estimate genetic parameters and to evaluate simultaneous selection for root yield and for adaptability and stability of cassava genotypes. The effects of genotypes were assumed as fixed and random, and the mixed model methodology (REML/Blup was used to estimate genetic parameters and the harmonic mean of the relative performance of genotypic values (HMRPGV, for simultaneous selection purposes. Ten genotypes were analyzed in a complete randomized block design, with four replicates. The experiment was carried out in the municipalities of Altamira, Santarém, and Santa Luzia do Pará in the state of Pará, Brazil, in the growing seasons of 2009/2010, 2010/2011, and 2011/2012. Roots were harvested 12 months after planting, in all tested locations. Root yield had low coefficients of genotypic variation (4.25% and broad-sense heritability of individual plots (0.0424, which resulted in low genetic gain. Due to the low genotypic correlation (0.15, genotype classification as to root yield varied according to the environment. Genotypes CPATU 060, CPATU 229, and CPATU 404 stood out as to their yield, adaptability, and stability.

  15. Optimality and stability of symmetric evolutionary games with applications in genetic selection.

    Science.gov (United States)

    Huang, Yuanyuan; Hao, Yiping; Wang, Min; Zhou, Wen; Wu, Zhijun

    2015-06-01

    Symmetric evolutionary games, i.e., evolutionary games with symmetric fitness matrices, have important applications in population genetics, where they can be used to model for example the selection and evolution of the genotypes of a given population. In this paper, we review the theory for obtaining optimal and stable strategies for symmetric evolutionary games, and provide some new proofs and computational methods. In particular, we review the relationship between the symmetric evolutionary game and the generalized knapsack problem, and discuss the first and second order necessary and sufficient conditions that can be derived from this relationship for testing the optimality and stability of the strategies. Some of the conditions are given in different forms from those in previous work and can be verified more efficiently. We also derive more efficient computational methods for the evaluation of the conditions than conventional approaches. We demonstrate how these conditions can be applied to justifying the strategies and their stabilities for a special class of genetic selection games including some in the study of genetic disorders.

  16. Drug facilitated sexual assault: detection and stability of benzodiazepines in spiked drinks using gas chromatography-mass spectrometry.

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    Lata Gautam

    Full Text Available Benzodiazepines are detected in a significant number of drug facilitated sexual assaults (DFSA. Whilst blood and urine from the victim are routinely analysed, due to the delay in reporting DFSA cases and the short half lives of most of these drugs in blood and urine, drug detection in such samples is problematic. Consideration of the drinks involved and analysis for drugs may start to address this. Here we have reconstructed the 'spiking' of three benzodiazepines (diazepam, flunitrazepam and temazepam into five drinks, an alcopop (flavoured alcoholic drink, a beer, a white wine, a spirit, and a fruit based non-alcoholic drink (J2O chosen as representative of those drinks commonly used by women in 16-24 year old age group. Using a validated GC-MS method for the simultaneous detection of these drugs in the drinks we have studied the storage stability of the benzodiazepines under two different storage conditions, uncontrolled room temperature and refrigerator (4°C over a 25 day period. All drugs could be detected in all beverages over this time period. Diazepam was found to be stable in all of the beverages, except the J2O, under both storage conditions. Flunitrazepam and temazepam were found not to be stable but were detectable (97% loss of temazepam and 39% loss of flunitrazepam from J2O. The recommendations from this study are that there should be a policy change and that drinks thought to be involved in DFSA cases should be collected and analysed wherever possible to support other evidence types.

  17. Differences in the Selection Bottleneck between Modes of Sexual Transmission Influence the Genetic Composition of the HIV-1 Founder Virus.

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    Damien C Tully

    2016-05-01

    Full Text Available Due to the stringent population bottleneck that occurs during sexual HIV-1 transmission, systemic infection is typically established by a limited number of founder viruses. Elucidation of the precise forces influencing the selection of founder viruses may reveal key vulnerabilities that could aid in the development of a vaccine or other clinical interventions. Here, we utilize deep sequencing data and apply a genetic distance-based method to investigate whether the mode of sexual transmission shapes the nascent founder viral genome. Analysis of 74 acute and early HIV-1 infected subjects revealed that 83% of men who have sex with men (MSM exhibit a single founder virus, levels similar to those previously observed in heterosexual (HSX transmission. In a metadata analysis of a total of 354 subjects, including HSX, MSM and injecting drug users (IDU, we also observed no significant differences in the frequency of single founder virus infections between HSX and MSM transmissions. However, comparison of HIV-1 envelope sequences revealed that HSX founder viruses exhibited a greater number of codon sites under positive selection, as well as stronger transmission indices possibly reflective of higher fitness variants. Moreover, specific genetic "signatures" within MSM and HSX founder viruses were identified, with single polymorphisms within gp41 enriched among HSX viruses while more complex patterns, including clustered polymorphisms surrounding the CD4 binding site, were enriched in MSM viruses. While our findings do not support an influence of the mode of sexual transmission on the number of founder viruses, they do demonstrate that there are marked differences in the selection bottleneck that can significantly shape their genetic composition. This study illustrates the complex dynamics of the transmission bottleneck and reveals that distinct genetic bottleneck processes exist dependent upon the mode of HIV-1 transmission.

  18. The form of sexual selection arising from male-male competition depends on the presence of females in the social environment.

    Science.gov (United States)

    Procter, D S; Moore, A J; Miller, C W

    2012-05-01

    Sexual selection arises from social interactions, and if social environments vary so too should sexual selection. For example, male-male competition often occurs either in the presence or in the absence of females, and such changes in the social environment could affect the form and strength of sexual selection. Here we examine how the presence of a female influences selection arising from male-male competition in a leaf-footed cactus bug, Narnia femorata, which has a resource defence mating system. Males compete for territories on cacti because females lay eggs on the cactus plants. Females are not always present when this competition first occurs; however, the presence or absence of the female matters. We found that both the form and strength of selection on male traits, those traits that influenced success in intrasexual competition, depended on the social context. When a female was not present, male size and the area of the sexually dimorphic hind legs was only marginally important to winning a contest. However, males with larger overall size and leg area were more likely to win in the presence of a female. There was also positive quadratic selection on these traits when a female was present with both the largest and the smallest males winning. The implication is unexpected alternative strategies when females are present. Our results support the notion that sexual selection should be studied under all relevant social contexts. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

  19. Reinforcement learning modulates the stability of cognitive control settings for object selection

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    Anthony William Sali

    2013-12-01

    Full Text Available Cognitive flexibility reflects both a trait that reliably differs between individuals and a state that can fluctuate moment-to-moment. Whether individuals can undergo persistent changes in cognitive flexibility as a result of reward learning is less understood. Here, we investigated whether reinforcing a periodic shift in an object selection strategy can make an individual more prone to switch strategies in a subsequent unrelated task. Participants completed two different choice tasks in which they selected one of four objects in an attempt to obtain a hidden reward on each trial. During a training phase, objects were defined by color. Participants received either consistent reward contingencies in which one color was more often rewarded, or contingencies in which the color that was more often rewarded changed periodically and without warning. Following the training phase, all participants completed a test phase in which reward contingencies were defined by spatial location and the location that was more often rewarded remained constant across the entire task. Those participants who received inconsistent contingencies during training continued to make more variable selections during the test phase in comparison to those who received the consistent training. Furthermore, a difference in the likelihood to switch selections on a trial-by-trial basis emerged between training groups: participants who received consistent contingencies during training were less likely to switch object selections following an unrewarded trial and more likely to repeat a selection following reward. Our findings provide evidence that the extent to which priority shifting is reinforced modulates the stability of cognitive control settings in a persistent manner, such that individuals become generally more or less prone to shifting priorities in the future.

  20. Sexually selected nest-building--Pomatoschistus minutus males build smaller nest-openings in the presence of sneaker males.

    Science.gov (United States)

    Svensson, O; Kvarnemo, C

    2003-09-01

    Both natural selection and sexual selection may act on nest-building. We tested experimentally how different regimes of egg-predation and male-male competition influence nest-building before mating, using the marine fish sand goby, Pomatoschistus minutus. Males with sneaker males present built the smallest nest-openings, smaller than males held alone or with Pomatoschistus microps males (which may predate eggs and compete over nest-sites but not compete over fertilizations). Males with visual access to other nest-building males tended also to build smaller openings than males held alone or with P. microps. Males with egg-predators present built nests with openings not differing significantly from any other treatment. Our results indicate that the small nest-openings found in the sneaker male treatment are sexually selected through protection against sneaking or by female choice. Across treatments, time span before a male started to build his nest also explained variation in nest-opening width; males starting late built larger nest-openings.

  1. Legal size limit implies strong fisheries selection on sexually selected traits in a temperate wrasse providing male-only parental care

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    Kim Aleksander Tallaksen Halvorsen

    2015-12-01

    Full Text Available Corkwing wrasse (Symphodus melops is a temperate wrasse displaying both sex and male dimorphism and is targeted in a size selective commercial fishery which has increased dramatically since 2008. Wrasses are supplied alive to salmon farms as cleaner fish to combat infestations of Salmon lice. In previous studies, growth and maturation has been found to differ among male morphs and sexes and these groups might therefore be targeted unevenly by the size selective fishery. In the present study, we address this by comparing size regulations and fishing practice with data on sex specific growth and maturation from Western and Southern Norway, two regions varying in density and life histories. Two years of field data on density and length measures was used together with a subsample of otoliths to determine sex specific growth patterns. In the region with high density, nesting males were found to grow faster and mature later than sneaker males and females. Here, most nesting males will reach the minimum size as juveniles, one and two years before females and sneakers respectively. In contrast, sexual dimorphism was much less pronounced in the low density region, and relaxed male-male competition over nesting sites seems a likely explanation for this pattern. Intensive harvesting with selective removal of the larger nesting males could potentially lead to short term effect such as sperm limitation and reduced offspring survival and thus affect the productivity of juveniles. In addition, the current fishing regime may select for reduced growth rates and earlier maturation and oppose sexual selection.

  2. Why Creativity is Sexy: A Review of the Evidence of Sexual Selection for Creative Abilities in Humans

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    Stoyo Karamihalev

    2013-08-01

    Full Text Available Creativity is an essential human trait, yet there is no consensus among scholars as to why our species have developed creative abilities. Most evolutionary explanations rely on the survival value of such abilities, but generally fail to explain why other species have not evolved similar capacities or why so many human products of creativity have little to no practical value. Sexual selection is an evolutionary force which has the potential to shed new light on this investigation by regarding creativity as a fitness indicator that has evolved for the purposes of courtship and mating. The paper at hand reviews the empirical evidence in support of this hypothesis.

  3. Selectivity and stability of vegetation-applied herbicides in cotton (Gossypium hirsutum L.

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    T. Barakova

    2016-06-01

    Full Text Available Abstract. An experiment was carried out during 2013 – 2015 in the experimental field of the Field Crops Institute, Chirpan, with two cotton cultivars − Helius and Darmi (Gossypium hirsutum L.. Herbicides: Goal 2 E, oxyfluorfen (80 ml/da; Linuron 45 SC, linuron (200 ml/da; Wing-P, pendimethalin + dimethenamid (400 ml/da; Merlin 750 WG, isoxaflutol (5 g/da; Bazagran 480 SL, bentazone (150 ml/da were investigated. They were treated separately or combined with growth regulator Amalgerol (500 ml/da or foliar fertilizer Lactofol O (500 ml/da in the budding stage of the cotton. It was established that selectivity is the lowest in the two cotton cultivars with herbicides Linuron 45 CK and Merlin 750 WG. The purpose of this investigation was to establish the selectivity and stability of some herbicides and their tank mixtures on the cotton by influence of different meteorological conditions. It has been found that the highest phytotoxicity on cotton is given the vegetation-applied herbicides Merlin and Linuron. Foliar fertilizer Laktofol O reduces phytotoxicity of herbicides Goal, Wing, Merlin and Bazagran in two cotton cultivars. Herbicides Wing and Bazagran have excellent selectivity for the two cotton cultivars – Helius and Darmi. The highest yield was obtained by vegetation treatment with herbicide Bazagran, followed by herbicides Wing and Goal. Tank mixtures of Goal, Bazagran and Wing with Laktofol, followed by those with Amalgerol are technologically the most valuable. They combine high yield with high stability over the years. Аlone application of herbicides Linuron and Merlin and their tank mixtures with Amalgerol and Laktofol have low estimate.

  4. Selection of Film Clips and Development of a Video for the Investigation of Sexual Decision Making among Men Who Have Sex with Men

    Science.gov (United States)

    Woolf-King, Sarah E.; Maisto, Stephen; Carey, Michael; Vanable, Peter

    2013-01-01

    Experimental research on sexual decision making is limited, despite the public health importance of such work. We describe formative work conducted in advance of an experimental study designed to evaluate the effects of alcohol intoxication and sexual arousal on risky sexual decision making among men who have sex with men. In Study 1, we describe the procedures for selecting and validating erotic film clips (to be used for the experimental manipulation of arousal). In Study 2, we describe the tailoring of two interactive role-play videos to be used to measure risk perception and communication skills in an analog risky sex situation. Together, these studies illustrate a method for creating experimental stimuli to investigate sexual decision making in a laboratory setting. Research using this approach will support experimental research that affords a stronger basis for drawing causal inferences regarding sexual decision making. PMID:19760530

  5. Warning signal brightness variation: sexual selection may work under the radar of natural selection in populations of a polytypic poison frog.

    Science.gov (United States)

    Crothers, Laura R; Cummings, Molly E

    2013-05-01

    Though theory predicts consistency of warning signals in aposematic species to facilitate predator learning, variation in these signals often occurs in nature. The strawberry poison frog Dendrobates pumilio is an exceptionally polytypic (populations are phenotypically distinct) aposematic frog exhibiting variation in warning color and brightness. In the Solarte population, males and females both respond differentially to male brightness variation. Here, we demonstrate through spectrophotometry and visual modeling that aposematic brightness variation within this population is likely visible to two putative predators (crabs, snakes) and conspecifics but not to the presumed major predator (birds). This study thus suggests that signal brightness within D. pumilio populations can be shaped by sexual selection, with limited opportunity for natural selection to influence this trait due to predator sensory constraints. Because signal brightness changes can ultimately lead to changes in hue, our findings at the within-population level can provide insights into understanding this polytypism at across-population scales.

  6. Stabilization

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    Muhammad H. Al-Malack

    2016-07-01

    Full Text Available Fuel oil flyash (FFA produced in power and water desalination plants firing crude oils in the Kingdom of Saudi Arabia is being disposed in landfills, which increases the burden on the environment, therefore, FFA utilization must be encouraged. In the current research, the effect of adding FFA on the engineering properties of two indigenous soils, namely sand and marl, was investigated. FFA was added at concentrations of 5%, 10% and 15% to both soils with and without the addition of Portland cement. Mixtures of the stabilized soils were thoroughly evaluated using compaction, California Bearing Ratio (CBR, unconfined compressive strength (USC and durability tests. Results of these tests indicated that stabilized sand mixtures could not attain the ACI strength requirements. However, marl was found to satisfy the ACI strength requirement when only 5% of FFA was added together with 5% of cement. When the FFA was increased to 10% and 15%, the mixture’s strength was found to decrease to values below the ACI requirements. Results of the Toxicity Characteristics Leaching Procedure (TCLP, which was performed on samples that passed the ACI requirements, indicated that FFA must be cautiously used in soil stabilization.

  7. Sexually selected sex differences in competitiveness explain sex differences in changes in drinking game participation.

    Science.gov (United States)

    Hone, Liana S E; McCullough, Michael

    2015-05-14

    Drinking games are a risk factor for behavioral and health problems among university students. Previous cross-sectional research by Hone, Carter, and McCullough (2013) replicated well-established sex differences in drinking game behaviors (i.e., that men are more active drinking game participants than are women) and university drinking problems more generally. Hone et al. (2013) also found that these male-specific behavioral patterns are attributable in part to the fact that men's generally unrestricted sexual strategies, plus their social competitiveness, motivate them to participate in drinking games to display their fortitude and compete with same-sex rivals. Here, the authors conducted a study to evaluate with greater causal rigor whether sex differences in sexual restrictedness and social competitiveness-and sex differences in motivations for participating in drinking games in particular-are partially responsible for the sex differences in university students' drinking game behaviors and drinking problems. Sex differences in changes in frequency of drinking game participation were partially mediated by competitive motivations for participating in drinking games and by the effects of social competitiveness on competitive drinking game motivation. These findings lend additional support to the proposition that participation in drinking games is motivated in part by their suitability as a venue for sexual competition in university students' day-to-day lives.

  8. Sexually Selected Sex Differences in Competitiveness Explain Sex Differences in Changes in Drinking Game Participation

    Directory of Open Access Journals (Sweden)

    Liana S. E. Hone

    2015-04-01

    Full Text Available Drinking games are a risk factor for behavioral and health problems among university students. Previous cross-sectional research by Hone, Carter, and McCullough (2013 replicated well-established sex differences in drinking game behaviors (i.e., that men are more active drinking game participants than are women and university drinking problems more generally. Hone et al. (2013 also found that these male-specific behavioral patterns are attributable in part to the fact that men's generally unrestricted sexual strategies, plus their social competitiveness, motivate them to participate in drinking games to display their fortitude and compete with same-sex rivals. Here, the authors conducted a study to evaluate with greater causal rigor whether sex differences in sexual restrictedness and social competitiveness—and sex differences in motivations for participating in drinking games in particular—are partially responsible for the sex differences in university students' drinking game behaviors and drinking problems. Sex differences in changes in frequency of drinking game participation were partially mediated by competitive motivations for participating in drinking games and by the effects of social competitiveness on competitive drinking game motivation. These findings lend additional support to the proposition that participation in drinking games is motivated in part by their suitability as a venue for sexual competition in university students' day-to-day lives.

  9. Selective and reactive hydration of nitriles to amides in water using silver nanoparticles stabilized by organic ligands

    International Nuclear Information System (INIS)

    Kawai, Koji; Kawakami, Hayato; Narushima, Takashi; Yonezawa, Tetsu

    2015-01-01

    Water-dispersible silver nanoparticles stabilized by silver–carbon covalent bonds were prepared. They exhibited high catalytic activities for the selective hydration of nitriles to amides in water. The activation of a nitrile group by the functional groups of the substrates and the hydrophobic layer on the nanoparticles influenced the catalyzed reaction were confirmed. Alkyl nitriles could also be selectively hydrated

  10. Stability of selected volatile breath constituents in Tedlar, Kynar and Flexfilm sampling bags

    Science.gov (United States)

    Mochalski, Paweł; King, Julian; Unterkofler, Karl; Amann, Anton

    2016-01-01

    The stability of 41 selected breath constituents in three types of polymer sampling bags, Tedlar, Kynar, and Flexfilm, was investigated using solid phase microextraction and gas chromatography mass spectrometry. The tested molecular species belong to different chemical classes (hydrocarbons, ketones, aldehydes, aromatics, sulphurs, esters, terpenes, etc.) and exhibit close-to-breath low ppb levels (3–12 ppb) with the exception of isoprene, acetone and acetonitrile (106 ppb, 760 ppb, 42 ppb respectively). Stability tests comprised the background emission of contaminants, recovery from dry samples, recovery from humid samples (RH 80% at 37 °C), influence of the bag’s filling degree, and reusability. Findings yield evidence of the superiority of Tedlar bags over remaining polymers in terms of background emission, species stability (up to 7 days for dry samples), and reusability. Recoveries of species under study suffered from the presence of high amounts of water (losses up to 10%). However, only heavier volatiles, with molecular masses higher than 90, exhibited more pronounced losses (20–40%). The sample size (the degree of bag filling) was found to be one of the most important factors affecting the sample integrity. To sum up, it is recommended to store breath samples in pre-conditioned Tedlar bags up to 6 hours at the maximum possible filling volume. Among the remaining films, Kynar can be considered as an alternative to Tedlar; however, higher losses of compounds should be expected even within the first hours of storage. Due to the high background emission Flexfilm is not suitable for sampling and storage of samples for analyses aiming at volatiles at a low ppb level. PMID:23323261

  11. WIND SPEED AND ATMOSPHERIC STABILITY TRENDS FOR SELECTED UNITED STATES SURFACE STATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Buckley, R; Allen H. Weber, A

    2006-11-01

    Recently it has been suggested that global warming and a decrease in mean wind speeds over most land masses are related. Decreases in near surface wind speeds have been reported by previous investigators looking at records with time spans of 15 to 30 years. This study focuses on United States (US) surface stations that have little or no location change since the late 1940s or the 1950s--a time range of up to 58 years. Data were selected from 62 stations (24 of which had not changed location) and separated into ten groups for analysis. The group's annual averages of temperature, wind speed, and percentage of Pasquill-Gifford (PG) stability categories were fitted with linear least squares regression lines. The results showed that the temperatures have increased for eight of the ten groups as expected. Wind speeds have decreased for nine of the ten groups. The mean slope of the wind speed trend lines for stations within the coterminous US was -0.77 m s{sup -1} per century. The percentage frequency of occurrence for the neutral (D) PG stability category decreased, while that for the unstable (B) and the stable (F) categories increased in almost all cases except for the group of stations located in Alaska.

  12. How cuckoldry can decrease the opportunity for sexual selection: Data and theory from a genetic parentage analysis of the sand goby, Pomatoschistus minutus

    Science.gov (United States)

    Jones, Adam G.; Walker, DeEtte; Kvarnemo, Charlotta; Lindström, Kai; Avise, John C.

    2001-01-01

    Alternative mating strategies are common in nature and are generally thought to increase the intensity of sexual selection. However, cuckoldry can theoretically decrease the opportunity for sexual selection, particularly in highly polygamous species. We address here the influence of sneaking (fertilization thievery) on the opportunity for sexual selection in the sand goby Pomatoschistus minutus, a marine fish species in which males build and defend nests. Our microsatellite-based analysis of the mating system in a natural sand goby population shows high rates of sneaking and multiple mating by males. Sneaker males had fertilized eggs in ≈50% of the assayed nests, and multiple sneakers sometimes fertilized eggs from a single female. Successful males had received eggs from 2 to 6 females per nest (mean = 3.4). We developed a simple mathematical model showing that sneaking in this polygynous sand goby population almost certainly decreases the opportunity for sexual selection, an outcome that contrasts with the usual effects of cuckoldry in socially monogamous animals. These results highlight a more complex and interesting relationship between cuckoldry rates and the intensity of sexual selection than previously assumed in much of the literature on animal mating systems. PMID:11481481

  13. Evolutionary dynamics on networks of selectively neutral genotypes: effects of topology and sequence stability.

    Science.gov (United States)

    Aguirre, Jacobo; Buldú, Javier M; Manrubia, Susanna C

    2009-12-01

    Networks of selectively neutral genotypes underlie the evolution of populations of replicators in constant environments. Previous theoretical analysis predicted that such populations will evolve toward highly connected regions of the genome space. We first study the evolution of populations of replicators on simple networks and quantify how the transient time to equilibrium depends on the initial distribution of sequences on the neutral network, on the topological properties of the latter, and on the mutation rate. Second, network neutrality is broken through the introduction of an energy for each sequence. This allows to study the competition between two features (neutrality and energetic stability) relevant for survival and subjected to different selective pressures. In cases where the two features are negatively correlated, the population experiences sudden migrations in the genome space for values of the relevant parameters that we calculate. The numerical study of larger networks indicates that the qualitative behavior to be expected in more realistic cases is already seen in representative examples of small networks.

  14. Evolutionary dynamics on networks of selectively neutral genotypes: Effects of topology and sequence stability

    Science.gov (United States)

    Aguirre, Jacobo; Buldú, Javier M.; Manrubia, Susanna C.

    2009-12-01

    Networks of selectively neutral genotypes underlie the evolution of populations of replicators in constant environments. Previous theoretical analysis predicted that such populations will evolve toward highly connected regions of the genome space. We first study the evolution of populations of replicators on simple networks and quantify how the transient time to equilibrium depends on the initial distribution of sequences on the neutral network, on the topological properties of the latter, and on the mutation rate. Second, network neutrality is broken through the introduction of an energy for each sequence. This allows to study the competition between two features (neutrality and energetic stability) relevant for survival and subjected to different selective pressures. In cases where the two features are negatively correlated, the population experiences sudden migrations in the genome space for values of the relevant parameters that we calculate. The numerical study of larger networks indicates that the qualitative behavior to be expected in more realistic cases is already seen in representative examples of small networks.

  15. Sexual orientation and spatial position effects on selective forms of object location memory.

    Science.gov (United States)

    Rahman, Qazi; Newland, Cherie; Smyth, Beatrice Mary

    2011-04-01

    Prior research has demonstrated robust sex and sexual orientation-related differences in object location memory in humans. Here we show that this sexual variation may depend on the spatial position of target objects and the task-specific nature of the spatial array. We tested the recovery of object locations in three object arrays (object exchanges, object shifts, and novel objects) relative to veridical center (left compared to right side of the arrays) in a sample of 35 heterosexual men, 35 heterosexual women, and 35 homosexual men. Relative to heterosexual men, heterosexual women showed better location recovery in the right side of the array during object exchanges and homosexual men performed better in the right side during novel objects. However, the difference between heterosexual and homosexual men disappeared after controlling for IQ. Heterosexual women and homosexual men did not differ significantly from each other in location change detection with respect to task or side of array. These data suggest that visual space biases in processing categorical spatial positions may enhance aspects of object location memory in heterosexual women. Copyright © 2010 Elsevier Inc. All rights reserved.

  16. Selection for chlorpyrifos resistance in Liriomyza sativae Blanchard: Cross-resistance patterns, stability and biochemical mechanisms.

    Science.gov (United States)

    Askari-Saryazdi, Ghasem; Hejazi, Mir Jalil; Ferguson, J Scott; Rashidi, Mohammad-Reza

    2015-10-01

    The vegetable leafminer (VLM), Liriomyza sativae (Diptera: Agromyzidae) is a serious pest of vegetable crops and ornamentals worldwide. In cropping systems with inappropriate management strategies, development of resistance to insecticides in leafminers is probable. Chlorpyrifos is a commonly used pesticide for controlling leafminers in Iran, but resistance to this insecticide in leafminers has not been characterized. In order to develop strategies to minimize resistance in the field and greenhouse, a laboratory selected chlorpyrifos resistant strain of L. sativae was used to characterize resistance and determine the rate of development and stability of resistance. Selecting for resistance in the laboratory after 23 generations yielded a chlorpyrifos resistant selected strain (CRSS) with a resistance ratio of 40.34, determined on the larval stage. CRSS exhibited no cross-resistance to other tested insecticides except for diazinon. Synergism and biochemical assays indicated that esterases (EST) had a key role in metabolic resistance to chlorpyrifos, but glutathione S-transferase (GST) and mixed function oxidase (MFO) were not mediators in this resistance. In CRSS acetylcholinesterase (AChE) was more active than the susceptible strain, Sharif (SH). AChE in CRSS was also less sensitive to inhibition by propoxur. The kinetics parameters (Km and Vmax) of AChE indicated that affinities and hydrolyzing efficiencies of this enzyme in CRSS were higher than SH. Susceptibility to chlorpyrifos in L. sativae was re-gained in the absence of insecticide pressure. Synergism, biochemical and cross-resistance assays revealed that overactivity of metabolic enzymes and reduction in target site sensitivity are probably joint factors in chlorpyrifos resistance. An effective insecticide resistance management program is necessary to prevent fast resistance development in crop systems. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. The effects of stabilizing and directional selection on phenotypic and genotypic variation in a population of RNA enzymes.

    Science.gov (United States)

    Hayden, Eric J; Bratulic, Sinisa; Koenig, Iwo; Ferrada, Evandro; Wagner, Andreas

    2014-02-01

    The distribution of variation in a quantitative trait and its underlying distribution of genotypic diversity can both be shaped by stabilizing and directional selection. Understanding either distribution is important, because it determines a population's response to natural selection. Unfortunately, existing theory makes conflicting predictions about how selection shapes these distributions, and very little pertinent experimental evidence exists. Here we study a simple genetic system, an evolving RNA enzyme (ribozyme) in which a combination of high throughput genotyping and measurement of a biochemical phenotype allow us to address this question. We show that directional selection, compared to stabilizing selection, increases the genotypic diversity of an evolving ribozyme population. In contrast, it leaves the variance in the phenotypic trait unchanged.

  18. Stability of live attenuated rotavirus vaccine with selected preservatives and primary containers.

    Science.gov (United States)

    Lal, Manjari; Jarrahian, Courtney; Zhu, Changcheng; Hosken, Nancy A; McClurkan, Chris L; Koelle, David M; Saxon, Eugene; Roehrig, Andrew; Zehrung, Darin; Chen, Dexiang

    2016-05-11

    that was similar to its profile in standard glass vials. This study demonstrates that there are multiple options for the primary container for rotavirus vaccines intended for oral delivery. Selection of an optimal primary container should take into consideration additional factors, including stability as well as cold chain volume, usability, cost, and manufacturing feasibility. Copyright © 2016. Published by Elsevier Ltd.

  19. Selection on male size, leg length and condition during mate search in a sexually highly dimorphic orb-weaving spider.

    Science.gov (United States)

    Foellmer, Matthias W; Fairbairn, Daphne J

    2005-02-01

    Mate search plays a central role in hypotheses for the adaptive significance of extreme female-biased sexual size dimorphism (SSD) in animals. Spiders (Araneae) are the only free-living terrestrial taxon where extreme SSD is common. The "gravity hypothesis" states that small body size in males is favoured during mate search in species where males have to climb to reach females, because body length is inversely proportional to achievable speed on vertical structures. However, locomotive performance of males may also depend on relative leg length. Here we examine selection on male body size and leg length during mate search in the highly dimorphic orb-weaving spider Argiope aurantia, using a multivariate approach to distinguish selection targeted at different components of size. Further, we investigate the scaling relationships between male size and energy reserves, and the differential loss of reserves. Adult males do not feed while roving, and a size-dependent differential energy storage capacity may thus affect male performance during mate search. Contrary to predictions, large body size was favoured in one of two populations, and this was due to selection for longer legs. Male size was not under selection in the second population, but we detected direct selection for longer third legs. Males lost energy reserves during mate search, but this was independent of male size and storage capacity scaled isometrically with size. Thus, mate search is unlikely to lead to selection for small male size, but the hypothesis that relatively longer legs in male spiders reflect a search-adapted morphology is supported.

  20. Heightened condition-dependent growth of sexually selected weapons in the rhinoceros beetle, Trypoxylus dichotomus (Coleoptera: Scarabaeidae).

    Science.gov (United States)

    Johns, A; Gotoh, H; McCullough, E L; Emlen, D J; Lavine, L C

    2014-10-01

    The exaggerated weapons and ornaments of sexual selection are condition-dependent traits that often grow to exaggerated proportions. The horns of male rhinoceros beetles are extremely sensitive to the larval nutritional environment and are used by rival males in combat over access to females. In contrast to horns, other parts of the body, such as wings, eyes, and legs, scale proportionally with body size, whereas others, such as males' external genitalia, are invariant with body size, regardless of nutrition. We document how body parts of the Asian rhinoceros beetle, Trypoxylus dichotomus, exhibit plasticity and constraint in response to nutritional condition. We discuss the implications of these results for the evolution of condition-dependent and condition-independent traits in animals. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

  1. An expressed sequence tag (EST) library for Drosophila serrata, a model system for sexual selection and climatic adaptation studies.

    Science.gov (United States)

    Frentiu, Francesca D; Adamski, Marcin; McGraw, Elizabeth A; Blows, Mark W; Chenoweth, Stephen F

    2009-01-21

    The native Australian fly Drosophila serrata belongs to the highly speciose montium subgroup of the melanogaster species group. It has recently emerged as an excellent model system with which to address a number of important questions, including the evolution of traits under sexual selection and traits involved in climatic adaptation along latitudinal gradients. Understanding the molecular genetic basis of such traits has been limited by a lack of genomic resources for this species. Here, we present the first expressed sequence tag (EST) collection for D. serrata that will enable the identification of genes underlying sexually-selected phenotypes and physiological responses to environmental change and may help resolve controversial phylogenetic relationships within the montium subgroup. A normalized cDNA library was constructed from whole fly bodies at several developmental stages, including larvae and adults. Assembly of 11,616 clones sequenced from the 3' end allowed us to identify 6,607 unique contigs, of which at least 90% encoded peptides. Partial transcripts were discovered from a variety of genes of evolutionary interest by BLASTing contigs against the 12 Drosophila genomes currently sequenced. By incorporating into the cDNA library multiple individuals from populations spanning a large portion of the geographical range of D. serrata, we were able to identify 11,057 putative single nucleotide polymorphisms (SNPs), with 278 different contigs having at least one "double hit" SNP that is highly likely to be a real polymorphism. At least 394 EST-associated microsatellite markers, representing 355 different contigs, were also found, providing an additional set of genetic markers. The assembled EST library is available online at http://www.chenowethlab.org/serrata/index.cgi. We have provided the first gene collection and largest set of polymorphic genetic markers, to date, for the fly D. serrata. The EST collection will provide much needed genomic resources for

  2. Substantially Stabilized Superacid Incorporated SBA-15 with Calcium Bridging for Selective Esterification of Glycerol

    Science.gov (United States)

    Hoo, P. Y.; Abdullah, A. Z.; Shuit, S. H.; Teoh, Y. P.; Ng, Q. H.; Kunasundari, B.

    2018-03-01

    The exploitation of the super acidity of heteropolyacids incorporated heterogeneous catalysts was only feasible if the heterogeneity of these catalysts was assured. To maintain the catalyst heterogeneity in polar medium, a novel two-step modification method was proposed to synthesize the highly active, yet stable heterogeneous catalyst, catered for selective esterification of monoglyceride. The surficial, structural and acidity properties of the modified catalysts were investigated via crucial characterization methods (N2 BET, HRTEM, and FTIR). The collective evidences verified the predicted formation of calcium oxides (CaO) on the mesopores surfaces of the SBA-15 support after the first modification, and the successful subsequent 12-tungstophosphoric acid (HPW) functionalization. The superior stability of the synthesized catalysts (10wt%-HPW/CaSBA-15) was demonstrated (negligible change in both conversion – 75% and yield – 70%), without the need for catalyst regeneration. Such result was attributed to the strong interaction between HPW and SBA-15 via calcium bridging. Being alkaline in nature, calcium oxides in the inner pores readily reacted with highly acidic HPW introduced in the subsequent wetness incipient step, forming insoluble HPW acid sites on inner pore walls of SBA-15 via the calcium bridging. This modification deemed promising and other alkaline metals should be explored in the future.

  3. A lover or a fighter? Opposing sexual selection pressures on men’s vocal pitch and facial hair

    Science.gov (United States)

    Mackey, Lauren L.; McCarty, Kristofor; Neave, Nick

    2016-01-01

    The traditional assumption within the research literature on human sexually dimorphic traits has been that many sex differences have arisen from intersexual selection. More recently, however, there has been a shift toward the idea that many male features, including male lower-pitched voices and male beard growth, might have arisen predominantly through intrasexual selection: that is, to serve the purpose of male–male competition instead of mate attraction. In this study, using a unique set of video stimuli, we measured people’s perceptions of the dominance and attractiveness of men who differ both in terms of voice pitch (4 levels from lower to higher pitched) and beard growth (4 levels from clean shaven to a month’s hair growth). We found a nonlinear relationship between lower pitch and increased attractiveness; men’s vocal attractiveness peaked at around 96 Hz. Beard growth had equivocal effects on attractiveness judgments. In contrast, perceptions of men’s dominance simply increased with increasing masculinity (i.e., with lower-pitched voices and greater beard growth). Together, these results suggest that the optimal level of physical masculinity might differ depending on whether the outcome is social dominance or mate attraction. These dual selection pressures might maintain some of the documented variability in male physical and behavioral masculinity that we see today. PMID:27004013

  4. Quantitative measures of sexual selection reveal no evidence for sex-role reversal in a sea spider with prolonged paternal care.

    Science.gov (United States)

    Barreto, Felipe S; Avise, John C

    2010-10-07

    Taxa in which males alone invest in postzygotic care of offspring are often considered good models for investigating the proffered relationships between sexual selection and mating systems. In the pycnogonid sea spider Pycnogonum stearnsi, males carry large egg masses on their bodies for several weeks, so this species is a plausible candidate for sex-role reversal (greater intensity of sexual selection on females than on males). Here, we couple a microsatellite-based assessment of the mating system in a natural population with formal quantitative measures of genetic fitness to investigate the direction of sexual selection in P. stearnsi. Both sexes proved to be highly polygamous and showed similar standardized variances in reproductive and mating successes. Moreover, the fertility (number of progeny) of males and females appeared to be equally and highly dependent on mate access, as shown by similar Bateman gradients for the two sexes. The absence of sex-role reversal in this population of P. stearnsi is probably attributable to the fact that males are not limited by brooding space but have evolved an ability to carry large numbers of progeny. Body length was not a good predictor of male mating or reproductive success, so the aim of future studies should be to determine what traits are the targets of sexual selection in this species.

  5. "I Don't Shag Dirty Girls": Marginalized Masculinities and the Use of Partner Selection as a Sexual Health Risk Reduction Strategy in Heterosexual Young Men.

    Science.gov (United States)

    Limmer, Mark

    2016-03-01

    Understanding and addressing the sexual risk taking of young men remains a key research, policy, and practice concern in attempts to improve the emotional and physical sexual health of young men and their sexual partners. This article explores one of the ways in which young men attempt to mitigate sexual risk through the assigning of labels to particular young women and using these as a basis for their decisions in relation to sexual activity, contraception, and condom use. The article uses the lens of hegemonic masculinities theory to increase understanding of the role played by the construction and performance of marginalized masculinities and how these in turn are influenced by social exclusionary processes. The article draws on focus group and interview data from 46 young men aged 15 to 17 years living in the northwest of England, purposively selected on the basis of the prevailing policy definitions of social inclusion and exclusion. The article describes a form of marginalized masculinity pertaining to socially excluded young men, which as a result of limited access to other tenets of hegemonic masculinity, is disproportionately reliant on sexual expertise and voracity alongside overt demonstrations of their superiority over women. It is in this context that young women are assigned the labels of "dirty" or "clean" on the basis of a selection of arbitrary judgments relating to dress, demeanor, area of residence, and perceived sexual activities. The motivations of the young men, the impact on young women, and the policy and practice implications are all discussed. © The Author(s) 2014.

  6. Genomic association for sexual precocity in beef heifers using pre-selection of genes and haplotype reconstruction.

    Directory of Open Access Journals (Sweden)

    Luciana Takada

    Full Text Available Reproductive traits are of the utmost importance for any livestock farming, but are difficult to measure and to interpret since they are influenced by various factors. The objective of this study was to detect associations between known polymorphisms in candidate genes related to sexual precocity in Nellore heifers, which could be used in breeding programs. Records of 1,689 precocious and non-precocious heifers from farms participating in the Conexão Delta G breeding program were analyzed. A subset of single nucleotide polymorphisms (SNP located in the region of the candidate genes at a distance of up to 5 kb from the boundaries of each gene, were selected from the panel of 777,000 SNPs of the High-Density Bovine SNP BeadChip. Linear mixed models were used for statistical analysis of early heifer pregnancy, relating the trait with isolated SNPs or with haplotype groups. The model included the contemporary group (year and month of birth as fixed effect and parent of the animal (sire effect as random effect. The fastPHASE® and GenomeStudio® were used for reconstruction of the haplotypes and for analysis of linkage disequilibrium based on r2 statistics. A total of 125 candidate genes and 2,024 SNPs forming haplotypes were analyzed. Statistical analysis after Bonferroni correction showed that nine haplotypes exerted a significant effect (p<0.05 on sexual precocity. Four of these haplotypes were located in the Pregnancy-associated plasma protein-A2 gene (PAPP-A2, two in the Estrogen-related receptor gamma gene (ESRRG, and one each in the Pregnancy-associated plasma protein-A gene (PAPP-A, Kell blood group complex subunit-related family (XKR4 and mannose-binding lectin genes (MBL-1 genes. Although the present results indicate that the PAPP-A2, PAPP-A, XKR4, MBL-1 and ESRRG genes influence sexual precocity in Nellore heifers, further studies are needed to evaluate their possible use in breeding programs.

  7. Insights into population ecology and sexual selection in snakes through the application of DNA-based genetic markers.

    Science.gov (United States)

    Gibbs, H L; Weatherhead, P J

    2001-01-01

    Hypervariable genetic markers have revolutionized studies of kinship, behavioral ecology, and population biology in vertebrate groups such as birds, but their use in snakes remains limited. To illustrate the value of such markers in snakes, we review studies that have used microsatellite DNA loci to analyze local population differentiation and parentage in snakes. Four ecologically distinct species of snakes all show evidence for differentiation at small spatial scales (2-15 km), but with substantial differences among species. This result highlights how genetic analysis can reveal hidden aspects of the natural history of difficult-to-observe taxa, and it raises important questions about the ecological factors that may contribute to restricted gene flow. A 3-year study of genetic parentage in marked populations of the northern water snake showed that (1) participation in mating aggregations was a poor predictor of genetic-based measures of reproductive success; (2) multiple paternity was high, yet there was no detectable fitness advantage to multiple mating by females; and (3) the opportunity for selection was far higher in males than in females due to a larger variance in male reproductive success, and yet this resulted in no detectable selection on morphological variation in males. Thus genetic markers have provided accurate measures of individual reproductive success in this species, an important step toward resolving the adaptive significance of key features including multiple paternity and reversed sexual size dimorphism. Overall these studies illustrate how genetic analyses of snakes provide previously unobtainable information of long-standing interest to behavioral ecologists.

  8. Impact of a Supportive Housing Program on Housing Stability and Sexually Transmitted Infections Among Young Adults in New York City Who Were Aging Out of Foster Care.

    Science.gov (United States)

    Lim, Sungwoo; Singh, Tejinder P; Gwynn, R Charon

    2017-08-01

    Former foster youth are at increased risk of housing instability and sexually transmitted infections (STIs) during the transitional period following foster care. We measured housing stability using sequence analysis and assessed whether a supportive housing program in New York, New York, was effective in improving housing stability and reducing STIs among former foster youth. Matched administrative records identified 895 former foster youth who were eligible for the housing program during 2007-2010. The main outcomes included housing stability (as determined from episodes of homelessness, incarceration, hospitalization, and residence in supportive housing) and diagnosed STI case rates per 1,000 person-years during the 2 years after baseline. Marginal structural models were used to assess impacts of the program on these outcomes. Three housing stability patterns (unstable housing, stable housing, and rare institutional dwelling patterns) were identified. The housing program was positively associated with a pattern of stable housing (odds ratio = 4.4, 95% confidence interval: 2.9, 6.8), and negatively associated with diagnosed STI rates (relative risk = 0.3, 95% confidence interval: 0.2, 0.7). These positive impacts on housing stability and STIs highlight the importance of the supportive housing program for youths aging out of foster care and the need for such programs to continue. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. A selective androgen receptor modulator with minimal prostate hypertrophic activity enhances lean body mass in male rats and stimulates sexual behavior in female rats.

    Science.gov (United States)

    Allan, George F; Tannenbaum, Pamela; Sbriscia, Tifanie; Linton, Olivia; Lai, Muh-Tsann; Haynes-Johnson, Donna; Bhattacharjee, Sheela; Zhang, Xuqing; Sui, Zhihua; Lundeen, Scott G

    2007-08-01

    Androgen receptor (AR) ligands with tissue selectivity (selective androgen receptor modulators, or SARMs) have potential for treating muscle wasting, hypogonadism of aging, osteoporosis, female sexual dysfunction, and other indications. JNJ-28330835 is a nonsteroidal AR ligand with mixed agonist and antagonist activity in androgen-responsive cell-based assays. It is an orally active SARM with muscle selectivity in orchidectomized rat models. It stimulated growth of the levator ani muscle, stimulating maximal growth at a dose of 10 mg/kg. At the same time, JNJ-28330835 reduced prostate weight in intact rats by a mean of 30% at 10 mg/kg, while having no inhibitory effect on muscle. Using magnetic resonance imaging (MRI) to monitor body composition, it prevented half of the loss of lean body mass associated with orchidectomy, and restored about 30% of lost lean mass to aged orchidectomized rats. It had agonist effects on markers of both osteoclast and osteoblast activity, suggesting that it reduces bone turnover. In a model of sexual behavior, JNJ-28330835 enhanced the preference of ovariectomized female rats for sexually intact male rats over nonsexual orchidectomized males. JNJ-28330835 is a prostate-sparing SARM with the potential for clinically beneficial effects in muscle-wasting diseases and sexual function disorders.

  10. Estimation AMMI stability value as a measure for selection two row barley mutants

    International Nuclear Information System (INIS)

    Azzo, F. Z.

    2012-12-01

    A field experiment was carried out at the Tuwaitha research station (the Iraqi Atomic Energy Commission / Ministry of Science and Technology now) to estimate AMMI stability value of 18 mutants two row cultivate over three genetic generations (environments). The results showed that two mutants 91 and 25 was superiority in grain yield character (kg / ha) and the original 4/5 mutations are more stable and this is a good sign about the possibility of using AMMI stability value in estimating stability in the late generations. (Author)

  11. Untold stories: biases and selection effects in research with victims of trafficking for sexual exploitation.

    Science.gov (United States)

    Brunovskis, Anette; Surtees, Rebecca

    2010-01-01

    Recent discussions of trafficking research have included calls for more innovative studies and new methodologies in order to move beyond the current trafficking narrative, which is often based on unrepresentative samples and overly simplified images. While new methods can potentially play a role in expanding the knowledge base on trafficking, this article argues that the solution is not entirely about applying new methods, but as much about using current methods to greater effect and with careful attention to their limitations and ethical constraints. Drawing on the authors' experience in researching trafficking issues in a number of projects over the past decade, the article outlines and exemplifies some of the methodological and ethical issues to be considered and accommodated when conducting research with trafficked persons -- including unrepresentative samples; access to respondents; selection biases by "gatekeepers" and self selection by potential respondents. Such considerations should inform not only how research is undertaken but also how this information is read and understood. Moreover, many of these considerations equally apply when considering the application of new methods within this field. The article maintains that a better understanding of how these issues come into play and inform trafficking research will translate into tools for conducting improved research in this field and, by implication, new perspectives on human trafficking.

  12. Stability and selectivity of a chronic, multi-contact cuff electrode for sensory stimulation in human amputees.

    Science.gov (United States)

    Tan, Daniel W; Schiefer, Matthew A; Keith, Michael W; Anderson, J Robert; Tyler, Dustin J

    2015-04-01

    Stability and selectivity are important when restoring long-term, functional sensory feedback in individuals with limb-loss. Our objective is to demonstrate a chronic, clinical neural stimulation system for providing selective sensory response in two upper-limb amputees. Multi-contact cuff electrodes were implanted in the median, ulnar, and radial nerves of the upper-limb. Nerve stimulation produced a selective sensory response on 19 of 20 contacts and 16 of 16 contacts in subjects 1 and 2, respectively. Stimulation elicited multiple, distinct percept areas on the phantom and residual limb. Consistent threshold, impedance, and percept areas have demonstrated that the neural interface is stable for the duration of this on-going, chronic study. We have achieved selective nerve response from multi-contact cuff electrodes by demonstrating characteristic percept areas and thresholds for each contact. Selective sensory response remains consistent in two upper-limb amputees for 1 and 2 years, the longest multi-contact sensory feedback system to date. Our approach demonstrates selectivity and stability can be achieved through an extraneural interface, which can provide sensory feedback to amputees.

  13. Experimental analysis of multivariate female choice in gray treefrogs (Hyla versicolor): evidence for directional and stabilizing selection.

    Science.gov (United States)

    Gerhardt, H Carl; Brooks, Robert

    2009-10-01

    Even simple biological signals vary in several measurable dimensions. Understanding their evolution requires, therefore, a multivariate understanding of selection, including how different properties interact to determine the effectiveness of the signal. We combined experimental manipulation with multivariate selection analysis to assess female mate choice on the simple trilled calls of male gray treefrogs. We independently and randomly varied five behaviorally relevant acoustic properties in 154 synthetic calls. We compared response times of each of 154 females to one of these calls with its response to a standard call that had mean values of the five properties. We found directional and quadratic selection on two properties indicative of the amount of signaling, pulse number, and call rate. Canonical rotation of the fitness surface showed that these properties, along with pulse rate, contributed heavily to a major axis of stabilizing selection, a result consistent with univariate studies showing diminishing effects of increasing pulse number well beyond the mean. Spectral properties contributed to a second major axis of stabilizing selection. The single major axis of disruptive selection suggested that a combination of two temporal and two spectral properties with values differing from the mean should be especially attractive.

  14. Sweetpotato breeding for northeastern Uganda: farmer varieties, farmer-participatory selection, and stability of performance

    NARCIS (Netherlands)

    Abidin, P.E.

    2004-01-01

    Keywords: Agro-biodiversity, farmer varieties, indigenous knowledge, farmer-participatory research, genetic diversity, genotype-by-environment interaction, germplasm collection, Ipomoea batatas , specific adaptation, yield stability, sweetpotato, variance component

  15. Qualitative evaluation of selected social factors that impact sexual risk-taking behaviour among African students in Kwazulu-Natal, South Africa.

    Science.gov (United States)

    Ngidi, Ndumiso Daluxolo; Moyo, Sibusiso; Zulu, Thobile; Adam, Jamila Khatoon; Krishna, Suresh Babu Naidu

    2016-12-01

    The incidence of HIV and AIDS continues to be a source of great concern within universities in South Africa. Furthermore, university students constitute an important community in the intervention against the HIV/AIDS epidemic. Students in the age group of 15-24 years are at a greater risk of HIV infection than any other group in the country; yet, little is known about why they continue to engage in risky sexual practices. This study was designed to explore the sexual behaviour of students in a metropolitan Durban University of Technology in KwaZulu-Natal to understand the social factors underlying their risk of HIV infection. This is a qualitative study that used cluster sampling where the population was stratified by campus and faculty. The study population was selected using a standard randomization technique. This was a part of a multi-phased research project aimed at providing a sero-prevalence baseline and an analysis of risk-taking behaviour at a Durban University of Technology in the eThekwini Metropolitan Municipality area. The study highlights peer pressure among students as an influence in promoting high-risk sexual behaviour. Within this context, the findings revealed that university students lack the ability to negotiate risk-aware decisions especially regarding sexual relationships. This study draws attention to the perspectives of African university students regarding their risk-taking sexual practices and selected factors which influence such behaviour. The findings are not exhaustive in exploring contextual antecedents that shape students' sexual practices. However, they provide an important basis in understanding key factors which expose students to HIV infections. The study provides insights into opportunities for further studies as well as preventative implications.

  16. Directed surfaces structures and interfaces for enhanced electrocatalyst activity, selectivity, and stability for energy conversion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Jaramillo, Thomas F. [Stanford Univ., CA (United States). Dept. of Chemical Engineering. Shriram Center

    2016-04-20

    In this project, we have employed a systematic approach to develop active, selective, and stable catalyst materials for important electrochemical reactions involving energy conversion. In particular, we have focused our attention on developing active catalyst materials for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). HER: We have synthesized and investigated several highly active and acid stable non-precious metal HER catalysts, including: [Mo3S13]2- nanoclusters (Nature Chemistry, 2014) and molybdenum phosphosulfide (MoP|S) (Angewandte Chemie, 2014). We have also aimed to engineer these catalyst formulations in a membrane electrode assembly (MEA) for fundamental studies of water electrolysis at high current densities, approximately 1 A/cm2 (ChemSusChem, 2015). We furthermore investigated transition metal phosphide (TMP) catalysts for HER by a combined experimental–theoretical approach (Energy & Environmental Science, 2015). By synthesizing different TMPs and comparing experimentally determined HER activities with the hydrogen adsorption free energies, ΔGH, calculated by density functional theory, we showed that the TMPs follow a volcano relationship for the HER. Using our combined experimental–theoretical model, we predicted that the mixed metal TMP, Fe0.5Co0.5P, should have a near-optimal ΔGH. We synthesized several mixtures of Co and Fe phosphides alloys and confirmed that Fe0.5Co0.5P exhibits the highest HER activity of the investigated TMPs (Energy & Environmental Science, 2015). The understanding gained as to how to improve catalytic activity for the HER, particularly for non-precious metal materials, is important to DOE targets for sustainable H2 production. OER: We have developed a SrIrO3/IrOx catalyst for acidic conditions (submitted, 2016). The Sr

  17. HIV and selected blood-borne and sexually transmitted infections in a predominantly Roma (Gypsy) neighbourhood in Budapest, Hungary

    Science.gov (United States)

    Gyarmathy, V. Anna; Ujhelyi, Eszter; Neaigus, Alan

    2008-01-01

    We assessed the prevalence of HIV and selected blood-borne and sexually transmitted infections among a convenience sample of 64 residents of Dzsumbuj, a predominantly Roma (Gypsy) neighbourhood in Budapest, Hungary. No cases of HIV were detected, while the prevalence of Hepatitis B infection (anti-HBc) was 27% and syphilis prevalence was 2%. Romas (n=50) were significantly more likely than non-Romas (n=14) to have HAV antibodies (80% vs. 43%) and less likely to be HBV immunized (anti-HBs only; 6% vs. 29%). Current drug injectors (n=13) were more likely than non-injectors (n=51) to have antibodies against HAV (85% vs. 69%) and HCV (85% vs. 8%). While HIV has not been introduced in this population, risk conditions for a potentially explosive HIV epidemic are present. Health care policies should focus on expanding coverage for HAV and HBV immunizations, and access to HIV preventive services needs to be extended to marginalized, mostly minority populations, such as the Roma in Europe. PMID:18935777

  18. The effect of normative feedback on stability and efficacy of some selected muscles in a balancing task

    Directory of Open Access Journals (Sweden)

    Saeed Ashrafpoor Navaee

    2016-03-01

    Full Text Available The purpose of the present study was to determine the effects of normative feedback on stability and efficacy of some selected muscles at different task difficulty levels in novice individuals. Thirty participants (age Mean= 22.60, SD=1.89 years were randomly assigned into three groups of positive, negative normative feedback and control.  The experimental groups participated in 160 acquisition trials (16 blocks of 10trials for 4 consecutive days (40 per day. Post test was performed after last practice session. The result of ANOVA-repeated measure test indicated that positive normative feedback group outperformed the other groups in stability indices of overall stability (P=0.004, anterior-posterior (P=0.01 and medial-lateral (P=0.001. In addition, the result of Covariance test at electromyography indices of the Soleus and Peroneus brevis showed significant differences in the favor of positive normative feedback in post-test. The findings of the present study showed that normative feedback has functional motivation affect that directly influences physiological changes level of stability control. KEY WORDS: Electromyography, knowledge of result, normative feedback, performance, stability control.

  19. A possible case of contemporary selection leading to a decrease in sexual plumage dimorphism in a grassland-breeding shorebird

    NARCIS (Netherlands)

    Schroeder, Julia; Lourenco, Pedro M.; Hooijmeijer, Jos C.E.W.; Both, Christiaan; Piersma, Theunis

    2009-01-01

    In sexually dimorphic species, males with more exaggerated plumage ornamentation generally have higher body condition, are preferred by females, and have higher reproductive output. In contrast to the majority of studies, we describe that less ornamented males of the monogamous and sexually

  20. Human's cognitive ability to assess facial cues from photographs: a study of sexual selection in the Bolivian Amazon.

    Directory of Open Access Journals (Sweden)

    Eduardo A Undurraga

    Full Text Available BACKGROUND: Evolutionary theory suggests that natural selection favors the evolution of cognitive abilities which allow humans to use facial cues to assess traits of others. The use of facial and somatic cues by humans has been studied mainly in western industrialized countries, leaving unanswered whether results are valid across cultures. METHODOLOGY/PRINCIPAL FINDINGS: Our objectives were to test (i if previous finding about raters' ability to get accurate information about an individual by looking at his facial photograph held in low-income non western rural societies and (ii whether women and men differ in this ability. To answer the questions we did a study during July-August 2007 among the Tsimane', a native Amazonian society of foragers-farmers in Bolivia. We asked 40 females and 40 males 16-25 years of age to rate four traits in 93 facial photographs of other Tsimane' males. The four traits were based on sexual selection theory, and included health, dominance, knowledge, and sociability. The rating scale for each trait ranged from one (least to four (most. The average rating for each trait was calculated for each individual in the photograph and regressed against objective measures of the trait from the person in the photograph. We found that (i female Tsimane' raters were able to assess facial cues related to health, dominance, and knowledge and (ii male Tsimane' raters were able to assess facial cues related to dominance, knowledge, and sociability. CONCLUSIONS/SIGNIFICANCE: Our results support the existence of a human ability to identify objective traits from facial cues, as suggested by evolutionary theory.

  1. Stability constant determinations for technetium (IV) complexation with selected amino carboxylate ligands in high nitrate solutions

    Energy Technology Data Exchange (ETDEWEB)

    Omoto, Trevor; Wall, Nathalie A. [Washington State Univ., Pullman, WA (United States). Dept. of Chemistry

    2017-10-01

    The stability constants for Tc(IV) complexation with the ligands IDA, NTA, HEDTA, and DTPA were determined in varied nitrate concentrations using liquid-liquid extraction methods. The determined log β{sub 101} stability constants at 0.5 M NaNO{sub 3} were found to be 9.2±0.3, 10.3±0.3, and 15.3±0.3 for IDA, NTA, and HEDTA, respectively. The log β{sub 111} stability constant for DTPA was determined to be 22.0±0.6. These determined stability constants show a slight decrease in magnitude as a function of increasing NaNO{sub 3} concentration. These stability constants were used to model the total dissolution of Tc(IV) in acidic aqueous solutions in the presence of each ligand. The results of these predictive models indicate that amino carboxylic ligands have a high potential for increasing the aqueous dissolution of Tc(IV); at pH 2.3, 0.01 M ligand yield dissolved Tc(IV) concentrations of 1.42.10{sup -5} M, 1.33.10{sup -5} M, 6.07.10{sup -6} M, 9.65.10{sup -7} M, for DTPA, HEDTA, NTA, and IDA, respectively.

  2. Factors Contributing to Sexual Violence at Selected Schools for Learners with Mild Intellectual Disability in South Africa.

    Science.gov (United States)

    Nyokangi, Doris; Phasha, Nareadi

    2016-05-01

    This paper reports part of the findings of a study which exposed sexual violence in schools for learners with mild intellectual disability in South Africa. Special attention was paid on factors contributing to such a problem. Data were collected using focus groups and individual interviews with 16 learners with mild intellectual disability at two special schools in South Africa. This was followed by individual interviews with the school nurse and social worker, and an analysis of schools' books of incidents. Factors contributing to sexual violence at schools for learners with mild intellectual disability included: (i) peer pressure, (ii) concealment of reported incidents of sexual violence, (iii) unsupervised areas linked to schools and (iv) arranged relationships. The following suggestions are put forth: (i) awareness programmes, (ii) sensitization of teachers about the consequences and prevention of sexual violence, (iii) boundaries within which the arranged relationship occurs, (iv) intensification of sexuality education and (v) supervision around the school premises. © 2015 John Wiley & Sons Ltd.

  3. Stability and change in forest-based communities: a selected bibliography.

    Science.gov (United States)

    Catherine Woods Richardson

    1996-01-01

    This bibliography lists literature dealing with the concept of community stability, the condition of forest-based communities, and the relations between forest management and local community conditions. Most citations are from the 1970s to the mid 1990s, though some particularly pertinent earlier works also appear. The emphasis is on forest-based communities in the...

  4. Importance of asparagine on the conformational stability and chemical reactivity of selected anti-inflammatory peptides

    Energy Technology Data Exchange (ETDEWEB)

    Soriano-Correa, Catalina, E-mail: csorico@comunidad.unam.mx [Química Computacional, Facultad de Estudios Superiores (FES)-Zaragoza, Universidad Nacional Autónoma de México (UNAM), Iztapalapa, C.P. 09230 México, D.F. (Mexico); Barrientos-Salcedo, Carolina [Laboratorio de Química Médica y Quimiogenómica, Facultad de Bioanálisis Campus Veracruz-Boca del Río, Universidad Veracruzana, C.P. 91700 Veracruz (Mexico); Campos-Fernández, Linda; Alvarado-Salazar, Andres [Química Computacional, Facultad de Estudios Superiores (FES)-Zaragoza, Universidad Nacional Autónoma de México (UNAM), Iztapalapa, C.P. 09230 México, D.F. (Mexico); Esquivel, Rodolfo O. [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa (UAM-Iztapalapa), C.P. 09340 México, D.F. (Mexico)

    2015-08-18

    Highlights: • Asparagine plays an important role to anti-inflammatory effect of peptides. • The electron-donor substituent groups favor the formation of the hydrogen bonds, which contribute in the structural stability of peptides. • Chemical reactivity and the physicochemical features are crucial in the biological functions of peptides. - Abstract: Inflammatory response events are initiated by a complex series of molecular reactions that generate chemical intermediaries. The structure and properties of peptides and proteins are determined by the charge distribution of their side chains, which play an essential role in its electronic structure and physicochemical properties, hence on its biological functionality. The aim of this study was to analyze the effect of changing one central amino acid, such as substituting asparagine for aspartic acid, from Cys–Asn–Ser in aqueous solution, by assessing the conformational stability, physicochemical properties, chemical reactivity and their relationship with anti-inflammatory activity; employing quantum-chemical descriptors at the M06-2X/6-311+G(d,p) level. Our results suggest that asparagine plays a more critical role than aspartic acid in the structural stability, physicochemical features, and chemical reactivity of these tripeptides. Substituent groups in the side chain cause significant changes on the conformational stability and chemical reactivity, and consequently on their anti-inflammatory activity.

  5. Enhanced thermal stability of the thylakoid membranes from spruce. A comparison with selected angiosperms

    Czech Academy of Sciences Publication Activity Database

    Karlický, Václav; Kurasová, Irena; Ptáčková, B.; Večeřová, Kristýna; Urban, Otmar; Špunda, Vladimír

    2016-01-01

    Roč. 130, 1-3 (2016), s. 357-371 ISSN 0166-8595 R&D Projects: GA MŠk(CZ) LO1415; GA ČR GA13-28093S Institutional support: RVO:67179843 Keywords : Norway spruce * Thermal stability * Circular dichroism * Photosystem II organization * Thylakoid membrane Subject RIV: ED - Physiology Impact factor: 3.864, year: 2016

  6. Sexual conflict

    NARCIS (Netherlands)

    Lessells, C.M.

    2012-01-01

    Parental care includes a wide variety of traits that enhance offspring development and survival. It is taxonomically widespread and is central to the maintenance of biodiversity through its close association with other phenomena such as sexual selection, life-history evolution, sex allocation,

  7. Temporal genetic stability in natural populations of the waterflea Daphnia magna in response to strong selection pressure.

    Science.gov (United States)

    Orsini, Luisa; Marshall, Hollie; Cuenca Cambronero, Maria; Chaturvedi, Anurag; Thomas, Kelley W; Pfrender, Michael E; Spanier, Katina I; De Meester, Luc

    2016-12-01

    Studies monitoring changes in genetic diversity and composition through time allow a unique understanding of evolutionary dynamics and persistence of natural populations. However, such studies are often limited to species with short generation times that can be propagated in the laboratory or few exceptional cases in the wild. Species that produce dormant stages provide powerful models for the reconstruction of evolutionary dynamics in the natural environment. A remaining open question is to what extent dormant egg banks are an unbiased representation of populations and hence of the species' evolutionary potential, especially in the presence of strong environmental selection. We address this key question using the water flea Daphnia magna, which produces dormant stages that accumulate in biological archives over time. We assess temporal genetic stability in three biological archives, previously used in resurrection ecology studies showing adaptive evolutionary responses to rapid environmental change. We show that neutral genetic diversity does not decline with the age of the population and it is maintained in the presence of strong selection. In addition, by comparing temporal genetic stability in hatched and unhatched populations from the same biological archive, we show that dormant egg banks can be consulted to obtain a reliable measure of genetic diversity over time, at least in the multidecadal time frame studied here. The stability of neutral genetic diversity through time is likely mediated by the buffering effect of the resting egg bank. © 2016 John Wiley & Sons Ltd.

  8. Stability in chromosome number and DNA content in synthetic tetraploids of Lolium multiflorum after two generations of selection

    Directory of Open Access Journals (Sweden)

    Roselaine Cristina Pereira

    Full Text Available ABSTRACT: Chromosome doubling of Italian ryegrass genotypes ( Lolium multiflorum Lam. adapted to the brazilian edaphoclimatic conditions is an important strategy used by breeders and aims to obtain more vigorous genotypes with better forage quality and disease resistance. The effectiveness of chromosome doubling can be measured by genetic stability and fertility rates of plants over generations. However, a common problem in the polyploidization process is the regeneration of mixoploid plants that have impaired fertility and genetic stability. The objective of this study was to verify if progenies of recently tetraploidized plants remain stable regarding DNA content and chromosome number, over two generations. Progenies of L. multiflorum plants artificially tetraploidized with colchicine treatment were evaluated. Chromosome counting and estimates of the DNA content were used to evaluate the genetic stability. The percentage of tetraploid plants (4X increased over generations (18%, 34% and 91% in cycle 0, 1 and 2, respectively. All progenies identified as tetraploid by flow citometry showed variation in chromosome number (mixoploidy, but produced viable seeds. Results showed that stabilization in chromosome number and DNA content in tetraploidized plant progenies requires time and that the success of this procedure depends on a continuous and accurate screening and selection.

  9. Sexual Identity, Sex of Sexual Contacts, and Health-Related Behaviors among Students in Grades 9-12--United States and Selected Sites, 2015. Morbidity and Mortality Weekly Report. Surveillance Summaries. Volume 65, Number 9

    Science.gov (United States)

    Kann, Laura; Olsen, Emily O'Malley; McManus, Tim; Harris, William A.; Shanklin, Shari L.; Flint, Katherine H.; Queen, Barbara; Lowry, Richard; Chyen, David; Whittle, Lisa; Thornton, Jemekia; Lim, Connie; Yamakawa, Yoshimi; Brener, Nancy; Zaza, Stephanie

    2016-01-01

    Problem: Sexual identity and sex of sexual contacts can both be used to identify sexual minority youth. Significant health disparities exist between sexual minority and nonsexual minority youth. However, not enough is known about health-related behaviors that contribute to negative health outcomes among sexual minority youth and how the prevalence…

  10. Site selection of active damper for stabilizing power electronics based power distribution system

    DEFF Research Database (Denmark)

    Yoon, Changwoo; Wang, Xiongfei; Bak, Claus Leth

    2015-01-01

    electronics based power device, which provides an adjustable damping capability to the power system where the voltage harmonic instability is measured. It can stabilize by adjusting the equivalent node impedance with its plug and play feature. This feature gives many degrees of freedom of its installation......Stability in the nowadays distribution power system is endangered by interaction problems that may arise from newly added power-electronics based power devices. Recently, a new concept to deal with this higher frequency instability, the active damper, has been proposed. The active damper is a power...... point when the system has many nodes. Therefore, this paper addresses the proper placement of an active damper in an unstable small-scale power distribution system. A time-domain model of the Cigre benchmark low-vltage network is used as a test field. The result shows the active damper location...

  11. Water-stability of soil aggregates in relation to selected properties

    International Nuclear Information System (INIS)

    Mbagwu, J.S.C.; Bazzoffi, P.; Unamba Oparah, I.

    1995-03-01

    The stability of soil aggregates in water is an important soil physical property for evaluating the potential of agricultural soils to erode and elucidating the mechanisms of soil erosion. In this study we used aggregates from 15 surface soil samples in Italy to evaluate the influence of intrinsic soil physical, chemical and mineralogical properties on aggregates stability (AS). The aim was to develop a model for predicting AS from a subset of these soil properties. The index of stability used is the mean-weight diameter of water-stable aggregates (MWD). The model developed with soil physical properties alone explained just 42% of variance in MWD and predicted AS in only 20% of test soils. The model developed with mineralogical properties alone explained 70% of variance in MWD and predicted AS in 60% of the test soils. The chemical properties - based model explained 90% of variance in MWD and predicted AS in 80% of the test soils. The best-fit model was developed with soil properties from the physical, chemical and mineralogical subsets. It explained 98% of variance in MWD and predicted AS in 100% of the test soils. This model shows that the most important soil properties which influence the AS of these soils include ratio of total sand to clay, concentrations of iron oxide, magnesium oxide, organic matter, silica/alumina ratio, chlorite, feldspar and muscovite. This indicates that fairly good estimates of the relative stability of these aggregates in water and hence of their potential to erode, requires a knowledge of the physico-chemical and mineralogical properties. (author). 40 refs, 4 tabs

  12. General Investigation of Tidal Inlets: Stability of Selected United States Tidal Inlets

    Science.gov (United States)

    1991-09-01

    characteristics in relation to the variability of the hydr; aulic parameters. An inlet can fall into any of four "stability" classes 48 Orientation Parameter 80...nlot he ~ :Ke(: t 93. If a fairly straight coast with uniform offshore slopes and a regionally homogeneous wave climate is considered, a reasonable...expectation is LhaL the longshore transport quantities and directions are homogeneous. Given a long-term variability in wave climate , a corresponding

  13. A neurobiological perspective on attachment problems in sexual offenders and the role of selective serotonin re-uptake inhibitors in the treatment of such problems.

    Science.gov (United States)

    Beech, Anthony R; Mitchell, Ian J

    2005-02-01

    This paper describes what is currently known about attachment from the development, social-cognitive and biological literatures and outlines the impact on organisms given adverse development experiences that can have an effect upon attachment formation in childhood across these three literatures. We then describe the effects that 'insecure' attachment styles arising in childhood can affect brain chemistry and brain function and subsequently adult social/romantic relationships. In the paper, we note that a number of sexual offenders report adverse childhood experiences and that they possess attachment styles that, taken together, make it likely that they will either seek out intimate attachments in ways where they will have sex with children, perhaps confusing sex with intimacy or in aggressive ways as particularly happens with men who sexually assault adult women. The last section of the paper describes chemical treatment for sexual offenders, focusing on the use of selective serotonin re-uptake inhibitors (SSRIs). We note evidence for the role of SSRIs in promoting more social/affiliative behaviors and speculate on the effects that SSRIs have in the treatment of sexual offenders by targeting areas of the social brain. Here, we would argue that it would be useful to carry out treatment where there is a combination of SSRI treatment (to promote more prosocial feelings and behaviors) in conjunction with therapy that typically addresses thoughts and behaviors, i.e., cognitive-behavioral therapy/schema-focused therapy.

  14. Dimensions of racism and their impact on partner selection among men of colour who have sex with men: understanding pathways to sexual risk.

    Science.gov (United States)

    Ro, Annie; Ayala, George; Paul, Jay; Choi, Kyung-Hee

    2013-01-01

    While many studies have established the relationship between experiences of racism and sexual risk among men of colour who have sex with men, the pathways by which this occurs are underdeveloped. To address this gap, we must better investigate the lived realities of racism in the gay community. In this study, we had the unique opportunity to examine experiences of racism among African American, Asian/Pacific Islander and Latino men who have sex with men living in Los Angeles through focus groups and individual in-depth interviews. We found three themes of racism: exclusion from West Hollywood and the mainstream gay community, sexual rejection based on race/ethnicity and sexual stereotypes. There were differences across the three racial groups in the experiences of each theme, however. We then considered how racism impacted partner selection and found that race played a salient role in determining power differentials within mixed-race partnerships. Finally, we discussed several future areas for research that can better establish pathways between racism and sexual risk.

  15. Dimensions of Racism and their Impact on Partner Selection among Men who have Sex with Men of Colour: Understanding Pathways to Sexual Risk

    Science.gov (United States)

    Ayala, George; Paul, Jay; Choi, Kyung-Hee

    2013-01-01

    While many studies have established the relationship between experiences of racism and sexual risk among men who have sex with men of colour, the pathways by which this occurs are underdeveloped. To address this gap, we must better investigate the lived realities of racism in the gay community. In this study, we had the unique opportunity to examine experiences of racism among African American, Latino and Asian/Pacific Islander men who have sex with men living in Los Angeles through focus groups and individual in-depth interviews. We found three themes of racism: exclusion from West Hollywood and the mainstream gay community, sexual rejection based on race/ethnicity, and sexual stereotypes. There were differences across the three racial groups in the experiences of each theme, however. We then considered how racism impacted partner selection and found that race played a salient role in determining power differentials within mixed-race partnerships. Finally, we discussed several future areas for research that can better establish pathways between racism and sexual risk. PMID:23659363

  16. Methodology for the selection of the regime of flow in lagoons of stabilization

    International Nuclear Information System (INIS)

    Cruz T, Luis Eduardo; Alayon Torres, Walter E; Monsegny S, Carlos Emilio

    2000-01-01

    To model biological processes, information is needed on the stoichiometry and kinetics of the reactions and about the hydraulic regime of the system. The stoichiometry of a reaction refers to the quantity of consumed reactants (such as substrates) and to the quantity of formed products (such as microorganisms). The hydraulic regime makes reference to the configuration of the flow inside of and outside of the process and to the mixture and distribution of the solids of the fluid inside the reactor. The present article it is centered in studying the different mixture regimens and its kinetic models of degradation of organic matter applied to the case specify of the lagoon of stabilization of residual waters of the Municipality of Tocancipa; also it the methodology discusses to determine the type of flow that is presented in a stabilization lagoon. The kinetic models of degradation of organic matter in stabilization lagoons are classified according with the presence or absence of oxygen in the lagoon and with the mixture regime that it is presented in this. The regimens of flow that are presented in the stabilization lagoons are those of complete mixture and the piston flow, one completely opposed to the other one. Between these two is the denominated regime of dispersed or arbitrary flow. The determination of the mixture regime is of great importance, since with this it is possible to have an idea of the behavior of the rates of removal of the nutrients that arrive to the system, of the consumption of oxygen and the kinetic pattern of removal of organic matter among others. The regime of mixture complete ideal this characterized because the mass of water that enters to the system is dispersed instantly, making that the characteristics of the water are the same ones in any point, that is to say that the reaction rates are constant in the reactor and the demand of oxygen it is identical in any sampling point, likewise it happens with the removal rate; this has big

  17. Shape-Selection of Thermodynamically Stabilized Colloidal Pd and Pt Nanoparticles Controlled via Support Effects

    DEFF Research Database (Denmark)

    Ahmadi, M.; Behafarid, F.; Holse, Christian

    2015-01-01

    Colloidal chemistry, in combination with nanoparticle (NP)/support epitaxial interactions is used here to synthesize shape-selected and thermodynamically stable metallic NPs over a broad range of NP sizes. The morphology of three-dimensional palladium and platinum NPs supported on TiO2(110) was i......Colloidal chemistry, in combination with nanoparticle (NP)/support epitaxial interactions is used here to synthesize shape-selected and thermodynamically stable metallic NPs over a broad range of NP sizes. The morphology of three-dimensional palladium and platinum NPs supported on TiO2...... rows and was found to be responsible for the shape control. The ability of synthesizing thermally stable shape-selected metal NPs demonstrated here is expected to be of relevance for applications in the field of catalysis, since the activity and selectivity of NP catalysts has been shown to strongly...

  18. Assessing the accuracy and stability of variable selection methods for random forest modeling in ecology

    Science.gov (United States)

    Random forest (RF) modeling has emerged as an important statistical learning method in ecology due to its exceptional predictive performance. However, for large and complex ecological datasets there is limited guidance on variable selection methods for RF modeling. Typically, e...

  19. Prokaryotic Selectivity, Anti-endotoxic Activity and Protease Stability of Diastereomeric and Enantiomeric Analogs of Human Antimicrobial Peptide LL-37

    International Nuclear Information System (INIS)

    Nan, Yong Hai; Lee, Bongju; Shin, Song Yub

    2012-01-01

    LL-37 is the only antimicrobial peptide (AMP) of the human cathelicidin family. In addition to potent antimicrobial activity, LL-37 is known to have the potential to inhibit lipolysaccharide (LPS)-induced endotoxic effects. To provide the stability to proteolytic digestion and increase prokaryotic selectivity and/or anti-endotoxic activity of two Lys/Trp-substituted 19-meric anti-microbial peptides (a4-W1 and a4-W2) designed from IG-19 (residues 13-31 of LL-37), we synthesized the diastereomeric peptides (a4-W1-D and a4-W2-D) with D-amino acid substitution at positions 3, 7, 10, 13 and 17 of a4-W1 and a4-W2, respectively and the enantiomeric peptides (a4-W1-E and a4-W2-E) composed D-amino acids. The diastereomeric peptides exhibited the best prokaryotic selectivity and effective protease stability, but no or less anti-endotoxic activity. In contrast, the enantiomeric peptides had not only prokaryotic selectivity and anti-endotoxic activity but also protease stability. Our results suggest that the hydrophobicity and α-helicity of the peptide is important for anti-endotoxic activity. In particular, the enantiomeric peptides showed potent anti-endotoxic and LPS-neutralizing activities comparable to that of LL-37. Taken together, both a4-W1-E and a4-W2-E holds promise as a template for the development of peptide antibiotics for the treatment of endotoxic shock and sepsis

  20. Prokaryotic Selectivity, Anti-endotoxic Activity and Protease Stability of Diastereomeric and Enantiomeric Analogs of Human Antimicrobial Peptide LL-37

    Energy Technology Data Exchange (ETDEWEB)

    Nan, Yong Hai; Lee, Bongju; Shin, Song Yub [Chosun Univ., Gwangju (Korea, Republic of)

    2012-09-15

    LL-37 is the only antimicrobial peptide (AMP) of the human cathelicidin family. In addition to potent antimicrobial activity, LL-37 is known to have the potential to inhibit lipolysaccharide (LPS)-induced endotoxic effects. To provide the stability to proteolytic digestion and increase prokaryotic selectivity and/or anti-endotoxic activity of two Lys/Trp-substituted 19-meric anti-microbial peptides (a4-W1 and a4-W2) designed from IG-19 (residues 13-31 of LL-37), we synthesized the diastereomeric peptides (a4-W1-D and a4-W2-D) with D-amino acid substitution at positions 3, 7, 10, 13 and 17 of a4-W1 and a4-W2, respectively and the enantiomeric peptides (a4-W1-E and a4-W2-E) composed D-amino acids. The diastereomeric peptides exhibited the best prokaryotic selectivity and effective protease stability, but no or less anti-endotoxic activity. In contrast, the enantiomeric peptides had not only prokaryotic selectivity and anti-endotoxic activity but also protease stability. Our results suggest that the hydrophobicity and α-helicity of the peptide is important for anti-endotoxic activity. In particular, the enantiomeric peptides showed potent anti-endotoxic and LPS-neutralizing activities comparable to that of LL-37. Taken together, both a4-W1-E and a4-W2-E holds promise as a template for the development of peptide antibiotics for the treatment of endotoxic shock and sepsis.

  1. Enhancing the stability of copper chromite catalysts for the selective hydrogenation of furfural using ALD overcoating

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hongbo; Lei, Yu; Kropf, A. Jeremy; Zhang, Guanghui; Elam, Jeffrey W.; Miller, Jeffrey T.; Sollberger, Fred; Ribeiro, Fabio; Akatay, M. Cem; Stach, Eric A.; Dumesic, James A.; Marshall, Christopher L.

    2014-08-01

    The stability of a gas-phase furfural hydrogenation catalyst (CuCr2O4 center dot CuO) was enhanced by depositing a thin Al2O3 layer using atomic layer deposition (ALD). Based on temperature-programed reduction (TPR) measurements, the reduction temperature of Cu was raised significantly, and the activation energy for furfural reduction was decreased following the ALD treatment. Thinner ALD layers yielded higher furfural hydrogenation activities. X-ray absorption fine structure (XAFS) spectroscopy studies indicated that Cu1+/Cu-0 are the active species for furfural reduction.

  2. The genus Allogamus Schmid, 1955 (Trichoptera, Limnephilidae: revised by sexual selection-driven adaptive, non-neutral traits of the phallic organ

    Directory of Open Access Journals (Sweden)

    Oláh, János

    2014-06-01

    Full Text Available Based upon our previous reviews on the phylogenetic species concept, initial split criteria and fine structure analysis here we summarize population and model thinking as support to our diverged structure matrix procedure to test simply visually or, if required, by geometric morphometrics the stability of sexual selection-driven adaptive, non-neutral traits of the phallic organ. Complexity review helped us to establish plesiomorphic and apomorphic states of parameres of the phallic organ. Fine structure diversity of the adaptive traits of paramere and the apical portion of aedeagus has been applied to revise the Allogamus genus. All the known 22 taxa, 19 species and 3 subspecies, have been revised. Apomorphic fusion of parameres and complexity evolution of aedeagus directed us to erect 2 rediagnosed species groups, 1 new species group, 4 new species subgroups, 1 new species complex, 10 new species and 4 new or revised species status as follows: Allogamus auricollis species group, rediagnosed. Allogamus antennatus new subgroup: A. antennatus (McLachlan, 1876, A. ausoniae Moretti, 1991, stat. rev., A. morettii DePietro & Cianficconi, 2001, stat. rev., A. silanus Moretti 1991, stat. nov. Allogamus auricollis new subgroup: A. alpensis Oláh, Lodovici & Valle sp. nov., A. auricollis (Pictet, 1834, A. despaxi Decamps, 1967, A. zomok Oláh & Coppa sp. nov. Allogamus hilaris new subgroup: A. hilaris (McLachlan, 1876. Allogamus ligonifer new subgroup: A. gibraltaricus Gonzalez & Ruiz, 2001, A. kefes Coppa & Oláh sp. nov., A. laureatus (Navas, 1918, A. ligonifer (McLachlan, 1876, A. pertuli Malicky, 1974, A. pupos Coppa & Oláh sp. nov. Allogamus mortoni new species complex: A. kampos Oláh & Ruiz sp. nov., A. kettos Oláh & Ruiz sp. nov., A. kurtas Oláh & Zamora-Muñoz sp. nov., A. mortoni (Navas, 1907, A. pohos Oláh & Zamora-Muñoz sp. nov., A. tuskes Oláh & Sáinz-Bariáin sp. nov. Allogamus corsicus new species group: A. corsicus (Ris, 1897. A

  3. First Principles Prediction of Structure, Structure Selectivity, and Thermodynamic Stability under Realistic Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ceder, Gerbrand [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Materials and Engineering

    2018-01-28

    Novel materials are often the enabler for new energy technologies. In ab-initio computational materials science, method are developed to predict the behavior of materials starting from the laws of physics, so that properties can be predicted before compounds have to be synthesized and tested. As such, a virtual materials laboratory can be constructed, saving time and money. The objectives of this program were to develop first-principles theory to predict the structure and thermodynamic stability of materials. Since its inception the program focused on the development of the cluster expansion to deal with the increased complexity of complex oxides. This research led to the incorporation of vibrational degrees of freedom in ab-initio thermodynamics, developed methods for multi-component cluster expansions, included the explicit configurational degrees of freedom of localized electrons, developed the formalism for stability in aqueous environments, and culminated in the first ever approach to produce exact ground state predictions of the cluster expansion. Many of these methods have been disseminated to the larger theory community through the Materials Project, pymatgen software, or individual codes. We summarize three of the main accomplishments.

  4. Selection for Protein Kinetic Stability Connects Denaturation Temperatures to Organismal Temperatures and Provides Clues to Archaean Life.

    Directory of Open Access Journals (Sweden)

    M Luisa Romero-Romero

    Full Text Available The relationship between the denaturation temperatures of proteins (Tm values and the living temperatures of their host organisms (environmental temperatures: TENV values is poorly understood. Since different proteins in the same organism may show widely different Tm's, no simple universal relationship between Tm and TENV should hold, other than Tm≥TENV. Yet, when analyzing a set of homologous proteins from different hosts, Tm's are oftentimes found to correlate with TENV's but this correlation is shifted upward on the Tm axis. Supporting this trend, we recently reported Tm's for resurrected Precambrian thioredoxins that mirror a proposed environmental cooling over long geological time, while remaining a shocking ~50°C above the proposed ancestral ocean temperatures. Here, we show that natural selection for protein kinetic stability (denaturation rate can produce a Tm↔TENV correlation with a large upward shift in Tm. A model for protein stability evolution suggests a link between the Tm shift and the in vivo lifetime of a protein and, more specifically, allows us to estimate ancestral environmental temperatures from experimental denaturation rates for resurrected Precambrian thioredoxins. The TENV values thus obtained match the proposed ancestral ocean cooling, support comparatively high Archaean temperatures, and are consistent with a recent proposal for the environmental temperature (above 75°C that hosted the last universal common ancestor. More generally, this work provides a framework for understanding how features of protein stability reflect the environmental temperatures of the host organisms.

  5. Stability of a Model Explaining Selected Extramusical Influences on Solo and Small-Ensemble Festival Ratings

    Science.gov (United States)

    Bergee, Martin J.; Westfall, Claude R.

    2005-01-01

    This is the third study in a line of inquiry whose purpose has been to develop a theoretical model of selected extra musical variables' influence on solo and small-ensemble festival ratings. Authors of the second of these (Bergee & McWhirter, 2005) had used binomial logistic regression as the basis for their model-formulation strategy. Their…

  6. Residue-based Coordinated Selection and Parameter Design of Multiple Power System Stabilizers (PSSs)

    DEFF Research Database (Denmark)

    Su, Chi; Hu, Weihao; Fang, Jiakun

    2013-01-01

    data from time domain simulations. Then a coordinated approach for multiple PSS selection and parameter design based on residue method is proposed and realized in MATLAB m-files. Particle swarm optimization (PSO) is adopted in the coordination process. The IEEE 39-bus New England system model...

  7. The influence of selection for protein stability on dN/dS estimations

    DEFF Research Database (Denmark)

    Dasmeh, Pouria; Serohijos, Adrian W. R.; Kepp, Kasper Planeta

    2014-01-01

    Understanding the relative contributions of various evolutionary processes-purifying selection, neutral drift, and adaptation-is fundamental to evolutionary biology. A common metric to distinguish these processes is the ratio of nonsynonymous to synonymous substitutions (i.e., dN/dS) interpreted ...

  8. Chemical variation in a dominant tree species: population divergence, selection and genetic stability across environments.

    Directory of Open Access Journals (Sweden)

    Julianne M O'Reilly-Wapstra

    Full Text Available Understanding among and within population genetic variation of ecologically important plant traits provides insight into the potential evolutionary processes affecting those traits. The strength and consistency of selection driving variability in traits would be affected by plasticity in differences among genotypes across environments (G×E. We investigated population divergence, selection and environmental plasticity of foliar plant secondary metabolites (PSMs in a dominant tree species, Eucalyptus globulus. Using two common garden trials we examined variation in PSMs at multiple genetic scales; among 12 populations covering the full geographic range of the species and among up to 60 families within populations. Significant genetic variation in the expression of many PSMs resides both among and within populations of E. globulus with moderate (e.g., sideroxylonal A h(2op = 0.24 to high (e.g., macrocarpal G h(2op = 0.48 narrow sense heritabilities and high coefficients of additive genetic variation estimated for some compounds. A comparison of Qst and Fst estimates suggest that variability in some of these traits may be due to selection. Importantly, there was no genetic by environment interaction in the expression of any of the quantitative chemical traits despite often significant site effects. These results provide evidence that natural selection has contributed to population divergence in PSMs in E. globulus, and identifies the formylated phloroglucinol compounds (particularly sideroxylonal and a dominant oil, 1,8-cineole, as candidates for traits whose genetic architecture has been shaped by divergent selection. Additionally, as the genetic differences in these PSMs that influence community phenotypes is stable across environments, the role of plant genotype in structuring communities is strengthened and these genotypic differences may be relatively stable under global environmental changes.

  9. Sexual Assault

    Science.gov (United States)

    ... Professions Indian Health Careers Indian Preference Loan Repayment Military Transition Student ... Sexual Assault Sexual assault is a significant problem affecting American Indians and Alaska Natives. Sexual assault ...

  10. Sleeping site selection by agile gibbons: the influence of tree stability, fruit availability and predation risk.

    Science.gov (United States)

    Cheyne, Susan M; Höing, Andrea; Rinear, John; Sheeran, Lori K

    2012-01-01

    Primates spend a significant proportion of their lives at sleeping sites: the selection of a secure and stable sleeping tree can be crucial for individual survival and fitness. We measured key characteristics of all tree species in which agile gibbons slept, including exposure of the tree crown, root system, height, species and presence of food. Gibbons most frequently slept in Dipterocarpaceae and Fabaceae trees and preferentially chose trees taller than average, slept above the mean canopy height and showed a preference for liana-free trees. These choices could reflect avoidance of competition with other frugivores, but we argue these choices reflect gibbons prioritizing avoidance of predation. The results highlight that gibbons are actively selecting and rejecting sleeping trees based on several characteristics. The importance of the presence of large trees for food is noted and provides insight into gibbon antipredatory behaviour. Copyright © 2013 S. Karger AG, Basel.

  11. Sexual Identity, Sex of Sexual Contacts, and Health-Risk Behaviors among Students in Grades 9-12--Youth Risk Behavior Surveillance, Selected Sites, United States, 2001-2009. Morbidity and Mortality Weekly Report. Early Release. Volume 60

    Science.gov (United States)

    Kann, Laura; O'Malley Olsen, Emily; McManus, Tim; Kinchen, Steve; Chyen, David; Harris, William A.; Wechsler, Howell

    2011-01-01

    Problem: Sexual minority youths are youths who identify themselves as gay or lesbian, bisexual, or unsure of their sexual identity or youths who have only had sexual contact with persons of the same sex or with both sexes. Population-based data on the health-risk behaviors practiced by sexual minority youths are needed at the state and local…

  12. Factors Contributing to Sexual Violence at Selected Schools for Learners with Mild Intellectual Disability in South Africa

    Science.gov (United States)

    Nyokangi, Doris; Phasha, Nareadi

    2016-01-01

    Background: This paper reports part of the findings of a study which exposed sexual violence in schools for learners with mild intellectual disability in South Africa. Special attention was paid on factors contributing to such a problem. Methods: Data were collected using focus groups and individual interviews with 16 learners with mild…

  13. Media Portrayals of Love, Marriage & Sexuality for Child Audiences: A Select Content Analysis of Walt Disney Animated Family Films.

    Science.gov (United States)

    Junn, Ellen N.

    This study examined the portrayal of love, marriage, and sexuality in 11 romantic and nonromantic Disney animated films. Results showed that four out of five of the nonromantic films had male leads, with males occupying significantly more screen time than females. Half of the romantic films had female leads, who occupied significantly more screen…

  14. The effects of ozonation on select waterborne steroid hormones in recirculation aquaculture systems containing sexually mature Atlantic salmon Salmo salar

    Science.gov (United States)

    A controlled 3-month study was conducted in 6 replicated water recirculation aquaculture systems (RAS) containing a mixture of sexually mature and immature Atlantic salmon Salmo salar to determine whether water ozonation is associated with a reduction in waterborne hormones. Post-smolt Atlantic salm...

  15. School Sexuality Education: Opposition and Answers. Materials from the Katharine Dexter McCormick Library: A Selective, Annotated Bibliography.

    Science.gov (United States)

    Modig, Zeau D., Ed.

    This annotated bibliography was compiled as a guide for educators, administrators, counselors, parents, and everyone concerned about the opponents of sexuality education in schools, their arguments, and their tactics. Entries were chosen to represent a variety of materials in terms of both format and content. This bibliography is divided into…

  16. OXIDATIVE STABILITY OF CHILLED CHICKEN MEAT AFTER FEEDING OF SELECTED PLANTS

    Directory of Open Access Journals (Sweden)

    Mária Martonová

    2010-07-01

    Full Text Available  The effect of feeding of lemon balm (Melissa officinalis, L and combination of yarrow (Achillea millefolium L and hawthorn (Crataegus oxyacantha L on oxidative stability and sensory properties of produced poultry meat was investigated. Sixty one-day-old commercial broiler chicks (ROSS 308 were used in our experiment, divided into 3 groups, and fed 41 days, as follows: control (K was fed with standard diet without supplementation of plants; second group (M was fed with standard diet supplemented with grounded lemon balm in concentration 2 % per 1 kg; and third group was fed with standard diet supplemented with grounded yarrow (2 % and hawthorn (1 %. Results showed that supplementation with lemon balm, and mainly combination of yarrow and hawthorn in the diet significantly caused reduction of lipid oxidation processes in thigh meat during chilling storage of samples. In addition, supplementation of plants in the diet had positive effect on sensory quality of meat of broiler chickens.    doi:10.5219/38 

  17. Contrasting the beam interaction characteristics of selected lasers with a partially stabilized zirconia bio-ceramic

    International Nuclear Information System (INIS)

    Lawrence, J.

    2002-01-01

    Differences in the beam interaction characteristics of a CO 2 laser, a Nd:YAG laser, a high power diode laser (HPDL) and an excimer laser with a partially stabilized zirconia bio-ceramic have been studied. A derivative of Beer-Lambert's law was applied and the laser beam absorption lengths of the four lasers were calculated as 33.55x10 -3 cm for the CO 2 laser, 18.22x10 -3 cm for the Nd : YAG laser, 17.17x10 -3 cm for the HPDL and 8.41x10 -6 cm for the excimer laser. It was determined graphically that the fluence threshold values at which significant material removal was effected by the CO 2 laser, the Nd:YAG laser, the HPDL and the excimer laser were 52 J cm -2 , 97 J cm -2 , 115 J cm -2 and 0.48 J cm -2 , respectively. The thermal loading value for the CO 2 laser, the Nd : YAG laser, the HPDL and the excimer laser were calculated as being 1.55 kJ cm -3 , 5.32 kJ cm 3 , 6.69 kJ cm -3 and 57.04 kJ cm -3 , respectively. (author)

  18. Selective removal of erythromycin by magnetic imprinted polymers synthesized from chitosan-stabilized Pickering emulsion.

    Science.gov (United States)

    Ou, Hongxiang; Chen, Qunhui; Pan, Jianming; Zhang, Yunlei; Huang, Yong; Qi, Xueyong

    2015-05-30

    Magnetic imprinted polymers (MIPs) were synthesized by Pickering emulsion polymerization and used to adsorb erythromycin (ERY) from aqueous solution. The oil-in-water Pickering emulsion was stabilized by chitosan nanoparticles with hydrophobic Fe3O4 nanoparticles as magnetic carrier. The imprinting system was fabricated by radical polymerization with functional and crosslinked monomer in the oil phase. Batches of static and dynamic adsorption experiments were conducted to analyze the adsorption performance on ERY. Isotherm data of MIPs well fitted the Freundlich model (from 15 °C to 35 °C), which indicated heterogeneous adsorption for ERY. The ERY adsorption capacity of MIPs was about 52.32 μmol/g at 15 °C. The adsorption kinetics was well described by the pseudo-first-order model, which suggested that physical interactions were primarily responsible for ERY adsorption. The Thomas model used in the fixed-bed adsorption design provided a better fit to the experimental data. Meanwhile, ERY exhibited higher affinity during adsorption on the MIPs compared with the adsorption capacity of azithromycin and chloramphenicol. The MIPs also exhibited excellent regeneration capacity with only about 5.04% adsorption efficiency loss in at least three repeated adsorption-desorption cycles. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Bias and Stability of Single Variable Classifiers for Feature Ranking and Selection.

    Science.gov (United States)

    Fakhraei, Shobeir; Soltanian-Zadeh, Hamid; Fotouhi, Farshad

    2014-11-01

    Feature rankings are often used for supervised dimension reduction especially when discriminating power of each feature is of interest, dimensionality of dataset is extremely high, or computational power is limited to perform more complicated methods. In practice, it is recommended to start dimension reduction via simple methods such as feature rankings before applying more complex approaches. Single Variable Classifier (SVC) ranking is a feature ranking based on the predictive performance of a classifier built using only a single feature. While benefiting from capabilities of classifiers, this ranking method is not as computationally intensive as wrappers. In this paper, we report the results of an extensive study on the bias and stability of such feature ranking method. We study whether the classifiers influence the SVC rankings or the discriminative power of features themselves has a dominant impact on the final rankings. We show the common intuition of using the same classifier for feature ranking and final classification does not always result in the best prediction performance. We then study if heterogeneous classifiers ensemble approaches provide more unbiased rankings and if they improve final classification performance. Furthermore, we calculate an empirical prediction performance loss for using the same classifier in SVC feature ranking and final classification from the optimal choices.

  20. Impacts of select organic ligands on the colloidal stability, dissolution dynamics, and toxicity of silver nanoparticles.

    Science.gov (United States)

    Pokhrel, Lok R; Dubey, Brajesh; Scheuerman, Phillip R

    2013-11-19

    Key understanding of potential transformations that may occur on silver nanoparticle (AgNP) surface upon interaction with naturally ubiquitous organic ligands (e.g., -SH (thoil), humic acid, or -COO (carboxylate)) is limited. Herein we investigated how dissolved organic carbon (DOC), -SH (in cysteine, a well-known Ag(+) chelating agent), and -COO (in trolox, a well-known antioxidant) could alter the colloidal stability, dissolution rate, and toxicity of citrate-functionalized AgNPs (citrate-AgNPs) against a keystone crustacean Daphnia magna. Cysteine, DOC, or trolox amendment of citrate-AgNPs differentially modified particle size, surface properties (charge, plasmonic spectra), and ion release dynamics, thereby attenuating (with cysteine or trolox) or promoting (with DOC) AgNP toxicity. Except with DOC amendment, the combined toxicity of AgNPs and released Ag under cysteine or trolox amendment was lower than of AgNO3 alone. The results of this study show that citrate-AgNP toxicity can be associated with oxidative stress, ion release, and the organism biology. Our evidence suggests that specific organic ligands available in the receiving waters can differentially surface modify AgNPs and alter their environmental persistence (changing dissolution dynamics) and subsequently the toxicity; hence, we caveat to generalize that surface modified nanoparticles upon environmental release may not be toxic to receptor organisms.

  1. Biting off more than you can chew: sexual selection on the free amino acid composition of the spermatophylax in decorated crickets

    Science.gov (United States)

    Gershman, Susan N.; Mitchell, Christopher; Sakaluk, Scott K.; Hunt, John

    2012-01-01

    Nuptial food gifts function to enhance male fertilization success, but their consumption is not always beneficial to females. In decorated crickets, the spermatophore transferred at mating includes a gelatinous mass, the spermatophylax, which is consumed by females after mating. However, females often discard spermatophylaxes shortly after mating, whereupon they terminate sperm transfer. We hypothesized that females discard gifts based on their assessment of the gift itself, and specifically the composition of free amino acids. We tested this hypothesis by comparing spermatophylaxes discarded by females after mating with those that were destined to be fully consumed, and employed multivariate selection analysis to quantify the strength and form of multivariate sexual selection operating on the free amino acid composition of gifts. The analysis yielded a saddle-shaped fitness surface with two local peaks. Different amino acid profiles appear to elicit continued feeding on the spermatophylax either because they offer the same level of gustatory appeal, or because they differentially affect both the gustatory appeal and texture of the spermatophylax. We conclude that the gustatory response of females to males' nuptial food gifts represents an important avenue of post-copulatory mate choice, imposing significant sexual selection on the free amino acid composition of the spermatophylax. PMID:22357263

  2. Differential investment in pre- vs. post-copulatory sexual selection reinforces a cross-continental reversal of sexual size dimorphism in Sepsis punctum (Diptera: Sepsidae).

    Science.gov (United States)

    Puniamoorthy, Nalini; Blanckenhorn, W U; Schäfer, M A

    2012-11-01

    Theory predicts that males have a limited amount of resources to invest in reproduction, suggesting a trade-off between traits that enhance mate acquisition and those that enhance fertilization success. Here, we investigate the relationship between pre- and post-copulatory investment by comparing the mating behaviour and reproductive morphology of four European and five North American populations of the dung fly Sepsis punctum (Diptera) that display a reversal of sexual size dimorphism (SSD). We show that the geographic reversal in SSD between the continents (male biased in Europe, female biased in North America) is accompanied by differential investment in pre- vs. post-copulatory traits. We find higher remating rates in European populations, where larger males acquire more matings and consequently have evolved relatively larger testes and steeper hyper-allometry with body size. American populations, in sharp contrast, display much reduced, if any, effect of body size on those traits. Instead, North American males demonstrate an increased investment in mate acquisition prior to copulation, with more mounting attempts and a distinctive abdominal courtship display that is completely absent in Europe. When controlling for body size, relative female spermathecal size is similar on both continents, so we find no direct evidence for the co-evolution of male and female internal reproductive morphology. By comparing allopatric populations of the same species that apparently have evolved different mating systems and consequently SSD, we thus indirectly demonstrate differential investment in pre- vs. post-copulatory mechanisms increasing reproductive success. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

  3. Structural stability, acidity, and halide selectivity of the fluoride riboswitch recognition site

    KAUST Repository

    Chawla, Mohit; Credendino, Raffaele; Poater, Albert; Oliva, Romina M.; Cavallo, Luigi

    2015-01-01

    Using static and dynamics DFT methods we show that the Mg2+/F-/phosphate/water cluster at the center of the fluoride riboswitch is stable by its own and, once assembled, does not rely on any additional factor from the overall RNA fold. Further, we predict that the pKa of the water molecule bridging two Mg cations is around 8.4. We also demonstrate that the halide selectivity of the fluoride riboswitch is determined by the stronger Mg-F bond, which is capable of keeping together the cluster. Replacing F- with Cl- results in a cluster that is unstable under dynamic conditions. Similar conclusions on the structure and energetics of the cluster in the binding pocket of fluoride-inhibited pyrophosphatase suggest that the peculiarity of fluoride is in its ability to establish much stronger metal-halide bonds.

  4. Structural stability, acidity, and halide selectivity of the fluoride riboswitch recognition site

    KAUST Repository

    Chawla, Mohit

    2015-01-14

    Using static and dynamics DFT methods we show that the Mg2+/F-/phosphate/water cluster at the center of the fluoride riboswitch is stable by its own and, once assembled, does not rely on any additional factor from the overall RNA fold. Further, we predict that the pKa of the water molecule bridging two Mg cations is around 8.4. We also demonstrate that the halide selectivity of the fluoride riboswitch is determined by the stronger Mg-F bond, which is capable of keeping together the cluster. Replacing F- with Cl- results in a cluster that is unstable under dynamic conditions. Similar conclusions on the structure and energetics of the cluster in the binding pocket of fluoride-inhibited pyrophosphatase suggest that the peculiarity of fluoride is in its ability to establish much stronger metal-halide bonds.

  5. Selection of a mineral binder for the stabilization - solidification of waste containing aluminum metal

    International Nuclear Information System (INIS)

    Lahalle, H.; Cau Dit Counes, C.; Lambertin, D.; Antonucci, P.; Delpech, S.

    2015-01-01

    The dismantling of nuclear facilities produces radioactive waste materials, some of which may contain aluminum metal. In a strongly alkaline medium, such as that encountered in conventional cementitious materials based on Portland cement, aluminum metal becomes corroded, with a continued production of dihydrogen. In order to develop a mineral matrix having enhanced compatibility with aluminum, a literature review was first undertaken to identify binders capable of reducing the pore solution pH compared with Portland cement. An experimental study was then carried out to measure the hydrogen production resulting from corrosion of aluminum metal rods encapsulated in the different selected cement pastes. The best results were achieved with magnesium phosphate cement, which released very little hydrogen over the duration of the study. This production could be reduced further by adding a corrosion inhibitor (lithium nitrate) to the mixing solution

  6. Core Stability and Core Selection in a Decentralized Labor Matching Market

    Directory of Open Access Journals (Sweden)

    Heinrich H. Nax

    2016-03-01

    Full Text Available We propose a dynamic model of decentralized many-to-one matching in the context of a competitive labor market. Through wage offers and wage demands, firms compete over workers and workers compete over jobs. Firms make hire-and-fire decisions dependent on the wages of their own workers and on the alternative workers available on the job market. Workers bargain for better jobs; either individually or collectively as unions, adjusting wage demands upward/downward depending on whether they are currently employed/unemployed. We show that such a process is absorbed into the core with probability one in finite time. Moreover, within the core, allocations are selected that are characterized by surplus splitting according to a bargaining solution such that (i firms and workforce share total revenue according to relative bargaining strengths, and (ii workers receive equal workforce shares above their individual outside options. These results bridge empirical evidence and provide a rich set of testable predictions.

  7. Stability of choice in the honey bee nest-site selection process.

    Science.gov (United States)

    Nevai, Andrew L; Passino, Kevin M; Srinivasan, Parthasarathy

    2010-03-07

    We introduce a pair of compartment models for the honey bee nest-site selection process that lend themselves to analytic methods. The first model represents a swarm of bees deciding whether a site is viable, and the second characterizes its ability to select between two viable sites. We find that the one-site assessment process has two equilibrium states: a disinterested equilibrium (DE) in which the bees show no interest in the site and an interested equilibrium (IE) in which bees show interest. In analogy with epidemic models, we define basic and absolute recruitment numbers (R(0) and B(0)) as measures of the swarm's sensitivity to dancing by a single bee. If R(0) is less than one then the DE is locally stable, and if B(0) is less than one then it is globally stable. If R(0) is greater than one then the DE is unstable and the IE is stable under realistic conditions. In addition, there exists a critical site quality threshold Q(*) above which the site can attract some interest (at equilibrium) and below which it cannot. We also find the existence of a second critical site quality threshold Q(**) above which the site can attract a quorum (at equilibrium) and below which it cannot. The two-site discrimination process, in which we examine a swarm's ability to simultaneously consider two sites differing in both site quality and discovery time, has a stable DE if and only if both sites' individual basic recruitment numbers are less than one. Numerical experiments are performed to study the influences of site quality on quorum time and the outcome of competition between a lower quality site discovered first and a higher quality site discovered second. 2009 Elsevier Ltd. All rights reserved.

  8. Theoretical stability assessment of uranyl phosphates and apatites: Selection of amendments for in situ remediation of uranium

    International Nuclear Information System (INIS)

    Raicevic, S.; Wright, J.V.; Veljkovic, V.; Conca, J.L.

    2006-01-01

    Addition of an amendment or reagent to soil/sediment is a technique that can decrease mobility and reduce bioavailability of uranium (U) and other heavy metals in the contaminated site. According to data from literature and results obtained in field studies, the general mineral class of apatites was selected as a most promising amendment for in situ immobilization/remediation of U. In this work we presented theoretical assessment of stability of U(VI) in four apatite systems (hydroxyapatite (HAP), North Carolina Apatite (NCA), Lisina Apatite (LA), and Apatite II) in order to determine an optimal apatite soil amendment which could be used for in situ remediation of uranium. In this analysis we used a theoretical criterion which is based on calculation of the ion-ion interaction potential, representing the main term of the cohesive energy of the matrix/pollutant system. The presented results of this analysis indicate (i) that the mechanism of immobilization of U by natural apatites depends on their chemical composition and (ii) that all analyzed apatites represent, from the point of view of stability, promising materials which could be used in field remediation of U-contaminated sites

  9. Selective retardation of perfume oil evaporation from oil-in-water emulsions stabilized by either surfactant or nanoparticles.

    Science.gov (United States)

    Binks, Bernard P; Fletcher, Paul D I; Holt, Benjamin L; Beaussoubre, Pascal; Wong, Kenneth

    2010-12-07

    We have used dynamic headspace analysis to investigate the evaporation rates of perfume oils from stirred oil-in-water emulsions into a flowing gas stream. We compare the behavior of an oil of low water solubility (limonene) and one of high water solubility (benzyl acetate). It is shown how the evaporation of an oil of low water solubility is selectively retarded and how the retardation effect depends on the oil volume fraction in the emulsion. We compare how the evaporation retardation depends on the nature of the adsorbed film stabilizing the emulsion. Surfactant films are less effective than adsorbed films of nanoparticles, and the retardation can be further enhanced by compression of the adsorbed nanoparticle films by preshrinking the emulsion drops.

  10. Selection of a mineral binder with potentialities for the stabilization/solidification of aluminum metal

    Energy Technology Data Exchange (ETDEWEB)

    Cau Dit Coumes, C., E-mail: celine.cau-dit-coumes@cea.fr [Commissariat à l’Energie Atomique et aux Energies Alternatives, CEA/DEN/MAR/DTCD/SPDE, BP17171, 30207 Bagnols-sur-Cèze cedex (France); Lambertin, D.; Lahalle, H.; Antonucci, P. [Commissariat à l’Energie Atomique et aux Energies Alternatives, CEA/DEN/MAR/DTCD/SPDE, BP17171, 30207 Bagnols-sur-Cèze cedex (France); Cannes, C.; Delpech, S. [Institut de Physique Nucléaire, CNRS, Univ. Paris-Sud 11, 91406 Orsay Cedex (France)

    2014-10-15

    Highlights: • Binders capable of reducing the pore solution pH compared with Portland cements are reviewed. • The binders are then tested against aluminum corrosion. • Corrosion of aluminum metal is minimal with magnesium phosphate cement. • The H{sub 2} release can be reduced still further by adding LiNO{sub 3} to the mixing solution. • Electrochemical characterizations show that aluminum tends to a passive state. - Abstract: In a strongly alkaline medium, such as that encountered in conventional cementitious materials based on Portland cement, aluminum metal is corroded, with continued production of hydrogen. In order to develop a mineral matrix having enhanced compatibility with aluminum, a literature review was first undertaken to identify binders capable of reducing the pore solution pH compared with Portland cement. An experimental study was then carried out to measure the hydrogen production resulting from corrosion of aluminum metal rods encapsulated in the different selected cement pastes. The best results were achieved with magnesium phosphate cement, which released very little hydrogen over the duration of the study. This production could be reduced still further by adding a corrosion inhibitor (lithium nitrate) to the mixing solution. Open circuit potential measurement and Electrochemical Impedance Spectroscopy of aluminum electrode encapsulated in two pastes based on Portland cement and magnesium phosphate cement showed different redox behaviors. In the Portland cement paste, the electrochemical data confirmed the corrosion of aluminum whereas this latter tended to a passive state in the magnesium phosphate binder.

  11. A Selective G-Quadruplex DNA-Stabilizing Ligand Based on a Cyclic Naphthalene Diimide Derivative

    Directory of Open Access Journals (Sweden)

    Md. Monirul Islam

    2015-06-01

    Full Text Available A cyclic naphthalene diimide (cyclic NDI, 1, carrying a benzene moiety as linker chain, was synthesized and its interaction with G-quadruplex DNAs of a-core and a-coreTT as a human telomeric DNA, c-kit and c-myc as DNA sequence at promoter region, or thrombin-binding aptamer (TBA studied based on UV-VIS and circular dichroism (CD spectroscopic techniques, thermal melting temperature measurement, and FRET-melting assay. The circular dichroism spectra showed that 1 induced the formation of different types of G-quadruplex DNA structure. Compound 1 bound to these G-quadruplexes with affinities in the range of 106–107 M−1 order and a 2:1 stoichiometry. Compound 1 showed 270-fold higher selectivity for a-core than dsDNA with a preferable a-core binding than a-coreTT, c-kit, c-myc and TBA in the presence of K+, which is supported by thermal melting studies. The FRET-melting assay also showed that 1 bound preferentially to human telomeric DNA. Compound 1 showed potent inhibition against telomerase activity with an IC50 value of 0.9 μM and preferable binding to G-quadruplexes DNA than our previously published cyclic NDI derivative 3 carrying a benzene moiety as longer linker chain.

  12. Effectiveness of Stability Indices for Bread Wheat Genotypes Selection to Water Deficit Tolerant

    Directory of Open Access Journals (Sweden)

    A Naderi

    2013-12-01

    Full Text Available In countries such as Iran which will be faced water deficit as the main challenge in the future and the food production is going to be dependent to water recourses, wheat water-deficit tolerant and adapted genotypes release is one of the most important strategies under such a condition. In order to study the adaptation and terminal water deficit stress tolerance, fifteen bread wheat lines and Chamran cultivar as the check were evaluated. This research was carried out at Ahvaz, Dezfool, Zabol and Darab, south warm region research stations, in 2007-08 and 2008-09, in two separated experiments (1-well-watered and 2- terminal water deficit stress, using complete randomized block design with three replications. Data were analyzed and genotypes response was evaluated based on tolerance indices. Results showed that the difference among stations, years, genotypes and double and triple effects of source variations were significant at 1% probability level. Mean grain yield was 4300 Kg/ha in first year, while grain yield increased significantly in second year and reached to 5692 Kg/ha. Mean grain yield were 5840 and 4591Kg/ha under well-watered and terminal water deficit stress conditions, respectively. Correlation coefficients among STI, GMP ،MP and K1STI were significant. Correlation coefficient between slop of linear regression of grain yield in response to drought stress intensity and grain yield under terminal water deficit stress was positively and, with K2STI, TOL and SSI was negatively significant. Grain yield index, (YIR the proportion of grain yield of each genotype to grand mean of grain yield of all genotypes was the most important components to define grain yield in stepwise regression under both experiment conditions. According to the results of this research and based on tolerance indices, lines No. 2, 14 and 15 were selected as the high potential- terminal water deficit stress tolerant genotypes.

  13. Differential regulation of msx genes in the development of the gonopodium, an intromittent organ, and of the "sword," a sexually selected trait of swordtail fishes (Xiphophorus).

    Science.gov (United States)

    Zauner, Hans; Begemann, Gerrit; Marí-Beffa, Manuel; Meyer, Axel

    2003-01-01

    The possession of a conspicuous extension of colored ventral rays of the caudal fin in male fish of swordtails (genus Xiphophorus) is a prominent example for a trait that evolved by sexual selection. To understand the evolutionary history of this so-called sword molecularly, it is of interest to unravel the developmental pathways responsible for extended growth of sword rays during development of swordtail males. We isolated two msx genes and showed that they are differentially regulated during sword outgrowth. During sword growth in juvenile males, as well as during testosterone-induced sword development and fin ray regeneration in the sword after amputation, expression of msxC is markedly up-regulated in the sword forming fin rays. In contrast, msxE/1 is not differentially expressed in ventral and dorsal male fin rays, suggesting a link between the development of male secondary sexual characters in fins and up-regulation of msxC expression. In addition, we showed that msx gene expression patterns differ significantly between Xiphophorus and zebrafish. We also included in our study the gonopodium, a testosterone-dependent anal fin modification that serves as a fertilization organ in males of live-bearing fishes. Our finding that increased levels of msxC expression are associated with the testosterone-induced outgrowth of the gonopodium might suggest either that at least parts of the signaling pathways that pattern the evolutionary older gonopodium have been coopted to evolve a sexually selected innovation such as the sword or that increased msxC expression may be inherent to the growth process of long fin rays in general.

  14. Mating systems, reproductive success, and sexual selection in secretive species: a case study of the western diamond-backed rattlesnake, Crotalus atrox.

    Science.gov (United States)

    Clark, Rulon W; Schuett, Gordon W; Repp, Roger A; Amarello, Melissa; Smith, Charles F; Herrmann, Hans-Werner

    2014-01-01

    Long-term studies of individual animals in nature contribute disproportionately to our understanding of the principles of ecology and evolution. Such field studies can benefit greatly from integrating the methods of molecular genetics with traditional approaches. Even though molecular genetic tools are particularly valuable for species that are difficult to observe directly, they have not been widely adopted. Here, we used molecular genetic techniques in a 10-year radio-telemetric investigation of the western diamond-backed rattlesnake (Crotalus atrox) for an analysis of its mating system and to measure sexual selection. Specifically, we used microsatellite markers to genotype 299 individuals, including neonates from litters of focal females to ascertain parentage using full-pedigree likelihood methods. We detected high levels of multiple paternity within litters, yet found little concordance between paternity and observations of courtship and mating behavior. Larger males did not father significantly more offspring, but we found evidence for size-specific male-mating strategies, with larger males guarding females for longer periods in the mating seasons. Moreover, the spatial proximity of males to mothers was significantly associated with reproductive success. Overall, our field observations alone would have been insufficient to quantitatively measure the mating system of this population of C. atrox, and we thus urge more widespread adoption of molecular tools by field researchers studying the mating systems and sexual selection of snakes and other secretive taxa.

  15. NUMBER OF SUCCESSIVE CYCLES NECESSARY TO ACHIEVE STABILITY OF SELECTED GROUND REACTION FORCE VARIABLES DURING CONTINUOUS JUMPING

    Directory of Open Access Journals (Sweden)

    Jasmes M.W. Brownjohn

    2009-12-01

    Full Text Available Because of inherent variability in all human cyclical movements, such as walking, running and jumping, data collected across a single cycle might be atypical and potentially unable to represent an individual's generalized performance. The study described here was designed to determine the number of successive cycles due to continuous, repetitive countermovement jumping which a test subject should perform in a single experimental session to achieve stability of the mean of the corresponding continuously measured ground reaction force (GRF variables. Seven vertical GRF variables (period of jumping cycle, duration of contact phase, peak force amplitude and its timing, average rate of force development, average rate of force relaxation and impulse were extracted on the cycle-by-cycle basis from vertical jumping force time histories generated by twelve participants who were jumping in response to regular electronic metronome beats in the range 2-2.8 Hz. Stability of the selected GRF variables across successive jumping cycles was examined for three jumping rates (2, 2.4 and 2.8 Hz using two statistical methods: intra-class correlation (ICC analysis and segmental averaging technique (SAT. Results of the ICC analysis indicated that an average of four successive cycles (mean 4.5 ± 2.7 for 2 Hz; 3.9 ± 2.6 for 2.4 Hz; 3.3 ± 2.7 for 2.8 Hz were necessary to achieve maximum ICC values. Except for jumping period, maximum ICC values took values from 0.592 to 0.991 and all were significantly (p < 0.05 different from zero. Results of the SAT revealed that an average of ten successive cycles (mean 10.5 ± 3.5 for 2 Hz; 9.2 ± 3.8 for 2.4 Hz; 9.0 ± 3.9 for 2.8 Hz were necessary to achieve stability of the selected parameters using criteria previously reported in the literature. Using 10 reference trials, the SAT required standard deviation criterion values of 0.49, 0.41 and 0.55 for 2 Hz, 2.4 Hz and 2.8 Hz jumping rates, respectively, in order to approximate

  16. Sexual practices in Malaysia: determinants of sexual intercourse among unmarried youths.

    Science.gov (United States)

    Zulkifli, S N; Low, W Y

    2000-10-01

    This paper describes findings on selected determinants of sexual intercourse among 468 unmarried adolescents from a survey in Malaysia. Data on respondents' background, sexual experience, contraceptive use, and sexual attitudes are provided. Based on multiple logistic regressions, factors significantly predictive of sexual experience are gender, employment, and sexual attitudes.

  17. Sexual Self-Concept and Sexual Risk-Taking.

    Science.gov (United States)

    Breakwell, Glynis M.; Millward, Lynne J.

    1997-01-01

    Presents data from a survey of randomly selected adolescents (N=474) which examined differences between male and female sexual identities. Results indicate two main dimensions in male sexual self-concept: socioemotional and the relational. Female sexual self-concept revolved around concerns with assertiveness, such as controlling when sex occurs.…

  18. Soil aggregate stability and size-selective sediment transport with surface runoff as affected by organic residue amendment.

    Science.gov (United States)

    Shi, Pu; Arter, Christian; Liu, Xingyu; Keller, Martin; Schulin, Rainer

    2017-12-31

    Aggregate breakdown influences the availability of soil particles for size-selective sediment transport with surface runoff during erosive rainfall events. Organic matter management is known to affect aggregate stability against breakdown, but little is known about how this translates into rainfall-induced aggregate fragmentation and sediment transport under field conditions. In this study, we performed field experiments in which artificial rainfall was applied after pre-wetting on three pairs of arable soil plots (1.5×0.75m) six weeks after incorporating a mixture of grass and wheat straw into the topsoil of one plot in each pair (OI treatment) but not on the other plot (NI treatment). Artificial rainfall was applied for approximately 2h on each pair at an intensity of 49.1mmh -1 . In both treatments, discharge and sediment concentration in the discharge were correlated and followed a similar temporal pattern after the onset of surface runoff: After a sharp increase at the beginning both approached a steady state. But the onset of runoff was more delayed on the OI plots, and the discharge and sediment concentration were in average only roughly half as high on the OI as on the NI plots. With increasing discharge the fraction of coarse sediment increased. This relationship did not differ between the two treatments. Thus, due to the lower discharge, the fraction of fine particles in the exported sediment was larger in the runoff from the OI plots than from the NI plots. The later runoff onset and lower discharge rate was related to a higher initial aggregate stability on the OI plots. Terrestrial laser scanning proved to be a very valuable method to map changes in the micro-topography of the soil surfaces. It revealed a much less profound decrease in surface roughness on the OI than on the NI plots. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Changing folding and binding stability in a viral coat protein: a comparison between substitutions accessible through mutation and those fixed by natural selection.

    Science.gov (United States)

    Miller, Craig R; Lee, Kuo Hao; Wichman, Holly A; Ytreberg, F Marty

    2014-01-01

    Previous studies have shown that most random amino acid substitutions destabilize protein folding (i.e. increase the folding free energy). No analogous studies have been carried out for protein-protein binding. Here we use a structure-based model of the major coat protein in a simple virus, bacteriophage φX174, to estimate the free energy of folding of a single coat protein and binding of five coat proteins within a pentameric unit. We confirm and extend previous work in finding that most accessible substitutions destabilize both protein folding and protein-protein binding. We compare the pool of accessible substitutions with those observed among the φX174-like wild phage and in experimental evolution with φX174. We find that observed substitutions have smaller effects on stability than expected by chance. An analysis of adaptations at high temperatures suggests that selection favors either substitutions with no effect on stability or those that simultaneously stabilize protein folding and slightly destabilize protein binding. We speculate that these mutations might involve adjusting the rate of capsid assembly. At normal laboratory temperature there is little evidence of directional selection. Finally, we show that cumulative changes in stability are highly variable; sometimes they are well beyond the bounds of single substitution changes and sometimes they are not. The variation leads us to conclude that phenotype selection acts on more than just stability. Instances of larger cumulative stability change (never via a single substitution despite their availability) lead us to conclude that selection views stability at a local, not a global, level.

  20. How Setswana Cultural Beliefs and Practices on Sexuality Affect Teachers' and Adolescents' Sexual Decisions, Practices, and Experiences as well as HIV/AIDS and STI Prevention in Select Botswanan Secondary Schools.

    Science.gov (United States)

    Nleya, Paul T; Segale, Emelda

    2015-01-01

    The article reports on the aspects of a Botswana Ministry of Education and Skills Development (MoE & SD) HIV/AIDS Instructional Television (ITV) project modeled on a similar HIV/AIDS program implemented in Brazil. This Teacher Capacity Building Project (TCBP) in Botswana is in its initial years of implementation. Its overall goal is to contribute to the prevention and mitigation of the impact of HIV and AIDS by strengthening the capacity of the education and communication sectors to deliver interactive, distance HIV/AIDS education primarily to teachers so that they act as agents of behavior change among the in-school youth. One of the components of the TCBP program is a live teacher education television HIV/AIDS program called Talk Back program. Talk Back is a collaborative effort of the MoE & SD and the Botswana national television station. The Talk Back program involves development and implementation of weekly 1 hour live HIV/AIDS education interactive TV broadcasts for teachers. The development of the live programs is guided by a curriculum that provides a wide range of themes related to HIV/AIDS and education. This article reports the results of a survey of a sample of teachers and students at junior secondary schools and senior secondary schools, first, on their views and opinions regarding the Talk Back program as a TCBP. Second, how Setswana cultural beliefs, myths, and practices on sexuality affect teachers' and adolescents' sexual decisions, practices, and experiences as well as HIV/AIDS and sexually transmitted infection prevention. A questionnaire survey and focus group interviews were used as data collection instruments in selected secondary schools. The findings of the study suggest that the Talk Back program has not met much success as a TCBP. The findings further suggest that several myths, beliefs, misconceptions, and attitudes about HIV/AIDS exist among Botswana teachers and students and thus make it difficult for the Talk Back program to impart

  1. Stability of selected serum hormones and lipids after long-term storage in the Janus Serum Bank.

    Science.gov (United States)

    Gislefoss, Randi E; Grimsrud, Tom K; Mørkrid, Lars

    2015-04-01

    The potential value of a biobank depends on the quality of the samples, i.e. how well they reflect the biological or biochemical state of the donors at the time of sampling. Documentation of sample quality has become a particularly important issue for researchers and users of biobank studies. The aim of this study was to investigate the long-term stability of selected components: cholesterol, high density cholesterol (HDLC), low density cholesterol (LDLC), apolipoprotein A1 (apo-A1), apolipoprotein B (apo B), follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), thyroid stimulating hormone (TSH) and free thyroxin (FT4). Samples, stored at -25°C, from 520 men aged 40-49 years at blood sampling distributed in equally sized groups (n=130) according to length of storage, 0, 4, 17 and 29 years, respectively, were used in a cross sectional design. The freshly collected serum samples were used as a reference group to calculate storage related changes. The differences between fresh samples and samples stored for 29 years were substantial for apo-A1 (+12%), apo-B (+22.3%), HDLC (-69.2%), LDLC (+31.3%), and PRL (-33.5%), while total cholesterol, FSH, LH, TSH and FT4 did not show any significant difference. The study showed large differences in serum level of the selected components. The lipids and apolipoproteins were all changed except for total cholesterol. Most hormones investigated (FSH, LH, TSH and FT4) proved to be stable after 29 years of storage while PRL showed sign of degradation. The observed differences are probably due to long-term storage effects and/or external factors (i.e. diet and smoking). Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  2. Sexual Health

    Science.gov (United States)

    ... and changes in sexual function are common. These physiological changes can include: A need for more stimulation ... page: Sexuality in later life. National Institute on Aging. https://www.nia.nih.gov/health/publication/sexuality- ...

  3. Sexual Education

    OpenAIRE

    Býmová, Pavlína

    2008-01-01

    The subject matter of this diploma thesis "Sexual Education" is sexual education in the Czech Republic, specifically dedicated to the study of the integration of sexual education into the educational process in schools and families.

  4. Semi-fluorinated sulfonated polyimide membranes with enhanced proton selectivity and stability for vanadium redox flow batteries

    International Nuclear Information System (INIS)

    Li, Jinchao; Liu, Suqin; He, Zhen; Zhou, Zhi

    2016-01-01

    A series of semi-fluorinated sulfonated polyimides (6F-SPIs) are designed and synthesized via a one-step high-temperature polycondensation reaction. The sulfonation degrees of 6F-SPIs are controlled through changing the ratio of sulfonated diamine to non-sulfonated diamine in the casting solution. The physico-chemical properties and single cell performance of 6F-SPI membranes are thoroughly evaluated and compared to a non-fluorinated SPI membrane (6H-SPI-50) and a Nafion 115 membrane. The results show that the designed 6F-SPI membrane with a 50% sulfonation degree (6F-SPI-50) possesses the highest proton selectivity (1.613 × 10 5 S min cm −3 ) among all tested membranes. Besides, the 6F-SPI-50 membrane exhibits a promising performance for vanadium redox flow batteries (VRFBs), showing higher coulombic efficiencies (96.90–99.20%) and energy efficiencies (88.25–64.80%) than the Nafion 115 membrane (with coulombic efficiencies of 90.60–96.70% and energy efficiencies of 81.04–60.10%) at the current densities ranging from 20 to 100 mA cm −2 . Moreover, the 6F-SPI-50 membrane shows excellent chemical stability in the VRFB system. This work paves the way for the development of a new class of 6F-SPI membranes for the VRFB application.

  5. Surface passivation of mixed-halide perovskite CsPb(BrxI1-x)3 nanocrystals by selective etching for improved stability.

    Science.gov (United States)

    Jing, Qiang; Zhang, Mian; Huang, Xiang; Ren, Xiaoming; Wang, Peng; Lu, Zhenda

    2017-06-08

    In recent years, there has been an unprecedented rise in the research of halide perovskites because of their important optoelectronic applications, including photovoltaic cells, light-emitting diodes, photodetectors and lasers. The most pressing question concerns the stability of these materials. Here faster degradation and PL quenching are observed at higher iodine content for mixed-halide perovskite CsPb(Br x I 1-x ) 3 nanocrystals, and a simple yet effective method is reported to significantly enhance their stability. After selective etching with acetone, surface iodine is partially etched away to form a bromine-rich surface passivation layer on mixed-halide perovskite nanocrystals. This passivation layer remarkably stabilizes the nanocrystals, making their PL intensity improved by almost three orders of magnitude. It is expected that a similar passivation layer can also be applied to various other kinds of perovskite materials with poor stability issues.

  6. Dimorfismo sexual en el acebo, Ilex aquifolium: ¿coste de la reproducción, selección sexual o diferenciación fisiológica? Sexual dimorphism in holly Ilex aquifolium: cost of reproduction, sexual selection or physiological differentiation?

    Directory of Open Access Journals (Sweden)

    JOSÉ RAMÓN OBESO

    2002-03-01

    (Aquifoliaceae: cost of reproduction, sexual selection (pollen competition and physiological differentiation between sexes. Here we present both published and new experimental and observational results. At flowering, males allocated more in reproduction than females; however at fruiting females allocated about ten times more in terms of carbon and about five times more in terms of nitrogen than males. Both sexes did not differ in leaf dynamics. Branch RGR usually showed greater values in male branches, but the results depended on the ecological context. Tree growth rate, estimated from mean width of annual rings over 10-30 yr, was significantly higher for males. Experimental debbuding in reproductive branches of females accounted for an increase in RGR compared to branches that matured fruits. When competition among males was examined, there were significant differences among male trees in pollen production per flower. The experimental crossing of five males and five females demonstrated strong maternal effects on fecundity, while non significant differences among males were found in their probability of sire progeny. There were some physiological differences between sexes. The efficiency of photosynthesis of leaves (measured as Fv' / Fm' on nonfruiting branches of females was higher than for leaves on branches of male trees under low-light conditions. On the other side, the water-use efficiency, measured by carbon isotope discrimination, was greater in males under xeric conditions. These results are used to discuss the importance of the above mentioned hypothesis

  7. Assessment of dietary exposure in the French population to 13 selected food colours, preservatives, antioxidants, stabilizers, emulsifiers and sweeteners.

    Science.gov (United States)

    Bemrah, Nawel; Leblanc, Jean-Charles; Volatier, Jean-Luc

    2008-01-01

    The results of French intake estimates for 13 food additives prioritized by the methods proposed in the 2001 Report from the European Commission on Dietary Food Additive Intake in the European Union are reported. These 13 additives were selected using the first and second tiers of the three-tier approach. The first tier was based on theoretical food consumption data and the maximum permitted level of additives. The second tier used real individual food consumption data and the maximum permitted level of additives for the substances which exceeded the acceptable daily intakes (ADI) in the first tier. In the third tier reported in this study, intake estimates were calculated for the 13 additives (colours, preservatives, antioxidants, stabilizers, emulsifiers and sweeteners) according to two modelling assumptions corresponding to two different food habit scenarios (assumption 1: consumers consume foods that may or may not contain food additives, and assumption 2: consumers always consume foods that contain additives) when possible. In this approach, real individual food consumption data and the occurrence/use-level of food additives reported by the food industry were used. Overall, the results of the intake estimates are reassuring for the majority of additives studied since the risk of exceeding the ADI was low, except for nitrites, sulfites and annatto, whose ADIs were exceeded by either children or adult consumers or by both populations under one and/or two modelling assumptions. Under the first assumption, the ADI is exceeded for high consumers among adults for nitrites and sulfites (155 and 118.4%, respectively) and among children for nitrites (275%). Under the second assumption, the average nitrites dietary exposure in children exceeds the ADI (146.7%). For high consumers, adults exceed the nitrite and sulfite ADIs (223 and 156.4%, respectively) and children exceed the nitrite, annatto and sulfite ADIs (416.7, 124.6 and 130.6%, respectively).

  8. [Medical students' sexuality--development and fulfilment of sexual needs].

    Science.gov (United States)

    Müldner-Nieckowski, Łukasz; Klasa, Katarzyna; Sobański, Jerzy A; Rutkowski, Krzysztof; Dembińska, Edyta

    2012-01-01

    Education in human sexual physiology and pathology, as well as own sexual health of medical doctors determines in a large proportion the ability to talk with patients about their sexual disorders. Therefore the authors considered important to collect and assess data regarding sexual health and development of Medical Faculty students. Analysis of selected aspects of psychosexual development and sex life of IVth grade medical students. We applied the self-report Questionnaire of Satisfaction with Sexual Life (KSS2), an instrument created to assess sexual problems in patients treated with group psychotherapy. Medical students filled the questionnaire when attending the courses of Psychopathology of neurotic disorders or Psychotherapy. Analysis of the collected data revealed a relatively high differentiation of the studied group in regard of satisfaction and experiences with sexual life, attitudes towards masturbation, relationships and sexual activity. Regarding some aspects, significant differences between women and men occurred. A set of factors were identified, some of them may negatively influence medical doctor's competencies in the domain of sexual health. These are not having sexual debut or even lack of any erotic experiences and lack of sexual satisfaction. The results indicate a significant prevalence of factors, which may impede students education as well as taking into consideration the sexual issues during the medical interview. Assessment of influence of students' and doctors' own sexuality on their competencies in diagnostics and treatment requires further studies.

  9. Select geotechnical properties of a lime stabilized expansive soil amended with bagasse ash and coconut shell powder

    Science.gov (United States)

    James, Jijo; Pandian, P. Kasinatha

    2018-03-01

    Lime stabilization has been and still is one of the most preferred methods for stabilization of expansive soils. However, in the recent times, utilization of solid waste materials in soil stabilization has gained prominence as an effective means to manage wastes generated from various sources. In this work, an attempt has been made to utilize waste materials from two sources as auxiliary additives to lime in the stabilization of an expansive soil. Bagasse ash (BA), a waste by-product from the sugar industry and Coconut shell powder (CSP), a processed waste obtained from left over coconut shells of oil extraction industry were used as auxiliary additives. An expansive soil obtained from a local field was subjected to chemical, mineral, microstructural and geotechnical characterization in the laboratory and stabilized using 3% lime. The waste materials were subjected to chemical, mineral and microstructural characterization. The stabilization process was amended with four different contents viz. 0.25%, 0.5%, 1% and 2% of BA and CSP separately and the effect of the amendment was studied on the unconfined compressive strength (UCS), plasticity, swell-shrink and microstructural characteristics of the expansive soil. The results of the study indicated that BA amendment of lime stabilization performed better than CSP in improving the UCS, plasticity, swell-shrink and microstructure of the lime stabilized expansive soil.

  10. Select geotechnical properties of a lime stabilized expansive soil amended with bagasse ash and coconut shell powder

    Directory of Open Access Journals (Sweden)

    James Jijo

    2018-03-01

    Full Text Available Lime stabilization has been and still is one of the most preferred methods for stabilization of expansive soils. However, in the recent times, utilization of solid waste materials in soil stabilization has gained prominence as an effective means to manage wastes generated from various sources. In this work, an attempt has been made to utilize waste materials from two sources as auxiliary additives to lime in the stabilization of an expansive soil. Bagasse ash (BA, a waste by-product from the sugar industry and Coconut shell powder (CSP, a processed waste obtained from left over coconut shells of oil extraction industry were used as auxiliary additives. An expansive soil obtained from a local field was subjected to chemical, mineral, microstructural and geotechnical characterization in the laboratory and stabilized using 3% lime. The waste materials were subjected to chemical, mineral and microstructural characterization. The stabilization process was amended with four different contents viz. 0.25%, 0.5%, 1% and 2% of BA and CSP separately and the effect of the amendment was studied on the unconfined compressive strength (UCS, plasticity, swell-shrink and microstructural characteristics of the expansive soil. The results of the study indicated that BA amendment of lime stabilization performed better than CSP in improving the UCS, plasticity, swell-shrink and microstructure of the lime stabilized expansive soil.

  11. Perceived neighborhood partner availability, partner selection, and risk for sexually transmitted infections within a cohort of adolescent females.

    Science.gov (United States)

    Matson, Pamela A; Chung, Shang-En; Ellen, Jonathan M

    2014-07-01

    This research examined the association between a novel measure of perceived partner availability and discordance between ideal and actual partner characteristics as well as trajectories of ideal partner preferences and perceptions of partner availability over time. A clinic-recruited cohort of adolescent females (N = 92), aged 1619 years, were interviewed quarterly for 12 months using audio computer-assisted self-interview. Participants ranked the importance of characteristics for their ideal main sex partner and then reported on these characteristics for their current main partner. Participants reported on perceptions of availability of ideal sex partners in their neighborhood. Paired t-tests examined discordance between ideal and actual partner characteristics. Random-intercept regression models examined repeated measures. Actual partner ratings were lower than ideal partner preferences for fidelity, equaled ideal preferences for emotional support and exceeded ideal preferences for social/economic status and physical attractiveness. Discordance on emotional support and social/economic status was associated with sex partner concurrency. Participants perceived low availability of ideal sex partners. Those who perceived more availability were less likely to be ideal/actual discordant on fidelity [OR = .88, 95% CI: .78, 1.0]. Neither ideal partner preferences nor perceptions of partner availability changed over 12 months. Current main sex partners met or exceeded ideal partner preferences in all domains except fidelity. If emotional needs are met, adolescents may tolerate partner concurrency in areas of limited partner pools. Urban adolescent females who perceive low availability may be at increased risk for sexually transmitted infection (STI) because they may be more likely to have nonmonogamous partners. Copyright © 2014 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  12. Assortative mating and directional or stabilizing selection for a non-linear function of traits in Tribolium.

    Science.gov (United States)

    Campo, J L; Gil, M G

    1993-01-12

    Assortative or random mating following selection in either direction on a non-linear index (experiment 1) or stabilizing selection for pupal length (experiment 2) were carried out for five generations in two lines of Tribolium castaneum (A and R, respectively), with three replicates each. The selected proportion was 25% in all lines. In experiment 1, the selection criterion was designed to increase the aggregate value of adult weight and the first- and second-order powers of pupal length. The A and R lines gave significant responses for the aggregate value (184 ± 6 and 161 ± 14, respectively), pupal length (0.74 ± 0.02 and 0.64 ± 0.05, respectively), and adult weight (0.79 ± 0.03 and 0.78 ± 0.12, respectively). Although the A line was not significantly better than the R line, there was a consistent advantage for assortative mating over random mating, the mean response for aggregate value and pupal length being approximately 1.15 times greater for the A line. In experiment 2 the selection criterion was the square of the deviation from the mean pupal length (stabilizing selection); both lines did not show any change for pupal length. The phenotypic variance showed a significant decrease in the A and R lines, due to a decrease in between-family variance. The assortatively and randomly mated lines were similar for these changes in phenotypic variation. RESUMEN: Aparemiento clasificado y selección direccional o estabilizante para una función no lineal en Tribolium. Dos líneas de Tribolium castaneum fueron seleccionadas direccionalmente para un índice no lineal (experimento 1) o estabilizantemente para longitud de pupa (experimento 2), apareando los animales seleccionados clasificadamente (A) o aleatoriamente (R). Había tres repeticiones por experimento y línea, siendo la proporción de selección el 25%. En el experimento 1, el objetivo de selección incluía el peso adulto así como la longitud de pupa y su cuadrado. Ambas líneas dieron respuesta

  13. The effects of the adjunctive bupropion on male sexual dysfunction induced by a selective serotonin reuptake inhibitor: a double-blind placebo-controlled and randomized study.

    Science.gov (United States)

    Safarinejad, Mohammad Reza

    2010-09-01

    To determine the safety and efficacy of adjunctive bupropion sustained-release (SR) on male sexual dysfunction (SD) induced by a selective serotonin reuptake inhibitor (SSRI), as SD is a common side-effect of SSRIs and the most effective treatments have yet to be determined. The randomized sample consisted of 234 euthymic men who were receiving some type of SSRI. The men were randomly assigned to bupropion SR (150 mg twice daily, 117) or placebo (twice daily, 117) for 12 weeks. Efficacy was evaluated using the Clinical Global Impression-Sexual Function (CGI-SF; the primary outcome measure), the International Index of Erectile Function (IIEF), Arizona Sexual Experience Scale (ASEX), and Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) (secondary outcome measures). Participants were followed biweekly during study period. After 12 weeks of treatment, the mean (sd) scores for CGI-SF were significantly lower, i.e. better, in patients on bupropion SR, at 2.4 (1.2), than in the placebo group, at 3.9 (1.1) (P= 0.01). Men who received bupropion had a significant increase in the total IIEF score (54.4% vs 1.2%; P= 0.003), and in the five different domains of the IIEF. Total ASEX scores were significantly lower, i.e. better, among men who received bupropion than placebo, at 15.5 (4.3) vs 21.5 (4.7) (P= 0.002). The EDITS scores were 67.4 (10.2) for the bupropion and 36.3 (11.7) for the placebo group (P= 0.001). The ASEX score and CGI-SF score were correlated (P= 0.003). In linear regression analyses the CGI-SF score was not affected significantly by the duration of SD, type of SSRI used and age. Bupropion is an effective treatment for male SD induced by SSRIs. These results provide empirical support for conducting a further study of bupropion.

  14. Amelioration of sexual behavior and motor activity deficits in a castrated rodent model with a selective androgen receptor modulator SARM-2f.

    Directory of Open Access Journals (Sweden)

    Megumi Morimoto

    Full Text Available Sarcopenia and cachexia present characteristic features of a decrease in skeletal muscle mass and strength, anorexia, and lack of motivation. Treatments for these diseases have not yet been established, although selective androgen receptor modulators (SARMs are considered as therapeutic targets. We previously reported that a novel SARM compound, SARM-2f, exhibits anabolic effect on muscles, with less stimulatory effect on prostate weight compared with testosterone, in rat Hershberger assays and cancer cachexia models. In this study, we studied the mechanism of action for SARM-2f selectivity and also assessed whether the muscle increase by this compound might lead to improvement of muscle function and physical activity. First, we examined the tissue distribution of SARM-2f. Tissue concentration was 1.2-, 1.6-, and 1.9-fold as high as the plasma concentration in the levator ani muscle, brain, and prostate, respectively. This result showed that the tissue-selective pharmacological effect did not depend on SARM-2f concentration in the tissues. The ability of SARM-2f to influence androgen receptor (AR-mediated transcriptional activation was examined by reporter assays using human normal prostate epithelial cells (PrEC and skeletal muscle cells (SKMC. SARM-2f exerted higher activity against AR in SKMC than in PrEC. Mammalian two hybrid assays showed different co-factor recruitment patterns between SARM-2f and dihydrotestosterone. Next, we studied the effect of SARM-2f on motivation and physical functions such as sexual behavior and motor activities in castrated rat or mouse models. SARM-2f restored the sexual behavior that was lost by castration in male rats. SARM-2f also increased voluntary running distance and locomotor activities. These results suggest that tissue-specific AR regulation by SARM-2f, but not tissue distribution, might account for its tissue specific androgenic effect, and that the muscle mass increase by SARM-2f leads to improvement

  15. Synergistic and alkaline stability studies of mixtures of simulated high level waste sludge with selected energetic compounds

    International Nuclear Information System (INIS)

    Fondeur, F.F.

    2000-01-01

    This study examined the stability of mercury oxalate and mercury fulminate in alkaline sludge simulating Savannah River Site waste. These compounds represent two classes of energetic compounds previously speculated as potential components in sludge stored without a supernatant liquid

  16. Association of Stability Parameters and Yield Stability of Sesame ...

    African Journals Online (AJOL)

    Association of Stability Parameters and Yield Stability of Sesame ( Sesamum ... Information on phenotypic stability is useful for the selection of crop varieties as well as for ... as an alternative to parametric stability measurements is important.

  17. Selection of suitable prodrug candidates for in vivo studies via in vitro studies; the correlation of prodrug stability in between cell culture homogenates and human tissue homogenates.

    Science.gov (United States)

    Tsume, Yasuhiro; Amidon, Gordon L

    2012-01-01

    To determine the correlations/discrepancies of drug stabilities between in the homogenates of human culture cells and of human tissues. Amino acid/dipeptide monoester prodrugs of floxuridine were chosen as the model drugs. The stabilities (half-lives) of floxuridine prodrugs in human tissues (pancreas, liver, and small intestine) homogenates were obtained and compared with ones in cell culture homogenates (AcPC-1, Capan-2, and Caco-2 cells) as well as human liver microsomes. The correlations of prodrug stability in human small bowel tissue homogenate vs. Caco-2 cell homogenate, human liver tissue homogenate vs. human liver microsomes, and human pancreatic tissue homogenate vs. pancreatic cell, AsPC-1 and Capan-2, homogenates were examined. The stabilities of floxuridine prodrugs in human small bowel homogenate exhibited the great correlation to ones in Caco-2 cell homogenate (slope = 1.0-1.3, r2 = 0.79-0.98). The stability of those prodrugs in human pancreas tissue homogenate also exhibited the good correlations to ones in AsPC-1 and Capan-2 cells homogenates (slope = 0.5-0.8, r2 = 0.58-0.79). However, the correlations of prodrug stabilities between in human liver tissue homogenates and in human liver microsomes were weaker than others (slope = 1.3-1.9, r2 = 0.07-0.24). The correlations of drug stabilities in cultured cell homogenates and in human tissue homogenates were compared. Those results exhibited wide range of correlations between in cell homogenate and in human tissue homogenate (r2 = 0.07 - 0.98). Those in vitro studies in cell homogenates would be good tools to predict drug stabilities in vivo and to select drug candidates for further developments. In the series of experiments, 5'-O-D-valyl-floxuridine and 5'-O-L-phenylalanyl-L-tyrosyl-floxuridine would be selected as candidates of oral drug targeting delivery for cancer chemotherapy due to their relatively good stabilities compared to other tested prodrugs.

  18. Promotion Effect of Alkali Metal Hydroxides on Polymer-Stabilized Pd Nanoparticles for Selective Hydrogenation of C–C Triple Bonds in Alkynols

    OpenAIRE

    Nikoshvili, Linda Zh.; Bykov, Alexey V.; Khudyakova, Tatiana E.; Lagrange, Thomas; Héroguel, Florent; Luterbacher, Jeremy S.; Matveeva, Valentina G.; Sulman, Esther M.; Dyson, Paul J.; Kiwi-Minsker, Lioubov

    2017-01-01

    Postimpregnation of Pd nanoparticles (NPs) stabilized within hyper-cross-linked polystyrene with sodium or potassium hydroxides of optimal concentration was found to significantly increase the catalytic activity for the partial hydrogenation of the C–C triple bond in 2-methyl-3-butyn-2-ol at ambient hydrogen pressure. The alkali metal hydroxide accelerates the transformation of the residual Pd(II) salt into Pd(0) NPs and diminishes the reaction induction period. In addition, the selectivity t...

  19. Design aspects of the Alpha Repository. I. Preliminary results of facility layout, room stability, and equipment selection efforts. Summary progress report RSI-0024

    International Nuclear Information System (INIS)

    Gnirk, P.F.; Grams, W.H.; Zeller, T.J.; Ellis, D.B.; Pariseau, W.G.; Fossum, A.F.; Ratigan, J.L.; Hansen, F.D.

    1975-01-01

    Results of preliminary analysis of the stability of mines in salt formations underlying Eddy and Lea Counties in New Mexico are presented. Methods and equipment for drilling canister emplacement holes in these formations were evaluated along with methods for excavating storage areas and transport of the excavated salt. Progress during the period is reported in chapters on geological and rock properties at the repository site, preliminary mine layout, basic requirements for repository usage, excavation geometries, drill selection, excavation systems, and safety requirements

  20. Selectivity and stability of new herbicides and herbicide combinations for the seed yields of some field crops I. Effect at Coriander (Coriandrum Sativum L.)

    OpenAIRE

    G. Delchev

    2016-01-01

    Abstract. . The research was conducted during 2013 – 2015 on pellic vertisol soil type. Under investigation was Bulgarian coriander cultivar Lozen 1 (Coriandrum sativum L.). The purpose of the investigation was to establish the selectivity and stability of some herbicides, herbicide combinations and herbicide tank mixtures on the coriander. Factor A included the years of investigation. Factor B included no treated check, 6 soil-applied herbicides – Tendar EC, Silba SC, Sharpen 33 EC,...

  1. Sexual Essays

    DEFF Research Database (Denmark)

    Giles, James

    Through a series of interrelated essays, this book explores fundamental issues concerning gender, sexual and romantic attraction, sexual desire and fantasies, the sexual positions, age dysphoria, and the role of naked skin in human sexuality. It does so by exploring experiential, social, biological...... on sex. It is further argued that sexual desire is an existential need based on the experience of having a gendered body. A case study of age dysphoria is presented showing how the conclusions concerning concerning gender and desire apply in an atypical case. The body's fundamental role in sexuality......, and evolutionary aspects of sexual life. The author criticizes several popular views, rejecting both social constructionist accounts of gender and social constructionist and biological accounts of sexual desire. It is argued instead that gender roles and gender are often confused and that gender itself is based...

  2. Sexual Health

    Science.gov (United States)

    ... protect yourself from sexually transmitted infections. Talking to kids about sex Kids and sexuality — those words strike fear into the hearts of many parents. But talking to kids about sex is an important part of parenting. Children and ...

  3. Sexual Violence

    Science.gov (United States)

    Sexual Violence Facts at a Glance 2012 Adults In a nationally representative survey of adults: 1 • Nearly 1 in ... 5.6% and 5.3%, respectively) experienced sexual violence other than rape, such as being made to ...

  4. Sex differences in aggression among children of low and high gender inequality backgrounds: a comparison of gender role and sexual selection theories.

    Science.gov (United States)

    Nivette, Amy E; Eisner, Manuel; Malti, Tina; Ribeaud, Denis

    2014-01-01

    It is well understood in aggression research that males tend to exhibit higher levels of physical aggression than females. Yet there are still a number of gaps in our understanding of variation in sex differences in children's aggression, particularly in contexts outside North America. A key assumption of social role theory is that sex differences vary according to gender polarization, whereas sexual selection theory accords variation to the ecological environment that consequently affects male competition [Archer, J. (2009). Behavioral and Brain Sciences, 32, 249-311; Kenrick, D., & Griskevicious, V. (2009). More holes in social roles [Comment]. Behavioral and Brain Sciences, 32, 283-285]. In the present paper, we explore these contradicting theoretical frameworks by examining data from a longitudinal study of a culturally diverse sample of 863 children at ages 7-13 in Zurich, Switzerland. Making use of the large proportion of children from highly diverse immigrant background we compare the size of the sex difference in aggression between children whose parents were born in countries with low and with high levels of gender inequality. The results show that sex differences in aggression are generally larger among children with parents from high gender inequality backgrounds. However, this effect is small in comparison to the direct effect of a child's biological sex. We discuss implications for future research on sex differences in children's aggression. © 2014 Wiley Periodicals, Inc.

  5. The Role of Bioacoustic Signals in Koala Sexual Selection: Insights from Seasonal Patterns of Associations Revealed with GPS-Proximity Units.

    Directory of Open Access Journals (Sweden)

    William Ellis

    Full Text Available Despite being a charismatic and well-known species, the social system of the koala (Phascolarctos cinereus--the only extant member of the family Phascolarctidae is poorly known and much of the koala's sociality and mating behaviors remain un-quantified. We evaluated these using proximity logging-GPS enabled tracking collars on wild koalas and discuss their implications for the mating system of this species. The frequency and duration of male-female encounters increased during the breeding season, with male-male encounters quite uncommon, suggesting little direct mating competition. By comparison, female-female interactions were very common across both seasons. Body mass of males was not correlated with their interactions with females during the breeding season, although male size is associated with a variety of acoustic parameters indicating individuality. We hypothesise that vocal advertising reduces the likelihood of male-male encounters in the breeding season while increasing the rate of male-female encounters. We suggest that male mating-season bellows function to reduce physical confrontations with other males allowing them to space themselves apart, while, at the same time, attracting females. We conclude that indirect male-male competition, female mate choice, and possibly female competition, mediate sexual selection in koalas.

  6. The Role of Bioacoustic Signals in Koala Sexual Selection: Insights from Seasonal Patterns of Associations Revealed with GPS-Proximity Units

    Science.gov (United States)

    Whipple, Bill; Barth, Ben; Johnston, Stephen; Seddon, Jenny; Melzer, Alistair; Higgins, Damien

    2015-01-01

    Despite being a charismatic and well-known species, the social system of the koala (Phascolarctos cinereus—the only extant member of the family Phascolarctidae) is poorly known and much of the koala’s sociality and mating behaviors remain un-quantified. We evaluated these using proximity logging-GPS enabled tracking collars on wild koalas and discuss their implications for the mating system of this species. The frequency and duration of male-female encounters increased during the breeding season, with male-male encounters quite uncommon, suggesting little direct mating competition. By comparison, female-female interactions were very common across both seasons. Body mass of males was not correlated with their interactions with females during the breeding season, although male size is associated with a variety of acoustic parameters indicating individuality. We hypothesise that vocal advertising reduces the likelihood of male-male encounters in the breeding season while increasing the rate of male-female encounters. We suggest that male mating-season bellows function to reduce physical confrontations with other males allowing them to space themselves apart, while, at the same time, attracting females. We conclude that indirect male-male competition, female mate choice, and possibly female competition, mediate sexual selection in koalas. PMID:26154295

  7. Female sexuality

    OpenAIRE

    Rao, T.S. Sathyanarana; Nagaraj, Anil Kumar M.

    2015-01-01

    Sex is a motive force bringing a man and a woman into intimate contact. Sexuality is a central aspect of being human throughout life and encompasses sex, gender identities and roles, sexual orientation, eroticism, pleasure, intimacy, and reproduction. Sexuality is experienced and expressed in thoughts, fantasies, desires, beliefs, attitudes, values, behaviors, practices, roles and relationships. Though generally, women are sexually active during adolescence, they reach their peak orgasmic fre...

  8. Sexual Regret

    Directory of Open Access Journals (Sweden)

    Leif Edward Ottesen Kennair

    2016-12-01

    Full Text Available The current study sought to answer three key questions about explaining the emotion of regret in the domain of casual sex: Are sex differences in sexual regret robust or attenuated in a highly egalitarian culture? What proximate psychological variables might explain sex differences in sexual regret? And what accounts for within-sex variation in experiences of sexual regret about casual sex. We conducted a study of 263 Norwegian students (ages 19–37 who reported how much they regretted having either engaged in, or passed up, their most recent casual sexual experience. Sex differences in sexual regret are not attenuated in this sexually egalitarian culture. The study revealed sex differences in worries about pregnancy, STIs, and reputation; however, these predictors did not succeed in accounting for the sex differences in regret engaging in casual sex. Sexual gratification and socio-sexual orientation both predicted the sex differences in casual sex regret. In contrast, only socio-sexual orientation attenuated the sex difference in regret passing up casual sex. Predictors of within-sex variation in casual sexual regret included worry about sexual reputation, experienced gratification during the encounter, and socio-sexual orientation. Discussion focuses on implications for the psychological design features of this relatively neglected emotion.

  9. Infantile sexuality

    DEFF Research Database (Denmark)

    Zeuthen, Katrine Egede; Gammelgård, Judy

    2010-01-01

    When first presented, Freud´s theory of infantile sexuality was a scandal. Not only was the claim that the small child sucking at the mother´s breast experiences a kind of pleasure that Freud without hesitation named sexual, the theory also turned the common understanding of human sexuality up-si...

  10. Sexual side effects of serotonergic antidepressants: mediated by inhibition of serotonin on central dopamine release?

    Science.gov (United States)

    Bijlsma, Elisabeth Y; Chan, Johnny S W; Olivier, Berend; Veening, Jan G; Millan, Mark J; Waldinger, Marcel D; Oosting, Ronald S

    2014-06-01

    Antidepressant-induced sexual dysfunction adversely affects the quality of life of antidepressant users and reduces compliance with treatment. Animal models provide an instructive approach for examining potential sexual side effects of novel drugs. This review discusses the stability and reproducibility of our standardized test procedure that assesses the acute, subchronic and chronic effects of psychoactive compounds in a 30 minute mating test. In addition, we present an overview of the effects of several different (putative) antidepressants on male rat sexual behavior, as tested in our standardized test procedure. By comparing the effects of these mechanistically distinct antidepressants (paroxetine, venlafaxine, bupropion, buspirone, DOV 216,303 and S32006), this review discusses the putative mechanism underlying sexual side effects of antidepressants and their normalization. This review shows that sexual behavior is mainly inhibited by antidepressants that increase serotonin neurotransmission via blockade of serotonin transporters, while those that mainly increase the levels of dopamine and noradrenaline are devoid of sexual side effects. Those sexual disturbances cannot be normalized by simultaneously increasing noradrenaline neurotransmission, but are normalized by increasing both noradrenaline and dopamine neurotransmission. Therefore, it is hypothesized that the sexual side effects of selective serotonin reuptake inhibitors may be mediated by their inhibitory effects on dopamine signaling in sex brain circuits. Clinical development of novel antidepressants should therefore focus on compounds that simultaneously increase both serotonin and dopamine signaling. © 2013 Elsevier Inc. All rights reserved.

  11. Using artificial neural networks to select upright cowpea (Vigna unguiculata) genotypes with high productivity and phenotypic stability.

    Science.gov (United States)

    Barroso, L M A; Teodoro, P E; Nascimento, M; Torres, F E; Nascimento, A C C; Azevedo, C F; Teixeira, F R F

    2016-11-03

    Cowpea (Vigna unguiculata) is grown in three Brazilian regions: the Midwest, North, and Northeast, and is consumed by people on low incomes. It is important to investigate the genotype x environment (GE) interaction to provide accurate recommendations for farmers. The aim of this study was to identify cowpea genotypes with high adaptability and phenotypic stability for growing in the Brazilian Cerrado, and to compare the use of artificial neural networks with the Eberhart and Russell (1966) method. Six trials with upright cowpea genotypes were conducted in 2005 and 2006 in the States of Mato Grosso do Sul and Mato Grosso. The data were subjected to adaptability and stability analysis by the Eberhart and Russell (1966) method and artificial neural networks. The genotypes MNC99-537F-4 and EVX91-2E-2 provided grain yields above the overall environment means, and exhibited high stability according to both methods. Genotype IT93K-93-10 was the most suitable for unfavorable environments. There was a high correlation between the results of both methods in terms of classifying the genotypes by their adaptability and stability. Therefore, this new approach would be effective in quantifying the GE interaction in upright cowpea breeding programs.

  12. The Effect of Preanalytical Factors on Stability of the Proteome and Selected Metabolites in Cerebrospinal Fluid (CSF)

    NARCIS (Netherlands)

    Rosenling, T.; Slim, C.L.; Christin, C.; Coulier, L.; Shi, S.; Stoop, M.P.; Bosman, J.; Suits, F.; Horvatovich, P.L.; Stockhofe, N.; Vreeken, R.; Hankemeier, T.; Gool, A.J.; Luider, T.M.; Bischoff, R.

    2009-01-01

    To standardize the use of cerebrospinal fluid (CSF) for biomarker research, a set of stability studies have been performed on porcine samples to investigate the influence of common sample handling procedures on proteins, peptides, metabolites and free amino acids. This study focuses at the effect on

  13. The effect of preanalytical factors on stability of the proteome and selected metabolites in Cerebrospinal Fluid (CSF)

    NARCIS (Netherlands)

    Rosenling, T.; Slim, C.L.; Christin, C.; Coulier, L.; Shi, S.; Stoop, M.P.; Bosman, J.; Suits, F.; Horvatovich, P.L.; Stockhofe-Zurwieden, N.; Vreeken, R.; Hankemeier, T.; Gool, A.J. van; Luider, T.M.; Bischoff, R.

    2009-01-01

    To standardize the use of cerebrospinal fluid (CSF) for biomarker research, a set of stability studies have been performed on porcine samples to investigate the influence of common sample handling procedures on proteins, peptides, metabolites and free amino acids. This study focuses at the effect on

  14. The effect of pre-analytical factors on stability of the proteome and selected metabolites in cerebrospinal fluid (CSF)

    NARCIS (Netherlands)

    Rosenling, T.; Slim, Christiaan Lucas; Christin, C.; Coulier, L.; Bosman, J; Shi, S.; Suits, F.; Stockhofe-Zurwieden, N.; Vreeken, R.; Hankemeier, T; Gool, A.; Luider, T.; Bischoff, Rainer

    2009-01-01

    In order to standardize the use of cerebrospinal fluid (CSF) for biomarker research, a set of stability studies have been performed on porcine samples to investigate the influence of common sample handling procedures on proteins, peptides, metabolites and free amino acids. This study focuses at the

  15. Expression stability and selection of optimal reference genes for gene expression normalization in early life stage rainbow trout exposed to cadmium and copper.

    Science.gov (United States)

    Shekh, Kamran; Tang, Song; Niyogi, Som; Hecker, Markus

    2017-09-01

    Gene expression analysis represents a powerful approach to characterize the specific mechanisms by which contaminants interact with organisms. One of the key considerations when conducting gene expression analyses using quantitative real-time reverse transcription-polymerase chain reaction (qPCR) is the selection of appropriate reference genes, which is often overlooked. Specifically, to reach meaningful conclusions when using relative quantification approaches, expression levels of reference genes must be highly stable and cannot vary as a function of experimental conditions. However, to date, information on the stability of commonly used reference genes across developmental stages, tissues and after exposure to contaminants such as metals is lacking for many vertebrate species including teleost fish. Therefore, in this study, we assessed the stability of expression of 8 reference gene candidates in the gills and skin of three different early life-stages of rainbow trout after acute exposure (24h) to two metals, cadmium (Cd) and copper (Cu) using qPCR. Candidate housekeeping genes were: beta actin (b-actin), DNA directed RNA polymerase II subunit I (DRP2), elongation factor-1 alpha (EF1a), glyceraldehyde 3-phosphate dehydrogenase (GAPDH), glucose-6-phosphate dehydrogenase (G6PD), hypoxanthine phosphoribosyltransferase (HPRT), ribosomal protein L8 (RPL8), and 18S ribosomal RNA (18S). Four algorithms, geNorm, NormFinder, BestKeeper, and the comparative ΔCt method were employed to systematically evaluate the expression stability of these candidate genes under control and exposed conditions as well as across three different life-stages. Finally, stability of genes was ranked by taking geometric means of the ranks established by the different methods. Stability of reference genes was ranked in the following order (from lower to higher stability): HPRT

  16. Influence of ERβ selective agonism during the neonatal period on the sexual differentiation of the rat hypothalamic-pituitary-gonadal (HPG axis

    Directory of Open Access Journals (Sweden)

    Patisaul Heather B

    2012-01-01

    Full Text Available Abstract Background It is well established that sexual differentiation of the rodent hypothalamic-pituitary-gonadal (HPG axis is principally orchestrated by estrogen during the perinatal period. Here we sought to better characterize the mechanistic role the beta form of the estrogen receptor (ERβ plays in this process. Methods To achieve this, we exposed neonatal female rats to three doses (0.5, 1 and 2 mg/kg of the ERβ selective agonist diarylpropionitrile (DPN using estradiol benzoate (EB as a positive control. Measures included day of vaginal opening, estrous cycle quality, GnRH and Fos co-localization following ovariectomy and hormone priming, circulating luteinizing hormone (LH levels and quantification of hypothalamic kisspeptin immunoreactivity. A second set of females was then neonatally exposed to DPN, the ERα agonist propyl-pyrazole-triol (PPT, DPN+PPT, or EB to compare the impact of ERα and ERβ selective agonism on kisspeptin gene expression in pre- and post-pubescent females. Results All three DPN doses significantly advanced the day of vaginal opening and induced premature anestrus. GnRH and Fos co-labeling, a marker of GnRH activation, following ovariectomy and hormone priming was reduced by approximately half at all doses; the magnitude of which was not as large as with EB or what we have previously observed with the ERα agonist PPT. LH levels were also correspondingly lower, compared to control females. No impact of DPN was observed on the density of kisspeptin immunoreactive (-ir fibers or cell bodies in the arcuate (ARC nucleus, and kisspeptin-ir was only significantly reduced by the middle (1 mg/kg DPN dose in the preoptic region. The second experiment revealed that EB, PPT and the combination of DPN+PPT significantly abrogated preoptic Kiss1 expression at both ages but ARC expression was only reduced by EB. Conclusion Our results indicate that selective agonism of ERβ is not sufficient to completely achieve male

  17. Sexual Health

    Directory of Open Access Journals (Sweden)

    McMahon Sharon

    2004-08-01

    Full Text Available Abstract Health Issue Much attention is devoted to women's reproductive health, but the formative and mature stages of women's sexual lives are often overlooked. We have analyzed cross-sectional data from the Sexual Behaviour module of the 2000/2001 Canadian Community Health Survey (CCHS, and reviewed the literature and available indicators of the sexual health of Canadian women. Key Findings Contemporary Canadian adolescents are becoming sexually active at younger ages than in previous generations. The gender gap between young males and females in age at first intercourse has virtually disappeared. The mean age at first intercourse for CCHS respondents aged 15–24 years was between 16 and 17. Canadian-born respondents are significantly younger at first intercourse than those who were born outside of Canada. Few adolescents recognize important risks to their sexual health. Older Canadians are sexually active, and continue to find emotional and physical satisfaction in their sexual relationships. Data Gaps and Recommendations Both health surveys and targeted research must employ a broader understanding of sexuality to measure changes in and determinants of the sexual health of Canadians. There is reluctance to direct questions about sexual issues to younger Canadians, even though increased knowledge of sexual health topics is associated with delayed onset of sexual intercourse. Among adults, sex-positive resources are needed to address aspects of aging, rather than medicalizing age-related sexual dysfunction. Age and gender-appropriate sexual health care, education, and knowledge are important not only for women of reproductive age, but for Canadians at all stages of life.

  18. Glucocorticoids selectively inhibit the transcription of the interleukin 1β gene and decrease the stability of interleukin 1β mRNA

    International Nuclear Information System (INIS)

    Lee, S.W.; Tsou, A.P.; Chan, H.; Thomas, J.; Petrie, K.; Eugui, E.M.; Allison, A.C.

    1988-01-01

    Transcription of the interleukin 1β (IL-1β) gene was studied by mRNA hybridization with a cDNA probe in the human promonocytic cell line U-937. Phorbol ester and lipopolysaccharide increased the steady-state level of Il-1β mRNA. Glucocorticoids markedly decreased IL-1β mRNA levels by two mechanisms. Transcription of the IL-1 gene was inhibited, as shown by in vitro transcription assays with nuclei isolated from glucocorticoid-treated cells. Moreover, kinetic analyses and pulse-labeling of mRNAs showed that glucocorticoids selectively decrease the stability of IL-1β mRNA, without affecting the stability of β-actin and FOS mRNAs. Inhibition of the formation and effects IL-1 is a mechanism by which glucocorticoids can exert antiinflammatory and immunosuppressive effects

  19. Freshman Sexual Attitudes and Behavior.

    Science.gov (United States)

    Nutt, Roberta L.; Sedlacek, William E.

    At the University of Maryland, 758 randomly selected incoming freshman students were administered an anonymous poll regarding their sexual attitudes and behavior. Results showed that the Maryland freshman generally resembled other U.S. college students in their sexual experience. Approximately half (52% of males, 46% of females) reported that they…

  20. The film thickness dependent thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Xiudi; Xu Gang, E-mail: xiudixiao@163.com; Xiong Bin; Chen Deming; Miao Lei [Chinese Academy of Sciences, Key Laboratory of Renewable Energy and Gas Hydrates, Guangzhou Institute of Energy Conversion (China)

    2012-03-15

    The monolayer Al{sub 2}O{sub 3}:Ag thin films were prepared by magnetron sputtering. The microstructure and optical properties of thin film after annealing at 700 Degree-Sign C in air were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and spectrophotometer. It revealed that the particle shape, size, and distribution across the film were greatly changed before and after annealing. The surface plasmon resonance absorption and thermal stability of the film were found to be strongly dependent on the film thickness, which was believed to be associated with the evolution process of particle diffusion, agglomeration, and evaporation during annealing at high temperature. When the film thickness was smaller than 90 nm, the film SPR absorption can be attenuated until extinct with increasing annealing time due to the evaporation of Ag particles. While the film thickness was larger than 120 nm, the absorption can keep constant even after annealing for 64 h due to the agglomeration of Ag particles. On the base of film thickness results, the multilayer Al{sub 2}O{sub 3}:Ag solar selective thin films were prepared and the thermal stability test illustrated that the solar selectivity of multilayer films with absorbing layer thickness larger than 120 nm did not degrade after annealing at 500 Degree-Sign C for 70 h in air. It can be concluded that film thickness is an important factor to control the thermal stability of Al{sub 2}O{sub 3}:Ag thin films as high-temperature solar selective absorbers.

  1. Friendship, sexual intimacy and young people's negotiations of sexual health.

    Science.gov (United States)

    Byron, Paul

    2017-04-01

    This paper examines how young people's friendships influence safer sexual practices. Through a thematic discourse analysis, interviews with Sydney-based young people (aged 18-25 years) and Australian-based sexual health websites for young people are considered. Interview data illustrate how friendships can support young people's sexual experiences, concerns and safeties beyond the practice of 'safe sex' (condom use). This is evident in friends' practices of sex and relationship advice, open dialogue, trust and sharing experiential knowledge, as well as friend-based sex. Meanwhile, friendship discourse from selected Australian sexual health websites fails to engage with the support offered by friendship, or its value to a sexual health agenda. Foucault's account of friendship as a space of self-invention is considered in light of these data, along with his argument that friendship poses a threat to formal systems of knowing and regulating sex. Whether sexual or not, many close friendships are sexually intimate given the knowledge, support and influence these offer to one's sexual practices and relations. This paper argues that greater attention to friendship among sexual health promoters and researchers would improve professional engagements with young people's contemporary sexual cultures, and better inform their attempts to engage young people through social media.

  2. Molecular Basis of Inactive B-RAF(WT) and B-RAF(V600E) Ligand Inhibition, Selectivity and Conformational Stability: An in Silico Study

    DEFF Research Database (Denmark)

    Fratev, Filip Filipov; Jonsdottir, Svava Osk; Mihaylova, E.

    2009-01-01

    -PBSA and local-binding energy (LBE) approaches. The conformational stability of the unbounded kinases and in particular the processes of the B-RAF(V600E) mutant activation were analyzed. A unique salt bridge network formed mainly by the catalytic residues was identified in the unbounded B...... effects on B-RAF(V600E) was revealed, which can explain the low mutant selectivity observed for numerous inhibitors. Our results suggest that the interactions between the activation segment and the alpha C-helix, as well as between the residues in the salt bridge network, are the major mechanism of the B...

  3. Sexual harassment.

    Science.gov (United States)

    Sbraga, T P; O'Donohue, W

    2000-01-01

    We review the current state of sexual harassment theory, research, treatment, and prevention. Definitional problems and implications are discussed. An examination of the epidemiology of sexual harassment is presented, highlighting correlates that include characteristics of the organizational environment, the perpetrator, and the recipient of unwanted sexual behavior. Normative responses to sexual harassment and consequences are discussed. Descriptions of the most prevalent models of sexual harassment are offered and the empirical evidence for them is briefly reviewed. From there, the effect of model development and evaluation on the prevention and treatment of sexual harassment is considered. We comment on the steps that would need to be taken to develop viable prevention and treatment programs. Suggestions for fruitful avenues of research and theory development are offered.

  4. A comparative study between three stability indicating spectrophotometric methods for the determination of diatrizoate sodium in presence of its cytotoxic degradation product based on two-wavelength selection

    Science.gov (United States)

    Riad, Safaa M.; El-Rahman, Mohamed K. Abd; Fawaz, Esraa M.; Shehata, Mostafa A.

    2015-06-01

    Three sensitive, selective, and precise stability indicating spectrophotometric methods for the determination of the X-ray contrast agent, diatrizoate sodium (DTA) in the presence of its acidic degradation product (highly cytotoxic 3,5-diamino metabolite) and in pharmaceutical formulation, were developed and validated. The first method is ratio difference, the second one is the bivariate method, and the third one is the dual wavelength method. The calibration curves for the three proposed methods are linear over a concentration range of 2-24 μg/mL. The selectivity of the proposed methods was tested using laboratory prepared mixtures. The proposed methods have been successfully applied to the analysis of DTA in pharmaceutical dosage forms without interference from other dosage form additives. The results were statistically compared with the official US pharmacopeial method. No significant difference for either accuracy or precision was observed.

  5. Enhanced hydrothermal stability of Cu-ZSM-5 catalyst via surface modification in the selective catalytic reduction of NO with NH_3

    International Nuclear Information System (INIS)

    Zhang, Tao; Shi, Juan; Liu, Jian; Wang, Daxi; Zhao, Zhen; Cheng, Kai; Li, Jianmei

    2016-01-01

    Highlights: • The hydrothermal stability of Cu-ZSM-5 catalyst was enhanced after surface modification. • An inert silica layer was deposited on the surface of Cu-ZSM-5 and formed a protective layer. • The contact between Si and Cu and Al atoms could form Si-O-Al and Si- O−Cu bonds. • The redox and acidity properties of Cu-ZSM-5-CLD-Aged catalyst were largely retained. • The adsorption and activation of NO and NH_3 was almost unchanged over Cu-ZSM-5-CLD catalyst before and after hydrothermal treatment. - Abstract: The surface of Cu-ZSM-5 catalyst was modified by chemical liquid deposition (CLD) of tetraethoxysilane (TEOS) for enhancing its hydrothermal stability in the selective catalytic reduction of NO with NH_3. After hydrothermal aging at 750 °C for 13 h, the catalytic performance of Cu-ZSM-5-Aged catalyst was significantly reduced for NO reduction in the entire temperature range, while that of Cu-ZSM-5-CLD-Aged catalyst was affected very little. The characterization results indicated that an inert silica layer was deposited on the surface of Cu-ZSM-5 and formed a protective layer, which prevents the detachment of Cu"2"+ from ZSM-5 ion-exchange positions and the dealumination of zeolite during the hydrothermal aging process. Based on the data it is hypothesized to be the primary reason for the high hydrothermal stability of Cu-ZSM-5-CLD catalyst.

  6. Male sexuality.

    Science.gov (United States)

    Ginsberg, Terrie B

    2010-05-01

    It should be recognized that sexuality in the aging male is of such import that a complete sexual history must be performed. By taking a complete sexual history, facts can be obtained that will allow for appropriate focus relating to a holistic evaluation and will enable us to dispel antiquated sexual myths pertaining to the aging male. If initiated by the history taker, questions concerning sexuality may be discussed more comfortably by the patient. Erectile dysfunction, male sexual response cycle, testosterone, sexually transmitted diseases, human immunodeficiency virus, long-term illness, along with religion and culture are explored in this article with the aim of improving one's knowledge base, self reflection, and awareness of the importance of male sexuality. A complete understanding and appreciation of the aging male's medical history, surgical history, social history, and emotional history as well as his sexual, cultural, and religious concepts will allow the health care provider to better analyze information, and to recommend and provide appropriate advice and treatment to the aging male patient. Copyright 2010 Elsevier Inc. All rights reserved.

  7. Sexual pain.

    Science.gov (United States)

    Boardman, Lori A; Stockdale, Colleen K

    2009-12-01

    Sexual pain is an underrecognized and poorly treated constellation of disorders that significantly impact affected women and their partners. Recognized as a form of chronic pain, sexual pain disorders are heterogeneous and include dyspareunia (superficial and deep), vaginismus, vulvodynia, vestibulitis, and noncoital sexual pain disorder. Women too often tolerate pain in the belief that this will meet their partners' needs. This article provides a review of the terminology and definition of the condition, theories on the pathophysiology, diagnostic considerations, and recommendations on the management of female sexual pain.

  8. Sexual addictions.

    Science.gov (United States)

    Garcia, Frederico Duarte; Thibaut, Florence

    2010-09-01

    The potential adverse consequences, personal distress, shame and guilt presented by patients who suffer from sexual addiction require a more in-depth understanding of the phenomenology and psychobiology of this disorder. A bibliographic review was conducted using MEDLINE and EBSCO databases with the following keywords: "sexual addiction," "hypersexuality," "compulsive sexual behavior," "behavioural addiction," "treatment," and "addiction." Several conceptualizations of excessive nonparaphilic sexual disorder have been proposed based on the models of, respectively, obsessive compulsive disorder, impulse control disorder, out of control excessive sexual disorder, and addictive disorder. Despite the lack of robust scientific data, a number of clinical elements, such as the frequent preoccupation with this type of behavior, the time spent in sexual activities, the continuation of this behavior despite its negative consequences, the repeated and unsuccessful efforts made to reduce the behavior, are in favor of an addictive disorder. In addition there is a high comorbidity between excessive sexual behavior and other addictive behaviors. The phenomenology of excessive nonparaphilic sexual disorder favors its conceptualization as an addictive behavior, rather than an obsessive-compulsive, or an impulse control disorder. Moreover, the criteria that are quite close to those of addictive disorders were recently proposed for the future DSM-V in order to improve the characterization of this condition. Finally, controlled studies are warranted in order to establish clear guidelines for treatment of sexual addiction.

  9. Internet Sexualities

    Science.gov (United States)

    Döring, Nicola

    The term “internet sexuality” (or OSA, online sexual activities) refers to sexual-related content and activities observable on the internet (cf. Adams, Oye, & Parker, 2003; Cooper, McLoughlin, & Campbell, 2000; Leiblum & Döring, 2002). It designates a variety of sexual phenomena (e.g., pornography, sex education, sexual contacts) related to a wide spectrum of online services and applications (e.g., websites, online chat rooms, peer-to-peer networks). If an even broader range of computer networks - such as the Usenet or bulletin board systems - is included in this extensional definition, one speaks of “online sexuality” or “cybersexuality.”

  10. Isothermal Stability and Selected Mechanical Properties of Zr48Cu36Al8Ag8 Bulk Metallic Glass

    Directory of Open Access Journals (Sweden)

    Błyskun P.

    2017-09-01

    Full Text Available The aim of this work was to investigate the influence of isothermal annealing on the amorphous structure stability of the Zr48Cu36Al8Ag8 alloy. A series of continuous heating examinations was performed on the differential scanning calorimeter in order to determine the temperature limits for isothermal annealing series where the time to crystallization was measured. The obtained results were calculated and a time-temperature-transformation diagram was created and discussed. Static compression test as well as microhardness measurements of the as-quenched samples gave a mechanical properties results supplement. The measured properties (σc = 1800 MPa and 614 HV0.05 are comparable to the literature results for this alloy. Fractographic observations with the scanning electron microscope were also performed in order to prove some plasticity observed during the strength tests.

  11. Impact of adding Saccharomyces strains on fermentation, aerobic stability, nutritive value, and select lactobacilli populations in corn silage.

    Science.gov (United States)

    Duniere, L; Jin, L; Smiley, B; Qi, M; Rutherford, W; Wang, Y; McAllister, T

    2015-05-01

    Bacterial inoculants can improve the conservation and nutritional quality of silages. Inclusion of the yeast Saccharomyces in the diet of dairy cattle has also been reported to be beneficial. The present study assessed the ability of silage to be used as a means of delivering Saccharomyces strains to ruminants. Two strains of Saccharomyces cerevisiae (strain 1 and 3)and 1 strain of Saccharomyces paradoxus (strain 2) were inoculated (10(3) cfu/g) individually onto corn forage that was ensiled in mini silos for 90 d. Fermentation characteristics, aerobic stability, and nutritive value of silages were determined and real-time quantitative PCR (RT-qPCR) was used to quantify S. cerevisiae, S.paradoxus, total Saccharomyces, fungal, and bacterial populations. Fermentation characteristics of silage inoculated with S1 were similar to control silage. Although strain 3 inoculation increased ash and decreased OM contents of silage (P = 0.017), no differences were observed in nutrient composition or fermentation profiles after 90 d of ensiling. Inoculation with Saccharomyces had no detrimental effect on the aerobic stability of silage. In vitro DM disappearance, gas production, and microbial protein synthesis were not affected by yeast inoculation.Saccharomyces strain 1 was quantified throughout ensiling, whereas strain 2 was detected only immediately after inoculation. Saccharomyces cerevisiae strain 3 was quantified until d 7 and detectable 90 d after ensiling. All inoculants were detected and quantified during aerobic exposure. Inoculation with Saccharomyces did not alter lactobacilli populations. Saccharomycetales were detected by RT-qPCR throughout ensiling in all silages. Both S. cerevisiae and S. paradoxus populations increased during aerobic exposure, demonstrating that the density of these yeast strains would increase between the time that silage was removed from storage and the time it was fed.

  12. A recyclable Au(I) catalyst for selective homocoupling of arylboronic acids: significant enhancement of nano-surface binding for stability and catalytic activity.

    Science.gov (United States)

    Zhang, Xin; Zhao, Haitao; Wang, Jianhui

    2010-08-01

    Au nanoparticles stabilized by polystyrene-co-polymethacrylic acid microspheres (PS-co-PMAA) were prepared and characterized via X-ray diffraction (XRD), and transmission electron microscope (TEM). The Au nanoparticles supported on the microspheres showed highly selective catalytic activity for homo-coupling reactions of arylboronic acids in a system of aryl-halides and arylboronic acids. X-ray photoelectron spectroscopy (XPS) spectra of the catalyst shows large amounts of Au(I) complexes band to the surface of the Au nanoparticles, which contributes to the selective homocoupling of the arylboronic acids. More importantly, this supported Au complex is a highly recyclable catalyst. The supported Au catalyst can be recycled and reused at least 6 times for a phenylboronic acid reactant, whereas the parent complex shows very low catalytic activity for this compound. The high catalytic activity of this material is attributed to: (1) the high surface to volume ratio which leads to more active sites being exposed to reactants; (2) the strong surface binding of the Au nanoparticle to the Au(I) complexes, which enhances both the stability and the catalytic activity of these complexes.

  13. Improving the stability and ethanol electro-oxidation activity of Pt catalysts by selectively anchoring Pt particles on carbon-nanotubes-supported-SnO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.J.; Wang, J.S.; Zhao, J.H.; Song, C.Y.; Wang, L.C. [School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou (China); Guo, X. [Department of Chemistry, Tsinghua University, Beijing (China)

    2012-10-15

    To improve the stability and activity of Pt catalysts for ethanol electro-oxidation, Pt nanoparticles were selectively deposited on carbon-nanotubes (CNTs)-supported-SnO{sub 2} to prepare Pt/SnO{sub 2}/CNTs and Pt/CNTs was prepared by impregnation method for reference study. X-ray diffraction (XRD) was used to confirm the crystalline structures of Pt/SnO{sub 2}/CNTs and Pt/CNTs. The stabilities of Pt/SnO{sub 2}/CNTs and Pt/CNTs were compared by analyzing the Pt size increase amplitude using transmission electron microscopy (TEM) images recorded before and after cyclic voltammetry (CV) sweeping. The results showed that the Pt size increase amplitude is evidently smaller for Pt/SnO{sub 2}/CNTs, indicating the higher stability of Pt/SnO{sub 2}/CNTs. Although both catalysts exhibit degradation of electrochemical active surface area (EAS) after CV sweeping, the EAS degradation for the former is lower, further confirming the higher stability of Pt/SnO{sub 2}/CNTs. CV and potentiostatic current-time curves were recorded for ethanol electro-oxidation on both catalysts before and after CV sweeping and the results showed that the mass specific activity of Pt/CNTs increases more than that of Pt/SnO{sub 2}/CNTs, indicating that Pt/CNTs experiences more severe evolution and is less stable. The calculated area specific activity of Pt/SnO{sub 2}/CNTs is larger than that of Pt/CNTs, indicating SnO{sub 2} can co-catalyze Pt due to plenty of interfaces between SnO{sub 2} and Pt. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. Plasmid Vectors for Xylella fastidiosa Utilizing a Toxin-Antitoxin System for Stability in the Absence of Antibiotic Selection.

    Science.gov (United States)

    Burbank, Lindsey P; Stenger, Drake C

    2016-08-01

    The phytopathogen Xylella fastidiosa causes disease in a variety of important crop and landscape plants. Functional genetic studies have led to a broader understanding of virulence mechanisms used by this pathogen in the grapevine host. Plasmid shuttle vectors are important tools in studies of bacterial genetics but there are only a limited number of plasmid vectors available that replicate in X. fastidiosa, and even fewer that are retained without antibiotic selection. Two plasmids are described here that show stable replication in X. fastidiosa and are effective for gene complementation both in vitro and in planta. Plasmid maintenance is facilitated by incorporation of the PemI/PemK plasmid addiction system, consisting of PemK, an endoribonuclease toxin, and its cognate antitoxin, PemI. Vector pXf20pemIK utilizes a native X. fastidiosa replication origin as well as a high-copy-number pUC origin for propagation in Escherichia coli cloning strains. Broad-host-range vector pBBR5pemIK is a medium- to low-copy-number plasmid based on the pBBR1 backbone. Both plasmids are maintained for extended periods of time in the absence of antibiotic selection, as well as up to 14 weeks in grapevine, without affecting bacterial fitness. These plasmids present an alternative to traditional complementation and expression vectors which rely on antibiotic selection for plasmid retention.

  15. Trait sexual motivation questionnaire: concept and validation.

    Science.gov (United States)

    Stark, Rudolf; Kagerer, Sabine; Walter, Bertram; Vaitl, Dieter; Klucken, Tim; Wehrum-Osinsky, Sina

    2015-04-01

    Trait sexual motivation defines a psychological construct that reflects the long-lasting degree of motivation for sexual activities, which is assumed to be the result of biological and sociocultural influences. With this definition, it shares commonalities with other sexuality-related constructs like sexual desire, sexual drive, sexual needs, and sexual compulsivity. The Trait Sexual Motivation Questionnaire (TSMQ) was developed in order to measure trait sexual motivation with its different facets. Several steps were conducted: First, items were composed assessing sexual desire, the effort made to gain sex, as well as specific sexual behaviors. Factor analysis of the data of a first sample (n = 256) was conducted. Second, the factor solution was verified by a confirmatory factor analysis in a second sample (n = 498) and construct validity was demonstrated. Third, the temporal stability of the TSMQ was tested in a third study (n = 59). Questionnaire data. The exploratory and confirmatory factor analyses revealed that trait sexual motivation is best characterized by four subscales: Solitary Sexuality, Importance of Sex, Seeking Sexual Encounters, and Comparison with Others. It could be shown that the test quality of the questionnaire is high. Most importantly for the trait concept, the retest reliability after 1 year was r = 0.87. Our results indicate that the TSMQ is indeed a suitable tool for measuring long-lasting sexual motivation with high test quality and high construct validity. A future differentiation between trait and state sexual motivation might be helpful for clinical as well as forensic research. © 2015 International Society for Sexual Medicine.

  16. Sexual revolutions

    NARCIS (Netherlands)

    Hekma, G.; Giami, A.

    2014-01-01

    The sexual revolution of 1960-1980 created a major break in attitudes and practices in Western societies. It created many new freedoms for gay men, youth and women, in terms of sexual imagery, information, and rights. Leftists denounced the revolution's consumerism whilst feminists lamented its

  17. Sexual Violence Prevention

    Science.gov (United States)

    ... Submit What's this? Submit Button Past Emails Sexual Violence Prevention Recommend on Facebook Tweet Share Compartir April ... stop sexual violence before it begins. Understanding Sexual Violence Sexual violence is any sexual activity where consent ...

  18. Senior Adult Sexuality in Age Segregated and Age Integrated Communities.

    Science.gov (United States)

    Weinstein, Stellye; Rosen, Efrem

    1988-01-01

    Middle-income older adults (N=314) responded to senior adult sexuality scale. Results showed that respondents who selected to reside in age-segregated leisure-type retirement communities exhibited significantly more sexual interest, sexual activities, and liberal sexual attitudes than did respondents residing in age-integrated mainstream…

  19. Sexual assault

    DEFF Research Database (Denmark)

    Larsen, M-L; Hilden, M; Lidegaard, Ø

    2015-01-01

    ) the relationship between victim and perpetrator. RESULTS: Two-thirds of the victims were aged 15-24 years. Seventy-five percent had met the perpetrator before the sexual assault and 70% reported the assault to the police. A physical injury was found in 53, and 27% sustained an anogenital lesion. Alcohol...... is important in creating an environment where women are not reluctant to seek help after a sexual assault. Young age and drinking alcohol were risk factors for sexual assault, and we need to address this when considering preventive strategies.......OBJECTIVE: To describe the victims of sexual assault and the circumstances in which the assaults occur. DESIGN: Descriptive case study. SETTING: Centre for Victims of Sexual Assault (CVSA), Rigshospitalet, Copenhagen, Denmark. POPULATION OR SAMPLE: A total of 2541 women attending CVSA from 2001...

  20. Sexual prejudice.

    Science.gov (United States)

    Herek, Gregory M; McLemore, Kevin A

    2013-01-01

    Despite shifts toward greater acceptance in U.S. public opinion and policy, lesbian, gay, and bisexual people remain widely stigmatized. This article reviews empirical research on sexual prejudice, that is, heterosexuals' internalization of cultural stigma, manifested in the form of negative attitudes toward sexual minorities and same-sex desires and behaviors. After briefly reviewing measurement issues, we discuss linkages between sexual prejudice and religion, gender, sexuality, and related variables, and consider how the cultural institutions encompassing these domains create a social context within which individual expressions of prejudice can meet important psychological needs. These include needs for securing social acceptance, affirming values that are central to one's self-concept, and avoiding anxiety and other negative emotions associated with threats to self-esteem. We conclude by discussing factors that may motivate heterosexuals to reduce their own sexual prejudice, including intergroup contact, as well as avenues for future empirical inquiry.

  1. Morpholinoethanesulfonic acid-based buffer system for improved detection limit and stability of the fluoride ion selective electrode

    International Nuclear Information System (INIS)

    Fouskaki, M.; Sotiropoulou, S.; Koci, M.; Chaniotakis, N.A.

    2002-01-01

    The zwitterionic morpholinoethanesulfonic acid (MES) is used as the basis for the development of a new total ionic strength adjustor buffer system for improving the analytical characteristics of fluoride sensor. Impedance analysis, atomic force microscopy (AFM) and dissolution studies of the LaF 3 crystal, together with the potential stability and sensor sensitivity over time have aided in the elucidation of the processes that take place at the surface of the LaF 3 crystal, that seem to determine the sensor behaviour. Even though AFM analysis shows that both buffers used (MES or acetate) cause a similar increase in surface roughness, the data from the other studies suggest that in the first case there is a reversible ion exchange process at the interface, while in the second case this process is irreversible, leading to fast poisoning of the crystal surface. The use of 0.5 M MES and NaCl buffer adjusted to pH 5.50 allows for the continuous operation of the sensor under flow injection analysis conditions for at least 5 days with sensitivity of 60 mV per decade [F - ], detection limit of 2.1x10 -7 M [F - ] and fast response time

  2. Selectivity and stability of herbicides and their tank mixtures for the seed yield of sunflower (Helianthus Annuus L.

    Directory of Open Access Journals (Sweden)

    G. Delchev

    2016-12-01

    Full Text Available Abstract. The research was conducted during 2012 – 2014 on pellic vertisol soil type. Under investigation were 4 sunflower hybrids (Helianthus annuus L.: hybrid Bacardy (an imitolerant hybrid by ClearField plus technology, hybrid Estiva (an imitolerant hybrid by ClearField technology, hybrid Sumico (a tribenuron-methyl tolerant hybrid by ExpessSun technology and hybrid Arizona (a hybrid by conventional technology. Factor A included the years of investigation. Factor B, herbicides and tank mixtures, included 20 rates. It includes 3 variants by ClearField plus technology, 5 variants by ClearField technology, 5 variants by ExpessSun technology and 7 variants by conventional technology. All variants are on herbicide Gardoprim plus gold 500 SC (Smetolachlor + terbuthylazine – 3.5 l/ha, which treated after sowing before emergence of the sunflower. It is found that the highest seed yield is obtained at herbicide tank mixture Pulsar plus + Stomp aqua by ClearField plus technology. Tank mixture Listego + Dash + Sharpen by ClearField technology and Express + Trend + Select super by ExpressSun technology also lead to obtaining high seed yields. The most unstable are secondary weed infested checks by the fourth technologies for sunflower growing which are treated with soil-applied herbicide Gardoprim plus gold only. Technologically the most valuable are herbicide combination Pulsar plus + Stomp aqua and herbicide Pulsar by ClearField plus technology, tank mixtures Listego + Dash + Sharpen and Listego + Dash by ClearField technology and Express + Trend + Select super and Express + Lactofol B + Select super by ExpressSun technology. Tank mixtures of herbicides Smerch, Pendigan, Wing, Raft, Pledge and Modown with Amalgerol premium by conventional technology have low estimates due to insufficient control of some weeds in sunflower crops.

  3. Older lesbian sexuality: identity, sexual behavior, and the impact of aging.

    Science.gov (United States)

    Averett, Paige; Yoon, Intae; Jenkins, Carol L

    2012-01-01

    In response to the very limited and mostly outdated literature on older lesbian sexuality, this exploratory study examined older lesbian sexual identity, romantic relationships, the impact of aging, and experiences of discrimination within these contexts. Utilizing an online survey that recruited via numerous online lesbian communities and snowball sampling, 456 lesbians over the age of 50 responded to closed, Likert scale, and open-ended questions that provided a preliminary understanding of older lesbian sexuality. The results indicated that older lesbians have experienced fluidity in past romantic and sexual relationships, as well as in erotic fantasies, despite strong identification with being lesbian. The findings also indicate a decreased focus on sexuality in the context of relationships, with more focus on stability and continuity. Future research is needed that provides greater specificity and detail about older lesbian conceptions of sexual behavior and sexual identity labels, as well as specific sexual behaviors.

  4. Composition, quality and oxidative stability of virgin olive oils from some selected wild olives (Olea europaea L. subsp. oleaster

    Directory of Open Access Journals (Sweden)

    Zarrouk, Mokhtar

    2008-12-01

    Full Text Available A study on the characterization of virgin olive oils from wild olives (Olea europaea L. subsp. oleaster was conducted in order to define new cultivars which are welladapted to the Tunisian environment and yield high quality oils. The study was done during the crop years 2003/04, 2004/05 and 2005/06. The main analytical parameters of the oils were evaluated: fatty acid compositions, chlorophylls, carotenoids, tocopherols and phenolic compounds as well as their relationship with oxidative stability. The fatty acid composition of all the wild olive trees tested produced virgin olive oil which complies with commercial standards, as well as for their appreciable amounts of tocopherols and phenolic compounds. Tocopherol analysis by HPLC revealed the presence of α, β, γ and δ tocopherols in all the studied olive oils. Total tocopherol content was significantly influenced by the varietal factor. It ranged from 310 (SB12 to 780 mg/kg (H3. As for total tocopherols, the amount of each tocopherol varied according to genotype. α tocopherol is the most prominent, whereas β, γ and δ tocopherols are less represented. Results showed a clear influence of total phenols and o-diphenols on virgin olive oil stability (R = 0.905, 0.963 P En este trabajo se han caracterizado los aceites obtenidos a partir de siete acebuches previamente seleccionados entre varias poblaciones de Olea europea L. Subsp. oleaster. El estudio se llevó a cabo durante las campañas de producción 2003/04, 2004/05 y 2005/06.Varios parámetros analíticos fueron evaluados: composiciones en ácidos grasos, pigmentos, tocoferoles, fenoles; así mismo, se investigó la relación de estos parámetros con la estabilidad de los aceites. Los resultados obtenidos mostraron que todas las muestras de frutos de acebuche produjeron aceites cuya composición de ácidos grasos, tocoferoles y compuestos fenólicos cumplió las normas comerciales para aceite de oliva virgen del Comit

  5. Selection gradients, the opportunity for selection, and the coefficient of determination.

    Science.gov (United States)

    Moorad, Jacob A; Wade, Michael J

    2013-03-01

    Abstract We derive the relationship between R(2) (the coefficient of determination), selection gradients, and the opportunity for selection for univariate and multivariate cases. Our main result is to show that the portion of the opportunity for selection that is caused by variation for any trait is equal to the product of its selection gradient and its selection differential. This relationship is a corollary of the first and second fundamental theorems of natural selection, and it permits one to investigate the portions of the total opportunity for selection that are involved in directional selection, stabilizing (and diversifying) selection, and correlational selection, which is important to morphological integration. It also allows one to determine the fraction of fitness variation not explained by variation in measured phenotypes and therefore attributable to random (or, at least, unknown) influences. We apply our methods to a human data set to show how sex-specific mating success as a component of fitness variance can be decoupled from that owing to prereproductive mortality. By quantifying linear sources of sexual selection and quadratic sources of sexual selection, we illustrate that the former is stronger in males, while the latter is stronger in females.

  6. Selected Fe and Mn (nano)oxides as perspective amendments for the stabilization of As in contaminated soils.

    Science.gov (United States)

    Michálková, Zuzana; Komárek, Michael; Veselská, Veronika; Číhalová, Sylva

    2016-06-01

    An amorphous Mn oxide (AMO), nanomaghemite, and nanomagnetite were used as potential amendments reducing the mobility of As in three contrasting contaminated soils differing in origin of As contamination. Adsorption experiments and XPS analyses combined with incubation batch experiments and pH-static leaching tests were used. The AMO showed excellent adsorption capacity for As(V) reaching a maximum of 1.79 mmol g(-1) at pH 7 and 8. Interestingly, the adsorption capacity in this case decreases with decreasing pH, probably as a result of AMO dissolution at lower pH values. Chemical sorption of As(V) onto AMO was further confirmed with XPS. Both Fe nano-oxides proved the highest adsorption capacity at pH 4 reaching 11 mg g(-1) of adsorbed As(V). The AMO was also the most efficient amendment for decreasing As concentrations in soil solutions during 8 weeks of incubation. Additionally, pH-static leaching tests were performed at pH 4, 5, 6, 7, and natural pH (not adjusted) and AMO again proved the highest ability to decrease As content in leachate. On the other hand, strong dissolution of this amendment at lower pH values (especially pH 4) was observed. For that reason, AMO appears as a promising stabilizing agent for As, especially in neutral, alkaline, or slightly acidic soils, where As(V) species are expected to be more mobile.

  7. Competencies for supporting a healthy sexual development of young people in care : interviews with a selection of professionals in Belgium, Denmark and The Netherlands

    NARCIS (Netherlands)

    Walpot, Mirjam; Riis Hansen, Gitte; Moentjes, Gwendy; Bernaards, Claire

    2017-01-01

    This report describes the results of the interviews that were held with professionals, policy makers, and researchers (working in the field of sexuality and/or residential and foster care) in three countries in order to answer the following question: ‘Which competencies (i.e. knowledge, skills, and

  8. The Relationship between Childhood Sexual Abuse and Sexual Dysfunction in Jamaican Adults

    Science.gov (United States)

    Swaby, Antoneal N.; Morgan, Kai A. D.

    2009-01-01

    This study examined the associations between early traumatic sexualization and later sexual dysfunction in a sample of 100 Jamaican adults while identifying the linkages between age, frequency of abuse, and gender on sexual functioning. Participants were selected via purposive and convenience sampling and divided equally into comparison and…

  9. Genomic Signatures of Sexual Conflict.

    Science.gov (United States)

    Kasimatis, Katja R; Nelson, Thomas C; Phillips, Patrick C

    2017-10-30

    Sexual conflict is a specific class of intergenomic conflict that describes the reciprocal sex-specific fitness costs generated by antagonistic reproductive interactions. The potential for sexual conflict is an inherent property of having a shared genome between the sexes and, therefore, is an extreme form of an environment-dependent fitness effect. In this way, many of the predictions from environment-dependent selection can be used to formulate expected patterns of genome evolution under sexual conflict. However, the pleiotropic and transmission constraints inherent to having alleles move across sex-specific backgrounds from generation to generation further modulate the anticipated signatures of selection. We outline methods for detecting candidate sexual conflict loci both across and within populations. Additionally, we consider the ability of genome scans to identify sexually antagonistic loci by modeling allele frequency changes within males and females due to a single generation of selection. In particular, we highlight the need to integrate genotype, phenotype, and functional information to truly distinguish sexual conflict from other forms of sexual differentiation. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Enhanced hydrothermal stability of Cu-ZSM-5 catalyst via surface modification in the selective catalytic reduction of NO with NH{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Tao; Shi, Juan; Liu, Jian, E-mail: liujian@cup.edu.cn; Wang, Daxi; Zhao, Zhen, E-mail: zhenzhao@cup.edu.cn; Cheng, Kai; Li, Jianmei

    2016-07-01

    Highlights: • The hydrothermal stability of Cu-ZSM-5 catalyst was enhanced after surface modification. • An inert silica layer was deposited on the surface of Cu-ZSM-5 and formed a protective layer. • The contact between Si and Cu and Al atoms could form Si-O-Al and Si- O−Cu bonds. • The redox and acidity properties of Cu-ZSM-5-CLD-Aged catalyst were largely retained. • The adsorption and activation of NO and NH{sub 3} was almost unchanged over Cu-ZSM-5-CLD catalyst before and after hydrothermal treatment. - Abstract: The surface of Cu-ZSM-5 catalyst was modified by chemical liquid deposition (CLD) of tetraethoxysilane (TEOS) for enhancing its hydrothermal stability in the selective catalytic reduction of NO with NH{sub 3}. After hydrothermal aging at 750 °C for 13 h, the catalytic performance of Cu-ZSM-5-Aged catalyst was significantly reduced for NO reduction in the entire temperature range, while that of Cu-ZSM-5-CLD-Aged catalyst was affected very little. The characterization results indicated that an inert silica layer was deposited on the surface of Cu-ZSM-5 and formed a protective layer, which prevents the detachment of Cu{sup 2+} from ZSM-5 ion-exchange positions and the dealumination of zeolite during the hydrothermal aging process. Based on the data it is hypothesized to be the primary reason for the high hydrothermal stability of Cu-ZSM-5-CLD catalyst.

  11. [Neurobiological foundations underlying normal and disturbed sexuality].

    Science.gov (United States)

    Krüger, T H C; Kneer, J

    2017-05-01

    Sexual functions are regulated by hormonal and neurochemical factors as well as neuronal networks. An understanding of these basic principles is necessary for the diagnostics, counselling and treatment of sexual problems. Description of essential mechanisms of sexual function on a neurochemical and neuronal level. Literature search, selection and discussion of relevant studies. Analogous to the dual control model there are primary inhibitory (e. g. serotonin) and excitatory neurotransmitter systems (e.g. sex steroids and dopamine). Moreover, neuronal structures have been identified that are responsible for processing sexual stimuli. These networks are altered in subjects with sexual disorders or by pharmacological treatment, e. g. antiandrogens and selective serotonin reuptake inhibitors (SSRI) CONCLUSION: Knowledge of the neurobiology of sexuality forms the foundations for the treatment of sexual dysfunctions in psychiatry and other disciplines.

  12. Violencia sexual

    OpenAIRE

    Carlos Tadayuki Oshikata

    2003-01-01

    Resumo: A violência sexual é um crime clandestino e subnotificado, praticado contra a liberdade sexual da mulher. Provoca traumas físicos e psíquicos, além de expor a doenças sexualmente transmissíveis e gravidez indesejada. Existem poucos serviços no Brasil que oferecem um atendimento especializado para diagnosticar e tratar as mulheres vítimas de violência sexual. A finalidade deste trabalho foi avaliar, através de um estudo descritivo e retrospectivo, 166 mulheres que compareceram na urgên...

  13. BIOPSYCHOSOCIAL DETERMINANTS OF HYPOACTIVE SEXUAL DESIRE IN WOMEN: A NARRATIVE REVIEW

    OpenAIRE

    Malary, Mina; Khani, Soghra; Pourasghar, Mehdi; Moosazadeh, Mahmood; Hamzehgardeshi, Zeinab

    2015-01-01

    Background: As a mental response to sexual stimuli, sexual desire determines human sexual behavior and represents the cognitive capacity of sexual stimulation, so that avoiding sexual activity has a very negative effect on the discharge of intimacy and joy in couple?s relationship and threatens the stability relationship, which can finally end in sexual dissatisfaction and divorce; it may even affect the reproduction. This study, reviews the literature on biopsychosocial determinants of hypoa...

  14. Bisindeno-annulated pentacenes with exceptionally high photo-stability and ordered molecular packing: Simple synthesis by a regio-selective Scholl reaction

    KAUST Repository

    Naibi Lakshminarayana, Arun; Chang, Jingjing; Luo, Jie; Zheng, Bin; Huang, Kuo-Wei; Chi, Chunyan

    2015-01-01

    Bisindeno-annulated pentacenes 3a and 3b were synthesized by a simple regio-selective, FeCl3-mediated Scholl reaction from the corresponding 6,13-diaryl pentacene precursors. The fusion of two indeno-units dramatically changes the electronic properties and chemical reactivity of pentacene and the obtained compounds exhibited exceptionally high photo-stability in the solution, with a half-life time of 11.2 (3a) and 32.0 (3b) days under ambient light and air conditions. Ordered molecular packing with a small π-π stacking distance was observed in the single crystals of 3a and 3b. Our research provides a promising strategy to access stable higher order acenes with controlled molecular order. This journal is

  15. Gender Differences In Premarital Sexual Permissiveness Among ...

    African Journals Online (AJOL)

    This paper examined the concept of premariatal sexual permissiveness among selected University undergraduates in a state owned university in Nigeria, believing that the policy of non-residential status of the University will facilitate premarital sexual activity among the students. Using a total of 400 purposively selected ...

  16. A Copper(II)-Paddlewheel Metal-Organic Framework with Exceptional Hydrolytic Stability and Selective Adsorption and Detection Ability of Aniline in Water.

    Science.gov (United States)

    Chen, Ya; Wang, Bin; Wang, Xiaoqing; Xie, Lin-Hua; Li, Jinping; Xie, Yabo; Li, Jian-Rong

    2017-08-16

    Copper(II)-paddlewheel-based metal-organic frameworks (CP-MOFs) represent a unique subclass of MOFs with highly predictable porous structures, facile syntheses, and functional open metal sites. However, the lack of high hydrolytic stability is an obstacle for CP-MOFs in many practical applications. In this work, we report a new CP-MOF, [Cu 4 (tdhb)] (BUT-155), which is constructed from a judiciously designed carboxylate ligand with high coordination connectivity (octatopic), abundant hydrophobic substituents (six methyl groups), and substituent constrained geometry (tetrahedral backbone), tdhb 8- [H 8 tdhb = 3,3',5,5'-tetrakis(3,5-dicarboxyphenyl)-2,2',4,4',6,6'-hexamethylbiphenyl)]. BUT-155 shows high porosity with a Brunauer-Emmett-Teller surface area of 2070 m 2 /g. Quite interestingly, this CP-MOF retains its structural integrity after being treated in water for 10 days at room temperature or in boiling water for 24 h. To the best of our knowledge, BUT-155 represents the first CP-MOF that is demonstrated to retain its structural integrity in boiling water. The high hydrolytic stability of BUT-155 allowed us to carry out adsorption studies of water vapor and aqueous organic pollutants on it. Water-vapor adsorption reveals a sigmoidal isotherm and a high uptake (46.7 wt %), which is highly reversible and regenerable. In addition, because of the availability of soft-acid-type open Cu(II) sites, BUT-155 shows a high performance for selective adsorption of soft-base-type aniline over water or phenol, and a naked-eye detectable color change for the MOF sample accompanies this. The adsorption selectivity and high adsorption capacity of aniline in BUT-155 are also well-interpreted by single-crystal structures of the water- and aniline-included phases of BUT-155.

  17. Tween 20-stabilized gold nanoparticles combined with adenosine triphosphate-BODIPY conjugates for the fluorescence detection of adenosine with more than 1000-fold selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Szu-Ying; Shih, Ya-Chen [Department of Chemistry, National Sun Yat-sen University, Taiwan (China); Tseng, Wei-Lung, E-mail: tsengwl@mail.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Taiwan (China); School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Taiwan (China); Center for Nanoscience and Nanotechnology, National Sun Yat-sen University, Taiwan (China); Center for Stem Cell Research, Kaohsiung Medical University, Taiwan (China)

    2015-02-01

    Graphical abstract: A simple, enzyme-free, label-free, sensitive and selective system was developed for detecting adenosine based on the use of Tween 20-stabilized gold nanoparticles as an efficient quencher for boron dipyrromethene-conjugated adenosine 5′-triphosphate and as a recognition element for adenosine. - Highlights: • The proposed method can detect adenosine with more than 1000-fold selectivity. • The analysis of adenosine is rapid (∼6 min) using the proposed method. • This method provided better sensitivity for adenosine as compared to aptamer-based sensors. • This method can be applied for the determination of adenosine in urine. - Abstract: This study describes the development of a simple, enzyme-free, label-free, sensitive, and selective system for detecting adenosine based on the use of Tween 20-stabilized gold nanoparticles (Tween 20-AuNPs) as an efficient fluorescence quencher for boron dipyrromethene-conjugated adenosine 5′-triphosphate (BODIPY-ATP) and as a recognition element for adenosine. BODIPY-ATP can interact with Tween 20-AuNPs through the coordination between the adenine group of BODIPY-ATP and Au atoms on the NP surface, thereby causing the fluorescence quenching of BODIPY-ATP through the nanometal surface energy transfer (NSET) effect. When adenosine attaches to the NP surface, the attached adenosine exhibits additional electrostatic attraction to BODIPY-ATP. As a result, the presence of adenosine enhances the efficiency of AuNPs in fluorescence quenching of BODIPY-ATP. The AuNP-induced fluorescence quenching of BODIPY-ATP progressively increased with an increase in the concentration of adenosine; the detection limit at a signal-to-noise ratio of 3 for adenosine was determined to be 60 nM. The selectivity of the proposed system was more than 1000-fold for adenosine over any adenosine analogs and other nucleotides. The proposed system combined with a phenylboronic acid-containing column was successfully applied to the

  18. Tween 20-stabilized gold nanoparticles combined with adenosine triphosphate-BODIPY conjugates for the fluorescence detection of adenosine with more than 1000-fold selectivity

    International Nuclear Information System (INIS)

    Hung, Szu-Ying; Shih, Ya-Chen; Tseng, Wei-Lung

    2015-01-01

    Graphical abstract: A simple, enzyme-free, label-free, sensitive and selective system was developed for detecting adenosine based on the use of Tween 20-stabilized gold nanoparticles as an efficient quencher for boron dipyrromethene-conjugated adenosine 5′-triphosphate and as a recognition element for adenosine. - Highlights: • The proposed method can detect adenosine with more than 1000-fold selectivity. • The analysis of adenosine is rapid (∼6 min) using the proposed method. • This method provided better sensitivity for adenosine as compared to aptamer-based sensors. • This method can be applied for the determination of adenosine in urine. - Abstract: This study describes the development of a simple, enzyme-free, label-free, sensitive, and selective system for detecting adenosine based on the use of Tween 20-stabilized gold nanoparticles (Tween 20-AuNPs) as an efficient fluorescence quencher for boron dipyrromethene-conjugated adenosine 5′-triphosphate (BODIPY-ATP) and as a recognition element for adenosine. BODIPY-ATP can interact with Tween 20-AuNPs through the coordination between the adenine group of BODIPY-ATP and Au atoms on the NP surface, thereby causing the fluorescence quenching of BODIPY-ATP through the nanometal surface energy transfer (NSET) effect. When adenosine attaches to the NP surface, the attached adenosine exhibits additional electrostatic attraction to BODIPY-ATP. As a result, the presence of adenosine enhances the efficiency of AuNPs in fluorescence quenching of BODIPY-ATP. The AuNP-induced fluorescence quenching of BODIPY-ATP progressively increased with an increase in the concentration of adenosine; the detection limit at a signal-to-noise ratio of 3 for adenosine was determined to be 60 nM. The selectivity of the proposed system was more than 1000-fold for adenosine over any adenosine analogs and other nucleotides. The proposed system combined with a phenylboronic acid-containing column was successfully applied to the

  19. Stability-Diversity Tradeoffs Impose Fundamental Constraints on Selection of Synthetic Human VH/VL Single-Domain Antibodies from In Vitro Display Libraries.

    Science.gov (United States)

    Henry, Kevin A; Kim, Dae Young; Kandalaft, Hiba; Lowden, Michael J; Yang, Qingling; Schrag, Joseph D; Hussack, Greg; MacKenzie, C Roger; Tanha, Jamshid

    2017-01-01

    Human autonomous V H /V L single-domain antibodies (sdAbs) are attractive therapeutic molecules, but often suffer from suboptimal stability, solubility and affinity for cognate antigens. Most commonly, human sdAbs have been isolated from in vitro display libraries constructed via synthetic randomization of rearranged V H /V L domains. Here, we describe the design and characterization of three novel human V H /V L sdAb libraries through a process of: (i) exhaustive biophysical characterization of 20 potential V H /V L sdAb library scaffolds, including assessment of expression yield, aggregation resistance, thermostability and tolerance to complementarity-determining region (CDR) substitutions; (ii) in vitro randomization of the CDRs of three V H /V L sdAb scaffolds, with tailored amino acid representation designed to promote solubility and expressibility; and (iii) systematic benchmarking of the three V H /V L libraries by panning against five model antigens. We isolated ≥1 antigen-specific human sdAb against four of five targets (13 V H s and 7 V L s in total); these were predominantly monomeric, had antigen-binding affinities ranging from 5 nM to 12 µM (average: 2-3 µM), but had highly variable expression yields (range: 0.1-19 mg/L). Despite our efforts to identify the most stable V H /V L scaffolds, selection of antigen-specific binders from these libraries was unpredictable (overall success rate for all library-target screens: ~53%) with a high attrition rate of sdAbs exhibiting false positive binding by ELISA. By analyzing V H /V L sdAb library sequence composition following selection for monomeric antibody expression (binding to protein A/L followed by amplification in bacterial cells), we found that some V H /V L sdAbs had marked growth advantages over others, and that the amino acid composition of the CDRs of this set of sdAbs was dramatically restricted (bias toward Asp and His and away from aromatic and hydrophobic residues). Thus, CDR sequence

  20. Sexual abuse

    Directory of Open Access Journals (Sweden)

    Iztok Takač

    2012-11-01

    Conclusions: Effective and efficient treatment of victims of sexual abuse requires a systematic approach to the patient, starting with a thorough history, and continuing with a clinical investigation, diagnosis, treatment and prevention of the consequences of sexual abuse. The complete management must include sampling of any potential biological traces from the body of the victim. The key to success is a coordinated cooperation with investigators and forensics.

  1. Enigmatic Sexuality

    DEFF Research Database (Denmark)

    Zeuthen, Katrine Egede; Gammelgård, Judy

    2017-01-01

    ? Divided into three sections, Clinical Encounters in Sexuality begins with six chapters on important themes in queer theory: identity, desire, perversion, pleasure, discourse and ethics. Section two includes fourteen responses to the chapters in section one by practising psychoanalysts and psychoanalytic......: psychoanalytic and queer. The book is edited by two psychoanalytic practitioners — one Kleinian, one Freudian-Lacanian — who also have research expertise in sexuality studies. All pieces are new and have been commissioned....

  2. Sexual Jealousy

    Directory of Open Access Journals (Sweden)

    David M. Buss

    2013-09-01

    Full Text Available Sexual jealousy is a basic emotion. Although it lacks a distinctive facial expression and is unlikely to solve problems of survival, it evolved because it solves adaptive problems of mating. Some adaptive functions are similar in men and women at one level of abstraction, such as warding off potential mate poachers and deterring relationship defection. Other functions are sex-differentiated, such as increasing paternity probability for men and monopolizing a mate's economic commitments for women. Dozens of studies have documented sex-differentiated design features of jealousy: The relative upset about sexual and emotional aspects of infidelity; processing speed and memorial recall of sexual and emotional infidelity cues; physiological distress to sexual and emotional infidelity cues; qualities of same-sex rivals that evoke jealousy, such as superior job prospects versus greater physical attractiveness; triggers of mate retention tactics; jealous interrogations following the discovery of infidelity; and whether an infidelity produces forgiveness or breakup. Although showing all the hallmarks of evolved functionality, sexual jealousy also leads to tremendous destruction, from humiliation to homicide. By these scientific theoretical and empirical criteria, sexual jealousy is properly considered not only "basic" but also "one of the most important emotions".

  3. [Sexuality in adolescents].

    Science.gov (United States)

    Molina, R; Araa, S; Ibazeta, G; Jordan, P; Lagos, E

    1987-01-01

    A survey of knowledge, attitude, and practices regarding human reproduction and sexuality was undertaken in 2 groups of secondary school students in Chile to assess whether greater knowledge of reproduction and sexuality is associated with greater permissiveness and earlier initiation of sexual activity. Students in 2 public schools, 1 coeducational and 1 for female students only, were of lower middle class background, while students at the coeducational private school were of higher socioeconomic status. An anonymous, semiclosed questionnaire was administered to students in the 3 schools. The schools were selected because their directors agreed to permit the study. 14.8% of the 351 public school students were aged 14 or under and 77.8% were 15-18, while 99.5% of the 197 private school students were aged 15-18. The students' levels of knowledge of human reproduction and sexuality were measured through direct personal assessments by the students themselves and through 21 questions to confirm the assessments. At least 93% of students in all schools said their level of knowledge was medium or high, but the test indicated that only 64% of public school students and 75% of private school students actually had medium or high levels of knowledge. 45.9% of private and 27.9% of public school students felt the information they received from their schools about sexuality was adequate, while 41.9% of private and 60.9% of public school students felt it was insufficient. There were no significant differences in the opinions of the 2 groups of students concerning premarital sex, but the reasons given by the private school students to explain their attitudes expressed a greater sense of commitment to the partner, while those of the public school students tended to be more functional. Among public school students, 38.7% of males and 9.7% of females reported having had sexual relations, while among private school students, 17.7% of males and 4.4% of females reported having done so

  4. Prioritization of Potential Mates' History of Sexual Fidelity During a Conjoint Ranking Task.

    Science.gov (United States)

    Mogilski, Justin K; Wade, T Joel; Welling, Lisa L M

    2014-07-01

    This series of studies is the first to use conjoint analysis to examine how individuals make trade-offs during mate selection when provided information about a partner's history of sexual infidelity. Across three studies, participants ranked profiles of potential mates, with each profile varying across five attributes: financial stability, physical attractiveness, sexual fidelity, emotional investment, and similarity. They also rated each attribute separately for importance in an ideal mate. Overall, we found that for a long-term mate, participants prioritized a potential partner's history of sexual fidelity over other attributes when profiles were ranked conjointly. For a short-term mate, sexual fidelity, physical attractiveness, and financial stability were equally important, and each was more important than emotional investment and similarity. These patterns contrast with participants' self-reported importance ratings of each individual attribute. Our results are interpreted within the context of previous literature examining how making trade-offs affect mate selection. © 2014 by the Society for Personality and Social Psychology, Inc.

  5. “The pleasure is better as I’ve gotten older”: Sexual Health, Sexuality, and Sexual Risk Behaviors among Older Women Living with HIV

    Science.gov (United States)

    Taylor, Tonya N.; Munoz-Plaza, Corrine E.; Goparaju, Lakshmi; Martinez, Omar; Holman, Susan; Minkoff, Howard L.; Karpiak, Stephen E.; Gandhi, Monica; Cohen, Mardge H.; Golub, Elizabeth T.; Levine, Alexandra M.; Adedimeji, Adebola A.; Gonsalves, Rebecca; Bryan, Tiffany; Connors, Nina; Schechter, Gabrielle; Wilson, Tracey E.

    2016-01-01

    There is limited research examining the sexual health and wellbeing of older women living with HIV (OWLH). Most studies focus on sexual dysfunction, leaving aside the richer context of sexuality and sexual health, including the effect of age-related psychosocial and interpersonal changes on sexual health behaviors. Guided by the integrative biopsychosocial model and the sexual health model, this study explored the importance of sex and sexuality among OWLH to identify their sexual health and HIV prevention needs for program planning. A purposive sample (n=50) of OWLH was selected from a parent study (n=2,052). We conducted 8 focus groups and 41 in-depth interviews with 50 African American and Latina OWLH aged 50–69 years old in three U.S. cities. The triangulation approach was used to synthesize the data. Six salient themes emerged: sexual pleasure changes due to age, sexual freedom as women age, the role of relationships in sexual pleasure, changes in sexual ability and sexual health needs, sexual risk behaviors, and ageist assumptions about older women’s sexuality. We found that sexual pleasure and the need for intimacy continue to be important for OWLH, but that changing sexual abilities and sexual health needs, such as the reduction of sexual desire, as well as increased painful intercourse due to menopause-associated vaginal drying, were persistent barriers to sexual fulfillment and satisfaction. Particular interpersonal dynamics, including low perceptions of the risk of HIV transmission as related to gender, viral suppression and habitual condomless sex with long term partners without HIV transmission have resulted in abandoning safer sex practices with serodiscordant partners. These findings suggest that HIV prevention for OWLH should focus on how sexual function and satisfaction intersect with sexual risk. HIV prevention for OWLH should promote ways to maintain satisfying and safe sex lives among aging women. PMID:27220311

  6. "The Pleasure Is Better as I've Gotten Older": Sexual Health, Sexuality, and Sexual Risk Behaviors Among Older Women Living With HIV.

    Science.gov (United States)

    Taylor, Tonya N; Munoz-Plaza, Corrine E; Goparaju, Lakshmi; Martinez, Omar; Holman, Susan; Minkoff, Howard L; Karpiak, Stephen E; Gandhi, Monica; Cohen, Mardge H; Golub, Elizabeth T; Levine, Alexandra M; Adedimeji, Adebola A; Gonsalves, Rebecca; Bryan, Tiffany; Connors, Nina; Schechter, Gabrielle; Wilson, Tracey E

    2017-05-01

    There is limited research examining the sexual health and well-being of older women living with HIV (OWLH). Most studies focus on sexual dysfunction, leaving aside the richer context of sexuality and sexual health, including the effect of age-related psychosocial and interpersonal changes on sexual health behaviors. Guided by the integrative biopsychosocial model and the sexual health model, this study explored the importance of sex and sexuality among OWLH to identify their sexual health and HIV prevention needs for program planning. A purposive sample (n = 50) of OWLH was selected from a parent study (n = 2052). We conducted 8 focus groups and 41 in-depth interviews with 50 African American and Latina OWLH aged 50-69 years old in three U.S. cities. The triangulation approach was used to synthesize the data. Six salient themes emerged: sexual pleasure changes due to age, sexual freedom as women age, the role of relationships in sexual pleasure, changes in sexual ability and sexual health needs, sexual risk behaviors, and ageist assumptions about older women's sexuality. We found that sexual pleasure and the need for intimacy continue to be important for OWLH, but that changing sexual abilities and sexual health needs, such as the reduction of sexual desire, as well as increased painful intercourse due to menopause-associated vaginal drying, were persistent barriers to sexual fulfillment and satisfaction. Particular interpersonal dynamics, including low perceptions of the risk of HIV transmission as related to gender, viral suppression, and habitual condomless sex with long-term partners without HIV transmission have resulted in abandoning safer sex practices with serodiscordant partners. These findings suggest that HIV prevention for OWLH should focus on how sexual function and satisfaction intersect with sexual risk. HIV prevention for OWLH should promote ways to maintain satisfying and safe sex lives among aging women.

  7. Systematic modulation and enhancement of CO{sub 2} : N{sub 2} selectivity and water stability in an isoreticular series of bio-MOF-11 analogues

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tao; Chen, De-Li; Sullivan, Jeanne E.; Kozlowski, Mark T.; Johnson, J Karl; Rosi, Nathaniel L.

    2013-02-01

    An isoreticular series of cobalt-adeninate bio-MOFs (bio-MOFs 11-14) is reported. The pores of bio-MOFs 11-14 are decorated with acetate, propionate, butyrate, and valerate, respectively. The nitrogen (N{sub 2}) and carbon dioxide (CO{sub 2}) adsorption properties of these materials are studied and compared. The isosteric heats of adsorption for CO{sub 2} are calculated, and the CO{sub 2}:N{sub 2} selectivities for each material are 10 determined. As the lengths of the aliphatic chains decorating the pores in bio-MOFs 11-14 increase, the BET surface areas decrease from 1148 m{sup 2}/g to 17 m{sup 2}/g while the CO{sub 2}:N{sub 2} selectivities predicted from ideal adsorbed solution theory at 1 bar and 273 K for a 10:90 CO{sub 2}:N{sub 2} mixture range from 73:1 for bio-MOF-11 to 123:1 for bio-MOF-12 and finally to 107:1 for bio-MOF-13. At 298 K, the selectivities are 43:1 for bio-MOF-11, 52:1 for bio-MOF-12, and 40:1 for bio-MOF-13. Additionally, it is shown that 15 bio-MOF-14 exhibits a unique molecular sieving property that allows it to adsorb CO{sub 2} but not N{sub 2} at 273 and 298 K. Finally, the water stability of bio-MOFs 11-14 increases with increasing aliphatic chain length. Bio-MOF-14 exhibits no loss of crystallinity or porosity after soaking in water for one month.

  8. A simple and selective colorimetric mercury (II) sensing system based on chitosan stabilized gold nanoparticles and 2,6-pyridinedicarboxylic acid

    International Nuclear Information System (INIS)

    Tian, Kun; Siegel, Gene; Tiwari, Ashutosh

    2017-01-01

    The development of simple and cost-effective methods for the detection and treatment of Hg 2+ in the environment is an important area of research due to the serious health risk that Hg 2+ poses to humans. Colorimetric sensing based on the induced aggregation of nanoparticles is of great interest since it offers a low cost, simple, and relatively rapid procedure, making it perfect for on-site analysis. Herein we report the development of a simple colorimetric sensor for the selective detection and estimation of mercury ions in water, based on chitosan stabilized gold nanoparticles (AuNPs) and 2,6-pyridinedicarboxylic acid (PDA). In the presence of Hg 2+ , PDA induces the aggregation of AuNPs, causing the solution to change colors varying from red to blue, depending on the concentration of Hg 2+ . The formation of aggregated AuNPs in the presence of Hg 2+ was confirmed using transmission electron microscopy (TEM) and UV–Vis spectroscopy. The method exhibits linearity in the range of 300 nM to 5 μM and shows excellent selectivity towards Hg 2+ among seventeen different metal ions and was successfully applied for the detection of Hg 2+ in spiked river water samples. The developed technique is simple and superior to the existing techniques in that it allows detection of Hg 2+ using the naked eye and simple and rapid colorimetric analysis, which eliminates the need for sophisticated instruments and sample preparation methods. - Highlights: • A simple colorimetric method for detection of Hg 2+ in water was proposed. • Au nanoparticles and 2,6-pyridinedicarboxylic acid were used for sensing Hg 2+ . • Sensing mechanisms were demonstrated by TEM and UV–Visible measurements. • It showed the solution color changes from red to blue upon addition of Hg 2+ . • The method selectively detected Hg 2+ among seventeen different metal ions.

  9. Selective contribution of each hamstring muscle to anterior cruciate ligament protection and tibiofemoral joint stability in leg-extension exercise: a simulation study.

    Science.gov (United States)

    Biscarini, Andrea; Botti, Fabio Massimo; Pettorossi, Vito Enrico

    2013-09-01

    A biomechanical model was developed to simulate the selective effect of the co-contraction force provided by each hamstring muscle on the shear and compressive tibiofemoral joint reaction forces, during open kinetic-chain knee-extension exercises. This model accounts for instantaneous values of knee flexion angle [Formula: see text], angular velocity and acceleration, and for changes in magnitude, orientation, and application point of external resistance. The tibiofemoral shear force (TFSF) largely determines the tensile force on anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). Biceps femoris is the most effective hamstring muscle in decreasing the ACL-loading TFSF developed by quadriceps contractions for [Formula: see text]. In this range, the semimembranosus generates the dominant tibiofemoral compressive force, which enhances joint stability, opposes anterior/posterior tibial translations, and protects cruciate ligaments. The semitendinosus force provides the greatest decreasing gradient of ACL-loading TFSF for [Formula: see text], and the greatest increasing gradient of tibiofemoral compressive force for [Formula: see text]. However, semitendinosus efficacy is strongly limited by its small physiological section. Hamstring muscles behave as a unique muscle in enhancing the PCL-loading TFSF produced by quadriceps contractions for [Formula: see text]. The levels of hamstrings co-activation that suppress the ACL-loading TFSF considerably shift when the knee angular acceleration is changed while maintaining the same level of knee extensor torque by a concurrent adjustment in the magnitude of external resistance. The knowledge of the specific role and the optimal activation level of each hamstring muscle in ACL protection and tibiofemoral stability are fundamental for planning safe and effective rehabilitative knee-extension exercises.

  10. Microwave-Assisted Synthesis of Arene Ru(II Complexes Induce Tumor Cell Apoptosis Through Selectively Binding and Stabilizing bcl-2 G-Quadruplex DNA

    Directory of Open Access Journals (Sweden)

    Yanhua Chen

    2016-05-01

    Full Text Available A series of arene Ru(II complexes coordinated with phenanthroimidazole derivatives, [(η6-C6H6Ru(lCl]Cl(1b L = p-ClPIP = 2-(4-Chlorophenylimidazole[4,5f] 1,10-phenanthroline; 2b L = m-ClPIP = 2-(3-Chlorophenylimidazole[4,5f] 1,10-phenanthroline; 3b L = p-NPIP = 2-(4-Nitrophenylimidazole[4,5f] 1,10-phenanthroline; 4b L = m-NPIP = 2-(3-Nitrophenyl imidazole [4,5f] 1,10-phenanthroline were synthesized in yields of 89.9%–92.7% under conditions of microwave irradiation heating for 30 min to liberate four arene Ru(II complexes (1b, 2b, 3b, 4b. The anti-tumor activity of 1b against various tumor cells was evaluated by MTT assay. The results indicated that this complex blocked the growth of human lung adenocarcinoma A549 cells with an IC50 of 16.59 μM. Flow cytometric analysis showed that apoptosis of A549 cells was observed following treatment with 1b. Furthermore, the in vitro DNA-binding behaviors that were confirmed by spectroscopy indicated that 1b could selectively bind and stabilize bcl-2 G-quadruplex DNA to induce apoptosis of A549 cells. Therefore, the synthesized 1b has impressive bcl-2 G-quadruplex DNA-binding and stabilizing activities with potential applications in cancer chemotherapy.

  11. [Contextualization of sexual initiation and individual barriers to the use of contraceptives by adolescents of Lima, Huamanga, and Iquitos].

    Science.gov (United States)

    Carmona, Gloria; Beltran, Jessica; Calderón, María; Piazza, Marina; Chávez, Susana

    2017-01-01

    To contextualize sexual initiation and barriers to the use of contraceptives by adolescents as well as the acquisition of adequate knowledge regarding contraception and sexually transmitted diseases. This quantitative and qualitative study evaluated adolescents living in three cities with high pregnancy rates in Peru: Iquitos, Huamanga, and Lima. Subjects were invited to participate in the study via Facebook. Questionnaires were then used to select adolescents who met the inclusion criteria, and interviews were conducted to obtain detailed data regarding the study topic. A total of 33 women and 23 men aged 18 to 19 years participated in the study. The age of onset of sexual activity ranged from 14 to 16 years; the main reasons for sexual initiation were sexual desire among men and pressure from the partner among women; in most cases, the sexual partner was an occasional companion for men and a boyfriend for women. The barriers related to the use of contraceptives were the financial stability of the partner, responsibility of the female partner when using contraceptives, limited capacity to negotiate choices, fear of abandonment by the male partner for demanding the use of contraceptives, and the reduction of sexual sensitivity with the use of condoms. The barriers identified in this study limit the use of contraceptives and indicate the need to develop specific strategies to strengthen the interpersonal skills of adolescents and provide accurate information about the risks of unprotected sex.

  12. Identidad sexual y performatividad

    Directory of Open Access Journals (Sweden)

    Córdoba García, David

    2003-11-01

    Full Text Available This text intends to approach the question of sexual identity as it has been defined in queer theory, and particularly in Judith Butler's work. The notion of performativity, closely related to a conception of the social as an open field of power relations where all identity is a contingent and precarious stabilization, leads to a politicization of identity that implies a second step further from its denaturalization. Identity is the place from which we can articulate a resistance politics, and its open and incomplete character is what allows its resignification.

  13. Sexuality and Sexual Rights in Muslim Societies

    OpenAIRE

    Liz Ercevik Amado

    2009-01-01

    In August 2008, the Coalition for Sexual and Bodily Rights in Muslim Societies (CSBR) organized the CSBR Sexuality Institute, the first international Institute on sexuality and sexual rights in Muslim societies in Malaysia. Liz Amado presents how the Institute expanded the discourse, knowledge and thinking around sexuality in Muslim societies, as well as providing a unique space for the much needed exchange of information and experience among sexual rights advocates. Development (2009) 52, 59...

  14. Rationally Irrational: The Case of Sexual Burglary.

    Science.gov (United States)

    Pedneault, Amelie; Beauregard, Eric; Harris, Danielle A; Knight, Raymond A

    2015-08-01

    The present study investigated rationality in sexually motivated burglaries. Specifically, we analyzed the situational cues identified by sexual burglars in their target selection. The research project investigated 224 individual incidents of residential burglary with apparent sexual motivations. Situational characteristics of the incidents were recorded and analyzed using forward sequential regressions. Results indicated that most sexually motivated burglaries occurred in occupied residences with deficient physical guardianship, when the victim was alone. Violence, theft, penetration, and fetishism were found to be committed in circumstances that increased the benefits and lowered the risks. Results showed that sexual burglary is rational in nature-sexual burglars chose residences that were easy to break into. We found little support for the premise that such opportunities arose while carrying out regular burglaries. Instead, the data indicated that sexual burglars acted opportunistically on situational cues that are markedly dissimilar to those of regular burglars. © The Author(s) 2014.

  15. Sexual safety and sexual security among young Black women who have sex with women and men.

    Science.gov (United States)

    Alexander, Kamila Anise; Fannin, Ehriel F

    2014-01-01

    To examine sexuality narratives of Black women who have sex with women and men and explore factors that influence their sexual safety and sexual security. Secondary qualitative content analysis. We recruited young self-identified Black women from beauty salons and community-based organizations. Our sample included a subset of five sexually active, Black women age 19 to 25 who reported engaging in sexual relationships with women and men. Participants were selected from a larger parent study that included sexuality narratives from 25 women. We analyzed interview transcripts in which participants described sexual relationships. We used constant comparative techniques and conventional content analysis methodology. We uncovered three themes illustrating influences on sexual safety and sexual security: institutional expectations, emotional connectedness, and sexual behaviors. From this analysis, we derive valuable insights into decision-making processes within sexual relationships from the perspectives of young Black women who have sex with women and men. Clinicians and investigators can use these findings to inform programs designed to improve the sexual health of this often invisible group of women. Nurses are uniquely positioned to support young women as they navigate societal institutions and emotional experiences that inform future sexual decisions and behaviors. © 2014 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses.

  16. The nano-fractal structured tungsten oxides films with high thermal stability prepared by the deposition of size-selected W clusters

    Energy Technology Data Exchange (ETDEWEB)

    Park, Eun Ji; Kim, Young Dok [Sungkyunkwan University, Department of Chemistry, Suwon (Korea, Republic of); Dollinger, Andreas; Huether, Lukas; Blankenhorn, Moritz; Koehler, Kerstine; Gantefoer, Gerd [Konstanz University, Department of Physics, Constance (Germany); Seo, Hyun Ook [Sangmyung University, Department of Chemistry and Energy Engineering, Seoul (Korea, Republic of)

    2017-06-15

    Size-selected W{sub n}{sup -} clusters (n = 1650) were deposited on the highly ordered pyrolytic graphite surface at room temperature under high vacuum conditions by utilizing a magnetron sputtering source and a magnet sector field. Moreover, geometrical structure and surface chemical states of deposited clusters were analyzed by in situ scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy, respectively. The formation of 2-D islands (lateral size ∝150 nm) with multiple dendritic arms was observed by STM, and the structure of the individual W{sub 1650} clusters survived within the dendritic arms. To study the thermal stability of the nano-fractal structure under the atmospheric conditions, the sample was brought to the ambient air conditions and sequentially post-annealed at 200, 300, and 500 C in the air. The nano-fractal structure was maintained after the 1st post-annealing process at 200 C for 1 h in the air, and the subsequent 2nd post-annealing at 300 C (for 1 h, in the air) also did not induce any noticeable change in the topological structure of the sample. The topological changes were observed only after the further post-annealing at a higher temperature (at 500 C, 1 h) in the air. We show high potential use of these nano-structured films of tungsten oxides in ambient conditions. (orig.)

  17. Selective hydrogen detection at high temperature by using yttria-stabilized zirconia-based sensor with coupled metal-oxide-based sensing electrodes

    International Nuclear Information System (INIS)

    Yamaguchi, Mami; Anggraini, Sri Ayu; Fujio, Yuki; Breedon, Michael; Plashnitsa, Vladimir V.; Miura, Norio

    2012-01-01

    A selective and sensitive hydrogen (H 2 ) sensor capable of working at a high operating temperature was developed by using a pair of metal-oxide-based SEs formed on a yttria-stabilized zirconia (YSZ) tube, operating as a mixed-potential type sensor. The utilization of SnO 2 (+30 wt.% YSZ) electrode together with NiO-TiO 2 electrode configured as a combined-type sensor, successfully diminished the response of the examined interfering gases (especially propene), while maintaining high response toward H 2 at an operating temperature of 600 °C under humid operating conditions. The developed sensor exhibited quick response to 100 ppm H 2 , as the 90% response time was observed to be 9 s. The sensing performance of the combined-type sensor was barely affected by changes in water vapor concentration within the range of 1–4 vol.%, suggesting the resilience of the sensor to function in realistic working conditions. This sensor exhibited a linear relationship between sensitivity and H 2 concentration on a logarithmic scale.

  18. Remedial Action Plan and site design for stabilization of the inactive uranium mill tailings site at Durango, Colorado: Remedial action selection report

    International Nuclear Information System (INIS)

    1991-12-01

    The uranium mill tailings site near Durango, Colorado, was one of 24 inactive uranium mill sites designated to be remediated by the US Department of Energy (DOE) under the Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). Part of the UMTRCA requires that the US Nuclear Regulatory Commission (NRC) concur with the DOE's Remedial Action Plan (RAP) and certify that the remedial action conducted at the site complies with the standards promulgated by the US Environmental Protection Agency (EPA). Included in the RAP is this Remedial Action Selection Report (RAS), which has been developed to serve a two-fold purpose. First, it describes the activities that have been conducted by the DOE to accomplish remediation and long-term stabilization and control of the radioactive materials at the inactive uranium mill processing site near Durango, Colorado. Secondly, this document and the rest of the RAP, upon concurrence and execution by the DOE, the State of Colorado, and the NRC, become Appendix B of the Cooperative Agreement between the DOE and the State of Colorado

  19. Interconnectivity of macroporous molecularly imprinted polymers fabricated by hydroxyapatite-stabilized Pickering high internal phase emulsions-hydrogels for the selective recognition of protein.

    Science.gov (United States)

    Sun, Yanhua; Li, Yuqing; Xu, Jiangfeng; Huang, Ling; Qiu, Tianyun; Zhong, Shian

    2017-07-01

    Hydroxyapatite hybridized molecularly imprinted polydopamine polymers with selective recognition of bovine hemoglobin (BHb) were successfully prepared via Pickering oil-in-water high internal phase emulsions-hydrogels and molecularly imprinting technique. The emulsions were stabilized by hydroxyapatite of which the wettability was modified by 3-methacryloxypropyltrimethoxysilane. The materials were characterized by SEM, IR and TGA. The results showed that the BHb imprinted polymers based on Pickering hydrogels (Hydro-MIPs) possess macropores ranging from 20μm to 50μm, and their large numbers of amino groups and hydroxyl groups result in a favorable adsorption capacity for BHb. The maximum adsorption capacity of Hydro-MIPs for BHb was 438mg/g, 3.27 times more than that of the non-imprinted polymers (Hydro-NIPs). The results indicated that Hydro-MIPs possessing well-defined hierarchical porous structures exhibited outstanding recognition behavior towards the target protein molecules. This work provided a promising alternative method for the fabrication of polymer materials with tunable and interconnected pores structures for the separation and purification of protein in vitro. Copyright © 2017. Published by Elsevier B.V.

  20. Sexual Assault

    Science.gov (United States)

    ... who is unable to consent. It also includes abusive sexual contact. It can happen to men, women or children. The attacker can be anyone - a current or former partner, a family member, a person in position of power or trust, a friend, an acquaintance, or a ...

  1. Risky sexual

    African Journals Online (AJOL)

    GB

    2012-11-03

    Nov 3, 2012 ... AMONG STUDENTS OF JIMMA UNIVERSITY, ETHIOPIA ... control, substance use, peer pressure, campus and outside ... Author: Gurmesa Tura E- mail: gurmesatura@gmail.com or gurmesa.tura@ju.edu.et .... following substances: alcohol, Khat cigarette, .... leading reason was sexual desire 106(42.9%).

  2. Sexual Violence

    Centers for Disease Control (CDC) Podcasts

    2011-04-04

    This podcast discusses sexual violence - what it is, the long-term health problems it can contribute to, and tips to stop it before it begins.  Created: 4/4/2011 by National Center for Injury Prevention and Control (NCIPC).   Date Released: 4/4/2011.

  3. A simple and selective colorimetric mercury (II) sensing system based on chitosan stabilized gold nanoparticles and 2,6-pyridinedicarboxylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Kun; Siegel, Gene; Tiwari, Ashutosh, E-mail: tiwari@eng.utah.edu

    2017-02-01

    The development of simple and cost-effective methods for the detection and treatment of Hg{sup 2+} in the environment is an important area of research due to the serious health risk that Hg{sup 2+} poses to humans. Colorimetric sensing based on the induced aggregation of nanoparticles is of great interest since it offers a low cost, simple, and relatively rapid procedure, making it perfect for on-site analysis. Herein we report the development of a simple colorimetric sensor for the selective detection and estimation of mercury ions in water, based on chitosan stabilized gold nanoparticles (AuNPs) and 2,6-pyridinedicarboxylic acid (PDA). In the presence of Hg{sup 2+}, PDA induces the aggregation of AuNPs, causing the solution to change colors varying from red to blue, depending on the concentration of Hg{sup 2+}. The formation of aggregated AuNPs in the presence of Hg{sup 2+} was confirmed using transmission electron microscopy (TEM) and UV–Vis spectroscopy. The method exhibits linearity in the range of 300 nM to 5 μM and shows excellent selectivity towards Hg{sup 2+} among seventeen different metal ions and was successfully applied for the detection of Hg{sup 2+} in spiked river water samples. The developed technique is simple and superior to the existing techniques in that it allows detection of Hg{sup 2+} using the naked eye and simple and rapid colorimetric analysis, which eliminates the need for sophisticated instruments and sample preparation methods. - Highlights: • A simple colorimetric method for detection of Hg{sup 2+} in water was proposed. • Au nanoparticles and 2,6-pyridinedicarboxylic acid were used for sensing Hg{sup 2+}. • Sensing mechanisms were demonstrated by TEM and UV–Visible measurements. • It showed the solution color changes from red to blue upon addition of Hg{sup 2+}. • The method selectively detected Hg{sup 2+} among seventeen different metal ions.

  4. Dopamine receptors play distinct roles in sexual behavior expression of rats with a different sexual motivational tone.

    Science.gov (United States)

    Guadarrama-Bazante, Irma L; Canseco-Alba, Ana; Rodríguez-Manzo, Gabriela

    2014-10-01

    Dopamine (DA) plays a central role in the expression of male sexual behavior. The effects of DA-enhancing drugs on copulation seem to vary depending on the dose of the agonist used, the type of DA receptor activated, and the sexual condition of the animals. The aim of the present study was to carry out a systematic analysis of the effects of dopaminergic agonists on the expression of male sexual behavior by sexually competent rats in different sexual motivational states, that is when sexually active (sexually experienced) and when temporarily inhibited (sexually exhausted). To this end, the same doses of the nonselective DA receptor agonist apomorphine, the selective D2-like DA receptor agonist quinpirole, and the selective D1-like DA receptor agonist SKF38393 were injected intraperitoneally to sexually experienced or sexually exhausted male rats and their sexual behavior was recorded. Low apomorphine doses induced expression of sexual behavior in sexually satiated rats, but only reduced the intromission latency of sexually experienced rats. SKF38393 facilitated the expression of sexual behavior by sexually exhausted rats, but not that of sexually experienced males and quinpirole did not exert an effect in both types of animal. In line with these results, the apomorphine-induced reversal of sexual exhaustion was blocked by the D1-like receptor antagonist SCH23390. The data suggest that DA receptors play distinct roles in the expression of sexual behavior by male rats depending on their motivational state and that activation of D1-like receptors promotes the expression of sexual behavior in satiated rats.

  5. Puberty and adolescent sexuality.

    Science.gov (United States)

    Fortenberry, J Dennis

    2013-07-01

    This article is part of a Special Issue "Puberty and Adolescence". Sexuality emerges as a major developmental element of puberty and the adolescent years that follow. However, connecting the sexuality that emerges with puberty and elements of adult sexuality is difficult because much adolescent sexuality research addresses the transition to partnered sexual behaviors (primarily coitus) and consequences such as unplanned pregnancy and sexually transmitted infections. This review proposes a framework of an expanded understanding of puberty and adolescent sexuality from the perspective of four hallmarks of adult sexuality: sexual desire; sexual arousal; sexual behaviors; and, sexual function. This approach thus addresses important gaps in understanding of the ontogeny of sex and the continuum of sexuality development from adolescence through the adult lifespan. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. [Adolescent sexuality].

    Science.gov (United States)

    Calero, Juan del Rey

    2010-01-01

    The social Adolescent features are insecurity, narcissism, eroticism, more impetuosity than reason. 1/3 of adolescents have risk behaviour for health. The pregnancy rate in adolescent are 9/1,000 (11,720, the abort about 50 %). The total abort (2009) were 114,480. Increase the rate of 8,4 (1990) to 14,6/ 1,000 (2009). The sexual education fails. The consulting about contraceptives get pregnancy of the OR 3,2, condom OR 2,7. The adolescent are influenced in his matter: oeer have 70-75 % of influence, mother 30-40 %, father 15 %, for yhe environment and education Cyberspace access to information: 33 % exposed to unwanted sexual materials, 1 in 7 solicited sexual online. The argument have 4 central topic: Morality and Responsibility, Desire (responsibility vs gratification), Danger (fear related to pregnancy and STD/VIH), and Victimization. The prevention of STD: so called safe sex, delayed, and abstinence, Prevention HPV vaccine. The information is not enough, are necessary personal integral formation in values as self control, abstinence, mutual respect, responsibility, reasonable decisions.

  7. Sexuality and Young Children.

    Science.gov (United States)

    Honig, Alice Sterling

    2000-01-01

    Describes normal aspects of sexuality during the early years, including masturbation and children's fanciful sexual ideas. Presents inappropriately mature sexual knowledge as a danger sign of abuse. Discusses whether and what teachers/caregivers should tell children about sexuality, and notes the importance of teaching staff about sexual identity…

  8. Measurement and Design Issues in the Study of Adolescent Sexual Behavior and the Evaluation of Adolescent Sexual Health Behavior Interventions

    Science.gov (United States)

    Young, Michael; Palacios, Rebecca; Penhollow, Tina M.

    2012-01-01

    To improve the quality of research and commentary concerning adolescent sexuality and evaluation of both comprehensive sexuality education and abstinence education programs, this article aims to help readers (1) select appropriate measures to study adolescent sexual behavior, (2) develop appropriate study designs to evaluate adolescent sexual…

  9. Sexual harassment against nurses in Turkey.

    Science.gov (United States)

    Celik, Yusuf; Celik, Sevilay Senol

    2007-01-01

    To identify the prevalence and sources of sexual harassment against nurses in Turkey, its consequences, and factors affecting harassment experiences. Descriptive survey. Participants (N=622) were selected from nurses working in eight Ministry of Health hospitals in Turkey. Participants were surveyed with a Sexual Harassment Questionnaire, consisting of the sociodemographic characteristics of participants, types of sexual harassment, sources, feelings, ramifications, and ways to cope with sexual harassment behaviors. Frequency and percentage distributions, chi-square, and logistic regression were used for data analysis. The results showed 37.1% of participants had been harassed sexually. Physicians were identified as the primary instigators of sexual harassment. The most common reactions against harassers were anger and fear; frequently reported negative effects of sexual harassment were disturbed mental health function, decline in job performance, and headache. "Did nothing" was the coping method used most commonly by the nurses. About 80% of sexually harassed nurses did not report the incident of sexual harassment to hospital administration. The lower working status and power of nurses in the workplace, poor working conditions in healthcare settings, and insufficient administrative mechanisms, including the present law and regulations against sexual harassers, were identified as important factors in the work environment in Turkey.

  10. BODY SIZE AND HAREM SIZE IN MALE RED-WINGED BLACKBIRDS: MANIPULATING SELECTION WITH SEX-SPECIFIC FEEDERS.

    Science.gov (United States)

    Rohwer, Sievert; Langston, Nancy; Gori, Dave

    1996-10-01

    We experimentally manipulated the strength of selection in the field on red-winged blackbirds (Agelaius phoeniceus) to test hypotheses about contrasting selective forces that favor either large or small males in sexually size dimorphic birds. Selander (1972) argued that sexual selection favors larger males, while survival selection eventually stabilizes male size because larger males do not survive as well as smaller males during harsh winters. Searcy (1979a) proposed instead that sexual selection may be self limiting: male size might be stabilized not by overwinter mortality, but by breeding-season sexual selection that favors smaller males. Under conditions of energetic stress, smaller males should be able to display more and thus achieve higher reproductive success. Using feeders that provisioned males or females but not both, we produced conditions that mimicked the extremes of natural conditions. We found experimental support for the hypothesis that when food is abundant, sexual selection favors larger males. But even under conditions of severe energetic stress, smaller males did not gain larger harems, as the self-limiting hypothesis predicted. Larger males were more energetically stressed than smaller males, but in ways that affected their future reproductive output rather than their current reproductive performance. Stressed males that returned had smaller wings and tails than those that did not return; among returning stressed males, relative harem sizes were inversely related to wing and tail length. Thus, male body size may be stabilized not by survival costs during the non-breeding season, nor by energetic costs during the breeding season, but by costs of future reproduction that larger males pay for their increased breeding-season effort. © 1996 The Society for the Study of Evolution.

  11. Teachers' Perspectives on Sexual and Reproductive Health ...

    African Journals Online (AJOL)

    AJRH Managing Editor

    While school-based sexual and reproductive health interventions for in-school adolescents is widely recognized .... selection of the schools in Ile-Ife and Ilesa through .... abortion, which had led to deaths of some female ..... Indian journal of.

  12. Antidepressant induced sexual dysfunction Part 1: epidemiology ...

    African Journals Online (AJOL)

    Adele

    Abstract. Sexual dysfunction is a common side effect of treatment with antidepressants, particularly those with a predominantly .... free of serotonergic effects or have highly selective receptor .... received little attention in the current literature.

  13. Stabilized radiographic scanning agent

    International Nuclear Information System (INIS)

    Fawzi, M.B.

    1979-01-01

    A stable composition useful in preparation of technetium-99m-based radiographic scanning agents has been developed. The composition contains a stabilizing amount of gentisate stabilizer selected from gentisic acid and its soluble pharmaceutically-acceptable salts and esthers. (E.G.)

  14. Female Sexual Dysfunction

    Science.gov (United States)

    ... Overview Persistent, recurrent problems with sexual response, desire, orgasm or pain — that distress you or strain your ... You have persistent or recurrent difficulty in achieving orgasm after sufficient sexual arousal and ongoing stimulation. Sexual ...

  15. Rethinking Sexual Citizenship.

    Science.gov (United States)

    Richardson, Diane

    2017-04-01

    Over the last two decades sexuality has emerged as a key theme in debates about citizenship, leading to the development of the concept of sexual citizenship. This article reviews this literature and identifies four main areas of critical framing: work that contests the significance of sexuality to citizenship; critiques that focus on the possibilities and limitations of mobilising the language of citizenship in sexual politics; analyses of sexual citizenship in relation to nationalisms and border making; and literature that critically examines western constructions of sexuality and sexual politics underpinning understandings of sexual citizenship. In order to progress the field theoretically, the article seeks to extend critiques of sexual citizenship focusing on two key aspects of its construction: the sexual citizen-subject and spaces of sexual citizenship. It argues for a critical rethink that encompasses a de-centring of a 'western-centric' focus in order to advance understandings of how sexual citizenship operates both in the Global North and South.

  16. Dating and Sexual Feelings

    Science.gov (United States)

    ... Home Body Your sexuality Dating and sexual feelings Dating and sexual feelings Thinking about romance, starting to ... you learn how to stay healthy and strong. Dating older guys top If you date someone even ...

  17. Effects of Sexuality Information on Sexual Behavior and Control of ...

    African Journals Online (AJOL)

    There was significant correlation between knowledge of sexuality and sexual ... Conclusion: It is recommended that instructors on sexuality education be ... youths facts of sexuality, contraception and sexually transmitted diseases to reduce the ...

  18. Sexual Health

    Directory of Open Access Journals (Sweden)

    Dr. Christine Boyce

    2009-04-01

    Full Text Available This month two general practitioners (GPs describe their approach to sexual health consultations.The issue of a sexually active adolescent demonstrates some differences in legislation pertaining tothe requirement to involve the authorities, although in essence the young person can expect thesame response from these practitioners in two different health care systems. On the other hand apatient at risk of sexually transmitted infections is more likely to be referred to a specialistGenitourinary clinic in the UK although the protocols for screening and education are largely similar.Equally patients who are HIV positive can expect to receive the bulk of their care from specialistclinics in both countries.Midwives are the main stay of antenatal services in Australia and the UK with general practitionersminimally involved in routine cases. Also home births are a negigible proportion of all deliveries ineither country. When patients opt for a home birth our authors expressed the view that GPsgenerally do not have the skills or experience to be the main health professional in attendance.Therefore such births are primarily managed by midwives as the key health care professional. Thefocus of General practitioners is primarily to ensure that the patient is making an informed decisionabout delivering her baby at home. The GP is therefore still in an influential position to assist thewoman in making a decision about where to give birth. As a point of difference in Australia a homebirth would result in out of pocket expences for the mother.The views expressed below are those of the authors and do not necessarily reflect health policy orpractice elsewhere in their countries. However we believe they offer an interesting perspective ontheir health care systems and commend the article to our readers.Please

  19. Sexually antagonistic coevolution for sexual harassment can act as a barrier to further invasions by parthenogenesis.

    Science.gov (United States)

    Kawatsu, Kazutaka

    2013-02-01

    The assumption of a twofold cost of sex not only complicates the maintenance of sex but also sets conditions for sexual conflict: in organisms with the twofold cost, males often sexually harass females. Sexual harassment is detrimental to female fitness and thus might help maintain sexual populations if male harassment inflicts a harsher cost on parthenogens than on sexual females (asymmetric harassment cost). However, the generality of this concept is now considered doubtful because selective harassment of parthenogens results in loss of mating opportunities for males. Using three mathematical models, I show here that sexual harassment still can impose the asymmetric cost on parthenogens. First, I apply the Lotka-Volterra model to show the degree of asymmetric harassment cost that permits sex to be maintained stably in the population. Second, using adaptive dynamics, I examine whether sexually antagonistic coevolution for sexual harassment, which occurs only in sexual populations, can promote the asymmetric harassment cost. Finally, an individual-based model, which assumes a spatial structure unlike that in the other two, demonstrates that the asymmetric evolution of harassment cost prevents further invasions of parthenogens from different patches into sexual lineages; these mechanisms may account for allopatric distributions of sexual and parthenogenetic lineages as well as the maintenance of sex.

  20. Sexuality education in Brazil.

    Science.gov (United States)

    Suplicy, M

    1994-01-01

    The development of a comprehensive program of sex education in Brazilian schools is described in the context of Brazil's culture and traditions such as the Carnival. The influence of Catholicism is explored as is the effect of the behavioral restrictions called for by scientists concerned about sexually transmitted diseases. The Brazilian response to homosexuality is described, and the emergence of a public discussion of sexuality in the media is traced. It is noted that improvements in the status of women have been held in check by a public ridicule of feminism and by the strength of the traditional patriarchal structures which dominate the culture. With this picture given of how the issue of sexuality fits into Brazilian life, the 1980s initiative on the part of the Work and Research Group for Sex Education is described. Opposition to this effort has largely taken the form of passive resistance; even the Catholic Church has not officially protested the sex education program. Details are provided about 1) the selection of teachers, teacher training, and weekly supervisory teacher meetings; 2) the way in which parental permission for student participation was gained; 3) the implementation of the program; 4) the successes achieved; and 5) the difficulties encountered. Finally, it is noted that plans were made to expand the sex education project from the Sao Paulo area to 6 additional large cities in 1994. Also planned is the publication of the Brazilian Guidelines for Comprehensive Sexuality which will explain the sex education methodology and be extremely valuable in the establishment of new projects.

  1. A Cultural Sexuality or a Sexual Culture?

    NARCIS (Netherlands)

    Vandermeersch, Patrick

    1990-01-01

    P. Vandermeersch, A Cultural Sexuality or a Sexual Culture? In: F. VAN DE VIJVER & G. HUTSCHEMAEKERS (ed.), The Investigation of Culture. Current Issues in Cultural Psychology, Tilburg, Tilburg University Press, 1990, 43-58.

  2. Effectiveness of the Sexual Attitude Restructuring Curriculum amongst Taiwanese Graduate Students

    Science.gov (United States)

    Lin, Yi-Li; Lin, Yen-Chin

    2018-01-01

    This article discusses the effectiveness of the Sexual Attitude Restructuring (SAR) curriculum in developing positive sexual attitudes amongst Taiwanese graduate students in human sexuality. Through purposive sampling, 32 graduate students in human sexuality were selected to participate in the study. Before and after providing participants with a…

  3. Multidimensional sexual perfectionism.

    Science.gov (United States)

    Stoeber, Joachim; Harvey, Laura N; Almeida, Isabel; Lyons, Emma

    2013-11-01

    Perfectionism is a multidimensional personality characteristic that can affect all areas of life. This article presents the first systematic investigation of multidimensional perfectionism in the domain of sexuality exploring the unique relationships that different forms of sexual perfectionism show with positive and negative aspects of sexuality. A sample of 272 university students (52 male, 220 female) completed measures of four forms of sexual perfectionism: self-oriented, partner-oriented, partner-prescribed, and socially prescribed. In addition, they completed measures of sexual esteem, sexual self-efficacy, sexual optimism, sex life satisfaction (capturing positive aspects of sexuality) and sexual problem self-blame, sexual anxiety, sexual depression, and negative sexual perfectionism cognitions during sex (capturing negative aspects). Results showed unique patterns of relationships for the four forms of sexual perfectionism, suggesting that partner-prescribed and socially prescribed sexual perfectionism are maladaptive forms of sexual perfectionism associated with negative aspects of sexuality whereas self-oriented and partner-oriented sexual perfectionism emerged as ambivalent forms associated with positive and negative aspects.

  4. Conceptual model of male military sexual trauma.

    Science.gov (United States)

    Elder, William B; Domino, Jessica L; Rentz, Timothy O; Mata-Galán, Emma L

    2017-08-01

    Male sexual trauma is understudied, leaving much to be known about the unique mental health needs of male survivors. This study examined veteran men's perceptions of the effects of military sexual trauma. Military sexual trauma was defined as physically forced, verbally coerced, or substance-incapacitated acts experienced during military service. Interviews were conducted with 21 male veterans who reported experiencing military sexual trauma. Data were drawn together using a grounded theory methodology. Three categories emerged from data analysis, including (a) types of military sexual trauma (being touched in a sexual way against their will [N = 18]; sexual remarks directed at them [N = 15]; being physically forced to have sex [N = 13]); (b) negative life effects (difficulty trusting others [N = 18]; fear of abandonment [N = 17]; substance use [N = 13]; fear of interpersonal violence [N = 12]; conduct and vocational problems [N = 11]; irritability/aggression [N = 8]; insecurity about sexual performance [N = 8]; difficulty managing anger [N = 8]); and (c) posttraumatic growth (N = 15). Results from this study suggest sexual trauma in the military context may affect systems of self-organization, specifically problems in affective, self-concept, and relational domains, similar to symptoms of those who have experienced prolonged traumatic stressors. This model can be used by clinicians to select treatments that specifically target these symptoms and promote posttraumatic growth. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  5. Cable Stability

    Energy Technology Data Exchange (ETDEWEB)

    Bottura, L [European Organization for Nuclear Research, Geneva (Switzerland)

    2014-07-01

    Superconductor stability is at the core of the design of any successful cable and magnet application. This chapter reviews the initial understanding of the stability mechanism, and reviews matters of importance for stability such as the nature and magnitude of the perturbation spectrum and the cooling mechanisms. Various stability strategies are studied, providing criteria that depend on the desired design and operating conditions.

  6. Sexual Orientation (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Sexual Orientation KidsHealth / For Parents / Sexual Orientation What's in this ... orientation is part of that process. What Is Sexual Orientation? The term sexual orientation refers to the gender ( ...

  7. Addressing Sexual Harassment

    Science.gov (United States)

    Young, Ellie L.; Ashbaker, Betty Y.

    2008-01-01

    This article discusses ways on how to address the problem of sexual harassment in schools. Sexual harassment--simply defined as any unwanted and unwelcome sexual behavior--is a sensitive topic. Merely providing students, parents, and staff members with information about the school's sexual harassment policy is insufficient; schools must take…

  8. Sexuality education in Malaysia: perceived issues and barriers by professionals.

    Science.gov (United States)

    Khalaf, Zahra Fazli; Low, Wah Yun; Merghati-Khoei, Effat; Ghorbani, Behzad

    2014-07-01

    This research explored the perspectives of Malaysian professionals on the issues and barriers affecting the implementation of sexuality education in Malaysia. This qualitative study involved in-depth interviews with 15 key professionals working in the field of sexuality and reproductive health in Malaysia. Thematic analysis was selected to analyze data. Barriers to sexuality education were perceived from 5 aspects: feasibility, acceptability, accountability, strategies, and community unawareness. Respondents believed that implementing national sexuality education is a time-consuming project. They regarded Malaysian multicultural society as a barrier to national sexuality education, and they believed that school-based sexuality education is not easily accomplished in Malaysia; also abstinence-only policy restricts the access of young people to accurate information. Lack of community involvement was perceived as a key concern to sexuality education. Campaigning to promote awareness of families, teachers, community leaders, and policy makers are recommended to help establishing national sexuality education in Malaysia. © 2014 APJPH.

  9. Sexual Functioning After Childhood Abuse: The Influence of Post-Traumatic Stress Disorder and Trauma Exposure.

    Science.gov (United States)

    Bornefeld-Ettmann, Pia; Steil, Regina; Lieberz, Klara A; Bohus, Martin; Rausch, Sophie; Herzog, Julia; Priebe, Kathlen; Fydrich, Thomas; Müller-Engelmann, Meike

    2018-04-01

    is the first comparing PTSD patients and TC with healthy women with regards to sexual functioning. Limitations are selection and size of the samples, the assessment of sexual functioning by self-report measures only, and lack of consideration of other potentially relevant factors influencing sexuality. The findings suggest that the experience of sexual abuse does not necessarily lead to sexual impairment, whereas comparably low levels of sexual functioning seem to be prominent in PTSD patients after CSA. Further research is needed on how to improve treatment for this patient group. Bornefeld-Ettmann P, Steil R, Lieberz KA, et al. Sexual Functioning After Childhood Abuse: The Influence of Post-Traumatic Stress Disorder and Trauma Exposure. J Sex Med 2018;15:529-538. Copyright © 2018 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

  10. Sexual risk taking behaviour

    DEFF Research Database (Denmark)

    Buttmann, Nina; Nielsen, Ann; Munk, Christian

    2011-01-01

    Sexual habits and risky sexual behaviour strongly affect public health. Available data indicate that sexually transmitted infections are increasing in many EU countries. Changes in the epidemiology of sexually transmitted diseases across Europe are among other factors suggested to be driven by ch...... by changes in sexual behaviour patterns. The purpose of our study is to assess the occurrence of risky behaviour in men aged 18-45 years from the general population. Furthermore, we aim to examine factors associated with risky sexual behaviour.......Sexual habits and risky sexual behaviour strongly affect public health. Available data indicate that sexually transmitted infections are increasing in many EU countries. Changes in the epidemiology of sexually transmitted diseases across Europe are among other factors suggested to be driven...

  11. Cryptic sexual size dimorphism in Malagasy plovers Charadrius spp ...

    African Journals Online (AJOL)

    Taken together, our work reports SSD in small African plovers that exhibit monomorphic plumage, and we propose that SSD may be more common than currently acknowledged; we term this 'cryptic sexual size dimorphism'. Our results also suggest sexual selection and/or natural selection exert different pressures on body ...

  12. Sexual and social competition: broadening perspectives by defining female roles.

    Science.gov (United States)

    Rubenstein, Dustin R

    2012-08-19

    Males figured more prominently than females in Darwin's view of sexual selection. He considered female choice of secondary importance to male-male competition as a mechanism to explain the evolution of male ornaments and armaments. Fisher later demonstrated the importance of female choice in driving male trait evolution, but his ideas were largely ignored for decades. As sexual selection came to embrace the notions of parent-offspring and sexual conflict, and experimental tests of female choice showed promise, females began to feature more prominently in the framework of sexual selection theory. Recent debate over this theory has centred around the role of females, not only over the question of choice, but also over female-female competition. Whereas some have called for expanding the sexual selection framework to encompass all forms of female-female competition, others have called for subsuming sexual selection within a broader framework of social selection, or replacing it altogether. Still others have argued for linking sexual selection more clearly to other evolutionary theories such as kin selection. Rather than simply debating terminology, we must take a broader view of the general processes that lead to trait evolution in both sexes by clearly defining the roles that females play in the process, and by focusing on intra- and inter-sexual interactions in males and females.

  13. Buffer or Brake? The Role of Sexuality-Specific Parenting in Adolescents’ Sexualized Media Consumption and Sexual Development

    NARCIS (Netherlands)

    G.J. Overbeek (Geertjan); van de Bongardt, D. (Daphne); Baams, L. (Laura)

    2018-01-01

    textabstractOne main source of sexual socialization lies within family interactions. Especially sexuality-specific parenting may determine adolescents’ sexual development—adolescents’ sexual behavior and sexual risk behavior, sexualized media consumption and permissive sexual attitudes—to a

  14. Buffer or Brake? The Role of Sexuality-Specific Parenting in Adolescents’ Sexualized Media Consumption and Sexual Development

    NARCIS (Netherlands)

    Overbeek, Geertjan; van de Bongardt, Daphne; Baams, Laura

    2018-01-01

    One main source of sexual socialization lies within family interactions. Especially sexuality-specific parenting may determine adolescents’ sexual development—adolescents’ sexual behavior and sexual risk behavior, sexualized media consumption and permissive sexual attitudes—to a significant extent,

  15. Sexual Function Across Aging.

    Science.gov (United States)

    Clayton, Anita H; Harsh, Veronica

    2016-03-01

    Women experience multiple changes in social and reproductive statuses across the life span which can affect sexual functioning. Various phases of the sexual response cycle may be impacted and can lead to sexual dysfunction. Screening for sexual problems and consideration of contributing factors such as neurobiology, reproductive life events, medical problems, medication use, and depression can help guide appropriate treatment and thereby improve the sexual functioning and quality of life of affected women. Treatment options include psychotropic medications, hormone therapy, and psychotherapy.

  16. Sexuality and Islam.

    Science.gov (United States)

    Dialmy, Abdessamad

    2010-06-01

    This paper deals with three major questions: (1) What are the sexual norms defined by the sacred texts (Koran and Sunna)? (2) What are the sexual practices currently observed among Moslems? (3) To which extent are current sexual practices of Moslems dissociated from Islamic sexual norms? Sexual standards in Islam are paradoxical: on the one hand, they allow and actually are an enticement to the exercise of sexuality but, on the other hand, they discriminate between male and female sexuality, between marital and pre- or extramarital sexuality, and between heterosexuality and homosexuality. Men are given more rights with regard to the expression of their sexuality; women are forbidden to have extramarital sex (with their slaves) and both genders to have homosexual relationships. The combination of these paradoxical standards with modernisation leads to the current back and forth swing of sexual practices between repression and openness. Partial modernisation leads to greater sexual tolerance. But restrictive sexual standards have gathered strength and have become idealised as a result of the current radicalisation of Islam. This swing of the pendulum between repression and openness is illustrated by phenomena such as public harassment, premarital sexuality, female pleasure, prostitution, and homosexuality. Currently, Islam is not any more the only reference which provides guidance concerning sexual practices but secularisation of sexual laws is still politically unthinkable today. So the only solution is to achieve reform in the name of Islam, through the reinterpretation of repressive holy texts.

  17. Helping Clinicians Prevent Pregnancy among Sexually Active Adolescents: U.S. Medical Eligibility Criteria for Contraceptive Use and U.S. Selected Practice Recommendations for Contraceptive Use.

    Science.gov (United States)

    Godfrey, Emily M

    2015-08-01

    The United States has made substantial progress in reducing teenage birth rates in recent decades, but rates remain high. Teen pregnancy can increase the risk of poor health outcomes and lead to decreased educational attainment, increased poverty, and welfare use, as well as increased cost to taxpayers. One of the most effective ways to prevent teenage pregnancy is through the use of effective birth control methods. The Centers for Disease Control (CDC) and Prevention has made the prevention of teenage pregnancy 1 of its 10 winnable battles. The CDC has released 2 evidence-based clinical guideline documents regarding contraceptive use for adolescents and adults. The first guideline, US Medical Eligibility Criteria for Contraceptive Use, 2010, helps clinicians recognize when a contraceptive method may not be safe to use for a particular adolescent but also when not to withhold a contraceptive method that is safe to use. The second document, US Selected Practice Recommendations for Contraceptive Use, 2013, provides guidance for how to use contraceptive methods safely and effectively once they are deemed safe. Health care providers are encouraged to use these documents to provide safe and effective contraceptive care to patients seeking family planning, including adolescents. Copyright © 2015 North American Society for Pediatric and Adolescent Gynecology. All rights reserved.

  18. Sexual dimorphism of the incidence of significant relationships between selected parameters of feet and characteristics of trunk in adolescents aged 14 – 18 years

    Directory of Open Access Journals (Sweden)

    Mirosław Mrozkowiak

    2018-03-01

    Full Text Available Summary Introduction. Symmetry, asymmetry, mutual relationships and concomitance have become a subject of interest of numerous researchers. The analysis of the findings obtained in the own study conducted among adolescents aged 14-18 years revealed an incidental nature and randomness of the distribution of significant correlations in each age and gender range, which made it impossible to show any regularities or dependencies between the measured parameters. Material and method. The examinations carried out in the group of teenagers aged 14 to 18 years recorded 2,343 observations, including 1,148 girls and 1,195 boys, concerning the size of 89 parameters describing trunk and feet. The station for an assessment of selected features using the photogrammetric method consisted of a computer, a card, software, a display monitor, a printer and a projection-reception device with a camera.     Findings 1. The number of feet parameters revealing significant relationships with trunk parameters which differentiated the female gender from the male one was greater; likewise, the features in women revealed a more frequent relationship. Additionally, female sex was differentiated by morphological traits, the abnormal positioning of toes and the longitudinal arch of feet. 2. The number of trunk parameters correlating with foot parameters was observed to be bigger in the female gender than in the male one. The parameters in female subjects showed more relationships and the parameters which differentiated female sex included the frontal plane and the sagittal plane to a lesser extent, whereas male gender was characterized by the sagittal plane.

  19. The impact of Parkinson disease on patients' sexuality and relationship.

    Science.gov (United States)

    Buhmann, C; Dogac, S; Vettorazzi, E; Hidding, U; Gerloff, C; Jürgens, T P

    2017-08-01

    This study aimed at examining the impact of Parkinson disease (PD) on patients' sexuality and relationship and to evaluate gender-specific differences. Using a standardized questionnaire on sexual functioning in chronic diseases (SFCE), the impact of PD diagnosis on 38 domains of sexuality before and since PD diagnosis was evaluated retrospectively in 53 consecutive patients in a relationship. Changes in self-assessed ratings on a four-point Likert scale were determined for all patients. In addition, gender-specific differences and the influence of age, depression (BDI-II), medication, disease severity and disease duration on domains of the SFCE were calculated. The importance of non-sexual relational aspects, such as talking about feelings or tenderness increased for both genders after PD diagnosis, especially in women. Sexual function, such as frequency of intercourse, sexual arousal, subjective abnormal sexual fantasies or sexual satisfaction deteriorated in both genders, especially in men. Some sexual aspects improved in women but worsened in men after PD diagnosis. This includes frequency of orgasm dysfunction, fear not to fulfill sexual expectations of the partner, avoidance of sexual acts, withdrawal from relationship, increase of thoughts about divorce, or increase of dissatisfaction with sexuality and relationship. With age, thoughts about divorce declined. With disease duration, frequency of tenderness with the partner increased. Depression unexpectedly correlated with higher frequency of intercourse. Dopaminergic dosage influenced stability of the relationship negatively. PD influences patients' sexuality negatively, independently of age, disease duration or disease severity and men show greater sexual dysfunction and impairment of their sexual relationship than women.

  20. Remedial action plan and site design for stabilization of the inactive uranium mill tailings sites at Slick Rock, Colorado: Remedial Action Selection Report. Preliminary final

    Energy Technology Data Exchange (ETDEWEB)

    1994-03-01

    This proposed remedial action plan incorporates the results of detailed investigation of geologic, geomorphic, and seismic conditions at the proposed disposal site. The proposed remedial action will consist of relocating the uranium mill tailings, contaminated vicinity property materials, demolition debris, and windblown/waterborne materials to a permanent repository at the proposed Burro Canyon disposal cell. The proposed disposal site will be geomorphically stable. Seismic design parameters were developed for the geotechnical analyses of the proposed cell. Cell stability was analyzed to ensure long-term performance of the disposal cell in meeting design standards, including slope stability, settlement, and liquefaction potential. The proposed cell cover and erosion protection features were also analyzed and designed to protect the RRM (residual radioactive materials) against surface water and wind erosion. The location of the proposed cell precludes the need for permanent drainage or interceptor ditches. Rock to be used on the cell top-, side-, and toeslopes was sized to withstand probable maximum precipitation events.

  1. A methodological approach to study the stability of selected watercolours for painting reintegration, through reflectance spectrophotometry, Fourier transform infrared spectroscopy and hyperspectral imaging

    Science.gov (United States)

    Pelosi, Claudia; Capobianco, Giuseppe; Agresti, Giorgia; Bonifazi, Giuseppe; Morresi, Fabio; Rossi, Sara; Santamaria, Ulderico; Serranti, Silvia

    2018-06-01

    The aim of this work is to investigate the stability to simulated solar radiation of some paintings samples through a new methodological approach adopting non-invasive spectroscopic techniques. In particular, commercial watercolours and iron oxide based pigments were used, these last ones being prepared for the experimental by gum Arabic in order to propose a possible substitute for traditional reintegration materials. Reflectance spectrophotometry in the visible range and Hyperspectral Imaging in the short wave infrared were chosen as non-invasive techniques for evaluation the stability to irradiation of the chosen pigments. These were studied before and after artificial ageing procedure performed in Solar Box chamber under controlled conditions. Data were treated and elaborated in order to evaluate the sensitivity of the chosen techniques in identifying the variations on paint layers, induced by photo-degradation, before they could be observed by eye. Furthermore a supervised classification method for monitoring the painted surface changes adopting a multivariate approach was successfully applied.

  2. Child sexual abuse

    International Nuclear Information System (INIS)

    Khalid, N.

    2001-01-01

    Background: Child sexual abuse with significant impact on victim's physical, mental and social health has now been recognized as existing on an appreciable scale worldwide. Diversity of opinions exist about the concept, types, prevalence and repercussions along with a paucity of systematic and scientific work in the developing world including Pakistan. Objective: This paper aims at reviewing the literature for clarification of concept, update of estimates and correlates, and to identify lines for future research. Data sources: The literature was search through BMJ-Medline for international data, supplemented by local data through CPSP-MEDLIP service. The search term child sexual abuse with associated sub-heads were used. No constraint of time period, publication type or source applied except english Language version Comparative findings: Wide variations identified in conceptual boundaries with consequent impact on prevalence estimates. Agreement found for its existence as an international problem with rates ranging from 7% - 36% for women and 3% - 29% for men. Female abused 1.5-3 times more than male with exponential high rates in age group 3-6 years and 8-11 years. In 2/3 cases the perpetrator identified belonged to nuclear or extended family. Significant association exists with early onset of psychiatric ailments like substance abuse, eating disorders, personality disorders, dissociative disorders and depression. Conclusion and Suggestion: The need for extensive research studies in immense in developing countries like Pakistan where environmental circumstances suggest its presence at rates higher than the identified elsewhere. In addition to facilitate awareness and perhaps to clarify the concept as well as the prevalence of child sexual abuse researchers need to select methodologies and instruments with international comparison in mind. (author)

  3. Toward Rational Design of Cu/SSZ-13 Selective Catalytic Reduction Catalysts: Implications from Atomic-Level Understanding of Hydrothermal Stability

    Energy Technology Data Exchange (ETDEWEB)

    Song, James [Institute; The; amp, Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, P.O. Box 646515, Pullman, Washington 99164, United States; Wang, Yilin [Institute; Walter, Eric D. [Environmental; Washton, Nancy M. [Environmental; Mei, Donghai [Institute; Kovarik, Libor [Environmental; Engelhard, Mark H. [Environmental; Prodinger, Sebastian [Institute; Wang, Yong [Institute; The; amp, Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, P.O. Box 646515, Pullman, Washington 99164, United States; Peden, Charles H. F. [Institute; Gao, Feng [Institute

    2017-11-03

    The hydrothermal stability of Cu/SSZ-13 SCR catalysts has been extensively studied, yet atomic level understanding of changes to the zeolite support and the Cu active sites during hydrothermal aging are still lacking. In this work, via the utilization of spectroscopic methods including solid-state 27Al and 29Si NMR, EPR, DRIFTS, and XPS, together with imaging and elemental mapping using STEM, detailed kinetic analyses, and theoretical calculations with DFT, various Cu species, including two types of isolated active sites and CuOx clusters, were precisely quantified for samples hydrothermally aged under varying conditions. This quantification convincingly confirms the exceptional hydrothermal stability of isolated Cu2+-2Z sites, and the gradual conversion of [Cu(OH)]+-Z to CuOx clusters with increasing aging severity. This stability difference is rationalized from the hydrolysis activation barrier difference between the two isolated sites via DFT. Discussions are provided on the nature of the CuOx clusters, and their possible detrimental roles on catalyst stability. Finally, a few rational design principles for Cu/SSZ-13 are derived rigorously from the atomic-level understanding of this catalyst obtained here. The authors gratefully acknowledge the US Department of Energy (DOE), Energy Efficiency and Renewable Energy, Vehicle Technologies Office for the support of this work. Computing time was granted by a user proposal at the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL) and by the National Energy Research Scientific Computing Center (NERSC). The experimental studies described in this paper were performed in the EMSL, a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). PNNL is operated for the US DOE by Battelle.

  4. "Children are sexually innocent": Iranian parents' understanding of children's sexuality.

    Science.gov (United States)

    Merghati-Khoei, Effat; Abolghasemi, Naria; Smith, Thomas G

    2014-04-01

    Sexuality education (SE) is hotly contested in the West and there is much abstinence-only education; however, it remains controversial in a variety of contexts, including in Iran. The lack of consensus about children's SE in Muslim societies obliges us to explore different aspects of this topic systematically. The qualitative research presented here was about how Iranian parents perceived children's sexuality. Data from parents of 26 children were collected during four focus group sessions. Informants were selected from Area 5 in West Tehran. This area included 72 primary schools for girls and 82 for boys. The sessions were facilitated by using a semi-structured focus group guide. Content analysis was adopted using combined free and analytical coding to reduce data, to extract meanings, and to categorize domains. One of the three main domains identified, family management of child sexuality, is comprised of the following: (1) understanding of child sexuality, (2) family rules, (3) parent-child interactions, and (4) opposite sex interactions. Parental misinformation, accumulated myths, and ignorance about children's sexual development were evident. Strict family rules and a lack of consistent policy and instruction for SE were also identified. Parents said they were neither well-prepared nor competent to educate their children about sexuality. In fact, a majority of mothers raised "incompetence" as an important determinant in their own parent-child interactions. Societal changes as well as children's socialization patterns have forced parents to accept their children's opposite sex friendships as a reality. Results suggest a community need for developing comprehensive and culturally sensitive SE for schools and parental use.

  5. Biology of Sexual Dysfunction

    Directory of Open Access Journals (Sweden)

    Anil Kumar Mysore Nagaraj

    2009-05-01

    Full Text Available Sexual activity is a multifaceted activity, involving complex interactions between the nervous system, the endocrine system, the vascular system and a variety of structures that are instrumental in sexual excitement, intercourse and satisfaction. Sexual function has three components i.e., desire, arousal and orgasm. Many sexual dysfunctions can be categorized according to the phase of sexual response that is affected. In actual clinical practice however, sexual desire, arousal and orgasmic difficulties more often than not coexist, suggesting an integration of phases. Sexual dysfunction can result from a wide variety of psychological and physiological causes including derangements in the levels of sex hormones and neurotrensmitters. This review deals with the biology of different phases of sexual function as well as implications of hormones and neurotransmitters in sexual dysfunction

  6. Sexual Narcissism and the Perpetration of Sexual Aggression

    Science.gov (United States)

    McNulty, James K.

    2014-01-01

    Despite indirect evidence linking narcissism to sexual aggression, studies directly examining this relationship have yielded inconsistent results. Likely contributing to such inconsistencies, prior research has used global measures of narcissism not sensitive to whether the components of narcissism are activated in sexual versus non-sexual domains. The current research avoided such problems by using a measure of sexual narcissism to predict sexual aggression. In a sample of 299 men and women, Study 1 validated the Sexual Narcissism Scale, a new sexuality research instrument with four subscales—Sexual Exploitation, Sexual Entitlement, Low Sexual Empathy, and Sexual Skill. Then, in a sample of 378 men, Study 2 demonstrated that sexual narcissism was associated with reports of the frequency of sexual aggression, three specific types of sexual aggression (unwanted sexual contact, sexual coercion, and attempted/completed rape), and the likelihood of future sexual aggression. Notably, global narcissism was unrelated to all indices of sexual aggression when sexual narcissism was controlled. That sexual narcissism outperformed global assessments of narcissism to account for variance in sexual aggression suggests that future research may benefit by examining whether sexual narcissism and other sexual-situation-specific measurements of personality can similarly provide a more valid test of the association between personality and other sexual behaviors and outcomes (e.g., contraceptive use, infidelity, sexual satisfaction). PMID:19130204

  7. Sexual narcissism and the perpetration of sexual aggression.

    Science.gov (United States)

    Widman, Laura; McNulty, James K

    2010-08-01

    Despite indirect evidence linking narcissism to sexual aggression, studies directly examining this relationship have yielded inconsistent results. Likely contributing to such inconsistencies, prior research has used global measures of narcissism not sensitive to whether the components of narcissism are activated in sexual versus non-sexual domains. The current research avoided such problems by using a measure of sexual narcissism to predict sexual aggression. In a sample of 299 men and women, Study 1 validated the Sexual Narcissism Scale, a new sexuality research instrument with four subscales-Sexual Exploitation, Sexual Entitlement, Low Sexual Empathy, and Sexual Skill. Then, in a sample of 378 men, Study 2 demonstrated that sexual narcissism was associated with reports of the frequency of sexual aggression, three specific types of sexual aggression (unwanted sexual contact, sexual coercion, and attempted/completed rape), and the likelihood of future sexual aggression. Notably, global narcissism was unrelated to all indices of sexual aggression when sexual narcissism was controlled. That sexual narcissism outperformed global assessments of narcissism to account for variance in sexual aggression suggests that future research may benefit by examining whether sexual narcissism and other sexual-situation-specific measurements of personality can similarly provide a more valid test of the association between personality and other sexual behaviors and outcomes (e.g., contraceptive use, infidelity, sexual satisfaction).

  8. Correlates of sexual initiation among European adolescents

    Science.gov (United States)

    Carli, Vladimir; Hadlaczky, Gergö; Sarchiapone, Marco; Apter, Alan; Balazs, Judit; Banzer, Raphaela; Bobes, Julio; Brunner, Romuald; Cosman, Doina; Farkas, Luca; Haring, Christian; Hoven, Christina W.; Kaess, Michael; Kahn, Jean Pierre; McMahon, Elaine; Postuvan, Vita; Sisask, Merike; Värnik, Airi; Zadravec Sedivy, Nusa; Wasserman, Danuta

    2018-01-01

    Background Sexuality is a physiological component of adolescent development, though early initiation is associated with reproductive health risk. This study aimed at identifying correlates and predictors of sexual initiation in a large multinational cohort of European adolescents. Methods A questionnaire addressing socio-demographics, behaviours, mental health and sexual activity, was delivered to 11,110 adolescents recruited from 168 randomly selected schools in 10 European countries between 2009 and 2011. A follow-up questionnaire was delivered after 12 months. The longitudinal association of baseline risk behaviors, psychological attributes and contextual vulnerabilities, with sexual initiation during follow-up was evaluated through simple and multivariable age/sex stratified logistic regression. Multinomial logistic regression measured the association between predictors and sexual initiation with or without coexisting reproductive risk factors, such as multiple partners or infrequent condom use. Results Baseline sexual experience was reported by 19.2% of 10,757 respondents (median age 15; IQR 14–15; females 59.6%). This was significantly more frequent among pupils older than 15 (41%) and males (20.8%). Of 7,111 pupils without previous experience who were available at follow-up (response rate 81.8%), 17% reported sexual initiation, without differences between females and males. Baseline smoking (age/sex adjusted odds ratio [aOR] 3.63), alcohol use (aOR 2.95), illegal drugs use (aOR 2.72), and poor sleep (aOR 1.71) predicted sexual initiation. Stratified analyses showed a particularly strong association in case of younger and female pupils, and, among girls, when initiation was reported together with multiple partners and/or infrequent condom use. Externalizing (i.e. conduct and hyperactivity) symptoms independently predicted sexual initiation. Internalizing difficulties (i.e. emotional and peer problems) were negatively associated with early and risky sexual

  9. Correlates of sexual initiation among European adolescents.

    Directory of Open Access Journals (Sweden)

    Pietro Gambadauro

    Full Text Available Sexuality is a physiological component of adolescent development, though early initiation is associated with reproductive health risk. This study aimed at identifying correlates and predictors of sexual initiation in a large multinational cohort of European adolescents.A questionnaire addressing socio-demographics, behaviours, mental health and sexual activity, was delivered to 11,110 adolescents recruited from 168 randomly selected schools in 10 European countries between 2009 and 2011. A follow-up questionnaire was delivered after 12 months. The longitudinal association of baseline risk behaviors, psychological attributes and contextual vulnerabilities, with sexual initiation during follow-up was evaluated through simple and multivariable age/sex stratified logistic regression. Multinomial logistic regression measured the association between predictors and sexual initiation with or without coexisting reproductive risk factors, such as multiple partners or infrequent condom use.Baseline sexual experience was reported by 19.2% of 10,757 respondents (median age 15; IQR 14-15; females 59.6%. This was significantly more frequent among pupils older than 15 (41% and males (20.8%. Of 7,111 pupils without previous experience who were available at follow-up (response rate 81.8%, 17% reported sexual initiation, without differences between females and males. Baseline smoking (age/sex adjusted odds ratio [aOR] 3.63, alcohol use (aOR 2.95, illegal drugs use (aOR 2.72, and poor sleep (aOR 1.71 predicted sexual initiation. Stratified analyses showed a particularly strong association in case of younger and female pupils, and, among girls, when initiation was reported together with multiple partners and/or infrequent condom use. Externalizing (i.e. conduct and hyperactivity symptoms independently predicted sexual initiation. Internalizing difficulties (i.e. emotional and peer problems were negatively associated with early and risky sexual initiation among boys

  10. Indian concepts on sexuality.

    Science.gov (United States)

    Chakraborty, Kaustav; Thakurata, Rajarshi Guha

    2013-01-01

    India is a vast country depicting wide social, cultural and sexual variations. Indian concept of sexuality has evolved over time and has been immensely influenced by various rulers and religions. Indian sexuality is manifested in our attire, behavior, recreation, literature, sculptures, scriptures, religion and sports. It has influenced the way we perceive our health, disease and device remedies for the same. In modern era, with rapid globalization the unique Indian sexuality is getting diffused. The time has come to rediscover ourselves in terms of sexuality to attain individual freedom and to reinvest our energy to social issues related to sexuality.

  11. Sexuality and Chronic Kidney Disease

    Science.gov (United States)

    ... Events Advocacy Donate A to Z Health Guide Sexuality and Kidney Disease Tweet Share Print Email Can ... It's something everyone needs. Many people think that sexuality refers only to sexual intercourse. But sexuality includes ...

  12. Correlation between investment in sexual traits and valve sexual dimorphism in Cyprideis species (Ostracoda.

    Directory of Open Access Journals (Sweden)

    Maria João Fernandes Martins

    Full Text Available Assessing the long-term macroevolutionary consequences of sexual selection has been hampered by the difficulty of studying this process in the fossil record. Cytheroid ostracodes offer an excellent system to explore sexual selection in the fossil record because their readily fossilized carapaces are sexually dimorphic. Specifically, males are relatively more elongate than females in this superfamily. This sexual shape difference is thought to arise so that males carapaces can accommodate their very large copulatory apparatus, which can account for up to one-third of body volume. Here we test this widely held explanation for sexual dimorphism in cytheroid ostracodes by correlating investment in male genitalia, a trait in which sexual selection is seen as the main evolutionary driver, with sexual dimorphism of carapace in the genus Cyprideis. We analyzed specimens collected in the field (C. salebrosa, USA; C. torosa, UK and from collections of the National Museum of Natural History, Washington, DC (C. mexicana. We digitized valve outlines in lateral view to obtain measures of size (valve area and shape (elongation, measured as length to height ratio, and obtained several dimensions from two components of the hemipenis: the muscular basal capsule, which functions as a sperm pump, and the section that includes the intromittent organ (terminal extension. In addition to the assessment of this primary sexual trait, we also quantified two dimensions of the male secondary sexual trait-where the transformed right walking leg functions as a clasping organ during mating. We also measured linear dimensions from four limbs as indicators of overall (soft-part body size, and assessed allometry of the soft anatomy. We observed significant correlations in males between valve size, but not elongation, and distinct structural parts of the hemipenis, even after accounting for their shared correlation with overall body size. We also found weak but significant

  13. Sexuality, aging, and dementia.

    Science.gov (United States)

    Benbow, Susan Mary; Beeston, Derek

    2012-07-01

    Sexuality in later life and its relationship to dementia is a neglected topic: greater understanding of the area has the potential to contribute to the quality of life of people with dementia, their family members, and formal carers. We review current knowledge about sexuality, aging, and dementia. We undertook a review of the recent literature to examine of the following areas: what is known about sexuality and aging, and about attitudes to sexuality and aging; what is known about the relevance of sexuality and aging to people living with dementia and their care; and the management of sexual behaviors causing concern to others. Sexual activity decreases in frequency with increasing age but many older people remain sexually active; there is no age limit to sexual responsiveness; and sexuality is becoming more important to successive cohorts of older people, including people living with dementia and gay, lesbian, bisexual, and transgendered elderly people. Attitudes and beliefs toward sexuality and aging are strongly influenced by stereotypes and myths, not only among the general public but also among those working in health and social care. Professional bodies should include sexuality, aging, and dementia in their training curricula. More work is needed on the impact of environmental issues, particularly in group living situations, on older adults' sexuality, and on consent issues. Ethical decision-making frameworks can be useful in practice. Organizations should investigate how to support staff in avoiding a problem-orientated approach and focus on providing holistic person-centered care.

  14. “Sexting” and its relation to sexual activity and sexual risk behavior in a national survey of adolescents

    Science.gov (United States)

    Ybarra, Michele L.; Mitchell, Kimberly J.

    2014-01-01

    Objective To examine the relation between “sexting,” (sending and sharing sexual photos online via text messaging and in-person) with sexual risk behaviors and psychosocial challenge in adolescence. Methods Data were collected online between 2010 and 2011 with 3,715 randomly selected 13- to 18-year-old youth across the United States. Results Seven percent of youth reported sending or showing someone sexual pictures of themselves, where they were nude or nearly nude, online, via text messaging, or in-person, during the past year. Although females and older youth were more likely to share sexual photos than males and younger youth, the profile of psychosocial challenge and sexual behavior was similar for all youth. After adjusting for demographic characteristics, sharing sexual photos was associated with all types of sexual behaviors assessed (e.g., oral sex, vaginal sex) as well as some of the risky sexual behaviors examined—particularly having concurrent sexual partners and having more past-year sexual partners. Adolescents who shared sexual photos also were more likely to use substances and less likely to have high self-esteem than their demographically similar peers. Conclusions While the media has portrayed “sexting” as a problem caused by new technology, health professionals may be more effective by approaching it as an aspect of adolescent sexual development and exploration and, in some cases, risk-taking and psychosocial challenge. PMID:25266148

  15. "Sexting" and its relation to sexual activity and sexual risk behavior in a national survey of adolescents.

    Science.gov (United States)

    Ybarra, Michele L; Mitchell, Kimberly J

    2014-12-01

    To examine the relation between "sexting" (sending and sharing sexual photos online, via text messaging, and in person) with sexual risk behaviors and psychosocial challenge in adolescence. Data were collected online between 2010 and 2011 with 3,715 randomly selected 13- to 18-year-old youth across the United States. Seven percent of youth reported sending or showing someone sexual pictures of themselves, in which they were nude or nearly nude, online, via text messaging, or in person, during the past year. Although females and older youth were more likely to share sexual photos than males and younger youth, the profile of psychosocial challenge and sexual behavior was similar for all youth. After adjusting for demographic characteristics, sharing sexual photos was associated with all types of sexual behaviors assessed (e.g., oral sex, vaginal sex) as well as some of the risky sexual behaviors examined-particularly having concurrent sexual partners and having more past-year sexual partners. Adolescents who shared sexual photos also were more likely to use substances and less likely to have high self-esteem than their demographically similar peers. Although the media has portrayed sexting as a problem caused by new technology, health professionals may be more effective by approaching it as an aspect of adolescent sexual development and exploration and, in some cases, risk-taking and psychosocial challenge. Copyright © 2014 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  16. Effect of curing time on selected properties of soil stabilized with fly ash, marble dust and waste sand for road sub-base materials.

    Science.gov (United States)

    Firat, Seyhan; Khatib, Jamal M; Yilmaz, Gulgun; Comert, A T

    2017-07-01

    The properties of sub-base filling materials in highway construction are essential, as they can determine the performance of the road in service. Normally, the existing materials are removed and replaced with new materials that have adequate load-bearing capacity. Rising environmental concern and new environmental legislations have made construction professionals consider other methods. These methods include stabilizing the existing materials with other additives to improve their performance. Additives can be waste materials generated by different industries. In this work, the existing excavated soil is stabilized with waste materials. The wastes consisted of fly ash, marble dust and waste sand. The percentage addition of waste materials was 5%, 10%, 15% and 20% (by mass) of the existing soil. The soil/waste specimens were cured for 1, 7, 28, 56, 90 and 112 days before testing. Testing included the dry unit weight and unconfined compressive strength ( q u ) as well as X-ray diffraction analysis and scanning electron microscopy observation. Also, the California Bearing Ratio values were obtained and are reported in this investigation. The results showed that the q u values increased with the increase in waste materials content. Also, there is tendency for the dry unit weight to increase with the increase in waste materials.

  17. The Relevance of Political Stability on FDI: A VAR Analysis and ARDL Models for Selected Small, Developed, and Instability Threatened Economies

    Directory of Open Access Journals (Sweden)

    Petar Kurecic

    2017-06-01

    Full Text Available This paper studies the relevance of political stability on foreign direct investment (FDI and the relevance of FDI on economic growth, in three panels. The first panel contains 11 very small economies; the second contains five well-developed and politically stable economies with highly positive FDI net inflows, while the third is a panel with economies that are prone to political violence or targeted by the terrorist attacks. We employ a Granger causality test and implement a vector autoregressive (VAR framework within the panel setting. In order to test the sensitivity of the results and avoid robust errors, we employ an ARDL model for each of the countries within every panel. Based upon our results, we conclude that there is a long-term relationship between political stability and FDI for the panel of small economies, while we find no empiric evidence of such a relationship for both panels of larger and more developed economies. Similarly to the original hypothesis of Lucas (1990, we find that FDI outflows tend to go towards politically less stable countries. On the other hand, the empiric methodology employed did not find such conclusive evidence in the panels of politically more developed countries or in the small economies that this paper observes.

  18. Sexual Distress and Sexual Problems During Pregnancy: Associations With Sexual and Relationship Satisfaction.

    Science.gov (United States)

    Vannier, Sarah A; Rosen, Natalie O

    2017-03-01

    Sexual problems are common during pregnancy, but the proportion of pregnant women who experience sexual distress is unknown. In non-pregnant samples, sexual distress is associated with lower sexual and relationship satisfaction. To identify the proportion of women experiencing sexual distress during pregnancy and to compare the sexual and relationship satisfaction of women who report sexual distress during pregnancy with that of women without distress. Two-hundred sixty-one pregnant women completed a cross-sectional online survey. Women completed validated measurements of sexual functioning (Female Sexual Function Index; score sexual problem), sexual distress (Female Sexual Distress Scale; score ≥ 15 indicates clinically significant distress), sexual satisfaction (Global Measure of Sexual Satisfaction), and relationship satisfaction (Couples Satisfaction Index). Overall, 42% of women met the clinical cutoff for sexual distress. Of sexually active women (n = 230), 26% reported concurrent sexual problems and distress and 14% reported sexual distress in the absence of sexual problems. Sexual distress and/or problems in sexual functioning were linked to lower sexual and relationship satisfaction compared with pregnant women with lower sexual distress and fewer sexual problems. Sexual distress is common during pregnancy and associated with lower sexual and relationship satisfaction. Health care providers should ask pregnant women about feelings of sexual distress. Identifying pregnant women who experience sexual distress and referring them to appropriate resources could help minimize sexual and relationship problems during pregnancy. Vannier SA, Rosen NO. Sexual Distress and Sexual Problems During Pregnancy: Associations With Sexual and Relationship Satisfaction. J Sex Med 2017;14:387-395. Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

  19. Your Sexual Health

    Science.gov (United States)

    ... increase arousal? • What can help me have an orgasm? • How can I minimize sexual pain? • How can ... difficulties. What are orgasmic problems? Not having an orgasm during sexual activity may not be a problem. ...

  20. Sexual Health and Menopause

    Science.gov (United States)

    ... pass through menopause and discover its effects on sexuality. And that’s something we can all be grateful for, since our understanding of how menopause and aging affect sexual health has grown a lot in ...

  1. Aging and sexuality.

    Science.gov (United States)

    Yee, Lesley

    2010-10-01

    Sexuality has become a medical issue in association with aging. This is due to a number of factors, including increasing age of survival, a positive societal construct that promotes sexuality as important for quality of life as we age, and the medicalisation of sexuality with the advent of prescription medications to treat sexual dysfunction. This article reviews the factors surrounding aging and sexuality and also considers special situations with age, such as institutionalised care and the possibility of elder abuse. Normal physiological changes with aging affect both genders in terms of sexual desire and performance. Other medical conditions increase with age, and these and their treatments will impact on sexuality and the way it can be expressed. Medical practitioners require an understanding of these changes in order to find ways to optimise sexual function in older patients.

  2. Adolescent sexual victimization

    DEFF Research Database (Denmark)

    Bramsen, Rikke Holm; Lasgaard, Mathias; Koss, Mary P

    2012-01-01

    at baseline and first time APSV during a 6-month period. Data analysis was a binary logistic regression analysis. Number of sexual partners and displaying sexual risk behaviors significantly predicted subsequent first time peer-on-peer sexual victimization, whereas a history of child sexual abuse, early......The present study set out to investigate predictors of first time adolescent peer-on-peer sexual victimization (APSV) among 238 female Grade 9 students from 30 schools in Denmark. A prospective research design was utilized to examine the relationship among five potential predictors as measured...... sexual onset and failing to signal sexual boundaries did not. The present study identifies specific risk factors for first time sexual victimization that are potentially changeable. Thus, the results may inform prevention initiatives targeting initial experiences of APSV....

  3. Scleroderma and Sexuality

    Science.gov (United States)

    Scleroderma and Sexuality INTRODUCTION If you or your partner have been diagnosed with scleroderma, you may be wondering how this will ... will continue to find satisfaction and enjoyment through sexuality. If you are single, you may wonder how ...

  4. Rape and Sexual Assault

    Science.gov (United States)

    ... PDF 73K) | Appendix H: Data Tables for Sexual Harassment and Sexual Assault Perpetration (PDF 79K) | Appendix I: Data Tables for School Connectedness and Campus Climate (PDF 140K) | Appendix J: ...

  5. Number of sexual partners and sexual assertiveness predict sexual victimization: do more partners equal more risk?

    Science.gov (United States)

    Walker, Dave P; Messman-Moore, Terri L; Ward, Rose Marie

    2011-01-01

    In previous studies, number of sexual partners and sexual assertiveness were examined as independent risk factors for sexual victimization among college women. Using a sample of 335 college women, this study examined the interaction of number of sexual partners and sexual assertiveness on verbal sexual coercion and rape. Approximately 32% of the sample reported unwanted sexual intercourse, 6.9% (n = 23) experienced verbal sexual coercion, 17.9% (n = 60) experienced rape, and 7.2% (n = 24) experienced both. As number of sexual partners increased, instances of verbal sexual coercion increased for women low in relational sexual assertiveness but not for women high in relational sexual assertiveness. A similar relationship was not found for rape. Among women who experienced both verbal sexual coercion and rape, increases in number of partners in the context of low refusal and relational assertiveness were associated with increases in verbal sexual coercion and rape. Findings suggest sexual assertiveness is related to fewer experiences of sexual coercion.

  6. An Overview of Sexual Harassment

    Science.gov (United States)

    Stier, William F., Jr.

    2005-01-01

    Sexual harassment, according to the Equal Employment Opportunity Commission (EEOC), is when any unwelcome sexual advances for sexual favors, and other verbal or physical conduct of a sexual nature takes place. For sexual harassment to take place there must be some type of behavior, language, or material of a sexual nature, which is offensive.…

  7. Sexual Desire Disorders

    OpenAIRE

    Montgomery, Keith A.

    2008-01-01

    Hypoactive sexual desire disorder (HSDD) and sexual aversion disorder (SAD) are an under-diagnosed group of disorders that affect men and women. Despite their prevalence, these two disorders are often not addressed by healthcare providers and patients due their private and awkward nature. As physicians, we need to move beyond our own unease in order to adequately address our patients’ sexual problems and implement appropriate treatment. Using the Sexual Response Cycle as the model of the phys...

  8. Sexual Arousal and Sexually Explicit Media (SEM)

    DEFF Research Database (Denmark)

    Hald, Gert Martin; Stulhofer, Aleksandar; Lange, Theis

    2018-01-01

    -mainstream and mainstream SEM groups, and (iii) to explore the validity and predictive accuracy of the Non-Mainstream Pornography Arousal Scale (NPAS). METHODS: Online cross-sectional survey of 2,035 regular SEM users in Croatia. MAIN OUTCOMES MEASURES: Patterns of sexual arousal to 27 different SEM themes, sexual...

  9. Components of Sexual Identity

    Science.gov (United States)

    Shively, Michael G.; DeCecco, John P.

    1977-01-01

    This paper examines the four components of sexual identity: biological sex, gender identity, social sex-role, and sexual orientation. Theories about the development of each component and how they combine and conflict to form the individual's sexual identity are discussed. (Author)

  10. Sexual Harassment in Education.

    Science.gov (United States)

    Lewis, John F.; And Others

    As in many other areas of society, sexual harassment has become an important issue in education. It has left the educational community with many questions about what constitutes sexual harassment, how to prevent it, and how to deal with the legal problems that may arise concerning it. This report dispels several myths about sexual harassment in…

  11. Loneliness and Sexual Dysfunctions.

    Science.gov (United States)

    Mijuskovic, Ben

    1987-01-01

    Argues that sexual dysfunctions result from early childhood experiences which were originally nonsexual in nature. Contends that psychological difficulties centered around problems of loneliness tend to generate certain sexual dysfunctions. Extends and explores suggestion that genesis of sexual conflicts is in nonsexual infant separation anxiety…

  12. Rethinking Sexual Citizenship

    Science.gov (United States)

    Richardson, Diane

    2016-01-01

    Over the last two decades sexuality has emerged as a key theme in debates about citizenship, leading to the development of the concept of sexual citizenship. This article reviews this literature and identifies four main areas of critical framing: work that contests the significance of sexuality to citizenship; critiques that focus on the possibilities and limitations of mobilising the language of citizenship in sexual politics; analyses of sexual citizenship in relation to nationalisms and border making; and literature that critically examines western constructions of sexuality and sexual politics underpinning understandings of sexual citizenship. In order to progress the field theoretically, the article seeks to extend critiques of sexual citizenship focusing on two key aspects of its construction: the sexual citizen-subject and spaces of sexual citizenship. It argues for a critical rethink that encompasses a de-centring of a ‘western-centric’ focus in order to advance understandings of how sexual citizenship operates both in the Global North and South. PMID:28490816

  13. Toddlers and Sexual Behavior

    Science.gov (United States)

    ... that seems sexual to an adult is not sexual to children. They think about it as play. Sex education should start at home at an early age. References Bushnell P and Lucas L. Questions and Answers About Sex. KidsHealth. ... Sexual Behavior in Children: What's Normal? http://www.mayoclinic. ...

  14. The Influence of Knowledge and Awareness of Sexually Transmitted Diseases (STDs) on Change in Sexual Behaviour of Fresh Undergraduates of the Obafemi Awolowo University, Ile-Ife, Nigeria

    Science.gov (United States)

    Adeniyi, W. O.; Okewole, J. O.

    2014-01-01

    The study examined the influence of knowledge and awareness of sexually transmitted diseases on change in sexual behaviour of fresh undergraduates with a view to providing useful suggestions for positive sexual behaviour of adolescents. The study adopted the descriptive survey design. A sample of 600 fresh undergraduates was selected from the…

  15. Design aspects of the Alpha Repository. VII. Summary of results for the conceptual facility layout, room stability analysis, and equipment selection. Project summary report RSI-0033

    Energy Technology Data Exchange (ETDEWEB)

    Gnirk, P.F.; Grams, W.H.; Zeller, T.J.

    1978-11-03

    In 1975, RE/SPEC Inc. analyzed various design engineering aspects of an Alpha Repository for the disposal and isolation of packages of low-level solid waste and sealed metal canisters of spent fuel cladding waste. The proposed site was located in southeastern New Mexico, with candidate disposal horizons situated in massive bedded salt at depths of 580 to 825 m. The canisters would be emplaced in vertical drillholes in the floors of disposal rooms, and the packages of solid waste subsequently stacked on the floors. Consideration was given to various conceptual facility layouts, the structural stability of the disposal rooms, appropriate excavation/haulage systems, and equipment availability for drilling the canister emplacement holes. This report summarizes the results of the entire study.

  16. Sexuality in older adults: Clinical and psychosocial dilemmas

    OpenAIRE

    Isha Dhingra; Avinash De Sousa; Sushma Sonavane

    2016-01-01

    The present review aims to throw some light on the various aspects of sexuality in older adults and the challenges faced by medical professionals working in this area. Keyword searches using the terms "sexuality," "sexual dysfunction," "geriatric," "old age," and others in combination were carried out on PubMed, Google Scholar, and the Cochrane Database of Systematic Reviews. Relevant clinical trials, case studies, and review papers were selected. This was further supplemented with the clinic...

  17. Visiting Entertainment Venues and Sexual Health in China

    OpenAIRE

    Li, Li; Wu, Zunyou; Rotheram-Borus, Mary Jane; Guan, Jihui; Yin, Yueping; Detels, Roger; Wu, Sheng; Lee, Sung-Jae; Cao, Haijun; Lin, Chunqing; Rou, Keming; Liu, Zhendong

    2008-01-01

    Entertainment venues in China are associated with risky sexual behavior. Most previous studies related to entertainment venues in China have focused on sex workers and commercial sex, but this study addressed sexual health in a sample of the general urban population. A randomly selected sample of market vendors (n = 4,510) from an eastern city was recruited and assessed to examine relationships between entertainment venue visits and sexual risk. Both behavioral (self-reports of unprotected se...

  18. Sexual behavior of single adult American women.

    Science.gov (United States)

    Duberstein Lindberg, Laura; Singh, Susheela

    2008-03-01

    Public policies promoting abstinence until marriage attempt to influence the sexual behavior of the more than 18 million American women who are currently single. An analysis of these women's behavior is needed to inform policies that are responsive to their sexual and reproductive health needs. Sexual behaviors, risk factors and reproductive health needs were examined among a nationally representative sample of 6,493 women aged 20-44 from the 2002 National Survey of Family Growth. Paired t tests were used to assess differences among single, married and cohabiting women by selected demographic, behavioral and risk measures. Thirty-six percent of women aged 20-44 are single, and nine in 10 single women are sexually experienced. Seventy percent of the latter women are currently sexually active; on average, they had intercourse in seven of the last 12 months. A higher proportion of single women (22%) than of cohabiting (9%) or married women (2%) have had two or more partners in the past year, and half of single women are at risk of unintended pregnancy. Furthermore, single women and cohabiting women are more likely to lack health insurance than are married women (21-25% vs. 12%). Because of the high level of sexual activity among single adult women, providers must address their reproductive health care needs and offer appropriate counseling and services. Government policies aimed at encouraging adult women to have sex only within marriage appear out of touch with the reality of the sexual behavior of single women.

  19. Enhancement of Thermal Stability and Selectivity by Introducing Aminotriazine Comonomer to Poly(Octadecyl Acrylate-Grafted Silica as Chromatography Matrix

    Directory of Open Access Journals (Sweden)

    Abul K. Mallik

    2018-02-01

    Full Text Available This paper introduces a poly(octadecyl acrylate (pODA-based organic phase on silica, which is assisted by 2-vinyl-4,6-diamino-1,3,5-triazine (AT, for a chromatography stationary phase. The ODA-AT copolymer grafting onto silica surface was characterized by elemental analysis, FT-IR spectroscopy, scanning electron microscopy, thermo gravimetric analysis and differential scanning calorimeter (DSC. An endothermic peak top of the copolymer-grafted silica was increased to 46 °C from 38 °C, which was a peak top of pODA homopolymer. For high performance liquid chromatography (HPLC application, the molecular selectivity increased with an increase in the AT contents of the ODA-AT copolymer as organic phase. The co-existence of an aminotriazine moiety in the copolymer promoted side-chain ordering of the poly(octadecyl moiety, thus enhancing molecular planarity selectivity for PAHs in reversed-phase liquid chromatography.

  20. Anthropology of sexual exploitation

    Directory of Open Access Journals (Sweden)

    Lalić Velibor

    2009-01-01

    Full Text Available In this paper, the authors observe sexual exploitation from an anthropological perspective. They analyze the rational, ethical, emotional and mythological dimensions of human sexuality. Consequently, after setting the phenomenon in a social and historical context, sexual exploitation is closely observed in the contemporary age. Based on thoughts of relevant thinkers, they make the conclusion that the elimination of sexual exploitation is not an utterly legal issue, but political and economical issues as well. Namely, legal norms are not sufficient to overcome sexual exploitation, but, political and economical relationships in contemporary societies, which will be based on sincere equal opportunities must be established.