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1

Elastic, not plastic species: Frozen plasticity theory and the origin of adaptive evolution in sexually reproducing organisms  

PubMed Central

Background Darwin's evolutionary theory could easily explain the evolution of adaptive traits (organs and behavioral patterns) in asexual but not in sexual organisms. Two models, the selfish gene theory and frozen plasticity theory were suggested to explain evolution of adaptive traits in sexual organisms in past 30 years. Results The frozen plasticity theory suggests that sexual species can evolve new adaptations only when their members are genetically uniform, i.e. only after a portion of the population of the original species had split off, balanced on the edge of extinction for several generations, and then undergone rapid expansion. After a short period of time, estimated on the basis of paleontological data to correspond to 1-2% of the duration of the species, polymorphism accumulates in the gene pool due to frequency-dependent selection; and thus, in each generation, new mutations occur in the presence of different alleles and therefore change their selection coefficients from generation to generation. The species ceases to behave in an evolutionarily plastic manner and becomes evolutionarily elastic on a microevolutionary time-scale and evolutionarily frozen on a macroevolutionary time-scale. It then exists in this state until such changes accumulate in the environment that the species becomes extinct. Conclusion Frozen plasticity theory, which includes the Darwinian model of evolution as a special case - the evolution of species in a plastic state, not only offers plenty of new predictions to be tested, but also provides explanations for a much broader spectrum of known biological phenomena than classic evolutionary theories. Reviewers This article was reviewed by Rob Knight, Fyodor Kondrashov and Massimo Di Giulio (nominated by David H. Ardell). PMID:20067646

2010-01-01

2

The hawk-dove game in a sexually reproducing species explains a colourful polymorphism of an endangered bird.  

PubMed

The hawk-dove game famously introduced strategic game theory thinking into biology and forms the basis of arguments for limited aggression in animal populations. However, aggressive 'hawks' and peaceful 'doves', with strategies inherited in a discrete manner, have never been documented in a real animal population. Thus, the applicability of game-theoretic arguments to real populations might be contested. Here, we show that the head-colour polymorphism of red and black Gouldian finches (Erythrura gouldiae) provides a real-life example. The aggressive red morph is behaviourally dominant and successfully invades black populations, but when red 'hawks' become too common, their fitness is severely compromised (via decreased parental ability). We also investigate the effects of real-life deviations, particularly sexual reproduction, from the simple original game, which assumed asexual reproduction. A protected polymorphism requires mate choice to be sufficiently assortative. Assortative mating is adaptive for individuals because of genetic incompatibilities affecting hybrid offspring fitness, but by allowing red 'hawks' to persist, it also leads to significantly reduced population sizes. Because reductions in male contributions to parental care are generally known to lead to lower population productivity in birds, we expect zero-sum competition to often have wide ranging population consequences. PMID:25209943

Kokko, Hanna; Griffith, Simon C; Pryke, Sarah R

2014-10-22

3

Social and ethical determinants of human sexuality: 1. The need to reproduce.  

PubMed

Aims of this study was to review the many and diverse factors conditioning human sexual behavior; starting with the first and still most important: the need to reproduce and to analyse these factors and how they have changed over time in order to better understand the interplay between the major determinants of human sexuality. For this aim the authors made a literature review of relevant scientific papers and books, including religious websites. At the dawn of humanity, sexuality was focused on reproduction; this, however, did not exclude other important meanings in sexual relationships, since non-conceptive copulations have been a constant aspect of human behavior, becoming an almost unique feature of genus homo. In this respect, the characteristics of a female continuously accessible to her male set the stage for a trend towards monogamy and created the substrate for closed families. Anthropologists have justified conceptive sexuality because sexual activity is costly in terms of energy consumption; for this reason, in the early days, restricting sexual activity made sense for the survival of the species. Traditional ethical considerations and ancient norms by the three major monotheistic religions have favored conceptive sexuality, restricting sexual activity to sanctioned unions and insisting that the major scope of sexuality is procreation. In spite of this, among humans sexuality has always had a wider meaning to the point that for millennia, humans have tried to separate its unitive and procreative meanings. Today much has changed since reproduction can be achieved without intercourse, further separating it from sexual activity. In humans sexuality always possessed multiple meanings, first and foremost reproduction and the creation of a bond between a man and one or several women. PMID:20827251

Benagiano, G; Carrara, S; Filippi, V

2010-08-01

4

Mating type sequences in asexually reproducing Fusarium species  

Microsoft Academic Search

To assess the potential for mating in several Fusarium species with no known sexual stage, we developed degenerate and semidegenerate oligonucleotide primers to identify conserved mating type (MAT) sequences in these fungi. The putative and high-mobility-group (HMG) box sequences from Fusarium avenaceum, F. culmorum, F. poae, and F. semitectum were compared to similar sequences that were described previously for other

Z. Kenényi; Antonio Moretti; Cees Waalwijk; B. Oláh; L. Hornok

2004-01-01

5

MATHEMATICAL BIOSCIENCES 18, 23-54 (1973) 23 Sexually Reproducing Cellular Automata *  

E-print Network

-reproducing cellular automata. It is argued that the transi- tion from asexual to sexual reproduction necessitates to reproduce if it constructs a replica of itself. This process clearly constitutes asexual reproduction reproduction is modeled and investigated in the formal framework of John von Neumann's theory of self

Vitanyi, Paul M.B.

6

Sex in an uncertain world: environmental stochasticity helps restore competitive balance between sexually and asexually reproducing populations.  

PubMed

Like many organisms, individuals of the freshwater ostracod species Eucypris virens exhibit either obligate sexual or asexual reproductive modes. Both types of individual routinely co-occur, including in the same temporary freshwater pond (their natural habitat in which they undergo seasonal diapause). Given the well-known two-fold cost of sex, this begs the question of how sexually reproducing individuals are able to coexist with their asexual counterparts in spite of such overwhelming costs. Environmental stochasticity in the form of 'false dawn' inundations (where the first hydration is ephemeral and causes loss of early hatching individuals) may provide an advantage to the sexual subpopulation, which shows greater variation in hatching times following inundation. We explore the potential role of environmental stochasticity in this system using life-history data analysis, climate data, and matrix projection models. In the absence of environmental stochasticity, the population growth rate is significantly lower in sexual subpopulations. Climate data reveal that 'false dawn' inundations are common. Using matrix projection modelling with and without environmental stochasticity, we demonstrate that this phenomenon can restore appreciable balance to the system, in terms of population growth rates. This provides support for the role of environmental stochasticity in helping to explain the maintenance of sex and the occurrence of geographical parthenogenesis. PMID:24836646

Park, A W; Vandekerkhove, J; Michalakis, Y

2014-08-01

7

Mate-finding as an overlooked critical determinant of dispersal variation in sexually-reproducing animals.  

PubMed

Dispersal is a critically important process in ecology, but robust predictive models of animal dispersal remain elusive. We identify a potentially ubiquitous component of variation in animal dispersal that has been largely overlooked until now: the influence of mate encounters on settlement probability. We use an individual-based model to simulate dispersal in sexually-reproducing organisms that follow a simple set of movement rules based on conspecific encounters, within an environment lacking spatial habitat heterogeneity. We show that dispersal distances vary dramatically with fluctuations in population density in such a model, even in the absence of variation in dispersive traits between individuals. In a simple random-walk model with promiscuous mating, dispersal distributions become increasingly 'fat-tailed' at low population densities due to the increasing scarcity of mates. Similar variation arises in models incorporating territoriality. In a model with polygynous mating, we show that patterns of sex-biased dispersal can even be reversed across a gradient of population density, despite underlying dispersal mechanisms remaining unchanged. We show that some widespread dispersal patterns found in nature (e.g. fat tailed distributions) can arise as a result of demographic variability in the absence of heterogeneity in dispersive traits across the population. This implies that models in which individual dispersal distances are considered to be fixed traits might be unrealistic, as dispersal distances vary widely under a single dispersal mechanism when settlement is influenced by mate encounters. Mechanistic models offer a promising means of advancing our understanding of dispersal in sexually-reproducing organisms. PMID:22662269

Gilroy, James J; Lockwood, Julie L

2012-01-01

8

The number of competitor species is unlinked to sexual dimorphism.  

PubMed

Sexual size dimorphism (SSD) can allow males and females of the same species to specialize on different sized food items and therefore minimize intraspecific competition. Interspecific competition, however, is thought to limit sexual dimorphism, as larger competitors in the community will prevent the larger sex from evolving larger size, and smaller species may prevent the smaller sex from becoming even smaller. We tested this prediction using data on the sexual size dimorphism of lizards, and mammalian carnivores, on islands world-wide. Because insular communities are depauperate, and guilds are species-poor, it is often assumed that enhanced sexual size dimorphism is common on islands. The intensity of interspecific competition, hindering enhanced dimorphism, is thought to increase with competitor richness. We tested whether intraspecific sexual size dimorphism of mammalian carnivores and lizards decreases with increasing island species richness. We further computed the average sexual dimorphism of species on islands and tested whether species-rich islands are inhabited by relatively monomorphic species. Within families and guilds across carnivores and lizards, and with both intraspecific and interspecific approaches, we consistently failed to find support for the notion that species-poor islands harbour more sexually dimorphic individuals or species. We conclude that either interspecific competition does not affect the sexual size dimorphism of insular lizards and carnivores (i.e. character displacement and species sorting are rare in these taxa), or that the number of species in an assemblage or guild is a poor proxy for the intensity of interspecific competition in insular assemblages. PMID:24813336

Meiri, Shai; Kadison, Amy E; Novosolov, Maria; Pafilis, Panayiotis; Foufopoulos, Johannes; Itescu, Yuval; Raia, Pasquale; Pincheira-Donoso, Daniel

2014-05-11

9

Simultaneous Mendelian and clonal genome transmission in a sexually reproducing, all-triploid vertebrate  

PubMed Central

Meiosis in triploids faces the seemingly insuperable difficulty of dividing an odd number of chromosome sets by two. Triploid vertebrates usually circumvent this problem through either asexuality or some forms of hybridogenesis, including meiotic hybridogenesis that involve a reproductive community of different ploidy levels and genome composition. Batura toads (Bufo baturae; 3n = 33 chromosomes), however, present an all-triploid sexual reproduction. This hybrid species has two genome copies carrying a nucleolus-organizing region (NOR+) on chromosome 6, and a third copy without it (NOR?). Males only produce haploid NOR+ sperm, while ova are diploid, containing one NOR+ and one NOR? set. Here, we conduct sibship analyses with co-dominant microsatellite markers so as (i) to confirm the purely clonal and maternal transmission of the NOR? set, and (ii) to demonstrate Mendelian segregation and recombination of the NOR+ sets in both sexes. This new reproductive mode in vertebrates (‘pre-equalizing hybrid meiosis’) offers an ideal opportunity to study the evolution of non-recombining genomes. Elucidating the mechanisms that allow simultaneous transmission of two genomes, one of Mendelian, the other of clonal inheritance, might shed light on the general processes that regulate meiosis in vertebrates. PMID:21993502

Stöck, Matthias; Ustinova, Jana; Betto-Colliard, Caroline; Schartl, Manfred; Moritz, Craig; Perrin, Nicolas

2012-01-01

10

DNA fingerprinting uncovers a new sexually reproducing population of Phytophthora infestans in the Netherlands  

Microsoft Academic Search

The oomycetous fungusPhytophthora infestans (Mont.) de Bary, which causes late blight disease in potatoes, is heterothallic with two known mating types, A1 and A2. From 1845 until 1980 only A1 mating type isolates were found in Europe. In 1980, the A2 mating type appeared permitting sexual reproduction. Here we show that virulence properties and DNA fingerprint patterns of isolates collected

André Drenth; Inge C. Q. Tas; Francine Govers

1994-01-01

11

Sexual reproduction in Aspergillus species of medical or economical importance: Why so fastidious?  

PubMed Central

Heterothallism, which is dependent upon the obligatory cross-mating between self-sterile homokaryotic individuals, represents a common pattern of sexuality in yeasts and molds. Heterothallic reproductive cycles have recently been discovered in three Aspergillus species of medical and economic importance, namely Aspergillus fumigatus, A. parasiticus and A. flavus. Together with Aspergillus udagawae (Neosartorya udagawae), heterothallism has now been discovered in a total of four aspergilli that affect human health or economy. These fungi appear to express relatively low-levels of fertility compared to other heterothallic or homothallic aspergilli and require unusually fastidious environmental parameters to complete the sexual cycle. Since the purpose of sex is to reproduce, we favor the hypothesis that while fertility of these species is on the decline it is compensated by their proficiency to reproduce asexually in wider range of environmental conditions. Heterothallism in these species could provide an invaluable tool for recombinational analysis of factors relevant to pathogenicity or toxin production. There is concern, however, whether extensive recombinational analysis can be very practical in light of the fact that formation of ascospores in these species requires a long period of time and construction of genetically marked strains will likely decrease fertility even further. PMID:19783441

Kwon-Chung, Kyung J.; Sugui, Janyce A.

2009-01-01

12

Species realities and numbers in sexual vertebrates: Perspectives from an asexually transmitted genome  

PubMed Central

A literature review is conducted on the phylogenetic discontinuities in mtDNA sequences of 252 taxonomic species of vertebrates. About 140 of these species (56%) were subdivided clearly into two or more highly distinctive matrilineal phylogroups, the vast majority of which were localized geographically. However, only a small number (two to six) of salient phylogeographic subdivisions (those that stand out against mean within-group divergences) characterized individual species. A previous literature summary showed that vertebrate sister species and other congeners also usually have pronounced phylogenetic distinctions in mtDNA sequence. These observations, taken together, suggest that current taxonomic species often agree reasonably well in number (certainly within an order-of-magnitude) and composition with biotic entities registered in mtDNA genealogies alone. In other words, mtDNA data and traditional taxonomic assignments tend to converge on what therefore may be “real” biotic units in nature. All branches in mtDNA phylogenies are nonanastomose, connected strictly via historical genealogy. Thus, patterns of historical phylogenetic connection may be at least as important as contemporary reproductive relationships per se in accounting for microevolutionary unities and discontinuities in sexually reproducing vertebrates. Findings are discussed in the context of the biological and phylogenetic species concepts. PMID:9927681

Avise, John C.; Walker, DeEtte

1999-01-01

13

Resource competition and patterns of sexual reproduction in sympatric sibling rotifer species  

Microsoft Academic Search

We present experimental data on the reproduction patterns of three sympatric sibling rotifer species, belonging to the Brachionus plicatilis complex, as they compete for food. Variation existed in the amount and pattern of sexual reproduction among the three cyclical parthenogenetic species. Competitive exclusion between the three Brachionus species was related to a higher investment in sexual reproduction by the inferior

Jorge Ciros-Pérez; María José Carmona; Manuel Serra

2002-01-01

14

Mate choice, fecundity and sexual dimorphism in two pipefish species (Syngnathidae)  

Microsoft Academic Search

In order to understand the causes of sexual dimorphism, mate choice and size-related fecundity were studied in two pipefish species, Syngnathus typhle and Nerophis ophidion. Sexual dimorphism is more pronounced in N. ophidion; females are larger, have sexual colourings, and are more active during courtship. In S. typhle the sexes are alike in all these respects. Males brood their offspring

A. Berglund; G. Rosenqvist; I. Svensson

1986-01-01

15

The counterintuitive role of sexual selection in species maintenance and speciation  

PubMed Central

The pronounced and elaborate displays that often differ between closely related animal species have led to the common assumption that sexual selection is important in speciation, especially in geographically separated populations. We use population genetic models to examine the ability of Fisherian sexual selection to contribute to lasting species differentiation by isolating its effect after the onset of gene flow between allopatric populations. We show that when sexually selected traits are under ecologically divergent selection, the situation most favorable to speciation, mating preferences tend to introgress faster than trait alleles, causing sexual selection to counter the effects of local adaptation. As a consequence, the net amount of trait divergence often drops with stronger Fisherian sexual selection. Furthermore, alleles for progressively weaker preferences spread in this context until sexual selection is removed. The effects of pure Fisherian sexual selection on species maintenance are thus much more inhibitory than previously assumed. PMID:24821767

Servedio, Maria R.; Bürger, Reinhard

2014-01-01

16

Sexual species are separated by larger genetic gaps than asexual species in rotifers.  

PubMed

Why organisms diversify into discrete species instead of showing a continuum of genotypic and phenotypic forms is an important yet rarely studied question in speciation biology. Does species discreteness come from adaptation to fill discrete niches or from interspecific gaps generated by reproductive isolation? We investigate the importance of reproductive isolation by comparing genetic discreteness, in terms of intra- and interspecific variation, between facultatively sexual monogonont rotifers and obligately asexual bdelloid rotifers. We calculated the age (phylogenetic distance) and average pairwise genetic distance (raw distance) within and among evolutionarily significant units of diversity in six bdelloid clades and seven monogonont clades sampled for 4211 individuals in total. We find that monogonont species are more discrete than bdelloid species with respect to divergence between species but exhibit similar levels of intraspecific variation (species cohesiveness). This pattern arises because bdelloids have diversified into discrete genetic clusters at a faster net rate than monogononts. Although sampling biases or differences in ecology that are independent of sexuality might also affect these patterns, the results are consistent with the hypothesis that bdelloids diversified at a faster rate into less discrete species because their diversification does not depend on the evolution of reproductive isolation. PMID:24975991

Tang, Cuong Q; Obertegger, Ulrike; Fontaneto, Diego; Barraclough, Timothy G

2014-10-01

17

SEXUAL SPECIES ARE SEPARATED BY LARGER GENETIC GAPS THAN ASEXUAL SPECIES IN ROTIFERS  

PubMed Central

Why organisms diversify into discrete species instead of showing a continuum of genotypic and phenotypic forms is an important yet rarely studied question in speciation biology. Does species discreteness come from adaptation to fill discrete niches or from interspecific gaps generated by reproductive isolation? We investigate the importance of reproductive isolation by comparing genetic discreteness, in terms of intra- and interspecific variation, between facultatively sexual monogonont rotifers and obligately asexual bdelloid rotifers. We calculated the age (phylogenetic distance) and average pairwise genetic distance (raw distance) within and among evolutionarily significant units of diversity in six bdelloid clades and seven monogonont clades sampled for 4211 individuals in total. We find that monogonont species are more discrete than bdelloid species with respect to divergence between species but exhibit similar levels of intraspecific variation (species cohesiveness). This pattern arises because bdelloids have diversified into discrete genetic clusters at a faster net rate than monogononts. Although sampling biases or differences in ecology that are independent of sexuality might also affect these patterns, the results are consistent with the hypothesis that bdelloids diversified at a faster rate into less discrete species because their diversification does not depend on the evolution of reproductive isolation. PMID:24975991

Tang, Cuong Q; Obertegger, Ulrike; Fontaneto, Diego; Barraclough, Timothy G

2014-01-01

18

Biological species is the only possible form of existence for higher organisms: the evolutionary meaning of sexual reproduction  

PubMed Central

Consistent holistic view of sexual species as the highest form of biological existence is presented. The Weismann's idea that sex and recombination provide the variation for the natural selection to act upon is dominated in most discussions of the biological meaning of the sexual reproduction. Here, the idea is substantiated that the main advantage of sex is the opposite: the ability to counteract not only extinction but further evolution as well. Living systems live long owing to their ability to reproduce themselves with a high fidelity. Simple organisms (like bacteria) reach the continued existence due to the high fidelity of individual genome replication. In organisms with a large genome and complex development, the achievable fidelity of DNA replication is not enough for the precise reproduction of the genome. Such species must be capable of surviving and must remain unchanged in spite of the continuous changes of their genes. This problem has no solution in the frame of asexual ("homeogenomic") lineages. They would rapidly degrade and become extinct or blurred out in the course of the reckless evolution. The core outcome of the transition to sexual reproduction was the creation of multiorganismic entity - biological species. Individual organisms forfeited their ability to reproduce autonomously. It implies that individual organisms forfeited their ability to substantive evolution. They evolve as a part of the biological species. In case of obligatory sexuality, there is no such a thing as synchronic multi-level selection. Natural selection cannot select anything that is not a unit of reproduction. Hierarchy in biology implies the functional predestination of the parts for the sake of the whole. A crucial feature of the sexual reproduction is the formation of genomes of individual organisms by random picking them over from the continuously shuffled gene pool instead of the direct replication of the ancestor's genome. A clear anti-evolutionary consequence of the sexuality is evident from the fact that the genotypes of the individuals with an enhanced competitiveness are not transmitted to the next generation. Instead, after mating with "ordinary" individuals, these genotypes scatter and rearrange in new gene combinations, thus preventing the winner from exploiting the success. Reviewers This article was reviewed by Pierre Antoine Pontarotti, Michael T. Ghiselin (nominated by Dr. Juergen Brosius) and Emanuel Tannenboum (nominated by Dr. Doron Lancet) PMID:20307287

2010-01-01

19

Uncoupling of sexual reproduction from homologous recombination in homozygous Oenothera species  

PubMed Central

Salient features of the first meiotic division are independent segregation of chromosomes and homologous recombination (HR). In non-sexually reproducing, homozygous species studied to date HR is absent. In this study, we constructed the first linkage maps of homozygous, bivalent-forming Oenothera species and provide evidence that HR was exclusively confined to the chromosome ends of all linkage groups in our population. Co-segregation of complementary DNA-based markers with the major group of AFLP markers indicates that HR has only a minor role in generating genetic diversity of this taxon despite its efficient adaptation capability. Uneven chromosome condensation during meiosis in Oenothera may account for restriction of HR. The use of plants with ancient chromosomal arm arrangement demonstrates that limitation of HR occurred before and independent from species hybridizations and reciprocal translocations of chromosome arms—a phenomenon, which is widespread in the genus. We propose that consecutive loss of HR favored the evolution of reciprocal translocations, beneficial superlinkage groups and ultimately permanent translocation heterozygosity. PMID:21448231

Rauwolf, U; Greiner, S; Mrá?ek, J; Rauwolf, M; Golczyk, H; Mohler, V; Herrmann, R G; Meurer, J

2011-01-01

20

PARASITES AND SEXUAL REPRODUCTION IN PSYCHID MOTHS  

Microsoft Academic Search

Persistence of sexual reproduction among coexisting asexual competitors has been a major paradox in evolutionary biology. The number of empirical studies is still very limited, as few systems with coexisting sexual and strictly asexual lineages have been found. We studied the ecological mechanisms behind the simultaneous coexistence of a sexually and an asexually reproducing closely related species of psychid moth

Tomi Kumpulainen; Alessandro Grapputo; Johanna Mappes

2004-01-01

21

Decrease of sexual organ reciprocity between heterostylous primrose species, with possible functional and evolutionary implications  

PubMed Central

Background and Aims Heterostyly is a floral polymorphism that has fascinated evolutionary biologists since Darwin's seminal studies on primroses. The main morphological characteristic of heterostyly is the reciprocal placement of anthers and stigmas in two distinct (distyly) floral morphs. Variation in the degree of intermorph sexual reciprocity is relatively common and known to affect patterns of pollen transfer within species. However, the partitioning of sexual organ reciprocity within and between closely related species remains unknown. This study aimed at testing whether intermorph sexual reciprocity differs within vs. between primrose species that hybridize in nature and whether the positions of sexual organs are correlated with other floral traits. Methods Six floral traits were measured in both floral morphs of 15 allopatric populations of Primula elatior, P. veris and P. vulgaris, and anther–stigma reciprocity was estimated within and between species. A combination of univariate and multivariate approaches was used to test whether positions of reproductive organs were less reciprocal between than within species, to assess correlations between sexual organ positions and other corolla traits, and to quantify differences between morphs and species. Key Results The three species were morphologically well differentiated in most floral traits, except that P. veris and P. vulgaris did not differ significantly in sexual organ positions. Overall, lower interspecific than intraspecific sexual organ reciprocity was detected. This decrease was marked between P. elatior and P. vulgaris, intermediate and variable between P. elatior and P. veris, but negligible between P. veris and P. vulgaris. Conclusions Differences in anther and stigma heights between the analysed primrose species were of the same magnitude or larger than intraspecific differences that altered pollen flow within other heterostylous systems. Therefore, it is possible to suggest that considerable reductions of sexual organ reciprocity between species may lower interspecific pollen flow, with potential effects on reproductive isolation. PMID:23002269

Keller, Barbara; de Vos, Jurriaan M.; Conti, Elena

2012-01-01

22

SEXUALLY DIMORPHIC INFLORESCENCE TRAITS IN A WIND-POLLINATED SPECIES: HERITABILITIES AND GENETIC  

E-print Network

SEXUALLY DIMORPHIC INFLORESCENCE TRAITS IN A WIND- POLLINATED SPECIES: HERITABILITIES AND GENETIC and genetic variation were investigated for inflorescence traits in Schiedea adamantis (Caryophyllaceae to wind pollination. For S. adamantis, dimorphism was pronounced for inflorescence condensation and its

Campbell, Diane

23

Sexual and asexual reproduction of the holothurian Stichopus chloronotus (Echinodermata): a comparison between La Réunion (Indian Ocean) and east Australia (Pacific Ocean)  

Microsoft Academic Search

Stichopus chloronotus (Brandt, 1835) is one among nine aspidochirotide holothurian species known to reproduce both sexually by broadcast spawning and asexually by transverse fission. New data on the sexual cycle of this species in La Réunion are presented here and information available on sexual and asexual reproduction in this species is summarised. Sexual reproduction on La Réunion shows a distinct

CHANTAL CONAND; SVEN UTHICKE; THIERRY HOAREAU

2002-01-01

24

Sexual dimorphism in Australian Echiniscus (Tardigrada, Echiniscidae) with descriptions of three new species  

Microsoft Academic Search

The presence of males in species ofEchiniscushas been reported only as recently as 1987 and is still considered to be rare. However, males have been found to be common in a disproportionately large number of species of this genus found in Australia. Evidence of sexual dimorphism is presented for five species (three of which are new to science), females and

SANDRA K. CLAXTON

1996-01-01

25

Parasite-mediated sexual selection and species divergence in Lake Victoria cichlid fish  

E-print Network

Parasite-mediated sexual selection and species divergence in Lake Victoria cichlid fish MARTINE E selection in the divergence of two species of Lake Victoria cichlids. Pundamilia pundamilia and Pundamilia underlying the diver- gence of a sibling species pair from Lake Victoria. Pundamilia pundamilia

26

Virulence and isozyme diversity of sexual versus asexual collections of Uromyces appendiculatus (bean rust fungus)  

Microsoft Academic Search

Organisms that reproduce sexually have been assumed to be more genetically diverse (have more phenotypes with a more even frequency distribution) than those that are clonal. Rust fungi usually have regular sexual reproduction, but asexual species or populations are not uncommon. Two field collections of the bean rust fungus from sexually reproducing populations were compared with two collections from apparently

James V Groth; John W McCain; Alan P Roelfs

1995-01-01

27

Of mice and rats: key species variations in the sexual differentiation of brain and behavior  

PubMed Central

Mice and rats are important mammalian models in biomedical research. In contrast to other biomedical fields, work on sexual differentiation of brain and behavior has traditionally utilized comparative animal models. As mice are gaining in popularity, it is essential to acknowledge the differences between these two rodents. Here we review neural and behavioral sexual dimorphisms in rats and mice, which highlight species differences and experimental gaps in the literature, that are needed for direct species comparisons. Moving forward, investigators must answer fundamental questions about their chosen organism, and attend to both species and strain differences as they select the optimal animal models for their research questions. PMID:20457175

Bonthuis, P.J.; Cox, K.H.; Searcy, B.T.; Kumar, P.; Tobet, S.; Rissman, E.F.

2010-01-01

28

Sexual dimorphism and interspecific cranial form in two capuchin species: Cebus albifrons and C. apella.  

PubMed

Ontogenetic patterns of sexual dimorphism and cranial form in two capuchin monkeys, Cebus albifrons and C. apella, are investigated by means of univariate, bivariate, and multivariate statistics. The analyses are based on 23 linear variables. Univariate analyses indicate that similar ontogenetic patterns of cranial sexual dimorphism are present; however, interspecific differences exist in timing. Ontogenetic scaling is present in both species' crania; however, it is more prevalent in C. albifrons. Several departures are present in cranial regions associated with orbital shape, the dental arcade, and the muscles of mastication. The latter two indicate that sexual differences in diet and/or foraging strategies may exist. Sexual selection is suggested as being the primary selective regime underlying the observed patterns of cranial sexual dimorphism in each species. Interspecific comparisons confirm that C. apella possesses a more dimorphic cranium than C. albifrons and that sexual dimorphism in C. apella begins earlier in development. Although interspecific ontogenetic scaling is present in some cranial variables, C. apella is not just a scaled-up version of C. albifrons. These sympatric congeners seem to be differentiated by variables related to the orbital region and the masticatory apparatus, as indicated by both departures from ontogenetic scaling and results of the discriminant function analysis. Ecological selection, rather than varying degrees of sexual selection, is likely to be responsible for this finding given that C. apella is known to consume hard-object foods. This is consistent with the predicted outcome of the competitive exclusion principle. PMID:9453698

Masterson, T J

1997-12-01

29

Interspecific sexual isolation and phylogeny among different members of the Drosophila bipectinata species complex.  

PubMed

The degree and pattern of sexual isolation among closely related species can be utilized for predicting the direction of evolution and deriving a phylogeny. The Drosophila bipectinata species complex is a group of four morphologically very similar species, belonging to the ananassae subgroup of the melanogaster species group. Sexual isolation among the members of this complex was studied by employing the male-choice technique. To test the difference between the homogamic and heterogamic matings, chi-square values were calculated under the assumption of random mating and the degree of sexual isolation was measured by estimating isolation index. To test the difference in proportions of heterogamic matings between reciprocal crosses, normal deviate (z) was calculated. The direction of evolution among these species has been discussed in the light of models proposed by different workers. Our results suggest that while D. bipectinata, Drosophila parabipectinata and Drosophila malerkotliana are closely related to each other, D. pseudoananassae is distantly related to these three species. The species pairs D. bipectinata and D. parabipectinata and D. parabipectinata and D. malerkotliana show asymmetrical sexual isolation. Based on this, it is suggested that D. bipectinata and D. malerkotliana share a common ancestor where as D. parabipectinata has been derived from D. bipectinata. Their phylogenetic relationship has been discussed in the light of phylogenies suggested by earlier workers. PMID:22638827

Banerjee, Parul; Singh, Bashisth N

2012-03-01

30

Sexual systems in scleractinian corals: an unusual pattern in the reef-building species Diploastrea heliopora  

NASA Astrophysics Data System (ADS)

The sexual system in corals refers to the spatial and temporal pattern of sexual function within an individual coral polyp, colony or population. Although information on sexual systems now exists for over 400 scleractinian species, data are still lacking for some important reef-building taxa. The vast majority of scleractinians are either simultaneous hermaphrodites or gonochoric with other sexual systems rarely occurring. Diploastrea heliopora is one of the most ubiquitous and easily recognised reef-building species in the Indo-West Pacific; however, surprisingly little is known about its reproductive biology. The aim of the present study was to examine the reproductive biology of D. heliopora colonies on chronically impacted, equatorial reefs south of Singapore. Here we show that in Singapore, D. heliopora is a broadcast spawner with predominantly gonochoric polyps. Colonies, however, contained male, female and a low proportion of cosexual polyps during the 14-month sampling period. The most plausible explanation for this is that polyps switch sexes with oogenic and spermatogenic cycles occasionally overlapping. This leads to colony level alternation of sex function within and between breeding seasons. While this sexual system is atypical for scleractinians, it supports molecular evidence that D. heliopora is phylogenetically distinct from species formerly in the family Faviidae.

Guest, J. R.; Baird, A. H.; Goh, B. P. L.; Chou, L. M.

2012-09-01

31

Sexual harassment in live-bearing fishes (Poeciliidae): comparing courting and noncourting species  

Microsoft Academic Search

Sexual harassment by males has been reported from several live-bearing fishes (Poeciliidae) and has been shown to inflict costs on females. For example, poeciliid females have reduced feeding opportunities when accompanied by a male because females dedicate attention to avoiding male copulation attempts. Poeciliid species differ considerably in male mating behavior, such as the presence or absence of courtship. Courting

Martin Plath; Amber M. Makowicz; Ingo Schlupp; Michael Tobler

2007-01-01

32

Sexual selection, reproductive behavior, and speciation in the mbuna species flock of Lake Malawi (Pisces: Cichlidae)  

Microsoft Academic Search

The cichlid species flocks of the African Great Lakes represent the most extreme case of adaptive radiation among vertebrates. Recently, attention has focused on the potential for sexual selection to drive or accelerate speciation in these fishes. Cichlids as a whole are social in nature and display complex behavior, particularly during courtship and spawning; however, the extent to which changes

Douglas M. McElroy; Irv Kornfield

1990-01-01

33

The dilemma offemale mate selection in the brown bear, a species with sexually selected infanticide  

Microsoft Academic Search

Because of differential investment in gametes between sexes, females tend to be the more selective sex. Based on this concept, we investigate mate selection in a large carnivore: the brown bear (Ursus arctos). We hypothesize that, in this species with sexually selected infanticide (SSI), females may be faced with a dilemma: either select a high-quality partner based on phenotypic criteria,

Eva Bellemain; Andreas Zedrosser; Stephanie Manel; Lisette P. Waits; Pierre Taberlet; Jon E. Swenson

2006-01-01

34

Species Detection and Identification in Sexual Organisms Using Population Genetic Theory and DNA Sequences  

PubMed Central

Phylogenetic trees of DNA sequences of a group of specimens may include clades of two kinds: those produced by stochastic processes (random genetic drift) within a species, and clades that represent different species. The ratio of the mean pairwise sequence difference between a pair of clades (K) to the mean pairwise sequence difference within a clade (?) can be used to determine whether the clades are samples from different species (K/??4) or the same species (K/?<4) with probability ?0.95. Previously I applied this criterion to delimit species of asexual organisms. Here I use data from the literature to show how it can also be applied to delimit sexual species using four groups of sexual organisms as examples: ravens, spotted leopards, sea butterflies, and liverworts. Mitochondrial or chloroplast genes are used because these segregate earlier during speciation than most nuclear genes and hence detect earlier stages of speciation. In several cases the K/? ratio was greater than 4, confirming the original authors' intuition that the clades were sufficiently different to be assigned to different species. But the K/? ratio split each of two liverwort species into two evolutionary species, and showed that support for the distinction between the common and Chihuahuan raven species is weak. I also discuss some possible sources of error in using the K/? ratio; the most significant one would be cases where males migrate between different populations but females do not, making the use of maternally inherited organelle genes problematic. The K/? ratio must be used with some caution, like all other methods for species delimitation. Nevertheless, it is a simple theory-based quantitative method for using DNA sequences to make rigorous decisions about species delimitation in sexual as well as asexual eukaryotes. PMID:23308113

Birky, C. William

2013-01-01

35

Spatial distribution pattern of a clonal species: effects of differential production of clonal and sexual offspring  

Microsoft Academic Search

The spatial distribution patterns of genets and ramets within populations are expected to change as a function of the frequency\\u000a with which clonal species recruit different types of offspring (sexual and clonal). We used an integrated approach to study\\u000a the spatial arrangement of clonal plants by combining molecular and ecological data using Opuntia microdasys as a study system. The species

Israel G. Carrillo Angeles; Jordan Golubov; Brook G. Milligan; María C. Mandujano

36

Distinguishing between Incomplete Lineage Sorting and Genomic Introgressions: Complete Fixation of Allospecific Mitochondrial DNA in a Sexually Reproducing Fish (Cobitis; Teleostei), despite Clonal Reproduction of Hybrids  

PubMed Central

Distinguishing between hybrid introgression and incomplete lineage sorting causing incongruence among gene trees in that they exhibit topological differences requires application of statistical approaches that are based on biologically relevant models. Such study is especially challenging in hybrid systems, where usual vectors mediating interspecific gene transfers - hybrids with Mendelian heredity - are absent or unknown. Here we study a complex of hybridizing species, which are known to produce clonal hybrids, to discover how one of the species, Cobitis tanaitica, has achieved a pattern of mito-nuclear mosaic genome over the whole geographic range. We appplied three distinct methods, including the method using solely the information on gene tree topologies, and found that the contrasting mito-nuclear signal might not have resulted from the retention of ancestral polymorphism. Instead, we found two signs of hybridization events related to C. tanaitica; one concerning nuclear gene flow and the other suggested mitochondrial capture. Interestingly, clonal inheritance (gynogenesis) of contemporary hybrids prevents genomic introgressions and non-clonal hybrids are either absent or too rare to be detected among European Cobitis. Our analyses therefore suggest that introgressive hybridizations are rather old episodes, mediated by previously existing hybrids whose inheritance was not entirely clonal. Cobitis complex thus supports the view that the type of resulting hybrids depends on a level of genomic divergence between sexual species. PMID:24971792

Choleva, Lukas; Musilova, Zuzana; Kohoutova-Sediva, Alena; Paces, Jan; Rab, Petr; Janko, Karel

2014-01-01

37

Gene expression differences among three Neurospora species reveal genes required for sexual reproduction in Neurospora crassa.  

PubMed

Many fungi form complex three-dimensional fruiting bodies, within which the meiotic machinery for sexual spore production has been considered to be largely conserved over evolutionary time. Indeed, much of what we know about meiosis in plant and animal taxa has been deeply informed by studies of meiosis in Saccharomyces and Neurospora. Nevertheless, the genetic basis of fruiting body development and its regulation in relation to meiosis in fungi is barely known, even within the best studied multicellular fungal model Neurospora crassa. We characterized morphological development and genome-wide transcriptomics in the closely related species Neurospora crassa, Neurospora tetrasperma, and Neurospora discreta, across eight stages of sexual development. Despite diverse life histories within the genus, all three species produce vase-shaped perithecia. Transcriptome sequencing provided gene expression levels of orthologous genes among all three species. Expression of key meiosis genes and sporulation genes corresponded to known phenotypic and developmental differences among these Neurospora species during sexual development. We assembled a list of genes putatively relevant to the recent evolution of fruiting body development by sorting genes whose relative expression across developmental stages increased more in N. crassa relative to the other species. Then, in N. crassa, we characterized the phenotypes of fruiting bodies arising from crosses of homozygous knockout strains of the top genes. Eight N. crassa genes were found to be critical for the successful formation of perithecia. The absence of these genes in these crosses resulted in either no perithecium formation or in arrested development at an early stage. Our results provide insight into the genetic basis of Neurospora sexual reproduction, which is also of great importance with regard to other multicellular ascomycetes, including perithecium-forming pathogens, such as Claviceps purpurea, Ophiostoma ulmi, and Glomerella graminicola. PMID:25329823

Lehr, Nina A; Wang, Zheng; Li, Ning; Hewitt, David A; López-Giráldez, Francesc; Trail, Frances; Townsend, Jeffrey P

2014-01-01

38

Gene Expression Differences among Three Neurospora Species Reveal Genes Required for Sexual Reproduction in Neurospora crassa  

PubMed Central

Many fungi form complex three-dimensional fruiting bodies, within which the meiotic machinery for sexual spore production has been considered to be largely conserved over evolutionary time. Indeed, much of what we know about meiosis in plant and animal taxa has been deeply informed by studies of meiosis in Saccharomyces and Neurospora. Nevertheless, the genetic basis of fruiting body development and its regulation in relation to meiosis in fungi is barely known, even within the best studied multicellular fungal model Neurospora crassa. We characterized morphological development and genome-wide transcriptomics in the closely related species Neurospora crassa, Neurospora tetrasperma, and Neurospora discreta, across eight stages of sexual development. Despite diverse life histories within the genus, all three species produce vase-shaped perithecia. Transcriptome sequencing provided gene expression levels of orthologous genes among all three species. Expression of key meiosis genes and sporulation genes corresponded to known phenotypic and developmental differences among these Neurospora species during sexual development. We assembled a list of genes putatively relevant to the recent evolution of fruiting body development by sorting genes whose relative expression across developmental stages increased more in N. crassa relative to the other species. Then, in N. crassa, we characterized the phenotypes of fruiting bodies arising from crosses of homozygous knockout strains of the top genes. Eight N. crassa genes were found to be critical for the successful formation of perithecia. The absence of these genes in these crosses resulted in either no perithecium formation or in arrested development at an early stage. Our results provide insight into the genetic basis of Neurospora sexual reproduction, which is also of great importance with regard to other multicellular ascomycetes, including perithecium-forming pathogens, such as Claviceps purpurea, Ophiostoma ulmi, and Glomerella graminicola. PMID:25329823

Lehr, Nina A.; Wang, Zheng; Li, Ning; Hewitt, David A.; López-Giráldez, Francesc; Trail, Frances; Townsend, Jeffrey P.

2014-01-01

39

Biological species is the only possible form of existence for higher organisms: the evolutionary meaning of sexual reproduction  

Microsoft Academic Search

: Consistent holistic view of sexual species as the highest form of biological existence is presented. The Weismann's idea that sex and recombination provide the variation for the natural selection to act upon is dominated in most discussions of the biological meaning of the sexual reproduction. Here, the idea is substantiated that the main advantage of sex is the opposite:

Victor P Shcherbakov

2010-01-01

40

Reticulate evolution in the apogamous Dryopteris varia complex (Dryopteridaceae, subg. Erythrovariae, sect. Variae) and its related sexual species in Japan.  

PubMed

Apogamous fern species are often difficult to distinguish from related species because of their continuous morphological variations. To clarify the genetic relationships among the members of the Dryopteris varia complex, we analyzed the nucleotide sequences of the plastid gene rbcL and the nuclear gene PgiC. We also analyzed the diploid sexual species D. caudipinna and D. chinensis, which have not been included in the complex, but were recently shown to be closely related to the complex in a molecular phylogenetic study. The PgiC sequences of the diploid sexual species, D. varia, D. saxifraga, D. sp. 'protobissetiana' (undescribed diploid sexual species), D. caudipinna, and D. chinensis, were well differentiated and hence designated A, B, C, D, and E, respectively. Thus, the PgiC constitution of apogamous species in the complex was as follows: D. bissetiana, B + C; D. kobayashii, B + C + E); D. pacifica, A + C, A + B + C, or A + C + D; D. sacrosancta, A + C + E; and D. saxifragivaria, B + C. These results suggest that these apogamous species are formed by hybridizations of species including not only the three diploid sexual species of the D. varia complex (A, B, and C) but also the two diploid sexual species D. caudipinna (D) and D. chinensis (E), which do not belong to the complex. PMID:25064510

Hori, Kiyotaka; Tono, Akitaka; Fujimoto, Kazuto; Kato, Juntaro; Ebihara, Atsushi; Watano, Yasuyuki; Murakami, Noriaki

2014-11-01

41

A new species of Curius Newman (Coleoptera: Cerambycidae) from Venezuela with notes on sexual dimorphism within the genus  

Microsoft Academic Search

A new species, Curius chemsaki (Coleoptera: Cerambycidae: Cerambycinae: Curiini), from Venezuela is described. Features distinguishing the new species from its congeners as well as a key to the four species are presented. Sexual dimorphism in pronotal and prosternal morphology within the genus is also discussed.

EUGENIO H. NEARNS; ANN M. RAY

2006-01-01

42

Hybrid origin of a swordtail species (Teleostei: Xiphophorus clemenciae) driven by sexual selection.  

PubMed

The swordlike exaggerated caudal fin extensions of male swordtails are conspicuous traits that are selected for through female choice. Swords are one of only few examples where the hypothesis of a pre-existing bias is believed to apply for the evolution of a male trait. Previous laboratory experiments demonstrated that females prefer males with longer swords and even females from some swordless species show an affiliation for males of sworded species. Earlier phylogenetic studies based on maternally inherited mitochondrial DNA placed the sworded southern swordtail Xiphophorus clemenciae with swordless platies, contradicting its morphology-based evolutionary affinities. The analyses of new nuclear DNA markers now recover its traditional phylogenetic placement with other southern swordtails, suggesting that this species was formed by an ancient hybridization event. We propose that sexual selection through female choice was the likely process of hybrid speciation, by mating of platy females with males of an ancestral swordtail lineage. In artificial crosses of descendent species from the two potential ancestral lineages of X. clemenciae the hybrid and backcross males have swords of intermediate lengths. Additionally, mate choice experiments demonstrate that hybrid females prefer sworded males. These experimental lines of evidence make hybridization through xeno-specific sexual selection by female choice the likely mechanism of speciation. PMID:16499697

Meyer, Axel; Salzburger, Walter; Schartl, Manfred

2006-03-01

43

Reproducible Science?  

PubMed Central

The reproducibility of an experimental result is a fundamental assumption in science. Yet, results that are merely confirmatory of previous findings are given low priority and can be difficult to publish. Furthermore, the complex and chaotic nature of biological systems imposes limitations on the replicability of scientific experiments. This essay explores the importance and limits of reproducibility in scientific manuscripts. PMID:20876290

Casadevall, Arturo; Fang, Ferric C.

2010-01-01

44

Sexual imprinting misguides species recognition in a facultative interspecific brood parasite  

PubMed Central

Sexual reproduction relies on the recognition of conspecifics for breeding. Most experiments in birds have implicated a critical role for early social learning in directing subsequent courtship behaviours and mating decisions. This classical view of avian sexual imprinting is challenged, however, by studies of megapodes and obligate brood parasites, species in which reliable recognition is achieved despite the lack of early experience with conspecifics. By rearing males with either conspecific or heterospecific brood mates, we experimentally tested the effect of early social experience on the association preferences and courtship behaviours of two sympatrically breeding ducks. We predicted that redheads (Aythya americana), which are facultative interspecific brood parasites, would show a diminished effect of early social environment on subsequent courtship preferences when compared with their host and congener, the canvasback (Aythya valisineria). Contrary to expectations, cross-fostered males of both species courted heterospecific females and preferred them in spatial association tests, whereas control males courted and associated with conspecific females. These results imply that ontogenetic constraints on species recognition may be a general impediment to the initial evolution of interspecific brood parasitism in birds. Under more natural conditions, a variety of mechanisms may mitigate or counteract the effects of early imprinting for redheads reared in canvasback broods. PMID:20484239

Sorenson, Michael D.; Hauber, Mark E.; Derrickson, Scott R.

2010-01-01

45

Sexual imprinting misguides species recognition in a facultative interspecific brood parasite.  

PubMed

Sexual reproduction relies on the recognition of conspecifics for breeding. Most experiments in birds have implicated a critical role for early social learning in directing subsequent courtship behaviours and mating decisions. This classical view of avian sexual imprinting is challenged, however, by studies of megapodes and obligate brood parasites, species in which reliable recognition is achieved despite the lack of early experience with conspecifics. By rearing males with either conspecific or heterospecific brood mates, we experimentally tested the effect of early social experience on the association preferences and courtship behaviours of two sympatrically breeding ducks. We predicted that redheads (Aythya americana), which are facultative interspecific brood parasites, would show a diminished effect of early social environment on subsequent courtship preferences when compared with their host and congener, the canvasback (Aythya valisineria). Contrary to expectations, cross-fostered males of both species courted heterospecific females and preferred them in spatial association tests, whereas control males courted and associated with conspecific females. These results imply that ontogenetic constraints on species recognition may be a general impediment to the initial evolution of interspecific brood parasitism in birds. Under more natural conditions, a variety of mechanisms may mitigate or counteract the effects of early imprinting for redheads reared in canvasback broods. PMID:20484239

Sorenson, Michael D; Hauber, Mark E; Derrickson, Scott R

2010-10-22

46

Reliable and reproducible method for rapid identification of Nocardia species by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.  

PubMed

Recently, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been challenged for the identification of Nocardia species. However, the standard ethanol-formic acid extraction alone is insufficient in allowing the membrane proteins of Nocardia species to be ionized by the matrix. We therefore aimed to establish our new extraction method for the MALDI-TOF MS-based identification of Nocardia species isolates. Our modified extraction procedure is through dissociation in 0.5% Tween-20 followed by bacterial heat-inactivation, mechanical breaking of the cell wall by acid-washed glass beads and protein extraction with formic acid and acetonitrile. As reference methods for species identification, full-length 16S rRNA gene sequencing and some phenotypical tests were used. In a first step, we made our own Nocardia database by analyzing 13 strains (13 different species including N. elegans, N. otitidiscaviarum, N. asiatica, N. abscessus, N. brasiliensis, N. thailandica, N. farcinica, N. nova, N. mikamii, N. cyriacigeorgica, N. asteroids, Nocardiopsis alba, and Micromonospora sp.) and registered to the MALDI BioTyper database. Then we established our database. The analysis of 12 challenge strains using the our database gave a 100% correct identification, including 8 strains identified to the species level and 4 strains to the genus level (N. elegans, N. nova, N. farcinica, Micromonospora sp.) according to the manufacture's log score specifications. In the estimation of reproducibility of our method intended for 4 strains, both within-run and between-run reproducibility were excellent. These data indicates that our method for rapid identification of Nocardia species is with reliability, reproducibility and cost effective. PMID:24800394

Toyokawa, Masahiro; Kimura, Keigo; Nishi, Isao; Sunada, Atsuko; Ueda, Akiko; Sakata, Tomomi; Asari, Seishi

2013-01-01

47

High Interlaboratory Reproducibility of Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry-Based Species Identification of Nonfermenting Bacteria?  

PubMed Central

Matrix-assisted laser desorption ionization-time of flight mass spectrometry has emerged as a rapid, cost-effective alternative for bacterial species identification. Identifying 60 blind-coded nonfermenting bacteria samples, this international study (using eight laboratories) achieved 98.75% interlaboratory reproducibility. Only 6 of the 480 samples were misidentified due to interchanges (4 samples) or contamination (1 sample) or not identified because of insufficient signal intensity (1 sample). PMID:19776231

Mellmann, A.; Bimet, F.; Bizet, C.; Borovskaya, A. D.; Drake, R. R.; Eigner, U.; Fahr, A. M.; He, Y.; Ilina, E. N.; Kostrzewa, M.; Maier, T.; Mancinelli, L.; Moussaoui, W.; Prévost, G.; Putignani, L.; Seachord, C. L.; Tang, Y. W.; Harmsen, D.

2009-01-01

48

Seasonal sexual segregation in two Thalassarche albatross species: competitive exclusion, reproductive role specialization or foraging niche divergence?  

PubMed Central

Sexual segregation by micro- or macrohabitat is common in birds, and usually attributed to size-mediated dominance and exclusion of females by larger males, trophic niche divergence or reproductive role specialization. Our study of black-browed albatrosses, Thalassarche melanophrys, and grey-headed albatrosses, T. chrysostoma, revealed an exceptional degree of sexual segregation during incubation, with largely mutually exclusive core foraging ranges for each sex in both species. Spatial segregation was not apparent during brood-guard or post-guard chick rearing, when adults are constrained to feed close to colonies, providing no evidence for dominance-related competitive exclusion at the macrohabitat level. A comprehensive morphometric comparison indicated considerable species and sexual dimorphism in wing area and wing loading that corresponded, both within and between species, to broad-scale habitat preferences relating to wind strength. We suggest that seasonal sexual segregation in these two species is attributable to niche divergence mediated by differences in flight performance. Such sexual segregation may also have implications for conservation in relation to sex-specific overlap with commercial fisheries. PMID:15306353

Phillips, R. A.; Silk, J. R. D.; Phalan, B.; Catry, P.; Croxall, J. P.

2004-01-01

49

Only Half Right: Species with Female-Biased Sexual Size Dimorphism Consistently Break Rensch's Rule  

PubMed Central

Background Most animal species display Sexual Size Dimorphism (SSD): males and females consistently attain different sizes, most frequently with females being larger than males. However the selective mechanisms driving patterns of SSD remain controversial. ‘Rensch's rule’ proposes a general scaling phenomenon for all taxa, whereby SSD increases with average body size when males are larger than females, and decreases with body size when females are larger than males. Rensch's rule appears to be general in the former case, but there is little evidence for the rule when females are larger then males. Methodology/Principal Findings Using comprehensive data for 1291 species of birds across 30 families, we find strong support for Rensch's rule in families where males are typically larger than females, but no overall support for the rule in families with female-biased SSD. Reviewing previous studies of a broad range of taxa (arthropods, reptiles, fish and birds) showing predominantly female-biased SSD, we conclude that Rensch's conjecture is the exception rather than the rule in such species. Conclusions/Significance The absence of consistent scaling of SSD in taxa with female-biased SSD, the most prevalent direction of dimorphism, calls into question previous general evolutionary explanations for Rensch's rule. We propose that, unlike several other ecological scaling relationships, Rensch's rule does not exist as an independent scaling phenomenon. PMID:17878932

Webb, Thomas J.; Freckleton, Robert P.

2007-01-01

50

[Morphogenesis of the sexual phase of six Mexican species of the Dryopteris (Dryopteridaceae), Part II].  

PubMed

The development of the sexual phase of six Mexican species of Dryopteris is described and compared. Spores of all studied species are monolete, ellipsoid and have a rugose surface; the perine is folded, brown to dark brown, with a tubercled outline. Germination pattern is of the Vittaria-type and the development pattern of the prothallia is of the Aspidium-type. Gametangia are of the common type for the leptosporangiate advanced ferns. First leaves of the sporophytes appear 258-265 after sowing and apparently in Dryopteris pseudo-filix-mas the sporophyte have an apogamic origin (80 days). To make a comparative analysis of gametophytic characteristics in the twelve Mexican species and conclude of germination is of the Vittaria-type and development pattern prothallial is of the Aspidium-type, and unicelular trichomes on margin and superficial gametophytic to yield irregular aspect are characteristics to yield unit and characteristic to genera to conform Dryopteridaceae family (sensu Moran 1995) with the exception of Didymochlaena genus. PMID:11795155

Pérez-García, B; Mendoza, A; Reyes Jaramillo, I; Riba, R

2001-03-01

51

Dissecting the Causes of Variation in Intra-Floresence Allocation in a Sexually Polymorphic Species, Fragaria virginiana (Rosaceae)  

Microsoft Academic Search

In this study we dissect the causes of variation in intra-inflorescence allocation in a sexually polymorphic species, Fragaria virginiana. We separated out the effects of resource competition during flowering from those of inflorescence architecture, as well as identified the effects of sex morph and genotype. We found position-based variation in petal length, ovule, pollen, and flower number to be influenced

Tia-Lynn Ashman; Michael S. Hitchens

2000-01-01

52

Multigene Assessment of the Species Boundaries and Sexual Status of the Basidiomycetous Yeasts Cryptococcus flavescens and C. terrestris (Tremellales)  

PubMed Central

Cryptococcus flavescens and C. terrestris are phenotypically indistinguishable sister species that belong to the order Tremellales (Tremellomycetes, Basidiomycota) and which may be mistaken for C. laurentii based on phenotype. Phylogenetic separation between C. flavescens and C. terrestris was based on rDNA sequence analyses, but very little is known on their intraspecific genetic variability or propensity for sexual reproduction. We studied 59 strains from different substrates and geographic locations, and used a multilocus sequencing (MLS) approach complemented with the sequencing of mating type (MAT) genes to assess genetic variation and reexamine the boundaries of the two species, as well as their sexual status. The following five loci were chosen for MLS: the rDNA ITS-LSU region, the rDNA IGS1 spacer, and fragments of the genes encoding the largest subunit of RNA polymerase II (RPB1), the translation elongation factor 1 alpha (TEF1) and the p21-activated protein kinase (STE20). Phylogenetic network analyses confirmed the genetic separation of the two species and revealed two additional cryptic species, for which the names Cryptococcus baii and C. ruineniae are proposed. Further analyses of the data revealed a high degree of genetic heterogeneity within C. flavescens as well as evidence for recombination between lineages detected for this species. Strains of C. terrestris displayed higher levels of similarity in all analysed genes and appear to make up a single recombining group. The two MAT genes (STE3 and SXI1/SXI2) sequenced for C. flavescens strains confirmed the potential for sexual reproduction and suggest the presence of a tetrapolar mating system with a biallelic pheromone/receptor locus and a multiallelic HD locus. In C. terrestris we could only sequence STE3, which revealed a biallelic P/R locus. In spite of the strong evidence for sexual recombination in the two species, attempts at mating compatible strains of both species on culture media were unsuccessful. PMID:25811603

Sharma, Lav; Carvalho, Cláudia; Fonseca, Álvaro

2015-01-01

53

Evidence for a sexual dimorphism in gene expression noise in metazoan species.  

PubMed

Many biological processes depend on very few copies of intervening elements, which makes such processes particularly susceptible to the stochastic fluctuations of these elements. The intrinsic stochasticity of certain processes is propagated across biological levels, causing genotype- and environment-independent biological variation which might permit populations to better cope with variable environments. Biological variations of stochastic nature might also allow the accumulation of variations at the genetic level that are hidden from natural selection, which might have a great potential for population diversification. The study of any mechanism that resulted in the modulation of stochastic variation is, therefore, of potentially wide interest. I propose that sex might be an important modulator of the stochastic variation in gene expression, i.e., gene expression noise. Based on known associations between different patterns of gene expression variation, I hypothesize that in metazoans the gene expression noise might be generally larger in heterogametic than in homogametic individuals. I directly tested this hypothesis by comparing putative genotype- and environment-independent variations in gene expression between females and males of Drosophila melanogaster strains. Also, considering the potential effect of the propagation of gene expression noise across biological levels, I indirectly tested the existence of a metazoan sexual dimorphism in gene expression noise by analyzing putative genotype- and environment-independent variation in phenotypes related to interaction with the environment in D. melanogaster strains and metazoan species. The results of these analyses are consistent with the hypothesis that gene expression is generally noisier in heterogametic than in homogametic individuals. Further analyses and discussion of existing literature permits the speculation that the sexual dimorphism in gene expression noise is ultimately based on the nuclear dynamics in gametogenesis and very early embryogenesis of sex-specific chromosomes, i.e., Y and W chromosomes. PMID:25649874

Díaz-Castillo, Carlos

2015-01-01

54

Evidence for a sexual dimorphism in gene expression noise in metazoan species  

PubMed Central

Many biological processes depend on very few copies of intervening elements, which makes such processes particularly susceptible to the stochastic fluctuations of these elements. The intrinsic stochasticity of certain processes is propagated across biological levels, causing genotype- and environment-independent biological variation which might permit populations to better cope with variable environments. Biological variations of stochastic nature might also allow the accumulation of variations at the genetic level that are hidden from natural selection, which might have a great potential for population diversification. The study of any mechanism that resulted in the modulation of stochastic variation is, therefore, of potentially wide interest. I propose that sex might be an important modulator of the stochastic variation in gene expression, i.e., gene expression noise. Based on known associations between different patterns of gene expression variation, I hypothesize that in metazoans the gene expression noise might be generally larger in heterogametic than in homogametic individuals. I directly tested this hypothesis by comparing putative genotype- and environment-independent variations in gene expression between females and males of Drosophila melanogaster strains. Also, considering the potential effect of the propagation of gene expression noise across biological levels, I indirectly tested the existence of a metazoan sexual dimorphism in gene expression noise by analyzing putative genotype- and environment-independent variation in phenotypes related to interaction with the environment in D. melanogaster strains and metazoan species. The results of these analyses are consistent with the hypothesis that gene expression is generally noisier in heterogametic than in homogametic individuals. Further analyses and discussion of existing literature permits the speculation that the sexual dimorphism in gene expression noise is ultimately based on the nuclear dynamics in gametogenesis and very early embryogenesis of sex-specific chromosomes, i.e., Y and W chromosomes. PMID:25649874

2015-01-01

55

Applying the species concept to plant viruses  

Microsoft Academic Search

Summary Plant virologists who maintain that the concept of species cannot be applied to viruses argue their case in terms of an obsolete concept of biological species defined by gene pools and reproductive isolation and applicable only to sexually reproducing organisms. In fact, various species concepts have been used by biologists and some of them are applicable to asexual organisms.

M. H. V. Van Regenmortel

1989-01-01

56

Measurements of atmospheric mercury species during an international study of mercury depletion events at Ny-Ålesund, Svalbard, spring 2003. How reproducible are our present methods?  

NASA Astrophysics Data System (ADS)

Six groups participated in an international study of springtime atmospheric mercury depletion events (AMDEs) at Ny-Ålesund in the Norwegian Arctic during April and May 2003 with the aim to compare analytical methods for measurements of atmospheric mercury species and study the physical and chemical processes leading to AMDEs. Five groups participated in the method comparison that was conducted at three different locations within Ny-Ålesund. Various automated and manual instrumentation were used to sample, measure and compare gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and mercury associated with particles (Hg-P). The concentration of GEM was reproducible during background conditions. For the first time using ambient air, the statistics associated with round robin test procedures were applied. This was found to be an appropriate tool to investigate the reproducibility of GEM measurements in ambient air. The precision for each group measuring GEM concentrations was found to be consistently good (within 5%). Five AMDEs were recorded during the study. Using four different methods, including single and replicate samples, all groups recorded higher values of RGM and Hg-P during AMDEs. The results show that measuring comparable atmospheric mercury species at both the same and different locations (within the Ny-Ålesund area) is difficult. Not only do site location and site characteristics create challenges when trying to intercompare results but there are difficulties, as well, in obtaining comparable results with similar sampling and analysis methods. Nevertheless, with our current procedures for atmospheric mercury identification we can differentiate with certainty between "high" and "low" concentration values of RGM and Hg-P.

Aspmo, Katrine; Gauchard, Pierre-Alexis; Steffen, Alexandra; Temme, Christian; Berg, Torunn; Bahlmann, Enno; Banic, Cathy; Dommergue, Aurelien; Ebinghaus, Ralf; Ferrari, Christophe; Pirrone, Nicola; Sprovieri, Francesca; Wibetoe, Grethe

57

The dilemma of female mate selection in the brown bear, a species with sexually selected infanticide  

PubMed Central

Because of differential investment in gametes between sexes, females tend to be the more selective sex. Based on this concept, we investigate mate selection in a large carnivore: the brown bear (Ursus arctos). We hypothesize that, in this species with sexually selected infanticide (SSI), females may be faced with a dilemma: either select a high-quality partner based on phenotypic criteria, as suggested by theories of mate choice, or rather mate with future potentially infanticidal males as a counter-strategy to SSI. We evaluated which male characteristics were important in paternity assignment. Among males available in the vicinity of the females, the largest, most heterozygous and less inbred and also the geographically closest males were more often the fathers of the female's next litter. We suggest that female brown bears may select the closest males as a counter-strategy to infanticide and exercise a post-copulatory cryptic choice, based on physical attributes, such as a large body size, reflecting male genetic quality. However, male–male competition either in the form of fighting before copulation or during the post-copulatory phase, in the form of sperm competition, cannot entirely be ruled out. PMID:16543170

Bellemain, Eva; Zedrosser, Andreas; Manel, Stéphanie; Waits, Lisette P; Taberlet, Pierre; Swenson, Jon E

2005-01-01

58

Background: Chlamydia trachomatis is the bacterial species causing most sexually transmitted infections. It is of high importance for the public health  

E-print Network

Background: Chlamydia trachomatis is the bacterial species causing most sexually transmitted infections. It is of high importance for the public health since it causes reproductive tract diseases and epidemiology in sexual networks affected by Lymphogranuloma vene- reum, i.e. invasive chlamydia strains causing

Uppsala Universitet

59

Sexual Dimorphism  

E-print Network

and "socially imposed monogamy" showed greater sexual differ- ences in stature than ones following what the authors described as "ecologically imposed" monogamous patterns, which led these authors to postulate that patterns of sexual dimorphism in humans... of Anthropology, University of Michigan, Ann Arbor, Michigan 48109 1Order of the authors is alphabetical. INTRODUCTION That the human species exhibits sexual dimorphism in size, shape, and be- havior is an obvious conclusion from anyone?s simple participation...

Frayer, David W.; Wolpoff, Milford H.

1985-01-01

60

RESEARCH Open Access Elastic, not plastic species: Frozen plasticity  

E-print Network

of adaptive evolution in sexually reproducing organisms Jaroslav Flegr* Abstract Background: Darwin Problems of Current Models of Adaptive Evolution in Sexual Species Darwin's evolutionary theory[1] could's evolutionary theory could easily explain the evolution of adaptive traits (organs and behavioral patterns

Flegr, Jaroslav

61

Ecological selection as the cause and sexual differentiation as the consequence of species divergence?  

PubMed

Key conceptual issues about speciation go unanswered without consideration of non-mutually exclusive factors. With tests based on speciation theory, we exploit the island distribution and habitat differences exhibited by the Caribbean cricket Amphiacusta sanctaecrucis, and with an analysis of divergent ecological selection, sexually selected differentiation and geographical isolation, address how these different factors interact. After testing for divergent selection by comparing neutral genetic and morphological divergence in one ecological (mandible shape) and one sexual (male genitalia shape) trait, we examine whether ecological or sexual selection is the primary mechanism driving population divergence. We find that all three factors--isolation, ecological and sexual selection--contribute to divergence, and that their interaction determines the stage of completeness achieved during the speciation process, as measured by patterns of genetic differentiation. Moreover, despite the striking diversity in genitalic shapes across the genus Amphiacusta, which suggests that sexual selection drives speciation, the significant differences in genitalia shape between forest habitats revealed here implies that ecological divergence may be the primary axis of divergence. Our work highlights critical unstudied aspects in speciation-differentiating the cause from the consequence of divergence-and suggests avenues for further disentangling the roles of natural and sexual selection in driving divergence in Amphiacusta. PMID:23173206

Oneal, Elen; Knowles, L Lacey

2013-01-01

62

Ecological selection as the cause and sexual differentiation as the consequence of species divergence?  

PubMed Central

Key conceptual issues about speciation go unanswered without consideration of non-mutually exclusive factors. With tests based on speciation theory, we exploit the island distribution and habitat differences exhibited by the Caribbean cricket Amphiacusta sanctaecrucis, and with an analysis of divergent ecological selection, sexually selected differentiation and geographical isolation, address how these different factors interact. After testing for divergent selection by comparing neutral genetic and morphological divergence in one ecological (mandible shape) and one sexual (male genitalia shape) trait, we examine whether ecological or sexual selection is the primary mechanism driving population divergence. We find that all three factors—isolation, ecological and sexual selection—contribute to divergence, and that their interaction determines the stage of completeness achieved during the speciation process, as measured by patterns of genetic differentiation. Moreover, despite the striking diversity in genitalic shapes across the genus Amphiacusta, which suggests that sexual selection drives speciation, the significant differences in genitalia shape between forest habitats revealed here implies that ecological divergence may be the primary axis of divergence. Our work highlights critical unstudied aspects in speciation—differentiating the cause from the consequence of divergence—and suggests avenues for further disentangling the roles of natural and sexual selection in driving divergence in Amphiacusta. PMID:23173206

Oneal, Elen; Knowles, L. Lacey

2013-01-01

63

Sexual Selection on Accessory Glands, Genitalia and Protarsal Pads in the Whirligig Beetle Dineutus nigrior Roberts (Coleoptera: Gyrinidae)  

Microsoft Academic Search

Sexual selection is a potent force in the evolution of morphology in sex- ually reproducing species. When large size in a trait is favored by sexual selection the trait often exhibits positive allometry. Mating behavior in whirligig beetles consists of males attempting to grasp reluctant females using enlarged protarsi (protarsal pads). Here we use allometry and a mating experiment to

Evan R. Fairn; Albrecht I. Schulte-Hostedde; Yves Alarie

2007-01-01

64

Species-specific patterns of sexual dimorphism in the expression of fruitless protein, a neural musculinizing factor in Drosophila.  

PubMed

In Drosophila melanogaster, male-specific forms of the fruitless (fru) gene product, mFru protein, function as a neural sex-determination factors that directs the development of at least two male characteristics, namely courtship and mating behavior and the formation of the muscle of Lawrence (MOL). In D. melanogaster, the male-specific expression of Fru protein in motoneurons is responsible for the male-limited induction of the MOL by such neurons. Although no Drosophila species whose females have the MOL are known, there are many Drosophila species whose males lack the MOL. We performed immunohistochemical staining of the central nervous system (CNS) from 9 Drosophila species to determine whether the mFru expression profile is different between MOL-present and MOL-absent species. In 8 of the 9 species, Fru protein expression in the CNS is strictly male-specific, regardless of the presence or absence of the MOL. The sole exception is D. suzukii, in which females express the Fru protein though less extensively than males do: Fru expression in the CNS of female D. suzukii is restricted to the lamina and ventral ganglia. Expression of Fru protein in the lamina is observed in males of D. virilis and in both sexes of D. suzukii, but not in males and females of the 7 other species. These results indicate that sexually dimorphic expression of the Fru protein has been subjected to species-specific modulation during evolution. PMID:16024442

Usui-Aoki, Kazue; Mikawa, Yoshitaka; Yamamoto, Daisuke

2005-01-01

65

Symmetry Is Related to Sexual Dimorphism in Faces: Data Across Culture and Species  

Microsoft Academic Search

BackgroundMany animals both display and assess multiple signals. Two prominently studied traits are symmetry and sexual dimorphism, which, for many animals, are proposed cues to heritable fitness benefits. These traits are associated with other potential benefits, such as fertility. In humans, the face has been extensively studied in terms of attractiveness. Faces have the potential to be advertisements of mate

Anthony C. Little; Benedict C. Jones; Corri Waitt; Bernard P. Tiddeman; David R. Feinberg; David I. Perrett; Coren L. Apicella; Frank W. Marlowe; Thomas Reimchen

2008-01-01

66

Symmetry Is Related to Sexual Dimorphism in Faces: Data Across Culture and Species  

Microsoft Academic Search

Background: Many animals both display and assess multiple signals. Two prominently studied traits are symmetry and sexual dimorphism, which, for many animals, are proposed cues to heritable fitness benefits. These traits are associated with other potential benefits, such as fertility. In humans, the face has been extensively studied in terms of attractiveness. Faces have the potential to be advertisements of

Anthony C. Little; Benedict C. Jones; Corri Waitt; Bernard P. Tiddeman; David R. Feinberg; David I. Perrett; Coren L. Apicella; Frank W. Marlowe

2008-01-01

67

Differential Annual Movement Patterns in a Migratory Species: Effects of Experience and Sexual Maturation  

Microsoft Academic Search

Some animals migrate long distances to exploit important seasonal food resources in the northern regions of the northern hemisphere, whilst avoiding winter starvation. Changes in the individual's age and navigational skills are likely to affect migration, which in turn influences the geographic distribution of individuals. Processes such as sexual maturation and navigational abilities are affected by age, and age is

Paulo E. Jorge; David Sowter; Paulo A. M. Marques

2011-01-01

68

Population genetic structure of diploid sexual and polyploid apomictic hawthorns ( Crataegus ; Rosaceae) in the Pacific Northwest  

Microsoft Academic Search

Polyploidy and gametophytic apomixis are two important and associated processes in plants. Many hawthorn species are polyploids and can reproduce both sexually and apomictically. However, the population genetic structure of these species is poorly understood. Crataegus douglasii is represented exclusively by self-compatible tetraploid pseudogamous apomicts across North America, whereas Crataegus suksdorfii found in the Pacific Northwest is known to include

EUGENIA Y. Y. LO; SAŠA STEFANOVI?; TIMOTHY A. DICKINSON

2009-01-01

69

Dissecting the causes of variation in intra-inflorescence allocation in a sexually polymorphic species, Fragaria virginiana (Rosaceae).  

PubMed

In this study we dissect the causes of variation in intra-inflorescence allocation in a sexually polymorphic species, Fragaria virginiana. We separated out the effects of resource competition during flowering from those of inflorescence architecture, as well as identified the effects of sex morph and genotype. We found position-based variation in petal length, ovule, pollen, and flower number to be influenced more by architecture than by our resource manipulations during flowering. We also found both genotype- and sex-specific intra-inflorescence patterns. Furthermore, our data indicate that the sex morph-specific intra-inflorescence patterns result from architectural modifications of the basic pattern. In fact, sex-differential intra-inflorescence patterns suggest that fitness through male and female function may be maximized by different resource distribution patterns within the inflorescence and may have been modified by past selection. Specifically, females invested heavily in ovules at positions where fruit set was most likely (primary and secondary), at the expense of flower number and allocation per flower at more distal positions. Whereas functional males invested minimally in ovules at all flower positions and produced the most abundantly flowered inflorescences, hermaphrodites, on the other hand, showed intermediate patterns, implying a compromise between sex functions. We suggest that consideration of intra-inflorescence allocation and inflorescence architecture may reveal the mechanism underlying sexual dimorphism in flower allocation and number. PMID:10675306

Ashman, T L; Hitchens, M S

2000-02-01

70

Differential annual movement patterns in a migratory species: effects of experience and sexual maturation.  

PubMed

Some animals migrate long distances to exploit important seasonal food resources in the northern regions of the northern hemisphere, whilst avoiding winter starvation. Changes in the individual's age and navigational skills are likely to affect migration, which in turn influences the geographic distribution of individuals. Processes such as sexual maturation and navigational abilities are affected by age, and age is thus a key factor in understanding migration patterns and differences in distribution ranges. In the present study, we investigated the effects of age on the geographic distribution of a population of Lesser Black-backed Gulls Larus fuscus throughout its annual cycle, by analyzing a dataset of 19,096 records from 10,000 color-ringed gulls. In contrast to previous assumptions, the results showed that gulls were geographically segregated by age throughout the entire annual cycle, rather than showing a geographic age-related cline only in the wintering areas. This asymmetric distribution results from a reduction in the annual range of sexually mature gulls, and the differential distribution of mature and immature individuals (mature birds remained in more northern areas, compared to immature birds, throughout the annual cycle). Furthermore, although immature gulls travelled longer distances than adults, they initiated their fall migration with short movements, in contrast to adults that migrated using longer movements. The effects identified in this study explain the non-homogenous distribution of populations throughout the annual cycle, with wide implications for the development of effective human health policies and/or wildlife management strategies. PMID:21799853

Jorge, Paulo E; Sowter, David; Marques, Paulo A M

2011-01-01

71

Alteration of Sexual Reproduction and Genetic Diversity in the Kelp Species Laminaria digitata at the Southern Limit of Its Range  

PubMed Central

Adaptation to marginal habitats at species range-limits has often been associated with parthenogenetic reproduction in terrestrial animals and plants. Laboratory observations have shown that brown algae exhibit a high propensity for parthenogenesis by various mechanisms. The kelp Laminaria digitata is an important component of the ecosystem in Northern European rocky intertidal habitats. We studied four L. digitata populations for the effects of marginality on genetic diversity and sexual reproduction. Two populations were marginal: One (Locquirec, in Northern Brittany) was well within the geographic range, but was genetically isolated from other populations by large stretches of sandy beaches. Another population was at the range limits of the species (Quiberon, in Southern Brittany) and was exposed to much higher seasonal temperature changes. Microsatellite analyses confirmed that these populations showed decreased genetic and allelic diversity, consistent with marginality and genetic isolation. Sporophytes from both marginal populations showed greatly diminished spore-production compared to central populations, but only the southern-limit population (Quiberon) showed a high propensity for producing unreduced (2N) spores. Unreduced 2N spores formed phenotypically normal gametophytes with nuclear area consistent with ?2N DNA contents, and microsatellite studies suggested these were produced at least in part by automixis. However, despite this being the dominant path of spore production in Quiberon sporophyte individuals, the genetic evidence indicated the population was maintained mostly by sexual reproduction. Thus, although spore production and development showed the expected tendency of geographical parthenogenesis in marginal populations, this appeared to be a consequence of maladaptation, rather than an adaptation to, life in a marginal habitat. PMID:25019953

Oppliger, Luz Valeria; von Dassow, Peter; Bouchemousse, Sarah; Robuchon, Marine; Valero, Myriam; Correa, Juan A.; Mauger, Stéphane; Destombe, Christophe

2014-01-01

72

Novel microRNAs and microsatellite-like small RNAs in sexual and apomictic Boechera species.  

PubMed

Apomixis refers to plant asexual reproduction through seeds that give rise to progeny which are genotypically identical to the maternal parent. It has evolved from many different sexual taxa although the underlying genetic factors remain unknown. Previous analyses of the over-representation of transcription factors, in a comparison of microdissected ovules from apomictic and sexual Boechera, showed that many transcription factor mRNAs possessed microRNA (miRNAs) binding sites, thus pointing to miRNAs as potentially important factors that may be involved in the regulatory switch from sexual to apomictic reproduction. A microarray-based approach was used to identify (1) 673 microsatellitelike small RNAs (misRNAs) containing predominantly 2-7 repeats of (GAA)n/(CUU)n, (GCA)n/(CGU)n, (GGA)n/(CCU)n, (GGU)n/(CCA)n and (UGA)n/(ACU)n, and (2) 166 more typical non-repeat small RNAs. In total, 87 small RNAs were found to be located in cDNAs that could fold into stem-loop structures and thus represent miRNA molecules. In addition, 109 Boechera small RNAs including both misRNAs and non-repeat small RNAs, showed significant homology to 407 Arabidopsis thaliana small RNAs including the A. thaliana pollen-specific ath-miR5021. This indicates that only a fraction of the identified small RNAs are unique to Boechera. Ten small RNAs were validated using a Northern blot assay on flower and leaf tissues, eight of which showed flower-specific expression with varying abundance. The potential binding sites of many of the misRNAs and non-repeat small RNAs occur predominantly in exonic regions. This feature coupled with their flower-specific pattern of expression is suggestive of their probable role in post-transcriptional gene regulation. We propose that quantitative variation for misRNA target binding (and hence post-transcriptional gene regulation) could arise via microsatellite length polymorphisms occurring either in misRNA precursors or in their gene targets. PMID:25070713

Amiteye, Samuel; Corral, Jose M; Vogel, Heiko; Kuhlmann, Markus; Mette, Michael F; Sharbel, Timothy F

2013-01-01

73

Counting Ancestral Recombination Graph (ARG) Topologies In tracing or describing the history of species, individuals in a bi-sexual population and sequences subject to  

E-print Network

Counting Ancestral Recombination Graph (ARG) Topologies In tracing or describing the history of species, individuals in a bi-sexual population and sequences subject to recombination are used 3 graphs: The phylogeny, the pedigree and the ancestral recombination graph. These graphs have both a continuous aspect

Goldschmidt, Christina

74

Sexual Assault  

MedlinePLUS

... assault fact sheet Sexual assault fact sheet ePublications Sexual assault fact sheet Print this fact sheet Sexual assault ... assaulted? More information on sexual assault What is sexual assault? Sexual assault and abuse is any type of ...

75

Extravagant female sexual display in a Megaselia Rondani species (Diptera: Phoridae)  

PubMed Central

Abstract The behavior of females of a species of Megaselia is described. Females perch on leaves and occasionally "dance", fluttering their wings while rapidly running on the leaf surface. During this dance, they evert bright white abdominal sacs that apparently constitute part of a visual display to attract males. The evolutionary basis of these behaviors is discussed.

Porras, Wendy

2015-01-01

76

Notes: Sexual Dimorphism of Pelvic Fin Shape in Four Species of Catostomidae  

Microsoft Academic Search

Pelvic fin dimorphism was used as an external indicator of sex of northern hog suckers Hypentelium nigricans, shorthead redhorses Moxostoma macrolepidotum, longnose suckers Catostomus catostomus, and white suckers Catostomus commersoni. Sex of the four species ofcatostomids examined can be determined externally by two calculations: (1) linear regression of the seventh pelvic fin ray length on fork length, (2) ratio of

David R. Stanley

1988-01-01

77

Sexual Conflict and Sexually Antagonistic Coevolution in an Annual Plant  

PubMed Central

Background Sexual conflict theory predicts sexually antagonistic coevolution of reproductive traits driven by conflicting evolutionary interests of two reproducing individuals. Most studies of the evolutionary consequences of sexual conflicts have, however, to date collectively investigated only a few species. In this study we used the annual herb Collinsia heterophylla to experimentally test the existence and evolutionary consequences of a potential sexual conflict over onset of stigma receptivity. Methodology/Principal Findings We conducted crosses within and between four greenhouse-grown populations originating from two regions. Our experimental setup allowed us to investigate male-female interactions at three levels of geographic distances between interacting individuals. Both recipient and pollen donor identity affected onset of stigma receptivity within populations, confirming previous results that some pollen donors can induce stigma receptivity. We also found that donors were generally better at inducing stigma receptivity following pollen deposition on stigmas of recipients from another population than their own, especially within a region. On the other hand, we found that donors did worse at inducing stigma receptivity in crosses between regions. Interestingly, recipient costs in terms of lowered seed number after early fertilisation followed the same pattern: the cost was apparent only if the pollen donor belonged to the same region as the recipient. Conclusion/Significance Our results indicate that recipients are released from the cost of interacting with local pollen donors when crossed with donors from a more distant location, a pattern consistent with a history of sexually antagonistic coevolution within populations. Accordingly, sexual conflicts may have important evolutionary consequences also in plants. PMID:19421402

Madjidian, Josefin A.; Lankinen, Åsa

2009-01-01

78

Exposure to an environmental estrogen breaks down sexual isolation between native and invasive species  

PubMed Central

Environmental change can increase the likelihood of interspecific hybridization by altering properties of mate recognition and discrimination between sympatric congeners. We examined how exposure to an environmentally widespread endocrine-disrupting chemical (EDC), bisphenol A (BPA), affected visual communication signals and behavioral isolation between an introduced freshwater fish and a native congener (genus: Cyprinella). Exposure to BPA induced changes in the expression of male secondary traits as well as male and female mate choice, leading to an overall reduction in prezygotic isolation between congeners. Changes in female mate discrimination were not tightly linked to changes in male phenotypic traits, suggesting that EDC exposure may alter female choice thresholds independently of the effects of exposure on males. These findings indicate that environmental exposure to EDCs can lead to population declines via the erosion of species boundaries and by promoting the establishment and spread of non-native species via hybridization. PMID:23346234

Ward, Jessica L; Blum, Michael J

2012-01-01

79

Interspecific somatic hybrids between Cyclamen persicum and C. coum, two sexually incompatible species.  

PubMed

By applying polyethylene glycol (PEG)-mediated protoplast fusion, the first somatic hybrids were obtained between Cyclamen persicum (2n = 2x = 48) and C. coum (2n = 2x = 30)-two species that cannot be combined by cross breeding. Heterofusion was detected by double fluorescent staining with fluorescein diacetate and scopoletin. The highest heterofusion frequencies (of about 5%) resulted from a protocol using a protoplast density of 1 × 10(6)/mL and 40% PEG. The DNA content of C. coum was estimated for the first time by propidium iodide staining to be 14.7 pg/2C and was 4.6 times higher than that of C. persicum. Among 200 in vitro plantlets regenerated from fusion experiments, most resembled the C. coum parent, whereas only 5 plants showed typical C. persicum phenotypes and 46 had a deviating morphology. By flow cytometry, six putative somatic hybrids were identified. A species-specific DNA marker was developed based on the sequence of the 5.8S gene in the ribosomal nuclear DNA and its flanking internal transcribed spacers ITS1 and ITS2. The hybrid status of only one plant could be verified by the species-specific DNA marker as well as sequencing of the amplification product. RAPD markers turned out to be less informative and applicable for hybrid identification, as no clear additivity of the parental marker bands was observed. Chromosome counting in root tips of four hybrids revealed the presence of the 30 C. coum chromosomes and 2-41 additional ones indicating elimination of C. persicum chromosomes. PMID:22108718

Prange, Anika Nadja Sabine; Bartsch, Melanie; Meiners, Julia; Serek, Margrethe; Winkelmann, Traud

2012-04-01

80

Extensive variation in chromosome number and genome size in sexual and parthenogenetic species of the jumping-bristletail genus Machilis (Archaeognatha).  

PubMed

Parthenogenesis in animals is often associated with polyploidy and restriction to extreme habitats or recently deglaciated areas. It has been hypothesized that benefits conferred by asexual reproduction and polyploidy are essential for colonizing these habitats. However, while evolutionary routes to parthenogenesis are manifold, study systems including polyploids are scarce in arthropods. The jumping-bristletail genus Machilis (Insecta: Archaeognatha) includes both sexual and parthenogenetic species, and recently, the occurrence of polyploidy has been postulated. Here, we applied flow cytometry, karyotyping, and mitochondrial DNA sequencing to three sexual and five putatively parthenogenetic Eastern-Alpine Machilis species to investigate whether (1) parthenogenesis originated once or multiply and (2) whether parthenogenesis is strictly associated with polyploidy. The mitochondrial phylogeny revealed that parthenogenesis evolved at least five times independently among Eastern-Alpine representatives of this genus. One parthenogenetic species was exclusively triploid, while a second consisted of both diploid and triploid populations. The three other parthenogenetic species and all sexual species were diploid. Our results thus indicate that polyploidy can co-occur with parthenogenesis, but that it was not mandatory for the emergence of parthenogenesis in Machilis. Overall, we found a weak negative correlation of monoploid genome size (Cx) and chromosome base number (x), and this connection is stronger among parthenogenetic species alone. Likewise, monoploid genome size decreased with elevation, and we therefore hypothesize that genome downsizing could have been crucial for the persistence of alpine Machilis species. Finally, we discuss the evolutionary consequences of intraspecific chromosomal rearrangements and the presence of B chromosomes. In doing so, we highlight the potential of Alpine Machilis species for research on chromosomal and genome-size alterations during speciation. PMID:25505536

Gassner, Melitta; Dejaco, Thomas; Schönswetter, Peter; Marec, František; Arthofer, Wolfgang; Schlick-Steiner, Birgit C; Steiner, Florian M

2014-11-01

81

Extensive variation in chromosome number and genome size in sexual and parthenogenetic species of the jumping-bristletail genus Machilis (Archaeognatha)  

PubMed Central

Parthenogenesis in animals is often associated with polyploidy and restriction to extreme habitats or recently deglaciated areas. It has been hypothesized that benefits conferred by asexual reproduction and polyploidy are essential for colonizing these habitats. However, while evolutionary routes to parthenogenesis are manifold, study systems including polyploids are scarce in arthropods. The jumping-bristletail genus Machilis (Insecta: Archaeognatha) includes both sexual and parthenogenetic species, and recently, the occurrence of polyploidy has been postulated. Here, we applied flow cytometry, karyotyping, and mitochondrial DNA sequencing to three sexual and five putatively parthenogenetic Eastern-Alpine Machilis species to investigate whether (1) parthenogenesis originated once or multiply and (2) whether parthenogenesis is strictly associated with polyploidy. The mitochondrial phylogeny revealed that parthenogenesis evolved at least five times independently among Eastern-Alpine representatives of this genus. One parthenogenetic species was exclusively triploid, while a second consisted of both diploid and triploid populations. The three other parthenogenetic species and all sexual species were diploid. Our results thus indicate that polyploidy can co-occur with parthenogenesis, but that it was not mandatory for the emergence of parthenogenesis in Machilis. Overall, we found a weak negative correlation of monoploid genome size (Cx) and chromosome base number (x), and this connection is stronger among parthenogenetic species alone. Likewise, monoploid genome size decreased with elevation, and we therefore hypothesize that genome downsizing could have been crucial for the persistence of alpine Machilis species. Finally, we discuss the evolutionary consequences of intraspecific chromosomal rearrangements and the presence of B chromosomes. In doing so, we highlight the potential of Alpine Machilis species for research on chromosomal and genome-size alterations during speciation. PMID:25505536

Gassner, Melitta; Dejaco, Thomas; Schönswetter, Peter; Marec, František; Arthofer, Wolfgang; Schlick-Steiner, Birgit C; Steiner, Florian M

2014-01-01

82

sexual Assault sexual Assault  

E-print Network

sexual Assault sexual Assault if You Are a Victim of a sexual Assault 1. Get to a safe place. 2. Call out for help. 3. DiAl 6111 or ask someone to ring for you and state "sEXUAl AssAUlT" giving exact. if You Witness a sexual Assault 1. Everyone is asked to assist in making the campus a safe place by being

Hickman, Mark

83

Sexual reproduction in solitary corals: Synchronous gametogenesis and broadcast spawning in Paracyathus stearnsii  

Microsoft Academic Search

Samples of the temperate solitary coral Paracyathus stearnsii Verrill, 1869 were collected monthly or bimonthly from January 1977 to September 1978 off the California coast. This species is gonochoric and reproduces only sexually. Females produce a large number of small eggs (ca. 105 per polyp) in gametogenic synchrony and both sexes spawn between February and May. A small planktonic planula

Y. H. Fadlallah; J. S. Pearse

1982-01-01

84

Evidence for widespread cryptic sexual generations in apparently purely asexual Andricus gallwasps  

Microsoft Academic Search

Oak gallwasps (Hymenoptera, Cynipidae, Cynipini) are one of seven major animal taxa that commonly reproduce by cyclical parthenogenesis (CP). A major question in research on CP taxa is the frequency with which lineages lose their sexual generations, and diversify as purely asexual radiations. Most oak gallwasp species are only known from an asexual generation, and secondary loss of sex has

GRAHAM N. STONE; RACHEL J. ATKINSON; ANTONIS ROKAS; JOSÉ-LUIS N IEVES; GEORGE MELIKA; ZOLTAN ÁCS; GYÖRGY CSÓKA; ALEXANDER HA Y WARD; RICHARD BAILEY; CAROLINE BUCKEE; A. T. MC VEAN

2008-01-01

85

Sexual Health  

MedlinePLUS

... Parents can help their adolescent make healthy choices Sexual Health News & Information Understanding Sexual Health Public Health Reports ... infectious diseases, reproductive health and sexual violence prevention. Sexual Health Topics Sexually Transmitted Diseases Up-to-date information ...

86

Sexual dimorphism in animals  

NSDL National Science Digital Library

Many animals show sexual dimorphism, or differences between the males and females of that species. These are mostly physical differences, but other differences like songs in male and female birds can also be thought of as sexual dimorphism. Generally, males are more decorated and larger than females, but there are several species of animals in which the females are larger than the males.

Olivia Worland (Purdue University; Biological Sciences)

2008-05-23

87

Sexual activity diminishes male virility in two Coccinella species: consequences for female fertility and progeny development.  

PubMed

Male contributions, both chemical and behavioural, can influence female sperm usage and reproductive success. To determine whether such male factors are subject to depletion in Coccinella septempunctata and Coccinella transversalis, we tested the effects of male mating history on male virility, as estimated by measures of mating behaviour, female reproductive success and progeny fitness, with parental age held constant. Overt measures of male mating effort (wriggling duration, number of shaking bouts and total copula duration) all diminished from virgin to 5×mated males and were mirrored by concurrent declines in female fecundity and fertility(measured over 20 days). Paternal effects were also observed which diminished as a function of mating history, suggesting that transgenerational signals of male origin are also subject to depletion. Progeny of virgin fathers had higher rates of survival(C. transversalis) and faster development (both species) than progeny of 5×mated fathers. Seminal fluid proteins are known to have allohormonal properties and can stimulate female fecundity and fertility in a number of insects, making them strong candidates for depletion as a function of mating activity. However, it is also possible that sperm limitation and/or reduced tactile stimulation of females by multiple-mated males may have contributed to some of the observed effects. PMID:23590838

Michaud, J P; Bista, Mahadev; Mishra, Geetanjali; Omkar; Singh, Omkar

2013-10-01

88

How Do Beetles Reproduce?  

NSDL National Science Digital Library

Every living thing must be able to reproduce and make offspring. Most of us are familiar with how humans and mammals make babies, but do all creatures reproduce in the same way? Do insects, like the beetle, give birth to little insects? Also in: Français | Español

Jenny Drnevich

89

Reproducible epidemiologic research.  

PubMed

The replication of important findings by multiple independent investigators is fundamental to the accumulation of scientific evidence. Researchers in the biologic and physical sciences expect results to be replicated by independent data, analytical methods, laboratories, and instruments. Epidemiologic studies are commonly used to quantify small health effects of important, but subtle, risk factors, and replication is of critical importance where results can inform substantial policy decisions. However, because of the time, expense, and opportunism of many current epidemiologic studies, it is often impossible to fully replicate their findings. An attainable minimum standard is "reproducibility," which calls for data sets and software to be made available for verifying published findings and conducting alternative analyses. The authors outline a standard for reproducibility and evaluate the reproducibility of current epidemiologic research. They also propose methods for reproducible research and implement them by use of a case study in air pollution and health. PMID:16510544

Peng, Roger D; Dominici, Francesca; Zeger, Scott L

2006-05-01

90

Seasonal sexual segregation in two Thalassarche albatross species: competitive exclusion, reproductive role specialization or foraging niche divergence?  

Microsoft Academic Search

Sexual segregation by micro- or macrohabitat is common in birds, and usually attributed to size-mediated dominance and exclusion of females by larger males, trophic niche divergence or reproductive role speciali- zation. Our study of black-browed albatrosses, Thalassarche melanophrys, and grey-headed albatrosses, T. chrysostoma, revealed an exceptional degree of sexual segregation during incubation, with largely mutually exclusive core foraging ranges for

R. A. Phillips; J. R. D. Silk; B. Phalan; P. Catry; J. P. Croxall

2004-01-01

91

Genetic Diversity and Geographic Differentiation in the Threatened Species Dysosma pleiantha in China as Revealed by ISSR Analysis  

Microsoft Academic Search

Dysosma pleiantha, an important threatened medicinal plant species, is restricted in distribution to southeastern China. The species is capable\\u000a of reproducing both sexually and asexually. In this study, inter-simple sequence repeat marker data were obtained and analyzed\\u000a with respect to genetic variation and genetic structure. The extent of clonality, together with the clonal and sexual reproductive\\u000a strategies, varied among sites,

Min Zong; Hai-Long Liu; Ying-Xiong Qiu; Shu-Zhen Yang; Ming-Shui Zhao; Cheng-Xin Fu

2008-01-01

92

Migration and the Origin of Species Claus Rueffler  

E-print Network

to the biological relevant effect of migration in sexually reproducing plant and animal populations. Although stillMigration and the Origin of Species Claus Rueffler Mathematics and BioSciences Group Department. Messer, R. Schroeder and R. Wodak, eds. Migrations: Interdisciplinary Perspectives (2012), pp. 327

Hermisson, Joachim

93

Sexual Harassment and Sexual Bulllying  

MedlinePLUS

... Harassment and Sexual Bullying Print A A A Text Size What's in this article? What Are Sexual ... technology to harass someone sexually (like sending inappropriate text messages, pictures, or videos). Sometimes sexual harassment can ...

94

Male rat sexual behavior  

Microsoft Academic Search

The male rat's sexual behavior constitutes a highly ordered sequence of motor acts involving both striate and smooth muscles. It is spontaneously displayed by most adult male rats in the presence of a sexually receptive female. Although the behavior is important for the survival of the species it is not necessary for survival of the individual. In that way it

Anders Ågmo

1997-01-01

95

Spontaneous hybrids between native and exotic Rubus in the Western United States produce offspring both by apomixis and by sexual recombination  

PubMed Central

Facultative asexual reproduction is a trait commonly found in invasive species. With a combination of sexual and asexual reproductive modes, such species may adapt to new environments via sexual recombination during range expansion, while at the same time having the benefits of asexuality such as the maintenance of fitness effects that depend upon heterozygosity. In the Western United States, native species of Rubus (Rosaceae) reproduce sexually whereas exotic naturalized Rubus species reproduce by pseudogamous apomixis. We hypothesized that new asexual lineages of Rubus could arise from hybridization in this range. To detect hybridization between native and exotic Rubus, we genotyped 579 individuals collected across California, Oregon and Washington with eight nuclear microsatellites and two chloroplast markers. Principal Coordinate Analysis and Bayesian clustering revealed a limited amount of hybridization of the native R. ursinus with the exotic R. armeniacus and R. pensilvanicus, as well as cultivated varieties. Genetic distances between these hybrids and their offspring indicated that both R. ursinus × R. armeniacus and R. ursinus × R. pensilvanicus produced a mix of apomictic and sexual seeds, with sexual seeds being more viable. Although neither of these hybrid types is currently considered invasive, they model the early stages of evolution of new invasive lineages, given the potential for fixed heterosis and the generation of novel genotypes. The hybrids also retain the ability to increase their fitness via sexual recombination and natural selection. Mixed reproductive systems such as those described here may be an important step in the evolution of asexual invasive species. PMID:22850699

Clark, L V; Jasieniuk, M

2012-01-01

96

Spontaneous hybrids between native and exotic Rubus in the Western United States produce offspring both by apomixis and by sexual recombination.  

PubMed

Facultative asexual reproduction is a trait commonly found in invasive species. With a combination of sexual and asexual reproductive modes, such species may adapt to new environments via sexual recombination during range expansion, while at the same time having the benefits of asexuality such as the maintenance of fitness effects that depend upon heterozygosity. In the Western United States, native species of Rubus (Rosaceae) reproduce sexually whereas exotic naturalized Rubus species reproduce by pseudogamous apomixis. We hypothesized that new asexual lineages of Rubus could arise from hybridization in this range. To detect hybridization between native and exotic Rubus, we genotyped 579 individuals collected across California, Oregon and Washington with eight nuclear microsatellites and two chloroplast markers. Principal Coordinate Analysis and Bayesian clustering revealed a limited amount of hybridization of the native R. ursinus with the exotic R. armeniacus and R. pensilvanicus, as well as cultivated varieties. Genetic distances between these hybrids and their offspring indicated that both R. ursinus × R. armeniacus and R. ursinus × R. pensilvanicus produced a mix of apomictic and sexual seeds, with sexual seeds being more viable. Although neither of these hybrid types is currently considered invasive, they model the early stages of evolution of new invasive lineages, given the potential for fixed heterosis and the generation of novel genotypes. The hybrids also retain the ability to increase their fitness via sexual recombination and natural selection. Mixed reproductive systems such as those described here may be an important step in the evolution of asexual invasive species. PMID:22850699

Clark, L V; Jasieniuk, M

2012-11-01

97

Sexual Assault  

MedlinePLUS

Indian Health Service The Federal Health Program for American Indians and Alaska Natives Feedback Employee Resources • A to ... Assault Sexual assault is a significant problem affecting American Indians and Alaska Natives. Sexual assault refers to sexual ...

98

Sexual Assault  

MedlinePLUS

Sexual assault is any sexual activity to which you haven't freely given your consent. This includes completed ... trust, a friend, an acquaintance, or a stranger. Sexual assault can affect your health in many ways. It ...

99

Complexity and integration in sexual ornamentation: an example with carotenoid and melanin plumage pigmentation  

E-print Network

Complexity and integration in sexual ornamentation: an example with carotenoid and melanin plumage; melanins; modularity; sexual ornaments. Abstract Sexual ornaments often consist of several components mexicanus and common redpoll, Carduelis flammea) and a species with melanin-based sexual ornamentation

Badyaev, Alex

100

Examining Reproductive Strategies in an Asexually Reproducing Rotifer (Class Bdelloidea)  

Microsoft Academic Search

Nearly all multicelled organisms exhibit sexual reproduction. Rotifers of the class Bdelloidea, however, seem to be a notable exception to this pattern. No male bdelloid individuals have ever been observed and females apparently reproduce entirely through parthenogenesis. In this study, Philodina sp. was examined with the intent of addressing the following: 1) are bdelloids truly completely asexual? 2) if so,

Galbreath Kurt

1997-01-01

101

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

PubMed

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. PMID:24598810

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

2014-01-01

102

Sexual dimorphism and species differences in the neurophysiology and morphology of the acoustic communication system of two neotropical hylids  

Microsoft Academic Search

We examined auditory tuning and the morphology of the anatomical structures underlying acoustic communication in female Hyla microcephala and H. ebraccata and compared our findings to data from a previous study (Wilczynski et al. 1993) in which we showed species differences in\\u000a the traits that in males relate to differences in the species-typical calls. Female species differences in the best

Blinda E. McClelland; Walter Wilczynski; A. Stanley Rand

1997-01-01

103

Genetic Consequences of Tuber Versus Seed Sampling in Two Wild Potato Species Indigenous to the USA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wild potatoes reproduce in the wild (in situ) clonally by tubers or sexually by seeds. This study used model populations to assess the genetic consequences of sampling in situ tubers or in situ seeds for two indigenous potato species of the USA, Solanum stoloniferum PI 564039 (sto) and Solanum james...

104

Epigenetic variation in asexually reproducing organisms.  

PubMed

The role that epigenetic inheritance can play in adaptation may differ between sexuals and asexuals because (1) the dynamics of adaptation differ under sexual and asexual reproduction and the opportunities offered by epigenetic inheritance may affect these dynamics differently; and (2) in asexual reproduction epigenetic reprogramming mechanisms that are associated with meiosis can be bypassed, which could promote the buildup of epigenetic variation in asexuals. Here, we evaluate current evidence for an epigenetic contribution to adaptation in asexuals. We argue that two aspects of epigenetic variation should have particular relevance for asexuals, namely epigenetics-mediated phenotypic plasticity within and between generations, and heritable variation via stochastic epimutations. An evaluation of epigenetic reprogramming mechanisms suggests that some, but not all, forms of asexual reproduction enhance the likelihood of stable transmission of epigenetic marks across generations compared to sexual reproduction. However, direct tests of these predicted sexual-asexual differences are virtually lacking. Stable transmission of DNA methylation, transcriptomes, and phenotypes from parent to clonal offspring are demonstrated in various asexual species, and clonal genotypes from natural populations show habitat-specific DNA methylation. We discuss how these initial observations can be extended to demonstrate an epigenetic contribution to adaptation. PMID:24274255

Verhoeven, Koen J F; Preite, Veronica

2014-03-01

105

Internet Sexualities  

Microsoft Academic Search

\\u000a The term “internet sexuality” (or OSA, online sexual activities) refers to sexual-related content and activities observable\\u000a on the internet (cf. Adams, Oye, & Parker, 2003; Cooper, McLoughlin, & Campbell, 2000; Leiblum & Döring, 2002). It designates\\u000a a variety of sexual phenomena (e.g., pornography, sex education, sexual contacts) related to a wide spectrum of online services\\u000a and applications (e.g., websites, online

Nicola Döring

2010-01-01

106

The Effect of Temperature on Reproductive Characteristics of an Asexually Reproducing Rotifer (Class Bdelloidea)  

Microsoft Academic Search

Most organisms exhibit sexual reproduction. Rotifers of the class Bdelloidea, however, seem to be a notable exception to this pattern. No male bdelloid individuals have ever been observed, and females apparently reproduce entirely through parthenogenesis. Sexual reproduction occurs in rotifers of the class Monogononta, and in many cases it is induced by environmental cues (e.g. temperature, diet). In this study,

Kurt E. Galbreath

1997-01-01

107

Mating Signals Indicating Sexual Receptiveness Induce Unique Spatio-Temporal EEG Theta Patterns in an Anuran Species  

PubMed Central

Female mate choice is of importance for individual fitness as well as a determining factor in genetic diversity and speciation. Nevertheless relatively little is known about how females process information acquired from males during mate selection. In the Emei music frog, Babina daunchina, males normally call from hidden burrows and females in the reproductive stage prefer male calls produced from inside burrows compared with ones from outside burrows. The present study evaluated changes in electroencephalogram (EEG) power output in four frequency bands induced by male courtship vocalizations on both sides of the telencephalon and mesencephalon in females. The results show that (1) both the values of left hemispheric theta relative power and global lateralization in the theta band are modulated by the sexual attractiveness of the acoustic stimulus in the reproductive stage, suggesting the theta oscillation is closely correlated with processing information associated with mate choice; (2) mean relative power in the beta band is significantly greater in the mesencephalon than the left telencephalon, regardless of reproductive status or the biological significance of signals, indicating it is associated with processing acoustic features and (3) relative power in the delta and alpha bands are not affected by reproductive status or acoustic stimuli. The results imply that EEG power in the theta and beta bands reflect different information processing mechanisms related to vocal recognition and auditory perception in anurans. PMID:23285010

Fang, Guangzhan; Yang, Ping; Cui, Jianguo; Yao, Dezhong; Brauth, Steven E.; Tang, Yezhong

2012-01-01

108

Internet Sexualities  

NASA Astrophysics Data System (ADS)

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.”

Döring, Nicola

109

Sexual size dimorphism and sexual selection in turtles (order testudines)  

Microsoft Academic Search

This paper combines published and original data on sexual size dimorphism, reproductive behavior, and habitat types in turtles. Our major finding is that observed patterns of sexual size dimorphism correlate with habitat type and male mating strategy. (1) In most terrestrial species, males engage in combat with each other. Males typically grow larger than females. (2) In semiaquatic and “bottom-walking”

James F. Berry; Richard Shine

1980-01-01

110

Reproducibility in a multiprocessor system  

DOEpatents

Fixing a problem is usually greatly aided if the problem is reproducible. To ensure reproducibility of a multiprocessor system, the following aspects are proposed; a deterministic system start state, a single system clock, phase alignment of clocks in the system, system-wide synchronization events, reproducible execution of system components, deterministic chip interfaces, zero-impact communication with the system, precise stop of the system and a scan of the system state.

Bellofatto, Ralph A; Chen, Dong; Coteus, Paul W; Eisley, Noel A; Gara, Alan; Gooding, Thomas M; Haring, Rudolf A; Heidelberger, Philip; Kopcsay, Gerard V; Liebsch, Thomas A; Ohmacht, Martin; Reed, Don D; Senger, Robert M; Steinmacher-Burow, Burkhard; Sugawara, Yutaka

2013-11-26

111

Adolescent Sexuality.  

ERIC Educational Resources Information Center

This article offers a medical and psychosocial perspective of adolescent sexual development. Sub-types of sexual development are discussed as well as treatment implications for allied health providers. (Contains 38 references.) (Author)

Sharpe, Thomasina H.

2003-01-01

112

Sexual Health  

MedlinePLUS

... big part of being human. Love, affection and sexual intimacy all play a role in healthy relationships. ... both men and women. Factors that can affect sexual health include Fear of unplanned pregnancy Concerns about ...

113

Sexual hybridisation in crosses of cultivated Brassica species with the crucifers Erucastrum gallicum and Raphanus raphanistrum: Potential for gene introgression  

Microsoft Academic Search

Studies were conducted to investigate the crossability of the cultivated Brassica species, Brassica napus (oilseed rape),\\u000a B. rapa (turnip rape), and B. juncea (brown and oriental mustard), with two related cruciferous weeds that are abundant in\\u000a certain regions of Canada, Erucastrum gallicum (dog mustard) and Raphanus raphanistrum ssp. raphanistrum (wild radish). Seed\\u000a was produced without recourse to embryo rescue from

Eric Lefol; Ginette Séguin-Swartz; R. Keith Downey

1997-01-01

114

Population dynamics with a mixed type of sexual and asexual reproduction in a fluctuating environment  

PubMed Central

Background Carassius gibelio, a cyprinid fish from Eurasia, has the ability to reproduce both sexually and asexually. This fish is also known as an invasive species which colonized almost all continental Europe, most likely originating from Asia and Eastern Europe. Populations of both sexually and asexually reproducing individuals exist in sympatry. In this study we try to elucidate the advantages of such a mixed type of reproduction. We investigate the dynamics of two sympatric populations with sexual and asexual reproduction in a periodically fluctuating environment. We define an individual-based computational model in which genotypes are represented by L loci, and the environment is composed of L resources for which the two populations compete. Results Our model demonstrates advantageous population dynamics where the optimal percentage of asexual reproduction depends on selection strength, on the number of selected loci and on the timescale of environmental fluctuations. We show that the sexual reproduction is necessary for "generating" fit genotypes, while the asexual reproduction is suitable for "amplifying" them. The simulations show that the optimal percentage of asexual reproduction increases with the length of the environment stability period and decrease with the strength of the selection and the number of loci. Conclusions In this paper we addressed the advantages of a mixed type of sexual and asexual reproduction in a changing environment and explored the idea that a species that is able to adapt itself to environmental fluctuation can easily colonize a new habitat. Our results could provide a possible explanation for the rapid and efficient invasion of species with a variable ratio of sexual and asexual reproduction such as Carassius gibelio. PMID:22489797

2012-01-01

115

Sexual Intimacy After Sexual Assault or Sexual Abuse1  

E-print Network

Sexual Intimacy After Sexual Assault or Sexual Abuse1 Many survivors find that their sexual attitudes and reactions are impacted after a sexual assault or sexual abuse. While these effects are not permanent, they can be very frustrating as they can decrease the enjoyment of one's sexual life and intimacy

Machel, Hans

116

Variation in guenon skulls (II): sexual dimorphism  

Microsoft Academic Search

Patterns of size and shape sexual dimorphism in adult guenons were examined using a large sample of skulls from almost all living species. Within species, sexual dimorphism in skull shape follows the direction of size-related shape variation of adults, is proportional to differences in size, and tends to be larger in large-bodied species. Interspecific divergence among shape trajectories, which explain

Andrea Cardini; Sarah Elton

2008-01-01

117

Sexual conflict  

Microsoft Academic Search

Sexual conflict occurs when the genetic interests of males and females diverge. Recent evidence supporting the view that male and female genomes are in conflict has now revolutionized the way in which we interpret interactions between the sexes, and suggests that sexual conflict is a potent force in male–female coevolution. Here, we consider the nature of sexual conflict and what

Tracey Chapman; Göran Arnqvist; Jenny Bangham; Locke Rowe

2003-01-01

118

Long-Term Species, Sexual and Individual Variations in Foraging Strategies of Fur Seals Revealed by Stable Isotopes in Whiskers  

PubMed Central

Background Individual variations in the use of the species niche are an important component of diversity in trophic interactions. A challenge in testing consistency of individual foraging strategy is the repeated collection of information on the same individuals. Methodology/Principal Findings The foraging strategies of sympatric fur seals (Arctocephalus gazella and A. tropicalis) were examined using the stable isotope signature of serially sampled whiskers. Most whiskers exhibited synchronous ?13C and ?15N oscillations that correspond to the seal annual movements over the long term (up to 8 years). ?13C and ?15N values were spread over large ranges, with differences between species, sexes and individuals. The main segregating mechanism operates at the spatial scale. Most seals favored foraging in subantarctic waters (where the Crozet Islands are located) where they fed on myctophids. However, A. gazella dispersed in the Antarctic Zone and A. tropicalis more in the subtropics. Gender differences in annual time budget shape the seal movements. Males that do not perform any parental care exhibited large isotopic oscillations reflecting broad annual migrations, while isotopic values of females confined to a limited foraging range during lactation exhibited smaller changes. Limited inter-individual isotopic variations occurred in female seals and in male A. tropicalis. In contrast, male A. gazella showed large inter-individual variations, with some males migrating repeatedly to high-Antarctic waters where they fed on krill, thus meaning that individual specialization occurred over years. Conclusions/Significance Whisker isotopic signature yields unique long-term information on individual behaviour that integrates the spatial, trophic and temporal dimensions of the ecological niche. The method allows depicting the entire realized niche of the species, including some of its less well-known components such as age-, sex-, individual- and migration-related changes. It highlights intrapopulation heterogeneity in foraging strategies that could have important implications for likely demographic responses to environmental variability. PMID:22431988

Kernaléguen, Laëtitia; Cazelles, Bernard; Arnould, John P. Y.; Richard, Pierre; Guinet, Christophe; Cherel, Yves

2012-01-01

119

RAPID COMMUNICATION Sexually Mature Cuttlefish are Attracted  

E-print Network

. Invertebrate . Mollusk Introduction Many species of decapod cephalopods (cuttlefishes, squids) form large, near for Cephalopods, Galveston, Texas). Sexual maturity was determined behaviorally; sex was confirmed by necropsy

Boal, Jean

120

Sexual cannibalism as a manifestation of sexual conflict.  

PubMed

Sexual cannibalism is a well-known example for sexual conflict and has many facets that determine the costs and benefits for the cannibal and the victim. Here, I focus on species in which sexual cannibalism is a general component of a mating system in which males invest maximally in mating with a single (monogyny) or two (bigyny) females. Sexual cannibalism can be a male strategy to maximize paternity and a female strategy to prevent paternity monopolization by any or a particular male. Considerable variation exists between species (1) in the potential of males to monopolize females, and (2) in the success of females in preventing monopolization by males. This opens up exciting future possibilities to investigate sexually antagonistic coevolution in a largely unstudied mating system. PMID:25213095

Schneider, Jutta M

2014-11-01

121

SEXUAL ASSAULT AND SEXUAL HARASSMENT QUICK REFERENCE  

E-print Network

SEXUAL ASSAULT AND SEXUAL HARASSMENT QUICK REFERENCE Sexual Assault Definition ­ any form of sexual contact without both parties' voluntary consent. Contrary to what most people think, sexual assault. ­ Zvulony & Company ­ The Law of Sexual Assault in Canada. Sexual Harassment Definition ­ is comment

Thompson, Michael

122

Genetic structure of populations of two closely related brittle stars with contrasting sexual and asexual life histories, with observations on the genetic structure of a second asexual species  

Microsoft Academic Search

Ophiocoma pumila Lütken andOphiocomella ophiactoides (H. L. Clark) are morphologically similar brittle stars with contrasting life histories, the former obligately sexual, the latter fissiparous (capable of both sexual reproduction and asexual proliferation by binary fission). Electrophoretic analysis of five polymorphic enzymes was used to assess the genetic consequences of these differing life histories and provide a genetic perspective on the

P. V. Mladenov; R. H. Emson

1990-01-01

123

Female reproductive strategies in orangutans, evidence for female choice and counterstrategies to infanticide in a species with frequent sexual coercion  

PubMed Central

Intersexual conflicts over mating can engender antagonistic coevolution of strategies, such as coercion by males and selective resistance by females. Orangutans are exceptional among mammals for their high levels of forced copulation. This has typically been viewed as an alternative mating tactic used by the competitively disadvantaged unflanged male morph, with little understanding of how female strategies may have shaped and responded to this behaviour. Here, we show that male morph is not by itself a good predictor of mating dynamics in wild Bornean orangutans but that female conception risk mediated the occurrence and quality of male–female interactions. Near ovulation, females mated cooperatively only with prime flanged males who they encountered at higher rates. When conception risk was low, willingness to associate and mate with non-prime males increased. Our results support the hypothesis that, together with concealed ovulation, facultative association is a mechanism of female choice in a species in which females can rarely avoid coercive mating attempts. Female resistance, which reduced copulation time, may provide an additional mechanism for mate selection. However, coercive factors were also important as prime males were frequently aggressive to females and females used mating strategies consistent with infanticide avoidance. PMID:19812079

Knott, Cheryl Denise; Emery Thompson, Melissa; Stumpf, Rebecca M.; McIntyre, Matthew H.

2010-01-01

124

Sexual behaviour  

PubMed Central

Sexual health is not merely the absence of disease, but the ability to have informed, consensual, safe, respectful, and pleasurable sexual relationships. The majority of the population are sexually active, most with someone of the opposite sex. The frequency and range of sexual practices that people engage in declines with age, but for many, sexual activity continues well into later life. Different aspects of sexual health affect people at different times throughout their lives. As people in the UK tend to first have sex around the age of 16, but do not start living with a partner until much later, the avoidance of sexually transmitted infections and unplanned pregnancy is necessary for many for a number of years. As people get older, their sexual health needs change and they become more concerned with the impact of their general health on their ability to have sex. Some people experience non-volitional sex (sex against their will); although this occurs typically in late teenage it may affect women and men at any age and so requires consideration throughout life. As many people find it difficult to talk about sex and sexual health matters, health professionals should make sexual health enquiry a component of their holistic healthcare. PMID:24966786

Mercer, Catherine H.

2014-01-01

125

Sexual isolation in bacteria  

Microsoft Academic Search

Bacteria exchange genes rarely but are promiscuous in the choice of their genetic partners. Inter-specific recombination has the advantage of increasing genetic diversity and promoting dissemination of novel adaptations, but suffers from the negative effect of importing potentially harmful alleles from incompatible genomes. Bacterial species experience a degree of 'sexual isolation' from genetically divergent organisms ^ recombination occurs more frequently

Jacek Majewski

2001-01-01

126

Adolescent sexuality.  

PubMed

The consequences of adolescent sexual behavior are an enormous burden both for the adolescent and society. The problem is not that teens are sexually active but rather that they have little preparation and guidance in developing responsible sexual behavior. Developmentally, adolescents reach physical maturity before they are cognitively able to appreciate the consequences of their behavior. A teenager's primary source of information regarding sexuality is his or her peer group, all of whom are experiencing and reinforcing the same behaviors. The family, the major socializer of other behaviors, is not as powerful a force in shaping responsible sexual behavior because of parental discomfort with sex education and sexual discussions. This is the result of a social milieu in which sex is frequently portrayed but rarely linked with responsible behavior or accurate, nonjudgmental information. The pediatric practitioner is in an ideal position to intervene in these dynamics. In the office, the practitioner can provide accurate sexual information to both parents and adolescents, support parental-child communication on sexual issues, and provide appropriate services or referral. In the community, the practitioner can advocate for school-based sex education as well as act as an information resource. Finally, the practitioner can advocate for the health care needs for adolescents on a national level, supporting legislation that provides adolescents with information and access to services necessary to make responsible sexual decisions. PMID:3059299

Grant, L M; Demetriou, E

1988-12-01

127

Diploidy and the selective advantage for sexual reproduction in unicellular organisms  

Microsoft Academic Search

This article develops mathematical models describing the evolutionary dynamics of both asexually and sexually reproducing\\u000a populations of diploid unicellular organisms. The asexual and sexual life cycles are based on the asexual and sexual life\\u000a cycles in Saccharomyces cerevisiae, Baker’s yeast, which normally reproduces by asexual budding, but switches to sexual reproduction when stressed. The mathematical\\u000a models consider three reproduction pathways:

Maya Kleiman; Emmanuel Tannenbaum

2009-01-01

128

Operational sex ratio, sexual conflict and the intensity of sexual selection  

Microsoft Academic Search

Modern sexual selection theory indicates that reproductive costs rather than the operational sex ratio predict the intensity of sexual selection. We investigated sexual selection in the polygynandrous common lizard Lacerta vivipara. This species shows male aggression, causing high mating costs for females when adult sex ratios (ASR) are male- biased. We manipulated ASR in 12 experimental populations and quantified the

Patrick S. Fitze; Jean-François Le Galliard

2008-01-01

129

Sexual selection vs ecological causation in a sexually dimorphic caecilian, Schistometopum thomense (Amphibia Gymnophiona Caeciliidae)  

Microsoft Academic Search

Determination of the proximate cause of sexual dimorphism remains difficult, especially when trying to discriminate between sexual selection and ecological causation. A clear rejection of one of these hypotheses would advance the direction of future investigations, especially for cryptic and\\/or subterranean species. Sexual dimorphism in head size, but not body size, is confirmed for Schistometopum thomense, a fossorial caecilian from

M. Delêtre; G. J. Measey

2004-01-01

130

Summary. A single queen reproduces in the colonies of the ponerine ant Pachycondyla apicalis (87 75 workers, n = 85;  

E-print Network

to mate and store sperm. For example, in Harpegnathos saltator both queens and workers reproduce sexually though the degree of size divergence exhibited by queens and workers is similar to that in H. saltator

Danchin, Etienne

131

Clock genes and their genomic distributions in three species of salmonid fishes: Associations with genes regulating sexual maturation and cell cycling  

PubMed Central

Background Clock family genes encode transcription factors that regulate clock-controlled genes and thus regulate many physiological mechanisms/processes in a circadian fashion. Clock1 duplicates and copies of Clock3 and NPAS2-like genes were partially characterized (genomic sequencing) and mapped using family-based indels/SNPs in rainbow trout (RT)(Oncorhynchus mykiss), Arctic charr (AC)(Salvelinus alpinus), and Atlantic salmon (AS)(Salmo salar) mapping panels. Results Clock1 duplicates mapped to linkage groups RT-8/-24, AC-16/-13 and AS-2/-18. Clock3/NPAS2-like genes mapped to RT-9/-20, AC-20/-43, and AS-5. Most of these linkage group regions containing the Clock gene duplicates were derived from the most recent 4R whole genome duplication event specific to the salmonids. These linkage groups contain quantitative trait loci (QTL) for life history and growth traits (i.e., reproduction and cell cycling). Comparative synteny analyses with other model teleost species reveal a high degree of conservation for genes in these chromosomal regions suggesting that functionally related or co-regulated genes are clustered in syntenic blocks. For example, anti-müllerian hormone (amh), regulating sexual maturation, and ornithine decarboxylase antizymes (oaz1 and oaz2), regulating cell cycling, are contained within these syntenic blocks. Conclusions Synteny analyses indicate that regions homologous to major life-history QTL regions in salmonids contain many candidate genes that are likely to influence reproduction and cell cycling. The order of these genes is highly conserved across the vertebrate species examined, and as such, these genes may make up a functional cluster of genes that are likely co-regulated. CLOCK, as a transcription factor, is found within this block and therefore has the potential to cis-regulate the processes influenced by these genes. Additionally, clock-controlled genes (CCGs) are located in other life-history QTL regions within salmonids suggesting that at least in part, trans-regulation of these QTL regions may also occur via Clock expression. PMID:20670436

2010-01-01

132

Towards reproducible, scalable lateral molecular electronic devices  

SciTech Connect

An approach to reproducibly fabricate molecular electronic devices is presented. Lateral nanometer-scale gaps with high yield are formed in Au/Pd nanowires by a combination of electromigration and Joule-heating-induced thermomechanical stress. The resulting nanogap devices are used to measure the electrical properties of small numbers of two different molecular species with different end-groups, namely 1,4-butane dithiol and 1,5-diamino-2-methylpentane. Fluctuations in the current reveal that in the case of the dithiol molecule devices, individual molecules conduct intermittently, with the fluctuations becoming more pronounced at larger biases.

Durkan, Colm, E-mail: cd229@eng.cam.ac.uk; Zhang, Qian [Nanoscience Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA (United Kingdom)

2014-08-25

133

Towards reproducible, scalable lateral molecular electronic devices  

NASA Astrophysics Data System (ADS)

An approach to reproducibly fabricate molecular electronic devices is presented. Lateral nanometer-scale gaps with high yield are formed in Au/Pd nanowires by a combination of electromigration and Joule-heating-induced thermomechanical stress. The resulting nanogap devices are used to measure the electrical properties of small numbers of two different molecular species with different end-groups, namely 1,4-butane dithiol and 1,5-diamino-2-methylpentane. Fluctuations in the current reveal that in the case of the dithiol molecule devices, individual molecules conduct intermittently, with the fluctuations becoming more pronounced at larger biases.

Durkan, Colm; Zhang, Qian

2014-08-01

134

Positive correlation of trophic level and proportion of sexual taxa of oribatid mites (Acari: Oribatida) in alpine soil systems.  

PubMed

We investigated community structure, trophic ecology (using stable isotope ratios; (15)N/(14)N, (13)C/(12)C) and reproductive mode of oribatid mites (Acari, Oribatida) along an altitudinal gradient (2,050-2,900 m) in the Central Alps (Obergurgl, Austria). We hypothesized that (1) the community structure changes with altitude, (2) oribatid mites span over four trophic levels, (3) the proportion of sexual taxa increases with altitude, and (4) the proportion of sexual taxa increases with trophic level, i.e. is positively correlated with the ?(15)N signatures. Oribatid mite community structure changed with altitude indicating that oribatid mites occupy different niches at different altitudes. Oribatid mites spanned over 12 ?(15)N units, i.e. about four trophic levels, which is similar to lowland forest ecosystems. The proportion of sexually reproducing taxa increased from 2,050 to 2,900 m suggesting that limited resource availability at high altitudes favors sexual reproduction. Sexual taxa more frequently occurred higher in the food web indicating that the reproductive mode is related to nutrition of oribatid mites. Generally, oribatid mite community structure changed from being decomposer dominated at lower altitude to being dominated by fungal and lichen feeders, and predators at higher altitude. This supports the view that resources from dead organic material become less available with increasing altitude forcing species to feed on living resources such as fungi, lichens and nematodes. Our findings support the hypothesis that limited resource accessibility (at high altitudes) favors sexually reproducing species whereas ample resource supply (at lower altitudes) favors parthenogenetic species. PMID:24687174

Fischer, Barbara M; Meyer, Erwin; Maraun, Mark

2014-08-01

135

Sexual Abuse  

MedlinePLUS

... diseases Behavioral indicators Inappropriate sex-role relationship between victim and suspect Inappropriate, unusual, or aggressive sexual behavior How can I learn more? "Speaking the unspeakable: An interview about elder sexual assault with Holly Ramsey-Klawsnik, Ph.D" in nexus , ...

136

Sexual Sadism  

Microsoft Academic Search

Definitions of sexual sadism in ICD-10 and DSM-IV will be presented as well as the historical routes of the concept. Today studies on differently selected clinical samples reveal a different distribution of sexual sadism versus masochism with masochism prevailing in general especially outpatient psychiatric facilities, and sadism prevailing in forensic settings, thus corroborating the concept of two separated diagnoses sadism

Wolfgang Berner; Peter Berger; Andreas Hill

2003-01-01

137

Sexual selection  

Microsoft Academic Search

Competition over mates takes many forms and has far-reaching consequences for many organisms. Recent work suggests that relative reproductive rates of males and females, sperm competition and quality variation among mates affect the strength of sexual selection. Song, other display, body size, visual ornaments and material resource offerings are often sexually selected. There is much empirical evidence of mate choice,

Malte Andersson; Yoh Iwasa

1996-01-01

138

Sexual health  

PubMed Central

IN 2001 the government produced the first ever National strategy for sexual health and HIV.1 The strategy called for a broader role for general practice in the promotion of better sexual health. Surveys undertaken in the United Kingdom (UK) in recent years suggest that more people have more sexual partners than ever before. This has been associated with a rise in sexually transmitted infections (STIs). Screening and testing for Chlamydia trachomatis have become more widespread in the UK. Risk assessment and sexual history taking are described. They need to be carried out confidentially and non-judgmentally. Confidentiality training for all staff, including a requirement to sign confidentiality statements, is recommended. Partner notification can be done in a variety of different settings including general practice. A new course for those working in primary care has been devised, aiming to equip participants with the basic knowledge, skills, and attitudes for the effective management of STIs. PMID:15113524

Graham, Anna

2004-01-01

139

Reproducible Bioinformatics Research for Biologists  

Technology Transfer Automated Retrieval System (TEKTRAN)

This book chapter describes the current Big Data problem in Bioinformatics and the resulting issues with performing reproducible computational research. The core of the chapter provides guidelines and summaries of current tools/techniques that a noncomputational researcher would need to learn to pe...

140

Reproducible Research in Computational Science  

PubMed Central

Computational science has led to exciting new developments, but the nature of the work has exposed limitations in our ability to evaluate published findings. Reproducibility has the potential to serve as a minimum standard for judging scientific claims when full independent replication of a study is not possible. PMID:22144613

Peng, Roger D.

2012-01-01

141

Reproducible research in computational science.  

PubMed

Computational science has led to exciting new developments, but the nature of the work has exposed limitations in our ability to evaluate published findings. Reproducibility has the potential to serve as a minimum standard for judging scientific claims when full independent replication of a study is not possible. PMID:22144613

Peng, Roger D

2011-12-01

142

Principles of competitive exclusion for discrete populations with reproducing juveniles and adults  

Microsoft Academic Search

We invent notions of dominance and weak dominance for discrete multi-species systems with competing juveniles and adults. In this model, both the juveniles and adults are allowed to reproduce. We prove that, a dominant species drives the dominated species to extinction. In discrete juvenile-adult systems that do not allow juveniles to reproduce, it is known that weak dominance is equivalent

John E. Franke; Abdul-Aziz Yakubu

1997-01-01

143

Sex in Cheese: Evidence for Sexuality in the Fungus Penicillium roqueforti  

PubMed Central

Although most eukaryotes reproduce sexually at some moment of their life cycle, as much as a fifth of fungal species were thought to reproduce exclusively asexually. Nevertheless, recent studies have revealed the occurrence of sex in some of these supposedly asexual species. For industrially relevant fungi, for which inoculums are produced by clonal-subcultures since decades, the potentiality for sex is of great interest for strain improvement strategies. Here, we investigated the sexual capability of the fungus Penicillium roqueforti, used as starter for blue cheese production. We present indirect evidence suggesting that recombination could be occurring in this species. The screening of a large sample of strains isolated from diverse substrates throughout the world revealed the existence of individuals of both mating types, even in the very same cheese. The MAT genes, involved in fungal sexual compatibility, appeared to evolve under purifying selection, suggesting that they are still functional. The examination of the recently sequenced genome of the FM 164 cheese strain enabled the identification of the most important genes known to be involved in meiosis, which were found to be highly conserved. Linkage disequilibria were not significant among three of the six marker pairs and 11 out of the 16 possible allelic combinations were found in the dataset. Finally, the detection of signatures of repeat induced point mutations (RIP) in repeated sequences and transposable elements reinforces the conclusion that P. roqueforti underwent more or less recent sex events. In this species of high industrial importance, the induction of a sexual cycle would open the possibility of generating new genotypes that would be extremely useful to diversify cheese products. PMID:23185400

Ropars, Jeanne; Dupont, Joëlle; Fontanillas, Eric; Rodríguez de la Vega, Ricardo C.; Malagnac, Fabienne; Coton, Monika; Giraud, Tatiana; López-Villavicencio, Manuela

2012-01-01

144

The nature of sexual reinforcement.  

PubMed Central

Sexual reinforcers are not part of a regulatory system involved in the maintenance of critical metabolic processes, they differ for males and females, they differ as a function of species and mating system, and they show ontogenetic and seasonal changes related to endocrine conditions. Exposure to a member of the opposite sex without copulation can be sufficient for sexual reinforcement. However, copulatory access is a stronger reinforcer, and copulatory opportunity can serve to enhance the reinforcing efficacy of stimulus features of a sexual partner. Conversely, under certain conditions, noncopulatory exposure serves to decrease reinforcer efficacy. Many common learning phenomena such as acquisition, extinction, discrimination learning, second-order conditioning, and latent inhibition have been demonstrated in sexual conditioning. These observations extend the generality of findings obtained with more conventional reinforcers, but the mechanisms of these effects and their gender and species specificity remain to be explored. PMID:8354970

Crawford, L L; Holloway, K S; Domjan, M

1993-01-01

145

Sexual Health  

MedlinePLUS

... from a disease or health condition. The Most Common Types of Sexual Problems in Older Adults For women, age-related changes due to menopause include: lack of interest difficulty with lubrication inability to reach a climax ( ...

146

Healthy Sexuality  

MedlinePLUS

... about sexual function as described by Masters and Johnson in the mid-1960s. They described 4 stages, ... returns to its unstimulated state. Since Masters and Johnson, other researchers have modified the original concept with ...

147

Teenage Sexuality  

MedlinePLUS

... Books Four Stages of Coming Out Staying Out Late and Curfews Date Rape Healthy Children Radio: Acne and Common Skin Problems of Adolescents (Audio) Birth Control for Sexually Active Teens Dangers ...

148

Sexual Difficulties  

MedlinePLUS

... sex. Medicines: Many commonly prescribed drugs have sexual side effects. For instance, some drugs used to treat depression can suppress libido. Surgery: Women who have undergone breast cancer surgery, for example, may feel less desirable or ...

149

Monte Carlo simulations of sexual reproduction  

NASA Astrophysics Data System (ADS)

Modifying the Redfield model of sexual reproduction and the Penna model of biological aging, we compare reproduction with and without recombination in age-structured populations. In constrast to Redfield and in agreement with Bernardes we find sexual reproduction to be preferred to asexual one. In particular, the presence of old but still reproducing males helps the survival of younger females beyond their reproductive age.

Stauffer, D.; de Oliveira, P. M. C.; de Oliveira, S. Moss; dos Santos, R. M. Zorzenon

1996-02-01

150

Sexuality and Sexual Rights in Muslim Societies  

Microsoft Academic Search

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

Liz Ercevik Amado

2009-01-01

151

Detecting sexual conflict and sexually antagonistic coevolution  

E-print Network

Detecting sexual conflict and sexually antagonistic coevolution Locke Rowe1,2,* and Troy Day3,4 1 by providing an operational definition of sexual conflict that applies to both inter- and intralocus conflict approaches for detecting interlocus sexual conflict and resultant sexually antagonistic coevolution. We

Day, Troy

152

SEXUAL MISCONDUCT/SEXUAL ASSAULT POLICY  

E-print Network

SEXUAL MISCONDUCT/SEXUAL ASSAULT POLICY Office of Equal Opportunity Purpose: To establish a work and educational environment at Tufts University that is free from Sexual Misconduct, which includes sexual harassment, sex/gender discrimination, sexual assault, rape and other gender-based misconduct, through

Dennett, Daniel

153

Sexual selection and mating patterns in a mammal with female-biased sexual size dimorphism  

Microsoft Academic Search

In mammals, species with highly male-biased sexual size dimorphism tend to have high variance in male reproductive success. However, little information is available on patterns of sexual selection, variation in male and female reproductive success, and body size and mating success in species with female-biased size dimorphism. We used parentage data from microsatellite DNA loci to examine these issues in

Albrecht I. Schulte-Hostedde; John S. Millar; H. Lisle Gibbsb

2004-01-01

154

Comparative Transcriptional Analysis of Asexual and Sexual Morphs Reveals Possible Mechanisms in Reproductive Polyphenism of the Cotton Aphid  

PubMed Central

Aphids, the destructive insect pests in the agriculture, horticulture and forestry, are capable of reproducing asexually and sexually upon environmental change. However, the molecular basis of aphid reproductive mode switch remains an enigma. Here we report a comparative analysis of differential gene expression profiling among parthenogenetic females, gynoparae and sexual females of the cotton aphid Aphis gossypii, using the RNA-seq approach with next-generation sequencing platforms, followed by RT-qPCR. At the cutoff criteria of fold change ?2 and P<0.01, we identified 741 up- and 879 down-regulated genes in gynoparae versus parthenogenetic females, 2,101 up- and 2,210 down-regulated genes in sexual females compared to gynoparae, and 1,614 up- and 2,238 down-regulated genes in sexual females relative to parthenogenetic females. Gene ontology category and KEGG pathway analysis suggest the involvement of differentially expressed genes in multiple cellular signaling pathways into the reproductive mode transition, including phototransduction, cuticle composition, progesterone-mediated oocyte maturation and endocrine regulation. This study forms a basis for deciphering the molecular mechanisms underlying the shift from asexual to sexual reproduction in the cotton aphid. It also provides valuable resources for future studies on this host-alternating aphid species, and the insight into the understanding of reproductive mode plasticity in different aphid species. PMID:24915491

Jiang, Feng; Guo, Wei; Zhou, Shu-Tang

2014-01-01

155

Apomictic and sexual pearl millet X Pennisetum squamulatum hybrids  

SciTech Connect

Pennisetum squamulatum Fresen, an apomictic East African grass (2n = 54) was crossed to tetraploid (2n = 28) sexual pearl millet, P. americanum L. Leeke to study the potential for germplasm exchange. Twenty interspecific hybrids (2n = 41) with 14 pearl millet and 27 P. squamulatum chromosomes were obtained. All resembled P. squamulatum in perennial growth habit and inflorescence characteristics and resembled pearl millet in leafiness and pencillate anther tips. Seventeen of these hybrids were more vigorous than either parent. The most common chromosome association at metaphase I was 18 bivalents plus 5 univalents. At anaphase I and telophase I laggards, fragments, and unequal chromosome distribution were observed. Fifteen of 17 interspecific hybrids reproduced by facultative apomixis, one was sexual and one was an obligate apomict. Ovules with aposporous embryo sacs ranged from 1 to 93% in facultative apomictic plants. Morphological characteristics and chromosome numbers of open-pollinated progeny from the apomictic interspecific hybrid were identical to those of the seed parent indicating obligate apomictic reproduction. Both sexual and apomictic hybrids were partially male fertile with pollen stainability ranging from 29 percent to 79 percent and seed-set ranging from 1 to 60 seed per inflorescence under open-pollination. Development of fertile apomictic pearl millet-P. squamulatum interspecific hybrids appears to be a very useful tool for the transfer of genes for apomixis from the wild species to pearl millet.

Dujardin, M.; Hanna, W.W.

1983-01-01

156

Healthy Aging -- Sexual Health  

MedlinePLUS

... Healthy Aging This information in Spanish ( en español ) Sexual health More information on sexual health Many older women ... Protecting yourself Return to top More information on Sexual health Read more from womenshealth.gov Sexually Transmitted Infections ...

157

Sexual Dysfunction and Infertility  

MedlinePLUS

... org • URL www.asrm.org PATIENT FACT SHEET Sexual Dysfunction and Infertility You probably don't realize ... of this, sexual problems can arise. What is sexual dysfunction? Doctors divide normal sexual function into 3 ...

158

Reproducibility of brain ADC histograms  

Microsoft Academic Search

The aim of this study was to assess the effect of differences in acquisition technique on whole-brain apparent diffusion coefficient (ADC) histogram parameters, as well as to assess scan–rescan reproducibility. Diffusion-weighted imaging (DWI) was performed in 7 healthy subjects with b-values 0–800, 0–1000, and 0–1500 s\\/mm 2 and fluid-attenuated inversion recovery (FLAIR) DWI with b-values 0–1000 s\\/mm 2. All sequences were repeated

Stefan C. A. Steens; Faiza Admiraal-Behloul; Jorrit A. Schaap; Frank G. C. Hoogenraad; Claudia A. M. Wheeler-Kingshott; Saskia le Cessie; Paul S. Tofts; Mark A. van Buchem

2004-01-01

159

Sexual sadism.  

PubMed

Definitions of sexual sadism in ICD-10 and DSM-IV will be presented as well as the historical routes of the concept. Today studies on differently selected clinical samples reveal a different distribution of sexual sadism versus masochism with masochism prevailing in general especially outpatient psychiatric facilities, and sadism prevailing in forensic settings, thus corroborating the concept of two separated diagnoses sadism versus masochism. In forensic settings the diagnosis of a sadistic character disorder (sadistic personality disorder [SPD] according DSM-III-R) is found to a much higher degree than in other clinical samples (50-fold). Our own follow-up study on a forensic sample implies that sadism as a paraphilia is of relevance for relapse-rates of sex-offenders. Symptoms of SPD can be combined with sexual sadism, or occur independently. This may corroborate arguments in favor of a dimensional concept of sexual sadism. Symptoms of SPD may then be a sign of generalization of sadistic traits at least in some cases. A concept of two factors contributing to sadistic pleasure is suggested, one taking the aspect of bodily gratification by sexual-aggressive stimuli as decisive, and the other taking inner representation of hostile objects into consideration (stressing the antisocial-anger-rage aspect). PMID:12971180

Berner, Wolfgang; Berger, Peter; Hill, Andreas

2003-08-01

160

The Evolution of Sex Asexual v. Sexual Reproduction  

E-print Network

1 The Evolution of Sex Asexual v. Sexual Reproduction In a game between asexual and sexual reproduction, asexual reproduction always wins -- other things being equal. Hamilton's computer model of reproduction: Asexual Reproduction · Binary fission - The method by which bacteria reproduce. The circular DNA

Dever, Jennifer A.

161

Interference of asexual and sexual reproduction in the green hydra  

Microsoft Academic Search

The green hydra, Hydra viridissima, has three sexes: hermaphrodite, male, and female. I investigated the reproductive strategies of the green hydra and the\\u000a relationship between asexual budding and sexual reproduction. The proportion of mature individuals in the asexually reproducing\\u000a population increased with increasing temperature. Sexual reproduction did not interrupt asexual budding in hermaphrodites\\u000a or males; sexual reproduction did interrupt asexual

Anita Kaliszewicz

2011-01-01

162

Adolescent sexual activity.  

PubMed

Adolescents are becoming sexually active at younger ages. One half of the adolescents in the United States are sexually active. This article reviews adolescent sexual activity, including rates of sexual activity, sexual practices, gay and lesbian youth, and factors affecting the initiation of sexual activity. In addition, adolescent pregnancy, with possible outcomes and effects on teen parents and their offspring, is discussed. PMID:8299296

Braverman, P K; Strasburger, V C

1993-11-01

163

Student Sexual Misconduct Policy  

E-print Network

Student Sexual Misconduct Policy 2014-2015 #12;1 BOSTON COLLEGE STUDENT SEXUAL MISCONDUCT POLICY INDEX I. INTRODUCTION II. BUILDING AN EDUCATIONAL ENVIRONMENT FREE FROM SEXUAL MISCONDUCT III. PROHIBITED BEHAVIOR a. Definitions i. Sexual Misconduct ii. Sexual Harassment iii. Sexual Assault iv. Consent

Huang, Jianyu

164

Sexual assault.  

PubMed

Sexual assault continues to represent the most rapidly growing violent crime in America. Vital legal reforms are underway, but statistics prove a persistent rise in rape incidence with poor conviction rates. This knowledge, along with the vast multitude of emotional sequelae of rape and self-perceived inferior legal status of women, results in a high percentage of unreported cases. It is imperative that health care providers understand the horrific nature of sexual assault in order to provide appropriate care. All medical care personnel involved in the care of potential rape victims should be briefed in historic and modern legalities of sexual assault. Specific training in emergent and chronic care, both physical and mental, in conjunction with an understanding of rape legislation is vital if health care professionals are to appropriately care for victims of rape. PMID:8414312

Dupre, A R; Hampton, H L; Morrison, H; Meeks, G R

1993-09-01

165

Quantizations from reproducing kernel spaces  

SciTech Connect

The purpose of this work is to explore the existence and properties of reproducing kernel Hilbert subspaces of L{sup 2}(C,d{sup 2}z/?) based on subsets of complex Hermite polynomials. The resulting coherent states (CS) form a family depending on a nonnegative parameter s. We examine some interesting issues, mainly related to CS quantization, like the existence of the usual harmonic oscillator spectrum despite the absence of canonical commutation rules. The question of mathematical and physical equivalences between the s-dependent quantizations is also considered. -- Highlights: ? We discuss in detail an interesting decomposition of L{sup 2}, in terms of ladder operators. ? We consider coherent states on this structure and we use them for quantization. ? We show how this structure is related with non hermitian quantum mechanics. ? We consider the relation between different schemes of quantizations.

Twareque Ali, S., E-mail: stali@mathstat.concordia.ca [Department of Mathematics and Statistics, Concordia University, Montréal, Québec, Canada H3G 1M8 (Canada); Bagarello, F., E-mail: fabio.bagarello@unipa.it [Dieetcam, Facoltà di Ingegneria, Università di Palermo, I-90128 Palermo (Italy); Pierre Gazeau, Jean, E-mail: gazeau@apc.univ-paris7.fr [Laboratoire APC, Université Paris 7-Denis Diderot, 10, rue A. Domon et L. Duquet, 75205 Paris Cedex 13 (France)

2013-05-15

166

TEXAS TECH UNIVERSITY Sexual Misconduct Information Packet  

E-print Network

Assault, Sexual Violence, Sexual Harassment of Conduct, "Sexual Misconduct" is any of the following: SEXUAL HARASSMENT "Unwelcome verbal, written TEXAS TECH UNIVERSITY Sexual Misconduct Information Packet Sexual

Zhuang, Yu

167

7 CFR 800.166 - Reproducing certificates.  

Code of Federal Regulations, 2010 CFR

...AGRICULTURE GENERAL REGULATIONS Official Certificates § 800.166 Reproducing certificates. Official certificates may be photo copied or similarly reproduced. (Approved by the Office of Management and Budget under control number 0580-0011)...

2010-01-01

168

The reproducibility of patch tests.  

PubMed

There is conflicting evidence regarding the reproducibility of patch testing. Discordant results have been reported in up to 44% of cases. The clinical relevance of these discordant patch tests has not been previously assessed. We studied 383 consecutive patients receiving simultaneous duplicate patch testing on opposite sides of the upper back with 10 allergens from the European standard series. Completely discordant patch tests-a negative test on one side with a positive test on the opposite side-were recorded in 30 (8%) patients. Two patients had discordant tests to two of the allergens; 28 had discordant reactions to one allergen. Completely discordant tests were recorded for nickel in 10 (3%) patients, balsam of Peru in two (0.5%), thiomersal in one (0.3%), cobalt in four (1%), paraphenylenediamine in three (0.8%), fragrance mix in two (0.5%), formaldehyde in four (1%), potassium dichromate in two (0.5%), lanolin in three (0.8%) and Kathon CG in one (0.3%). Of those patients with completely discordant patch tests, the allergen was deemed to be a true positive in 11 (3% of total) cases and of possible relevance in a further three. The allergen was felt to be relevant to the presenting complaint in seven (2% of total) patients. PMID:10215776

Bourke, J F; Batta, K; Prais, L; Abdullah, A; Foulds, I S

1999-01-01

169

Natural and sexual selection on color patterns in poeciliid fishes  

Microsoft Academic Search

Synopsis  In poeciliid fishes, sexual dichromism is associated with larger size and larger broods, but there is no relationship between\\u000a sexual size dimorphism and sexual dichromism, or between degree of dichromism and color pattern polymorphism. Factors are\\u000a discussed which influence the evolution of color pattern polymorphisms, sexual dimorphism and dichromism. Detailed studies\\u000a of South American species have shown that the color

John A. Endler

1983-01-01

170

Reproducibility of pain measurement and pain perception  

Microsoft Academic Search

The reproducibility of both the conscious experience of pain and the reproducibility of psychophysical assessments of pain remain critical, yet poorly characterized factors in pain research and treatment. To assess the reproducibility of both the pain experience and two methods of pain assessment, 15 subjects evaluated experimental heat pain during four weekly sessions. In each session, both brief (5s) and

Elisa M. Rosier; Michael J. Iadarola; Robert C. Coghill

2002-01-01

171

Puberty and adolescent sexuality.  

PubMed

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. PMID:23998672

Fortenberry, J Dennis

2013-07-01

172

Sexual size dimorphism in anurans.  

PubMed Central

Several hypotheses have been proposed to explain the direction and extent of sexual size dimorphism in anurans (in which males are usually smaller than females) as a result of sexual selection. Here, we present an analysis to test the hypothesis that sexual dimorphism in anurans is largely a function of differences between the sexes in life-history strategies. Morphological and demographic data for anurans were collected from the literature, and the mean size and age in each sex were calculated for 51 populations, across 30 species and eight genera. Comparisons across 14 Rana species, eight Bufo species and across the genera showed a highly significant relationship between size dimorphism, measured using the female-male size ratio, and mean female-male age difference. A comparison of a subset of 17 of these species for which phylogenetic information was available, using the method of independent contrasts, yielded a similar result. These results indicate that most of the variation in size dimorphism in the anura can be explained in terms of differences in the age structure between the sexes in breeding populations. If sexual selection has an effect on size dimorphism in anurans, it is likely to be only a secondary one. PMID:12495496

Monnet, Jean-Matthieu; Cherry, Michael I

2002-01-01

173

Sexual Selection IV: Sperm Competition  

E-print Network

Sexual Selection IV: Sperm Competition BIO3176 - University of Ottawa Prof. Gabriel Blouin and extra-pair paternity are common, even in socially monogamous species Sperm Competition 2 Proof of Sperm Competition Harcourt et al 1981 Nature 293: 55-57 3 · Primates · Selection on ejaculate volume Proof of Sperm

Blouin-Demers, Gabriel

174

Variation in guenon skulls (II): sexual dimorphism.  

PubMed

Patterns of size and shape sexual dimorphism in adult guenons were examined using a large sample of skulls from almost all living species. Within species, sexual dimorphism in skull shape follows the direction of size-related shape variation of adults, is proportional to differences in size, and tends to be larger in large-bodied species. Interspecific divergence among shape trajectories, which explain within species sex differences, are small (i.e., trajectories of most species are nearly parallel). Thus, changes in relative proportions of skull regions that account for the distinctive shape of females and males are relatively conserved across species, and their magnitude largely depends on differences in size between sexes. A conservative pattern of size-related sexual dimorphism and a model of interspecific divergence in shape which strongly reflects size differences suggest a major role of size and size-related shape variation in the guenon radiation. It is possible that in the guenons, as in the neotropical primates (with whom they have obvious parallels), size has helped to determine morphological change along lines of least evolutionary resistance, influencing sexual dimorphism. In Miopithecus and Erythrocebus, the smallest and largest guenon genera, it is likely that the interaction of ecology and size contributes significantly to patterns of sexual dimorphism. The results of this study thus emphasise the need to consider allometry and size alongside ecology and behaviour when examining primate sexual dimorphism. PMID:18191178

Cardini, Andrea; Elton, Sarah

2008-05-01

175

Sexuality and Young Children.  

ERIC Educational Resources Information Center

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…

Honig, Alice Sterling

2000-01-01

176

Sexual and Cleaning Behavior and Related Morphology in the Genus Cerocoma (Coleoptera: Meloidae)  

Microsoft Academic Search

The study of sexual behavior has been largely utilized in phylogenetic analyses of Meloidae beetles. Sexual behavior of the tribe Cerocomini is almost unknown, even though the genus Cerocoma shows the most striking sexual dimorphism in the family. In this paper, the sexual behavior of five species, C. (Cerocoma) adamovichiana, C. (C.) graeca, C. (C.) schaefferi, C. (Metacerocoma) schreberi, and

Federica Turco; Andrea Di Giulio; Marco A. Bologna

2003-01-01

177

[Adolescent sexuality].  

PubMed

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. PMID:21877398

Calero, Juan del Rey

2010-01-01

178

Unrecognized coral species diversity masks differences in functional ecology.  

PubMed

Porites corals are foundation species on Pacific reefs but a confused taxonomy hinders understanding of their ecosystem function and responses to climate change. Here, we show that what has been considered a single species in the eastern tropical Pacific, Porites lobata, includes a morphologically similar yet ecologically distinct species, Porites evermanni. While P. lobata reproduces mainly sexually, P. evermanni dominates in areas where triggerfish prey on bioeroding mussels living within the coral skeleton, thereby generating asexual coral fragments. These fragments proliferate in marginal habitat not colonized by P. lobata. The two Porites species also show a differential bleaching response despite hosting the same dominant symbiont subclade. Thus, hidden diversity within these reef-builders has until now obscured differences in trophic interactions, reproductive dynamics and bleaching susceptibility, indicative of differential responses when confronted with future climate change. PMID:24335977

Boulay, Jennifer N; Hellberg, Michael E; Cortés, Jorge; Baums, Iliana B

2014-02-01

179

Effects of Sexual Selection Upon Sperm Morphology and Sexual Skin Morphology in Primates  

Microsoft Academic Search

We review possible effects of sexual selection upon sperm morphology, and sexual skin morphology, in primates. Comparative morphometric studies, involving 31 species representing 21 primate genera, revealed a positive relationship between volume of the sperm midpiece, occurrences of multiple partner matings by females, and large relative testes sizes, which indicate sperm competition. The midpiece houses the mitochondria required to power

Alan F. Dixson; Matthew J. Anderson

2004-01-01

180

Childhood sexual abuse, adolescent sexual behaviors and sexual revictimization  

Microsoft Academic Search

Objective: The aims of this study were to examine the extent to which exposure to childhood sexual abuse (CSA) was associated with increased rates of sexual risk taking behaviors and sexual revictimization during adolescence.Method: A birth cohort of 520 New Zealand born young women was studied at regular intervals from birth to the age of 18. At age 18 retrospective

David M. Fergusson; L. John Horwood; Michael T. Lynskey

1997-01-01

181

Your Sexual Health  

MedlinePLUS

... during treatment of a sexual problem? • Glossary Your Sexual Health 4. Sexual pain disorder What are desire problems? ... by women. A lack of desire before having sex is normal for some women. They may not ...

182

Reproducible EnzymeReproducible Enzyme Assembly and CatalyticAssembly and Catalytic  

E-print Network

Reproducible EnzymeReproducible Enzyme Assembly and CatalyticAssembly and Catalytic Activity Accomplishments #12;Reproducible Enzyme Assembly and CatalyticReproducible Enzyme Assembly and Catalytic Activity in Reusable BioMEMSActivity in Reusable BioMEMS Accomplishment Pro-tagged Pfs enzymes are spatially assembled

Rubloff, Gary W.

183

Sexual size dimorphism, sex ratio and the relationship between seasonality and water quality in four species of Gordiida (Nematomorpha) from Catamarca, Argentina.  

PubMed

A total of 687 adult nematomorphs of four species of Gordiida: Chordodes brasiliensis (393 specimens), Noteochorododes cymatium (47 specimens), N. talensis (162 specimens) and Pseudochordodes dugesi (85 specimens) were collected during a period of 1 year from El Simbolar stream, Argentina. Free-living worms were abundant during autumn and spring, but their number decreased during winter and summer. Males were shorter and significantly more abundant than females. The presence of N. cymatium, N. talensis and P. dugesi was correlated with water temperature and these species were most abundant in winter and spring. The presence of C. brasiliensis was correlated with flow rate and pH; this species was more abundant in autumn and winter. These four species are sympatric. PMID:20932355

Salas, L; De Villalobos, C; Zanca, F

2011-09-01

184

Sexuality and Reproductive Issues (PDQ)  

MedlinePLUS

Sexuality and Reproductive Issues (PDQ®) Sexual Problems as a Side Effect of Cancer Factors Affecting Sexual Function in Cancer Patients Assessing Sexual Function in Cancer Patients Treatment of Sexual Problems in Cancer ...

185

An experimental demonstration of Fisher's principle: evolution of sexual proportion by natural selection.  

PubMed Central

Most sexually reproducing species have sexual proportions around 1:1. This major biological phenomenon remained unexplained until 1930, when FISHER proposed that it results from a mechanism of natural selection. Here we report the first experimental test of his model that obeys all its assumptions. We used a naturally occurring X-Y meiotic drive system--the sex-ratio trait of Drosophila mediopunctat--to generate female-biased experimental populations. As predicted by FISHER, these populations evolved toward equal sex proportions due to natural selection, by accumulation of autosomal alleles that direct the parental reproductive effort toward the rare sex. Classical Fisherian evolution is a rather slow mechanism: despite a very large amount of genetic variability, the experimental populations evolved from 16% of males to 32% of males in 49 generations and would take 330 generations (29 years) to reach 49%. This slowness has important implications for species potentially endangered by skewed sexual proportions, such as reptiles with temperature sex determination. PMID:9504919

Carvalho, A B; Sampaio, M C; Varandas, F R; Klaczko, L B

1998-01-01

186

Population genetic structure of diploid sexual and polyploid apomictic hawthorns (Crataegus; Rosaceae) in the Pacific Northwest.  

PubMed

Polyploidy and gametophytic apomixis are two important and associated processes in plants. Many hawthorn species are polyploids and can reproduce both sexually and apomictically. However, the population genetic structure of these species is poorly understood. Crataegus douglasii is represented exclusively by self-compatible tetraploid pseudogamous apomicts across North America, whereas Crataegus suksdorfii found in the Pacific Northwest is known to include self-incompatible diploid sexuals as well as polyploid apomicts. We compare population structure and genetic variability in these two closely related taxa using microsatellite and chloroplast sequence markers. Using 13 microsatellite loci located on four linkage groups, 251 alleles were detected in 239 individuals sampled from 15 localities. Within-population multilocus genotypic variation and molecular diversity are greatest in diploid sexuals and lowest in triploid apomicts. Apart from the isolation of eastern North American populations of C. douglasii, there is little evidence of isolation by distance in this taxon. Genetic diversity in western populations of C. douglasii suggests that gene flow is frequent, and that colonization and establishment are often successful. In contrast, local populations of C. suksdorfii are more markedly differentiated. Gene flow appears to be limited primarily by distance in diploids and by apomixis and self-compatibility in polyploids. We infer that apomixis and reproductive barriers between cytotypes are factors that reduce the frequency of gene flow among populations, and may ultimately lead to allopatric speciation in C. suksdorfii. Our findings shed light on evolution in woody plants that show heterogeneous ploidy levels and reproductive systems. PMID:19243504

Lo, Eugenia Y Y; Stefanovi?, Sasa; Dickinson, Timothy A

2009-03-01

187

Thoreau's sexuality.  

PubMed

Although Henry David Thoreau (1817-1862) has often been described as lacking in sexual drive or at most a rather reluctant heterosexual, a close study of his life and writings indicates the presence of a pronounced vein of homoeroticism--although there seems to be no concrete evidence of any homosexual activity on his part. Cognizance of that homoeroticism helps one to understand many elements of his life and writings and suggests that his intense love of nature may have resulted from sublimation of that homoeroticism. PMID:1880400

Harding, W

1991-01-01

188

Sexual rights and sexual cultures: reflections on \\  

Microsoft Academic Search

The paper is divided into three sections. The first section focuses on the contested nature of the sexual politics that surrounded the Jacob Zuma rape trial. This sexual politics was not simply the background to the \\

Steven Robins

2006-01-01

189

252 | APRIL 2002 | VOLUME 3 www.nature.com/reviews/genetics also introduces the risk of sexually transmitted diseases  

E-print Network

, such as the infamous twofold cost of sex. In sexual reproduction, the unit of reproduction is the couple, whereas in asexual reproduction it is the individual. Unless the sexually reproducing couple can produce twice reproductive output per capita.At one extreme,if sexual couples and asexual individuals produce the same

Otto, Sarah

190

Sexual Selection on Morphology in an Explosive Breeding Amphibian, the Columbia Spotted Frog (Rana luteiventris)  

Microsoft Academic Search

It is well documented that sexual selection acts on morphological differences between individuals and can lead to sexual dimorphism in species with male combat and female choice. However, the effect of sexual selection on the evolution of morphological traits is poorly understood in species with scramble competition in which males race for access to females during a brief pulse of

Allison E. Greene; W. Chris Funk

2009-01-01

191

Variable sexual ornaments in scarlet-tufted malachite sunbirds ( Nectarinia johnstoni) on Mount Kenya  

Microsoft Academic Search

In order to be elaborated by sexual selection, sexual ornaments must vary perceptibly and genetically among individuals in natural populations. Rather little is known about ornament variation in monogamous species, in which sexual selection should act more weakly than in polygynous species. We report phenotypic variation in feather ornament size (elongated tails and pectoral tufts) and body size in the

Matthew R. Evans; Phoebe Barnard

1995-01-01

192

Lect. 15: Sexual selection Sexual dimorphism  

E-print Network

with reproduction) Selection for sexual dimorphism? · Fitness under natural selection: typically same for both sexes Survival ReproductionFitness Selection for sexual dimorphism? · Must act on sexes differently · Process Fitness Sexual selection · Differential reproductive success due to variation among individuals in ability

193

The Problem... ! Sexual Assault & Sexual Harassment are  

E-print Network

of rape or attempted rape between the age of 14 and 25 ! 9 out of 10 date rapes are not reported ! Women the Terms Sexual Assault #Sexual activity, including but not limited to rape, attempted rape or oral sex, guilt) $ Date rape, a form of sexual assault, is rape by someone the victim is dating. $ Acquaintance

VandeVord, Pamela

194

University of Alberta Sexual Assault Centre Acquaintance Sexual Assault  

E-print Network

University of Alberta Sexual Assault Centre Acquaintance Sexual Assault Sexual assault is any form of sexual contact without voluntary consent, and acquaintance sexual assault is sexual assault where the survivor knows the person who committed the sexual assault. The offending acquaintance may be someone

Machel, Hans

195

Policy on Sexual Harassment Policy on Sexual Harassment  

E-print Network

Policy on Sexual Harassment 09/19/2013 Policy on Sexual Harassment I. Purpose and Scope property. Definitions Sexual Harassment: Unwelcome sexual advances, requests for sexual favors, and other verbal or physical conduct of a sexual nature is sexual harassment when: Submission to such conduct

Sridhar, Srinivas

196

Distribution of Phoxinus eos, Phoxinus neogaeus, and Their Asexually-Reproducing Hybrids (Pisces: Cyprinidae)  

E-print Network

Distribution of Phoxinus eos, Phoxinus neogaeus, and Their Asexually-Reproducing Hybrids (Pisces asexually reproducing vertebrates species. The distribution of hybrid Phoxinus among lakes in Algonquin Park-glacial dispersal, or to differences in ecology. These results suggest that asexual reproduction is a successful

Sokolowski, Marla

197

Species-specific sex pheromones secreted from new sexual glands in two sympatric fungus-growing termites from northern Vietnam, Macrotermes annandalei and M. barneyi  

Microsoft Academic Search

Summary Reproductive isolation in termites is not well known. Our study carried out on two sympatric species from northern Vietnam, Macrotermes annandalei and M. barneyi, showed that dispersal flights and sex pheromones were two important factors in their reproductive isolation. These fungus-growing termites were isolated, partially due to the timing of their respective dispersal flights. M. annandalei flew the first

A. Peppuy; A. Robert; C. Bordereau

2004-01-01

198

Reproduced from: 3 November 2004: B24  

E-print Network

, there is a 50% probability that a gene carried by me is identical to one carried by my sister. This gene, no matter which body it resides in, mine or my sister's, can be transmitted either by me reproducing, or by me "altruistically" doing something that at least doubles the chance my sister will reproduce

Turner, Scott

199

Reproducing Kernel Element Interpolation: Globally Conforming Im  

E-print Network

Reproducing Kernel Element Interpolation: Globally Conforming Im /Cn /P k Hierarchies Shaofan Li1 hierarchies are constructed in the framework of reproducing kernel element method (RKEM) for multi in multiple dimension was the challenge in the early development of finite element methods. It attracted

Li, Shaofan

200

The Sexuality of Childhood Sexual Abuse Survivors  

PubMed Central

In this grounded theory study, a theoretical framework that depicts the process by which childhood sexual abuse (CSA) influences the sexuality of women and men survivors was constructed. Data were drawn from interview transcripts of 95 men and women who experienced CSA. Using constant comparison analysis, the researchers determined that the central phenomenon of the data was a process labeled Determining My Sexual Being, in which survivors moved from grappling with questions related to the nature, cause, and sexual effects of the abuse to laying claim to their own sexuality. Clinical implications are discussed. PMID:21785665

Roller, Cynthia; Martsolf, Donna S; Draucker, Claire Burke; Ross, Ratchneewan

2011-01-01

201

Sexual Problems of Counselees.  

ERIC Educational Resources Information Center

Approximately 50% of American marriages have some sexual dysfunction. Because sexuality is an important part of a person's life, counselors should be sensitive to sexual concerns of their clients. Taking an adequate sex history and highlighting problem areas may increase counseling efficiency. When counselors teach courses on human sexuality, they…

Heritage, Jeannette G.; West, W. Beryl

202

Sexual Risk Factors  

MedlinePLUS

... HIV Translate Text Size Print Lower Your Sexual Risk of HIV How Can I Reduce My Risk Of Getting HIV Through Sexual Contact? In the ... not infected with HIV. Sexual Practices And HIV Risk The risk of getting HIV through sexual contact ...

203

SEXUALITY AND GENDER IDENTITY  

E-print Network

LEARN TO UNDERSTAND SEXUALITY AND GENDER IDENTITY COUNSELLING AND PSYCHOLOGICAL SERVICES CAPS #12;CONTENTS 01 Questioning your sexuality or gender identity 02 Coming out 04 Sexual health 05 Harassment and discrimination 06 Types of support and information available 08 Useful resources Sexual orientation is about who

Viglas, Anastasios

204

Sexual Harassment in Education.  

ERIC Educational Resources Information Center

Three situations of sexual harassment, typical of the complaints received by various departments and offices on all Indiana University campuses, are presented. According to the National Advisory Council on Women's Educational Programs, "academic sexual harassment is the use of authority to emphasize the sexuality or sexual identity of a student in…

Brooks, Nancy A.

1988-01-01

205

Sexuality and Violence.  

ERIC Educational Resources Information Center

The author examines specific manifestations of violence in relation to sexuality: (1) forcible rape rate; (2) war atrocities; (3) sexual violence in prisons; and (4) pornography. Drawing much from Hannah Arendt's book on violence, he views sexual violence as symptomatic of a lack of sexual power, not a sign of its possession. The causes are seen…

Sanctuary, Gerald

206

Addressing Sexual Harassment  

ERIC Educational Resources Information Center

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…

Young, Ellie L.; Ashbaker, Betty Y.

2008-01-01

207

Sexuality and the law.  

PubMed

Federal, state, and local laws in the US now govern almost every aspect of sexuality. This includes sexuality at the workplace, sexuality education, adolescent sexuality, access to sexuality information and sexually explicit materials, sexual orientation, and sexually transmitted disease(STD)/HIV transmission. Almost 33% of the US Supreme Court's docket this past term concerned sexuality issues. In contrast to 50 years ago, when sexuality law was confined to the criminal arena, contemporary "sex crimes" primarily relate to nonconsensual and exploitative behaviors. It is time for lawmakers, judges, lawyers, policy analysts, lobbyists, and advocates to realize they cannot legislate or litigate how, when, or why people fall in love. Rather, the role of the law should be to create and preserve models of justice and equality that seek to preserve one's individual rights to privacy and freedom to choose in matters related to one's sexuality. This includes free access to age-appropriate sexuality information, the right to marriage and children regardless of sexual orientation, comprehensive sexuality education that encompasses information about avoiding unwanted pregnancies and HIV/STDs, access to contraception and abortion, protection from sexually abusive or exploitative relationships, and access to sexual health care. PMID:12295182

Portelli, C J

1998-01-01

208

Sexually transmitted organisms in sexually abused children  

PubMed Central

OBJECTIVE—To establish the prevalence of sexually transmitted organisms and other genital organisms in potentially sexually abused children.?DESIGN—Prospective study of children attending an inner London department of community paediatrics for evaluation of possible sexual abuse.?SUBJECTS—Children under 16 referred for evaluation of possible sexual abuse.?OUTCOME MEASURES—Prevalence of sexually transmitted organisms in relation to age, symptoms, and type of abuse.?RESULTS—Swabs were taken from 159 of 242 girls evaluated. The overall prevalence of sexually transmitted organisms was 3.7%: three girls were infected with gonorrhoea, four with Trichomonas vaginalis, and two with Chlamydia trachomatis. One girl had all three infections plus mycoplasmas. Mycoplasmas were identified in 22% of girls swabbed. Of 30 boys swabbed, none yielded a sexually transmitted organism.?CONCLUSIONS—There is a low prevalence of definitely sexually transmitted organisms in children who might have been abused. Other organisms possibly associated with sexual activity can be identified in this population. Screening for infection should be mandatory in presumed sexually abused girls with vaginal discharge and ideally should be undertaken in all children attending for evaluation of sexual abuse.?? PMID:9875049

Robinson, A; Watkeys, J; Ridgway, G

1998-01-01

209

Sexual selection and mating systems  

PubMed Central

Sexual selection is among the most powerful of all evolutionary forces. It occurs when individuals within one sex secure mates and produce offspring at the expense of other individuals within the same sex. Darwin was first to recognize the power of sexual selection to change male and female phenotypes, and, in noting that sexual selection is nonubiquitous, Darwin was also first to recognize the importance of mating system—the “special circumstances” in which reproduction occurs within species. Analyses of mating systems since Darwin have emphasized either the genetic relationships between male and female mating elements, usually among plants, or the numbers of mates males and females may obtain, usually among animals. Combining these schemes yields a quantitative methodology that emphasizes measurement of the sex difference in the variance in relative fitness, as well as phenotypic and genetic correlations underlying reproductive traits that may arise among breeding pairs. Such information predicts the degree and direction of sexual dimorphism within species, it allows the classification of mating systems using existing genetic and life history data, and with information on the spatial and temporal distributions of fertilizations, it may also predict floral morphology in plants. Because this empirical framework identifies selective forces and genetic architectures responsible for observed male-female differences, it compliments discoveries of nucleotide sequence variation and the expression of quantitative traits. Moreover, because this methodology emphasizes the process of evolutionary change, it is easier to test and interpret than frameworks emphasizing parental investment in offspring and its presumed evolutionary outcomes. PMID:19528645

Shuster, Stephen M.

2009-01-01

210

Sexual arousal, is it for mammals only?  

PubMed Central

Sexual arousal has many dimensions and has consequently been defined in various ways. In humans sexual arousal can be assessed based in part on verbal communication. In male non-human mammalian species it has been argued that arousal can only be definitively inferred if the subject exhibits a penile erection in a sexual context. In non-mammalian species that lack an intromittent organ, as is the case for most avian species, the question of how to assess sexual arousal has not been thoroughly addressed. Based on studies performed in male Japanese quail, we argue that several behavioral or physiological characteristics provide suitable measures of sexual arousal in birds and probably also in other tetrapods. These indices include the performance of appetitive sexual behavior in anticipation of copulation (although anticipation and arousal are not the synonyms), the activation of specific brain areas as identified by the detection of the expression of immediate early genes (fos, egr-1) or by 2-deoxygucose quantitative autoradiography, and above all the release of dopamine in the medial preoptic areas as measured by in vivo dialysis. Based on these criteria, it is possible to assess in birds sexual arousal in its broadest sense but meeting the more restrictive definition of arousal proposed for mammals (erection in an explicit sexual context) is and will probably remain impossible in birds until refinement of in vivo imaging techniques such fMRI allow us to match in different species, with and without an intromittent organ, the brain areas that are activated in the presence of specific stimuli. PMID:21073874

Ball, Gregory F.; Balthazart, Jacques

2012-01-01

211

Regulation of apomixis: learning from sexual experience.  

PubMed

Apomixis is a natural form of asexual reproduction through seeds that leads to viable offspring genetically identical to the mother plant. New evidence from sexual model species indicates that the regulation of female gametogenesis and seed formation is also directed by epigenetic mechanisms that are crucial to control events that distinguish sexuality from apomixis, with important implications for our understanding of the evolutionary forces that shape structural variation and diversity in plant reproduction. PMID:23000434

Rodriguez-Leal, Daniel; Vielle-Calzada, Jean-Philippe

2012-11-01

212

Numerical reproducibility for implicit Monte Carlo simulations  

SciTech Connect

We describe and compare different approaches for achieving numerical reproducibility in photon Monte Carlo simulations. Reproducibility is desirable for code verification, testing, and debugging. Parallelism creates a unique problem for achieving reproducibility in Monte Carlo simulations because it changes the order in which values are summed. This is a numerical problem because double precision arithmetic is not associative. In [1], a way of eliminating this roundoff error using integer tallies was described. This approach successfully achieves reproducibility at the cost of lost accuracy by rounding double precision numbers to fewer significant digits. This integer approach, and other extended reproducibility techniques, are described and compared in this work. Increased precision alone is not enough to ensure reproducibility of photon Monte Carlo simulations. A non-arbitrary precision approaches required a varying degree of rounding to achieve reproducibility. For the problems investigated in this work double precision global accuracy was achievable by using 100 bits of precision or greater on all unordered sums which where subsequently rounded to double precision at the end of every time-step. (authors)

Cleveland, M.; Brunner, T.; Gentile, N. [Lawrence Livermore National Laboratory, P. O. Box 808, Livermore CA 94550 (United States)

2013-07-01

213

Sexual compatibility and the sexual desire-motivation relation in females with hypoactive sexual desire disorder.  

PubMed

Fifty-four female participants with hypoactive sexual desire disorder supplied daily reports of their sexual desire and motivation. The relation between desire and motivation remained statistically significant when controlling for sexual compatibility, sexual stress, sexual fantasy, and marital and sexual satisfaction. Findings suggest that (a) women higher in sexual compatibility experience greater sexual motivation regardless of their marital and sexual satisfaction, their sexual desire intensity, and depressive symptomatology; and (b) the relation between sexual compatibility and sexual desire is mediated by the propensity of those women high in sexual compatibility to have greater marital and sexual satisfaction. Within-subject analyses that controlled for autocorrelation and linear trends in the time series revealed that 40% of the women experienced significantly higher sexual motivation on greater sexual desire days. A discussion of these findings and evidence for the addition of sexual motivation as a distinct phase in the human sexual response cycle are explored. PMID:10881380

Hurlbert, D F; Apt, C; Hurlbert, M K; Pierce, A P

2000-07-01

214

Sexual selection and natural selection in bird speciation  

PubMed Central

The role of sexual selection in speciation is investigated, addressing two main issues. First, how do sexually selected traits become species recognition traits? Theory and empirical evidence suggest that female preferences often do not evolve as a correlated response to evolution of male traits. This implies that, contrary to runaway (Fisherian) models of sexual selection, premating isolation will not arise as an automatic side effect of divergence between populations in sexually selected traits. I evaluate premating isolating mechanisms in one group, the birds. In this group premating isolation is often a consequence of sexual imprinting, whereby young birds learn features of their parents and use these features in mate choice. Song, morphology and plumage are known recognition cues. I conclude that perhaps the main role for sexual selection in speciation is in generating differences between populations in traits. Sexual imprinting then leads to these traits being used as species recognition mechanisms. The second issue addressed in this paper is the role of sexual selection in adaptive radiation, again concentrating on birds. Ecological differences between species include large differences in size, which may in themselves be sufficient for species recognition, and differences in habitat, which seem to evolve frequently and at all stages of an adaptive radiation. Differences in habitat often cause song and plumage patterns to evolve as a result of sexual selection for efficient communication. Therefore sexual selection is likely to have an important role in generating premating isolating mechanisms throughout an adaptive radiation. It is also possible that sexual selection, by creating more allopatric species, creates more opportunity for ecological divergence to occur. The limited available evidence does not support this idea. A role for sexual selection in accelerating ecological diversification has yet to be demonstrated.

Price, T.

1998-01-01

215

Statistics of sexual size dimorphism  

Microsoft Academic Search

In comparative studies of sexual size dimorphism (SSD), the methods used to quantify dimorphism are controversial. SSD is commonly expressed as a ratio between species mean values of males and females, such as M\\/F or (M?F)\\/([M+F]\\/2), but a number of investigators have suggested that ratios should not be used, mainly because their distributions usually violate the assumptions of parametric statistical

Richard J. Smith

1999-01-01

216

Endocrine regulation and sexual differentiation of avian copulatory sexually selected characters.  

PubMed

Reproductive specializations in birds have provided intriguing model systems to better understand the role of endocrine mechanisms that regulate phenotype expression and the action of sexual selection. A comparative approach can elucidate how endocrine systems associated with control of sexual differentiation, sexual maturation, and reproductive physiology and behavior have diversified. Here we compare the copulatory sexually selected traits of two members of the galloanseriform superfamily: quail and ducks. Japanese quail have a non-intromittent penis, and they have evolved a unique foam gland that is known to be involved in post-copulatory sexual selection. In contrast, ducks have maintained a large intromittent penis that has evolved via copulatory male-male competition and has been elaborated in a sexually antagonistic race due to sexual conflict with females over mating. These adaptations function in concert with sex-specific and, in part, species-specific behaviors. Although the approaches to study these traits have been different, exploring the differences in neuroendocrine regulation of sexual behavior, development and seasonality of the foam gland and the penis side by side, allow us to suggest some areas where future research would be productive to better understand the evolution of novelty in sexually selected traits. PMID:25179524

Brennan, Patricia L R; Adkins-Regan, Elizabeth

2014-10-01

217

Sexual narcissism and the perpetration of sexual aggression.  

PubMed

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

Widman, Laura; McNulty, James K

2010-08-01

218

Sexual selection and the risk of extinction in birds.  

PubMed Central

The relationship between sexual selection and extinction risk has rarely been investigated. This is unfortunate because extinction plays a key role in determining the patterns of species richness seen in extant clades, which form the basis of comparative studies into the role that sexual selection may play in promoting speciation. We investigate the extent to which the perceived risk of extinction relates to four different estimates of sexual selection in 1030 species of birds. We find no evidence that the number of threatened species is distributed unevenly according to a social mating system, and neither of our two measures of pre-mating sexual selection (sexual dimorphism and dichromatism) was related to extinction risk, after controlling for phylogenetic inertia. However, threatened species apparently experience more intense post-mating sexual selection, measured as testis size, than non-threatened species. These results persisted after including body size as a covariate in the analysis, and became even stronger after controlling for clutch size (two known correlates of extinction risk). Sexual selection may therefore be a double-edged process-promoting speciation on one hand but promoting extinction on the other. Furthermore, we suggest that it is post-mating sexual selection, in particular, that is responsible for the negative effect of sexual selection on clade size. Why this might be is unclear, but the mean population fitness of species with high intensities of post-mating sexual selection may be especially low if costs associated with multiple mating are high or if the selection load imposed by post-mating selection is higher relative to that of pre-mating sexual selection. PMID:12964981

Morrow, Edward H; Pitcher, Trevor E

2003-01-01

219

Copyright Association for Investment Management Research. Reproduced  

E-print Network

Copyright Association for Investment Management Research. Reproduced republished Benchmarks Attribution permission Association for Investment Management All ©2001, ® www.aimr.org . Toward Agent of money relationships imply. is about demands investors create inefficiencies. inefficiencies arise

220

Reproducibility of neuroendocrine lung tumor classification  

Microsoft Academic Search

For a tumor classification scheme to be useful, it must be reproducible and it must show clinical significance. Classification of neuroendocrine lung tumors is a difficult problem with little information about interobserver reproducibility. We sought to evaluate the classification of typical carcinoid (TC), atypical carcinoid (AC), large-cell neuroendocrine carcinoma (LCNEC), and small-cell carcinoma (SCC) tumors as proposed by W.D. Travis

William D Travis; Anthony A Gal; Thomas V Colby; David S Klimstra; Roni Falk; Michael N Koss

1998-01-01

221

Optimal seeding of self-reproducing systems.  

PubMed

This article is motivated by the need to minimize the number of elements required to establish a self-reproducing system. One such system is a self-reproducing extraterrestrial robotic colony, which reduces the launch payload mass for space exploration compared to current mission configurations. In this work, self-reproduction is achieved by the actions of a robot on available resources. An important consideration for the establishment of any self-reproducing system is the identification of a seed, for instance, a set of resources and a set of robots that utilize them to produce all of the robots in the colony. This article outlines a novel algorithm to determine an optimal seed for self-reproducing systems, with application to a self-reproducing extraterrestrial robotic colony. Optimality is understood as the minimization of a cost function of the resources and, in this article, the robots. Since artificial self-reproduction is currently an open problem, the algorithm is illustrated with a simple robotic self-replicating system from the literature and with a more complicated self-reproducing example from nature. PMID:22035080

Menezes, Amor A; Kabamba, Pierre T

2012-01-01

222

Indian concepts on sexuality  

PubMed Central

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. PMID:23858263

Chakraborty, Kaustav; Thakurata, Rajarshi Guha

2013-01-01

223

Indian concepts on sexuality.  

PubMed

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. PMID:23858263

Chakraborty, Kaustav; Thakurata, Rajarshi Guha

2013-01-01

224

Hormones and History: The Evolution and Development of Primate Female Sexuality  

PubMed Central

Sexual behavior is required for reproduction in internally fertilizing species but poses significant social and physical risks. Females in many nonprimate species have evolved physical and behavioral mechanisms restricting sexual behavior to when females are fertile. The same hormones producing female fertility also control these mechanisms, assuring that sex only occurs when reproduction is possible. In contrast to nonprimate mammals, hormones do not regulate the capacity to engage in sex in female anthropoid primates, uncoupling fertility and the physical capacity to mate. Instead, in primates, sexual motivation has become the primary coordinator between sexual behavior and fertility. This dependence upon psychological mechanisms to coordinate physiology with behavior is possibly unique to primates, including humans, and allows a variety of nonphysiological influences, particularly social context, to regulate sexual behavior. The independence between hormonal state and sexual behavior allows sex to be used for social purposes. This complex regulation of primate sexuality develops during adolescence, where female monkeys show both hormonally influenced sexual motivation and socially modulated sexual behavior. We present findings from rhesus monkeys illustrating how social context and hormonal state interact to modulate adolescent and adult sexuality. It is argued that this flexibility in sexual behavior, combined with a tight regulation of sexual motivational systems by reproductive hormones, allows sexual behavior to be used for nonreproductive purposes while still assuring its occurrence during periods of female fertility. The evolutionary pressures that produced such flexibility in sexual behavior remain puzzling, but may reflect the importance of sexuality to primate social attraction and cohesion. PMID:15216429

Wallen, Kim; Zehr, Julia L.

2005-01-01

225

Peering through the looking glass at a sexual parasite: are Amazon mollies red queens?  

PubMed

The gynogenetic Amazon molly (Poecilia formosa) is a clonal, all-female lineage of livebearing fish that faces an unusual obstacle to evolutionary persistence. Sperm from heterospecific males (either sailfin, P. latipinna, or Atlantic, P. mexicana, mollies) is necessary to trigger embryogenesis. However, none of the male's genes are incorporated into the genome of the gynogenetic offspring. Some investigators have proposed that the evolution of male mate discrimination is a result of this cost, leading to a coevolutionary arms race between male avoidance of P. formosa and P. formosa attractiveness. Given that P. formosa successfully reproduces and has not yet gone extinct, it is clear there are mechanisms by which they attract the sexual attention of males. Although a Red Queen coevolutionary process in typical host/parasite systems has been shown to favor the persistence of sexual species, in this system an arms race has been invoked to explain the reverse. Here I present behavioral data supporting a more parsimonious scenario: that mechanisms of attraction in P. formosa are simply a consequence of its hybrid origin. Poecilia latipinna and P. mexicana males do not discriminate between gynogenetic P. formosa females and first generation sexual hybrid females, and females do not differ in agonistic behaviors associated with competition for mates. Both results contradict predictions from the Red Queen hypothesis. Therefore, coevolution is not necessary to explain the apparent evolutionary persistence of P. formosa. PMID:12894946

Dries, Laurie A

2003-06-01

226

Causes of sexual dysfunction (image)  

MedlinePLUS

Female sexual dysfunction describes women who are indifferent or hostile to sexual intercourse, who have no response to sexual advances or stimulation, or who are unable to have an orgasm during sexual intercourse.

227

Reproductive Strategies Sexual vs. asexual  

E-print Network

Reproductive Strategies Sexual vs. asexual Selfing vs. outcrossing #12;Sexual vs. Asexual Sexual the metapopulation. Propagule loss (predators, inappropriate sites). #12;Sexual vs. Asexual Asexual reproduction reproduction. Recombination. Reduces genetic load. Breaks up adaptive gene combinations. Economics. Cost

Cruzan, Mitchell B.

228

Tell Someone Responding to sexual harassment and sexual violence  

E-print Network

1 of 5 Tell Someone Responding to sexual harassment and sexual violence in the School of Engineering and Applied Sciences (SEAS) What is sexual harassment? Harvard University has adopted the following definition of sexual harassment: Sexual harassment is any unwelcome conduct of a sexual nature

Loncar, Marko

229

University of California Policy Sexual Harassment and Sexual Violence  

E-print Network

#12;University of California Policy Sexual Harassment and Sexual Violence 1 of 20 Academic Student prohibits sexual harassment and sexual violence, and that such behavior violates both law and University policy. The University will respond promptly and effectively to reports of sexual harassment and sexual

Jacobs, Lucia

230

Experimental evolution of a novel sexually antagonistic allele.  

PubMed

Evolutionary conflict permeates biological systems. In sexually reproducing organisms, sex-specific optima mean that the same allele can have sexually antagonistic expression, i.e. beneficial in one sex and detrimental in the other, a phenomenon known as intralocus sexual conflict. Intralocus sexual conflict is emerging as a potentially fundamental factor for the genetic architecture of fitness, with important consequences for evolutionary processes. However, no study to date has directly experimentally tested the evolutionary fate of a sexually antagonistic allele. Using genetic constructs to manipulate female fecundity and male mating success, we engineered a novel sexually antagonistic allele (SAA) in Drosophila melanogaster. The SAA is nearly twice as costly to females as it is beneficial to males, but the harmful effects to females are recessive and X-linked, and thus are rarely expressed when SAA occurs at low frequency. We experimentally show how the evolutionary dynamics of the novel SAA are qualitatively consistent with the predictions of population genetic models: SAA frequency decreases when common, but increases when rare, converging toward an equilibrium frequency of ?8%. Furthermore, we show that persistence of the SAA requires the mating advantage it provides to males: the SAA frequency declines towards extinction when the male advantage is experimentally abolished. Our results empirically demonstrate the dynamics underlying the evolutionary fate of a sexually antagonistic allele, validating a central assumption of intralocus sexual conflict theory: that variation in fitness-related traits within populations can be maintained via sex-linked sexually antagonistic loci. PMID:22956914

Dean, Rebecca; Perry, Jennifer C; Pizzari, Tommaso; Mank, Judith E; Wigby, Stuart

2012-01-01

231

Molecular cloning and sexually dimorphic expression of DM-domain genes in Daphnia magna  

Microsoft Academic Search

Daphnia magna is known to switch between sexual and asexual reproduction depending on the environment. It reproduces asexually when in an optimal environment for food, photoperiod, and population density. Once the environment declines, it changes reproductive strategy from asexual to sexual reproduction. However, the molecular bases of environmental sex determination are largely unknown. To understand the molecular mechanisms of environmental

Yasuhiko Kato; Kaoru Kobayashi; Shigeto Oda; John K. Colbourn; Norihisa Tatarazako; Hajime Watanabe; Taisen Iguchi

2008-01-01

232

An Overview of Sexual Harassment  

ERIC Educational Resources Information Center

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.…

Stier, William F., Jr.

2005-01-01

233

A Reproducible Oral Microcosm Biofilm Model for Testing Dental Materials  

PubMed Central

Aims Most studies of biofilm effects on dental materials use single-species biofilms, or consortia. Microcosm biofilms grown directly from saliva or plaque are much more diverse, but difficult to characterize. We used the Human Oral Microbial Identification Microarray (HOMIM) to validate a reproducible oral microcosm model. Methods and Results Saliva and dental plaque were collected from adults and children. Hydroxyapatite and dental composite disks were inoculated with either saliva or plaque, and microcosm biofilms were grown in a CDC biofilm reactor. In later experiments, the reactor was pulsed with sucrose. DNA from inoculums and microcosms were analyzed by HOMIM for 272 species. Microcosms included about 60% of species from the original inoculum. Biofilms grown on hydroxyapatite and composites were extremely similar. Sucrose-pulsing decreased diversity and pH, but increased the abundance of Streptococcus and Veilonella. Biofilms from the same donor, grown at different times, clustered together. Conclusions This model produced reproducible microcosm biofilms that were representative of the oral microbiota. Sucrose induced changes associated with dental caries. Significance and Impact of the Study This is the first use of HOMIM to validate an oral microcosm model that can be used to study the effects of complex biofilms on dental materials. PMID:22925110

Rudney, J.D.; Chen, R.; Lenton, P.; Li, J.; Li, Y.; Jones, R.S.; Reilly, C.; Fok, A.S.; Aparicio, C.

2012-01-01

234

Ethnicity and sexuality  

E-print Network

for understanding ethnic relations, I review constructionist models of ethnicity and sexuality in the social sciences and humanities, and I discuss ethnosexual boundary processes in several historical and contemporary settings: the sexual policing of nationalism...

Nagel, Joane

2000-01-01

235

Military Sexual Trauma  

MedlinePLUS

... or with implied better treatment in exchange for sex), may have been unable to consent to sexual activities (for example, when intoxicated), or may have been physically forced into sexual activities. Other experiences that fall into ...

236

FAQ: Child Sexual Exploitation  

MedlinePLUS

... Law Enforcement Training Victim & Family Support FAQ: Child Sexual Exploitation What is child pornography? Federal law (18 ... in graphic bestiality, sadistic or masochistic abuse or sexual intercourse, including genital-genital, oral-genital, anal-genital ...

237

Female Sexual Dysfunction  

MedlinePLUS

What is female sexual dysfunction (FSD)? Many women have a low sex drive or trouble having an orgasm. Some women are not bothered ... this, but others are. A woman has female sexual dysfunction, also called FSD, when she is upset ...

238

Sexual Problems in Men  

MedlinePLUS

Many men have sexual problems. They become more common as men age. Problems can include Erectile dysfunction Reduced or lost interest in sex ... problems may also be factors. Occasional problems with sexual function are common. If problems last more than ...

239

Child Sexual Abuse  

MedlinePLUS

... print a PDF version of this document . Child sexual abuse has been reported up to 80,000 ... professional help . The long-term emotional damage of sexual abuse can be devastating to the child. Child ...

240

Sexuality in Older Adults  

MedlinePLUS

... feel good about yourself. As you age, your sexual health will change. But growing older doesn’t have ... life at any age. How does aging affect sexual health? Changes for women: As a woman approaches menopause, ...

241

Sexual Problems in Women  

MedlinePLUS

... results from past sexual trauma. Occasional problems with sexual function are common. If problems last more than a few months or cause distress for you or your partner, you should see your health care provider.

242

Understanding Sexual Violence  

MedlinePLUS

... engage in risky sexual activity. Why is sexual violence a public health problem? SV is a significant problem in the United States: • Among high school students surveyed nationwide, about 8% reported having been ...

243

Responding to Sexual Assault  

E-print Network

University will not tolerate sexual assault in any form, including acquaintance rape. Where there is probable assault, we think of rape. However, rape is not the only type of sexual assault. These words can be used

Ravikumar, B.

244

Reproducibility responsibilities in the HPC arena  

SciTech Connect

Expecting bit-for-bit reproducibility in the HPC arena is not feasible because of the ever changing hardware and software. No user s application is an island; it lives in an HPC eco-system that changes over time. Old hardware stops working and even old software won t run on new hardware. Further, software libraries change over time either by changing the internals or even interfaces. So bit-for-bit reproducibility should not be expected. Rather a reasonable expectation is that results are reproducible within error bounds; or that the answers are close (which is its own debate.) To expect a researcher to reproduce their own results or the results of others within some error bounds, there must be enough information to recreate all the details of the experiment. This requires complete documentation of all phases of the researcher s workflow; from code to versioning to programming and runtime environments to publishing of data. This argument is the core statement of the Yale 2009 Declaration on Reproducible Research [1]. Although the HPC ecosystem is often outside the researchers control, the application code could be built almost identically and there is a chance for very similar results with just only round-off error differences. To achieve complete documentation at every step, the researcher, the computing center, and the funding agencies all have a role. In this thesis, the role of the researcher is expanded upon as compared to the Yale report and the role of the computing centers is described.

Fahey, Mark R [ORNL; McLay, Robert [Texas Advanced Computing Center

2014-01-01

245

Relevance relations for the concept of reproducibility  

PubMed Central

The concept of reproducibility is widely considered a cornerstone of scientific methodology. However, recent problems with the reproducibility of empirical results in large-scale systems and in biomedical research have cast doubts on its universal and rigid applicability beyond the so-called basic sciences. Reproducibility is a particularly difficult issue in interdisciplinary work where the results to be reproduced typically refer to different levels of description of the system considered. In such cases, it is mandatory to distinguish between more and less relevant features, attributes or observables of the system, depending on the level at which they are described. For this reason, we propose a scheme for a general ‘relation of relevance’ between the level of complexity at which a system is considered and the granularity of its description. This relation implies relevance criteria for particular selected aspects of a system and its description, which can be operationally implemented by an interlevel relation called ‘contextual emergence’. It yields a formally sound and empirically applicable procedure to translate between descriptive levels and thus construct level-specific criteria for reproducibility in an overall consistent fashion. Relevance relations merged with contextual emergence challenge the old idea of one fundamental ontology from which everything else derives. At the same time, our proposal is specific enough to resist the backlash into a relativist patchwork of unconnected model fragments. PMID:24554574

Atmanspacher, H.; Bezzola Lambert, L.; Folkers, G.; Schubiger, P. A.

2014-01-01

246

Parasitism and the expression of sexual dimorphism.  

PubMed

Although a negative covariance between parasite load and sexually selected trait expression is a requirement of few sexual selection models, such a covariance may be a general result of life-history allocation trade-offs. If both allocation to sexually selected traits and to somatic maintenance (immunocompetence) are condition dependent, then in populations where individuals vary in condition, a positive covariance between trait expression and immunocompetence, and thus a negative covariance between trait and parasite load, is expected. We test the prediction that parasite load is generally related to the expression of sexual dimorphism across two breeding seasons in a wild salamander population and show that males have higher trematode parasite loads for their body size than females and that a key sexually selected trait covaries negatively with parasite load in males. We found evidence of a weaker negative relationship between the analogous female trait and parasite infection. These results underscore that parasite infection may covary with expression of sexually selected traits, both within and among species, regardless of the model of sexual selection, and also suggest that the evolution of condition dependence in males may affect the evolution of female trait expression. PMID:25750721

De Lisle, Stephen P; Rowe, Locke

2015-02-01

247

Hypoactive Sexual Desire Disorder  

Microsoft Academic Search

\\u000a Hypoactive Sexual Desire Disorder (HSDD) is diagnosed when an individual indicates persistent or recurrent blunted levels\\u000a of sexual desire and\\/or a lack of sexual fantasies that cause marked distress and\\/or interpersonal difficulties [1]. This\\u000a diagnosis is intended to include only individuals who experience dissatisfaction with their low levels of sexual desire. Women\\u000a with this condition will often report that they

Alessandra H. Rellini; Melissa A. Farmer; Gale H. Golden

248

Schooling & Sexualities: Teaching for a Positive Sexuality.  

ERIC Educational Resources Information Center

This collection of papers contains a Foreword by Jane Kenway, an Introduction by Louise Laskey and Catherine Beavis, and four sections. Section 1, Schools and the Social Construction of Sexuality, contains 3 chapters: (1) Power and Partnership? Challenging the Sexual Construction of Schooling (D. Denborough); (2) Where Do You Draw the Line?…

Laskey, Louise, Ed.; Beavis, Catherine, Ed.

249

Sexual Differentiation of the Vertebrate Brain: Principles and Mechanisms  

E-print Network

Sexual Differentiation of the Vertebrate Brain: Principles and Mechanisms Bradley Cooke, Carol D the sexes, have been described in the brains of many vertebrate species, including humans. In animal models of neural sexual dimorphism, gonadal steroid hormones, specifically androgens, play a crucial role

Breedlove, Marc

250

Sexual Differentiation of the Vertebrate Brain: Principles and Mechanisms  

Microsoft Academic Search

A wide variety of sexual dimorphisms, structural differences between the sexes, have been described in the brains of many vertebrate species, including humans. In animal models of neural sexual dimorphism, gonadal steroid hormones, specifically androgens, play a crucial role in engendering these differences by masculinizing the nervous system of males. Usually, the androgen must act early in life, often during

Bradley Cooke; Carol D. Hegstrom; Loic S. Villeneuve; S. Marc Breedlove

1998-01-01

251

Sexual selection and the risk of extinction in birds  

Microsoft Academic Search

The relationship between sexual selection and extinction risk has rarely been investigated. This is unfortu- nate because extinction plays a key role in determining the patterns of species richness seen in extant clades, which form the basis of comparative studies into the role that sexual selection may play in promot- ing speciation. We investigate the extent to which the perceived

Edward H. Morrow; Trevor E. Pitcher

2003-01-01

252

Loneliness and Sexual Dysfunctions.  

ERIC Educational Resources Information Center

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…

Mijuskovic, Ben

1987-01-01

253

Sexuality Sensitive Schooling  

Microsoft Academic Search

American schools, especially their physical education and sport programs, provide some of the most hostile social geographies in all of society for gay youth. With the aim of transforming schools toward more democratic and sexuality sensitive institutions, this paper reviews the literature on sexuality and education. In the review, three themes, critical for educators pursuing sexuality sensitive change in schools,

Nate McCaughtry; Suzanna Rocco Dillon; Elizabeth Jones; Sara Smigell

2005-01-01

254

Sexuality in multiple sclerosis  

Microsoft Academic Search

Summary. Sexuality and partnership have an important influence on the quality of life of every person and also on people with chronic disorders such as multiple sclerosis. The findings in literature show high evidence that people with multiple sclerosis experience high levels of sexual dysfunction, most of them with hypoactive sexual behaviour often associated with dissatisfaction in relationship, and also

E. Z. Schmidt; P. Hofmann; G. Niederwieser; H.-P. Kapfhammer; R. M. Bonelli

2005-01-01

255

Sexuality: A Human Condition  

ERIC Educational Resources Information Center

Rehabilitation has too long ignored a vital concern for those who are disabled--their sexuality. The author describes the scope of the problem of sexual function in disability and its validity as a rehabilitation issue. Also explored is the rehabilitation professional's role in facilitating the client's sexual development. (Author/EA)

Berkman, Anne H.

1975-01-01

256

Sexual Harassment in Education.  

ERIC Educational Resources Information Center

In a recent BEST (Bureau of Evaluative Studies and Testing, Indiana University, Bloomington) survey, 10 percent of Indiana University women who responded had experienced some form of sexual harassment. Sexual harassment in education is any attention of a sexual nature from an instructor or professor which makes a student uncomfortable in class or…

Campbell, D'Ann

1986-01-01

257

Pathfinder Series Sexual Harassment  

E-print Network

Pathfinder Series Sexual Harassment Online Periodical Indexes (httpInfo Periodical Articles Byrne, John A. "Sexual Harassment at McKinsey?" Business Week 3505 (Dec. 9, 1996 in Worker's Attitudes Toward Sexual Harassment." Journal of Psychology 130:6 (Nov. 1996):627- . (BF1 .J67

Kearfott, R. Baker

258

Sexual fantasies and sexual arousal in women with a history of childhood sexual abuse  

Microsoft Academic Search

Treatments of female sexual arousal dysfunction for childhood sexual abuse (CSA) survivors could greatly benefit from more information on mechanisms to the sexual arousal problems specific to this population. In this study, 60 CSA survivors and 120 women with no history of CSA (NCSA) participated in an Internet-based survey on sexual arousal and sexual fantasies. Self-reported sexual arousal was measured

Julia Camuso; Alessandra H. Rellini

2010-01-01

259

ORIGINAL PAPER Sexual Self-Schemas, Sexual Dysfunction, and the Sexual Responses  

E-print Network

ORIGINAL PAPER Sexual Self-Schemas, Sexual Dysfunction, and the Sexual Responses of Women with a History of Childhood Sexual Abuse Alessandra H. Rellini · Cindy M. Meston Received: 30 June 2009 / Revised to the mediating effects of sexual self-schemas on the sexual difficulties of women with a history of childhood

Meston, Cindy

260

WHY DO MOST TROPICAL ANIMALS REPRODUCE SEASONALLY? TESTING HYPOTHESES ON AN AUSTRALIAN SNAKE  

Microsoft Academic Search

Most species reproduce seasonally, even in the tropics where activity occurs year-round. Squamate reptiles provide ideal model organisms to clarify the ultimate (adap- tive) reasons for the restriction of reproduction to specific times of year. Females of almost all temperate-zone reptile species produce their eggs or offspring in the warmest time of the year, thereby synchronizing embryogenesis with high ambient

G. P. Brown; R. Shine

2006-01-01

261

Discovery of a Sexual Cycle in Aspergillus lentulus, a Close Relative of A. fumigatus  

PubMed Central

Aspergillus lentulus was described in 2005 as a new species within the A. fumigatus sensu lato complex. It is an opportunistic human pathogen causing invasive aspergillosis with high mortality rates, and it has been isolated from clinical and environmental sources. The species is morphologically nearly identical to A. fumigatus sensu stricto, and this similarity has resulted in their frequent misidentification. Comparative studies show that A. lentulus has some distinguishing growth features and decreased in vitro susceptibility to several antifungal agents, including amphotericin B and caspofungin. Similar to the once-presumed-asexual A. fumigatus, it has only been known to reproduce mitotically. However, we now show that A. lentulus has a heterothallic sexual breeding system. A PCR-based mating-type diagnostic detected isolates of either the MAT1-1 or MAT1-2 genotype, and examination of 26 worldwide clinical and environmental isolates revealed similar ratios of the two mating types (38% versus 62%, respectively). MAT1-1 and MAT1-2 idiomorph regions were analyzed, revealing the presence of characteristic alpha and high-mobility-group (HMG) domain genes, together with other more unusual features such as a MAT1-2-4 gene. We then demonstrated that A. lentulus possesses a functional sexual cycle with mature cleistothecia, containing heat-resistant ascospores, being produced after 3 weeks of incubation. Recombination was confirmed using molecular markers. However, isolates of A. lentulus failed to cross with highly fertile strains of A. fumigatus, demonstrating reproductive isolation between these sibling species. The discovery of the A. lentulus sexual stage has significant implications for the management of drug resistance and control of invasive aspergillosis associated with this emerging fungal pathogen. PMID:23650087

Swilaiman, Sameira S.; O'Gorman, Céline M.; Balajee, S. Arunmozhi

2013-01-01

262

Natural and sexual selection against hybrid flycatchers  

PubMed Central

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 species-specific molecular markers from collared (Ficedula albicollis) and pied (Ficedula hypoleuca) flycatchers and their hybrids, we were able to quantify all key components of fitness. To disentangle the relative role of natural and sexual selection acting on F1 hybrid flycatchers, we estimated various fitness components, which when combined represent the total lifetime reproductive success of F1 hybrids, and then compared the different fitness components of F1 hybrids to that of collared flycatchers. Female hybrid flycatchers are sterile, with natural selection being the selective force involved, but male hybrids mainly experienced a reduction in fitness through sexual selection (decreased pairing success and increased rate of being cuckolded). To disentangle the role of sexual selection against male hybrids from a possible effect of genetic incompatibility (on the rate of being cuckolded), we compared male hybrids with pure-bred males expressing intermediate plumage characters. Given that sexual selection against male hybrids is a result of their intermediate plumage, we expect these two groups of males to have a similar fitness reduction. Alternatively, hybrids have reduced fitness owing to genetic incompatibility, in which case their fitness should be lower than that of the intermediate pure-bred males. We conclude that sexual selection against male hybrids accounts for approximately 75% of the reduction in their fitness. We discuss how natural and sexual selection against hybrids may have different implications for speciation and conclude that reinforcement of reproductive barriers may be more likely when there is sexual selection against hybrids. PMID:18211878

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

2008-01-01

263

The Sexually Dimorphic Medial Preoptic Nucleus of Quail: A Key Brain Area Mediating Steroid Action on Male Sexual Behavior  

Microsoft Academic Search

About 10 years ago, a sexually differentiated nucleus was identified in the preoptic area (POA) of the Japanese quail in the course of studies analyzing the dimorphic mechanisms involved in the activation of sexual behavior. In this species, males exposed to testosterone copulate while females never show this masculine behavior. The present paper reviews anatomical, neurochemical, and functional data that

Gian Carlo Panzica; Carla Viglietti-Panzica; Jacques Balthazart

1996-01-01

264

Sexual differentiation in three unconventional mammals: Spotted hyenas, elephants and tammar wallabies  

Microsoft Academic Search

The present review explores sexual differentiation in three non-conventional species: the spotted hyena, the elephant and the tammar wallaby, selected because of the natural challenges they present for contemporary understanding of sexual differentiation. According to the prevailing view of mammalian sexual differentiation, originally proposed by Alfred Jost, secretion of androgen and anti-Mullerian hormone (AMH) by the fetal testes during critical

Stephen E. Glickman; Roger V. Short; Marilyn B. Renfree

2005-01-01

265

Effects of clonality on the genetic variability of rare, insular species: the case of Ruta microcarpa from the Canary Islands  

PubMed Central

Many plant species combine sexual and clonal reproduction. Clonal propagation has ecological costs mainly related to inbreeding depression and pollen discounting; at the same time, species able to reproduce clonally have ecological and evolutionary advantages being able to persist when conditions are not favorable for sexual reproduction. The presence of clonality has profound consequences on the genetic structure of populations, especially when it represents the predominant reproductive strategy in a population. Theoretical studies suggest that high rate of clonal propagation should increase the effective number of alleles and heterozygosity in a population, while an opposite effect is expected on genetic differentiation among populations and on genotypic diversity. In this study, we ask how clonal propagation affects the genetic diversity of rare insular species, which are often characterized by low levels of genetic diversity, hence at risk of extinction. We used eight polymorphic microsatellite markers to study the genetic structure of the critically endangered insular endemic Ruta microcarpa. We found that clonality appears to positively affect the genetic diversity of R. microcarpa by increasing allelic diversity, polymorphism, and heterozygosity. Moreover, clonal propagation seems to be a more successful reproductive strategy in small, isolated population subjected to environmental stress. Our results suggest that clonal propagation may benefit rare species. However, the advantage of clonal growth may be only short-lived for prolonged clonal growth could ultimately lead to monoclonal populations. Some degree of sexual reproduction may be needed in a predominantly clonal species to ensure long-term viability. PMID:23789068

Meloni, M; Reid, A; Caujapé-Castells, J; Marrero, Á; Fernández-Palacios, J M; Mesa-Coelo, R A; Conti, E

2013-01-01

266

PsMPK7, a stress-associated mitogen-activated protein kinase (MAPK) in Phytophthora sojae, is required for stress tolerance, reactive oxygenated species detoxification, cyst germination, sexual reproduction and infection of soybean.  

PubMed

The sensing of stress signals and their transduction into appropriate responses are crucial for the adaptation, survival and infection of phytopathogenic fungi and oomycetes. Amongst evolutionarily conserved pathways, mitogen-activated protein kinase (MAPK) cascades function as key signal transducers that use phosphorylation to convey information. In this study, we identified a gene, designated PsMPK7, one of 14 predicted genes encoding MAPKs in Phytophthora sojae. PsMPK7 was highly transcribed in each tested stage, but was up-regulated in the zoospore, cyst and cyst germination stages. Silencing of PsMPK7 affected the growth of germinated cysts, oospore production and the pathogenicity of soybean. PsMPK7 transcription was induced by stresses from sorbitol, NaCl and hydrogen peroxide. Transformants in which PsMPK7 expression was silenced (PsMPK7-silenced) were significantly more sensitive to osmotic and oxidative stress. Aniline blue and diaminobenzidine staining revealed that the silenced lines did not suppress the host reactive oxygen species (ROS) burst, indicating that either the inoculated plants activated stronger defence responses to the transformants and/or the PsMPK7-silenced transformants failed to overcome plant defences. In addition, extracellular secretion of laccase decreased in the silenced lines. Overall, our results indicate that the PsMPK7 gene encodes a stress-associated MAPK in P.?sojae that is important not only for responses to various stresses, but also for ROS detoxification, cyst germination, sexual oospore production and infection of soybean. PMID:24889742

Gao, Jian; Cao, Mingna; Ye, Wenwu; Li, Haiyang; Kong, Liang; Zheng, Xiaobo; Wang, Yuanchao

2015-01-01

267

Sexual self-schemas, sexual dysfunction, and the sexual responses of women with a history of childhood sexual abuse.  

PubMed

Accumulating evidence points to the mediating effects of sexual self-schemas on the sexual difficulties of women with a history of childhood sexual abuse (CSA). The following study adds to the extant literature by investigating (1) sexual function and (2) sexual satisfaction utilizing validated measures, and reporting on the relationship between sexual self-schemas and physiological (vaginal photoplethysmography), subjective, and affective responses during laboratory exposure to sexual stimuli. In a community sample of women with (N = 48) and without (N = 48) a history of CSA, we tested (1) the mediation of negative affect on the relation between sexual self-schemas and sexual function/satisfaction, (2) the mediation of negative affect in the relation between CSA and sexual function/satisfaction, and (3) the mediation of sexual self-schemas in the relation between a history of CSA and negative affect prior to sexual stimuli. We found that more Embarrassed/Conservative and less Romantic/Passionate sexual self-schemas predicted negative affect prior to exposure to sexual stimuli which, in turn, predicted levels of sexual satisfaction. The lower sexual satisfaction of CSA survivors was partially mediated by higher reports of negative affect prior to sexual stimuli. However, negative affect prior to sexual stimuli was not mediated by the sexual self-schemas of CSA survivors. Thus, although sexual self-schemas predicted sexual satisfaction, they did not predict variance in negative affect prior to sexual videos experienced by women with a history of CSA. PMID:21140286

Rellini, Alessandra H; Meston, Cindy M

2011-04-01

268

Reproducibility of ambulatory blood pressure load.  

PubMed

Twenty-two hypertensive patients were monitored during two separate drug-free occasions with a Del Mar Avionics ambulatory device. Blood pressure loads (percentage of systolic and diastolic readings more than 140 and 90 mmHg, respectively) and mean BP were measured both to determine their reproducibility and to examine how they correlate with each other. The systolic and diastolic mean awake BPs for day 1 and day 2 were 140/93 mmHg and 140/91 mmHg, respectively, and BP loads were 45%/55% and 43%/54%. Moreover, mean BP loads correlated highly (r = 0.93) with mean BP values taken on the same day. Both ambulatory mean SBP and BP load were highly reproducible (r = 0.87 and 0.80, respectively, during the awake hours), and mean DBP and load were fairly reproducible (r = 0.59 and 0.39, respectively, during the awake hours). Clinically, however, both were consistent from day 1 to day 2. Mean and individual standard deviations also were reproducible for both systolic and diastolic pressures and loads. PMID:2096203

Zachariah, P K; Sheps, S G; Bailey, K R; Wiltgen, C M; Moore, A G

1990-12-01

269

Natural Disasters: Earth Science Readings. Reproducibles.  

ERIC Educational Resources Information Center

Natural Disasters is a reproducible teacher book that explains what scientists believe to be the causes of a variety of natural disasters and suggests steps that teachers and students can take to be better prepared in the event of a natural disaster. It contains both student and teacher sections. Teacher sections include vocabulary, an answer key,…

Lobb, Nancy

270

Europe Today: An Atlas of Reproducible Pages.  

ERIC Educational Resources Information Center

Illustrative black and white maps, tables, and graphs designed for clear reproducibility depict Europe's size, population, resources, commodities, trade, cities, schooling, jobs, energy, industry, demographic statistics, food, and agriculture. Also included are 33 United States Department of State individual country maps. This volume is intended…

World Eagle, Inc., Wellesley, MA.

271

Reproducibility, Controllability, and Optimization of Lenr Experiments  

Microsoft Academic Search

Low-energy nuclear reaction (LENR) measurements are significantly and increasingly reproducible. Practical control of the production of energy or materials by LENR has yet to be demonstrated. Minimization of costly inputs and maximization of desired outputs of LENR remain for future developments.

David J. Nagel

2006-01-01

272

Reproducibility, Controllability, and Optimization of Lenr Experiments  

NASA Astrophysics Data System (ADS)

Low-energy nuclear reaction (LENR) measurements are significantly and increasingly reproducible. Practical control of the production of energy or materials by LENR has yet to be demonstrated. Minimization of costly inputs and maximization of desired outputs of LENR remain for future developments.

Nagel, David J.

2006-02-01

273

Maintaining sexuality in menopause.  

PubMed

Sexual health in the menopause is a medical challenge because the progressive decline of sexual hormones interacts with the aging process and many psychosocial stressors modulate vulnerability for sexual symptoms (low sexual desire, poor arousal and lubrication, dyspareunia, orgasmic dysfunction and lack of satisfaction). In clinical practice, a coordinated approach is needed to optimally manage the risk for developing female sexual dysfunction (FSD), especially when chronic conditions are present. Biomedical and psychosocial interventions include general education, recognition of signs and symptoms, promotion of health, attention to the partner and individualization of treatment. Counselling to overcome personal and relational difficulties should be always combined with hormonal and non-hormonal strategies to maximize biological signals driving the sexual response. By enhancing women's abilities to cope with sexual changes at midlife, health care providers may significantly optimize healthy aging and partnership. PMID:24879777

Nappi, Rossella E; Martini, Ellis; Martella, Silvia; Capuano, Francesca; Bosoni, David; Giacomini, Sonia; Beraghi, Matteo; Spinillo, Arsenio

2014-03-13

274

ITK: enabling reproducible research and open science.  

PubMed

Reproducibility verification is essential to the practice of the scientific method. Researchers report their findings, which are strengthened as other independent groups in the scientific community share similar outcomes. In the many scientific fields where software has become a fundamental tool for capturing and analyzing data, this requirement of reproducibility implies that reliable and comprehensive software platforms and tools should be made available to the scientific community. The tools will empower them and the public to verify, through practice, the reproducibility of observations that are reported in the scientific literature. Medical image analysis is one of the fields in which the use of computational resources, both software and hardware, are an essential platform for performing experimental work. In this arena, the introduction of the Insight Toolkit (ITK) in 1999 has transformed the field and facilitates its progress by accelerating the rate at which algorithmic implementations are developed, tested, disseminated and improved. By building on the efficiency and quality of open source methodologies, ITK has provided the medical image community with an effective platform on which to build a daily workflow that incorporates the true scientific practices of reproducibility verification. This article describes the multiple tools, methodologies, and practices that the ITK community has adopted, refined, and followed during the past decade, in order to become one of the research communities with the most modern reproducibility verification infrastructure. For example, 207 contributors have created over 2400 unit tests that provide over 84% code line test coverage. The Insight Journal, an open publication journal associated with the toolkit, has seen over 360,000 publication downloads. The median normalized closeness centrality, a measure of knowledge flow, resulting from the distributed peer code review system was high, 0.46. PMID:24600387

McCormick, Matthew; Liu, Xiaoxiao; Jomier, Julien; Marion, Charles; Ibanez, Luis

2014-01-01

275

ITK: enabling reproducible research and open science  

PubMed Central

Reproducibility verification is essential to the practice of the scientific method. Researchers report their findings, which are strengthened as other independent groups in the scientific community share similar outcomes. In the many scientific fields where software has become a fundamental tool for capturing and analyzing data, this requirement of reproducibility implies that reliable and comprehensive software platforms and tools should be made available to the scientific community. The tools will empower them and the public to verify, through practice, the reproducibility of observations that are reported in the scientific literature. Medical image analysis is one of the fields in which the use of computational resources, both software and hardware, are an essential platform for performing experimental work. In this arena, the introduction of the Insight Toolkit (ITK) in 1999 has transformed the field and facilitates its progress by accelerating the rate at which algorithmic implementations are developed, tested, disseminated and improved. By building on the efficiency and quality of open source methodologies, ITK has provided the medical image community with an effective platform on which to build a daily workflow that incorporates the true scientific practices of reproducibility verification. This article describes the multiple tools, methodologies, and practices that the ITK community has adopted, refined, and followed during the past decade, in order to become one of the research communities with the most modern reproducibility verification infrastructure. For example, 207 contributors have created over 2400 unit tests that provide over 84% code line test coverage. The Insight Journal, an open publication journal associated with the toolkit, has seen over 360,000 publication downloads. The median normalized closeness centrality, a measure of knowledge flow, resulting from the distributed peer code review system was high, 0.46. PMID:24600387

McCormick, Matthew; Liu, Xiaoxiao; Jomier, Julien; Marion, Charles; Ibanez, Luis

2014-01-01

276

High variation in clonal vs. sexual reproduction in populations of the wild strawberry, Fragaria virginiana (Rosaceae)  

PubMed Central

Background and Aims Many plants reproduce both clonally and sexually, and the balance between the two modes of reproduction will vary among populations. Clonal reproduction was characterized in three populations of the wild strawberry, Fragaria virginiana, to determine the extent that reproductive mode varied locally between sites. The study sites were fragmented woodlands in Cook County, Illinois, USA. Methods A total of 95 strawberry ramets were sampled from the three sites via transects. Ramets were mapped and genotyped at five variable microsatellite loci. The variability at these five loci was sufficient to assign plants to clones with high confidence, and the spatial pattern of genets was mapped at each site. Key Results A total of 27 distinct multilocus genotypes were identified. Of these, 18 genotypes were detected only once, with the remaining nine detected in multiple ramets. The largest clone was identified in 16 ramets. No genets were shared between sites, and each site exhibited markedly different clonal and sexual recruitment patterns, ranging from two non-overlapping and widespread genets to 19 distinct genets. Only one flowering genet was female; the remainder were hermaphrodites. Conclusions Local population history or fine-scale ecological differences can result in dramatically different reproductive patterns at small spatial scales. This finding may be fairly widespread among clonal plant species, and studies that aim to characterize reproductive modes in species capable of asexual reproduction need to evaluate reproductive modes in multiple populations and sites. PMID:19797422

Wilk, John A.; Kramer, Andrea T.; Ashley, Mary V.

2009-01-01

277

A functional perspective on sexual selection: insights and future prospects  

Microsoft Academic Search

A large number of sexual selection studies have focused on examining the morphological and behavioural factors involved in male combat and female choice, such as whether large males achieve higher reproduc- tive success compared with smaller males. However, until recently, the mechanistic reasons why such cues are linked to male dominance or female choice have been elusive. An emerging body

Simon P. Lailvaux; Duncan J. Irschick

2006-01-01

278

The Effects of Sexual Assault on Sexual Attitudes  

Microsoft Academic Search

As a means of studying the effects of sexual assault on sexual attitudes, two categories of sexual attitude measures taken from the National Health and Social Life Surveys were analyzed. One category contains measures of the appeal of various sexual acts to women; the other assesses general sexual attitudes such as approval of premarital sex. We proposed that women who

Ashley Anne Redfearn; Mary Riege Laner

2000-01-01

279

Adolescent Sexual Behavior and Sexual Education in the United States  

Microsoft Academic Search

This review of sexual education in the United States broadly defines the two most common approaches in sexual education seen in this country today. I cover the status of certain sexual behaviors and risks amongst the teenage population in the U.S. and specifically cover reported sexual activity in high school students and overall data on teen pregnancies and sexually transmitted

Therese B Orbea

2010-01-01

280

RESPONSE TO SEXUAL DISCRIMINATION/HARASSMENT Sexual Harassment  

E-print Network

RESPONSE TO SEXUAL DISCRIMINATION/HARASSMENT Sexual Harassment Sexual harassment is a form of discrimination, as defined in the university Discrimination and Harassment policy. Sexual harassment can include to engage in sexual behavior to further the student's education or employment; real or perceived threat

Mayfield, John

281

Recombination without Sexual Reproduction in Penicillium chrysogenum  

Microsoft Academic Search

THE technique devised by Pontecorvo and Roper1,2 for genetic analysis outside the sexual cycle in filamentous fungi and applied to the imperfect fungus Aspergillus niger3,4 has now been successfully adapted by us to another imperfect fungus, Penicillium chrysogenum, the species used for penicillin production.

G. Pontecorvo; G. Sermonti

1953-01-01

282

Experimental Studies on Sexual Reproduction in Diatoms  

Microsoft Academic Search

The diatoms are the most speciose group of algae, having global ecological significance in the carbon and silicon cycles. They are almost unique among algae in being diplontic, and sexual reproduction is an obligate stage in the life cycle of most diatom species. It is unclear which are the principal factors that have fostered the evolutionary success of diatoms, but

Victor A. Chepurnov; David G. Mann; Koen Sabbe; Wim Vyverman

2004-01-01

283

Sexually Selected Infanticide in a Polygynous Bat  

PubMed Central

Background Adult individuals of many species kill unrelated conspecific infants for several adaptive reasons ranging from predation or resource competition to the prevention of misdirected parental care. Moreover, infanticide can increase the reproductive success of the aggressor by killing the offspring of competitors and thereafter mating with the victimized females. This sexually selected infanticide predominantly occurs in polygynous species, with convincing evidence for primates, carnivores, equids, and rodents. Evidence for bats was predicted but lacking. Methodology/Principal Findings Here we report the first case, to our knowledge, of sexually selected infanticide in a bat, the polygynous white-throated round-eared bat, Lophostoma silvicolum. Behavioral studies in a free-living population revealed that an adult male repeatedly attacked and injured the pups of two females belonging to his harem, ultimately causing the death of one pup. The infanticidal male subsequently mated with the mother of the victimized pup and this copulation occurred earlier than any other in his harem. Conclusions/Significance Our findings indicate that sexually selected infanticide is more widespread than previously thought, adding bats as a new taxon performing this strategy. Future work on other bats, especially polygynous species in the tropics, has great potential to investigate the selective pressures influencing the evolution of sexually selected infanticide and to study how infanticide impacts reproductive strategies and social structures of different species. PMID:21949829

Knörnschild, Mirjam; Ueberschaer, Katja; Helbig, Maria; Kalko, Elisabeth K. V.

2011-01-01

284

Insulin Signaling Mediates Sexual Attractiveness in Drosophila  

Microsoft Academic Search

Sexually attractive characteristics are often thought to reflect an individual's condition or reproductive potential, but the underlying molecular mechanisms through which they do so are generally unknown. Insulin\\/insulin-like growth factor signaling (IIS) is known to modulate aging, reproduction, and stress resistance in several species and to contribute to variability of these traits in natural populations. Here we show that IIS

Tsung-Han Kuo; Tatyana Y. Fedina; Ingrid Hansen; Klaus Dreisewerd; Herman A. Dierick; Joanne Y. Yew; Scott D. Pletcher

2012-01-01

285

Women's Sexuality and Meaning Making  

Microsoft Academic Search

The purpose of the current study was to challenge depictions of traditionally oppressive female sexuality by explicitly exploring diverse women's positive experiences of sexuality and to capture the unique meanings women ascribe to their sexuality through the use of participant-generated metaphor. We interviewed 17 diverse women regarding the meaning of sexuality in their lives. Coding revealed that metaphors for sexuality

Debra Mollen; Sally D. Stabb

2010-01-01

286

Nonvolitional Sex and Sexual Health  

Microsoft Academic Search

Nonvolitional sex is sexual behavior that violates a person's right to choose when and with whom to have sex and what sexual behaviors to engage in. The more extreme forms of this behavior include rape, forced sex, childhood sexual abuse, sex trafficking, and violence against people with nonconventional sexual identities. More nuanced forms of nonvolitional sex include engaging in sexual

Debra Kalmuss

2004-01-01

287

Cultural suppression of female sexuality  

Microsoft Academic Search

Four theories about cultural suppression of female sexuality are evaluated. Data are reviewed on cross-cultural differences in power and sex ratios, reactions to the sexual revolution, direct restraining influences on adolescent and adult female sexuality, double standard patterns of sexual morality, female genital surgery, legal and religious restrictions on sex, prostitution and pornography, and sexual deception. The view that men

Roy F. Baumeister; Jean M. Twenge

2002-01-01

288

Compensating Differentials for Sexual Harassment  

Microsoft Academic Search

Workplace sexual harassment is illegal, but many workers report that they have been sexually harassed. Exposure to the risk of sexual harassment may decrease productivity, which would reduce wages. Alternatively, workers may receive a compensating differential for exposure to sexual harassment, which would increase wages. Data on claims of sexual harassment filed with the Equal Employment Opportunity Commission are used

Joni Hersch

2011-01-01

289

Cultural indicators of sexual harassment  

Microsoft Academic Search

Sexual harassment continues to be pervasive in the workplace. It is doubtful that organizations consciously encourage inappropriate social?sexual behavior, yet the prevalence of sexual harassment suggests that organizations may unofficially or informally sanction behaviors that facilitate or encourage sexual harassment. This study tests a cultural influence model of sexual harassment that explores how sex, victim status, perceptions of fair interpersonal

Joann Keyton; Pat Ferguson; Steven C. Rhodes

2001-01-01

290

Data Identifiers and Citations Enable Reproducible Science  

NASA Astrophysics Data System (ADS)

Modern science often involves data processing with tremendous volumes of data. Keeping track of that data has been a growing challenge for data center. Researchers who access and use that data don't always reference and cite their data sources adequately for consumers of their research to follow their methodology or reproduce their analyses or experiments. Recent research has led to recommendations for good identifiers and citations that can help address this problem. This paper will describe some of the best practices in data identifiers, reference and citation. Using a simplified example scenario based on a long term remote sensing satellite mission, it will explore issues in identifying dynamic data sets and the importance of good data citations for reproducibility. It will describe the difference between granule and collection level identifiers, using UUIDs and DOIs to illustrate some recommendations for developing identifiers and assigning them during data processing. As data processors create data products, the provenance of the input products and precise steps that led to their creation are recorded and published for users of the data to see. As researchers access the data from an archive, they can use the provenance to help understand the genesis of the data, which could have effects on their usage of the data. By citing the data on publishing their research, others can retrieve the precise data used in their research and reproduce the analyses and experiments to confirm the results. Describing the experiment to a sufficient extent to reproduce the research enforces a formal approach that lends credibility to the results, and ultimately, to the policies of decision makers depending on that research.

Tilmes, C.

2011-12-01

291

Detecting sexual conflict and sexually antagonistic coevolution  

PubMed Central

We begin by providing an operational definition of sexual conflict that applies to both inter- and intralocus conflict. Using this definition, we examine a series of simple coevolutionary models to elucidate fruitful approaches for detecting interlocus sexual conflict and resultant sexually antagonistic coevolution. We then use published empirical examples to illustrate the utility of these approaches. Three relevant attributes emerge. First, the dynamics of sexually antagonistic coevolution may obscure the conflict itself. Second, competing models of inter-sexual coevolution may yield similar population patterns near equilibria. Third, a variety of evolutionary forces underlying competing models may be acting simultaneously near equilibria. One main conclusion is that studies of emergent patterns in extant populations (e.g. studies of population and/or female fitness) are unlikely to allow us to distinguish among competing coevolutionary models. Instead, we need more research aimed at identifying the forces of selection acting on shared traits and sexually antagonistic traits. More specifically, we need a greater number of functional studies of female traits as well as studies of the consequences of both male and female traits for female fitness. A mix of selection and manipulative studies on these is likely the most promising route. PMID:16612887

Rowe, Locke; Day, Troy

2006-01-01

292

Disruption of adult expression of sexually selected traits by developmental exposure to bisphenol A  

PubMed Central

Exposure to endocrine disrupting compounds (EDCs), such as bisphenol A (BPA), may cause adverse health effects in wildlife and humans, but controversy remains as to what traits are most sensitive to EDCs and might serve as barometers of exposure. Expression of sexually selected traits that have evolved through intrasexual competition for mates and intersexual choice of mating partner are more dependent on developmental and physical condition of an animal than naturally selected traits and thus might be particularly vulnerable to disruption by developmental exposure to EDCs. We have used the deer mouse (Peromyscus maniculatus) as a model to test this hypothesis. Adult male–male competition for mates in this species is supported by enhanced spatial navigational and exploratory abilities, which enable males to search for prospective, widely dispersed females. Male deer mice exposed to BPA or ethinyl estradiol (EE) through maternal diet showed no changes in external phenotype, sensory development, or adult circulating concentrations of testosterone and corticosterone, but spatial learning abilities and exploratory behaviors were severely compromised compared with control males. Because these traits are not sexually selected in females, BPA exposure predictably had no effect, although EE-exposed females demonstrated enhanced spatial navigational abilities. Both BPA-exposed and control females preferred control males to BPA-exposed males. Our demonstration that developmental exposure to BPA compromises cognitive abilities and behaviors essential for males to reproduce successfully has broad implications for other species, including our own. Thus, sexually selected traits might provide useful biomarkers to assess risk of environmental contamination in animal and human populations. PMID:21709224

Jašarevi?, Eldin; Sieli, Paizlee T.; Twellman, Erin E.; Welsh, Thomas H.; Schachtman, Todd R.; Roberts, R. Michael; Geary, David C.; Rosenfeld, Cheryl S.

2011-01-01

293

Degradation of sexual reproduction in Veronica filiformis after introduction to Europe  

PubMed Central

Background Baker’s law predicts that self-incompatible plant species are generally poor colonizers because their mating system requires a high diversity of genetically differentiated individuals and thus self-compatibility should develop after long-distance dispersal. However, cases like the introduction of the self-incompatible Veronica filiformis (Plantaginaceae) to Europe constitute an often overlooked alternative to this rule. This species was introduced from subalpine areas of the Pontic-Caucasian Mountains and colonized many parts of Central and Western Europe in the last century, apparently without producing seeds. To investigate the consequences of the absence of sexual reproduction in this obligate outcrosser since its introduction, AFLP fingerprints, flower morphology, pollen and ovule production and seed vitality were studied in introduced and native populations. Results Interpopulation crossings of 19 introduced German populations performed in the greenhouse demonstrated that introduced populations are often unable to reproduce sexually. These results were similar to intrapopulation crossings, but this depended on the populations used for crossings. Results from AFLP fingerprinting confirmed a lack of genetic diversity in the area of introduction, which is best explained by the dispersal of clones. Flower morphology revealed the frequent presence of mutations affecting the androecium of the flower and decreasing pollen production in introduced populations. The seeds produced in our experiments were smaller, had a lower germination rate and had lower viability than seeds from the native area. Conclusions Taken together, our results demonstrate that V. filiformis was able to spread by vegetative means in the absence of sexual reproduction. This came at the cost of an accumulation of phenotypically observable mutations in reproductive characters, i.e. Muller’s ratchet. PMID:23198765

2012-01-01

294

Disruption of adult expression of sexually selected traits by developmental exposure to bisphenol A.  

PubMed

Exposure to endocrine disrupting compounds (EDCs), such as bisphenol A (BPA), may cause adverse health effects in wildlife and humans, but controversy remains as to what traits are most sensitive to EDCs and might serve as barometers of exposure. Expression of sexually selected traits that have evolved through intrasexual competition for mates and intersexual choice of mating partner are more dependent on developmental and physical condition of an animal than naturally selected traits and thus might be particularly vulnerable to disruption by developmental exposure to EDCs. We have used the deer mouse (Peromyscus maniculatus) as a model to test this hypothesis. Adult male-male competition for mates in this species is supported by enhanced spatial navigational and exploratory abilities, which enable males to search for prospective, widely dispersed females. Male deer mice exposed to BPA or ethinyl estradiol (EE) through maternal diet showed no changes in external phenotype, sensory development, or adult circulating concentrations of testosterone and corticosterone, but spatial learning abilities and exploratory behaviors were severely compromised compared with control males. Because these traits are not sexually selected in females, BPA exposure predictably had no effect, although EE-exposed females demonstrated enhanced spatial navigational abilities. Both BPA-exposed and control females preferred control males to BPA-exposed males. Our demonstration that developmental exposure to BPA compromises cognitive abilities and behaviors essential for males to reproduce successfully has broad implications for other species, including our own. Thus, sexually selected traits might provide useful biomarkers to assess risk of environmental contamination in animal and human populations. PMID:21709224

Jašarevi?, Eldin; Sieli, Paizlee T; Twellman, Erin E; Welsh, Thomas H; Schachtman, Todd R; Roberts, R Michael; Geary, David C; Rosenfeld, Cheryl S

2011-07-12

295

[Sexuality and urological diseases].  

PubMed

Patients with lower urinary tract symptoms related to benign prostatic hyperplasia (BPH) frequently suffer from sexual dysfunction (erectile dysfunction and ejaculatory dysfunction). Erectile dysfunction and premature ejaculation are two times more common in men with chronic pelvic pain/chronic prostatitis. All treatments of prostate cancer are responsible for sexual dysfunctions. Sexual disorders frequently appear during the management of infertile couples. Information and support should be offered to couples. Women with urinary incontinence also suffer frequently from coital incontinence. PMID:25201599

Droupy, Stéphane

2014-10-01

296

Sexual dysfunction and prostatitis  

Microsoft Academic Search

Despite a large number of reports exploring the links between diseases of the prostate and effects on sexuality, the relationship\\u000a between prostatitis and sexual dysfunction has not been as thoroughly investigated. A number of reports have focused on the\\u000a adverse effects of prostatitis on quality of life, with resultant indirect effects on sexuality. More detailed studies are\\u000a available on the

Hossein Sadeghi-Nejad; Allen Seftel

2006-01-01

297

ORIGINAL PAPER Sexual Self-Schemas, Sexual Dysfunction, and the Sexual Responses  

E-print Network

ORIGINAL PAPER Sexual Self-Schemas, Sexual Dysfunction, and the Sexual Responses of Women with a History of Childhood Sexual Abuse Alessandra H. Rellini · Cindy M. Meston Received: 30 June 2009 / Revised access at Springerlink.com Abstract Accumulating evidence points to the mediating effects of sexual self

Meston, Cindy

298

Academic Sexual Correctness  

NSDL National Science Digital Library

This list on the subject of academic sexual correctness(ASC-L). ASC-L was an outgrowth of CASE (Consenting Academics for Sexual Equity), founded in early 1994 by both professors and students to combat a concerted "feminist" campaign against students and professors who had become involved in an intimate(romantic) relationship. CASE dealt with only one small area of the current emphasis on sexual correctness in academia. Consequently, the need for a network that focused on all aspects of academic sexual correctness became apparent; the ASC-L was a response to that need. ASC-L encompasses all aspects of campus sexual control issues -- irrespective of their ideological origins, such as sexual consent issues, sexual discrimination issues (irrespective of the subjects of the discrimination) and attempts to regulate sexual content of speech on campus or sexual content of course materials. The principles of consent, privacy and academic freedom are the core principles which have motivated the founding of ASC-L.

299

Evolution of sexuality: biology and behavior  

PubMed Central

Sexual reproduction in animals and plants is far more prevalent than asexual reproduction, and there is no dearth of hypotheses attempting to explain why. Even bacteria and viruses, which reproduce by cloning, engage in promiscuous horizontal gene exchange (“parasexual reproduction”) on such short time scales that they evolve genotypic diversity even more rapidly than eukaryotes. (We confront this daily in the form of antimicrobial resistance.) The host-parasite and host-pathogen arms race purports to explain the prevalence of sexual reproduction, yet there are over a dozen other hypotheses, including the proposition that sexual reproduction purges the genome of deleterious mutations. An equally daunting challenge is to understand, in terms of evolutionary logic, the jungle of diverse courtship and mating strategies that we find in nature. The phenotypic plasticity of sex determination in animals suggests that the central nervous system and reproductive tract may not reach the same endpoint on the continuum between our stereotypic male and female extremes. Why are there only two kinds of gametes in most eukaryotes? Why are most flowering plants, and few animals, hermaphroditic? Why do male animals compete more for access to females than the other way around in most animals that have been studied?This review presents more questions than answers, but an extraordinary wealth of data has been collected, and new genetic techniques will provide new answers. The possible relevance of these data to human sexuality will be discussed in a future article. PMID:16200180

2005-01-01

300

Sexual Self-Schemas of Female Child Sexual Abuse Survivors: Relationships with Risky Sexual Behavior and Sexual Assault in Adolescence  

Microsoft Academic Search

Childhood sexual trauma has been demonstrated to increase survivors’ risk for engaging in unrestricted sexual behaviors and\\u000a experiencing adolescent sexual assault. The current study used the sexual self-schema construct to examine cognitive representations\\u000a of sexuality that might drive these behavioral patterns. In Study 1 (N = 774), we attempted to improve the content validity of the Sexual Self Schema Scale for child

Ashley F. NiehausJoan; Joan Jackson; Stephanie Davies

2010-01-01

301

Sexual Self-Schemas, Sexual Dysfunction, and the Sexual Responses of Women with a History of Childhood Sexual Abuse  

Microsoft Academic Search

Accumulating evidence points to the mediating effects of sexual self-schemas on the sexual difficulties of women with a history\\u000a of childhood sexual abuse (CSA). The following study adds to the extant literature by investigating (1) sexual function and\\u000a (2) sexual satisfaction utilizing validated measures, and reporting on the relationship between sexual self-schemas and physiological\\u000a (vaginal photoplethysmography), subjective, and affective responses

Alessandra H. RelliniCindy; Cindy M. Meston

2011-01-01

302

Schemas, sexuality, and romantic attachment  

Microsoft Academic Search

One's self-views are powerful regulators of both cognitive processing and behavioral responding. Sexual self-schemas are cognitive generalizations about sexual aspects of the self. The bivariate sexual self-schema model, which posits independent effects of positive and negative components of women's sexual self-views, was tested. Three hundred eighteen female undergraduates completed anonymous questionnaires, including the Sexual Self-Schema Scale and assessments of sexual

Jill M. Cyranowski; Barbara L. Andersen

1998-01-01

303

Sexual conflict and antagonistic coevolution across water strider populations.  

PubMed

Microevolutionary studies have demonstrated sexually antagonistic selection on sexual traits, and existing evidence supports a macroevolutionary pattern of sexually antagonistic coevolution. Two current questions are how antagonistic selection within-populations scales to divergence among populations, and to what extent intraspecific divergence matches species-level patterns. To address these questions, we conducted an intraspecific comparative study of sexual armaments and mating behaviors in a water strider (Gerris incognitus) in which male genitals grasp resistant females and female abdominal structures help ward off males. The degree of exaggeration of these armaments coevolves across species. We found a similar strong pattern of antagonistic coevolution among populations, suggesting that sexual conflict drives population differentiation in morphology. Furthermore, relative exaggeration in armaments was closely related to mating outcomes in a common environment. Interestingly, the effect of armaments on mating was mediated by population sexual size dimorphism. When females had a large size advantage, mating activity was low and independent of armaments, but when males had a relative size advantage, mating activity depended on which sex had relatively exaggerated armaments. Thus, a strong signal of sexually antagonistic coevolution is apparent even among populations. These results open opportunities to understand links between sexual arms races, ecological variation, and reproductive isolation. PMID:22276547

Perry, Jennifer C; Rowe, Locke

2012-02-01

304

Multivariate sexual selection in a rapidly evolving speciation phenotype.  

PubMed

Estimating the fitness surface of rapidly evolving secondary sexual traits can elucidate the origins of sexual isolation and thus speciation. Evidence suggests that sexual selection is highly complex in nature, often acting on multivariate sexual characters that sometimes include non-heritable components of variation, thus presenting a challenge for predicting patterns of sexual trait evolution. Laupala crickets have undergone an explosive species radiation marked by divergence in male courtship song and associated female preferences, yet patterns of sexual selection that might explain this diversification remain unknown. We used female phonotaxis trials to estimate the fitness surface for acoustic characters within one population of Laupala cerasina, a species with marked geographical variation in male song and female preferences. Results suggested significant directional sexual selection on three major song traits, while canonical rotation of the matrix of nonlinear selection coefficients (?) revealed the presence of significant convex (stabilizing) sexual selection along combinations of characters. Analysis of song variation within and among males indicated significantly higher repeatability along the canonical axis of greatest stabilizing selection than along the axis of greatest linear selection. These results are largely consistent with patterns of song divergence that characterize speciation and suggest that different song characters have the potential to indicate distinct information to females during courtship. PMID:23760640

Oh, Kevin P; Shaw, Kerry L

2013-06-22

305

Multivariate sexual selection in a rapidly evolving speciation phenotype  

PubMed Central

Estimating the fitness surface of rapidly evolving secondary sexual traits can elucidate the origins of sexual isolation and thus speciation. Evidence suggests that sexual selection is highly complex in nature, often acting on multivariate sexual characters that sometimes include non-heritable components of variation, thus presenting a challenge for predicting patterns of sexual trait evolution. Laupala crickets have undergone an explosive species radiation marked by divergence in male courtship song and associated female preferences, yet patterns of sexual selection that might explain this diversification remain unknown. We used female phonotaxis trials to estimate the fitness surface for acoustic characters within one population of Laupala cerasina, a species with marked geographical variation in male song and female preferences. Results suggested significant directional sexual selection on three major song traits, while canonical rotation of the matrix of nonlinear selection coefficients (?) revealed the presence of significant convex (stabilizing) sexual selection along combinations of characters. Analysis of song variation within and among males indicated significantly higher repeatability along the canonical axis of greatest stabilizing selection than along the axis of greatest linear selection. These results are largely consistent with patterns of song divergence that characterize speciation and suggest that different song characters have the potential to indicate distinct information to females during courtship. PMID:23760640

Oh, Kevin P.; Shaw, Kerry L.

2013-01-01

306

Darwin's forgotten idea: the social essence of sexual selection.  

PubMed

Darwinian sexual selection can now be seen in the broader context of social selection, or social competition for resources (under sexual selection, mates or fertilization success). The social-interaction aspects of sexually selected traits give them special evolutionary properties of interest for neurobiological studies of stimulus-response systems because they can account for highly complex systems with little information content other than stimulatory effectiveness per se. But these special properties have a long history of being forgotten when other factors dominate the analysis of male-female interactions, such as the mistaken belief that differential responsiveness to signals produced by competing rivals ("female choice") requires an esthetic sense; that species recognition explains all species-specific sexual signals; and, more recently, that successful signals must reflect good survival genes; or that male-female conflict involves female resistance rather than stimulus evaluation. A "conflict paradox" results when male-female conflict is seen as driven by natural selection, whose costs should often move the hypothesized "sexually antagonistic co-evolution" of sensory-response systems toward the powerful domain of sexually synergistic co-evolution under sexual selection. Special properties of sexual selection apply to other forms of social competition as well, showing the wisdom of Darwin's setting it apart from natural selection as an explanation of many otherwise puzzling and extreme traits. PMID:25003806

West-Eberhard, Mary Jane

2014-10-01

307

Reproducible Clusters from Microarray Research: Whither?  

PubMed Central

Motivation In cluster analysis, the validity of specific solutions, algorithms, and procedures present significant challenges because there is no null hypothesis to test and no 'right answer'. It has been noted that a replicable classification is not necessarily a useful one, but a useful one that characterizes some aspect of the population must be replicable. By replicable we mean reproducible across multiple samplings from the same population. Methodologists have suggested that the validity of clustering methods should be based on classifications that yield reproducible findings beyond chance levels. We used this approach to determine the performance of commonly used clustering algorithms and the degree of replicability achieved using several microarray datasets. Methods We considered four commonly used iterative partitioning algorithms (Self Organizing Maps (SOM), K-means, Clutsering LARge Applications (CLARA), and Fuzzy C-means) and evaluated their performances on 37 microarray datasets, with sample sizes ranging from 12 to 172. We assessed reproducibility of the clustering algorithm by measuring the strength of relationship between clustering outputs of subsamples of 37 datasets. Cluster stability was quantified using Cramer's v2 from a kXk table. Cramer's v2 is equivalent to the squared canonical correlation coefficient between two sets of nominal variables. Potential scores range from 0 to 1, with 1 denoting perfect reproducibility. Results All four clustering routines show increased stability with larger sample sizes. K-means and SOM showed a gradual increase in stability with increasing sample size. CLARA and Fuzzy C-means, however, yielded low stability scores until sample sizes approached 30 and then gradually increased thereafter. Average stability never exceeded 0.55 for the four clustering routines, even at a sample size of 50. These findings suggest several plausible scenarios: (1) microarray datasets lack natural clustering structure thereby producing low stability scores on all four methods; (2) the algorithms studied do not produce reliable results and/or (3) sample sizes typically used in microarray research may be too small to support derivation of reliable clustering results. Further research should be directed towards evaluating stability performances of more clustering algorithms on more datasets specially having larger sample sizes with larger numbers of clusters considered. PMID:16026595

Garge, Nikhil R; Page, Grier P; Sprague, Alan P; Gorman, Bernard S; Allison, David B

2005-01-01

308

Genetic diversity in sexual diploid and apomictic tetraploid populations of Paspalum notatum situated in sympatry or allopatry  

Microsoft Academic Search

Paspalum notatum is a subtropical grass widely distributed in the temperate areas of America. Diploids are sexual while polyploids give rise to clonal seeds through aposporous apomixis. RAPD markers were used to analyze the genetic structure of three natural populations: i) diploids reproducing sexually (R2X); ii) sympatric apomictic tetraploids collected in the vicinity of the diploids (R4X); iii) allopatric apomictic

L. D. Daurelio; F. Espinoza; C. L. Quarin; S. C. Pessino

2004-01-01

309

Sexual differences in coloration of Coenagrionid damselflies (Odonata): a case of intraspecific aposematism?  

Microsoft Academic Search

Sexual dimorphism is commonly explained as a consequence of selection on traits that increase male attractiveness to females, or simply allow males greater access to females. Here, we consider another explanation for sexual differences in coloration within species of the damselfly family Coenagrionidae (Odonata: Zygoptera). In many of these species, males are more brightly coloured than females and have different

Thomas N. Sherratt; Mark R. Forbes

2001-01-01

310

Selection on apomictic lineages of Taraxacum at establishment in a mixed sexual-apomictic population  

Microsoft Academic Search

apomixis; asexuality; evolution; polyploidy; selection; Taraxacum. Abstract A species' mode of reproduction, sexual or asexual, will affect its ecology and evolution. In many species, asexuality is related to polyploidy. In Taraxacum, apomicts are triploid, and sexuals are diploid. To disentangle the effects of ploidy level and reproductive mode on life-history traits, we compared established apomictic Taraxacum genotypes with newly synthesized

De Kovel; De Jong

2000-01-01

311

Hormones and history: The evolution and development of primate female sexuality  

Microsoft Academic Search

Sexual behavior is required for reproduction in internally fertilizing species but poses significant social and physical risks. Females in many nonprimate species have evolved physical and behavioral mechanisms restricting sexual behavior to when females are fertile. The same hormones producing female fertility also control these mechanisms, assuring that sex only occurs when reproduction is possible. In contrast to nonprimate mammals,

Kim Wallen; Julia L. Zehr

2004-01-01

312

Mimetic butterflies support Wallace's model of sexual dimorphism.  

PubMed

Theoretical and empirical observations generally support Darwin's view that sexual dimorphism evolves due to sexual selection on, and deviation in, exaggerated male traits. Wallace presented a radical alternative, which is largely untested, that sexual dimorphism results from naturally selected deviation in protective female coloration. This leads to the prediction that deviation in female rather than male phenotype causes sexual dimorphism. Here I test Wallace's model of sexual dimorphism by tracing the evolutionary history of Batesian mimicry-an example of naturally selected protective coloration-on a molecular phylogeny of Papilio butterflies. I show that sexual dimorphism in Papilio is significantly correlated with both female-limited Batesian mimicry, where females are mimetic and males are non-mimetic, and with the deviation of female wing colour patterns from the ancestral patterns conserved in males. Thus, Wallace's model largely explains sexual dimorphism in Papilio. This finding, along with indirect support from recent studies on birds and lizards, suggests that Wallace's model may be more widely useful in explaining sexual dimorphism. These results also highlight the contribution of naturally selected female traits in driving phenotypic divergence between species, instead of merely facilitating the divergence in male sexual traits as described by Darwin's model. PMID:18426753

Kunte, Krushnamegh

2008-07-22

313

Reproducibility Data on SUMMiT  

SciTech Connect

SUMMiT (Sandia Ultra-planar Multi-level MEMS Technology) at the Sandia National Laboratories' MDL (Microelectronics Development Laboratory) is a standardized MEMS (Microelectromechanical Systems) technology that allows designers to fabricate concept prototypes. This technology provides four polysilicon layers plus three sacrificial oxide layers (with the third oxide layer being planarized) to enable fabrication of complex mechanical systems-on-a-chip. Quantified reproducibility of the SUMMiT process is important for process engineers as well as designers. Summary statistics for critical MEMS technology parameters such as film thickness, line width, and sheet resistance will be reported for the SUMMiT process. Additionally, data from Van der Pauw test structures will be presented. Data on film thickness, film uniformity and critical dimensions of etched line widths are collected from both process and monitor wafers during manufacturing using film thickness metrology tools and SEM tools. A standardized diagnostic module is included in each SWiT run to obtain post-processing parametric data to monitor run-to-run reproducibility such as Van der Pauw structures for measuring sheet resistance. This characterization of the SUMMiT process enables design for manufacturability in the SUMMiT technology.

Irwin, Lloyd; Jakubczak, Jay; Limary, Siv; McBrayer, John; Montague, Stephen; Smith, James; Sniegowski, Jeffry; Stewart, Harold; de Boer, Maarten

1999-07-16

314

Morpho-blue reproduced by nanocasting lithography  

NASA Astrophysics Data System (ADS)

The brilliant metallic blue in wings of Morpho butterflies has a mysterious feature. The blue luster is produced from the butterfly's scale, which does not contain a blue pigment at all. The origin of the coloration is then attributed to a microscopic structure that can also explain its high reflectivity. However, its optical characteristics on the scattered wavelength contradicts obviously the grating or multilayer, because it appears blue from wide angle. The mystery of the lack of multi-coloration has recently been explained using a model with a peculiar optical structure, and experimentally proven by fabricating the optical film by controlling the parameters in nanoscale. The reproduced Morpho-blue was found to be important from viewpoint of a wide variety of applications. However, the fabrication process of the nano- structure is too costly due to conventional lithography method. To solve the problem, nano-casting lithography (NCL) was newly applied using UV curable polymer to replicate the nanostructure and improve heat-resistance for the following process of deposition. After fabrication of the nano-patterned polymer structure by the NCL, TiO II and SiO II layers were deposited and the Morpho-blue structure was successfully replicated in low cost. The reflective characteristic of the replicated structure was found to reproduce the basic properties of the natural Morpho-blue, as well as the originally fabricated Morpho-blue.

Saito, Akira; Nakajima, Masaki; Miyamura, Yusuke; Sogo, Kenji; Ishikawa, Yoko; Hirai, Yoshihiko

2006-08-01

315

Asexual and sexual replication in sporulating organisms  

NASA Astrophysics Data System (ADS)

Replication via sporulation is the replication strategy for all multicellular life, and may even be observed in unicellular life (such as with budding yeast). We consider diploid populations replicating via one of two possible sporulation mechanisms. (1) Asexual sporulation, whereby adult organisms produce single-celled diploid spores that grow into adults themselves. (2) Sexual sporulation, whereby adult organisms produce single-celled diploid spores that divide into haploid gametes. The haploid gametes enter a haploid “pool,” where they may recombine with other haploids to form a diploid spore that then grows into an adult. We consider a haploid fusion rate given by second-order reaction kinetics. We work with a simplified model where the diploid genome consists of only two chromosomes, each of which may be rendered defective with a single point mutation of the wild-type. We find that the asexual strategy is favored when the rate of spore production is high compared to the characteristic growth rate from a spore to a reproducing adult. Conversely, the sexual strategy is favored when the rate of spore production is low compared to the characteristic growth rate from a spore to a reproducing adult. As the characteristic growth time increases, or as the population density increases, the critical ratio of spore production rate to organism growth rate at which the asexual strategy overtakes the sexual one is pushed to higher values. Therefore, the results of this model suggest that, for complex multicellular organisms, sexual replication is favored at high population densities and low growth and sporulation rates.

Lee, Bohyun; Tannenbaum, Emmanuel

2007-08-01

316

Sexual Dysfunction in Uremia  

Microsoft Academic Search

Disturbances in sexual function are a common feature of chronic renal failure. Approximately 50% of uremic men com- plain of erectile dysfunction while an even greater percentage of both men and women complain of decreased libido and a marked decline in the frequency of intercourse (1,2). The genesis of sexual dysfunction is multifactorial and is primarily organic in origin. In

BIFF F. PALMER

317

[Sexuality in the elderly].  

PubMed

Sustaining and strengthening the ability of the elderly to continue their sexual needs can be realized as part of improving their quality of life, health and well-being. There is no age at which ends the expression of sexuality and intimacy. Through education, quality of life and advances in medicine, the average life expectancy is still increasing. Sexual activity of older people society usually describe using pejorative terms as an inappropriate, bizarre or obscene, but these labels are different than reality. Hormonal changes and other physiological changes associated with aging affect sexual interest. Erectile dysfunction is a problem in men increasing with age. There is no evidence that premature ejaculation is more common in older age. Cross-sectional studies showed no difference in sexual dysfunction between older and younger women. Age is not a barrier to sexually transmitted diseases. The most common pathogenetic factors for male erectile dysfunction are vascular diseases. In women, the most important symptoms of sexual dysfunction are lack of emotional wellbeing and a sense of intimacy during sexual intercourse. PMID:25815611

Wilk, Bartosz

2015-02-25

318

Sexuality Sensitive Schooling  

ERIC Educational Resources Information Center

American schools, especially their physical education and sport programs, provide some of the most hostile social geographies in all of society for gay youth. With the aim of transforming schools toward more democratic and sexuality sensitive institutions, this paper reviews the literature on sexuality and education. In the review, three themes,…

McCaughtry, Nate; Dillon, Suzanna; Jones, Elizabeth; Smigell, Sara

2005-01-01

319

The Sexual Genogram.  

ERIC Educational Resources Information Center

The sexual genogram combines aspects of the sex history with the genogram/family journey to examine the impact of the partners' family loyalties, secrets, and "scripts" on their sexual functioning. The exploration process offers an opportunity for major change to occur. Technique for this method is discussed, along with relevant case…

Hof, Larry; Berman, Ellen

1986-01-01

320

Speciation and sexual conict  

Microsoft Academic Search

We review mathematical models that explicitly consider the dynamics of evolutionary change driven by sexual conict over mating rate. Overall, there are at least six dieren t dynamic regimes observed in models of sexual conict: (1) continuous coevolutionary chase between the sexes (which can result in allopatric speciation as a byproduct), (2) evolution towards an equilibrium, (3) cyclic evolution, (4)

Sergey Gavriletsy; Takehiko I. Hayashi

2005-01-01

321

BPH and Sexuality  

Microsoft Academic Search

Quality of life has become a very important parameter in benign prostatic hyperplasia (BPH) and one of the major concepts identified by the patients to be important is related to sexuality after BPH therapy. The impact on sexuality resulting from the various treatment modalities of BPH, either medical, surgical or instrumental has been too often neglected in the past and

Alexandre R. Zlotta; Claude C. Schulman

1999-01-01

322

Sexual Murderers' Implicit Theories  

ERIC Educational Resources Information Center

Interviews with 28 sexual murderers were subjected to grounded theory analysis. Five implicit theories (ITs) were identified: dangerous world, male sex drive is uncontrollable, entitlement, women as sexual objects, and women as unknowable. These ITs were found to be identical to those identified in the literature as being present in rapists. The…

Beech, Anthony; Fisher, Dawn; Ward, Tony

2005-01-01

323

Battling Sexual Abuse  

ERIC Educational Resources Information Center

From costly lawsuits on behalf of victims to negative media coverage, districts can face potentially devastating consequences as a result of sexual abuse of their students by district employees. This article offers a few tips on how to battle sexual abuse particularly in school districts. The author stresses that by adopting strong policies that…

Dessoff, Alan

2010-01-01

324

Maternal Sexuality and Breastfeeding  

ERIC Educational Resources Information Center

In this paper I consider the ways in which lactation has been discussed as a form of maternal sexuality, and the implications this carries for our understanding of breastfeeding practices and sexuality. Drawing on knowledge constructed in the western world during the last half of the twentieth century, the paper identifies a shift between the…

Bartlett, Alison

2005-01-01

325

Am I Sexually Normal?  

MedlinePLUS

Who hasn't compared her sex life with a friend's and wondered, "Why don't I have sex three times a day? Or five orgasms in one night? Is there something wrong with me or my partner? Am I sexually normal?" Even though I am a physician, I learned more about sexuality from friends, partners and ...

326

Maternal sexuality and breastfeeding  

Microsoft Academic Search

In this paper I consider the ways in which lactation has been discussed as a form of maternal sexuality, and the implications this carries for our understanding of breastfeeding practices and sexuality. Drawing on knowledge constructed in the western world during the last half of the twentieth century, the paper identifies a shift between the radical ideologies of the 1960s

Alison Bartlett

2005-01-01

327

Treating Sexually Aggressive Children.  

ERIC Educational Resources Information Center

Although clinical and empirical data have been offered about sexually aggressive children, few have suggested the necessary components of clinical treatment protocols for them. This article reviews the plausible etiologies and the correlates of sexual aggression by children to delineate the necessary treatment elements for them and their families.…

Miranda, Alexis O.; Biegler, Bryan N.; Davis, Kathleen; Frevert, Vada S.; Taylor, Julie

2001-01-01

328

Sexual Reproduction and Breeding  

Technology Transfer Automated Retrieval System (TEKTRAN)

In the second edition of Plant Propagation Concepts and Laboratory Exercises, we have combined the first edition chapters 36: Sexual Reproduction in Angiosperms and 37: Breeding Horticultural Plants into the present single chapter Sexual Reproduction and Breeding. These topics are so closely relate...

329

Sexual Issues (Concerns, Harassment,  

E-print Network

Sexual Issues (Concerns, Harassment, Assault, etc.) Student Survey Items (Survey names listed in blue) #12;Student Survey Feedback by Topical Area: Sexual Issues (Concerns, Harassment, Assault, etc of the following: Services for victims of crime and harassment Freedom from harassment on campus Rules governing

Baltisberger, Jay H.

330

Sexual Harassment in Nursing.  

ERIC Educational Resources Information Center

Sexual harassment in the workplace, specifically in nursing, is discussed. The impact of sexual harassment, characteristics of those commonly involved, the need for changing attitudes of men and women in the workplace, the factor of power in relationships, and ways to avoid legal suits are all examined. (CT)

Duldt, Bonnie W.

1982-01-01

331

Myths of Sexuality Education  

Microsoft Academic Search

This paper suggests that sexuality education needs to take into account the myths by which teachers educate and students learn. Here myth is understood as a narrative, paradigm or vision. The paper does not argue against myth. Rather, it argues that myth or narrative provides a much needed depth dimension to sexuality education. It does argue, however, that the existing

Ronald Morris

1997-01-01

332

Sexual victimization, fear of sexual powerlessness, and cognitive emotion dysregulation as barriers to sexual assertiveness in college women.  

PubMed

The current study examined sexual victimization and two barriers to young women's sexual assertiveness: fear of sexual powerlessness and cognitive emotion dysregulation. College women (N = 499) responded to surveys and indicated that fear of sexual powerlessness and, to a lesser extent, cognitive emotion dysregulation were barriers to sexual assertiveness. Compared with nonvictims, sexually victimized women had greater problems with sexual assertiveness, fear of sexual powerlessness, and cognitive emotion dysregulation. Among victims, fear of sexual powerlessness and emotion dysregulation interacted to impede sexual assertiveness. Findings support targeting identified barriers in interventions to improve sexual assertiveness and reduce risk for unwanted sexual experiences and sexual victimization. PMID:24379216

Zerubavel, Noga; Messman-Moore, Terri L

2013-12-01

333

Sexual Desire Disorders  

PubMed Central

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 physiological changes of humans during sexual stimulation and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition this article will review the current literature on the desire disorders focusing on prevalence, etiology, and treatment. PMID:19727285

Montgomery, Keith A.

2008-01-01

334

Comprehensive phylogenetic analysis of all species of swordtails and platies (Pisces: Genus Xiphophorus) uncovers a hybrid origin of a swordtail fish, Xiphophorus monticolus, and demonstrates that the sexually selected sword originated in the ancestral lineage of the genus, but was lost again secondarily  

PubMed Central

Background Males in some species of the genus Xiphophorus, small freshwater fishes from Meso-America, have an extended caudal fin, or sword – hence their common name “swordtails”. Longer swords are preferred by females from both sworded and – surprisingly also, non-sworded (platyfish) species that belong to the same genus. Swordtails have been studied widely as models in research on sexual selection. Specifically, the pre-existing bias hypothesis was interpreted to best explain the observed bias of females in presumed ancestral lineages of swordless species that show a preference for assumed derived males with swords over their conspecific swordless males. However, many of the phylogenetic relationships within this genus still remained unresolved. Here we construct a comprehensive molecular phylogeny of all 26 known Xiphophorus species, including the four recently described species (X. kallmani, X. mayae, X. mixei and X. monticolus). We use two mitochondrial and six new nuclear markers in an effort to increase the understanding of the evolutionary relationships among the species in this genus. Based on the phylogeny, the evolutionary history and character state evolution of the sword was reconstructed and found to have originated in the common ancestral lineage of the genus Xiphophorus and that it was lost again secondarily. Results We estimated the evolutionary relationships among all known species of the genus Xiphophorus based on the largest set of DNA markers so far. The phylogeny indicates that one of the newly described swordtail species, Xiphophorus monticolus, is likely to have arisen through hybridization since it is placed with the southern platyfish in the mitochondrial phylogeny, but with the southern swordtails in the nuclear phylogeny. Such discordance between these two types of markers is a strong indication for a hybrid origin. Additionally, by using a maximum likelihood approach the possession of the sexually selected sword trait is shown to be the most likely ancestral state for the genus Xiphophorus. Further, we provide a well supported estimation of the phylogenetic relationships between the previously unresolved northern swordtail groups. Conclusions This comprehensive molecular phylogeny of the entire genus Xiphophorus provides evidence that a second swordtail species, X. monticolus, arose through hybridization. Previously, we demonstrated that X. clemenciae, another southern swordtail species, arose via hybridization. These findings highlight the potential key role of hybridization in the evolution of this genus and suggest the need for further investigations into how hybridization contributes to speciation more generally. PMID:23360326

2013-01-01

335

University of Alberta Sexual Assault Centre Reporting a Sexual Assault  

E-print Network

University of Alberta Sexual Assault Centre Reporting a Sexual Assault When deciding whether or not to report a sexual assault, it is important to know what will be involved in the process so you can make a sexual assault to the Edmonton Police Service (EPS) or to University of Alberta Protective Services (UAPS

Machel, Hans

336

Outcomes of Sexual Behaviors among Sexual Minority Youth  

ERIC Educational Resources Information Center

Very little is known about outcomes of sexual behavior for sexual minority youth. In this chapter, I review relevant literature and draw on findings from my own research to initiate an inquiry into this important topic. I begin with a brief overview of the range of sexual behaviors of sexual minority adolescents and young adults. Next, I describe…

Morgan, Elizabeth M.

2014-01-01

337

Sexual Dissonances: or the ‘impossibility’ of sexuality education  

Microsoft Academic Search

This paper examines the discursive formations around sexuality education with special reference to the contemporary period. It sketches the recent history of sexuality politics in Britain, understood in terms of the dynamic relation between New Right movements and sexual radicalisms. It then identifies four discursive clusters: those associated with Neo?Conservatism, ‘the family’ and conservative homophobia; neo?liberal views on sexuality and

Richard Johnson

1996-01-01

338

College Students' Sexual Attitudes and Behaviors: Implications for Sexuality Education  

Microsoft Academic Search

This study of sexual attitudes and behaviors of students in a large northeastern community college was undertaken in partial response to an outspoken community group's claims that the sexuality education courses being taught at the school were undermining the morality of its young adults and encouraging early sexual activity. Findings from 1,825 pretest respondents in human sexuality and general health

Rhona Feigenbaum; Estelle Weinstein; Efrem Rosen

1995-01-01

339

Mating system change reduces the strength of sexual selection in an American frontier population of the 19th century  

Microsoft Academic Search

Sexual selection, or competition among members of one sex for reproductive access to the other, is one of the strongest and fastest evolutionary processes. Comparative studies support the prediction that sexual selection is stronger in polygamous than in monogamous species. We report the first study of the effect on sexual selection of a change in mating system, from polygyny to

Jacob A. Moorad; Daniel E. L. Promislow; Ken R. Smith; Michael J. Wade

2011-01-01

340

Multiple causes of sexual segregation in European red deer: enlightenments from varying breeding phenology at high and low latitude  

Microsoft Academic Search

Sexual segregation outside the mating season occurs in most species of sexually dimorphic ungulates and has been extensively described in the literature, but the mechanisms causing segregation are still debated. The detailed pattern of sexual segregation throughout the year has rarely been presented for mammals, and no study, to our knowledge, has used latitudinal-related variation in breeding phenology to shed

Christophe Bonenfant; Leif E. Loe; Atle Mysterud; Rolf Langvatn; N. C. Stenseth; Jean-Michel Gaillard; Francois Klein

2004-01-01

341

Sexual reproduction of the Hawaiian black coral Antipathes griggi (Cnidaria: Antipatharia)  

NASA Astrophysics Data System (ADS)

The Hawaiian black coral fishery has maintained steady catch levels for over 50 years. However, recent declines in the biomass of commercially valuable Hawaiian black corals question whether regulations need to be redefined for sustainable harvesting. Fishery management efforts are complicated by the limited information on the basic life history and reproduction of black corals. To address this knowledge gap, we used histological techniques to investigate sexual reproductive processes within Antipathes griggi, the dominant species targeted by the fishery. Our results indicate that A. griggi is likely gonochoric with a 1:1 sex ratio and has an annual reproductive cycle. Furthermore, the percentage of polyps containing gametes dropped continuously throughout the reproductive season, indicating that spawning occurs in successive events with greatest intensity between November and December. Current fishing regulations prohibit harvesting of colonies <90 cm in height in state waters, and colonies <120 cm in height in federal waters. This study indicates that ~80% meeting the state harvesting limit, and ~90% of colonies meeting the federal limit, are sexually mature. Therefore, increasing these minimum size harvesting limits would ensure that more colonies can reproduce before being exposed to fishing mortality. Although A. griggi can be found to depths of 100 m, it is rare below the 75 m depth limit at which commercial harvest occurs in Hawai`i. Thus, the supposed depth refuge from harvest does not really exist.

Wagner, D.; Waller, R. G.; Montgomery, A. D.; Kelley, C. D.; Toonen, R. J.

2012-09-01

342

Reproducing the kinematics of damped Lyman ? systems  

NASA Astrophysics Data System (ADS)

We examine the kinematic structure of damped Lyman ? systems (DLAs) in a series of cosmological hydrodynamic simulations using the AREPO code. We are able to match the distribution of velocity widths of associated low-ionization metal absorbers substantially better than earlier work. Our simulations produce a population of DLAs dominated by haloes with virial velocities around 70 km s-1, consistent with a picture of relatively small, faint objects. In addition, we reproduce the observed correlation between velocity width and metallicity and the equivalent width distribution of Si II. Some discrepancies of moderate statistical significance remain; too many of our spectra show absorption concentrated at the edge of the profile and there are slight differences in the exact shape of the velocity width distribution. We show that the improvement over previous work is mostly due to our strong feedback from star formation and our detailed modelling of the metal ionization state.

Bird, Simeon; Haehnelt, Martin; Neeleman, Marcel; Genel, Shy; Vogelsberger, Mark; Hernquist, Lars

2015-02-01

343

New insights into the regulation of sexual reproduction in Closterium.  

PubMed

The genus Closterium, which is the closest unicellular relative to land plants, is the best-characterized charophycean green alga with respect to the process of sexual reproduction. In two representative heterothallic species, the steps and methods of intercellular communication were fully described. Glycoproteinaceous sex pheromones involved in the progress of these processes were physiologically and biochemically characterized and the corresponding genes were cloned. These pheromones function in most steps of sexual reproduction. For elucidating the mechanisms of sexual reproduction in detail, molecular tools such as expressed sequence tag, microarray analysis, and genetic transformation systems have been established, and whole genome analyses are ongoing. Finally, sexual reproductive isolation among mating groups was characterized, and the mechanism involved in this isolation was considered with respect to sex pheromones. In homothallic Closterium, the presence of a pheromone orthologous to the heterothallic type and possible sexual differentiation were also described, through the combination of closely related heterothallic cells. PMID:22608564

Sekimoto, Hiroyuki; Abe, Jun; Tsuchikane, Yuki

2012-01-01

344

Sexual selection accelerates signal evolution during speciation in birds  

PubMed Central

Sexual selection is proposed to be an important driver of diversification in animal systems, yet previous tests of this hypothesis have produced mixed results and the mechanisms involved remain unclear. Here, we use a novel phylogenetic approach to assess the influence of sexual selection on patterns of evolutionary change during 84 recent speciation events across 23 passerine bird families. We show that elevated levels of sexual selection are associated with more rapid phenotypic divergence between related lineages, and that this effect is restricted to male plumage traits proposed to function in mate choice and species recognition. Conversely, we found no evidence that sexual selection promoted divergence in female plumage traits, or in male traits related to foraging and locomotion. These results provide strong evidence that female choice and male–male competition are dominant mechanisms driving divergence during speciation in birds, potentially linking sexual selection to the accelerated evolution of pre-mating reproductive isolation. PMID:23864596

Seddon, Nathalie; Botero, Carlos A.; Tobias, Joseph A.; Dunn, Peter O.; MacGregor, Hannah E. A.; Rubenstein, Dustin R.; Uy, J. Albert C.; Weir, Jason T.; Whittingham, Linda A.; Safran, Rebecca J.

2013-01-01

345

Development of sexual dimorphism in the Drosophila testis  

PubMed Central

The creation of sexual dimorphism in the gonads is essential for producing the male and female gametes required for sexual reproduction. Sexual development of the gonads involves both somatic cells and germ cells, which often undergo sex determination by different mechanisms. While many sex-specific characteristics evolve rapidly and are very different between animal species, gonad function and the formation of sperm and eggs appear more similar and may be more conserved. Consistent with this, the doublesex/mab3 Related Transcription factors (DMRTs) are important for gonad sexual dimorphism in a wide range of animals, including flies, worms and mammals. Here we explore how sexual dimorphism is regulated in the Drosophila gonad, focusing on recent discoveries relating to testis development. We will discuss how sex determination in both the germline and the soma are utilized to create a testis, including the role of the key somatic sex determination factor doublesex. PMID:23087832

Whitworth, Cale; Jimenez, Erin; Van Doren, Mark

2012-01-01

346

Reproducible research: a bioinformatics case study.  

PubMed

While scientific research and the methodologies involved have gone through substantial technological evolution the technology involved in the publication of the results of these endeavors has remained relatively stagnant. Publication is largely done in the same manner today as it was fifty years ago. Many journals have adopted electronic formats, however, their orientation and style is little different from a printed document. The documents tend to be static and take little advantage of computational resources that might be available. Recent work, Gentleman and Temple Lang (2003), suggests a methodology and basic infrastructure that can be used to publish documents in a substantially different way. Their approach is suitable for the publication of papers whose message relies on computation. Stated quite simply, Gentleman and Temple Lang (2003) propose a paradigm where documents are mixtures of code and text. Such documents may be self-contained or they may be a component of a compendium which provides the infrastructure needed to provide access to data and supporting software. These documents, or compendiums, can be processed in a number of different ways. One transformation will be to replace the code with its output -- thereby providing the familiar, but limited, static document.

In this paper we apply these concepts to a seminal paper in bioinformatics, namely The Molecular Classification of Cancer, Golub et al (1999). The authors of that paper have generously provided data and other information that have allowed us to largely reproduce their results. Rather than reproduce this paper exactly we demonstrate that such a reproduction is possible and instead concentrate on demonstrating the usefulness of the compendium concept itself. PMID:16646837

Gentleman, Robert

2005-01-01

347

Sexual sadism and sadistic personality disorder in sexual homicide.  

PubMed

Controversies exist about the diagnostic validity of sexual sadism and its relation to sadistic personality disorder in sex offenders. The aim of this study was to investigate which diagnostic, developmental, and criminal characteristics differentiate sexual sadistic from non-sadistic sexual homicide perpetrators. Psychiatric court reports on 166 men who had committed a sexual homicide were evaluated regarding psychiatric, sexual and criminal history. Sixty-one offenders (36.7%) with sexual sadism (SeSd) were compared with 105 (63.3%) offenders without this diagnosis (NSeSd). Besides the sexual sadistic symptoms, there were seven factors that discriminated best between the two groups (sexual masochism, sadistic personality disorder, isolation in childhood, multiple sexual homicide, previous rape, previous tendencies for similar behavior, and long duration of the homicidal act). Sexual sadism is connected with circumscribed other characteristics and has to be considered in risk assessment and treatment of sex offenders. PMID:17192143

Hill, Andreas; Habermann, Niels; Berner, Wolfgang; Briken, Peer

2006-12-01

348

Sexual selection affects local extinction and turnover in bird communities  

USGS Publications Warehouse

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.

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

2003-01-01

349

Prenatal endocrine influences on sexual orientation and on sexually differentiated childhood behavior  

PubMed Central

Both sexual orientation and sex-typical childhood behaviors, such as toy, playmate and activity preferences, show substantial sex differences, as well as substantial variability within each sex. In other species, behaviors that show sex differences are typically influenced by exposure to gonadal steroids, particularly testosterone and its metabolites, during early development (prenatally or neonatally). This article reviews the evidence regarding prenatal influences of gonadal steroids on human sexual orientation, as well as sex-typed childhood behaviors that predict subsequent sexual orientation. The evidence supports a role for prenatal testosterone exposure in the development of sex-typed interests in childhood, as well as in sexual orientation in later life, at least for some individuals. It appears, however, that other factors, in addition to hormones, play an important role in determining sexual orientation. These factors have not been well-characterized, but possibilities include direct genetic effects, and effects of maternal factors during pregnancy. Although a role for hormones during early development has been established, it also appears that there may be multiple pathways to a given sexual orientation outcome and some of these pathways may not involve hormones. PMID:21333673

Hines, Melissa

2012-01-01

350

Sexual, fecundity, and viability selection on flower size and number in a sexually dimorphic plant.  

PubMed

The evolution of sexual dimorphism will depend on how sexual, fecundity and viability selection act within each sex, with the different forms of selection potentially operating in opposing directions. We examined selection in the dioecious plant Silene latifolia using planted arrays of selection lines that differed in flower size (small vs. large). In this species, a flower size/number trade-off exists within each sex, and males produce smaller and more numerous flowers than females. Moreover, floral traits are genetically correlated with leaf physiology. Sexual selection favoring males in the small-flower line occurred via greater overlap in the timing of flower output between males from this line and females. Fecundity selection favored males with high flower production, as siring success was proportionate to pollen production. Viability selection opposed sexual selection, favoring males from the large-flower line. In females, fecundity and viability selection operated in the same direction, favoring those from the large-flower line via greater seed production and survival. These results concur with the pattern of floral sexual dimorphism. Together with previous results they suggest that the outcome of the different forms of selection will be environmentally dependent, and therefore help to explain variation among populations in sexually dimorphic traits. PMID:22486695

Delph, Lynda F; Herlihy, Christopher R

2012-04-01

351

Sexual Identity Trajectories Among Sexual-Minority Youths: Gender Comparisons  

Microsoft Academic Search

The present investigation explored gender differences in sexual identity development—first same-sex attractions, self-labeling, same-sex sexual contact, and disclosure—among 164 sexual-minority young adults. Based on interviews, results indicated the value of assessing gender differences in the context, timing, spacing, and sequencing of sexual identity milestones. Adolescent males had an earlier onset of all milestones except disclosure. The context for sexual identity

Ritch C. Savin-Williams; Lisa M. Diamond

2000-01-01

352

Effects of feeding level and sexual maturation on carcass and fillet characteristics and indices of protein degradation in rainbow trout (Oncorhynchus mykiss)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sexual maturation in many species of fish including salmonids requires mobilization of energy and nutrient resources to support gonad growth. During sexual maturation, particularly vitellogenesis, proteins are mobilized from muscle tissue, which is evidenced by increased expression of proteolytic g...

353

Drug-induced sexual dysfunction  

Microsoft Academic Search

Drug-induced sexual dysfunction is a relatively common yet poorly understood clinical problem. The mechanisms whereby various drug classes alter sexual function remain poorly documented. An attempt has been made, based on recent advances in sexual physiology, to clarify drug-induced sexual dysfunction on the basis of possible or probable mechanisms of action. It is hoped that this approach may ultimately allow

Irwin Goldstein; Robert J. Krane

1983-01-01

354

Human Sexuality: Responsible Life Choices.  

ERIC Educational Resources Information Center

This book provides a complete course in human sexuality. It can also be used to supplement a family living course. Text content provides current information for teaching high school students about sexuality issues. The text offers basic information on growth and development, sexual development, pregnancy, and birth. It explains the sexual decision…

Ryder, Verdene; Smith, Peggy B.

355

Research in Human Sexuality Education  

ERIC Educational Resources Information Center

Medical students' attitudes towards concepts in sexuality before and after a five-day sexuality course were tested at the University of Miami School of Medicine and evaluated with Osgood's Semantic Differential. Concepts rated were "my sexuality,""masturbation,""homosexuality," and "my role in understanding sexual problems." (LBH)

Carmichael, Joan; And Others

1977-01-01

356

Sexual Assaults CRIME PREVENTION UNIT  

E-print Network

; to include forced sexual intercourse or any other sexual contact that's not wanted. California Law defines as physical force used to cause sexual contact are considered sexual assault money on a date gives you the right to have sex. ·Avoid excessive use of alcohol and drugs

de Lijser, Peter

357

Adolescent Sexuality and Public Policy.  

ERIC Educational Resources Information Center

Analyzed data from three national surveys of teenage sexual behavior. Defines sexually active teenager by frequency of sexual intercourse rather than one who has had intercourse. Found adolescents to be substantially less sexually active than has been previously reported. Uses finding to examine various policy decisions in areas of sex education,…

Olsen, Joseph A.; And Others

1991-01-01

358

Gynaecological conditions and sexual dysfunction  

Microsoft Academic Search

Sexuality forms an integral part of life. Consequently, serious change in a person's life influences their sexuality. The inverse is also true: disturbance in a person's sexual life can lead to problems in their daily life. Gynaecological treatment is an example of such a serious change which may affect sexual functioning and general functioning. Although the incidence of gynaecological treatment

W. C. M. Weijmar Schultz; J. Bouma; R. E. Lappöhn

1991-01-01

359

Sexual harassment proclivities in men  

Microsoft Academic Search

Three studies were conducted to develop and validate a measure of sexual harassment proclivities in males. Previous studies of sexual harassment were reviewed and a gap in the current knowledge of the psychological characteristics of sexual harassers was revealed. A possible technique for studying sexual harassment proclivities was suggested by recent research on rape proclivities. Two initial studies using this

John B. Pryor

1987-01-01

360

Sexual Harassment Law in Israel  

Microsoft Academic Search

The 1998 Israeli sexual harassment law prohibits sexual harassment as a discriminatory practice, a restriction of liberty, an offence to human dignity, a violation of every person's right to elementary respect, and an infringement of the right to privacy. Additionally, the law prohibits intimidation or retaliation that accommodates sexual harassment, referred to as ‘prejudicial treatment’.Sexual harassment and prejudicial treatment are

Orit Kamir

2005-01-01

361

Masculinities, Sexualities and Child Sexual Abuse  

Microsoft Academic Search

Empirical evidence shows that child sexual abuse is overwhelmingly a male activity in that the majority of child sex offenders are male irrespective of the sex of the children they abuse. This sex specificity raises both a sex and gender question, as well as the epistemological question of how to characterise the relationship between male offenders and this particular crime.

Annie Cossins

362

What is sexual addiction?  

PubMed

Married men labeled as sexual addicts seek help after being discovered to have had broken monogamy rules for sexual behavior through their use of masturbation, pornography, cybersex, commercial sex involvement, paraphilic pursuits, or affairs. This study analyzed the sexual patterns and dynamics of 30 men who presented to 1 clinician between 2005 and 2009. Their important differences were captured by a 6-category spectrum: (a) no sexual excess beyond breaking the spouse's restrictive rules (n = 2), (b) discovery of husband's longstanding sexual secrets (n = 5), (c) new discovery of the joys of commercial sex (n = 4), (d) the bizarre or paraphilic (n = 7), (e) alternate concept of normal masculinity (n = 5), and (f) spiraling psychological deterioration (n = 7). Only the men with a spiraling psychological deterioration-about 25% of the sample with sexual issues-could reasonably be described as having a sexual addiction. This group experienced significant psychological failures before the onset of their deterioration. Another 25% were adequately defined as paraphilic. Half of the sample was not adequately described using addiction, compulsivity, impulsivity, and relationship incapacity models. The authors discuss the implications of these findings for DSM-5 and treatment. PMID:20432125

Levine, Stephen B

2010-01-01

363

Sexual selection, germline mutation rate and sperm competition  

PubMed Central

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 benefits viability alleles expressed in condition-dependent characters. Sexual selection may increase mutational input, which in turn feeds back on sexual selection because of increased variance in viability traits. PMID:12702218

Møller, AP; Cuervo, JJ

2003-01-01

364

Sexual dimorphism and age of Mediterranean salamanders.  

PubMed

We analysed sexual size dimorphism (SSD) for two Mediterranean species of the "true" salamander clade possessing distinct life histories (Salamandra algira and Mertensiella caucasica) and equilibrated the morphometric approach to individual age by using skeletochronology. For species that have a short breeding season and live at high altitudes, such as Mediterranean amphibians, the fecundity advantage hypothesis predicts female-biased SSD to maximise reproductive success. Our results showed no SSD in either species; however, morphometric data indicated a male-biased dimorphism in limb (arm and leg) dimensions in both species when compared to body size. Limb dimorphisms are likely related to the particular mating system, which involves an amplexus during spermatophore transfer. Arm length appeared sexually dimorphic during ontogeny both in viviparous S. algira and oviparous M. caucasica. A review on SSD indicated monomorphy of body size as a common lineage-specific pattern among the "true" salamander clade, but also the common presence of other traits such as sexually dimorphic limb proportions. PMID:25497699

Reinhard, Sandy; Renner, Sandra; Kupfer, Alexander

2015-02-01

365

Sexual compatibility in Fusarium pseudograminearum (Gibberella coronicola).  

PubMed

Numerous pathogenic Fusarium species have well-characterized sexual cycles, whereas others, including the crown rot fungus F. pseudograminearum, do not. We conducted studies to elucidate the potential frequency and nature of sexual reproduction in field populations of F. pseudograminearum and developed tester strains for controlled crossings under laboratory conditions. Studies on the role of sexual recombination in the life cycle of F. pseudograminearum revealed apparently low levels of female fertility under controlled laboratory conditions, despite the observation of naturally occurring perithecia of the teleomorph Gibberella coronicola at two field sites. Female fertility levels were experimentally increased to produce female fertile tester strains using four generations of single and multi-stage crossings between sibling progeny derived from fertile laboratory crosses between field isolates collected in northeastern Australia. The production of reliable female fertile tester strains has potential applications for the construction of biological species boundaries, elucidation of the physical characters of reproductive structures, and the generation of genetic diversity via sexual recombination in F. pseudograminearum. As such, the current study is a significant advancement in the understanding of G. coronicola, allowing for future characterisation of various biological, epidemiological, and genetic parameters. PMID:18694636

Bentley, Alison R; Summerell, Brett A; Burgess, Lester W

2008-09-01

366

Sexual reproduction of human fungal pathogens.  

PubMed

We review here recent advances in our understanding of sexual reproduction in fungal pathogens that commonly infect humans, including Candida albicans, Cryptococcus neoformans/gattii, and Aspergillus fumigatus. Where appropriate or relevant, we introduce findings on other species associated with human infections. In particular, we focus on rapid advances involving genetic, genomic, and population genetic approaches that have reshaped our view of how fungal pathogens evolve. Rather than being asexual, mitotic, and largely clonal, as was thought to be prevalent as recently as a decade ago, we now appreciate that the vast majority of pathogenic fungi have retained extant sexual, or parasexual, cycles. In some examples, sexual and parasexual unions of pathogenic fungi involve closely related individuals, generating diversity in the population but with more restricted recombination than expected from fertile, sexual, outcrossing and recombining populations. In other cases, species and isolates participate in global outcrossing populations with the capacity for considerable levels of gene flow. These findings illustrate general principles of eukaryotic pathogen emergence with relevance for other fungi, parasitic eukaryotic pathogens, and both unicellular and multicellular eukaryotic organisms. PMID:25085958

Heitman, Joseph; Carter, Dee A; Dyer, Paul S; Soll, David R

2014-08-01

367

SEXUAL MISCONDUCT POLICY Case Western Reserve University  

E-print Network

1 SEXUAL MISCONDUCT POLICY Case Western Reserve University Table of Contents Page Introduction 3 Definition and Examples 4 Sexual Harassment 4 Sexual Exploitation 4 Non-Consensual Sexual Contact or Activity 5 Forced Sexual Contact or Activity 5 Non-Consensual Sexual Intercourse 5 Forced Sexual Intercourse

Yang, Sichun

368

Sexual behavior and its pheromonal regulation in ascosporogenous yeasts.  

PubMed

We reviewed our investigations on sexual behaviors and interactions including sexual cell agglutination and pheromone action mainly in non-conventional yeasts, Hansenula anomala, H. wingei, Pichia amethionina, P. heedi, P. opuntiae, Saccharomyces kluyveri, S. globsus, S. exiguus, Saccharomycodes ludwigii. The techniques and genetic models including the cassette model and alpha 1-alpha 2 hypothesis which had been developed largely in S. cerevisiae were applicable to these yeasts in principle. The sexual agglutination was distinctly species-specific while sex pheromones were cross-reactive beyond species' barriers. The successful induction of heterothallic strains from homothallic strains in S. exiguus by mutagenesis enabled to the subsequent biochemical and genetical analysis of sexual behavior in the yeast. The phylogenetic consideration on sex differentiation is also included. PMID:2651648

Yoshida, K; Hisatomi, T; Yanagishima, N

1989-01-01

369

Reproductive strategy, sexual development and attraction to facial characteristics.  

PubMed

Sexual reproduction strategies vary both between and within species in the level of investment in offspring. Life-history theories suggest that the rate of sexual maturation is critically linked to reproductive strategy, with high investment being associated with few offspring and delayed maturation. For humans, age of puberty and age of first sex are two developmental milestones that have been associated with reproductive strategies. Stress during early development can retard or accelerate sexual maturation and reproduction. Early age of menarche is associated with absence of younger siblings, absence of a father figure during early life and increased weight. Father absence during early life is also associated with early marriage, pregnancy and divorce. Choice of partner characteristics is critical to successful implementation of sexual strategies. It has been suggested that sexually dimorphic traits (including those evident in the face) signal high-quality immune function and reproductive status. Masculinity in males has also been associated with low investment in mate and offspring. Thus, women's reproductive strategy should be matched to the probability of male investment, hence to male masculinity. Our review leads us to predict associations between the rate of sexual maturation and adult preferences for facial characteristics (enhanced sexual dimorphism and attractiveness). We find for men, engaging in sex at an early age is related to an increased preference for feminized female faces. Similarly, for women, the earlier the age of first sex the greater the preference for masculinity in opposite-sex faces. When we controlled sexual dimorphism in male faces, the speed of sexual development in women was not associated with differences in preference for male facial attractiveness. These developmental influences on partner choice were not mediated by self-rated attractiveness or parental relationships. We conclude that individuals assort in preferences based on the rapidity of their sexual development. Fast developing individuals prefer opposite-sex partners with an increased level of sexually dimorphic facial characteristics. PMID:17118929

Cornwell, R Elisabeth; Law Smith, Miriam J; Boothroyd, Lynda G; Moore, Fhionna R; Davis, Hasker P; Stirrat, Michael; Tiddeman, Bernard; Perrett, David I

2006-12-29

370

The pursuit of sexual pleasure  

Microsoft Academic Search

While people engage in sexual activities for a variety of reasons, one primary motivation is pleasure. Rather than disentangle\\u000a the various complications of human sexuality, this paper will focus on sexual pleasure. We begin with definitions of sex and\\u000a sexuality, and a consideration of the nature of sexual pleasure. To this end, we will discuss a wide variety of activities

B. J. Rye; Glenn J. Meaney

2007-01-01

371

Effect of tropical storms on sexual and asexual reproduction in coral Pocillopora verrucosa subpopulations in the Gulf of California  

NASA Astrophysics Data System (ADS)

Pocillopora verrucosa is a branching, reef-building coral, and a simultaneous hermaphrodite that reproduces sexually and asexually by fragmentation. In the Gulf of California, local P. verrucosa populations have mixed modes of reproduction which vary in frequency by site. Sexual and asexual reproductions were assessed using multi-locus genotypes deriving from six microsatellite loci at every location. Clone frequencies varied from 0.30 at Loreto to 0.96 in the San Lorenzo Channel. Isla Espíritu Santo and the San Lorenzo Channel were mostly asexual subpopulations, presented the lowest genotypic richness ( N g / N = 0.1-0.12) and genotypic diversity ( G o / G e = 0.04), and were dominated by one or two multi-loci genotypes ( G o / N g = 0.35-0.45). Loreto, El Portugués, and Cabo Pulmo were mostly sexual with high Ng/ N (0.80-0.74) and G o / G e (0.52-0.58) and did not show domination by a single multi-locus genotype ( G o / N g = 0.70-0.74). There was a significant relationship ( P < 0.05) between tropical storm frequency and the genotypic indexes of richness and diversity modeling an inverted U-shape, which indicates that the sites where storm frequencies were the highest had mostly clonal populations; sites exposed to intermediate or low storm frequencies had mostly sexual populations. The study included a restored area (San Lorenzo Channel) where genotypic analyses showed a high level of clonality similar to natural conditions occurring in a nearby subpopulation (Isla Espíritu Santo), which demonstrates the low natural genetic diversity of the area. This study showed that a species with mixed reproduction modes has different maintenance strategies at a regional and even local level among populations indicating the crucial role that storms play in population structure.

Aranceta-Garza, F.; Balart, E. F.; Reyes-Bonilla, H.; Cruz-Hernández, P.

2012-12-01

372

Reproducing Natural Spider Silks’ Copolymer Behavior in Synthetic Silk Mimics  

PubMed Central

Dragline silk from orb-weaving spiders is a copolymer of two large proteins, major ampullate spidroin 1 (MaSp1) and 2 (MaSp2). The ratio of these proteins is known to have a large variation across different species of orb-weaving spiders. NMR results from gland material of two different species of spiders, N. clavipes and A. aurantia, indicates that MaSp1 proteins are more easily formed into ?-sheet nanostructures, while MaSp2 proteins form random coil and helical structures. To test if this behavior of natural silk proteins could be reproduced by recombinantly produced spider silk mimic protein, recombinant MaSp1/MaSp2 mixed fibers as well as chimeric silk fibers from MaSp1 and MaSp2 sequences in a single protein were produced based on the variable ratio and conserved motifs of MaSp1 and MaSp2 in native silk fiber. Mechanical properties, solid-state NMR, and XRD results of tested synthetic fibers indicate the differing roles of MaSp1 and MaSp2 in the fiber and verify the importance of postspin stretching treatment in helping the fiber to form the proper spatial structure. PMID:23110450

An, Bo; Jenkins, Janelle E.; Sampath, Sujatha; Holland, Gregory P.; Hinman, Mike; Yarger, Jeffery L.; Lewis, Randolph

2012-01-01

373

Sexual Dimorphism in Primate Aerobic Capacity: A Phylogenetic Test  

PubMed Central

Male intrasexual competition should favour increased male physical prowess. This should in turn result in greater aerobic capacity in males than in females (i.e., sexual dimorphism), and a correlation between sexual dimorphism in aerobic capacity and the strength of sexual selection among species. However, physiological scaling laws predict that aerobic capacity should be lower per unit body mass in larger than in smaller animals, potentially reducing or reversing the sex difference and its association with measures of sexual selection. We used measures of hematocrit and red blood cell (RBC) counts from 45 species of primates to test four predictions related to sexual selection and body mass: (i) on average, males should have higher aerobic capacity than females, (ii) aerobic capacity should be higher in adult than juvenile males, (iii) aerobic capacity should increase with increasing sexual selection, but also that (iv) measures of aerobic capacity should covary negatively with body mass. For the first two predictions we used a phylogenetic paired t-test developed for this study. We found support for predictions (i) and (ii). For prediction (iii), however, we found a negative correlation between the degree of sexual selection and aerobic capacity, which was opposite to our prediction. Prediction (iv) was generally supported. We also investigated whether substrate use, basal metabolic rate, and agility influenced physiological measures of oxygen transport, but we found only weak evidence for a correlation between RBC count and agility. PMID:20406346

Lindenfors, Patrik; Revell, Liam J.; Nunn, Charles L.

2010-01-01

374

Sexual Esteem, Sexual Satisfaction, and Sexual Behavior Among People with Physical Disability  

Microsoft Academic Search

This study investigated the association between the severity and duration of physical disability and sexual esteem, sexual depression, sexual satisfaction, and the frequency of sexual behavior. A total of 1,196 participants completed the study. There were 748 participants (367 males, 381 females) who had a physical disability and 448 participants (171 males, 277 females) who were able-bodied. The age range

Marita P. McCabe; George Taleporos

2003-01-01

375

Sexual scripts and sexual risk behaviors among black heterosexual men: development of the sexual scripts scale.  

PubMed

Sexual scripts are widely shared gender and culture-specific guides for sexual behavior with important implications for HIV prevention. Although several qualitative studies document how sexual scripts may influence sexual risk behaviors, quantitative investigations of sexual scripts in the context of sexual risk are rare. This mixed methods study involved the qualitative development and quantitative testing of the Sexual Scripts Scale (SSS). Study 1 included qualitative semi-structured interviews with 30 Black heterosexual men about sexual experiences with main and casual sex partners to develop the SSS. Study 2 included a quantitative test of the SSS with 526 predominantly low-income Black heterosexual men. A factor analysis of the SSS resulted in a 34-item, seven-factor solution that explained 68 % of the variance. The subscales and coefficient alphas were: Romantic Intimacy Scripts (? = .86), Condom Scripts (? = .82), Alcohol Scripts (? = .83), Sexual Initiation Scripts (? = .79), Media Sexual Socialization Scripts (? = .84), Marijuana Scripts (? = .85), and Sexual Experimentation Scripts (? = .84). Among men who reported a main partner (n = 401), higher Alcohol Scripts, Media Sexual Socialization Scripts, and Marijuana Scripts scores, and lower Condom Scripts scores were related to more sexual risk behavior. Among men who reported at least one casual partner (n = 238), higher Romantic Intimacy Scripts, Sexual Initiation Scripts, and Media Sexual Socialization Scripts, and lower Condom Scripts scores were related to higher sexual risk. The SSS may have considerable utility for future research on Black heterosexual men's HIV risk. PMID:24311105

Bowleg, Lisa; Burkholder, Gary J; Noar, Seth M; Teti, Michelle; Malebranche, David J; Tschann, Jeanne M

2015-04-01

376

Sexual Behavior, Sexual Knowledge, and Sexual Attitudes of Emerging Adult Women: Implications for Working with Families  

ERIC Educational Resources Information Center

The purpose of this study was twofold: first, to examine the sexual behavior of emerging adult women in relation to their sexual knowledge, sexual attitudes, and perceptions of their parents' sexual attitudes; and second, to discuss the implications of this research in working with young adult women. Three hundred and sixty-four college-age women…

Byno, Lucy H.; Mullis, Ronald L.; Mullis, Ann K.

2009-01-01

377

Reproducing kernel element method Part III: Generalized enrichment and applications  

E-print Network

Reproducing kernel element method Part III: Generalized enrichment and applications Hongsheng Lu finite element methods, the construction proposed here has more flexibility and only needs minimal degrees of freedom. The optimal element with high reproducing capacity and overall minimal degrees

Li, Shaofan

378

Wave propagation software, computational science, and reproducible research  

E-print Network

Wave propagation software, computational science, and reproducible research Randall J. Le for more reproducibility in computational research. Sample applications discussed include medical on the topic of software development and its relation to mathematics, and on computational science

LeVeque, Randy

379

10 CFR 95.43 - Authority to reproduce.  

Code of Federal Regulations, 2012 CFR

...discourages, or detects the unauthorized reproduction of classified documents is encouraged. (b) Unless restricted by the CSA, Secret and Confidential documents may be reproduced. Reproduced copies of classified documents are subject to the same...

2012-01-01

380

10 CFR 95.43 - Authority to reproduce.  

Code of Federal Regulations, 2013 CFR

...discourages, or detects the unauthorized reproduction of classified documents is encouraged. (b) Unless restricted by the CSA, Secret and Confidential documents may be reproduced. Reproduced copies of classified documents are subject to the same...

2013-01-01

381

10 CFR 95.43 - Authority to reproduce.  

Code of Federal Regulations, 2011 CFR

...discourages, or detects the unauthorized reproduction of classified documents is encouraged. (b) Unless restricted by the CSA, Secret and Confidential documents may be reproduced. Reproduced copies of classified documents are subject to the same...

2011-01-01

382

Male-limited evolution suggests no extant intralocus sexual conflict over the sexually dimorphic cuticular hydrocarbons of Drosophila melanogaster.  

PubMed

Sexually dimorphic traits are likely to have evolved through sexually antagonistic selection. However, recent empirical data suggest that intralocus sexual conflict often persists, even when traits have diverged between males and females. This implies that evolved dimorphism is often incomplete in resolving intralocus conflict, providing a mechanism for the maintenance of genetic variance in fitness-related traits. We used experimental evolution in Drosophila melanogaster to directly test for ongoing conflict over a suite of sexually dimorphic cuticular hydrocarbons (CHCs) that are likely targets of sex-specific selection. Using a set of experimental populations in which the transmission of genetic material had been restricted to males for 82 generations, we show that CHCs did not evolve, providing experimental evidence for the absence of current intralocus sexual conflict over these traits. The absence of ongoing conflict could indicate that CHCs have never been the target of sexually antagonistic selection, although this would require the existing dimorphism to have evolved via completely sexlinked mutations or as a result of former, but now absent, pleiotropic effects of the underlying loci on another trait under sexually antagonistic selection. An alternative interpretation, and which we believe to be more likely, is that the extensive CHC sexual dimorphism is the result of past intralocus sexual conflict that has been fully resolved, implying that these traits have evolved genetic independence between the sexes and that genetic variation in them is therefore maintained by alternative mechanisms. This latter interpretation is consistent with the known roles of CHCs in sexual communication in this species and with previous studies suggesting the genetic independence of CHCs between males and females. Nevertheless, direct estimates of sexually antagonistic selection will be important to fully resolve these alternatives. PMID:22227931

Bedhomme, Stéphanie; Chippindale, Adam K; Prasad, N G; Delcourt, Matthieu; Abbott, Jessica K; Mallet, Martin A; Rundle, Howard D

2011-12-01

383

Reproducible conductance fluctuations in macroscopic Anderson insulators  

SciTech Connect

We study theoretically the reproducible magnetoconductance fluctuations in macroscopic Anderson insulators where complex random interferences yield localization at a scale {xi} larger than the elastic mean free path {ital l}. Based on the hypothesis of large ergodic quantum fluctuations of {xi} when a flux quantum is applied through an area {xi}{sup 2}, we show that the normalized magnetoconductance fluctuations {delta}{ital G}{sub tot}/{ital G}{sub tot} is ({xi}{sub {ital p}}{sup {ital D}}/{Omega}{sub {ital e}{ital f}{ital f}}){sup 1/2} for ergodic field changes {Delta}{ital B}{similar to}{phi}{sub 0}/{xi}{sup 2}, where {xi}{sub {ital p}} is a percolation correlation length which approaches macroscopic length scales at very low temperatures, and {Omega}{sub {ital e}{ital f}{ital f}} is an effective volume for th classical self-averaging of the fluctuations.

Feng, S. (Department of Physics, University of California, Los Angeles, CA (USA)); Pichard, J. (Service de Physique du Solide et de Resonance Magnetique, Commissariat a l'Energie Atomique Saclay, 91191 Gif-sur-Yvette CEDEX, France (FR))

1991-08-05

384

Reproducibility of binary-mixture toxicity studies.  

PubMed

Binary-mixture studies often are conducted with the aim of elucidating the effect of one specific chemical on the biological action of another. The results can be interpreted in relation to reference models by the use of response-surface analyses and isobolograms. The amount of data needed for these analyses is, however, extensive, and the experiments therefore rarely are repeated. In the present study, we investigate the reproducibility of isobole shapes of binary-mixture toxicity experiments in terms of deviation from the reference model of concentration addition (CA), dose-level dependence, and isobole asymmetry. We use data from four herbicide mixtures tested in three to five independent experiments on the aquatic test plant Lemna minor and the terrestrial plant Tripleurospermum inodorum. The results showed that the variation both within and among experiments was approximately half the size for the aquatic test system compared to the terrestrial system. As a consequence, a consistent deviation from CA could be obtained in three of four herbicide mixtures for L. minor, whereas this was only the case for one or two of the herbicide mixtures tested on T. inodorum. For one mixture on T. inodorum, both CA synergism and antagonism were detected. Dose-dependent effects could not be repeated consistently, just as the asymmetry found in some isoboles could not. The study emphasizes the importance of repeating mixture toxicity experiments, especially for test systems with large variability, and using caution when drawing biological conclusions from the test results. PMID:17269472

Cedergreen, Nina; Kudsk, Per; Mathiassen, Solvejg Kopp; Sørensen, Helle; Streibig, Jens Carl

2007-01-01

385

HarassmentNO What is Sexual Assault as defined in the UCSC Policy on Sexual Assault?  

E-print Network

HarassmentNO What is Sexual Assault as defined in the UCSC Policy on Sexual Assault? Sexual assault sexual acts, and sexual ba ery. Sexual ba ery is the touching of an in mate part of a man or a women without her/his consent. " " What is Sexual Harassment as defined in the UC Policy on Sexual Harassment

Lee, Herbie

386

MSU Resource Guide on Sexual Assault as a Form of Sexual Harassment  

E-print Network

MSU Resource Guide on Sexual Assault as a Form of Sexual Harassment MSU Statement Regarding Sexual Assault as a form of Sexual Harassment Michigan State University is committed to maintaining. Sexual assault is a form of sexual harassment. The MSU Sexual Harassment Policy (www.inclusion.msu.edu/files/Sexual_Harassment

387

Multidimensional Characterization of Sexual Minority Adolescents’ Sexual Safety Strategies  

PubMed Central

Young adults have high rates of sexually transmitted infections (STIs). Sexual minority youths’ risk for STIs, including HIV, is as high as or higher than sexual majority peers’. Sexual safety, while often treated as a single behavior such as condom use, can be best conceptualized as the result of multiple factors. We used latent class analysis to identify profiles based on ever-used sexual safety strategies and lifetime number of partners among 425 self-identified LGBTQ youth aged 14-19. Data collection took place anonymously online. We identified four specific subgroup profiles for males and three for females, with each subgroup representing a different level and type of sexual safety. Profiles differed from each other in terms of age and outness for males, and in outness, personal homonegativity, and amount of education received about sexual/romantic relationships for females. Youths’ sexual safety profiles have practice implications for sexuality educators, health care professionals, and parents. PMID:24011111

Masters, N. Tatiana; Beadnell, Blair; Morrison, Diane M.; Hoppe, Marilyn J.; Wells, Elizabeth A.

2013-01-01

388

Multidimensional characterization of sexual minority adolescents' sexual safety strategies.  

PubMed

Young adults have high rates of sexually transmitted infections (STIs). Sexual minority youths' risk for STIs, including HIV, is as high as or higher than sexual majority peers'. Sexual safety, while often treated as a single behavior such as condom use, can be best conceptualized as the result of multiple factors. We used latent class analysis to identify profiles based on ever-used sexual safety strategies and lifetime number of partners among 425 self-identified LGBTQ youth aged 14-19. Data collection took place anonymously online. We identified four specific subgroup profiles for males and three for females, with each subgroup representing a different level and type of sexual safety. Profiles differed from each other in terms of age and outness for males, and in outness, personal homonegativity, and amount of education received about sexual/romantic relationships for females. Youths' sexual safety profiles have practice implications for sexuality educators, health care professionals, and parents. PMID:24011111

Masters, N Tatiana; Beadnell, Blair; Morrison, Diane M; Hoppe, Marilyn J; Wells, Elizabeth A

2013-10-01

389

Sexual Orientation (For Parents)  

MedlinePLUS

... than those who hadn't. Back Continue How Parents Might Feel Adolescence is a time of transition not just for teens, but for their parents too. Many parents face their adolescent's emerging sexuality ...

390

Sexually Transmitted Diseases  

MedlinePLUS

Sexually transmitted diseases (STDs) are infections that you can get from having sex with someone who has the infection. The causes ... is no cure. Sometimes medicines can keep the disease under control. Correct usage of latex condoms greatly ...

391

Men and Sexual Trauma  

MedlinePLUS

... in symptoms of adolescents reporting sexual assault. Social Psychiatry & Psychiatric Epidemiology, 33, 111-117. Etherington, K. (1995). ... Journal of the American Academy of Child & Adolescent Psychiatry, 36, 323-329. Gordon, M. (1990). Males and ...

392

Prevalence of Sexual Dysfunctions  

PubMed Central

Ten years of research that has provided data regarding the prevalence of sexual dysfunctions is reviewed. A thorough review of the literature identified 52 studies that have been published in the 10 years since an earlier review by Spector and Carey (1990). Community samples indicate a current prevalence of 0 - 3% for male orgasmic disorder, 0 - 5% for erectile disorder, and 0 - 3% for male hypoactive sexual desire disorder. Pooling current and 1-year figures provides community prevalence estimates of 7 - 10% for female orgasmic disorder and 4 - 5% for premature ejaculation. Stable community estimates of the current prevalence for the other sexual dysfunctions remain unavailable. Prevalence estimates obtained from primary care and sexuality clinic samples are characteristically higher. Although a relatively large number of studies have been conducted since Spector and Carey’s (1990) review, the lack of methodological rigor of many studies limits the confidence that can be placed in these findings. PMID:11329727

Simons, Jeffrey; Carey, Michael P.

2008-01-01

393

Child abuse - sexual  

MedlinePLUS

... child sexual abuse occurs, because it is more secret than physical abuse. Children are often scared to ... Prevention involves teaching children never to keep secrets and ... begin this work at home. Most schools now have programs to teach ...

394

Sexual Health and Reproduction  

NSDL National Science Digital Library

This activity provides questions and Web sites to guide student investigation of birth control methods, fetal development, risks of alcohol and smoking during pregnancy, changes during puberty, and HIV/AIDS and other sexually transmitted diseases.

Ingrid Waldron

395

Meiosis and Sexual Reproduction  

NSDL National Science Digital Library

This lesson describes how meiosis makes sexual reproduction possible. Specifically, meiosis produces haploid cells and allows for genetic variation. Key terms in this lesson are hyperlinked so students can easily find definitions to new words.

2012-06-04

396

Women and sexual problems  

MedlinePLUS

... sex. Illnesses like cancer, bladder or bowel diseases, arthritis, and headaches may cause sexual problems. Some medicines can cause problems with sex. Medicine for blood pressure, depression, and chemotherapy can decrease your sex drive or make it hard to ...

397

Sexual Abuse of Children.  

ERIC Educational Resources Information Center

Canadian reports and legislation are reviewed to highlight the school's role in prevention and reporting of suspicions of child sexual abuse. The vulnerability of handicapped children and child pornography are two areas of victimization emphasized. (Author/DB)

Csapo, Marg

1988-01-01

398

Sexuality and Dementia  

MedlinePLUS

... Awards Program Development PolicyDigest Newsletter Caregiver Connect SF Bay Area Services Family Care Navigator Research Registry Support ... recent conference of the Caregiver Resource Centers of California, the keynote presentation was on sexuality and intimacy. ...

399

Wired on Steroids: Sexual Differentiation of the Brain and Its Role in the Expression of Sexual Partner Preferences  

PubMed Central

The preference to seek out a sexual partner of the opposite sex is robust and ensures reproduction and survival of the species. Development of female-directed partner preference in the male is dependent on exposure of the developing brain to gonadal steroids synthesized during critical periods of sexual differentiation of the central nervous system. In the absence of androgen exposure, a male-directed partner preference develops. The development and expression of sexual partner preference has been extensively studied in rat, ferret, and sheep model systems. From these models it is clear that gonadal testosterone, often through estrogenic metabolites, cause both masculinization and defeminization of behavior during critical periods of brain development. Changes in the steroid environment during these critical periods result in atypical sexual partner preference. In this manuscript, we review the major findings which support the hypothesis that the organizational actions of sex steroids are responsible for sexual differentiation of sexual partner preferences in select non-human species. We also explore how this information has helped to frame our understanding of the biological influences on human sexual orientation and gender identity. PMID:22654808

Alexander, Brenda M.; Skinner, Donal C.; Roselli, Charles E.

2011-01-01

400

The Implications of Sexual Narcissism for Sexual and Marital Satisfaction  

PubMed Central

There is theoretical reason to believe narcissism is associated with a number of sexual behaviors and outcomes that affect both sexual and relationship satisfaction. Nevertheless, research on the association between personality and behavior demonstrates that personality traits, such as narcissism, only predict behavior in domains that activate the components of the personality system. Given that global assessments of narcissism do not capture the extent to which the components of narcissism are activated in the sexual domain, we examined the extent to which the facets of a domain-specific measure of sexual narcissism accounted for the trajectories of own and partner sexual and marital satisfaction over the first five years of 120 new marriages. Three of the four facets of sexual narcissism (sexual exploitation, sexual entitlement, and low sexual empathy) were negatively associated with both trajectories. The fourth facet (sexual skill) was positively associated with both trajectories. Notably, sexual satisfaction mediated the effect of every facet of sexual narcissism on marital satisfaction. A global assessment of narcissism was not associated with either trajectory of satisfaction. These findings highlight (1) the importance of narcissistic tendencies for sexual processes, (2) the benefits of using domain-specific measures of personality in research on sexual behavior, and (3) the importance of examining the implications of the specific facets of personality constructs. PMID:23297145

McNulty, James K.; Widman, Laura

2013-01-01

401

Sexual dysfunctions in depression  

Microsoft Academic Search

The incidence of sexual dysfunctions in a group of 51 drug-free depressed patients and in age- and sex-matched controls was studied. Three groups of sexual dysfunction were assessed: alterations of libido, genital symptoms, and menstrual irregularities. The Beck Rating Scale for Depression, the Eysenck Personality Inventory (EPI), and the State-Trait Anxiety Inventory were completed on each participant. Depressed patients obtained

Roy J. Mathew; Maxine L. Weinman

1982-01-01

402

Sexual Dysfunction Following Vulvectomy  

Microsoft Academic Search

Objective. This is a pilot study to evaluate sexual dysfunction in women after vulvectomy.Methods. An 88-question survey was used to assess body image and the DSM IV criteria for sexual dysfunction on women who had undergone vulvectomy.Results. Forty-seven women agreed to participate in the study and 41 women (87%) returned the survey. There was a significant alteration of body image

Michael S. Green; R. Wendel Naumann; Mollie Elliot; James B. Hall; Robert V. Higgins; Jared H. Grigsby

2000-01-01

403

The Sexual Domain of Identity: Sexual Statuses of Identity in Relation to Psychosocial Sexual Health  

Microsoft Academic Search

Sexual identity has been substantially underinvestigated relative to other aspects of identity. The purpose of this study was to document the relationship between sexual psychosocial maturity, positive sexual self-concepts, and effective sexual decision-making\\/coping styles with the identity processes that college students choose to use in defining their sexual self. Participants in the study were 275 undergraduate male and female students

Sally L. Archer; Jeremy A. Grey

2009-01-01

404

RAPID COMMUNICATION VARROA JACOBSONI DOES REPRODUCE IN WORKER  

E-print Network

) reported that Varroa jacobsoni greatly prefers drone over worker brood, and only reproduces in the drone brood of Apis cerana colonies in Sri Lanka and Indonesia. In Apis mellifera the mites also prefer drone cells, but can reproduce effectively in both worker and drone cells. The capacity to reproduce in worker

Paris-Sud XI, Université de

405

A quasispecies approach to the evolution of sexual replication in unicellular organisms  

Microsoft Academic Search

This study develops a simplified model describing the evolutionary dynamics of a population composed of obligate sexually\\u000a and asexually reproducing, unicellular organisms. The model assumes that the organisms have diploid genomes consisting of\\u000a two chromosomes, and that the sexual organisms replicate by first dividing into haploid intermediates, which then combine\\u000a with other haploids, followed by the normal mitotic division of

Emmanuel Tannenbaum; José F. Fontanari

2008-01-01

406

Maturation costs affect maturation timing: sexual reproduction in a heterogonic hydra  

Microsoft Academic Search

If maturation is more costly for females, they may need more distinct environmental cues to induce sexual reproduction than\\u000a males. We verified this hypothesis by comparing the indirect costs of maturation to males and females of the heterogonic Hydra oligactis, reproducing both asexually and sexually. The laboratory experiments revealed that males mature 2 weeks earlier than the\\u000a first females at falling

Anita Kaliszewicz; Agnieszka Lipi?ska

407

Asexual reproduction induces a rapid and permanent loss of sexual reproduction capacity in the rice fungal pathogen Magnaporthe oryzae: results of in vitro experimental evolution assays  

PubMed Central

Background Sexual reproduction is common in eukaryotic microorganisms, with few species reproducing exclusively asexually. However, in some organisms, such as fungi, asexual reproduction alternates with episodic sexual reproduction events. Fungi are thus appropriate organisms for studies of the reasons for the selection of sexuality or clonality and of the mechanisms underlying this selection. Magnaporthe oryzae, an Ascomycete causing blast disease on rice, reproduces mostly asexually in natura. Sexual reproduction is possible in vitro and requires (i) two strains of opposite mating types including (ii) at least one female-fertile strain (i.e. a strain able to produce perithecia, the female organs in which meiosis occurs). Female-fertile strains are found only in limited areas of Asia, in which evidence for contemporary recombination has recently been obtained. We induced the forced evolution of four Chinese female-fertile strains in vitro by the weekly transfer of asexual spores (conidia) between Petri dishes. We aimed to determine whether female fertility was rapidly lost in the absence of sexual reproduction and whether this loss was controlled genetically or epigenetically. Results All the strains became female-sterile after 10 to 19 rounds of selection under asexual conditions. As no single-spore isolation was carried out, the observed decrease in the production of perithecia reflected the emergence and the invasion of female-sterile mutants. The female-sterile phenotype segregated in the offspring of crosses between female-sterile evolved strains and female-fertile wild-type strains. This segregation was maintained in the second generation in backcrosses. Female-sterile evolved strains were subjected to several stresses, but none induced the restoration of female fertility. This loss of fertility was therefore probably due to genetic rather than epigenetic mechanisms. In competition experiments, female-sterile mutants produced similar numbers of viable conidia to wild-type strains, but released them more efficiently. This advantage may account for the invasion of our populations by female-sterile mutants. Conclusions We show for the first time that, in the absence of sexual reproduction, female-sterile mutants of M. oryzae rice strains can arise and increase in abundance in asexual generations. This change in phenotype was frequent and probably caused by mutation. These results suggest that female fertility may have been lost rapidly during the dispersion of the fungus from Asia to the rest of the world. PMID:22458778

2012-01-01

408

UCSC Policy on Sexual Assault University of California Policy on Sexual Harassment  

E-print Network

UCSC Policy on Sexual Assault University of California Policy on Sexual Harassment and Procedures for Reporting Sexual Harassment and Sexual Assault December 1994 · Amended January 2005 · Amended August 2011 ...............................................................1 I. UCSC Policy on Sexual Assault

Lee, Herbie

409

Reproducibility and utility of dune luminescence chronologies  

NASA Astrophysics Data System (ADS)

Optically stimulated luminescence (OSL) dating of dune deposits has increasingly been used as a tool to investigate the response of aeolian systems to environmental change. Amalgamation of individual dune accumulation chronologies has been employed in order to distinguish regional from local geomorphic responses to change. However, advances in dating have produced chronologies of increasing complexity. In particular, questions regarding the interpretation of dune ages have been raised, including over the most appropriate method to evaluate the significance of suites of OSL ages when local 'noisy' and discontinuous records are combined. In this paper, these issues are reviewed and the reproducibility of dune chronologies is assessed. OSL ages from two cores sampled from the same dune in the northeast Rub' al Khali, United Arab Emirates, are presented and compared, alongside an analysis of previously published dune ages dated to within the last 30 ka. Distinct periods of aeolian activity and preservation are identified, which can be tied to regional climatic and environmental changes. This case study is used to address fundamental questions that are persistently asked of dune dating studies, including the appropriate spatial scale over which to infer environmental and climatic change based on dune chronologies, whether chronological hiatuses can be interpreted, how to most appropriately combine and display datasets, and the relationship between geomorphic and palaeoclimatic signals. Chronological profiles reflect localised responses to environmental variability and climatic forcing, and amalgamation of datasets, with consideration of sampling resolution, is required; otherwise local factors are always likely to dominate. Using net accumulation rates to display ages may provide an informative approach of analysing and presenting dune OSL chronologies less susceptible to biases resulting from insufficient sampling resolution.

Leighton, Carly L.; Thomas, David S. G.; Bailey, Richard M.

2014-02-01

410

Sexual selection targets cetacean pelvic bones.  

PubMed

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 that 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) tend to evolve larger penises and pelvic bones compared to their body length, and (2) pelvic bone shape has diverged more 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

Dines, James P; Otárola-Castillo, Erik; Ralph, Peter; Alas, Jesse; Daley, Timothy; Smith, Andrew D; Dean, Matthew D

2014-11-01

411

Sexual coercion and the misperception of sexual intent?  

PubMed Central

Misperceiving a woman’s platonic interest as sexual interest has been implicated in a sexual bargaining process that leads to sexual coercion. This paper provides a comprehensive review of sexual misperception, including gender differences in perception of women’s sexual intent, the relationship between sexual coercion and misperception, and situational factors that increase the risk that sexual misperception will occur. Compared to women, men consistently perceive a greater degree of sexual intent in women’s behavior. However, there is evidence to suggest that this gender effect may be driven largely by a sub-group of men who are particularly prone to perceive sexual intent in women’s behavior, such as sexually coercive men and men who endorse sex-role stereotypes. Situational factors, such as alcohol use by the man or woman, provocative clothing, and dating behaviors (e.g., initiating the date or making eye contact), are all associated with increased estimates of women’s sexual interest. We also critique the current measurement strategies and introduce a model of perception that more closely maps on to important theoretical questions in this area. A clearer understanding of sexual perception errors and the etiology of these errors may serve to guide sexual-assault prevention programs toward more effective strategies. PMID:17462798

Farris, Coreen; Treat, Teresa A.; Viken, Richard J.; McFall, Richard M.

2010-01-01

412

Body Image, Relationships and Sexuality After Amputation  

MedlinePLUS

... honest conversations like these. Sexuality We are all sexual beings. This term refers to all the ways ... feelings and emotions. Our whole body responds to sexual attraction. Sexuality includes feelings of arousal (expressed by ...

413

SEXUAL HARASSMENT POLICY Office of Equal Opportunity  

E-print Network

SEXUAL HARASSMENT POLICY Office of Equal Opportunity Purpose: To establish uniform guidelines pertaining to sexual harassment. Revised: April 2014 Applicability: Sexual Harassment is a form and community members). This policy is summarized in the University's Sexual Misconduct/Assault Policy

Dennett, Daniel

414

Sexual Assault Prevention Workshop Final Report  

E-print Network

WGS 296A Sexual Assault Prevention Workshop Final Report Recommendations for Improving Sexual 14, 2009 #12;TABLE OF CONTENTS PART ONE: SEXUAL ASSAULT AT WASHINGTON AND LEE UNIVERSITY (W&L) ..............................1 CONTRIBUTING FACTORS FOR COLLEGE SEXUAL ASSAULT

Marsh, David

415

Sexual abuse in children - what to know  

MedlinePLUS

Sexual abuse - children ... boys are sexually abused before they turn 18. Sexual abuse of children is any activity that the ... anus or vagina Tongue kissing Oral sex Intercourse Sexual abuse can also happen without physical contact, such ...

416

Semiautomated, Reproducible Batch Processing of Soy  

NASA Technical Reports Server (NTRS)

A computer-controlled apparatus processes batches of soybeans into one or more of a variety of food products, under conditions that can be chosen by the user and reproduced from batch to batch. Examples of products include soy milk, tofu, okara (an insoluble protein and fiber byproduct of soy milk), and whey. Most processing steps take place without intervention by the user. This apparatus was developed for use in research on processing of soy. It is also a prototype of other soy-processing apparatuses for research, industrial, and home use. Prior soy-processing equipment includes household devices that automatically produce soy milk but do not automatically produce tofu. The designs of prior soy-processing equipment require users to manually transfer intermediate solid soy products and to press them manually and, hence, under conditions that are not consistent from batch to batch. Prior designs do not afford choices of processing conditions: Users cannot use previously developed soy-processing equipment to investigate the effects of variations of techniques used to produce soy milk (e.g., cold grinding, hot grinding, and pre-cook blanching) and of such process parameters as cooking times and temperatures, grinding times, soaking times and temperatures, rinsing conditions, and sizes of particles generated by grinding. In contrast, the present apparatus is amenable to such investigations. The apparatus (see figure) includes a processing tank and a jacketed holding or coagulation tank. The processing tank can be capped by either of two different heads and can contain either of two different insertable mesh baskets. The first head includes a grinding blade and heating elements. The second head includes an automated press piston. One mesh basket, designated the okara basket, has oblong holes with a size equivalent to about 40 mesh [40 openings per inch (.16 openings per centimeter)]. The second mesh basket, designated the tofu basket, has holes of 70 mesh [70 openings per inch (.28 openings per centimeter)] and is used in conjunction with the press-piston head. Supporting equipment includes a soy-milk heat exchanger for maintaining selected coagulation temperatures, a filter system for separating okara from other particulate matter and from soy milk, two pumps, and various thermocouples, flowmeters, level indicators, pressure sensors, valves, tubes, and sample ports

Thoerne, Mary; Byford, Ivan W.; Chastain, Jack W.; Swango, Beverly E.

2005-01-01

417

Examination of boldness traits in sexual and asexual mollies ( Poecilia latipinna , P. formosa )  

Microsoft Academic Search

Considering the high costs of sexual reproduction (e.g., the production of males), its maintenance and predominance throughout\\u000a the Animal Kingdom remain elusive. Especially the mechanisms allowing for a stable coexistence of closely related sexual and\\u000a asexual species are still subject to a lively debate. Asexuals should rapidly outnumber sexuals due to higher population growth\\u000a rates, unless they face some disadvantages.

Kristin Scharnweber; Martin Plath; Michael Tobler

418

Is sexual monomorphism a predictor of polygynandry? Evidence from a social mammal, the collared peccary  

Microsoft Academic Search

Sexual dimorphism is common in polygynous species, and there is clear evidence that both intra-sexual competition and female\\u000a preferences can drive the evolution of large body size in males. In contrast, sexual monomorphism is often argued to reflect\\u000a a relaxation of male mate competition or an intensification of resource competition among females. Alternatively, it might\\u000a imply opportunities for females to

Jennifer D. Cooper; Peter M. Waser; Eric C. Hellgren; Timothy M. Gabor; J. A. DeWoody

2011-01-01

419

Is Hippolyte williamsi gonochoric or hermaphroditic? A multi-approach study and a review of sexual systems in Hippolyte shrimps  

Microsoft Academic Search

Sexual systems vary considerably among caridean shrimps and while most species are gonochoric, others are described as sequential\\u000a protandric hermaphrodites or simultaneous hermaphrodites with an early male phase. At present, there is confusion about the\\u000a sexual system exhibited by several species mostly because those studies attempting to reveal their sexual system draw inferences\\u000a solely from the distribution of the sexes

Nuxia L. Espinoza-Fuenzalida; Martin Thiel; Enrique Dupre; J. Antonio Baeza

2008-01-01

420

Amelioration of sexual fantasies to sexual abuse cues in an adult survivor of childhood sexual abuse: A case study  

Microsoft Academic Search

Although sexual dysfunction of childhood sexual abuse survivors has received considerable attention, other sexual difficulties experienced by survivors of CSA, such as sexual fantasies to cues of sexual abuse, have received less attention. In this A–B design case study, a young adult female survivor of childhood sexual abuse presented for treatment at a Midwest rape crisis center. After successful treatment

Jane E. Wilson; Keith M. Wilson

2008-01-01

421

Perceptions of Sexuality as Related to Sexual Functioning and Sexual Risk in Women with Different Types of Childhood Abuse Histories  

Microsoft Academic Search

Perceptions of one's sexuality, self-reported sexual functioning, and sexual risk were examined in a community sample of 148 women with histories of either childhood sexual abuse (n = 26), both childhood sexual and physical abuse (n = 44), and neither form of abuse (n = 78). Controlling for depression and anxiety, the groups did not differ on sexual desire, arousal\\/orgasm,

Kelly A. Schloredt; Julia R. Heiman

2003-01-01

422

The impact of sexual trauma on sexual desire and function.  

PubMed

The field of sexual trauma is one of the most controversial and value-laden in mental health. The three factors which most affect adult sexual desire and function are the type of sexual trauma, how the sexual incidents were dealt with at the time and, most important, whether the person views her/himself as a survivor or victim. The assessment and treatment program described focuses on couple sex therapy with a special focus on processing the sexual trauma, honoring the person's veto and being 'partners in healing'. The core therapeutic theme is valuing intimate, erotic sexuality, which reinforces being a proud survivor rather than a shameful, anxious or angry victim. It is crucial to create a relapse prevention program to ensure that the person with the sexual trauma history continues to experience the positive roles of adult couple sexuality. PMID:22005207

McCarthy, Barry; Farr, Emily

2011-01-01

423

The Impact of Sexual Orientation on Sexuality and Sexual Practices in North American Medical Students  

PubMed Central

Introduction There has been limited investigation of the sexuality and sexual dysfunction in non-heterosexual subjects by the sexual medicine community. Additional research in these populations is needed. Aims To investigate and compare sexuality and sexual function in students of varying sexual orientations. Methods An internet-based survey on sexuality was administered to medical students in North American between the months of February and July of 2008. Main Outcome Measures All subjects provided information on their ethnodemographic characteristics, sexual orientation, and sexual history. Subjects also completed a series of widely-utilized instruments for the assessment of human sexuality (International Index of Erectile Function [IIEF], Female Sexual Function Index [FSFI], Premature Ejaculation Diagnostic Tool [PEDT], Index of Sex Life [ISL]). Results There were 2,276 completed responses to the question on sexual orientation. 13.2% of male respondents and 4.7% of female respondents reported a homosexual orientation; 2.5% of male and 5.7% of female respondents reported a bisexual orientation. Many heterosexual males and females reported same-sex sexual experiences (4% and 10%, respectively). Opposite-sex experiences were very common in the male and female homosexual population (37% and 44%, respectively). The prevalence of premature ejaculation (PEDT > 8) was similar among heterosexual and homosexual men (16% and 17%, P = 0.7, respectively). Erectile dysfunction (IIEF-EF < 26) was more common in homosexual men relative to heterosexual men (24% vs. 12%, P = 0.02). High risk for female sexual dysfunction (FSFI < 26.55) was more common in heterosexual and bisexual women compared with lesbians (51%, 45%, and 29%, respectively, P = 0.005). Conclusion In this survey of highly educated young professionals, numerous similarities and some important differences in sexuality and sexual function were noted based on sexual orientation. It is unclear whether the dissimilarities represent differing relative prevalence of sexual problems or discrepancies in patterns of sex behavior and interpretation of the survey questions. PMID:20384941

Breyer, Benjamin N.; Smith, James F.; Eisenberg, Michael L.; Ando, Kathryn A.; Rowen, Tami S.; Shindel, Alan W.

2013-01-01

424

SHARED ITS DNA SUBSTITUTIONS IN ISOLATES OF OPPOSITE MATING TYPE REVEAL A RECOMBIING HISTORY FOR THREE PRESUMED ASEXUAL SPECIES IN THE FILAMENTOUS ASCOMYCETE GENUS ALTERNARIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

About 15,000 species of ascomycete fungi lack a known sexual state. For fungi with asexual states in the form genera Embellisia, Ulocladium and Alternaria, six species have known sexual states but more than 50 species do not. In sexual filamentous ascomycetes, opposite mating type information at t...

425

Adolescent sexuality and disability.  

PubMed

Regardless of what our beliefs about sex and disability may be, as health care providers we can promote the health and well being of our patients with disabilities in several ways. First and perhaps foremost, physical and programmatic barriers to accessing general health care including routine gynecologic care must be dramatically reduced. The promise of Title III of the Americans with Disabilities Act must be aggressively extended to our health care system to ensure equal access to routine health care for all. Second, knowledge of community resources that can support the healthy development and exercise of responsible and satisfying sexuality is critical. For example, health care providers should know about adaptive and assistive technologies as well as the use of personal care assistants to support the healthy although sometimes nontypical expression of one's sexuality. Centers for Independent Living are community resources that are often underutilized by the medical profession. These centers--run by and for people with disabilities--are likely resources and allies for providing education, role models, and peer mentoring around relationships, intimacy, sexuality, sexual expression, and parenting with a disability. Finally, sex education is a must and should include the following: Basic facts of life, reproduction, and sexual intercourse; Human growth and development Human reproduction and anatomy Self-pleasuring/masturbation and the use of sexual aids Intimacy and privacy Pregnancy and child birth Contraception and abortion Family life and parenthood Sexual response and consensual sex Sexual orientation Sexual abuse HIV/AIDS and other sexually transmitted diseases. The question should not be whether sex education is provided to persons with disabilities, but rather how it is most effectively provided. Health sex education must include the development of effective communication skills, decision-making skills, assertiveness, and the ability to say "no." It must also include ways to create satisfying relationships. For more information about sex education as it relates to people with disabilities, the following abbreviated resource list may be helpful: http://www.sexualhealth.com http://www.lookingglass.com Ludwig S, Hingsburger, D. Being sexual: an illustrated series on sexuality and relationships. SIECCAN, 850 Coxwell, Aven., East York, Ontario, M4C 5R1 Tel: 416-466-5304; Fax: 416-778-0785. Sexuality Information and Education Council of the United States (SIECUS), 130 West 42nd Street, Suite 350, New York, NY 10036. Tel: 212-819-9770. National Information Center for Children and Youth with Disabilities (NICHCY), P.O. Box 1492, Washington, DC 20013; Tel/TTY: 800-695-0285; Fax: 202-884-8641; Internet: www.nichcy.org Non-Latex Supplies (Ask your pharmacist if not available) Trojan-Supra: http://www.trojancondoms.com Durex-Avanti: http://www.durex.com Female Health Company-FC Female Condom http://www.femalehealth.com Pasante--EzOn http://www.postalcondoms.co.uk (available in Canada and U.K.). PMID:12465564

Neufeld, Jacob A; Klingbeil, Fred; Bryen, Diane Nelson; Silverman, Brett; Thomas, Anila

2002-11-01

426

Reversed sexual conflict in a promiscuous antelope.  

PubMed

A general tenet of sexual conflict theory is that males have higher optimum mating rates than do females and therefore should be more persistent when it comes to mating. However, in promiscuous species, females might benefit from high mating rates as a result of increased conception probability with favored males, whereas favored males benefit from mating selectively because of sperm depletion. When this results in higher optimum mating rates for females than for males, there is potential for reversed sexual conflicts between persistent females and resistant males. Here I report evidence of such a reversed sexual conflict in a promiscuous antelope, the African topi. Rather than mating randomly, favored males prefer to balance mating investment equally between females as predicted by strategic sperm allocation theory. Females, however, enhance their probability of mating with favored males through aggression toward mating pairs. Supporting the idea that aggressive females thereby harass males to mate at a rate that is suboptimal from the males' perspective, males become increasingly likely to counterattack aggressive females with whom they have already mated disproportionately, and such male counterattacks are associated with refusal to mate with the aggressive females. This study points to reversed sexual conflict as a more significant evolutionary force in promiscuous mammals than previously thought; however, such conflicts probably often go unnoticed because males, in contrast to females, can avoid mating without conspicuous resistance. PMID:18060785

Bro-Jørgensen, Jakob

2007-12-18

427

Gender, Religiosity, Sexual Activity, Sexual Knowledge, and Attitudes Toward Controversial Aspects of Sexuality.  

PubMed

The purpose of this study is to examine the role of gender, religiosity, sexual activity, and sexual knowledge in predicting attitudes toward controversial aspects of sexuality among Turkish university students. Participants were 162 female and 135 male undergraduate students who were recruited on a volunteer basis from an urban state university in Turkey. The SKAT-A Attitude Scale along with background information form, sexual activities inventory, and sexual knowledge scale were administered to the participants. Simultaneous multiple regression analyses revealed that religiosity, particularly attendance to religious services was the most significant predictor in explaining university students' attitudes toward masturbation, abortion, homosexuality, pornography, and sexual coercion. PMID:24510128

Sümer, Zeynep Hatipo?lu

2014-02-01

428

Interest in reproducing long-extinct Carolina parakeet surfaces  

NSDL National Science Digital Library

Species extinction continues to be a hotly debated topic among scientists and other such intelligent and curious persons. The Americas have certainly seen a number of well-documented extinctions over the past several centuries, many of which can be at least partially attributed to humans. Perhaps one of the most well known was that of the passenger pigeon, which was declared extinct in 1914. Another such species was the Carolina parakeet, the only parrot native to South Carolina. The last known individual bird known to humans was eaten by a pig in the 1890s, but there has been a resurgence of interest in using DNA obtained from various egg shells in the collection of various museums in an attempt to bring these birds back. While most scientists remain skeptical of such "Jurassic Park"-techniques, Andy Kratter, the curator at the Florida Museum of Natural History remarked that, "It's an interesting question.� Regardless, there are no detailed plans as yet to undertake such an endeavor, so residents of the American Southeast will have to remain content with such native bird species as the snowy egret and the great blue heron.The first link will lead visitors to a news story from USA Today that talks about the possibility of reproducing the Carolina parakeet from DNA samples. The second link will take visitors to a site that provides some nice details about the extinct Carolina parakeet, including its habitat preferences and its general appearance. The third link leads to a page that offers some first-hand observations of the passenger pigeon, including those offered by John James Audubon and John Muir. The fourth link leads to the homepage of BirdLife International , which is a "global alliance of conservation organizations working together for the world's birds and people.� The fifth link takes visitors to a site that offers the sounds and calls of some of Florida's birds, along with a selection of short video clips for some of the species. The final link, provided by the San Diego Natural History Museum, offers some insights into the science of the film "Jurassic Park," which examined the possibility that dinosaurs might be brought back to life, and what the consequences might be.

429

Divergence in androgen sensitivity contributes to population differences in sexual dimorphism of electrocommunication behavior  

PubMed Central

Weakly-electric fish (Apteronotidae) produce highly diverse electrocommunication signals. Electric organ discharges (EODs) vary across species, sexes, and in the magnitude and direction of their sexual dimorphism. Gonadal steroid hormones can modulate EODs, and differences in androgen sensitivity are hypothesized to underlie variation in the degree of sexual dimorphism across species. In this study, we asked whether variation in androgen sensitivity explained variation in sexual dimorphism of EODs within species, at the population level. We examined two populations of black ghost knifefish (Apteronotus albifrons), one from the Orinoco and the other from the Amazon river basin. EOD frequency (EODf) and chirp rates were measured to characterize diversity in sexual dimorphism across populations. The magnitude of sexual dimorphism in EODf differed significantly across populations, and was more pronounced in the Orinoco population than in the Amazon population. Chirp rates were sexually monomorphic in both populations. 11-ketotestosterone (11-kT) was administered over a two-week period to assess population differences in sensitivity to androgens. 11-kT masculinized EODf significantly more in the population with the greater degree of sexual dimorphism. 11-kT had no effect on the sexually monomorphic chirping rates. We conclude that population divergence in androgen sensitivity contributes to variation in sexual dimorphism of EODf in A. albifrons. PMID:23142327

Ho, Winnie W.; Rack, Jessie M.; Smith, G. Troy

2013-01-01

430

Divergence in androgen sensitivity contributes to population differences in sexual dimorphism of electrocommunication behavior.  

PubMed

Weakly-electric fish (Apteronotidae) produce highly diverse electrocommunication signals. Electric organ discharges (EODs) vary across species, sexes, and in the magnitude and direction of their sexual dimorphism. Gonadal steroid hormones can modulate EODs, and differences in androgen sensitivity are hypothesized to underlie variation in the degree of sexual dimorphism across species. In this study, we asked whether variation in androgen sensitivity explained variation in sexual dimorphism of EODs within species, at the population level. We examined two populations of black ghost knifefish (Apteronotus albifrons), one from the Orinoco and the other from the Amazon River Basin. EOD frequency (EODf) and chirp rates were measured to characterize diversity in sexual dimorphism across populations. The magnitude of sexual dimorphism in EODf differed significantly across populations, and was more pronounced in the Orinoco population than in the Amazon population. Chirp rates were sexually monomorphic in both populations. 11-Ketotestosterone (11-kT) was administered over a two-week period to assess population differences in sensitivity to androgens. 11-kT masculinized EODf significantly more in the population with the greater degree of sexual dimorphism. 11-kT had no effect on the sexually monomorphic chirping rates. We conclude that population divergence in androgen sensitivity contributes to variation in sexual dimorphism of EODf in A. albifrons. PMID:23142327

Ho, Winnie W; Rack, Jessie M; Smith, G Troy

2013-01-01

431

Anodyspareunia: a novel sexual dysfunction? An exploration into anal sexuality  

Microsoft Academic Search

Mounting evidence suggests anal intercourse amongst both heterosexual and homosexual persons is an increasingly prevalent form of sexual expression, yet associated problems presenting to psychosexual services are a relative rarity. What constitutes ‘normal’ sexual satiety within the realms of anal sexuality remains an enigma to many, both therapists and clients alike. The term anodyspareunia has been proposed to denote a

Karl Hollows

2007-01-01

432

Sexual compulsion – Relationship with sex, attachment and sexual orientation  

PubMed Central

Background and aims Sexual addiction, also known as hypersexual disorder, is associated with serious psychosocial problems for many people. Methods This study used questionnaires to investigate the effects of gender, sexual orientation and attachment (avoidance and anxiety) on sexual compulsion among 100 heterosexual and homosexual men and women. Results A positive correlation was found between anxious attachment and sexual compulsivity (r = 0.46; p < 0.01) and a positive correlation between avoidant attachment and sexual compulsivity (r = 0.39; p ? 0.01) in all participants. Secondly, an analysis of covariance showed a gender by sexual orientation interaction effect [F(1, 103) = 6.39, p < 0.01] but no attachment effect on sexual compulsivity. A follow-up comparison showed that lesbian women had higher rates of sexual compulsivity than heterosexual women [t (2, 50) = 5.08, p < 0.001] whereas there was non-significant difference in sexual compulsivity between homosexual and heterosexual men [t (2, 50) = 1.30, p = N.S.]. Discussion The results provide preliminary evidence for an association between attachment and sexual compulsivity and the effects of gender and sexual orientation on sexual compulsivity. PMID:25786496

KATZ, LICHEN; EBERHARDT, HILA; COHEN, KOBY; LEJOYEUX, MICHEL

2015-01-01

433

ORIGINAL PAPER Sexual Victimization, Alcohol Intoxication, Sexual-Emotional  

E-print Network

in the past year, completed childhood sexual abuse (CSA) and adolescent/adult sexual assault(ASA) measures indicating that, compared to non- victimized counterparts, sexually victimized women respond differently, Gender, and Reproduction, Indiana University, Bloomington, IN, USA J. Norris Alcohol and Drug Abuse

434

Cortisol, Sexual Arousal, and Affect in Response to Sexual Stimuli  

Microsoft Academic Search

Introduction. Theoretically, the physiological response to stress should inhibit the sexual response. This has been demonstrated experimentally in animal models, and correlationally in studies of human reproduction. It is reasonable to expect, then, that the stress response would be blunted during sexual arousal, and several researchers have found a pattern of decreasing cortisol during sexual arousal. Aim. In the present

Lisa Dawn Hamilton; Alessandra H. Rellini; Cindy M. Meston

2008-01-01

435

Sexual Abuse, Incest, and Sexual Exploitation: Mental Health Practitioners' Perspective.  

ERIC Educational Resources Information Center

Reports on a 33-item questionnaire based on Alexander G. Zaphiris's conceptualization of the terminology of sexual mistreatment. Results indicate that mental health counselors (N=300) who encountered sexual abuse, incest, and sexual exploitation agreed with Zaphiris's conceptualization but did not use this system of classification in actual…

Freet, Mary A.; Scalise, Joseph J.; Ginter, Earl J.

1996-01-01

436

Sexual victimization in the history of sexual abusers: A review  

Microsoft Academic Search

The present paper reviews the empirical literature on the proportion of child sexual abusers who were themselves sexually victimized as children. While findings in individual studies ranged between 0% and 67%, on average about 28% of the offenders reported being sexually victimized as children. This rate is higher than the base rate for community samples of non-offending males (about 10%),

R. K. Hanson; S. Slater

1988-01-01

437

Sexual Coercion Content in 21 Sexuality Education Curricula.  

ERIC Educational Resources Information Center

Examined adolescent sexuality-education curricula for information on coercion (date rape, stranger rape, pressure, incest, sexual harassment, unwanted/inappropriate touch, and exploitation/victimization). Exploitation/victimization and pressure received the greatest attention. Sexual harassment was not covered in any of the curricula. Results…

Beyer, Christine E.; Ogletree, Roberta J.

1998-01-01

438

Estimating sexual behavior parameters from routine sexual behavior data  

Microsoft Academic Search

In mathematical models for predicting the spread of sexually transmitted diseases (STDs), the rate of acquisition of new sex partners and concurrency, the number of simultaneous sexual partnerships, are important parameters. Yet, information on these parameters is rarely obtained in routine sexual behavior surveys; instead, questions about the total number of sex partners during specific periods are often asked. We

Carina Van Vliet; Catharina P. B. Van der Ploeg; Nancy Kidula; Isaac M. Malonza; Mark Tyndall; Nico J. D. Nagelkerke

1998-01-01

439

Association of Sexual Revictimization with Sexuality and Psychological Function  

ERIC Educational Resources Information Center

This study explores the associations of sexual revictimization (experiencing sexual abuse in childhood and adulthood) in a sample of 230 African American women who are low-income. Data indicate that women who experience sexual revictimization are more at risk for emotional stress and psychological pathology than women with no history of abuse. In…

Miner, Michael H.; Flitter, Jill M. Klotz; Robinson, Beatrice E.

2006-01-01

440

Sexual functioning following renal transplantation.  

PubMed

This study describes the prevalence of and investigates variables associated with problems in sexual functioning for a sample of 347 individuals following renal transplantation. Sexual problem was conceptualized through three continuous variables: lack of interest in sex; lack of enjoyment of sex; and difficulty becoming sexually aroused. Between 50 percent and 55 percent of respondents reported no sexual difficulties. The remaining respondents indicated from mild to severe problems. Multiple regression was used to examine predictors of problems with sexual functioning. Variables in the final model associated with sexual problems were older age and lower patient perceptions of physical and mental well-being. Assessment of and education regarding sexual functioning must be a routine component of psychosocial intervention. Future research warrants investigation of the meaning of sexual function for this population. PMID:14679705

Raiz, Lisa; Davies, Elizabeth A; Ferguson, Ronald M

2003-11-01

441

Sexual Selection III: Intersexual Competition  

E-print Network

Promiscuity or Polygyny Intense Sexual Selection Mostly Intrasexual Monogamy Weak Sexual Selection Mostly Elephant Seal 100 8 Red Deer 24 14 Humans 888 69 Black-legged Kittiwake 26 28 Kittiwake is monogamous

Blouin-Demers, Gabriel

442

Sexuality Attitudes of Black Adults.  

ERIC Educational Resources Information Center

Assessed sexuality attitudes of black middle-class sample (N=124) concerning communication regarding sexuality information, adolescent contraception, adolescent pregnancy, nonmarital intercourse, responsibility for contraception and pregnancy, abortion, pornography, and masturbation. Results suggest that participants were well-informed, moderate,…

Timberlake, Constance A.; Carpenter, Wayne D.

1990-01-01

443

Hepatitis C: Sex and Sexuality  

MedlinePLUS

... pass hepatitis C through other types of sexual contact, such as oral and anal sex? We do ... of spreading the hepatitis C virus through sexual contact? To reduce this chance, follow these guidelines: Have ...

444

SEXUALLY TRANSMITTED DISEASES SURVEILLANCE SYSTEM  

EPA Science Inventory

The Sexually Transmitted Disease Surveillance System presents statistics and trends for sexually transmitted diseases (STDs). Data demonstrate details which provide information about STD morbidity in the United States, STD prevalence with subgroups and populations which are the f...

445

Sexual Attraction and Orientation (Girls)  

MedlinePLUS

... might go beyond just thinking about it and experiment with sexual experiences with people of their own ... sexual orientation involves a complex mix of biology, psychology, and environmental factors . Scientists also believe a person's ...

446

Sexual Attraction and Orientation (Guys)  

MedlinePLUS

... might go beyond just thinking about it and experiment with sexual experiences with people of their own ... sexual orientation involves a complex mix of biology, psychology, and environmental factors . Scientists also believe a person's ...

447

Sexual Harassment in the Workplace.  

ERIC Educational Resources Information Center

Reviews the literature on sexual harassment to determine the issues the problem raises, its social contexts, and the resources available to working women. Examined the implications of sexual harassment for social work practice, policy, and research. (JAC)

Maypole, Donald E.; Skaine, Rosemarie

1983-01-01

448

Helping Teens Resist Sexual Pressure  

MedlinePLUS

... Pressure Ages & Stages Listen Helping Teens Resist Sexual Pressure Article Body Teens are more likely to have ... time they had intercourse. Helping Teens Resist Sexual Pressure “The pressure on teenagers to have sex is ...

449

Campus Climates for Sexual Minorities  

ERIC Educational Resources Information Center

Sexual minorities encounter unique challenges due to their sexual orientation, gender identity, or gender expression that often prevents them from achieving their full academic potential or participating fully in the campus community. (Contains 3 tables and 2 notes.)

Rankin, Susan R.

2005-01-01

450

Reproducible uniform equibiaxial stretch of precision-cut lung slices  

PubMed Central

Simulating ventilator-induced lung injury (VILI) in the laboratory requires stretching of lung alveolar tissue. Whereas precision-cut lung slices (PCLSs) are widely used for studying paracrine signaling pathways in the lungs, their use in stretch studies is very limited because of the technical challenge of fixing them to a stretchable substrate, stretching them uniformly, or holding them in a stretch device without causing rupture. We describe a novel method for attaching PCLSs to silicone membranes by stitching them together in a star-shaped pattern. Using a device that was previously designed in our laboratory for stretching primary alveolar epithelial cell monolayers, we demonstrate that in the central region of the PCLSs stretch is uniform, equibiaxial, and, after a short preconditioning period, also reproducible. The stitched and stretched PCLSs showed equal or better viability outcomes after 60 min of cyclic stretch at different magnitudes of physiological stretch compared with primary pulmonary alveolar epithelial cell monolayers. Preparing and stitching the PCLSs before stretch is relatively easy to perform, yields repeatable outcomes, and can be used with tissue from any species. Together with the ensuring uniform and equibiaxial stretch, the proposed methods provide an optimal model for VILI studies with PCLSs. PMID:23275624

Davidovich, N.; Huang, J.

2013-01-01

451

Species clarification of Ogasawara cockroaches which inhabit Japan.  

PubMed

The so-called "Ogasawara cockroaches" were examined by morphological observations and by breeding experiments to elucidate their actual taxonomical status. Fourteen groups (isolate) of "Ogasawara cockroaches" collected from Iwoto-A, Iwoto-B, Hahajima, Chichijima, Nishijima, Nakodojima, Tokunoshima-A, Tokunoshima-B, Okinawato- A, Okinawa-B, Amamiooshima, Miyakojima, Ishigakijima and Hawaii, were bred and passaged in our laboratory. Cockroaches collected from the field were first reared individually and the sexes of their offspring examined. Cockroaches collected from Iwoto, Tokushima and Okinawa, were found to consist of two groups; those whose offspring were all female and the other whose offspring consist of both male and female. Cross-breeding experiments showed that individuals from the group that did not produce any male but only female offspring were parthenogenetic. On the contrary, the group that have bisexual individuals produced both male and female offspring in a ratio of 1:1. Our results show that the so-called "Ogasawara cockroaches" consist of 2 species, namely, Pycnoscelus surinamensis and Pycnoscelus indicus. There are areas in which both species co-habitated together and there are also areas in which either only one of the two species can be found. The group that reproduces only female offspring and only through parthenogenesis was identified as P. surinamensis. The group that reproduces heterosexually and produce male and female offspring was identified as P. indicus. Thus, the so-called "Ogasawara cockroaches" found in Japan actually consist of 2 species, namely, P. surinamensis and P. indicus, which can be differentiated using the solitary breeding method to demonstrate parthenogenesis in the former and the need for sexual reproduction in the latter. PMID:25801258

Komatsu, N; Kawakami, Y; Banzai, A; Ooi, H K; Uchida, A

2015-03-01

452

Assessing the association between childhood sexual abuse and adult sexual experiences in women with sexual difficulties.  

PubMed

Self-report instruments for assessing sexual well-being in women with sexual difficulties have not to date been explicitly validated among women with a history of childhood sexual abuse (CSA). Given an extensive literature suggesting psychological differences between women with and without a history of CSA, it is possible that sexual well-being has a different meaning for these groups. Without validated scales, it is difficult to evaluate the impact of early sexual trauma on adult sexuality. The present study assessed whether the factor structure of widely used measures of sexual well-being were consistent across women experiencing sexual difficulties, with and without an abuse history, and to estimate effect sizes for the statistical effect of CSA on sexual well-being in this population. A sample of women with and without a history of CSA (N = 238) completed the Female Sexual Function Index and the Sexual Satisfaction Scale for Women. Structural equation models indicated generally consistent factor structures across groups, suggesting good construct validity. Effect size estimates indicated medium to large (0.53-0.72) effects of CSA on sexual well-being for women with sexual difficulties. These findings support and extend research regarding the potential effects of CSA that may inform treatment for this population. PMID:24948536

Stephenson, Kyle R; Pulverman, Carey S; Meston, Cindy M

2014-06-01

453

Associations between youth homelessness, sexual offenses, sexual victimization, and sexual risk behaviors: a systematic literature review.  

PubMed

Homeless youth commonly report engaging in sexual risk behaviors. These vulnerable young people also frequently report being sexually victimized. This systematic review collates, summarizes, and appraises published studies of youth investigating relationships between homelessness, perpetration of sexual offenses, experience of sexual victimization, and engagement in sexual risk behavior. A systematic search of seventeen psychology, health, and social science electronic databases was conducted. Search terms included "homeless*," "youth," "offend*," "victimization," "crime," "rape," "victim*," and "sex crimes." Thirty-eight studies were identified that met the inclusion criteria. Findings showed homeless youth commonly report being raped and sexually assaulted, fear being sexually victimized, and engage in street prostitution and survival sex. Rates of victimization and sexual risk behavior were generally higher for females. Given the paucity of longitudinal studies and limitations of current studies, it is unclear whether homelessness is prospectively associated with sexual victimization or engagement in sexual risk behavior, and whether such associations vary cross nationally and as a function of time and place. Future prospective research examining the influence of the situational context of homelessness is necessary to develop a better understanding of how homelessness influences the perpetration of sexual offenses, experience of sexual victimization, and engagement in sexual risk behavior among homeless youth. PMID:25411128

Heerde, Jessica A; Scholes-Balog, Kirsty E; Hemphill, Sheryl A

2015-01-01

454

Sexual Harassment: Identifying Risk Factors  

Microsoft Academic Search

A new model of the etiology of sexual harassment,the four-factor model, is presented and compared with several models of sexual harassment including the biological model, the organizational model, the sociocultural model,and the sexrole spillover model. A number of risk factors associated with sexually harassing behavior are examined within the framework of the four-factor model of sexual harassment. These include characteristics

Elizabeth A. O'Hare; William O'Donohue

1998-01-01

455

Sexual Abuse and Sexual Functioning in a Chronic Pelvic Pain Sample  

ERIC Educational Resources Information Center

Sexual abuse, particularly childhood sexual abuse, has been linked to chronic pelvic pain and to sexual dysfunction, though the sexual functioning of survivors of sexual abuse has not been studied in a chronic pain population. Sixty-three women with chronic pelvic pain completed measures of sexual function, sexual abuse, and pain. Using an index…

Randolph, Mary E.; Reddy, Diane M.

2006-01-01

456

ORIGINAL PAPER Predicting Sexual Problems in Women: The Relevance of Sexual  

E-print Network

ORIGINAL PAPER Predicting Sexual Problems in Women: The Relevance of Sexual Excitation and Sexual-clinical sample of 540 hetero- sexual women were used to examine the relationships between scores on the Sexual Excitation/Sexual Inhibition Inventory for Women (SESII-W) and ratings of current sexual problems, lifetime

457

Avoidance of Relatively Aggressive Male Japanese Quail (Coturnix japonica) by Sexually Experienced Conspecific Females  

E-print Network

Avoidance of Relatively Aggressive Male Japanese Quail (Coturnix japonica) by Sexually Experienced Sexually experienced female Japanese quail (Coturnix japonica) that are offered a choice between 2 the physical punishment that can result from contact with them. Japanese quail have become an important species

Galef Jr., Bennett G.

458

Neuroendocrine contributions to sexual partner preference in birds Elizabeth Adkins-Regan  

E-print Network

imprinting Social experience Sexual differentiation Homosexual behavior a b s t r a c t A majority of birds preferences for opposite-sex partners where the sexes form extended affiliative relationships. Zebra finches animal. In this species, sexual partner preference can be partially or largely sex reversed with hormone

459

Size dependency of sexual reproduction and of clonal growth in two perennial plants  

Microsoft Academic Search

We compared the size dependency of sexual reproduction and clonal growth in two clonal perennials that inhabit old fields, Aster lanceolatus and Solidago canadensis. In both species there was a threshold size required for sexual reproduction to occur, and above that threshold reproductive output increased linearly with vegetative mass. Biomass allocated to clonal growth was also highly correlated with vegetative

Bernhard Schmid; Fakhri A. Bazzaz; Jacob Weiner

1995-01-01

460

Asexuality cured: the relations and differences between sexual and asexual Apoanagyrus diversicornis  

Microsoft Academic Search

We investigated whether asexual (thelytokous) Apoanagyrus diversicornis and sexual (arrhenotokous) A. diversicornis (Hymenoptera: Encyrtidae) belong to the same biological species. The strains are allopatric and there are no morphological differences. The sexual A. diversicornis strain originates from south-western Brazil. It was introduced into Africa for the biological control of the cassava mealybug Phenacoccus manihoti. The asexual strain parasitizes P. herreni

Janine W A M Pijls; Hans J van Steenbergen; Jacques J M van Alphen; Janine WAM Pijls

1996-01-01

461

Genomic Insights into Sexual Selection and the Evolution of Reproductive Genes in Teleost Fishes  

E-print Network

..................................................................................................... 69 x 4. SEXUAL SELECTION AND THE EVOLUTION OF MALE PREGNANCY PROTEINS AMONG PIPEFISH AND SEAHORSE LINEAGES WITH DIVERSE MATING SYSTEMS ........................................................................ 75 Introduction..., many studies have suggested and in some cases demonstrated that variations in morphology of male intromittent organs across a diverse array of internally fertilizing animal species have arisen as a consequence of postcopulatory sexual selection...

Small, Clayton

2012-10-19

462

The evolution of exaggerated sexual swellings in primates and the graded-signal hypothesis  

Microsoft Academic Search

Females of some Old World primate taxa advertise their sexual receptivity with exaggerated sexual swellings. Although a number of hypotheses have been proposed, the function of this conspicuous trait remains unsolved. This review updates information on the phylogenetic distribution of exaggerated swellings and identifies aspects of the morphology, physiology and behaviour of species with this conspicuous trait. Some of these

Charles L. Nunn

1999-01-01

463

Dioecious Silene latifolia plants show sexual dimorphism in the vegetative stage  

Microsoft Academic Search

BACKGROUND: Prior to this study, no differences in gene expression between male and female dioecious plants in the vegetative state had been detected. Among dioecious plants displaying sexual dimorphism, Silene latifolia is one of the most studied species. Although many sexually dimorphic traits have been described in S. latifolia, all of them are quantitative, and they usually become apparent only

Jitka Zluvova; Jiri Zak; Bohuslav Janousek; Boris Vyskot

2010-01-01

464

[Migrant adolescents and sexuality].  

PubMed

Besides its emotional, hormonal and physical components, sexuality has also an important social function. Analyzing these interactions in immigrant adolescents who are challenged at the same time by developmental changes and modified cultural and social rules--especially if they differ from the rules assimilated during childhood--might help professionals to access better comprehension. Personal experience, individual and external resources, whether they are family oriented or professional, are prone to influence on behavior, perception and outcome related to sexual health. The subject is discussed on the base of scientific literature and medical practice. PMID:22787726

Renteria, Saira-Christine

2012-06-13

465

[Sexuality in Ancient Egypt].  

PubMed

The present article explores the sexuality in ancient Egypt. In particular in this article are presented the ways of concubinage (marriage, concubinage, adultery), the incest, loves of the pharaohs and of the common people, the freedom of choice in garments, the status of the hetairas and of the whores, the sexual perversions (male and female homosexuality, necrophilia, sodomism, bestiality, rape, masturbation, exhibitionism), the operations of the genitals (circumcision, excision, castration) and finally the level of knowledge in gynaecology, fertility, contraception and obstetrics that even today demands our admiration. PMID:7858632

Androutsos, G; Marketos, S

1994-10-01

466

Strategic concealment of sexual identity in an estrilid finch  

PubMed Central

One explanation for the evolution of sexual monomorphism is the sexual indistinguishability hypothesis, which argues that in group-living species individuals might benefit by concealing their sex to reduce sexual competition. We tested this hypothesis in long-tailed finches Poephila acuticauda. Males and females could not be reliably distinguished morphologically or by analysis of the reflectance spectra (300 to 700 nm) from the plumage and bill. Males seemed unable to distinguish the sex of an unfamiliar individual in the absence of behavioural cues; they were equally likely to court and copulate with unfamiliar males and females but rarely courted familiar males. Here we report the first experimental evidence that sexual monomorphism enables strategic concealment of sex. Males were more likely to reveal their sex when faced with a solitary unfamiliar individual than a group of unfamiliar individuals. When encountering an unfamiliar male that revealed his sex, subordinate males were more likely to conceal their sex than dominant males.

Langmore, N. E.; Bennett, A. T. D.

1999-01-01

467

Sexual Health in Prime Time  

ERIC Educational Resources Information Center

The term "sexual health" is often used in sexuality education without any concrete, operational definition, and students are left to ascertain the meaning for themselves. In the absence of a clear definition, students may adopt diverse or narrow understandings of this vague term, without learning the full scope of everything that sexual health…

Taverner, William J.

2006-01-01

468

Sexual harassment in the workplace  

Microsoft Academic Search

Emphasizes that sexual harassment covers a wide range of unacceptable activities, can be committed by a wide range of people, and can happen to almost anybody, irrespective of gender and age. Stresses the need to prevent sexual harassment, setting out the steps that can be taken under US law. Sees training as a key to stopping sexual harassment, briefly indicating

Steve Kim; Brian H. Kleiner

1999-01-01

469

Sexual Interaction in Nonclinical Couples.  

ERIC Educational Resources Information Center

Reports on the sexual functioning and interaction of 58 nonclinical heterosexual couples as measured by the Sexual Interaction System Scale (SISS). On all five SISS factors, the nonclinical sample scored significantly better than persons in therapy for sexual dysfunction; they also reported satisfactory relationship adjustment and high levels of…

Woody, Jane D.; D'Souza, Henry J.

1997-01-01

470

The "Right" Sexuality for Girls  

ERIC Educational Resources Information Center

Feminist researchers in psychology and education have been theorizing about the kind of sexuality girls ought to have. They are not afraid to investigate morality and what makes a good life. While they explore the meaning and cultural context of girls' sexual development, the good sexual life they describe may be an elusive ideal that, in the end,…

Lamb, Sharon

2008-01-01

471

Sexual Trauma, Spirituality, and Psychopathology  

ERIC Educational Resources Information Center

This study assessed the association between spirituality and psychopathology in a group of sexual abuse victims and controls with a focus on whether spirituality moderated the association between sexual trauma and psychopathology. Seventy-one sexual trauma victims were compared to 25 control subjects on spiritual well-being, the Eating Disorder…

Krejci, Mark J.; Thompson, Kevin M.; Simonich, Heather; Crosby, Ross D.; Donaldson, Mary Ann; Wonderlich, Stephen A.; Mitchell, James E.

2004-01-01

472

AIDS Knowledge and Sexual Responsibility.  

ERIC Educational Resources Information Center

Examines knowledge about Acquired Immune Deficiency Syndrome (AIDS) and sexual behavior among 221 midwestern high school and 153 college students. Findings for the 187 males and 187 females studied show that females were more knowledgeable about AIDS and more sexually responsible than males, and AIDS knowledge and level of sexual activity were…

Lamport, Lynda L.; Andre, Thomas

1993-01-01

473

Responding to Sexual Assault and  

E-print Network

Responding to Sexual Assault and Relationship Violence at UMBC Revised 06/27/11 #12;2 INTRODUCTION The UMBC community is committed to maintaining a campus environment that is both welcoming and safe. Sexual will not be tolerated at UMBC. PURPOSE The UMBC Sexual Assault Policy requires students, faculty and staff to report all

Maryland, Baltimore County, University of

474

Adolescent sexual health in Sweden  

Microsoft Academic Search

In Sweden, society’s attitudes towards teenage sexual relationships are liberal, and sexual and reproductive health issues are given high priority. Family and sex education has been taught in schools since the 1950s. The age of sexual consent is 15 years. Since 1975, abortion has been free on demand. Contraceptive counselling is free, easily available at family planning and youth health

K Edgardh

2002-01-01

475

About Sexually Transmitted Diseases (STDs)  

MedlinePLUS

KidsHealth > Teens > Sexual Health > STDs & Other Infections > About Sexually Transmitted Diseases (STDs) Print A A A Text Size What's in this article? ... doctor if you ever have questions about your sexual health. More Information For more information about the signs, ...

476

[Endocrinological diseases, metabolic diseases, sexuality].  

PubMed

Sexuality is regularly evaluated in media surveys. Relations between sexual problems and some chronic pathologies as diabetes or metabolic syndrome have been brought to light. Androgen deficiency in the aging male has become a topic of increasing interest. Hormones play an important role in sexual function and relation between hormonal status and metabolic data are now well established. PMID:25239542

Lemaire, Antoine

2014-10-01

477

The Psychology of Sexual Prejudice  

Microsoft Academic Search

Sexual prejudice refers to negative attitudes toward an individual because of her or his sexual orientation. In this article, the term is used to characterize heterosexuals' negative attitudes toward (a) homosexual behavior, (b) people with a homosexual or bisexual orientation, and (c) communities of gay, lesbian, and bisexual people. Sexual prejudice is a preferable term to homophobia because it conveys

Gregory M. Herek

2000-01-01

478

Psychophysiological aspects of sexual dysfunction  

Microsoft Academic Search

The argument is made that human sexual dysfunction is particularly well suited for investigation within the conceptual framework embraced by psychophysiology, due to the unique participation of both physiological and psychological components in the sexual response cycle. The literature relating psychophysiological research to the investigation of sexual dysfunction is reviewed, indicating promising applications in the diagnosis and treatment of some

John P. Hatch

1981-01-01

479

Sexual Education for Psychiatric Residents  

ERIC Educational Resources Information Center

Objective: The authors seek to promote sexuality curriculum development in departments of psychiatry. Methods: The authors first focus on educational philosophy about what residents can be taught about sexual topics and then provide numerical and narrative resident evaluation data following a 6-month, half day per week rotation in a sexuality

Levine, Stephen B.; Scott, David L.

2010-01-01

480

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