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1

The consequences of rare sexual reproduction by means of selfing in an otherwise clonally reproducing species  

PubMed Central

Clonal reproduction of diploids leads to an increase in heterozygosity over time. A single round of selfing will then create new homozygotic genotypes. Given the same allele frequencies, heritable genetic variation is larger when there are more extreme, i.e. homozygotic, genotypes. So after a long clonal expansion, one round of selfing increases heritable genetic variation, but any fully or partially recessive deleterious alleles simultaneously impose a fitness cost. Here we calculate that the cost of selfing in the yeast Saccharomyces is experienced only by a minority of zygotes. This allows a round of selfing to act as an evolutionary capacitor to unlock genetic variation previously found in a cryptic heterozygous form. We calculate the evolutionary consequences rather than the evolutionary causes of sex. We explore a range of parameter values describing sexual frequencies, focusing especially on the parameter values known for wild Saccharomyces. Our results are largely robust to many other parameter value choices, so long as meiosis is rare relative to the strength of selection on heterozygotes. Results may also be limited to organisms with a small number of genes. We therefore expect the same phenomenon in some other species with similar reproductive strategies.

Masel, Joanna; Lyttle, David N.

2011-01-01

2

Population Genetics of Two Asexually and Sexually Reproducing Psocids Species Inferred by the Analysis of Mitochondrial and Nuclear DNA Sequences  

PubMed Central

Background The psocids Liposcelis bostrychophila and L. entomophila (Psocoptera: Liposcelididae) are found throughout the world and are often associated with humans, food stores and habitations. These insects have developed high levels of resistance to various insecticides in grain storage systems. However, the population genetic structure and gene flow of psocids has not been well categorized, which is helpful to plan appropriate strategies for the control of these pests. Methodology/Principal Findings The two species were sampled from 15 localities in China and analyzed for polymorphisms at the mitochondrial DNA (Cytb) and ITS (ITS1-5.8S-ITS2) regions. In total, 177 individual L. bostrychophila and 272 individual L. entomophila were analysed. Both Cytb and ITS sequences showed high genetic diversity for the two species with haplotype diversities ranged from 0.154±0.126 to 1.000±0.045, and significant population differentiation (mean FST?=?0.358 for L. bostrychophila; mean FST?=?0.336 for L. entomophila) was also detected among populations investigated. A Mantel test indicated that for both species there was no evidence for isolation-by-distance (IBD). The neutrality test and mismatch distribution statistics revealed that the two species might have undergone population expansions in the past. Conclusion Both L. bostrychophila and L. entomophila displayed high genetic diversity and widespread population genetic differentiation within and between populations. The significant population differentiation detected for both psocids may be mainly due to other factors, such as genetic drift, inbreeding or control practices, and less by geographic distance since an IBD effect was not found.

Wei, Dan-Dan; Yuan, Ming-Long; Wang, Bao-Jun; Zhou, An-Wei; Dou, Wei; Wang, Jin-Jun

2012-01-01

3

Allee effect limits colonization success of sexually reproducing zooplankton.  

PubMed

Understanding the dynamics of populations at low density and the role of Allee effects is a priority due to concern about the decline of rare species and interest in colonization/invasion dynamics. Despite well-developed theory and observational support, experimental examinations of the Allee effect in natural systems are rare, partly because of logistical difficulties associated with experiments at low population density. We took advantage of fish introduction and removal in alpine lakes to experimentally test for the Allee effect at the whole-ecosystem scale. The large copepod Hesperodiaptomus shoshone is often extirpated from the water column by fish and sometimes fails to recover following fish disappearance, despite the presence of a long-lived egg bank. Population growth rate of this dioecious species may be limited by mate encounter rate, such that below some critical density a colonizing population will fail to establish. We conducted a multi-lake experiment in which H. shoshone was stocked at densities that bracketed our hypothesized critical density of 0.5-5 copoepods/m3. Successful recovery by the copepod was observed only in the lake with the highest initial density (3 copepods/m3). Copepods stocked into small cages at 3000 copepods/m3 survived and reproduced at rates comparable to natural populations, confirming that the lakes were suitable habitat for this species. In support of mate limitation as the mechanism underlying recovery failure, we found a significant positive relationship between mating success and density across experimental and natural H. shoshone populations. Furthermore, a mesocosm experiment provided evidence of increased per capita population growth rate with increasing population density in another diaptomid species, Skistodiaptomus pallidus. Together, these lines of evidence support the importance of the Allee effect to population recovery of H. shoshone in the Sierra Nevada, and to diaptomid copepods in general. PMID:18959313

Kramer, Andrew M; Sarnelle, Orlando; Knapp, Roland A

2008-10-01

4

The effects of intracranial implantation of estrogen on receptivity in sexually and asexually reproducing female whiptail lizards, Cnemidophorus inornatus and Cnemidophorus uniparens.  

PubMed

The ventromedial hypothalamus (VMH) is an important site in the neuroendocrine control of sexual receptivity in mammals. This study was conducted to determine if the VMH was also involved in estrogen induction of receptivity in whiptail lizards. Estradiol benzoate (EB) was implanted into the VMH of ovariectomized Cnemidophorus inornatus, a sexually reproducing species, and C. uniparens, a parthenogenetic species which displays "pseudosexual" behaviors similar to the sexual behaviors typical of both male and female C. inornatus. In both species, EB was significantly more effective in eliciting receptivity when implanted in the VMH than in other locations in the brain. These results support the idea that, as in mammals, the VMH is an important location of estrogen action in the control of receptive behaviors in both sexually and asexually reproducing whiptail lizards. PMID:1937427

Wade, J; Crews, D

1991-09-01

5

Mating Type Sequences in Asexually Reproducing Fusarium Species  

PubMed Central

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 members of the genus. The DNA sequences of the regions flanking the amplified MAT regions were obtained by inverse PCR. These data were used to develop diagnostic primers suitable for the clear amplification of conserved mating type sequences from any member of the genus Fusarium. By using these diagnostic primers, we identified mating types of 122 strains belonging to 22 species of Fusarium. The ? box and the HMG box from the mating type genes are transcribed in F. avenaceum, F. culmorum, F. poae, and F. semitectum. The novelty of the PCR-based mating type identification system that we developed is that this method can be used on a wide range of Fusarium species, which have proven or expected teleomorphs in different ascomycetous genera, including Calonectria, Gibberella, and Nectria.

Kerenyi, Zoltan; Moretti, Antonio; Waalwijk, Cees; Olah, Brigitta; Hornok, Laszlo

2004-01-01

6

Existence of two sexual races in the planarian species switching between asexual and sexual reproduction.  

PubMed

In certain planarian species that are able to switch between asexual and sexual reproduction, determining whether a sexual has the ability to switch to the asexual state is problematic, which renders the definition of sexuals controversial. We experimentally show the existence of two sexual races, acquired and innate, in the planarian Dugesia ryukyuensis. Acquired sexuals used in this study were experimentally switched from asexuals. Inbreeding of acquired sexuals produced both innate sexuals and asexuals, but inbreeding of innate sexuals produced innate sexuals only and no asexuals. Acquired sexuals, but not innate sexuals, were forced to become asexuals by ablation and regeneration (asexual induction). This suggests that acquired sexuals somehow retain asexual potential, while innate sexuals do not. We also found that acquired sexuals have the potential to develop hyperplastic and supernumerary ovaries, while innate sexuals do not. In this regard, acquired sexuals were more prolific than innate sexuals. The differences between acquired and innate sexuals will provide a structure for examining the mechanism underlying asexual and sexual reproduction in planarians. PMID:22468837

Kobayashi, Kazuya; Maezawa, Takanobu; Nakagawa, Haruka; Hoshi, Motonori

2012-04-01

7

Sexual reproduction in the invasive species Fallopia japonica (Polygonaceae)  

Microsoft Academic Search

Fallopia japonica (Polygonaceae) is an invasive perennial plant, well known in North America for its ability to spread aggressively via vegetative reproduction. The contribution of sexual reproduction to the distribution of this species is not well documented, and as a result, F. japonica is treated solely as a clonal species. To investigate the role of sexual reproduction in this species,

JENNIFER FORMAN; R. V. Kesseli

2003-01-01

8

Reproducing Gender? Discourses of Gender and Sexuality in Federally-Funded Sex Education  

Microsoft Academic Search

The construction of gender and sexuality in school-based sex education plays an instrumental role in the creation of U.S. teens' sexual subjectivities as well as in their reproductive health and educational equity outcomes. Currently, however, little is known about how federally-funded sex education curricula treat gender and sexuality, and the policy debate is limited to whether or not school-based sex

Leah Curran

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.

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

2012-01-01

10

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

PubMed

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

2011-10-12

11

Linkage disequilibrium and spatial aggregation of genotypes in sexually reproducing populations of Erysiphe necator.  

PubMed

Random mating and recombination in heterothallic ascomycetes should result in high genotypic diversity, 1:1 mating-type ratios, and random associations of alleles, or linkage equilibrium, at different loci. To test for random mating in populations of the grape powdery mildew fungus Erysiphe necator, we sampled isolates from vineyards of Vitis vinifera in Burdett, NY (NY09) and Winchester, VA (VA09) at the end of the epidemic in fall 2009. We also sampled isolates from the same Winchester, VA vineyard in spring 2010 at the onset of the next epidemic. Isolates were genotyped for mating type and 11 microsatellite markers. In the spring sample, which originated from ascospore infections, nearly every isolate had a unique genotype. In contrast, fall populations were less diverse. In all, 9 of 45 total genotypes in VA09 were represented by two or more isolates; 3 of 40 total genotypes in NY09 were represented by two or more isolates, with 1 genotype represented by 20 isolates. After clone correction, mating-type ratios in the three populations did not deviate from 1:1. However, even with clone correction, we detected significant linkage disequilibrium (LD) in all populations. Mantel tests detected positive correlations between genetic and physical distances within vineyards. Spatial autocorrelation showed aggregations up to 42 and 3 m in VA09 and NY09, respectively. Spatial autocorrelation most likely results from short dispersal distances. Overall, these results suggest that spatial genetic aggregation and clonal genotypes that arise during the asexual phase of the epidemic contribute to persistent LD even though populations undergo sexual reproduction annually. PMID:22755546

Brewer, Marin Talbot; Frenkel, Omer; Milgroom, Michael G

2012-10-01

12

Sexual selection and species recognition in the pygmy swordtail, Xiphophorus pygmaeus : conflicting preferences  

Microsoft Academic Search

Sexual selection and species recognition play important roles in mate choice; however, sexual selection preferences may overlap with traits found in heterospecifics, producing a conflict between sexual selection and species recognition. We examined female preferences in Xiphophorus pygmaeus for male traits that could provide both types of information to determine how females use multiple cues when preferences for these cues

Shala J. Hankison; Molly R. Morris

2002-01-01

13

Sexual selection and a secondary sexual character in two Drosophila species  

Microsoft Academic Search

Evidence of sexual selection on male body size and on the number and symmetry of sternopleural bristles and of sex comb teeth was sought in natural populations of twoDrosophilaspecies. Body size did not differ between mating and non-mating males in either species. Mating maleD. simulanshad significantly fewer sex comb teeth than did males not found copulating, and mating maleD. pseudoobscurahad

THERESE ANN MARKOW; DAVID BUSTOZ; SCOTT PITNICK

1996-01-01

14

Multisite Reproducibility of the Broth Microdilution Method for Susceptibility Testing of Nocardia Species  

PubMed Central

Antimicrobial susceptibility testing (AST) of clinical isolates of Nocardia is recommended to detect resistance to commonly used antimicrobial agents; such testing is complicated by difficulties in inoculum preparation and test interpretation. In this study, six laboratories performed repetitive broth microdilution testing on single strains of Nocardia brasiliensis, Nocardia cyriacigeorgica, Nocardia farcinica, Nocardia nova, and Nocardia wallacei. For each isolate, a total of 30 microdilution panels from three different lots were tested at most sites. The goal of the study was to determine the inter- and intralaboratory reproducibility of susceptibility testing of this group of isolates. Acceptable agreement (>90% agreement at ±1 dilution of the MIC mode) was found for amikacin, ciprofloxacin, clarithromycin, and moxifloxacin. After eliminating MIC values from single laboratories whose results showed the greatest deviation from those of the remaining laboratories, acceptable agreement was also found for amoxicillin-clavulanic acid, linezolid, minocycline, and tobramycin. Results showed unsatisfactory reproducibility of broth microdilution testing of ceftriaxone with N. cyriacigeorgica and N. wallacei, tigecycline with N. brasiliensis and N. cyriacigeorgica, and sulfonamides with N. farcinica and N. wallacei. N. nova ATCC BAA-2227 is proposed as a quality control organism for AST of Nocardia sp., and the use of a disk diffusion test for sulfisoxazole is proposed as a check of the adequacy of the inoculum and to confirm sulfonamide MIC results.

Brown-Elliott, Barbara A.; Wallace, Richard J.; Witebsky, Frank G.; Koziol, Deloris; Hall, Geraldine S.; Killian, Scott B.; Knapp, Cindy C.; Warshauer, David; Van, Tam; Wengenack, Nancy L.; Deml, Sharon; Woods, Gail L.

2012-01-01

15

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)

2010-01-01

16

Development of Reproducible EST-derived SSR Markers and Assessment of Genetic Diversity in Panax ginseng Cultivars and Related Species  

PubMed Central

Little is known about the genetics or genomics of Panax ginseng. In this study, we developed 70 expressed sequence tag-derived polymorphic simple sequence repeat markers by trials of 140 primer pairs. All of the 70 markers showed reproducible polymorphism among four Panax speciesand 19 of them were polymorphic in six P. ginseng cultivars. These markers segregated 1:2:1 manner of Mendelian inheritance in an F2 population of a cross between two P. ginseng cultivars, ‘Yunpoong’ and ‘Chunpoong’, indicating that these are reproducible and inheritable mappable markers. A phylogenetic analysis using the genotype data showed three distinctive groups: a P. ginseng-P. japonicus clade, P. notoginseng and P. quinquefolius, with similarity coefficients of 0.70. P. japonicus was intermingled with P. ginseng cultivars, indicating that both species have similar genetic backgrounds. P. ginseng cultivars were subdivided into three minor groups: an independent cultivar ‘Chunpoong’, a subgroup with three accessions including two cultivars, ‘Gumpoong’ and ‘Yunpoong’ and one landrace ‘Hwangsook’ and another subgroup with two accessions including one cultivar, ‘Gopoong’ and one landrace ‘Jakyung’. Each primer pair produced 1 to 4 bands, indicating that the ginseng genome has a highly replicated paleopolyploid genome structure.

Choi, Hong-Il; Kim, Nam Hoon; Kim, Jun Ha; Choi, Beom Soon; Ahn, In-Ok; Lee, Joon-Soo; Yang, Tae-Jin

2011-01-01

17

Sexual advertisement and immune function in an arachnid species (Lycosidae)  

Microsoft Academic Search

A simple version of the immunocompetence handicap hypothesizes that through condition-dependence, the size of the sexual trait may be positively related to immune function at the population level. In the present study, we investigated the relationship between sexual advertisement and immune function in a natural population of male wolf spiders, Hygrolycosa rubrofasciata (Araneae: Lycosidae). Males of H. rubrofasciata have a

Jari J. Ahtiainen; Rauno V. Alatalo; Raine Kortet; Markus J. Rantala

2004-01-01

18

Sexual conflict predicts morphology and behavior in two species of penduline tits  

PubMed Central

Background The evolutionary interests of males and females rarely coincide (sexual conflict), and these conflicting interests influence morphology, behavior and speciation in various organisms. We examined consequences of variation in sexual conflict in two closely-related passerine birds with contrasting breeding systems: the Eurasian penduline tit Remiz pendulinus (EPT) exhibiting a highly polygamous breeding system with sexually antagonistic interests over parental care, and the socially monogamous Cape penduline tit Anthoscopus minutus (CPT). We derived four a priori predictions from sexual conflict theory and tested these using data collected in Central Europe (EPT) and South Africa (CPT). Firstly, we predicted that EPTs exhibit more sexually dimorphic plumage than CPTs due to more intense sexual selection. Secondly, we expected brighter EPT males to provide less care than duller males. Thirdly, since song is a sexually selected trait in many birds, male EPTs were expected to exhibit more complex songs than CPT males. Finally, intense sexual conflict in EPT was expected to lead to low nest attendance as an indication of sexually antagonistic interests, whereas we expected more cooperation between parents in CPT consistent with their socially monogamous breeding system. Results Consistent with our predictions EPTs exhibited greater sexual dimorphism in plumage and more complex song than CPTs, and brighter EPT males provided less care than duller ones. EPT parents attended the nest less frequently and less simultaneously than CPT parents. Conclusions These results are consistent with sexual conflict theory: species in which sexual conflict is more manifested (EPT) exhibited a stronger sexual dimorphism and more elaborated sexually selected traits than species with less intense sexual conflict (CPT). Our results are also consistent with the notion that EPTs attempt to force their partner to work harder as expected under sexual conflict: each member of the breeding pair attempts to shift the costs of care to the other parent. More brightly colored males benefit more from desertion than dull ones, because they are more likely to remate with a new female. Taken together, the comparison between two closely related species with contrasting breeding systems suggest that sexual conflict over care has influenced the evolution of behavior and morphology in penduline tits.

2010-01-01

19

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

20

Perspective: female remating, operational sex ratio, and the arena of sexual selection in Drosophila species.  

PubMed

As commonly observed among closely related species within a variety of taxa, Drosophila species differ considerably in whether they exhibit sexual dimorphism in coloration or morphology. Those Drosophila species in which male external sexual characters are minimal or absent tend, instead, to have exaggerated ejaculate traits such as sperm gigantism or seminal nutrient donations. Underlying explanations for the interspecific differences in the presence of external morphological sexual dimorphism versus exaggerated ejaculate traits are addressed here by examining the opportunity for sexual selection on males to occur before versus after mating in 21 species of Drosophila. Female remating frequency, an important component of the operational sex ratio, differs widely among Drosophila species and appears to dictate whether the arena of sexual selection is prior to, as opposed to after, copulation. Infrequent female mating results in fewer mating opportunities for males and thus stronger competition for receptive females that favors the evolution of male characters that maximize mating success. On the other hand, rapid female remating results in overlapping ejaculates in the female reproductive tract, such that ejaculate traits which enhance fertilization success are favored. The strong association between female remating frequency in a given species and the presence of sexually selected external versus internal male characters indicates that the relationship be examined in other taxa as well. PMID:12389717

Markow, Therese Ann

2002-09-01

21

Developmental plasticity in sexual roles of butterfly species drives mutual sexual ornamentation.  

PubMed

Current explanations for why sexual ornaments are found in both sexes include genetic correlation, same sex competition, and mutual mate choice. In this study, we report developmental plasticity in mating behavior as induced by temperature during development in the butterfly Bicyclus anynana. Males and females reciprocally change their sexual roles depending on their larval rearing temperatures. This switch is correlated with a change in mating benefits to females and costs to males. The discrete seasonal environments, wet season and dry season, are known to produce the two developmental forms and as a consequence impose alternating, symmetrical patterns of sexual selection, one season on male ornaments, the following season on female ornaments. Thus, reciprocal selection through time may result in mutual sexual ornamentation. PMID:21212355

Prudic, Kathleen L; Jeon, Cheonha; Cao, Hui; Monteiro, Antónia

2011-01-01

22

Population structure of two beetle-associated yeasts: comparison of a New World asexual and an endemic Nearctic sexual species in the Metschnikowia clade.  

PubMed

The genetic structure of two related yeast species, one sexual and one asexual, was compared using polymorphic DNA markers. Although both yeasts propagate by asexual budding of haploid cells, Metschnikowia borealis reproduces sexually when compatible strains come in contact. To what extent this has occurred in nature was not known. As Candida ipomoeae is a closely related, asexual species, the two yeasts provide an excellent model system to assess the role of sexual reproduction in a biogeographic context. Natural isolates of the two species were characterized using several polymorphic DNA markers. As predicted for an organism whose reproduction is strictly clonal, C. ipomoeae exhibited low haplotype diversity, high linkage disequilibrium, and high population differentiation. In contrast, M. borealis had unique haplotypes in most isolates, lower population differentiation, and little linkage disequilibrium, demonstrating that sexual recombination is prevalent. Geographic gradients were identified in both species, indicating that historical and climatic factors both play a role in shaping the populations. The spatial structure is also thought to be influenced by the ecology of the small floricolous beetles (family Nitidulidae) that vector the yeasts. For example, Hawaiian strains of C. ipomoeae show evidence of having undergone a genetic bottleneck, most likely when the vector was introduced to the islands. The two haplotypes found in Hawaii were nearly identical and were also found in North and Central America. M. borealis had a more continuous distribution where the genetic markers follow latitudinal and longitudinal gradients. PMID:19319659

Wardlaw, Alison M; Berkers, Tanya E; Man, Karen C; Lachance, Marc-André

2009-03-25

23

Scent variation and hybridization cause the displacement of a sexually deceptive orchid species  

Microsoft Academic Search

In the sexually deceptive orchid genus Ophrys , reproductive isolation is based on the specifi c attraction of males of a single pollinator species, mostly bees, by mimicking the female sex pheromone of this species. Changes in the fl oral odor can lead to hybridization, introgression, and possibly speciation. We investigated hybrid swarms of O. lupercalis and O. iricolor on

J. Stokl; P. M. Schluter; T. F. Stuessy; H. F. Paulus; G. Assum; M. Ayasse

2008-01-01

24

The expansion history of a sexual and asexual species of Cortaderia in California, USA  

Microsoft Academic Search

Summary 1 The expansion histories of two South American species of Cortaderia , similar in morphology but differing profoundly in their breeding systems, were compared in California, USA. 2 Both species were introduced to California in the mid-1800s, but herbarium records indicate that the sexual C. selloana has expanded spatially at twice the rate of the asexual C. jubata .

John G. Lambrinos

2001-01-01

25

Species detection and identification in sexual organisms using population genetic theory and DNA sequences.  

PubMed

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

2013-01-04

26

Sexual and asexual reproduction in two species of Tethya (Porifera: Demospongiae) from a Mediterranean coastal lagoon  

Microsoft Academic Search

The sexual and asexual phases of reproductive cycles of two sponges, Tethya citrina and T. aurantium, living sympatrically in a Mediterranean coastal lagoon (Stagnone di Marsala, NW Sicily) were studied from samples collected over an 18-mo period. Both species are oviparous and gonochoric. They have a summer, partially overlapping, period of oocyte production, although T. citrina appear to mature earlier.

G. Corriero; M. Sarfi; P. Vaccaro

1996-01-01

27

Visual discrimination between two sexually deceptive Ophrys species by a bee pollinator  

Microsoft Academic Search

Almost all species of the orchid genus Ophrys are pollinated by sexual deception. The orchids mimic the sex pheromone of receptive female insects, mainly hymenopterans,\\u000a in order to attract males seeking to copulate. Most Ophrys species have achromatic flowers, but some exhibit a coloured perianth and a bright, conspicuous labellum pattern. We recently\\u000a showed that the pink perianth of Ophrys

M. Streinzer; T. Ellis; H. F. Paulus; J. Spaethe

2010-01-01

28

Chance establishment for sexual, semelparous species: overcoming the Allee effect.  

PubMed

We formalize the establishment process for a sexual, semelparous organism through the use of hierarchical probability modeling from parameters of survival, probability of being female, probability of being fertilized, and expected fecundity. We show how to calculate the expected per capita growth rate and probability of extinction. An Allee effect is observed if the expected population growth rate decreases as the initial population size decreases. The model can be further extended as a stochastic process to evaluate the probability of extinction in subsequent generations. One of the novel results is the formulation of an analytical probability distribution for the next generation population size. As case studies, we use the Chinese mitten crab (Eriocheir sinensis) and the apple snail (Pomacea canaliculata), both of which appear on the World Conservation Union's list of 100 worst invaders. We evaluate the strength of the Allee effect and conclude that apple snails experience a weak Allee effect and Chinese mitten crabs experience a strong Allee effect. We emphasize one scenario where the stochastic process reveals that invasion risk can be estimated by the probability of the survival of one fertilized female, because the expected fecundity for one surviving female overwhelms the system such that population persistence is almost certain. PMID:19368522

Jerde, Christopher L; Bampfylde, Caroline J; Lewis, Mark A

2009-06-01

29

Conflicting preferences within females: sexual selection versus species recognition  

PubMed Central

Preferences for mates within and between species are often harmonious, as traits that females prefer are usually more developed in conspecifics than heterospecifics. This need not be the case, however. When it is not, conflict between these arenas of mate choice can be resolved if females attend to different cues for each task. But this raises the potential for correlations among preferences to limit the opportunity for these two processes to operate independently. Here, we show that, within individual female pygmy swordtails (Xiphophorus pygmaeus), directional preferences for conspicuous ornamentation are inversely associated with discrimination against a sympatric heterospecific, Xiphophorus cortezi. Thus, mate choice among and within species need not be separate, independent processes; instead, they can be mechanistically intertwined. As a consequence, different arenas of mate choice can constrain one another, even when females assess multiple cues.

Rosenthal, Gil G.; Ryan, Michael J.

2011-01-01

30

Cryptic species within the Chydorus sphaericus species complex (Crustacea: Cladocera) revealed by molecular markers and sexual stage morphology.  

PubMed

The cosmopolitanism paradigm in the biogeography of freshwater invertebrates is currently being replaced by non-cosmopolitanism or continental endemism. Benthic water fleas (Cladocera) from the family Chydoridae were the first group of freshwater invertebrates for which non-cosmopolitanism and cryptic diversity was substantiated by morphological studies. Yet, little is known about genetic differentiation and evolutionary history of chydorid species complexes. Here we present the first analysis of the genetic versus morphological differentiation in a benthic cladoceran species complex-Chydorus sphaericus s. str. using sequence variation in a nuclear (ribosomal internal transcribed spacer 2, ITS-2) and a mitochondrial (cytochrome c oxidase subunit I, COI) genes in 50 Holarctic localities. We tested for continental endemism and cryptic diversity predicted by previous morphological studies. We found evidence for the presence of at least seven putative regional species in the Holarctic, at least three of them being distributed beyond a single continent. While the molecular and sexual stage characters showed general concordance on species lineages, parthenogenetic female characters lacked resolution or were unassociated with molecular lineages. We conclude that cryptic regional lineages of benthic cladocerans are apparent and that the sexual stages represent the most informative morphological source of species characters for this environmental indicator group. PMID:19049884

Belyaeva, Maria; Taylor, Derek J

2008-11-19

31

Enzymatic profiles of Enterobacter sakazakii and related species with special reference to the alpha-glucosidase reaction and reproducibility of the test system.  

PubMed

The enzymatic profiles of Enterobacter sakazakii, Enterobacter cloacae, Enterobacter aerogenes, and Enterobacter agglomerans were determined with the API ZYM system (API System S.A., La Balme Les Grottes, France). Each assay was performed three times. A simple formula was derived and applied to assess the reproducibility of the API ZYM tests. In addition, a separate alpha-glucosidase test was performed. All E. sakazakii isolates produced alpha-glucosidase, in contrast to the other Enterobacter isolates. No phosphoamidase activity was detected in any of the E. sakazakii isolates, whereas it was present in 72% of E. cloacae, 89% of E. agglomerans, and 100% of E. aerogenes isolates. It was concluded that detection of alpha-glucosidase permits rapid and reliable differentiation between E. sakazakii and other Enterobacter species. The reproducibilities of alpha-glucosidase and phosphoamidase reactions were estimated to be 89 and 81%, respectively. PMID:6386874

Muytjens, H L; van der Ros-van de Repe, J; van Druten, H A

1984-10-01

32

Molecular genetic analysis and ecological evidence reveals multiple cryptic species among thynnine wasp pollinators of sexually deceptive orchids  

Microsoft Academic Search

Sexually deceptive Chiloglottis orchids lure their male thynnine wasp pollinators to the flower by emitting semiochemicals that mimic the specific sex pheromone of the wasp. Sexual deception is possible because chemical rather than visual cues play the key role in wasp mate search, suggesting that cryptic wasp species may be frequent. We investigated this prospect among Neozeleboria wasp pollinators of

Kate E. Griffiths; John W. H. Trueman; Graham R. Brown; Rod Peakall

2011-01-01

33

KIND Reproducibles.  

ERIC Educational Resources Information Center

|Presented are 14 student worksheets for use in teaching about environmental conservation. Topics of these games, puzzles include pollution, rainforests, endangered species, habitat destruction, and solid waste. An answer sheet for teachers is included. (CW)|

KIND Teacher, 1990

1990-01-01

34

Species and sexual isolating mechanisms in sibling species of giant petrels Macronectes  

Microsoft Academic Search

The two sibling species of giant petrels Macronectes halli and M. giganteus are the dominant avian scavengers in the Southern Ocean ecosystem. They breed sympatrically at a number of sub-Antarctic sites. This paper synthesises data from a detailed study at South Georgia to examine the importance of various interspecific and intersexual differences between these closely related species. Morphological, breeding, dietary,

Stephen Hunter

1987-01-01

35

Stem cells from innate sexual but not acquired sexual planarians have the capability to form a sexual individual.  

PubMed

Planarian species may harbor as many as three populations with different reproductive strategies. Animals from innate asexual (AS) and innate sexual (InS) populations reproduce only by fission and cross-fertilization, respectively, whereas the third population switches seasonally between the two reproductive modes. AS worms can be experimentally sexualized by feeding them with minced InS worms; we termed the resulting animals "acquired sexual" (AqS) worms. Both AqS and InS worms exhibit sexualizing activity when used as feed, suggesting that they maintain their sexual state via endogenous sexualizing substances, although the mechanisms underlying determination of reproductive strategy and sexual switching in these metazoans remain enigmatic. Therefore, we compared the endogenous sexualizing activity of InS worms and AqS worms. First, we amputated mature worms and assessed if they could re-enter a sexual state. Regenerants of InS worms, but not AqS worms, were only sexual, indicating that sexual state regulation comprises two steps: (1) autonomous initiation of sexualizing substance production and (2) maintenance of the sexual state by continuous production of sexualizing substances. Next, InS neoblasts were characterized by transplantation, finding that they successfully engrafted, proliferated, and replaced all recipient cells. Under such conditions, the AS recipients of InS worm neoblasts, but not those of AqS worms, became sexual. These results clearly show that there is a neoblast-autonomous determination of reproductive strategy in planarians. PMID:22968921

Nodono, Hanae; Ishino, Yugo; Hoshi, Motonori; Matsumoto, Midori

2012-09-25

36

Female mating preference functions predict sexual selection against hybrids between sibling species of cichlid fish.  

PubMed

The evolutionary outcome of interspecific hybridization, i.e. collapse of species into a hybrid swarm, persistence or even divergence with reinforcement, depends on the balance between gene flow and selection against hybrids. If female mating preferences are open-ended but sign-inversed between species, they can theoretically be a source of such selection. Cichlid fish in African lakes have sustained high rates of speciation despite evidence for widespread hybridization, and sexual selection by female choice has been proposed as important in the origin and maintenance of species boundaries. However, it had never been tested whether hybridizing species have open-ended preference rules. Here we report the first experimental test using Pundamilia pundamilia, Pundamilia nyererei and their hybrids in three-way choice experiments. Hybrid males are phenotypically intermediate. Wild-caught females of both species have strong preferences for conspecific over heterospecific males. Their responses to F1 hybrid males are intermediate, but more similar to responses to conspecifics in one species and more similar to responses to heterospecifics in the other. We suggest that their mate choice mechanism may predispose haplochromine cichlids to maintain and perhaps undergo phenotypic diversification despite hybridization, and that species differences in female preference functions may predict the potential for adaptive trait transfer between hybridizing species. PMID:18508752

van der Sluijs, Inke; Van Dooren, Tom J M; Hofker, Kees D; van Alphen, Jacques J M; Stelkens, Rike B; Seehausen, Ole

2008-09-12

37

Scent variation and hybridization cause the displacement of a sexually deceptive orchid species.  

PubMed

In the sexually deceptive orchid genus Ophrys, reproductive isolation is based on the specific attraction of males of a single pollinator species, mostly bees, by mimicking the female sex pheromone of this species. Changes in the floral odor can lead to hybridization, introgression, and possibly speciation. We investigated hybrid swarms of O. lupercalis and O. iricolor on Sardinia using behavioral, electrophysiological (GC-EAD), chemical, morphological, and genetic methods (AFLPs). In behavioral experiments, approximately 20% of the flowers from both species and hybrids were attractive to the "wrong" or both pollinator species. Analysis of the EAD-active hydrocarbons in the floral odor showed an overlap in the two species, whereby hybrid individuals could not be separated from O. iricolor. The genetic analysis confirmed the hybridization of the species. Plants of O. iricolor and hybrids are genetically indistinguishable and form an O. iricolor × lupercalis hybrid population. Remaining plants of O. lupercalis will possibly be displaced by the O. iricolor × lupercalis hybrid population in the future. Our study showed that in deceptive orchids, variation in the pollinator attracting cues, in this case, scent, can be the first step for speciation and at the same time cause the displacement of a species. PMID:21632372

Stökl, Johannes; Schlüter, Philipp M; Stuessy, Tod F; Paulus, Hannes F; Assum, Günter; Ayasse, Manfred

2008-04-01

38

Altering sexual reproductive mode by interspecific exchange of MAT loci  

Technology Transfer Automated Retrieval System (TEKTRAN)

Sexual fungi can be self-sterile (heterothallic, requiring genetically distinct partners) or selffertile (homothallic, no partner required). In most ascomycetes, a single mating type locus (MAT) controls the ability to reproduce sexually. In the genus Cochliobolus, all heterothallic species have eit...

39

Genetic Structure of Two Protist Species (Myxogastria, Amoebozoa) Suggests Asexual Reproduction in Sexual Amoebae  

PubMed Central

Plasmodial slime molds (Myxogastria or Myxomycetes) are common and widespread unicellular organisms that are commonly assumed to have a sexual life cycle culminating with the formation of often macroscopic fruiting bodies that efficiently disseminate spores. However, laboratory studies based on mating compatibility revealed the coexistence of asexual as well as sexual strains. To test this hypothesis in natural populations, we investigated the genetic variability of two species of the genus Lamproderma. Detailed ecological relevés were carried out in 2007 and 2009 in several deep ravines in the Elbsandsteingebirge (Saxony, south-eastern Germany). Morphological characters of 93 specimens of Lamproderma were recorded and genetic analyses, based on the small subunit ribosomal gene, the internal transcribed spacer 1 and partial elongation factor 1? sequences were carried out for 52 specimens. Genetic analyses showed the existence of two major clades, each composed of several discrete lineages. Most of these lineages were composed of several identical sequences (SSU, ITS 1 and EF-1?) which is explained best by an asexual mode of reproduction. Detrended Correspondence Analysis of morphological characters revealed two morphospecies that corresponded to the two major clades, except for one genotype (Lc6), thus challenging the morphospecies concept. Genetic patterns were not related to the geographical distribution: specimens belonging to the same genotype were found in distinct ravines, suggesting effective long-distance dispersal via spores, except for the Lc6 genotype which was found only in one ravine. Implications for the morphological and biological species concept are discussed.

Fiore-Donno, Anna Maria; Novozhilov, Yuri K.; Meyer, Marianne; Schnittler, Martin

2011-01-01

40

Haldane's Rule: Hybrid Sterility Affects the Heterogametic Sex First because Sexual Differentiation is on the Path to Species Differentiation  

Microsoft Academic Search

Prevention of recombination is needed to preserve both phenotypic differentiation between species and sexual phenotypic differentiation within species. For species differentiation (speciation), isolating barriers preventing recombination may be pre-zygotic (gamete transfer barriers), or post-zygotic (either a developmental barrier resulting in hybrid inviability, or a chromosomal-pairing barrier resulting in hybrid sterility). The sterility barrier is usually the first to appear and,

D. R. FORSDYKE

2000-01-01

41

Circadian rhythms of sexual behavior and pheromone titers of two closely related moth species autographa gamma and Cornutiplusia circumflexa.  

PubMed

Two closely related plusiinae moths, Autographa gamma Linnaeus and Cornutiplusia circumflexa Linnaeus, are sympatric in Israel. Both species use identical sex pheromone components but in different ratios, and do not attempt to mate with each other. In addition to the effective reproductive separation by their sex pheromones, the sexual behavior of both species was compared to determine whether the lack of selection pressure might create additional barriers to cross-attraction and cross-mating. We found the gamma moth to be sexually active almost equally throughout the scotophase, whereas the sexual activity of C. circumflexa was limited to a short period at the end of the scotophase when most of the gamma moths had already mated. Higher levels of calling were observed with older females. There was a close relationship between pheromone titer and calling activity in both species. PMID:16132217

Mazor, Michal; Dunkelblum, Ezra

2005-08-17

42

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.

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

2004-01-01

43

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.

Webb, Thomas J.; Freckleton, Robert P.

2007-01-01

44

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

45

Effect of Adult Nutrition on Male Sexual Performance in Four Neotropical Fruit Fly Species of the Genus Anastrepha (Diptera: Tephritidae)  

Microsoft Academic Search

Fruit flies (Diptera: Tephritidae) have been used previously as a model to explore the effect of nutrition on male reproduction. Here we tested the hypothesis that adult feeding history influences male sexual performance in four species of neotropical fruit flies of the genus Anastrepha (A. ludens, A. obliqua, A. serpentina, and A. striata), an approach that allowed us to consider

Martín Aluja; Isabel Jácome; Rogelio Macías-Ordóñez

2001-01-01

46

Selection on body size and sexual size dimorphism differs between host species in a seed-feeding beetle  

Microsoft Academic Search

Sexual size dimorphism varies substantially among populations and species but we have little understanding of the sources of selection generating this variation. We used path analysis to study how oviposition host affects selection on body size in a seed-feeding beetle (Stator limbatus) in which males contribute large ejaculates (nuptial gifts) to females. Females use nutrients in these ejaculates for egg

C. W. FOX; M. E. CZESAK

2006-01-01

47

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

48

Analysis of conserved microRNAs in floral tissues of sexual and apomictic Boechera species  

PubMed Central

Background Apomixis or asexual seed formation represents a potentially important agronomic trait whose introduction into crop plants could be an effective way to fix and perpetuate a desirable genotype through successive seed generations. However, the gene regulatory pathways underlying apomixis remain unknown. In particular, the potential function of microRNAs, which are known to play crucial roles in many aspects of plant growth and development, remains to be determined with regards to the switch from sexual to apomictic reproduction. Results Using bioinformatics and microarray validation procedures, 51 miRNA families conserved among angiosperms were identified in Boechera. Microarray assay confirmed 15 of the miRNA families that were identified by bioinformatics techniques. 30 cDNA sequences representing 26 miRNAs could fold back into stable pre-miRNAs. 19 of these pre-miRNAs had miRNAs with Boechera-specific nucleotide substitutions (NSs). Analysis of the Gibbs free energy (?G) of these pre-miRNA stem-loops with NSs showed that the Boechera-specific miRNA NSs significantly (p ? 0.05) enhance the stability of stem-loops. Furthermore, six transcription factors, the Squamosa promoter binding protein like SPL6, SPL11 and SPL15, Myb domain protein 120 (MYB120), RELATED TO AP2.7 DNA binding (RAP2.7, TOE1 RAP2.7) and TCP family transcription factor 10 (TCP10) were found to be expressed in sexual or apomictic ovules. However, only SPL11 showed differential expression with significant (p ? 0.05) up-regulation at the megaspore mother cell (MMC) stage of ovule development in apomictic genotypes. Conclusions This study constitutes the first extensive insight into the conservation and expression of microRNAs in Boechera sexual and apomictic species. The miR156/157 target squamosa promoter binding protein-like 11 (SPL11) was found differentially expressed with significant (p ? 0.05) up-regulation at the MMC stage of ovule development in apomictic genotypes. The results also demonstrate that nucleotide changes in mature miRNAs significantly (p ? 0.05) enhance the thermodynamic stability of pre-miRNA stem-loops.

2011-01-01

49

Production of asexual and sexual offspring in the triploid sexual planarian Dugesia ryukyuensis.  

PubMed

Certain freshwater planarians reproduce asexually as well as sexually, and their chromosomal ploidies include polyploidy, aneuploidy and mixoploidy. Previously, we successfully performed an experiment in which a clonal population produced by asexual reproduction of the Dugesia ryukyuensis (OH strain) switched to the sexual mode of reproduction. Worms of this strain are triploid with a pericentric inversion on Chromosome 4. The worms were switched to sexual reproduction after being fed with sexually mature Bdellocephala brunnea, which is a sexually reproducing species. The resulting sexualized OH strain produced cocoons filled with several eggs. Two putative factors, Mendelian factor(s) and chromosomal control(s), have been proposed as determining the reproductive mode. The present study demonstrated that inbreeding of the resultant sexualized worms produced the following four types of offspring through sexual reproduction: diploid asexual worms, triploid asexual worms, diploid sexual worms and triploid sexual worms. The chromosomal mutation on Chromosome 4 was inherited by these offspring independent of their reproductive mode. These results provide two important pieces of information: (i) the putative genetic factor was not necessarily inherited in a Mendelian fashion; and (ii) the reproductive mode is not regulated by chromosomal changes such as polyploidy or chromosomal mutations. This suggests that asexuality in D. ryukyuensis is regulated by an unknown factor(s) other than a Mendelian factor or a chromosomal control. PMID:21392298

Kobayashi, Kazuya; Arioka, Sachiko; Hoshi, Motonori; Matsumoto, Midori

2009-09-01

50

Haldane's rule: hybrid sterility affects the heterogametic sex first because sexual differentiation is on the path to species differentiation.  

PubMed

Prevention of recombination is needed to preserve both phenotypic differentiation between species and sexual phenotypic differentiation within species. For species differentiation (speciation), isolating barriers preventing recombination may be pre-zygotic (gamete transfer barriers), or post-zygotic (either a developmental barrier resulting in hybrid inviability, or a chromosomal-pairing barrier resulting in hybrid sterility). The sterility barrier is usually the first to appear and, although often initially only manifest in the heterogametic sex (Haldane's rule), is finally manifest in both sexes. For sexual differentiation, the first and only barrier is chromosomal-pairing, and always applies to the heterogametic sex. For regions of sex chromosomes affecting sexual differentiation there must be something analogous to the process generating the hybrid sterility seen when allied species cross. Explanations for Haldane's rule have generally assumed that the chromosomal-pairing barrier initiating evolutionary divergence into species is due to incompatibilities between gene products ("genic), or sets of gene products ("polygenic), rather than between chromosomes per se ("chromosomal"). However, if chromosomal incompatibilities promoting incipient sexual differentiation could also contribute to the process of incipient speciation, then a step towards speciation would have been taken in the heterogametic sex. Thus, incipient speciation, manifest as hybrid sterility when "varieties" are crossed, would appear at the earliest stage in the heterogametic sex, even in genera with homomorphic sex chromosomes (Haldane's rule for hybrid sterility). In contrast, it has been proposed that Haldane's rule for hybrid inviability needs differences in dosage compensation, so could not apply to genera with homomorphic sex chromosomes. PMID:10816367

Forsdyke, D R

2000-06-01

51

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.

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

2005-01-01

52

Visual discrimination between two sexually deceptive Ophrys species by a bee pollinator.  

PubMed

Almost all species of the orchid genus Ophrys are pollinated by sexual deception. The orchids mimic the sex pheromone of receptive female insects, mainly hymenopterans, in order to attract males seeking to copulate. Most Ophrys species have achromatic flowers, but some exhibit a coloured perianth and a bright, conspicuous labellum pattern. We recently showed that the pink perianth of Ophrys heldreichii flowers increases detectability by its pollinator, males of the long-horned bee Eucera berlandi. Here we tested the hypothesis that the bright, complex labellum pattern mimics the female of the pollinator to increase attractiveness toward males. In a dual-choice test we offered E. berlandi males an O. heldreichii flower and a flower from O. dictynnae, which also exhibits a pinkish perianth but no conspicuous labellum pattern. Both flowers were housed in UV-transmitting acrylic glass boxes to exclude olfactory signals. Males significantly preferred O. heldreichii to O. dictynnae flowers. In a second experiment, we replaced the perianth of both flowers with identical artificial perianths made from pink card, so that only the labellum differed between the two flower stimuli. Males then chose between both stimuli at random, suggesting that the presence of a labellum pattern does not affect their choice. Spectral measurements revealed higher colour contrast with the background of the perianth of O. heldreichii compared to O. dictynnae, but no difference in green receptor-specific contrast or brightness. Our results show that male choice is guided by the chromatic contrast of the perianth during the initial flower approach but is not affected by the presence of a labellum pattern. Instead, we hypothesise that the labellum pattern is involved in aversive learning during post-copulatory behaviour and used by the orchid as a strategy to increase outcrossing. PMID:21516265

Streinzer, M; Ellis, T; Paulus, H F; Spaethe, J

2010-09-01

53

Molecular genetic analysis and ecological evidence reveals multiple cryptic species among thynnine wasp pollinators of sexually deceptive orchids.  

PubMed

Sexually deceptive Chiloglottis orchids lure their male thynnine wasp pollinators to the flower by emitting semiochemicals that mimic the specific sex pheromone of the wasp. Sexual deception is possible because chemical rather than visual cues play the key role in wasp mate search, suggesting that cryptic wasp species may be frequent. We investigated this prospect among Neozeleboria wasp pollinators of Chiloglottis orchids, drawing on evidence from molecular phylogenetic analysis at three genes (CO1, rhodopsin and wingless), population genetic and statistical parsimony analysis at CO1, orchid associations and their semiochemicals, and geographic ranges. We found a compelling relationship between genetically defined wasp groups, orchid associations, semiochemicals and geographic range, despite a frequent lack of detectable morphological differences. Our findings reveal multiple cryptic species among orchid pollinators and indicate that chemical changes are important for wasp reproductive isolation and speciation. The diversity of Neozeleboria may have enabled, rather than constrained, pollinator-driven speciation in these orchids. PMID:21310250

Griffiths, Kate E; Trueman, John W H; Brown, Graham R; Peakall, Rod

2011-02-15

54

Physical and Linkage Maps for Drosophila serrata, a Model Species for Studies of Clinal Adaptation and Sexual Selection  

PubMed Central

Drosophila serrata is a member of the montium group, which contains more than 98 species and until recently was considered a subgroup within the melanogaster group. This Drosophila species is an emerging model system for evolutionary quantitative genetics and has been used in studies of species borders, clinal variation and sexual selection. Despite the importance of D. serrata as a model for evolutionary research, our poor understanding of its genome remains a significant limitation. Here, we provide a first-generation gene-based linkage map and a physical map for this species. Consistent with previous studies of other drosophilids we observed strong conservation of genes within chromosome arms homologous with D. melanogaster but major differences in within-arm synteny. These resources will be a useful complement to ongoing genome sequencing efforts and QTL mapping studies in this species.

Stocker, Ann J.; Rusuwa, Bosco B.; Blacket, Mark J.; Frentiu, Francesca D.; Sullivan, Mitchell; Foley, Bradley R.; Beatson, Scott; Hoffmann, Ary A.; Chenoweth, Stephen F.

2012-01-01

55

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

56

The Evolutionary Maintenance of Sexual Reproduction: Evidence from the Ecological Distribution of Asexual Reproduction in Clonal Plants  

Microsoft Academic Search

In theory, females that reproduce asexually should enjoy a twofold advantage in fitness over sexual females, yet sex remains the predominant mode of reproduction in virtually all eukaryotes. The evolutionary maintenance of sex is especially puzzling in clonal plants because the transition from sexual to exclusively asexual reproduction is an ever-present possibility in these species. In this article, I use

Jonathan Silvertown

2008-01-01

57

Divide and broadcast: sexual reproduction in the West Indian brittle star Ophiocomella ophiactoides and its relationship to fissiparity  

Microsoft Academic Search

It is known that asexual reproduction by fission is the dominant mode of propagation in the small (disc diameter Ophiocomella ophiactoides (H. L. Clark). This species is, however, able to reproduce sexually as well. Sexual reproduction occurs throughout much or all of the year in a population of O. ophiactoides at Jamaica. Gonads are often present in recently split individuals,

P. V. Mladenov; R. H. Emson

1984-01-01

58

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

59

Social preferences based on sexual attractiveness: a female strategy to reduce male sexual attention  

PubMed Central

Male sexual harassment of females is common across sexually reproducing species and can result in fitness costs to females. We hypothesized that females can reduce unwanted male attention by constructing a social niche where their female associates are more sexually attractive than themselves, thus influencing the decision-making of males to their advantage. We tested this hypothesis in the Trinidadian guppy (Poecilia reticulata), a species with high levels of male sexual harassment. First, we confirmed that non-receptive females were harassed less when they were paired with a more sexually attractive (receptive) female than with another non-receptive female. We then found that, indeed, females exploit this as a strategy to reduce sexual harassment; non-receptive females actively preferred to associate with receptive over non-receptive females. Importantly, when given access only to chemosensory cues, non-receptive females still showed this preference, suggesting that they use information from chemical cues to assess the sexual attractiveness of potential female partners. Receptive females in contrast showed no such preferences. Our results demonstrate that females can decrease male harassment by associating with females that are more sexually attractive than themselves and that they perform active partner choices based on this relative attractiveness. We propose that this strategy is likely to represent an important pathway by which females can construct social niches that influence the decision-making of others to their advantage; in this case, to reduce the sexual harassment they experience.

Brask, Josefine B.; Croft, Darren P.; Thompson, Katharine; Dabelsteen, Torben; Darden, Safi K.

2012-01-01

60

Social preferences based on sexual attractiveness: a female strategy to reduce male sexual attention.  

PubMed

Male sexual harassment of females is common across sexually reproducing species and can result in fitness costs to females. We hypothesized that females can reduce unwanted male attention by constructing a social niche where their female associates are more sexually attractive than themselves, thus influencing the decision-making of males to their advantage. We tested this hypothesis in the Trinidadian guppy (Poecilia reticulata), a species with high levels of male sexual harassment. First, we confirmed that non-receptive females were harassed less when they were paired with a more sexually attractive (receptive) female than with another non-receptive female. We then found that, indeed, females exploit this as a strategy to reduce sexual harassment; non-receptive females actively preferred to associate with receptive over non-receptive females. Importantly, when given access only to chemosensory cues, non-receptive females still showed this preference, suggesting that they use information from chemical cues to assess the sexual attractiveness of potential female partners. Receptive females in contrast showed no such preferences. Our results demonstrate that females can decrease male harassment by associating with females that are more sexually attractive than themselves and that they perform active partner choices based on this relative attractiveness. We propose that this strategy is likely to represent an important pathway by which females can construct social niches that influence the decision-making of others to their advantage; in this case, to reduce the sexual harassment they experience. PMID:22158959

Brask, Josefine B; Croft, Darren P; Thompson, Katharine; Dabelsteen, Torben; Darden, Safi K

2011-12-07

61

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

62

Sexual disruption in a second species of wild cyprinid fish (the gudgeon, Gobio gobio) in United Kingdom freshwaters.  

PubMed

To establish whether the intersex condition seen in the roach (Rutilus rutilus) in United Kingdom (UK) rivers was species specific or a more general phenomenon in fish, evidence for sexual disruption was sought in a second cyprinid species, the gudgeon (Gobio gobio). Gudgeon were collected from the Rivers Aire and Lea (at locations that receive high-volume discharges of sewage treatment works [STW] effluent and that contain intersex roach) and from two still waters, and their gonads were examined histologically for evidence of intersexuality (the simultaneous presence of oocytes and testicular tissue). Intersex gonads were found at all sites, with the highest incidences occurring at one of the still waters (Lakeside Fisheries: 15%) and at sites on the River Aire (Thwaite Weir, Silsden Bridge, and Knostrop: 14, 13, and 12%, respectively). In the River Lea and Longton Park Lake, the incidence of intersexuality in gudgeon was 6%. In most cases, intersex gonads were characterized by a few primary oocytes/gonad section in an otherwise normal testis. However, at some sites on the River Aire (Thwaite Weir and Knostrop), the intersex condition was more severe. At Thwaite Weir, for example, more than half of the gonad in 40% of the intersex fish was comprised of ovarian tissue. Elevated concentrations of plasma vitellogenin both in male and in intersex fish indicated that fish had been exposed to estrogen(s). Some of the gudgeon were found at sites several kilometers downstream of any point discharge of STW effluent; therefore, the results likely are representative of this species in wild populations found in typical UK river ecosystems. Together with the findings in the roach, these data on the gudgeon confirm that sexual disruption in fish in UK rivers is not species specific. PMID:11764169

van Aerle, R; Nolan, T M; Jobling, S; Christiansen, L B; Sumpter, J P; Tyler, C R

2001-12-01

63

Reproducing works of Calder  

Microsoft Academic Search

Abstract Many fine art pieces have been reproduced in digital form. The digital reproductions have been used to store and transmit the original work. In contrast, mobiles, or moving sculptures, such as those designed by Alexander Calder cannot be reproduced realistically by photographs and\\/or static images. The real characteristics of mobiles come from the motions generated by interactive external forces

Dongkyoo Lee; Chang Tae Kim; Nakhoon Baek; Jong Won Lee; Kwan Woo Ryu; James K. Hahn

2001-01-01

64

Does selection on floral odor promote differentiation among populations and species of the sexually deceptive orchid genus Ophrys?  

PubMed

Sexually deceptive orchids from the genus Ophrys attract their pollinators primarily through the chemical mimicry of female hymenopteran sex pheromones, thereby deceiving males into attempted matings with the orchid labellum. Floral odor traits are crucial for the reproductive success of these pollinator-limited orchids, as well as for maintaining reproductive isolation through the attraction of specific pollinators. We tested for the signature of pollinator-mediated selection on floral odor by comparing intra and interspecific differentiation in odor compounds with that found at microsatellite markers among natural populations. Three regions from southern Italy were sampled. We found strong floral odor differentiation among allopatric populations within species, among allopatric species and among sympatric species. Population differences in odor were also reflected in significant variation in the attractivity of floral extracts to the pollinator, Colletes cunicularius. Odor compounds that are electrophysiologically active in C. cunicularius males, especially alkenes, were more strongly differentiated among conspecific populations than nonactive compounds in the floral odor. In marked contrast to these odor patterns, there was limited population or species level differentiation in microsatellites (FST range 0.005 to 0.127, mean FST 0.075). We propose that the strong odor differentiation and lack of genetic differentiation among sympatric taxa indicates selection imposed by the distinct odor preferences of different pollinating species. Within species, low FST values are suggestive of large effective population sizes and indicate that divergent selection rather than genetic drift accounts for the strong population differentiation in odor. The higher differentiation in active versus non-active odor compounds suggests that divergent selection among orchid populations may be driven by local pollinator preferences for those particular compounds critical for pollinator attraction. PMID:16153031

Mant, Jim; Peakall, Rod; Schiestl, Florian P

2005-07-01

65

A new species of Hydropisphaera, H. bambusicola, is the sexual state of Gliomastix fusigera  

Technology Transfer Automated Retrieval System (TEKTRAN)

A new species of Hydropisphaera, H. bambusicola sp. nov., is described and illustrated based on a collection from Bambusa vulgaris in Martinique. The asexual state was obtained in culture and identified as Gliomastix fusigera. Gliomastix fusigera is an anamorph species that occurs on members of the ...

66

Polyploids with Different Origins and Ancestors Form a Single Sexual Polyploid Species  

Microsoft Academic Search

Polyploidization is one of the few mechanisms that can produce instantaneous speciation. Multiple origins of tetraploid lin- eages from the same two diploid progenitors are common, but here we report the first known instance of a single tetraploid species that originated repeatedly from at least three diploid ancestors. Parallel evolution of advertisement calls in tetraploid lineages of gray tree frogs

2006-01-01

67

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

PubMed

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

2012-07-10

68

Sexual comparisons in immune ability, survival and parasite intensity in two damselfly species.  

PubMed

Recent evolutionary studies have suggested that females have a more robust immune system than males. Using two damselfly species (Hetaerina americana and Argia tezpi), we tested if females produced higher immune responses (as phenoloxidase and hydrolytic enzymes), had a higher survival (using a nylon implant inserted in the abdomen and measuring survival after 24h) and fewer parasites (gregarines and water mites) than males. We also tested whether immune differences should emerge in different body areas (thorax vs. abdomen) within each sex with the prediction that only females will differ with the abdomen having a higher immune response than their thorax since the former area, for ecological and physiological reasons, may be a target zone for increased immune investment. Animals were adults of approximately the same age. In both species, females were more immunocompetent than males, but only in H. americana females were immune responses greater in the abdomen than in the thorax. However, there were no differences in survival and parasite intensity or the probability of being parasitised between the sexes in either of the two species. Thus, this study lends partial support to the principle that females are better at defending than males despite the null difference in parasitism and survival. PMID:16843483

Córdoba-Aguilar, A; Contreras-Garduño, J; Peralta-Vázquez, H; Luna-González, A; Campa-Córdova, A I; Ascencio, F

2006-05-20

69

A quantitative genetic analysis of male sexual traits distinguishing the sibling species Drosophila simulans and D. sechellia.  

PubMed Central

A quantitative trait locus (QTL) genetic analysis of morphological and reproductive traits distinguishing the sibling species Drosophila simulans and D. sechellia was carried out in a backcross design, using 38 markers with an average spacing of 8.4 cM. The direction of QTL effects for the size of the posterior lobe was consistent across the identified QTL, indicating directional selection for this trait. Directional selection also appears to have acted on testis length, indicating that sexual selection may have influenced many reproductive traits, although other forms of directional selection cannot be ruled out. Sex comb tooth number exhibited high levels of variation both within and among isofemale lines and showed no evidence for directional selection and, therefore, may not have been involved in the early speciation process. A database search for genes associated with significant QTL revealed a set of candidate loci for posterior lobe shape and size, sex comb tooth number, testis length, tibia length, and hybrid male fertility. In particular, decapentaplegic (dpp), a gene known to influence the genital arch, was found to be associated with the largest LOD peak for posterior lobe shape and size.

Macdonald, S J; Goldstein, D B

1999-01-01

70

Case studies in reproducibility.  

PubMed

Reproducible research is a concept of providing access to data and software along with published scientific findings. By means of some case studies from different disciplines, we will illustrate reasons why readers should be given the possibility to look at the data and software independently from the authors of the original publication. We report results of a survey comprising 100 papers recently published in Bioinformatics. The main finding is that authors of this journal share a culture of making data available. However, the number of papers where source code for simulation studies or analyzes is available is still rather limited. PMID:21278369

Hothorn, Torsten; Leisch, Friedrich

2011-01-28

71

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

72

Sexual Health  

MedlinePLUS

... Exams Polycystic Ovary Syndrome Sexual Attraction and Orientation Sexual Harassment and Sexual Bullying Talking to Your Partner About ... Normal? Male Reproductive System Sexual Attraction and Orientation Sexual Harassment and Sexual Bullying Talking to Your Partner About ...

73

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.

Madjidian, Josefin A.; Lankinen, Asa

2009-01-01

74

SEXUAL ISOLATION AND COURTSHIP BEHAVIOR IN SALAMANDERS OF THE EURYCEA BISLINEATA SPECIES COMPLEX, WITH COMMENTS ON THE EVOLUTION OF THE MENTAL GLAND AND PHEROMONE DELIVERY BEHAVIOR IN THE PLETHODONTIDAE  

Microsoft Academic Search

The Eurycea bislineata (Two-lined salamander) species complex is characterized by extensive geographic genetic fragmentation throughout its range. I tested for sexual isolation and divergence in courtship behavior across a contact zone between E. wilderae and E. cirrigera. I found concordance be- tween patterns of geographic genetic fragmentation and sexual isolation that suggests that divergence in the mate-recognition systems of E.

Kenneth H. Kozak

2003-01-01

75

Recovery and succession in a multi-species tropical seagrass meadow following experimental disturbance: the role of sexual and asexual reproduction  

Microsoft Academic Search

Recolonisation and succession in a multi-species tropical seagrass meadow was examined by creating gaps (50×50 cm) in the meadow and manipulating the supply of sexual and asexual propagules. Measurements of leaf shoot density and estimates of above-ground biomass were conducted monthly to measure recovery of gaps between September 1995 and November 1997. Measurements of the seeds stored in the sediment

Michael A. Rasheed

2004-01-01

76

Reproducing in cities.  

PubMed

Reproducing in cities has always been costly, leading to lower fertility (that is, lower birth rates) in urban than in rural areas. Historically, although cities provided job opportunities, initially residents incurred the penalty of higher infant mortality, but as mortality rates fell at the end of the 19th century, European birth rates began to plummet. Fertility decline in Africa only started recently and has been dramatic in some cities. Here it is argued that both historical and evolutionary demographers are interpreting fertility declines across the globe in terms of the relative costs of child rearing, which increase to allow children to outcompete their peers. Now largely free from the fear of early death, postindustrial societies may create an environment that generates runaway parental investment, which will continue to drive fertility ever lower. PMID:18258904

Mace, Ruth

2008-02-01

77

Behavioral facilitation of reproduction in sexual and unisexual whiptail lizards.  

PubMed Central

All-female, parthenogenetic species afford a unique test of hypotheses regarding the nature and evolution of sexuality. Mating behavior accomplishes the transfer of gametes and stimulates the coordination of reproductive activity of the male and female. Cnemidophorus uniparens, a parthenogenetic species, is believed to have resulted from the hybridization of two extant gonochoristic species, Cnemidophorus inornatus and Cnemidophorus gularis. C. uniparens regularly and reliably perform behaviors identical in form to those performed during mating by male C. inornatus. We have determined experimentally that individuals of the parthenogenetic species demonstrating male-like pseudosexual behavior also share a similarity in function with males of the sexually reproducing species. The number of female C. inornatus ovulating increases, and the latency to ovulation decreases, if a sexually active conspecific male is present. A similar facilitatory effect on ovarian recrudescence occurs in the all-female C. uniparens in the presence of a male-like individual. These results show that behavioral facilitation of ovarian recrudescence is important in sexual and unisexual species. This may represent a potent selection pressure favoring the maintenance of male-typical behaviors, thus accounting for the display of behavioral traits usually associated with males in unisexual species of hybrid origin.

Crews, D; Grassman, M; Lindzey, J

1986-01-01

78

Behavioral facilitation of reproduction in sexual and unisexual whiptail lizards.  

PubMed

All-female, parthenogenetic species afford a unique test of hypotheses regarding the nature and evolution of sexuality. Mating behavior accomplishes the transfer of gametes and stimulates the coordination of reproductive activity of the male and female. Cnemidophorus uniparens, a parthenogenetic species, is believed to have resulted from the hybridization of two extant gonochoristic species, Cnemidophorus inornatus and Cnemidophorus gularis. C. uniparens regularly and reliably perform behaviors identical in form to those performed during mating by male C. inornatus. We have determined experimentally that individuals of the parthenogenetic species demonstrating male-like pseudosexual behavior also share a similarity in function with males of the sexually reproducing species. The number of female C. inornatus ovulating increases, and the latency to ovulation decreases, if a sexually active conspecific male is present. A similar facilitatory effect on ovarian recrudescence occurs in the all-female C. uniparens in the presence of a male-like individual. These results show that behavioral facilitation of ovarian recrudescence is important in sexual and unisexual species. This may represent a potent selection pressure favoring the maintenance of male-typical behaviors, thus accounting for the display of behavioral traits usually associated with males in unisexual species of hybrid origin. PMID:3467325

Crews, D; Grassman, M; Lindzey, J

1986-12-01

79

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

80

Spatial distribution and reproductive phenology of sexual and asexual Mastocarpus papillatus (Rhodophyta)  

PubMed Central

Species of the genus Mastocarpus exhibit two distinct life cycles, a sexual alternation of generations and an obligate, asexual direct life cycle that produces only female upright fronds. In the intertidal red alga, M. papillatus (Kützing) sexual fronds dominate southern populations and asexual fronds dominate northern populations along the northeast Pacific coast, a pattern of spatial separation called geographic parthenogenesis. Along the central coast of California, sexual and asexual variants occur in mixed populations, but it is not known whether they are spatially separated within the intertidal zone at a given site. We investigated reproductive phenologies and analyzed patterns of spatial distributions of sexual and asexual M. papillatus at three sites in this region. Sexual M. papillatus were aggregated lower on the shore at two sites and only reproduced during part of a year, while asexual M. papillatus occurred throughout the intertidal range at all sites and reproduced throughout the year. The distribution patterns of sexual and asexual M. papillatus are consistent with a hypothesis of shoreline topography influencing their dynamics of dispersal and colonization. Spatial and temporal partitioning may contribute to the long-term coexistence of sexual and asexual life histories in this, and other, species of Mastocarpus. The occurrence of geographic parthenogenesis at multiple spatial scales in M. papillatus provides an opportunity to gain insight into the phenomenon.

Fierst, Janna L.; Kubler, Janet E.; Dudgeon, Steven R.

2010-01-01

81

Correlation between Anolis lizard dewlap phenotype and environmental variation indicates adaptive divergence of a signal important to sexual selection and species recognition.  

PubMed

Although the importance of signals involved in species recognition and sexual selection to speciation is widely recognized, the processes that underlie signal divergence are still a matter of debate. Several possible processes have been hypothesized, including genetic drift, arbitrary sexual selection, and adaptation to local signaling environments. We use comparative analyses to investigate whether the remarkable geographic variation of dewlap phenotype in a Hispaniolan trunk Anolis lizard (A. distichus) is a result of adaptive signal divergence to heterogeneous environments. We recover a repeated pattern of divergence in A. distichus dewlap color, pattern, and size with environmental variation across Hispaniola. These results are aligned with ecological models of signal divergence and provide strong evidence for dewlap adaptation to local signaling environments. We also find that A. distichus dewlaps vary with the environment in a different manner to other previously studied anoles, thus expanding upon previous predictions on the direction dewlaps will diverge in perceptual color space in response to the environment. PMID:23356628

Ng, Julienne; Landeen, Emily L; Logsdon, Ryane M; Glor, Richard E

2012-10-10

82

Increased vigilance of paired males in sexually dimorphic species: distinguishing between alternative explanations in wintering Eurasian wigeon  

Microsoft Academic Search

In animal pairs, males are often more vigilant than females. This is generally assumed to result from mate guarding (either against predators or other males). However, when males have conspicuous secondary sexual characteristics, they could be constrained to be more vigilant because of a higher predation risk than females. We attempted to distinguish between the \\

Matthieu Guillemain; Richard W. G. Caldow; Kathy H. Hodder; John D. Goss-Custard

2003-01-01

83

Positive feedback in the transition from sexual reproduction to parthenogenesis  

PubMed Central

Understanding how new phenotypes evolve is challenging because intermediate stages in transitions from ancestral to derived phenotypes often remain elusive. Here we describe and evaluate a new mechanism facilitating the transition from sexual reproduction to parthenogenesis. In many sexually reproducing species, a small proportion of unfertilized eggs can hatch spontaneously (‘tychoparthenogenesis’) and develop into females. Using an analytical model, we show that if females are mate-limited, tychoparthenogenesis can result in the loss of males through a positive feedback mechanism whereby tychoparthenogenesis generates female-biased sex ratios and increasing mate limitation. As a result, the strength of selection for tychoparthenogenesis increases in concert with the proportion of tychoparthenogenetic offspring in the sexual population. We then tested the hypothesis that mate limitation selects for tychoparthenogenesis and generates female-biased sex ratios, using data from natural populations of sexually reproducing Timema stick insects. Across 41 populations, both the tychoparthenogenesis rates and the proportions of females increased exponentially as the density of individuals decreased, consistent with the idea that low densities of individuals result in mate limitation and selection for reproductive insurance through tychoparthenogenesis. Our model and data from Timema populations provide evidence for a simple mechanism through which parthenogenesis can evolve rapidly in a sexual population.

Schwander, Tanja; Vuilleumier, Severine; Dubman, Janie; Crespi, Bernard J.

2010-01-01

84

Variation in social and sexual behaviour in four species of aposematic seed bugs (Hemiptera: Lygaeidae): The role of toxic and non-toxic food.  

PubMed

Understanding variation in social behaviour both within and among species continues to be a challenge. Evolutionary or ecological theory typically predicts the optimal behaviour for an animal under a given set of circumstances, yet the real world presents much greater variation in behaviour than predicted. This variation is apparent in many social and sexual interactions, including mate choice, and has led to a renewed focus on individual variation in behaviour. Here we explore within and among species variation in social behaviour in four species of aposematic seed bug (Lygaeidae: Hemiptera). These species are Müllerian mimics, with characteristic warning colouration advertising their chemical toxicity. We examine the role of diet in generating variation in two key behaviours: social aggregation of nymphs and mate choice. We test how behaviour varies with exposure to either milkweed (a source of defensive compounds) or sunflower (that provides no defence). We show that although the four species vary in their food preferences, and diet influences their life-history (as highlighted by body size), social aggregation and mate choice is relatively unaffected by diet. We discuss our findings in terms of the evolution of aposematism, the importance of automimicry, and the role of diet in generating behavioural variation. PMID:23796773

Burdfield-Steel, Emily R; Dougherty, Liam R; Smith, Lynsey A; Collins, Laura A; Shuker, David M

2013-06-21

85

Innate sexuality determines the mechanisms of telomere maintenance.  

PubMed

Recently, telomere length has been shown to be differentially regulated in asexually and sexually reproducing planarians. In addition, it was found that asexual worms maintain telomere length somatically during reproduction by fission or when regeneration is induced by amputation, whereas sexual worms only achieve telomere elongation through sexual reproduction. We have established an experimental bioassay system to induce switching from asexual to sexual reproduction in planarians, that is, sexualization. In this study, the relationship between the reproductive mode and telomere maintenance was investigated using innate asexually reproducing worms, innate sexually reproducing worms, and experimentally sexualized worms. Here, we show that innate asexual planarians maintain telomere length during cell division and that innate sexual planarians exhibit telomere shortening. However, experimental sexualized worms maintain telomere length during cell division. These results indicate that innate sexuality is linked to the mechanism of telomere maintenance. PMID:23319366

Tasaka, Kenta; Yokoyama, Naoki; Nodono, Hanae; Hoshi, Motonori; Matsumoto, Midori

2013-01-01

86

Relevance of unilateral and bilateral sexual polyploidization in relation to intergenomic recombination and introgression in Lilium species hybrids  

Microsoft Academic Search

Sexual polyploids were induced in diploid (2n = 2x = 24) interspecific F1 hybrids of Longiflorum × Asiatic (LA) and Oriental × Asiatic (OA) Lilium hybrids by backcrossing to Asiatic (AA) parents as well as by sib-mating of the F1 LA hybrids. A majority of the BC1 progenies\\u000a were triploid and the progenies from sib-mating were tetraploid or near tetraploids. Genomic in situ hybridization (GISH)\\u000a technique was applied

Nadeem Khan; Rodrigo Barba-Gonzalez; M. S. Ramanna; Paul Arens; Richard G. F. Visser; Jaap M. Van Tuyl

2010-01-01

87

Sexual Health  

MedlinePLUS

... experiences, free of coercion, discrimination and violence. [1] Sexual Health News & Information HHS Statement on LGBT Health Awareness ... infectious diseases, reproductive health and sexual violence prevention. Sexual Health Topics Sexually Transmitted Diseases Up-to-date information ...

88

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

2012-08-01

89

Non-coding RNAs in mammalian sexual development.  

PubMed

The present decade is witnessing a paradigm shift in our understanding of gene regulation. RNA, once relegated to an intermediary between DNA and protein, has emerged as a key contributor in the coordination of complex developmental pathways. For sexually reproducing organisms, propagation of the species is accomplished via an elaborate sexual phenotype. In mammals this consists of a highly complex cell lineage that has the capacity for intricate self-differentiation whilst maintaining the potential to generate all cell types upon fertilization. In addition, mammals possess a diverse range of somatic reproductive tissues and organs that often undergo dynamic morphological changes in response to a variety of external and internal cues. Although the protein component required to mediate these processes continues to be vigorously investigated, it is becoming increasingly apparent that an understanding of the non-coding RNA (ncRNA) component is required to develop a comprehensive picture of mammalian sexual development. PMID:20197714

McFarlane, L; Wilhelm, D

2010-02-23

90

Running a reproducible plasma process  

SciTech Connect

Although plasma processing has become an indispensable part of modern integrated circuit fabrication, and modern plasma processing equipment has become sophisticated, it is still not a simple matter to run a reproducible plasma process.

Chapman, B.; Gray, D.E. (Lucas Laboratories, San Jose, CA 95131 (USA))

1990-02-05

91

Species differences in estrogen receptor and progesterone receptor-mRNA expression in the brain of sexual and unisexual whiptail lizards.  

PubMed

Circulating concentrations of gonadal steroid hormones and reproductive behavior in female vertebrates vary as a function of ovarian state. Steroids secreted by the ovary, specifically estrogen and progesterone, influence the expression of behaviors associated with reproduction by intracellular sex steroid receptors located in specific regions of the brain. Using in situ hybridization, we analyzed estrogen receptor and progesterone receptor messenger RNA expression in several brain regions of ovariectomized, vitellogenic, and postovulatory individuals from two species of whiptail lizards (Cnemidophorus uniparens and C. inornatus). Although these species are genetically very similar, they differ in two aspects of their reproductive biology: (i) the unisexual C. uniparens alternate between expressing female-typical and male-like pseudosexual behaviors while female C. inornatus normally express only female receptive behavior, and (ii) circulating estradiol concentrations in reproductively active female C. uniparens are approximately five-fold lower than in reproductively active female C. inornatus. We found that the regulation of sex steroid receptor gene expression was region specific, with receptor-mRNA expression being increased, unchanged, or decreased during vitellogenesis depending on the area. Furthermore, several species differences in the amount of sex steroid receptor-mRNA were found that may be relevant to the species differences in circulating estrogen concentrations and sexual behavior. PMID:7496397

Young, L J; Nag, P K; Crews, D

1995-07-01

92

Aspects of sexual reproduction in Mycosphaerella species on wheat and barley : genetic studies on specificity, mapping, and fungicide resistance  

Microsoft Academic Search

Mycosphaerella species are haploid ascomycetes that cause major economic losses in crops that include cereals, citrus fruits, and bananas, among others. Two organisms in this genus are Mycosphaerella graminicola (Fuckel) .I. Schröt (anamorph Sepioria tritici) and Septoriapasserinii. M graminicola is the causal agent of septoria tritici blotch of both bread wheat and durum wheat species, and S. passerinii causes septoria

S. B. Ware

2006-01-01

93

Sexual reproduction in three hermaphroditic deep-sea Caryophyllia species (Anthozoa: Scleractinia) from the NE Atlantic Ocean  

NASA Astrophysics Data System (ADS)

The reproductive biology and gametogenesis of three species of Caryophyllia were examined using histological techniques. Caryophyllia ambrosia, Alcock 1898, C. cornuformis, Pourtales 1868, and C. sequenzae, Duncan 1873, were collected from the Porcupine Seabight and Rockall Trough in the NE Atlantic Ocean. These three ahermatypic solitary corals inhabit different depth ranges: C. cornuformis - 435-2000 m, C. sequenzae - 960-1900 m, and C. ambrosia - 1100-3000 m. All three species are hermaphroditic. Hermaphroditism in these species was found to be cyclical, with only one sex of gametes viable in any individual at any point in time, although gametes of both sexes were found together within a single mesentery. Once the viable gametes are spawned, the next sex of gametes continues to grow until mature, and so gametogenesis is a continuous cycle. Oocytes and spermacysts in all species increased in density towards the actinopharynx. Maximum fecundity for C. sequenzae was 940 oocytes per polyp, and for C. ambrosia 2900 oocytes per polyp. Fecundity could not be established for C. cornuformis. In all three species, individuals were asynchronous within populations, and production of gametes was quasi-continuous throughout the year. All species are hypothesised to have lecithotrophic larvae owing to their large oocyte sizes ( C. cornuformis max - 350 ?m; C. sequenzae max - 430 ?m; C. ambrosia max - 700 ?m). Both the average oocyte size and fecundity increased in species going down the depth gradient of the NE Atlantic.

Waller, Rhian G.; Tyler, Paul A.; Gage, John D.

2005-12-01

94

How can sexual selection promote population divergence?  

Microsoft Academic Search

Sexual selection is a competition between conspecific individuals to acquire mates and maximize their reproductive success. This can lead to the development of conspicuous secondary sexual traits under several possible mechanisms. Since these sexual characters can be used as potential discriminant features in species recognition, it seems legitimate to think of a potential role of sexual selection in population divergence.

Sophie Questiau

1999-01-01

95

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.

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

2012-01-01

96

Genetic diversity in populations of asexual and sexual bag worm moths (Lepidoptera: Psychidae)  

PubMed Central

Background Despite the two-fold cost of sex, most of the higher animals reproduce sexually. The advantage of sex has been suggested to be its ability, through recombination, to generate greater genetic diversity than asexuality, thus enhancing adaptation in a changing environment. We studied the genetic diversity and the population structure of three closely related species of bag worm moths: two strictly sexual (Dahlica charlottae and Siederia rupicolella) and one strictly asexual (D. fennicella). These species compete for the same resources and share the same parasitoids. Results Allelic richness was comparable between the sexual species but it was higher than in the asexual species. All species showed high heterozygote deficiency and a large variation was observed among FIS values across loci and populations. Large genetic differentiation was observed between populations confirming the poor dispersal ability of these species. The asexual species showed lower genotype diversity than the sexual species. Nevertheless, genotype diversity was high in all asexual populations. Conclusion The three different species show a similar population structure characterised by high genetic differentiation among populations and low dispersal. Most of the populations showed high heterozygote deficiency likely due to the presence of null alleles at most of the loci and/or to the Wahlund effect. Although the parthenogenetic D. fennicella shows reduced genetic diversity compared to the sexual species, it still shows surprisingly high genotype diversity. While we can not totally rule out the presence of cryptic sex, would explain this high genotype diversity, we never observed sex in the parthenogenetic D. fennicella, nor was there any other evidence of this. Alternatively, a non-clonal parthenogenetic reproduction, such as automictic thelytoky, could explain the high genotypic diversity observed in D. fennicella.

Grapputo, Alessandro; Kumpulainen, Tomi; Mappes, Johanna; Parri, Silja

2005-01-01

97

SEXUAL DIMORPHISM AND FOOD HABITS IN THREE  

Microsoft Academic Search

studies on weight, wing area, and skeletal proportions of these three species (Storer, 1955), it became apparent that although the females of all three species average larger than the males, the sexual difference in size was greatest in the smallest species, the Sharp-shinned Hawk, and least in the largest species, the Goshawk. To determine more precisely the degree of sexual

98

Layered sexual selection: a comparative analysis of sexual behaviour within an assemblage of piophilid flies  

Microsoft Academic Search

Although many theoretical and empirical studies have addressed the dynamics of sexual selection, little is known about the evolution of multiple sexual-selection mechanisms within the same system. I performed a qualitative comparative study of sexual behaviours in seven sympatric species of piophilid flies to identify and compare the appar - ent mechanisms of sexual selection operating in each system. In

Russell Bonduriansky

2003-01-01

99

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.

Kernaleguen, Laetitia; Cazelles, Bernard; Arnould, John P. Y.; Richard, Pierre; Guinet, Christophe; Cherel, Yves

2012-01-01

100

Sexual Health  

MedlinePLUS

Sexual health Basics In-Depth Multimedia Expert Answers Resources What's New Sexual health By Mayo Clinic staff Original Article: http://www. ... not share your e-mail address Sign up Sexual health basics Sexuality is part of being human. Love, ...

101

Sexual Harassment.  

ERIC Educational Resources Information Center

|This paper sets out the legal grounds for sexual harassment claims in education settings, and notes a number of pertinent cases that are illustrative of common legal and factual issues. Sexual harassment, including sexual abuse, is prohibited by federal and state statutes. Sexual harassment in the context of employment constitutes employment…

Uerling, Donald F.

102

Quantizations from reproducing kernel spaces  

NASA Astrophysics Data System (ADS)

The purpose of this work is to explore the existence and properties of reproducing kernel Hilbert subspaces of L2(C,d2z/?) 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.

Twareque Ali, S.; Bagarello, F.; Pierre Gazeau, Jean

2012-05-01

103

Sexual Reproduction in Ferns  

Microsoft Academic Search

\\u000a This work summarizes the mechanisms involved in sexual reproduction in the gametophyte of pteridophyta, which is selected\\u000a as experimental system due to its morphological simplicity, and the lack of connections with the mother plant.\\u000a \\u000a \\u000a A better knowledge about the mechanisms involved in sexual reproduction has important repercussions in the plant world, and\\u000a could contribute to exploiting ­interesting species in a

V. Menéndez; E. Peredo; M. Méndez; A. Revilla; H. Fernández

104

Sexual Selection and Speciation  

Microsoft Academic Search

Abstract Sexual selection has a reputation as a major cause of speciation, one of the most potent forces driving reproductive,isolation. This rep- utation arises from,observations,that species differ most,in traits involved with mating,success and from,successful models,of sexual selection–driven speciation. But how,well proven is the case? Models confirm that the process can occur, but is strongest in conjunction with ecological or niche

Michael G. Ritchie

2007-01-01

105

Rare gene capture in predominantly androgenetic species  

PubMed Central

The long-term persistence of completely asexual species is unexpected. Although asexuality has short-term evolutionary advantages, a lack of genetic recombination leads to the accumulation over time of deleterious mutations. The loss of individual fitness as a result of accumulated deleterious mutations is expected to lead to reduced population fitness and possible lineage extinction. Persistent lineages of asexual, all-female clones (parthenogenetic and gynogenetic species) avoid the negative effects of asexual reproduction through the production of rare males, or otherwise exhibit some degree of genetic recombination. Another form of asexuality, known as androgenesis, results in offspring that are clones of the male parent. Several species of the Asian clam genus Corbicula reproduce via androgenesis. We compared gene trees of mitochondrial and nuclear loci from multiple sexual and androgenetic species across the global distribution of Corbicula to test the hypothesis of long-term clonality of the androgenetic species. Our results indicate that low levels of genetic capture of maternal nuclear DNA from other species occur within otherwise androgenetic lineages of Corbicula. The rare capture of genetic material from other species may allow androgenetic lineages of Corbicula to mitigate the effects of deleterious mutation accumulation and increase potentially adaptive variation. Models comparing the relative advantages and disadvantages of sexual and asexual reproduction should consider the possibility of rare genetic recombination, because such events seem to be nearly ubiquitous among otherwise asexual species.

Hedtke, Shannon M.; Glaubrecht, Matthias; Hillis, David M.

2011-01-01

106

Rare gene capture in predominantly androgenetic species.  

PubMed

The long-term persistence of completely asexual species is unexpected. Although asexuality has short-term evolutionary advantages, a lack of genetic recombination leads to the accumulation over time of deleterious mutations. The loss of individual fitness as a result of accumulated deleterious mutations is expected to lead to reduced population fitness and possible lineage extinction. Persistent lineages of asexual, all-female clones (parthenogenetic and gynogenetic species) avoid the negative effects of asexual reproduction through the production of rare males, or otherwise exhibit some degree of genetic recombination. Another form of asexuality, known as androgenesis, results in offspring that are clones of the male parent. Several species of the Asian clam genus Corbicula reproduce via androgenesis. We compared gene trees of mitochondrial and nuclear loci from multiple sexual and androgenetic species across the global distribution of Corbicula to test the hypothesis of long-term clonality of the androgenetic species. Our results indicate that low levels of genetic capture of maternal nuclear DNA from other species occur within otherwise androgenetic lineages of Corbicula. The rare capture of genetic material from other species may allow androgenetic lineages of Corbicula to mitigate the effects of deleterious mutation accumulation and increase potentially adaptive variation. Models comparing the relative advantages and disadvantages of sexual and asexual reproduction should consider the possibility of rare genetic recombination, because such events seem to be nearly ubiquitous among otherwise asexual species. PMID:21606355

Hedtke, Shannon M; Glaubrecht, Matthias; Hillis, David M

2011-05-23

107

Haldane's Rule by Sexual Transformation in Caenorhabditis  

Microsoft Academic Search

Haldane's rule in C. briggsae C. remanei broods was caused by sexual transformation; XX and XO hybrids were female. C. briggsae and C. remanei variants that partially suppress hybrid sexual transformation were identified. Effects of variant strains were cumulative. Hence, aberrant sex determination is a reproduc- tive isolation mechanism in Caenorhabditis.

Scott Everet Baird

2002-01-01

108

Mating system, sexual dimorphism, and the opportunity for sexual selection in a territorial ungulate  

Microsoft Academic Search

In mammals, species with high sexual size dimorphism tend to have highly polygynous mating systems associated with high variance in male lifetime reproductive success (LRS), leading to a high opportunity for sexual selection. However, little in- formation is available for species with weak sexual size dimorphism. In a long-term study population, we used parentage analysis based on 21 microsatellite markers

Cecile Vanpe; Petter Kjellander; M. Galan; J.-F. Cosson; S. Aulagnier; O. Liberg; A. J. M. Hewison

2007-01-01

109

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

PubMed

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

2009-10-07

110

The influence of temperature and host availability on the host exploitation strategies of sexual and asexual parasitic wasps of the same species  

Microsoft Academic Search

In the hymenopteran parasitoid Venturia canescens, asexual (obligate thelytoky not induced by Wolbachia bacteria) and sexual (arrhenotokous) wasps coexist in field conditions despite the demographic cost incurred due to the production of males by sexual females. Arrhenotoky predominates in field conditions, whereas populations in indoor conditions (mills, granaries) are exclusively thelytokous. These differences in the relative abundance of the two

Isabelle Amat; Marcela Castelo; Emmanuel Desouhant; Carlos Bernstein

2006-01-01

111

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

112

Observable and reproducible rogue waves  

NASA Astrophysics Data System (ADS)

In physical regimes described by the cubic, focusing, nonlinear Schrödinger (NLS) equation, the N-dimensional homoclinic orbits of a constant amplitude wave with N unstable modes appear to be good candidates for experimentally observable and reproducible rogue waves. These homoclinic solutions include the Akhmediev breathers (N = 1), which are among the most widely adopted spatially periodic models of rogue waves, and their multi-mode generalizations (N > 1), and will be referred to as multi-mode breathers. Numerical simulations and a linear stability analysis indicate that the breathers with a maximal number of modes (maximal breathers) are robust with respect to rather general perturbations of the initial data in a neighborhood of the unstable background. ).

Calini, A.; Schober, C. M.

2013-10-01

113

Evaluation of guidewire path reproducibility  

PubMed Central

The number of minimally invasive vascular interventions is increasing. In these interventions, a variety of devices are directed to and placed at the site of intervention. The device used in almost all of these interventions is the guidewire, acting as a monorail for all devices which are delivered to the intervention site. However, even with the guidewire in place, clinicians still experience difficulties during the interventions. As a first step toward understanding these difficulties and facilitating guidewire and device guidance, we have investigated the reproducibility of the final paths of the guidewire in vessel phantom models on different factors: user, materials and geometry. Three vessel phantoms (vessel diameters ?4 mm) were constructed having tortuousity similar to the internal carotid artery from silicon tubing and encased in Sylgard elastomer. Several trained users repeatedly passed two guidewires of different flexibility through the phantoms under pulsatile flow conditions. After the guidewire had been placed, rotational c-arm image sequences were acquired (9 in. II mode, 0.185 mm pixel size), and the phantom and guidewire were reconstructed (5123, 0.288 mm voxel size). The reconstructed volumes were aligned. The centerlines of the guidewire and the phantom vessel were then determined using region-growing techniques. Guidewire paths appear similar across users but not across materials. The average root mean square difference of the repeated placement was 0.17±0.02 mm (plastic-coated guidewire), 0.73±0.55 mm (steel guidewire) and 1.15±0.65 mm (steel versus plastic-coated). For a given guidewire, these results indicate that the guidewire path is relatively reproducible in shape and position.

Schafer, Sebastian; Hoffmann, Kenneth R.; Noel, Peter B.; Ionita, Ciprian N.; Dmochowski, Jacek

2008-01-01

114

Evaluation of guidewire path reproducibility.  

PubMed

The number of minimally invasive vascular interventions is increasing. In these interventions, a variety of devices are directed to and placed at the site of intervention. The device used in almost all of these interventions is the guidewire, acting as a monorail for all devices which are delivered to the intervention site. However, even with the guidewire in place, clinicians still experience difficulties during the interventions. As a first step toward understanding these difficulties and facilitating guidewire and device guidance, we have investigated the reproducibility of the final paths of the guidewire in vessel phantom models on different factors: user, materials and geometry. Three vessel phantoms (vessel diameters approximately 4 mm) were constructed having tortuousity similar to the internal carotid artery from silicon tubing and encased in Sylgard elastomer. Several trained users repeatedly passed two guidewires of different flexibility through the phantoms under pulsatile flow conditions. After the guidewire had been placed, rotational c-arm image sequences were acquired (9 in. II mode, 0.185 mm pixel size), and the phantom and guidewire were reconstructed (512(3), 0.288 mm voxel size). The reconstructed volumes were aligned. The centerlines of the guidewire and the phantom vessel were then determined using region-growing techniques. Guidewire paths appear similar across users but not across materials. The average root mean square difference of the repeated placement was 0.17 +/- 0.02 mm (plastic-coated guidewire), 0.73 +/- 0.55 mm (steel guidewire) and 1.15 +/- 0.65 mm (steel versus plastic-coated). For a given guidewire, these results indicate that the guidewire path is relatively reproducible in shape and position. PMID:18561663

Schafer, Sebastian; Hoffmann, Kenneth R; Noël, Peter B; Ionita, Ciprian N; Dmochowski, Jacek

2008-05-01

115

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

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

In vitro rejuvenation of woody species.  

PubMed

Juvenility and phase change in woody plant species exert profound impacts on plant morphology and the ability of explants to be successfully propagated in vitro. Morphological characteristics such as leaf shape modifications, thorniness, and the inability to initiate flowers are associated with juvenility. Physiological maturity, that is the ability to reproduce sexually, is reached by many woody species only after many years of juvenile growth. As a result, micropropagation of woody species has historically been difficult with many plant species proving to be exceedingly recalcitrant. The importance of juvenility and its impact on successful vegetative reproduction in vitro has therefore received much research attention. In vitro technologies that have been demonstrated to induce rejuvenation include meristem culture, chemical treatments, pruning and hedging, forcing new growth, and taking advantage of epicormic buds, grafting and micrografting, and somatic embryogenesis. Applications of these technologies are discussed in this chapter. PMID:23179715

Read, Paul E; Bavougian, Christina M

2013-01-01

118

Sexual Health  

MedlinePLUS

... can affect the ability to have or enjoy sex in both men and women. Concerns about infertility ... addition, a number of diseases and disorders affect sexual health. These include sexually transmitted diseases and cancer. In ...

119

7 CFR 800.166 - Reproducing certificates.  

Code of Federal Regulations, 2013 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)...

2013-01-01

120

The kin structure of sexual interactions  

PubMed Central

The origin of sexual reproduction involved the evolution of zygotes from separate genomes and, like other social processes, should therefore be amenable to analysis using kin selection theory. I consider how kin structure affects sexual interactions in three contexts—the evolution of sexual reproduction, sex allocation and sexual conflict. Kin structure helps explain the even-handed replication of paternal and maternal genes under outbreeding. Under inbreeding, it predicts altruistic failure to replicate by one half of the diploid genome. Kin structure predicts optimal sex ratios and potential conflicts over sex ratio within social groups and individuals. Sexual conflict predictably occurs as a function of (i) the probability that current sexual partners will reproduce together in future and (ii) between-partner relatedness. I conclude that systematically analysing the kin structure of sexual interactions helps illuminate their evolution.

Bourke, A. F. G.

2009-01-01

121

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

122

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.

2010-01-01

123

Generalized multiple scale reproducing kernel particle methods  

Microsoft Academic Search

An approach to unify reproducing kernel methods under one large umbrella and an extension to include time and spatial shifting are proposed. The study is divided into three major topics. The groundwork is set by revisiting the Fourier analysis of discrete systems. The multiresolution concept and its significance in devising the reproducing kernel methods and its discrete counterpart, reproducing kernel

Wing Kam Liu; Yijung Chen; R. Aziz Uras; Chin Tang Chang

1996-01-01

124

Loss of Sexual Reproduction and Dwarfing in a Small Metazoan  

PubMed Central

Background Asexuality has major theoretical advantages over sexual reproduction, yet newly formed asexual lineages rarely endure. The success, or failure, of such lineages is affected by their mechanism of origin, because it determines their initial genetic makeup and variability. Most previously described mechanisms imply that asexual lineages are randomly frozen subsamples of a sexual population. Methodology/Principal Findings We found that transitions to obligate parthenogenesis (OP) in the rotifer Brachionus calyciflorus, a small freshwater invertebrate which normally reproduces by cyclical parthenogenesis, were controlled by a simple Mendelian inheritance. Pedigree analysis suggested that obligate parthenogens were homozygous for a recessive allele, which caused inability to respond to the chemical signals that normally induce sexual reproduction in this species. Alternative mechanisms, such as ploidy changes, could be ruled out on the basis of flow cytometric measurements and genetic marker analysis. Interestingly, obligate parthenogens were also dwarfs (approximately 50% smaller than cyclical parthenogens), indicating pleiotropy or linkage with genes that strongly affect body size. We found no adverse effects of OP on survival or fecundity. Conclusions/Significance This mechanism of inheritance implies that genes causing OP may evolve within sexual populations and remain undetected in the heterozygous state long before they get frequent enough to actually cause a transition to asexual reproduction. In this process, genetic variation at other loci might become linked to OP genes, leading to non-random associations between asexuality and other phenotypic traits.

Stelzer, Claus-Peter; Schmidt, Johanna; Wiedlroither, Anneliese; Riss, Simone

2010-01-01

125

Challenging Discourse Themes Reproducing Gender in Heterosexual Dating: An Analog Study  

Microsoft Academic Search

Societal discourses tied to gender play apowerful role in shaping ideas and views about normalsexual experience. This study investigated whether“male sexual drive” discourse themes inheterosexual dating could be reproduced in a laboratorysetting, and whether these themes could be disrupted bymeans of a laboratory intervention. Young, single,heterosexual adults, most of whom were Caucasian and middle class, role played a series of

Lucia Albino Gilbert; Sarah J. Walker; Sherry McKinney; Jessica L. Snell

1999-01-01

126

Geographical parthenogenesis, genome size variation and pollen production in the arctic-alpine species Hieracium alpinum  

Microsoft Academic Search

Hieracium alpinum L. (Asteraceae) is an arctic-alpine species distributed throughout Europe with both diploid and triploid cytotypes. We determined\\u000a the ploidy levels of plants from 23 populations from Austria, Bosnia and Herzegovina, Finland, Italy, Norway, Romania, Slovakia,\\u000a Switzerland and Ukraine. Data showed a non-overlapping pattern of cytotype distribution: sexually reproducing diploids (2n = 2x = 18) occur solely in the Eastern and Southern Carpathians,

Patrik Mráz; Jind?ich Chrtek; Barbora Šingliarová

2009-01-01

127

Sexually selected females in the monogamous Western Australian seahorse  

Microsoft Academic Search

Studies of sexual selection in monogamous species have hitherto focused on sexual selection among males. Here, we provide empirical documentation that sexual selection can also act strongly on females in a natural population with a monogamous mating system. In our field-based genetic study of the monogamous Western Australian seahorse, Hippocampus subelongatus, sexual selection differentials and gradients show that females are

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

2007-01-01

128

Natural Hybridization between the Cholla Cactus Species Opuntia spinosior and Opuntia versicolor  

PubMed Central

The sexually reproducing cholla cactus species, Opuntia spinosior and O. versicolor, hybridize naturally in Arizona to produce hybrid swarms and segregating introgressive populations with a high degree of individual variation. The pattern of variation in these hybrid populations can be compared with that in populations derived from crossing of O. spinosior and O. fulgida, where the hybrids reproduce vegetatively rather than by seeds. The latter hybrid combination, in marked contrast to the former, results in clonal colonies with little or no observable individual variation. Images

Grant, Verne; Grant, Karen A.

1971-01-01

129

Sexual reproduction of the pentaploid, short-styled Oxalis pes-caprae allows the production of viable offspring.  

PubMed

Reproduction is a key factor for the successful establishment and spread of introduced species. Oxalis pes-caprae is a tristylous species with a self- and morph-incompatibility sexual system that, in the invaded range of the western Mediterranean Basin, has been found to reproduce asexually because only the pentaploid, short-styled morph (5x S-morph) was introduced. The objective of this study was to test the ability of the 5x S-morph of O. pes-caprae to produce viable offspring in the absence of compatible mates, exploring the hypothesis that new morphs could have emerged by sexual reproduction events of the initially introduced morph. Pollen germination, pollen tube development, fruit and seed production, seed germination and offspring ploidy levels were analysed after controlled hand-pollinations to assess self- and morph-incompatibility and production of viable gametes by the 5x S-morph. The self-incompatibility system is still operating, but a partial breakdown in the morph-incompatibility system combined with the production of viable gametes was observed, allowing sexual reproduction of the 5x S-morph in the invaded range. The ability of the 5x S-morph to reproduce sexually may have major consequences for the dynamics of invasive populations of O. pes-caprae and could be one of the factors involved in the occurrence of new floral morphs in this invaded range. PMID:23594049

Costa, J; Ferrero, V; Loureiro, J; Castro, M; Navarro, L; Castro, S

2013-04-17

130

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.

Ropars, Jeanne; Dupont, Joelle; Fontanillas, Eric; Rodriguez de la Vega, Ricardo C.; Malagnac, Fabienne; Coton, Monika; Giraud, Tatiana; Lopez-Villavicencio, Manuela

2012-01-01

131

Understanding Sexuality  

Microsoft Academic Search

\\u000a Chapter 3 provides readers with an explanation of the issues related to sexuality in schools. The first section defines sexual\\u000a orientation, behavior, and identity and several related terms that are important for education professionals to understand.\\u000a The second section explores contemporary youth sexualities and some of the various identities embraced by youth today. The\\u000a third section gives a brief history

Elizabeth J. Meyer

132

Sexual addictions.  

PubMed

The potential adverse consequences, personal distress, shame and guilt presented by patients who suffer from sexual addiction require a more in-depth understanding of the phenomenology and psychobiology of this disorder. Methods: A bibliographic review was conducted using MEDLINE and EBSCO databases with the following keywords: "sexual addiction," "hypersexuality," "compulsive sexual behavior," "behavioural addiction," "treatment," and "addiction." Results: Several conceptualizations of excessive nonparaphilic sexual disorder have been proposed based on the models of, respectively, obsessive compulsive disorder, impulse control disorder, out of control excessive sexual disorder, and addictive disorder. Despite the lack of robust scientific data, a number of clinical elements, such as the frequent preoccupation with this type of behavior, the time spent in sexual activities, the continuation of this behavior despite its negative consequences, the repeated and unsuccessful efforts made to reduce the behavior, are in favor of an addictive disorder. In addition there is a high comorbidity between excessive sexual behavior and other addictive behaviors. Conclusion: The phenomenology of excessive nonparaphilic sexual disorder favors its conceptualization as an addictive behavior, rather than an obsessive-compulsive, or an impulse control disorder. Moreover, the criteria that are quite close to those of addictive disorders were recently proposed for the future DSM-V in order to improve the characterization of this condition. Finally, controlled studies are warranted in order to establish clear guidelines for treatment of sexual addiction. PMID:20666699

Garcia, Frederico Duarte; Thibaut, Florence

2010-09-01

133

Juvenile hormone mediates sexual dimorphism in horned beetles  

Microsoft Academic Search

The causes and consequences of sexual dimorphism are major themes in biology. Here we explore the endocrine regulation of sexual dimorphism in horned beetles. Specifically, we explore the role of juvenile hormone (JH) in regulating horn expression in females of two species with regular sexual dimorphism for pronotal horns (females have much shorter horns than males) and a third species

J. Andrew Shelby; Richard Madewell; Armin P. Moczek

2007-01-01

134

Military Sexual Trauma  

MedlinePLUS

... to experiences of sexual assault or repeated, threatening sexual harassment that a Veteran experienced during his or her ... sexual nature, battery of a sexual nature, or sexual harassment which occurred while the Veteran was serving on ...

135

Applying the species concept to plant viruses.  

PubMed

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. The rationale for applying the species concept in virology is that viruses are biological entities and not chemicals: they possess genes, replicate, specialize, evolve and occupy specific ecological niches. The following definition is proposed: a virus species is a polythetic class of viruses constituting a replicating lineage and occupying a particular ecological niche. Such a definition of the species category does not and cannot provide a list of diagnostic properties for recognizing members of a particular virus species. It should also be stressed that a single property such as an arbitrary level of genome homology or the extent of serological relationship always fails to establish membership in a polythetic class. A binomial system of nomenclature is advocated in which the vernacular English name of the plant virus is adopted as the species name and the group name is assimilated to the level of genus. Adoption of this system would ensure that a universal classification system based on the classical categories of species, genus, and family becomes possible for all viruses. PMID:2647059

Van Regenmortel, M H

1989-01-01

136

A physical activity questionnaire: Reproducibility and validity  

Microsoft Academic Search

This study evaluates the Quantification de L'Activite Physique en Altitude chez les Enfants (QAPACE) supervised self- administered questionnaire reproducibility and validity on the estimation of the mean daily energy expenditure (DEE) on Bogotá's schoolchildren. The comprehension was assessed on 324 students, whereas the reproducibility was studied on a dif- ferent random sample of 162 who were exposed twice to it.

Nicolas Barbosa; Carlos E. Sanchez; Jose A. Vera; Wilson Perez; Jean-Christophe Thalabard; Michel Rieu

2007-01-01

137

Synchronous Objects for One Flat Thing, reproduced  

Microsoft Academic Search

Synchronous Objects for One Flat Thing, reproduced is an interactive screen-based work developed by The Ohio State University's Advanced Computing Center for the Arts and Design and the Department of Dance in collaboration with renowned choreographer William Forsythe. Pivoting on Forsythe's masterwork of visual complexity, One Flat Thing, reproduced (OFTr), the Synchronous Objects project seeks to enrich cross-disciplinary investigation and

Maria Palazzi; Norah Zuniga Shaw; William Forsythe; Matthew Lewis; Beth Albright; Michael Andereck; Sucheta Bhatawadekar; Hyowon Ban; Andrew Calhoun; Jane Drozd; Joshua Fry; Melissa Quintanilha; Anna Reed; Benjamin Schroeder; Lily Skove; Ashley Thorndike; Mary Twohig; Ola Ahlqvist; Peter Chan; Noel Cressie; Stephen Turk; Jill Johnson; Christopher Roman; Elizabeth Waterhouse; Scott deLahunta; Patrick Haggard; Alva Noe

2009-01-01

138

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

139

Sexual prejudice.  

PubMed

Despite shifts toward greater acceptance in U.S. public opinion and policy, lesbian, gay, and bisexual people remain widely stigmatized. This article reviews empirical research on sexual prejudice, that is, heterosexuals' internalization of cultural stigma, manifested in the form of negative attitudes toward sexual minorities and same-sex desires and behaviors. After briefly reviewing measurement issues, we discuss linkages between sexual prejudice and religion, gender, sexuality, and related variables, and consider how the cultural institutions encompassing these domains create a social context within which individual expressions of prejudice can meet important psychological needs. These include needs for securing social acceptance, affirming values that are central to one's self-concept, and avoiding anxiety and other negative emotions associated with threats to self-esteem. We conclude by discussing factors that may motivate heterosexuals to reduce their own sexual prejudice, including intergroup contact, as well as avenues for future empirical inquiry. PMID:22994920

Herek, Gregory M; McLemore, Kevin A

2012-09-17

140

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 contrast 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

141

[Sexual perversions or sexual variations?].  

PubMed

Beyond the usual perversions Freud described and psychiatric nosography, some new sexual behaviours are nowadays coming to light, with a view to overstepping limits, and this in a mood for provoking, if not transgressing! As with classic perversions, the very play, the ambiguity with sexual difference, seems to be the very game and not the classic denial of this difference. PMID:15123102

Lachcar, P

2004-04-01

142

Introduction to Wavelet Reproducing Kernel Particle Methods.  

National Technical Information Service (NTIS)

As summarized, several different meshless methods have been proposed, including smooth particle hydrodynamics, diffuse elements, element free Galerkin (EFG), particle in cell methods (PIC), wavelets, reproducing kernel particle methods (RKPM) and wavelet ...

W. K. Liu

1995-01-01

143

Tales of two snails: sexual selection and sexual conflict in Lymnaea stagnalis and Helix aspersa  

Microsoft Academic Search

Synopsis Sexual selection and sexual conflict have been shown to play key roles in the evolution of species with separate sexes. Experimental evidence is accumulating that this is also true for simultaneous hermaphrodites. For example, many species of land snails forcefully stab their mating partners with love darts. In the brown garden snail (Helix aspersa, now called Cantareus asperses), this

Joris M. Koene

2006-01-01

144

Synchronous objects for one flat thing, reproduced  

Microsoft Academic Search

Synchronous Objects for One Flat Thing, reproduced (http:\\/\\/synchronousobjects.osu.edu) is an interactive screen-based work developed by The Ohio State University's Advanced Computing Center for the Arts and Design (ACCAD) and the Department of Dance in collaboration with renowned choreographer William Forsythe. Pivoting on Forsythe's masterwork of visual complexity, One Flat Thing, Reproduced, as its research resource, the Synchronous Objects project seeks

Maria Palazzi; Norah Zuniga Shaw

2009-01-01

145

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

2011-10-28

146

Sexual Dysfunction  

Microsoft Academic Search

Homework assignments continue to be the most effective way of optimizing therapeutic gains in the treatment of sexual dysfunctions.\\u000a Some of the treatments for sexual dysfunctions, including the use of homework, have been scientifically supported. Other treatments\\u000a have been used with varying degrees of reported efficacy but have not been empirically validated. Nonetheless, sex therapy\\u000a homework typically involves a combination

Nancy Gambescia

147

Sex and the singular DM domain: insights into sexual regulation, evolution and plasticity  

Microsoft Academic Search

Most animals reproduce sexually, but the genetic and molecular mechanisms that determine the eventual sex of each embryo vary remarkably. DM domain genes, which are related to the insect gene doublesex, are integral to sexual development and its evolution in many metazoans. Recent studies of DM domain genes reveal mechanisms by which new sexual dimorphisms have evolved in invertebrates and

Clinton K. Matson; David Zarkower

2012-01-01

148

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 ...

149

Menopause and Sexuality  

MedlinePLUS

... Home > Menopause > Menopause and sexuality Menopause Menopause and sexuality Did you know? If you still get your ... with your partner More information on menopause and sexuality Sexual issues and menopause In the years around ...

150

Dealing with Sexual Problems  

MedlinePLUS

... Physical Side Effects » Sexual Side Effects in Women » Sexuality for the Woman with Cancer » Dealing with sexual ... saved articles window. My Saved Articles » My ACS » Sexuality for the Woman With Cancer + - Text Size Download ...

151

Child Sexual Abuse  

MedlinePLUS

... ABOUT US PTSD Awareness Month Child Sexual Abuse Child Sexual Abuse Share this page Search PTSD Site Choose Section Enter Term and Search Advanced Search What is child sexual abuse? Child sexual abuse includes a wide range of ...

152

Genetic control and evolution of sexually dimorphic characters in Drosophila  

Microsoft Academic Search

Sexually dimorphic abdominal pigmentation and segment morphology evolved recently in the melanogaster species group of the fruitfly Drosophila . Here we show that these traits are controlled by the bric-a-brac (bab) gene, which integrates regulatory inputs from the homeotic and sex-determination pathways. bab expression is modulated segment- and sex-specifically in sexually dimorphic species, but is uniform in sexually monomorphic species.

Artyom Kopp; Ian Duncan; Sean B. Carroll

2000-01-01

153

Reproducible measurements of MPI performance characteristics.  

SciTech Connect

In this paper we describe the difficulties inherent in making accurate, reproducible measurements of message-passing performance. We describe some of the mistakes often made in attempting such measurements and the consequences of such mistakes. We describe mpptest, a suite of performance measurement programs developed at Argonne National Laboratory, that attempts to avoid such mistakes and obtain reproducible measures of MPI performance that can be useful to both MPI implementers and MPI application writers. We include a number of illustrative examples of its use.

Gropp, W.; Lusk, E.

1999-06-25

154

Sexual Education and Morality.  

ERIC Educational Resources Information Center

Distinguishes five interpretations of sexual education including factual knowledge; self-control; stressing love; sexual training; and sexual morality. Suggests that sexual education should be understood as teaching children the moral tendencies relevant to sexual conduct. Argues that infantile sexual desire is based on a contradiction in terms…

Spiecker, Ben

1992-01-01

155

Adolescent Sexual Activity  

Microsoft Academic Search

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,

Paula K. Braverman; Victor C. Strasburger

1993-01-01

156

Tracing the evolution of brain and behavior using two related species of whiptail lizards: Cnemidophorus uniparens and Cnemidophorus inornatus.  

PubMed

Cnemidophorus whiptail lizards offer a unique opportunity to study behavioral and neural evolution because unlike most genera, ancestral and descendant species are still extant, and comparisons between species provide a window into correlated changes in biological organization through speciation. This review focuses on the all-female or parthenogenetic species Cnemidophorus uniparens (descendant species), which evolved through several hybridization events involving the sexually reproducing species Cnemidophorus inornatus (ancestral species). Data compiled over more than 2 decades include behavioral, endocrine, and neural differences between these two related species of whiptail lizards. For example, unlike females of the ancestral species, individuals of the descendant species display male-like mounting behavior (pseudocopulatory behavior) after ovulation. Pseudocopulatory behavior in the parthenogen is triggered by the progesterone surge after ovulation, and the behavioral capacity to respond to progesterone appears to be an ancestral trait that was inherited from C. inornatus males through the hybridization events. Interestingly, the regulation of sex steroid hormone receptor mRNA in brain areas critical for the expression of sociosexual behaviors differs between females of the two species and suggests that evolutionary changes in the regulation of gene expression could be a proximate mechanism that underlies the evolution of a novel social behavior in the parthenogen. Finally, because the sexual species is diploid, whereas the parthenogen is triploid, differences between the species could directly assess the effect of ploidy. The behavioral and neuroendocrinological data are pertinent for considering this possibility. PMID:14752207

Woolley, S C; Sakata, J T; Crews, D

2004-01-01

157

Effects of genotoxicity and its consequences at the population level in sexual and asexual Artemia assessed by analysis of inter-simple sequence repeats (ISSR).  

PubMed

There is considerable evidence that genetic damage in organisms occurs in the environment as a result of exposure to genotoxins and ionising radiation, but we have limited understanding of the extent to which this results in adverse consequences at a population level. We used inter-simple sequence repeat (ISSR) markers to quantify genotoxic effects of the mutagen ethylmethane sulfonate (EMS) on a sexual (Artemia franciscana) and an asexual (Artemia parthenogenetica) species of brine shrimp. The method provides information similar to that obtained with assessment of RAPD (random amplification of polymorphic DNA) but is more robust. Genetic damage was transmitted to the F1 generation in both Artemia species, but the sexual species showed a greater degree of recovery, as shown by higher values of genomic template stability. There was a strong correlation between DNA damage and effects on individual fitness parameters: size, survival, reproduction and population growth. These effects persisted into the F2 generation in A. parthenogenetica, but in the sexual A. franciscana only effects on fecundity continued beyond the exposed generation, even though there were substantial alterations in ISSR patterns in the F1 generation. Genetic biomarkers can thus be indicative of effects at the population level, but sexually reproducing species have a considerable assimilative capacity for the effects of genotoxins. PMID:23872504

Sukumaran, Sandhya; Grant, Alastair

2013-07-16

158

Males' evolutionary responses to experimental removal of sexual selection  

Microsoft Academic Search

We evaluated the in£uence of pre- and post-copulatory sexual selection upon male reproductive traits in a naturally promiscuous species, Drosophila melanogaster. Sexual selection was removed in two replicate populations through enforced monogamous mating with random mate assignment or retained in polyandrous controls. Monogamous mating eliminates all opportunities for mate competition, mate discrimination, sperm competition, cryptic female choice and, hence, sexual

Scott Pitnick; Gary T. Miller; Jennifer Reagan; Brett Holland

2001-01-01

159

Scientific Understanding of Sexual Orientation: Implications for Science Education.  

ERIC Educational Resources Information Center

|Discusses sexual orientation using the analogy of handedness. Points out the presence of diverse sexual behavior and homosexuality among living species and focuses on human behavior. Encourages discussions among biology teachers on the origins of sexual orientation. (Contains 27 references.) (YDS)|

Good, Ron; Hafner, Mark; Peebles, Patsye

2000-01-01

160

[Sexual dimorphism of marbled polecat Vormela peregusna (Carnivora: Mustelidae)].  

PubMed

Analysis of morphometric variation in 26 cranial characters were studied in 85 individuals of marbled polecat Vormela peregusna from Turkmenistan demonstrated a low level of sexual dimorphism in the species. The properties of sexual dimorphism in marbled polecat are discussed in terms of available hypotheses of sexual dimorphism in carnivores. PMID:16634435

Rozhnov, V V; Abramov, A V

161

Sexual selection resulting from extrapair paternity in collared flycatchers  

Microsoft Academic Search

Extrapair paternity has been suggested to represent a potentially important source of sexual selection on male secondary sexual characters, particularly in birds with predominantly socially monogamous mating systems. However, relatively few studies have demonstrated sexual selection within single species by this mechanism, and there have been few attempts to assess the importance of extrapair paternity in relation to other mechanisms

BEN C. SHELDON; HANS ELLEGREN

1999-01-01

162

Female remating, sperm competition and sexual selection in Drosophila Review  

Microsoft Academic Search

Female remating is fundamental to evolutionary biology as it determines the pattern of sexual selection and sexual conflict. Remating in females is an important component of Drosophila mating systems because it affects sperm usage patterns and sexual selection. Remating is common in females of many species of Drosophila in both natural and laboratory populations. It has been reported in many

Shree Ram Singh; Bashisth N. Singh; Hugo F. Hoenigsberg

163

Sexual Rehabilitation  

PubMed Central

Sexual rehabilitation begins with an awareness of the potential for sex difficulties following any disruption in health. A thorough sex-functioning history and an exploration of the patient's (and partner's) expectations, limitations and potentials will enable the professional to understand the reasons why sex activity has not resumed after illness, accident or surgery and to offer appropriate therapy. Acceptance, validation, appropriate reassurance, accurate information and specific suggestion: these forms of “sex therapy” fall within the capabilities of every family physician. When applied early in the course of an illness, such interventions will initiate the process of sexual rehabilitation and may well prevent more severe dysfunction.

Stevenson, R.W.D.

1986-01-01

164

The Reproducibility of Sputum Gram Film Interpretation  

Microsoft Academic Search

Objectives: To evaluate the reproducibility with which microbiologists interpret Gram-stained sputa and examine the effect of the smear preparation method.Methods: Two hundred and ten coded slides prepared directly from a purulent portion of sputum (DS) and 140 slides prepared after homogenization of the same sputum (HS) were examined by three experienced microbiologists. Aproportion of the slides prepared by each method

G. W Smith; R. R White; E. R Ridgeway; J. E Corkill

2000-01-01

165

Data reproducibility in fluorescence image analysis  

Microsoft Academic Search

Fluorescence image analysis provides quantitative data on fluorescence in situ hybridiza-tion signals (FISH), immunofluorescence labelings, Green Fluorescent Protein (GFP) expression and microarrays. It is a valuable tool for decision making in the fields of biology and medicine. The aim of this study was to evaluate the reproducibility of fluorescence intensity measurements and standardization when acquisitions are performed under various but

Catherine Souchier; Christine Brisson; Bernadette Batteux; Michel Robert-Nicoud; Paul-André Bryon

2004-01-01

166

Explicit recursivity into reproducing kernel Hilbert spaces  

Microsoft Academic Search

Thispaper presentsa methodologyto developrecursivefilters in reproducing kernel Hilbert spaces (RKHS). Unlike previous approaches that exploit the kernel trick on filtered and then mapped samples, we explicitly define model recursivity in the Hilbert space. The method exploits some properties of functionalanalysis and recursive computation of dot products without the need of pre-imaging. We illustrate the feasibility of the methodology in the

Devis Tuia; Gustavo Camps-Valls; Manel Martinez-Ramon

2011-01-01

167

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…

Lobb, Nancy

168

Reproducing Groups for the Metaplectic Representation  

Microsoft Academic Search

We consider the (extended) metaplectic representation of the semidirect product G of the symplectic group and the Heisenberg group. By looking at the standard resolution of the identity formula and inspired by previous work [5], [13], [4], we introduce the notion of admissible (reproducing) subgroup of G via the Wigner distribution. We prove some features of admissible groups and then

E. Cordero; F. DE MARI; K. Nowak; A. Tabacco

169

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.

170

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

171

Reproducing color images using custom inks  

Microsoft Academic Search

We investigate the general problem of reproducing color images on an offset press using custom inks in any combination and number. While this problem has been explored previously for the case of two inks, there are a number of new mathematical and algorithmic chal- lenges that arise as the number of inks increases. These challenges include more complex gamut mapping

Eric J. Stollnitz; Victor Ostromoukhov; David H. Salesin

1998-01-01

172

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

173

Testosterone Stimulates Mounting Behavior and Arginine Vasotocin Expression in the Brain of both Sexual and Unisexual Whiptail Lizards  

PubMed Central

In nonmammalian vertebrates the abundance of arginine vasotocin (AVT) neurons in the brain is sexually dimorphic, a pattern that is modulated by testicular androgen. This peptide is thought to be involved in the control of male-typical mounting behaviors. The all-female desert-grasslands whiptail (Cnemidophorus uniparens) reproduces by obligate parthenogenesis and in nature no males exist, but eggs treated with aromatase inhibitor hatch into individuals (called virago C. uniparens) having testes, accessory sex structures, high circulating concentrations of androgens, and exhibiting only male-like copulatory behavior. To examine the ‘sexual’ dimorphism of AVT-containing neurons in these animals, we compared AVT immunoreactivity in gonadectomized control and virago C. uniparens, with that of gonadectomized male and female Cnemidophorus inornatus, a sexual species that is the maternal ancestor to the parthenogenetic species. Mounting behavior is elicited in both species and both sexes by testosterone, and it was predicted that the distribution and abundance of AVT cell bodies and fibers would reflect the propensity of males and females of the two species to display male-typical copulatory behavior. Since both this propensity and AVT abundance are controlled by androgens, we compared testosterone-implanted and control animals within each group. Testosterone treatment generally increased AVT abundance, except in lab-reared parthenoforms, in which testosterone treatment was the least effective in inducing male-like copulatory behavior.

Hillsman, K.D.; Sanderson, N.S.; Crews, D.

2008-01-01

174

Testosterone stimulates mounting behavior and arginine vasotocin expression in the brain of both sexual and unisexual whiptail lizards.  

PubMed

In nonmammalian vertebrates the abundance of arginine vasotocin (AVT) neurons in the brain is sexually dimorphic, a pattern that is modulated by testicular androgen. This peptide is thought to be involved in the control of male-typical mounting behaviors. The all-female desert-grasslands whiptail (Cnemidophorus uniparens) reproduces by obligate parthenogenesis and in nature no males exist, but eggs treated with aromatase inhibitor hatch into individuals (called virago C. uniparens) having testes, accessory sex structures, high circulating concentrations of androgens, and exhibiting only male-like copulatory behavior. To examine the 'sexual' dimorphism of AVT-containing neurons in these animals, we compared AVT immunoreactivity in gonadectomized control and virago C. uniparens, with that of gonadectomized male and female Cnemidophorus inornatus, a sexual species that is the maternal ancestor to the parthenogenetic species. Mounting behavior is elicited in both species and both sexes by testosterone, and it was predicted that the distribution and abundance of AVT cell bodies and fibers would reflect the propensity of males and females of the two species to display male-typical copulatory behavior. Since both this propensity and AVT abundance are controlled by androgens, we compared testosterone-implanted and control animals within each group. Testosterone treatment generally increased AVT abundance, except in lab-reared parthenoforms, in which testosterone treatment was the least effective in inducing male-like copulatory behavior. PMID:18391518

Hillsman, K D; Sanderson, N S; Crews, D

2007-01-01

175

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

176

Evolutionary rates of secondary sexual and non-sexual characters among birds  

Microsoft Academic Search

The rate of evolutionary morphological change in secondary sexual characters among species has traditionally been assumed\\u000a to exceed that for non-sexual characters, giving rise to a larger degree of divergence. We used a large data set of independent\\u000a evolutionary events of exaggerated secondary sexual feather characters across all birds to test whether that was the case.\\u000a Comparative analyses revealed that

José Javier Cuervo; Anders Pape Møller

1999-01-01

177

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.

Monnet, Jean-Matthieu; Cherry, Michael I

2002-01-01

178

Reproducibility of technetium-99m ethylenedicysteine clearance  

Microsoft Academic Search

.   It has been shown that technetium-99m ethylenedicysteine (99mTc-EC) clearance displays a strong correlation with orthoiodohippurate clearance and that it is possible to estimate effective\\u000a renal plasma flow from 99mTc-EC clearance. However, in routine practice, when monitoring renal function of patients by clearance determinations it is\\u000a imperative to test the reproducibility of the clearance technique in order to decide whether

Levent Kabasakal; Metin Halaç; Ebru Alkan; Nihat Özçelik; I. lhami Uslu

1999-01-01

179

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

180

Sexual Selection and Larval Performance of Two Species of Red-Eyed Treefrogs, Agalychnis callidryas and A. moreletii of the Chiquibul Forest Reserve, Belize  

Microsoft Academic Search

In species where males do not provide immediate benefits to females in the form of resources or parental care to offspring, adaptive mate choice may be maintained by selection because preferred males sire offspring that are genetically superior. I test the hypothesis that female mating preferences result in enhanced performance of their larvae, owing to genetic variation among sires in

Venetia Samantha Briggs

2007-01-01

181

Reproducibility of serum cytokines and growth factors  

PubMed Central

Background In most studies, circulating biomarkers are usually assessed from a single sample, assuming that this single measurement represents the long-term biomarker status of the individual. Such an assumption is rarely tested although it may not be valid for all biomarkers. The objective of this study was to investigate the temporal reproducibility of a panel of cytokines and growth factors. Methods Thirty-five postmenopausal women with two annual visits and 30 premenopausal women with three annual visits were randomly selected from the participants in an existing prospective cohort. A total of 23 serum cytokines, nine growth factors and C-reactive protein (CRP) were measured using the Luminex xMap™ technology. In addition, for eight biomarkers, regular and high sensitivity (hs) assays were compared. Results The biomarkers with adequate (>60%) detection rates and acceptable (?0.55) intra-class correlation coefficients (ICCs) were: hsIL-1?, IL-1RA, hsIL-2, hsIL-4, hsIL-5, hsIL-6, hsIL-10, IL-12p40, hsIL-12p70, hsTNF-?, TNF-R1, TNF-R2, CRP, HGF, NGF, and EGFR. The remaining biomarkers either had low temporal reproducibility or were undetectable in more than 40% of samples. Conclusions The results suggest that 16 of the 41 biomarkers measured with Luminex technology showed sufficient sensitivity and temporal reproducibility in sera.

Gu, Yian; Zeleniuch-Jacquotte, Anne; Linkov, Faina; Koenig, Karen L.; Liu, Mengling; Velikokhatnaya, Lyudmila; Shore, Roy E.; Marrangoni, Adele; Toniolo, Paolo; Lokshin, Anna E.; Arslan, Alan A.

2010-01-01

182

Optimization of reproduced Morpho-blue coloration  

NASA Astrophysics Data System (ADS)

Morpho butterfly's metallic blue luster, which is produced from the butterfly's scale, has a mysterious feature. Since the scale does not contain a blue pigment, the origin of the coloration is attributed to a microscopic structure that can also explain its high reflectivity. However, it appears blue from wide angular range, which contradicts obviously the grating or multilayer. The mystery of the lack of multi-coloration has recently been explained with a peculiar nano-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, optical properties of the fabricated film were found to contain still some differences with that of the Morpho-butterfly, although the basic characteristics of the Morpho-blue itself was reproduced. In order to make the artificial Morpho-blue closer to the natural one than the prototype, we attempted to optimize the artificial film structure by controlling fabrication parameters. In this process, optical simulations and micro-structural observations were taken in account. By comparing a series of films fabricated with different nano-patterns, optimized parameters were semi-empirically obtained. Also the relationship between the structural parameters and the optical properties was analyzed. The reflective characteristics of the optimized film were found to reproduce the optical properties more closely to the natural Morpho-blue than the prototypes.

Saito, Akira; Ishikawa, Yoko; Miyamura, Yusuke; Akai-Kasaya, Megumi; Kuwahara, Yuji

2007-10-01

183

Evolutionary and ecological implications of sexual parasitism.  

PubMed

Sexual parasites offer unique insights into asexual and sexual reproduction. They mate with a 'host' whose genetic contribution is discarded either immediately (in androgenesis or gynogenesis) or after a delay of one generation (in hybridogenesis). The discarded genome can be maternal or paternal, implying that not only females but also males can reproduce asexually. The resulting lineages are often older than ecological or evolutionary theory predicts. Sexual parasites have links to a diverse set of concepts: selfish genetic elements, degradation of clonal genomes, evolution of sex, mate-choice theory, and host-parasite dynamics. We discuss the different sexually parasitic systems in both hermaphrodites and gonochoristic organisms, emphasizing their similarities and differences in ecological and evolutionary settings. PMID:23399316

Lehtonen, Jussi; Schmidt, Daniel J; Heubel, Katja; Kokko, Hanna

2013-02-08

184

Senescing sexual ornaments recover after a sabbatical.  

PubMed

Somatic deterioration in ageing animals may arise from allocation of resources to reproduction at the expense of repair and maintenance. Thus, accumulated reproductive effort is likely to progressively limit the expression of sexual ornaments at older ages. We analysed the effect of age and reproductive effort on the sexual attractiveness (foot colour) of male blue-footed boobies. Using a long-term dataset, we found that, as animals age and accumulate reproductive events, the expression of foot colour deteriorates. In addition, after non-breeding events males displayed more colourful feet compared with males that reproduced the year before, suggesting that sabbatical years facilitate recovery. Our results indirectly support the idea that allocation of resources to reproduction limits sexual attractiveness and that animals could cope with the negative effects of senescence on sexual ornaments by skipping some breeding events. PMID:19955170

Velando, Alberto; Drummond, Hugh; Torres, Roxana

2009-12-02

185

Sexual experience of male rats influences anxiety-like behavior and androgen levels  

Microsoft Academic Search

There is a wide body of literature to suggest that sexual experience may influence androgen secretion in various species, in turn, androgens may also influence anxiety. We hypothesized that sexual experience may alter anxiety behavior and secretion of endogenous androgens. Experiment 1: anxiety behavior of rats with a history of sexual experience was compared to that of sexually-inexperienced, naïve male

Kassandra L. Edinger; Cheryl A. Frye

2007-01-01

186

Inter- and intra-specific cuticle variation between amphimictic and parthenogenetic species of root-knot nematode (Meloidogyne spp.) as revealed by a bacterial parasite (Pasteuria penetrans).  

PubMed

Specific host-parasite interactions exist between species and strains of plant parasitic root-knot nematodes and the Gram-positive bacterial hyperparasite Pasteuria penetrans. This bacterium produces endospores that adhere to the cuticle of migrating juveniles, germinate and colonise the developing female within roots. Endospore attachment of P. penetrans populations to second-stage juveniles of the root-knot nematode species Meloidogyne incognita and Meloidogyne hapla showed there were interactive differences between bacterial populations and nematode species. Infected females of M. incognita produced a few progeny which were used to establish two nematode lines from single infective juveniles encumbered with either three or 26 endospores. Single juvenile descent lines of each nematode species were produced to test whether cuticle variation was greater within M. hapla lines that reproduce by facultative meiotic parthenogenesis than within lines of M. incognita, which reproduces by obligate parthenogenesis. Assays revealed variability between broods of individual females derived from single second-stage juvenile descent lines of both M. incognita and M. hapla suggesting that progeny derived from a single individual can differ in spore adhesion in both sexual and asexual nematode species. These results suggest that special mechanisms that produced these functional differences in the cuticle surface may have evolved in both sexually and asexually reproducing nematodes as a strategy to circumvent infection by this specialised hyperparasite. PMID:18171577

Davies, K G; Rowe, J A; Williamson, V M

2007-12-03

187

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

188

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

189

Sexuality after breast cancer  

Microsoft Academic Search

Breast cancer (BC) may affect three main domains of women's sexuality: sexual identity, sexual function and sexual relationship. Age, lymphedema, side-effects of surgery, radio-, chemo- and hormonotherapy, pregnancy-related problems, infertility, iatrogenic premature menopause, with its cohort of symptoms secondary to the chronic loss of estrogens on the brain, on the sensory organs, on the pathophysiology of sexual response and on

A. Graziottin; V. Rovei

2007-01-01

190

Variation in allocation to sexual and asexual reproduction among clones of cyclically parthenogenetic Daphnia pulex (Crustacea: Cladocera)  

Microsoft Academic Search

Organisms reproducing by cyclical parthenogenesis combine the benefits of both sexual and asexual reproduction within the same life cycle. Few studies have examined the evolution of variation in the pattern of investment in parthenogenetic compared to sexual reproduction. Seven clones of Daphnia pulex (Crustacea: Cladocera) varying in allocation to sexual reproduction, as measured by the production of males, were raised

D. J. INNES; D. R. SINGLETON

2000-01-01

191

Variation in allocation to sexual and asexual reproduction among clones of cyclically parthenogenetic Daphnia pulex (Crustacea: Gladocera)  

Microsoft Academic Search

Organisms reproducing by cyclical parthenogenesis combine the benefits of both sexual and asexual reproduction within the same life cycle. Few studies have examined the evolution of variation in the pattern of investment in parthenogenetic compared to sexual reproduction. Seven clones of Daphnia pulex (Crustacea: Cladocera) varying in allocation to sexual re- production, as measured by the production of males, were

D. J. INNES; D. R. SINGLETON

2000-01-01

192

The GermOnline cross-species systems browser provides comprehensive information on genes and gene products relevant for sexual reproduction  

Microsoft Academic Search

We report a novel release of the GermOnline know- ledgebase covering genes relevant for the cell cycle, gametogenesis and fertility. GermOnline was ex- tended into a cross-species systems browser includ- ing information on DNA sequence annotation, gene expression and the function of gene products. The database covers eight model organisms and Homo sapiens, for which complete genome annotation data are

Alexandre Gattiker; Christa Niederhauser-wiederkehr; James Moore; Leandro Hermida; Michael Primig

2007-01-01

193

Sexual conflict, sexual selection and sperm competition in the spawning decisions of bitterling, Rhodeus sericeus  

Microsoft Academic Search

Sexual selection may operate through either direct selection on preference genes or indirect genetic benefits. However, in many species both direct and indirect selection may operate and can influence female mate and oviposition choice. Adaptations by males for sperm competition can also affect female mate and oviposition choice and can lead to sexual conflict. We investigated the role of direct

Carl Smith; Alex Douglas; Pavel Jurajda

2002-01-01

194

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

PubMed Central

Background It is widely agreed that species are fundamental units of biology, but there is little agreement on a definition of species or on an operational criterion for delimiting species that is applicable to all organisms. Methodology/Principal Findings We focus on asexual eukaryotes as the simplest case for investigating species and speciation. We describe a model of speciation in asexual organisms based on basic principles of population and evolutionary genetics. The resulting species are independently evolving populations as described by the evolutionary species concept or the general lineage species concept. Based on this model, we describe a procedure for using gene sequences from small samples of individuals to assign them to the same or different species. Using this method of species delimitation, we demonstrate the existence of species as independent evolutionary units in seven groups of invertebrates, fungi, and protists that reproduce asexually most or all of the time. Conclusions/Significance This wide evolutionary sampling establishes the general existence of species and speciation in asexual organisms. The method is well suited for measuring species diversity when phenotypic data are insufficient to distinguish species, or are not available, as in DNA barcoding and environmental sequencing. We argue that it is also widely applicable to sexual organisms.

Birky, C. William; Adams, Joshua; Gemmel, Marlea; Perry, Julia

2010-01-01

195

Male sexual harassment alters female social behaviour towards other females.  

PubMed

Male harassment of females to gain mating opportunities is a consequence of an evolutionary conflict of interest between the sexes over reproduction and is common among sexually reproducing species. Male Trinidadian guppies Poecilia reticulata spend a large proportion of their time harassing females for copulations and their presence in female social groups has been shown to disrupt female-female social networks and the propensity for females to develop social recognition based on familiarity. In this study, we investigate the behavioural mechanisms that may lead to this disruption of female sociality. Using two experiments, we test the hypothesis that male presence will directly affect social behaviours expressed by females towards other females in the population. In experiment one, we tested for an effect of male presence on female shoaling behaviour and found that, in the presence of a free-swimming male guppy, females spent shorter amounts of time with other females than when in the presence of a free-swimming female guppy. In experiment two, we tested for an effect of male presence on the incidence of aggressive behaviour among female guppies. When males were present in a shoal, females exhibited increased levels of overall aggression towards other females compared with female only shoals. Our work provides direct evidence that the presence of sexually harassing males alters female-female social behaviour, an effect that we expect will be recurrent across taxonomic groups. PMID:21976624

Darden, Safi K; Watts, Lauren

2011-10-05

196

Male sexual harassment alters female social behaviour towards other females  

PubMed Central

Male harassment of females to gain mating opportunities is a consequence of an evolutionary conflict of interest between the sexes over reproduction and is common among sexually reproducing species. Male Trinidadian guppies Poecilia reticulata spend a large proportion of their time harassing females for copulations and their presence in female social groups has been shown to disrupt female–female social networks and the propensity for females to develop social recognition based on familiarity. In this study, we investigate the behavioural mechanisms that may lead to this disruption of female sociality. Using two experiments, we test the hypothesis that male presence will directly affect social behaviours expressed by females towards other females in the population. In experiment one, we tested for an effect of male presence on female shoaling behaviour and found that, in the presence of a free-swimming male guppy, females spent shorter amounts of time with other females than when in the presence of a free-swimming female guppy. In experiment two, we tested for an effect of male presence on the incidence of aggressive behaviour among female guppies. When males were present in a shoal, females exhibited increased levels of overall aggression towards other females compared with female only shoals. Our work provides direct evidence that the presence of sexually harassing males alters female–female social behaviour, an effect that we expect will be recurrent across taxonomic groups.

Darden, Safi K.; Watts, Lauren

2012-01-01

197

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

198

Sexual function, sexual abuse and sexually transmitted diseases in adolescence  

Microsoft Academic Search

As adolescents progress through puberty, many biological changes occur and, for young women, this includes the onset of menses and the capability for reproduction. During this time, sexual identity is developed and expressions of sexuality become more frequent. Adolescent women engage in a variety of sexual behaviours, both non-coital and coital. As teens begin dating relationships, they are at risk

Margaret J. Blythe

2003-01-01

199

"Sexual" behavior in parthenogenetic lizards (Cnemidophorus)  

PubMed Central

All-female, parthenogenetic species afford a unique test of hypotheses regarding the nature and evolution of sexuality. Basic data on the behavior of parthenogens are lacking, however. We have discovered, from observations of captive Cnemidophorus uniparens, C. velox, and C. tesselatus, behavior patterns remarkably similar to the courtship and copulatory behavior of closely related sexual species. Briefly, in separately housed pairs, one lizard was repeatedly seen to mount and ride its cagemate and appose the cloacal regions. Dissection or palpation revealed that, in each instance, the courted animal was reproductively active, having ovaries containing large, preovulatory follicles, while the courting animal was either reproductively inactive or postovulatory, having ovaries containing only small, undeveloped follicles. These observations are significant for the questions they raise. For example, is this behavior a nonfunctional vestige of the species' ancestry, or is this behavior necessary for successful reproduction in the species (e.g., by priming reproductive neuroendocrine mechanisms as has been demonstrated in sexual species)? Images

Crews, David; Fitzgerald, Kevin T.

1980-01-01

200

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 ...

201

Sexually Transmitted Diseases  

MedlinePLUS

... of this website will be limited. Search Help? Sexually Transmitted Diseases Share this page: Was this page helpful? Overview | Related Pages Also known as: STDs; Sexually transmitted infections; STIs; Venereal diseases What are sexually transmitted diseases? ...

202

Sexual Dysfunction in Women  

MedlinePLUS

... also cause sexual dysfunction. You may have less sexual desire during pregnancy, right after childbirth or when you are breastfeeding. After menopause many women feel less sexual desire, have vaginal dryness or have pain during sex ...

203

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

204

Sexual swellings in wild white-handed gibbon females ( Hylobates lar) indicate the probability of ovulation  

Microsoft Academic Search

Conspicuous sexual swellings in the females of some primate species have been a focus of scientific interest since Darwin first wrote about them in 1871. To understand these visual signals, research focused on exaggerated sexual swellings of Old World primates. However, some primate species develop much smaller sexual swellings and it is as yet unclear if these smaller swellings can

Claudia Barelli; Michael Heistermann; Christophe Boesch; Ulrich H. Reichard

2007-01-01

205

The Role of Body Size in Mating Interactions of the Sexually Cannibalistic Fishing Spider Dolomedes triton  

Microsoft Academic Search

Some arachnids display extreme sexual size dimorphism (SSD) with adult females being several times larger than adult males. One explanation for SSD in species that exhibit pre-copulatory sexual cannibalism (female attack, kill and consumption of the male prior to mating) is that smaller males may be less likely victims of predatory attacks by females. However, in some sexually cannibalistic species

J. Chadwick Johnson

2005-01-01

206

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

207

Highly reproducible chronoamperometric analysis in microdroplets.  

PubMed

Here we report a method for highly reproducible chronoamperometric analysis of the contents of microdroplets. Aqueous microdroplets having volumes on the order of 1 nL and separated by a fluorocarbon solvent are generated within a microfluidic device using a T-shaped junction. The key finding is that stable and reproducible quasi-steady-state currents are observed if the electrochemical measurements are made in a narrowed segment of a microchannel. Under these conditions, the microdroplets are stretched, here by a factor of 10, leading to desirable intradroplet mass transfer characteristics. Microdroplet frequencies up to 0.67 s(-1) are accessible using this method. The quasi-steady-state currents resulting from chronoamperometric analysis of microdroplets containing 1.0 mM Ru(NH3)6(3+) have relative standard deviations of just 1.8% and 2.8% at flow rates of 30 nL min(-1) and 60 nL min(-1), respectively. Importantly, the design of the microelectrochemical device ensures direct contact between intradroplet redox molecules and the electrode surface. That is, the fluorocarbon between microdroplets does interfere with inner-sphere electrocatalytic processes such as the oxygen reduction reaction. Finite-element simulations are presented that are in accord with the experimental findings. PMID:23386119

Liu, Hong; Crooks, Richard M

2013-04-01

208

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, TiO2 and SiO2 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

2006-09-01

209

Inverted Orientalism and the discursive construction of sexual harassment: A study of mass media and feminist representations of sexual harassment in Japan  

Microsoft Academic Search

The purpose of this study is to address how the discourse on sexual harassment in Japan reproduces the taken-for-granted cultural framework. I propose looking at the recent emergence of sexual harassment talk in Japan as what I call an “Inverted Orientalist” process. To do so is to articulate how the Orientalist binary of native tradition and Western modernity is appropriated

Hiroko Hirakawa

1998-01-01

210

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

211

Proximate developmental mediators of sexual dimorphism in size: case studies from squamate reptiles  

Microsoft Academic Search

Synopsis Sexual dimorphism in size (sexual size dimorphism; SSD) is nearly ubiquitous, but the relative importance of genetic versus environmental control of SSD is not known for most species. We investigated proximate determinants of SSD in several species of squamate reptiles, including three species of Sceloporus lizards and the diamond-backed rattlesnake (Crotalus atrox). In natural populations of these species, SSD

Henry B. John-Alder; Robert M. Cox; Emily N. Taylor

2007-01-01

212

P-Value Precision and Reproducibility  

PubMed Central

Summary P-values are useful statistical measures of evidence against a null hypothesis. In contrast to other statistical estimates, however, their sample-to-sample variability is usually not considered or estimated, and therefore not fully appreciated. Via a systematic study of log-scale p-value standard errors, bootstrap prediction bounds, and reproducibility probabilities for future replicate p-values, we show that p-values exhibit surprisingly large variability in typical data situations. In addition to providing context to discussions about the failure of statistical results to replicate, our findings shed light on the relative value of exact p-values vis-a-vis approximate p-values, and indicate that the use of *, **, and *** to denote levels .05, .01, and .001 of statistical significance in subject-matter journals is about the right level of precision for reporting p-values when judged by widely accepted rules for rounding statistical estimates.

Boos, Dennis D.; Stefanski, Leonard A.

2011-01-01

213

The GermOnline cross-species systems browser provides comprehensive information on genes and gene products relevant for sexual reproduction  

PubMed Central

We report a novel release of the GermOnline knowledgebase covering genes relevant for the cell cycle, gametogenesis and fertility. GermOnline was extended into a cross-species systems browser including information on DNA sequence annotation, gene expression and the function of gene products. The database covers eight model organisms and Homo sapiens, for which complete genome annotation data are available. The database is now built around a sophisticated genome browser (Ensembl), our own microarray information management and annotation system (MIMAS) used to extensively describe experimental data obtained with high-density oligonucleotide microarrays (GeneChips) and a comprehensive system for online editing of database entries (MediaWiki). The RNA data include results from classical microarrays as well as tiling arrays that yield information on RNA expression levels, transcript start sites and lengths as well as exon composition. Members of the research community are solicited to help GermOnline curators keep database entries on genes and gene products complete and accurate. The database is accessible at .

Gattiker, Alexandre; Niederhauser-Wiederkehr, Christa; Moore, James; Hermida, Leandro; Primig, Michael

2007-01-01

214

Sexual cannibalism in scorpions: fact or fiction?  

Microsoft Academic Search

Females of several scorpion species are currently deemed to be sexual cannibals, but this reputation is, however, largely built on anecdotal evidence from the older literature. Theoretical models predict that given the low rates of female-male encounter, males should allow themselves to be cannibalized after sperm transfer. The present paper examines the information available for a number of species to

ALFREDO V PERETTI; LUIS E ACOSTA; TIM G BENTON

1999-01-01

215

Sexually Selected Infanticide in a Polygynous Bat  

Microsoft Academic Search

BackgroundAdult 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

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

2011-01-01

216

Sexual coercion and the misperception of sexual intent  

Microsoft Academic Search

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

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

2008-01-01

217

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.

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

2011-01-01

218

Adolescents’ sexual media diets  

Microsoft Academic Search

A model of how adolescents choose, interpret, and interact with the mass media is discussed in the context of sexual development. The Media Practice Model suggests that adolescents select and react to sexual media diets that speak to an emerging sense of themselves as sexual human beings. Relatively little is known about how the sexual content adolescents attend to in

Jane D Brown

2000-01-01

219

Alcohol and Sexual Assault  

Microsoft Academic Search

Conservative estimates of sexual assault prevalence suggest that 25 percent of American women have experienced sexual assault, including rape. Approximately one-half of those cases involve alcohol consumption by the perpetrator, victim, or both. Alcohol contributes to sexual assault through multiple pathways, often exacerbating existing risk factors. Beliefs about alcohol's effects on sexual and aggressive behavior, stereotypes about drinking women, and

Antonia Abbey; Tina Zawacki; Philip O. Buck; A. Monique Clinton; Pam McAuslan

2001-01-01

220

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…

Brooks, Nancy A.

1988-01-01

221

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

222

Sexual addiction and clergy  

Microsoft Academic Search

In this article the concept of sexual addiction is defined and briefly illustrated. It is argued that this is a viable concept for understanding the sexual misconduct, including abusive and exploitive activity, of some clergy. The author believes that sexual addiction becomes intertwined with the role of pastor to form the identity of the sexually addicted clergy. A typology of

Mark R. Laaser

1991-01-01

223

Toenail selenium as biomarker: reproducibility over a one-year period and factors influencing reproducibility.  

PubMed

We assessed the reproducibility of selenium levels in toenails, comparing concentrations in two sets of specimens collected about a year apart, from 80 women (40 pre-menopausal and 40 post-menopausal) in the period October 1990 to February 1992. The women were participants in a prospective study on hormones and diet in relation to prediagnostic breast cancer (the ORDET study) conducted in northern Italy. Toenail selenium was determined by electrothermal atomic absorption spectrometry. The data were log-transformed as they were not normally distributed. To assess reproducibility Pearson correlation coefficients (r) for the two selenium determinations were calculated in pre- and post-menopausal women, according to smoking status and acetone treatment. A weighted kappa statistic (k) assessed inter-quintile agreement between the two sets of measures. Toenail selenium levels were highly reproducible (r = 0.57, p < 0.001), especially in pre-menopausal women (r = 0.66, p <0.001). Smoking lowered selenium levels (mean difference of 0.24 microg/g, p < 0.05 between smokers and non smokers) but did not significantly influence reproducibility. Acetone treatment to remove nail polish did not modify selenium levels but affected inter-quintile agreement, with moderate agreement (k = 0.58, p < 0.001) when acetone was used at both or neither samplings; and fair non significant agreement (k = 0.39, p = 0.06) when acetone was used at one sampling but not the other. As selenium levels in toenails are highly reproducible, notwithstanding variation in selenium levels in food and long-term changes in individuals' food choices, toenail selenium may be a useful biomarker of selenium exposure, particularly since toenail samples provide a measure of long-term exposure. However age, smoking status and acetone treatment are possible causes of misclassification. PMID:14650626

Krogh, Vittorio; Pala, Valeria; Vinceti, Marco; Berrino, Franco; Ganzi, Angela; Micheli, Andrea; Muti, Paola; Vescovi, Luciano; Ferrari, Angela; Fortini, Katia; Sieri, Sabina; Vivoli, Gianfranco

2003-01-01

224

SEXUAL SIZE DIMORPHISM OF THE MUSK DUCK  

Microsoft Academic Search

We examined sexual size dimorphism of a lek-displaying diving duck from Australia, the Musk Duck (Biziura lobata). Like other lek-displaying species, Musk Ducks exhibit extreme sexual size di- morphism in addition to structural dimorphism. Body mass ratios (male:female) for Musk Ducks are among the highest reported for birds (more than 3:1). Multivariate analyses of 16 anatomical measurements indicated that body

Kevin G. McCracken; David C. Paton; Alan D. Afton

2000-01-01

225

Sexuality and Gynecological Care  

Microsoft Academic Search

\\u000a This chapter considers concepts of sexuality and gynecological care for children and adolescents with neurodevelopmental disabilities.\\u000a Issues reviewed include normal human sexuality, sexuality education, sexual abuse, contraception, gynecological care, and\\u000a sexual dysfunction. It is important for all children and youth including those with disabilities to have access to such important\\u000a education and health care. All humans deserve optimum quality of

Donald E. Greydanus; Hatim A. Omar

226

Women, Alcohol, and Sexuality  

Microsoft Academic Search

Alcohol consumption increases subjective sexual desire, arousal, and pleasure for many women, although it lowers physiological\\u000a arousal. Despite the general belief that alcohol disinhibits female sexual behaviors, alcohol leads to changes in sexual behavior\\u000a only for a minority of women. Expectancies about the effects of alcohol on sexual behavior may be important mediators of the\\u000a alcohol-sexual behavior linkage. There also

Linda J. Beckman; Kimberly T. Ackerman

227

Traceability, reproducibility, and comparability of grid calibrations  

NASA Astrophysics Data System (ADS)

The national metrology institute of Germany, PTB, offers traceable, two-dimensional pattern placement calibrations of microstructures on masks. Whereas the measurement uncertainty for the calibrated pattern positions in terms of traceable coordinate values is only comparable to the position tolerances actually required for mask patterning, i.e. about 35 nm, the deviations from the design grid can be determined with smaller uncertainties. In calibration certificates offered by PTB, these differences are taken into account and the uncertainties for the length of the grid and the uncertainties for the position deviations from the design grid are quoted separately as 30 nm and 10 nm respectively. Developments to further reduce the uncertainties are under way. An analysis of photomask recalibration results shows the long-term reproducibility of PTB length calibrations to be better than 15 nm or 1*10-7, including substrate stability effects. Details of the recalibration results will be given. Leica Microsystems Lithography runs a laboratory for two-dimensional pattern placement calibrations, formally accredited by PTB within DKD, the German calibration service. Results of recent comparison measurements between the DKD laboratory and PTB on masks of different size will be given and discussed as an example of the process of dissemination of the length unit to industry.

Bosse, Harald; Haessler-Grohne, Wolfgang; Brendel, Bernd

1999-12-01

228

Reproducing natural spider silks' copolymer behavior in synthetic silk mimics.  

PubMed

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

2012-11-08

229

Sexuality and Islam.  

PubMed

This paper deals with three major questions: (1) What are the sexual norms defined by the sacred texts (Koran and Sunna)? (2) What are the sexual practices currently observed among Moslems? (3) To which extent are current sexual practices of Moslems dissociated from Islamic sexual norms? Sexual standards in Islam are paradoxical: on the one hand, they allow and actually are an enticement to the exercise of sexuality but, on the other hand, they discriminate between male and female sexuality, between marital and pre- or extramarital sexuality, and between heterosexuality and homosexuality. Men are given more rights with regard to the expression of their sexuality; women are forbidden to have extramarital sex (with their slaves) and both genders to have homosexual relationships. The combination of these paradoxical standards with modernisation leads to the current back and forth swing of sexual practices between repression and openness. Partial modernisation leads to greater sexual tolerance. But restrictive sexual standards have gathered strength and have become idealised as a result of the current radicalisation of Islam. This swing of the pendulum between repression and openness is illustrated by phenomena such as public harassment, premarital sexuality, female pleasure, prostitution, and homosexuality. Currently, Islam is not any more the only reference which provides guidance concerning sexual practices but secularisation of sexual laws is still politically unthinkable today. So the only solution is to achieve reform in the name of Islam, through the reinterpretation of repressive holy texts. PMID:20441406

Dialmy, Abdessamad

2010-06-01

230

The Development of Sexual Identity.  

ERIC Educational Resources Information Center

|Examines traditional sexual orientation theories, cultural understandings of sexuality, and the emergence of queer theory. Discusses how sexual identity can open new learning pathways for adults. (SK)|

Edwards, Kathleen; Brooks, Ann K.

1999-01-01

231

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.

Morrow, Edward H; Pitcher, Trevor E

2003-01-01

232

Classification of thoracic and lumbar spine fractures: problems of reproducibility  

Microsoft Academic Search

Reproducibility of fracture classification systems in general has been a matter of controversy. The reproducibility of spinal fracture classifications has not been sufficiently studied. We studied the inter-observer and intra-observer reproducibility of the Magerl (AO) classification using radiograms, CTs and MRIs of 53 patients. We compared this classification with the older and simpler Denis classification. Five observers classified the fractures,

F. C. Oner; L. M. P. Ramos; R. K. J. Simmermacher; P. T. D. Kingma; C. H. Diekerhof; W. J. A. Dhert; A. J. Verbout

2002-01-01

233

Reproducibility of pacing profiles in competitive swimmers.  

PubMed

This study aimed at determining the reproducibility of pacing profiles (PP) during simulated swimming trials as well as the comparison between simulated and real competitions (RC). Sixteen competitive front crawl swimmers (7 females, 9 males) performed 2 × 200 m, 2 × 400 m and 2 × 800 m tests, each test 7 days apart. All 100 m split (ST) and total times (TT) were recorded (additionally 50 m ST for the 200 m bouts). The PP of one RC within a maximum of 8 weeks before or after data acquisition was used for comparison. No difference was observed between test and retest for TT (p<0.16). Coefficients of variation (CV) for all ST during 800 m were between 0.9 and 1.8% (standard error of measurement (SEM)=0.6-2.1 s), except for the last 2 sections (CV=2.5% and 2.9%). During 400 m and 200 m, CV was below 1.7% for each section (SEM=0.4-1.7 s). Mean differences between test and retest ranged from 1.8 s (Cl: 0.1-3.4 s) in the 400 m bouts to 4.1 s (Cl: 1.3-9.5 s) for the 800 m races. Although section times were faster during all sections of RC compared to SC, PP was similar during both trials (p>0.22). However, swimmers were faster in each section during RC. In conclusion, PP seem stable, at least during the first three quarters of the race. Furthermore, simulated trials seem to be an acceptable model to analyse PP in competitive swimming. PMID:22972249

Skorski, S; Faude, O; Rausch, K; Meyer, T

2012-09-12

234

Is My Network Module Preserved and Reproducible?  

PubMed Central

In many applications, one is interested in determining which of the properties of a network module change across conditions. For example, to validate the existence of a module, it is desirable to show that it is reproducible (or preserved) in an independent test network. Here we study several types of network preservation statistics that do not require a module assignment in the test network. We distinguish network preservation statistics by the type of the underlying network. Some preservation statistics are defined for a general network (defined by an adjacency matrix) while others are only defined for a correlation network (constructed on the basis of pairwise correlations between numeric variables). Our applications show that the correlation structure facilitates the definition of particularly powerful module preservation statistics. We illustrate that evaluating module preservation is in general different from evaluating cluster preservation. We find that it is advantageous to aggregate multiple preservation statistics into summary preservation statistics. We illustrate the use of these methods in six gene co-expression network applications including 1) preservation of cholesterol biosynthesis pathway in mouse tissues, 2) comparison of human and chimpanzee brain networks, 3) preservation of selected KEGG pathways between human and chimpanzee brain networks, 4) sex differences in human cortical networks, 5) sex differences in mouse liver networks. While we find no evidence for sex specific modules in human cortical networks, we find that several human cortical modules are less preserved in chimpanzees. In particular, apoptosis genes are differentially co-expressed between humans and chimpanzees. Our simulation studies and applications show that module preservation statistics are useful for studying differences between the modular structure of networks. Data, R software and accompanying tutorials can be downloaded from the following webpage: http://www.genetics.ucla.edu/labs/horvath/CoexpressionNetwork/ModulePreservation.

Langfelder, Peter; Luo, Rui; Oldham, Michael C.; Horvath, Steve

2011-01-01

235

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

2009-01-07

236

Two female-specific DSX proteins are encoded by the sex-specific transcripts of dsx, and are required for female sexual differentiation in two wild silkmoth species, Antheraea assama and Antheraea mylitta (Lepidoptera, Saturniidae).  

PubMed

doublesex (dsx) is the bottom most gene of the sex-determination cascade of Drosophila melanogaster. The pre-mRNA of dsx splices to produce male- and female-specific transcripts which code for the male- and female-specific proteins, respectively. dsx homologues have been characterized from different (many in Diptera, two in Hypmenoptera and only one in Lepidoptera) insect species. Sex-specific splice forms of dsx pre-mRNA in all these species code for one male- and one female-specific DSX proteins, which regulate the downstream target genes responsible for sex-specific characters. In the present study we have cloned and characterized the dsx homologues from two saturniid silkmoths, Antheraea assama and Antheraea mylitta. The divergence time between Saturniidae and Bombycidae to which the domesticated silkworm, Bombyx mori belongs is estimated to be around 160.9 MY. Interestingly, the dsx pre-mRNA of these wild silkmoths sex-specifically splices to generate multiple splice variants. On the basis of their open reading frame (ORF) and conceptual translation, two female-specific (DSX(F1) and DSX(F2)) and one male-specific (DSX(M)) proteins could be inferred, in both the moths. Presence or absence of a 15 bp stretch within the ORF of the two groups of female-specific transcripts resulted in the production of two distinct female-specific DSX proteins. The sex-specific DSX proteins have common amino-terminal sequence but sex-specific carboxy termini. The two female-specific DSX proteins (DSX(F1) and DSX(F2)) share common DNA binding domain (DM domain) and oligomerization domain (OD domain) and differ only at their extreme C-termini by 21aa. Functional analysis of dsx transcripts in A. assama by dsRNA mediated knock-down resulted in complete abolition of expression of vitellogenin and hexamerin genes, the direct targets of the DSX proteins, irregular differentiation of gonads, and drastic reduction in fecundity and hatchability. Together, these results suggest the involvement of both the female-specific DSX proteins in the process of female sexual differentiation. Further, conservation of the 4th exon sequence, especially the PESS sequence responsible for the sex-specific splicing of Bmdsx in the female-specific transcripts of Aadsx and Amydsx, indicated the existence of a common mechanism of sex-specific splicing of dsx homologues in silkmoths. To our knowledge this is the first report of existence of multiple splice forms of dsx pre-mRNA encoding two female-specific DSX proteins. PMID:20633649

Shukla, J N; Nagaraju, J

2010-07-13

237

Sexual size dimorphism predicts rates of sequence evolution of SPerm Adhesion Molecule 1 (SPAM1, also PH-20) in monkeys, but not in hominoids (apes including humans).  

PubMed

Based on a dataset comprising coding DNA sequences of 23 anthropoid primates, we herein investigate if rates of sequence evolution of SPerm Adhesion Molecule1 (SPAM1, also PH-20), which participates in sperm-egg interaction, is lower in more sexually dimorphic species. For comparison, we analyze sequence evolution of apolipoproteinA-IV (APOA4) and apolipoprotein A-V (APOA5), which should evolve under less or even no sexual selection given their expression in blood, digestive tract, liver, and lungs. Regression analyses provides significant support for a negative dependence of SPAM1 derived branch-specific ratios of non-synonymous to synonymous substitution rates (dN/dS) on sexual size dimorphism (SSD) in a subsample comprising New World and Old World monkeys. We moreover observed a tendency for a positive correlation of substitution rates of SPAM1 with relative testes weight (RTW) and significantly lowered dN/dS estimates in uni-male and uni-male/multi-male breeding monkeys. Importantly, the pattern was not reproduced when analyzing partial APOA4 and APOA5 sequences. These findings illustrate that different levels of sperm competition, probably fueled by female cryptic choice, account for species-specific sequence evolution of SPAM1 in monkeys. Remarkably, present data do not support a correlation of species-specific sequence evolution of SPAM1 with sexual selection levels in hominoids (apes including humans). This can partly be ascribed to a relaxation of functional constraint of SPAM1 in some hominoid species. Additional factors confounding regression analyses specifically in hominoids might be higher levels of sperm competition than reflected by SSD and RTW in some species, a rather strong effect of female mate choice on paternity rates in others, and - in particular in humans - socio-cultural factors not measurable by SSD and RTW. PMID:22197807

Prothmann, Andreas; Laube, Irina; Dietz, Johanna; Roos, Christian; Mengel, Katja; Zischler, Hans; Herlyn, Holger

2011-12-14

238

Reproduce and die! Why aging? Part I.  

PubMed

In multi-cellular organisms--and hence also in man--aging and dying is the fate of the soma, i.e., the body proper; germ cells are--at least in principle--immortal. As the soma can be considered to be the "service compartment" of the germ cells, it loses its function once a species' phase of reproduction is over. Hence, there is an intimate relationship between reproduction and aging, and therefore also between a species' reproductive strategy and aging: there has been no selection for maintenance of the soma beyond the reproductive phase of life (when there is no reproduction, there is also no natural selection). As a consequence, mechanisms, important for maintenance of the soma during the reproductive phase, increasingly begin to fail once this phase is over, resulting in an accumulation of all kinds of pathology and genetic errors, rendering an individual increasingly more prone to a variety of (internal and external) attacks. In the end, the soma collapses, be it due to organ failure, a neoplasm or to a final external push, e.g., an infection. PMID:15962724

Schuiling, Gerard A

2005-03-01

239

Reproducibility of a life-cycle toxicity test with Daphnia magna  

SciTech Connect

Standardized chronic life-cycle toxicity testing procedures for aquatic species are described. The reproducibility of chronic toxicity and points using the static-renewal method with Daphnia magna are investigated. The objectives were to determine if the lowest rejected concentrations tested (LRCTs) obtained for six different toxicity criteria in static-renewal tests with acridine were reproducible over time and to determine the relative sensitivity and variability of the toxicity criteria. Two of the six toxicity criteria, numbers of young per brood and the young produced per female, were found to be reliable and sensitive for estimating the LRCT for acridine to D. magna. (RJC)

Parkhurst, B.R.; Forte, J.L.; Wright, G.P.

1981-01-01

240

Reproducibility of dobutamine digital stress echocardiography.  

PubMed

The aim of this study was to investigate the temporal variability and interobserver agreement of dobutamine digital stress echocardiography. We performed two dobutamine stress echocardiographic studies (dobutamine up to 40 micrograms/kg/min and atropine up to 1 mg) in 15 patients with previous myocardial infarction at a mean of 19 days apart. Two observers assessed the wall motion using a six-point score in a 16-segment model and calculated the wall motion score index at rest and at peak stress by using a quad screen display. Analysis of the wall motion was performed separately on the day after each dobutamine stress test (analysis A), and all images from the serial studies in the same patient were simultaneously retrieved and compared side-by-side in the same view (analysis B). The mean values of heart rate and blood pressure were comparable for each in the two studies except for the heart rate at rest. Regarding the presence and absence of positive findings of dobutamine stress echocardiography, interobserver agreement was 93% (70% to 99% with 95% confidence limits, kappa value 0.86) in the patients and 93% (70% to 99% with 95% confidence limits, kappa value 0.80) in the three major vascular regions with the use of analysis A. these values did not improve with the use of analysis B. The agreement of the temporal variability was 93% (70% to 99% with 95% confidence limits, kappa value 0.86) in the patients and 84% (71% to 92% with 95% confidence limits, kappa value 0.66) in the vascular regions with the use of analysis A. These values further improved with the use of analysis B. With the comparison of the wall motion score index, interobserver variability showed a correlation coefficient of 0.88 at rest and 0.90 at peak stress with analysis A and 0.78 and 0.82, respectively, with analysis B. Corresponding analysis of temporal variability showed correlation coefficients of 0.99 at rest and 0.99 at peak stress when both analysis were used. Although dobutamine digital stress echocardiography has good reproducibility and negligible interobserver variability, even if the digital quad screen format is used, it requires strict standardization of the reading criteria and the objective measurements of wall motion in the expansion of this test to the evaluation of the changes in left ventricular function during more than two serial studies in the same patient. PMID:9168356

Takeuchi, M; Sonoda, S; Miura, Y; Kuroiwa, A

1997-05-01

241

Inappropriate sexual behavior.  

PubMed

Inappropriate sexual behavior, or sexually aggressive behavior, is a term which encompasses a variety of behaviors, including obscene gesturing, touching or hugging another person, exposing body parts or disrobing, and masturbating in public. Inappropriate sexual behavior often elicits feelings of anxiety, embarrassment, or unease in the caregiver and the result is often disruption in continuity of care for the patient. The cause of inappropriate sexual behavior varies among individuals and careful assessment of the etiology of the behavior is the first essential step in intervening. Nursing interventions focus upon providing opportunities for expression of appropriate sexual behavior while attempting to extinguish inappropriate sexual behavior. PMID:8954388

Philo, S W; Richie, M F; Kaas, M J

1996-11-01

242

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.

243

When Is Sexual Counseling Helpful?  

MedlinePLUS

... Physical Side Effects » Sexual Side Effects in Men » Sexuality for the Man with Cancer » When is sexual ... saved articles window. My Saved Articles » My ACS » Sexuality for the Man With Cancer + - Text Size Download ...

244

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.

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

2009-01-01

245

Sexual selection explains Rensch's rule of allometry for sexual size dimorphism  

Microsoft Academic Search

In 1950, Rensch first described that in groups of related species, sexual size dimorphism is more pronounced in larger species. This widespread and fundamental allometric relationship is now commonly referred to as 'Rensch's rule'. However, despite numerous recent studies, we still do not have a general explanation for this allometry. Here we report that patterns of allometry in over 5300

James Dale; Peter O. Dunn; Jordi Figuerola; Terje Lislevand; Tamás Székely; Linda A. Whittingham

2007-01-01

246

Fitness-associated sexual reproduction in a filamentous fungus.  

PubMed

Sex is a long-standing evolutionary enigma. Although the majority of eukaryotes reproduce sexually at least sometimes [1-3], the evolution of sex from an asexual ancestor has been difficult to explain because it requires sexually reproducing lineages to overcome the manifold costs of sex, including the destruction of favorable gene combinations created by selection [4, 5]. Conditions for the evolution of sex are much broader if individuals can reproduce either sexually or asexually (i.e., facultative sex) and allocate disproportionately more resources to sex when their fitness is low (fitness-associated-sex or FAS [6-10]). Although facultatively sexual organisms have been shown to engage in more sex when stressed [11], direct evidence for FAS is lacking. We provide evidence using 53 genotypes of the filamentous fungus Aspergillus nidulans in a reciprocal transplant experiment across three environments. Different genotypes achieved highest fitness in different environments and genotypes invested relatively more in sex in environments in which their fitness was lower, showing that allocation to sexual reproduction is a function of how well-adapted a genotype is to its environment. FAS in A. nidulans is unlikely to have evolved as a strategy to resist or avoid stress because asexual spores are more dispersive and equally resistant [12, 13]. PMID:20598542

Schoustra, Sijmen; Rundle, Howard D; Dali, Rola; Kassen, Rees

2010-07-01

247

SEXUAL SOCIALIZATION: A CONCEPTUAL REVIEW  

Microsoft Academic Search

This paper presents a critical review of the concept of sexual socialization. A reformulation of conceptions of sexual socialization identifies five components of the developmental process (development of sex-object preference; development of gender roles; development of a gender identity; acquisition of sexual skills, knowledge, and values; and development of sexual attitudes). Sexual socialization, also referred to as sexualization, is defined

GRAHAM B. SPANIER

1977-01-01

248

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

249

Sexual selection and reproductive careers in mandrills ( Mandrillus sphinx )  

Microsoft Academic Search

In sexually dimorphic, polygynous species, where males provide little parental care and competition between males for access to fertile females is high, sexual selection theory predicts sex differences in age-specific reproductive output and mortality profiles, and greater variance in lifetime reproductive success in males than in females. We examined age-specific reproductive output, mortality patterns and the extent and causes of

Joanna M. Setchell; Marie Charpentier; E. Jean Wickings

2005-01-01

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

Signification of the sexualizing substance produced by the sexualized planarians.  

PubMed

Asexual worms of an exclusively fissiparous strain (the OH strain) of the planarian Dugesia ryukyuensis keep developing hermaphroditic reproductive organs and eventually undergo sexual reproduction instead of asexual reproduction, namely fission, if they are fed with sexually mature worms of an exclusively oviparous planarian, Bdellocephala brunnea, suggesting that the sexually mature worms has a sexualizing substance(s). The fully sexualized worms no longer need the feeding on sexual worms to maintain the sexuality. Here, we demonstrate that the sexualized worms produce enough of their own sexualizing substance similar to that contained in B. brunnea. In case of surgical ablation of the sexualized worms, the fragments with sexual organs regenerate to become sexual, while those without sexual organs, namely head fragments, regenerate to return to the asexual state. The asexual regenerants from the sexualized worms are also fully sexualized by being fed with B. brunnea. Additionally, it was reported that head region in sexually mature worms lacks the putative sexualizing substance necessary for complete sexualization (Sakurai, 1981). These results suggest that the fragments without sexual organ lack enough of an amount of the putative sexualizing substance and the sexuality is maintained by the sexualizing substance contained in the sexualized worms. PMID:12130794

Kobayashi, Kazuya; Arioka, Sachiko; Hase, Sumitaka; Hoshi, Motonori

2002-06-01

252

Sexual Assault against Females  

MedlinePLUS

... to Women - Return from War - PTSD and Communities - PTSD Research - Mobile Apps - Páginas en Español - Videos - Web Links PROFESSIONAL ABOUT US PTSD Awareness Month Sexual Assault against Females Sexual Assault ...

253

Sexual Health Problems  

MedlinePLUS

... common sexual problems and their solutions Changes in sex drive, mismatched desire Fatigue or feeling ill can ... is essential to working through these problems. Discussing sexual health Because our sex lives are usually private, talking ...

254

Overview of Sexuality  

MedlinePLUS

... Disorder Topics in Sexuality Overview of Sexuality Gender Identity Paraphilias Merck Manual > Patients & Caregivers > Mental Health Disorders > ... Top Previous: Definition of Eating Disorders Next: Gender Identity Audio Figures Photographs Pronunciations Sidebar Tables Videos Copyright © ...

255

Sexual Health (Men)  

MedlinePLUS

... Living with Diabetes > Complications > Men's Health > Sexual Health Sexual Health Listen Sex is an important part of life and relationships. But diabetes can affect a man's sex life. It is important to understand that there ...

256

Sexual problems overview  

MedlinePLUS

... Review all medications, both prescription and over-the-counter, for possible side effects that relate to sexual dysfunction. Avoiding drug and alcohol abuse will also help prevent sexual dysfunction. Couples who ...

257

Sexual Violence and Adolescents.  

National Technical Information Service (NTIS)

The purpose of this paper is to review the current state of the science regarding sexual violence occurring in adolescent dating and acquaintance relationships. Sexual violence occurring at the hand of a family member, family friend, or stranger will not ...

B. Rosenbluth H. Harner

2003-01-01

258

Sexuality in Later Life  

MedlinePLUS

... normal operations can be found at USA.gov . Sexuality in Later Life Many people want and need ... Depression can be treated. What Else May Cause Sexuality Problems? Surgery. Many of us worry about having ...

259

Female sexual health.  

PubMed

Many aspects of sexual health relate to either preventative medicine (contraception) or managing normal physiological states (pregnancy, menopause). This article looks at some of the emergency aspects of female sexual health including genital tract trauma and genital infections. PMID:12786642

Bryan, Sheila

2003-06-01

260

Female sexual dysfunction  

Microsoft Academic Search

Female sexual dysfunction is a common problem with detrimental effects on woman’s quality of life. It also has an economical\\u000a and societal impact. It is defined as disorders of sexual desire, arousal, orgasm, and sexual pain, which lead to personal\\u000a distress. The etiology of sexual dysfunction is frequently multifactorial as it relates to general physical and mental well-being,\\u000a quality of

Erdogan Aslan; Michelle Fynes

2008-01-01

261

Sexual (Lust) Homicide  

Microsoft Academic Search

This chapter discusses the historical definitional origins of sexual homicide (lust murder), the dynamics of sexual homicide\\u000a injury, offense definition constructs and their limitations, and key presumptions of injuries associated with sexual homicide\\u000a offense models. The chapter concludes by arguing for the clarification of concepts, characterizations, linkages, and research\\u000a into the offense dynamics and offender motivations of sexual (lust) homicides.

Janet McClellan

262

Profiling Sexual Fantasy  

Microsoft Academic Search

\\u000a Criminal profiling attempts to understand the behavioral and personality characteristics of an offender and has gained increasing\\u000a recognition as a valuable investigative procedure. This chapter investigates sexual fantasy within the context of sexual crimes.\\u000a It opens by providing an account of sexual fantasy, its nexus with sexually aberrant behavior, and how it has been utilized\\u000a within the domain of criminal

Dion Gee; Aleksandra Belofastov

263

Sexual Dysfunction in Women  

PubMed Central

Sexual dysfunction takes place in the context of women's lives and affects their sexuality and self-esteem. Awareness of these influences are vital to the management of the dysfunction and the promotion of positive sexuality. The family physician's contribution to both the prevention and management of sexual concerns includes an awareness of societal influences and facilitation of a woman's sense of her own power and control over her life.

Brown, Pamela

1989-01-01

264

Sexual Relationships with Educators  

Microsoft Academic Search

This study of sexually oriented relationships between educators\\/field instructors and their students\\/supervisees was conceptualized to add to existing knowledge of the incidence and impact on master of social work students of sexually intimate relationships, sexual advances, and first-hand knowledge of such relationships. The present study gathers data from male and female subjects regarding sexual contact experiences with educators\\/field instructors during

Timothy Barnett-Queen

1999-01-01

265

Religiosity, spirituality, sexual attitudes, and sexual behaviors among college students.  

PubMed

The purpose of this study was to determine whether religiosity, spirituality, and sexual attitudes accounted for differences in sexual behaviors among college students. The sample included 960 college students enrolled at four northeastern colleges. Results indicated differences in sexual attitudes, religiosity, and spirituality by gender. Moreover, sexual attitudes, religiosity, and spirituality were associated with sexual behaviors among college students. Sexual behaviors among males were influenced by their sexual attitudes, religiosity, and spirituality, while for females, their sexual behaviors were mostly influenced by their sexual attitudes. College health professionals can use these findings when discussing sexual practices with students. PMID:21822743

Luquis, Raffy R; Brelsford, Gina M; Rojas-Guyler, Liliana

2012-09-01

266

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

267

Ecology and sexual selection: evolution of wing pigmentation in calopterygid damselflies in relation to latitude, sexual dimorphism, and speciation.  

PubMed

Abstract Our knowledge about how the environment influences sexual selection regimes and how ecology and sexual selection interact is still limited. We performed an integrative study of wing pigmentation in calopterygid damselflies, combining phylogenetic comparative analyses, field observations and experiments. We investigated the evolutionary consequences of wing pigmentation for sexual dimorphism, speciation, and extinction and addressed the possible thermoregulatory benefits of pigmentation. First, we reconstructed ancestral states of male and female phenotypes and traced the evolutionary change of wing pigmentation. Clear wings are the ancestral state and that pigmentation dimorphism is derived, suggesting that sexual selection results in sexual dimorphism. We further demonstrate that pigmentation elevates speciation and extinction rates. We also document a significant biogeographic association with pigmented species primarily occupying northern temperate regions with cooler climates. Field observations and experiments on two temperate sympatric species suggest a link between pigmentation, thermoregulation, and sexual selection, although body temperature is also affected by other phenotypic traits such as body mass, microhabitat selection, and thermoregulatory behaviors. Taken together, our results suggest an important role for wing pigmentation in sexual selection in males and in speciation. Wing pigmentation might not increase ecological adaptation and species longevity, and its primary function is in sexual signaling and species recognition. PMID:24107378

Svensson, Erik I; Waller, John T

2013-09-16

268

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.

269

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.

270

Risk, individual differences, and environment: an Agent-Based Modeling approach to sexual risk-taking.  

PubMed

Risky sexual behaviors, including the decision to have unprotected sex, result from interactions between individuals and their environment. The current study explored the use of Agent-Based Modeling (ABM)-a methodological approach in which computer-generated artificial societies simulate human sexual networks-to assess the influence of heterogeneity of sexual motivation on the risk of contracting HIV. The models successfully simulated some characteristics of human sexual systems, such as the relationship between individual differences in sexual motivation (sexual excitation and inhibition) and sexual risk, but failed to reproduce the scale-free distribution of number of partners observed in the real world. ABM has the potential to inform intervention strategies that target the interaction between an individual and his or her social environment. PMID:22042161

Nagoski, Emily; Janssen, Erick; Lohrmann, David; Nichols, Eric

2011-11-01

271

Human fertility variation, size-related obstetrical performance and the evolution of sexual stature dimorphism  

Microsoft Academic Search

In several animal species, change in sexual size dimorphism is a correlated response to selection on fecundity. In humans, di¡ erent hypotheses have been proposed to explain the variation of sexual dimorphism in stature, but no consensus has yet emerged. In this paper, we evaluate from a theoretical and an empiricalpoint of view the hypothesis that the extent of sexual

J.-F. Guegan; A. T. Teriokhin; F. Thomas

2000-01-01

272

Accurate measurements of dynamics and reproducibility in small genetic networks  

PubMed Central

Quantification of gene expression has become a central tool for understanding genetic networks. In many systems, the only viable way to measure protein levels is by immunofluorescence, which is notorious for its limited accuracy. Using the early Drosophila embryo as an example, we show that careful identification and control of experimental error allows for highly accurate gene expression measurements. We generated antibodies in different host species, allowing for simultaneous staining of four Drosophila gap genes in individual embryos. Careful error analysis of hundreds of expression profiles reveals that less than ?20% of the observed embryo-to-embryo fluctuations stem from experimental error. These measurements make it possible to extract not only very accurate mean gene expression profiles but also their naturally occurring fluctuations of biological origin and corresponding cross-correlations. We use this analysis to extract gap gene profile dynamics with ?1?min accuracy. The combination of these new measurements and analysis techniques reveals a twofold increase in profile reproducibility owing to a collective network dynamics that relays positional accuracy from the maternal gradients to the pair-rule genes.

Dubuis, Julien O; Samanta, Reba; Gregor, Thomas

2013-01-01

273

Sexually transmitted proctitis  

PubMed Central

Sexually transmitted infections such as chlamydia, gonorrhoea, herpes simplex virus and syphilis commonly present with rectal symptoms. Recent outbreaks of lymphogranuloma venereum among homosexual men throughout Europe highlight the need to consider sexually transmitted infections in the differential diagnosis of proctitis. This article examines the causative organisms, clinical features, diagnosis and treatment of sexually transmitted proctitis.

Hamlyn, E; Taylor, C

2006-01-01

274

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

275

Sexual Behavior in Adolescence  

ERIC Educational Resources Information Center

Surveys conducted between the 1930's and 1970's on the sexual behavior of adolescents indicate the following: (1) older adolescents are more sexually experienced now than in earlier generations; (2) there has been a greater increase in incidence of premarital sex for females than males; and (3) there is a trend toward earlier sexual experience for…

Hopkins, J. Roy

1977-01-01

276

Sexual Assault Prevention Handbook.  

ERIC Educational Resources Information Center

|This publication is designed to educate men and women about sexual assault. The goals are to encourage people to become involved in their own protection and to make them better informed and able to deal with sexual assaults when they do occur. Facts about sexual assault are presented, including descriptions of rapists, rape victims, and rape…

Missouri Governor's Commission on Crime, Jefferson.

277

Editorial: Subaltern sexualities  

Microsoft Academic Search

Anyone who is passionate about women, gender and development in African contexts needs to interrogate discourses about African sexuality. These dis- courses have long histories of academic authority that have assisted in ensuring that hegemonic discourses about sexuality were at the heart of the continent's underdevelopment during colonialism. And as contributors to Feminist Africa 5 (on Sexual Cultures) point out,

Elaine Salo; Pumla Dineo Gqola

278

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

279

Discovering Sexuality in Dostoevsky  

Microsoft Academic Search

Most discussions of sexuality in the work of Dostoevsky have been framed in Freudian terms. But Dostoevsky himself wrote about sexuality from a decidedly pre-Freudian perspective. By looking at the views of human sexual development that were available in Dostoevsky's time and that he, an avid reader and observer of his own social context, absorbed and reacted to, Susanne Fusso

Susanne Fusso

2006-01-01

280

Understanding sexual homicide  

Microsoft Academic Search

Sexual homicide is a crime that receives much media attention, but one that still has a relatively small research base compared to other crimes. Although the idea of someone deriving sexual gratification from or during the killing of another is an anathema to many, forensic professionals need to understand sexual homicide and the range of circumstances and motivations that lie

Paul V. Greenall

2011-01-01

281

Sexual orientation discrimination  

Microsoft Academic Search

Al though we have legislation that, at least in theory, protects employees from discrimination, discrimination still occurs. Title VII of the Civil Rights Act of 1964 prohibits discrimination in all areas of employment on the basis of race, colour, religion, sex or national origin. This includes sexual harassment, a form of discrimination which involves “unwelcome sexual advances, requests for sexual

Gail A. Dawson

2005-01-01

282

Depression and sexual dysfunction  

Microsoft Academic Search

Adequate sexual expression is an essential part of many human relationships, and may enhance quality of life and provide a sense of physical, psychological and social well-being. Epidemiological and clinical studies show that depression is associated with impairments of sexual function and satisfaction, even in untreated patients. Most antidepressant drugs have adverse effects on sexual function, but accurate identification of

David S Baldwin

283

What is Sexual Addiction?  

Microsoft Academic Search

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

Stephen B. Levine

2010-01-01

284

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

285

Reproducibility of a Triaxial Seismic Accelerometer (DynaPort)  

Microsoft Academic Search

VAN HEES, V. T., S. M. SLOOTMAKER, G. DE GROOT, W. VAN MECHELEN, and R. C. VAN LUMMEL. Reproducibility of a Triaxial Seismic Accelerometer (DynaPort). Med. Sci. Sports Exerc., Vol. 41, No. 4, pp. 810-817, 2009. Purpose: To examine the reproducibility of a triaxial seismic accelerometer under controlled conditions and real-life conditions. Methods: Instrumental reproducibility was examined using a shaker

VINCENT T. VAN HEES; SANDER M. SLOOTMAKER; GERT DE GROOT; WILLEM VAN MECHELEN; ROB C. VAN LUMMEL

2009-01-01

286

Female Sexual Arousal in Amphibians  

PubMed Central

Rather than being a static, species specific trait, reproductive behavior in female amphibians is variable within an individual during the breeding season when females are capable of reproductive activity. Changes in receptivity coincide with changes in circulating estrogen. Estrogen is highest at the point when females are ready to choose a male and lay eggs. At this time female receptivity (her probability of responding to a male vocal signal) is highest and her selectivity among conspecific calls (measured by her probability of responding to a degraded or otherwise usually unattractive male signal) is lowest. These changes occur even though females retain the ability to discriminate different acoustic characteristics of various conspecific calls. After releasing her eggs, female amphibians quickly become less receptive and more choosy in terms of their responses to male sexual advertisement signals. Male vocal signals stimulate both behavior and estrogen changes in amphibian females making mating more probable. The changes in female reproductive behavior are the same as those generally accepted as indicative of a change in female sexual arousal leading to copulation. They are situationally triggered, gated by interactions with males, and decline with the consummation of sexual reproduction with a chosen male. The changes can be triggered by either internal physiological state or by the presence of stimuli presented by males, and the same stimuli change both behavior and physiological (endocrine) state in such a way as to make acceptance of a male more likely. Thus amphibian females demonstrate many of the same general characteristics of changing female sexual state that in mammals indicate sexual arousal.

Wilczynski, Walter; Lynch, Kathleen S.

2010-01-01

287

Sexual satisfaction and sexual self?disclosure within dating relationships  

Microsoft Academic Search

This study examined dating individuals' self?disclosure about their sexual likes and dislikes to their partner. Forty?seven college men and 52 college women in a dating relationship of 3 to 36 months completed a questionnaire measuring sexual exchange variables, sexual satisfaction, relationship satisfaction, sexual communication satisfaction, and sexual and non?sexual self?disclosure with their partner. Both sexual and nonsexual self?disclosure were at

E. Sandra Byers; Stephanie Demmons

1999-01-01

288

Necrophilia and sexual homicide.  

PubMed

A closed case-file review of 211 sexual homicides identified 16 cases of necrophilia. The results of this unique descriptive study of necrophilia associated with sexual homicide provide information on crime-scene locations, methods of killing, body disposition, premortem sexual assault, specifics of the necrophilic acts, methods of victim abduction, and motivational dynamics. The findings suggest that the most common explanation for necrophilia-the offender's desire to have an unresisting partner-may not always be applicable in cases where this rare paraphilia is connected to sexual murder. The possibility of using crime-scene behaviors in these cases to investigate serial sexual murders is offered. PMID:20102474

Stein, Michelle L; Schlesinger, Louis B; Pinizzotto, Anthony J

2010-01-25

289

Sexual misconduct and enactment.  

PubMed

Sexual misconduct remains a significant problem in the behavioral health professions. Although it is tempting to view sexual misconduct as perpetrated by "bad" clinicians against patients who are "victims," this is an oversimplification of a complex problem. In this article, the author explores the psychoanalytic concept of enactment as a mechanism that can lead well-meaning clinicians to engage in sexual misconduct; defines enactment and differentiates it from near neighbor phenomena; uses case examples to illustrate how enactments may lead to sexual misconduct or may offer opportunities to deepen and enhance psychotherapeutic work; and offers recommendations for prevention of sexual misconduct. PMID:10523431

Plakun, E M

1999-01-01

290

Sexual Misconduct and Enactment  

PubMed Central

Sexual misconduct remains a significant problem in the behavioral health professions. Although it is tempting to view sexual misconduct as perpetrated by “bad” clinicians against patients who are “victims,” this is an oversimplification of a complex problem. In this article, the author explores the psychoanalytic concept of enactment as a mechanism that can lead well-meaning clinicians to engage in sexual misconduct; defines enactment and differentiates it from near neighbor phenomena; uses case examples to illustrate how enactments may lead to sexual misconduct or may offer opportunities to deepen and enhance psychotherapeutic work; and offers recommendations for prevention of sexual misconduct.

Plakun, Eric M.

1999-01-01

291

Birdsong performance and the evolution of simple (rather than elaborate) sexual signals.  

PubMed

Sexual signals are often elaborate as a result of sexual selection for signals of individual quality. Contrary to expectation, however, the elaboration of signals such as birdsong is not related to the strength of sexual selection across species. With a comparative study across wood warblers (family Parulidae), we show a compromise between advertising the performance of trills (syllable repetitions) and song complexity, which can result in the evolution of simple, rather than elaborate, song. Species with higher trill performance evolved simple songs with more extensive trilled syntax. This advertises trill performance but reduces syllable diversity in songs. These two traits are commonly sexually selected in songbirds, but indexes of sexual selection were not related to either in wood warblers. This is consistent with sexual selection targeting different traits in different species, sometimes resulting in simple signals. We conclude that the evolution of sexual signals can be unpredictable when their physiology affords multiple or, as here, opposing ways of advertising individual quality. PMID:22030736

Cardoso, Gonçalo C; Hu, Yang

2011-09-29

292

Evolution of sexual size monomorphism: the influence of passive mate guarding.  

PubMed

Some species have potential for intense mate competition yet exhibit little or no sexual size dimorphism, despite predictions from sexual selection theory. Using a conceptual model, we show the conditions for which passive mate guarding with copulatory plugs can be an alternative and more successful strategy to active (direct) guarding, reducing selection pressure on large male size. The model predicts that copulatory plugs in mammals should be favoured in species for which females have short sexual receptivity periods. Using data on 62 primate species and a phylogenetic regression approach, we show that, as predicted, copulatory plugs are negatively associated with degree of sexual dimorphism and females' sexual receptivity length. Penile spines are also significantly associated with plug use and short receptivity periods suggesting a possible offensive role in sperm competition. Results highlight that life-history characteristics, such as sexual receptivity lengths, may alter the costs and benefits of alternative male strategies and thus alter the strength of sexual selection. PMID:19486235

Dunham, A E; Rudolf, V H W

2009-05-22

293

Rates of phenotypic evolution of ecological characters and sexual traits during the Tanganyikan cichlid adaptive radiation.  

PubMed

Theory suggests that sexual traits evolve faster than ecological characters. However, characteristics of a species niche may also influence evolution of sexual traits. Hence, a pending question is whether ecological characters and sexual traits present similar tempo and mode of evolution during periods of rapid ecological divergence, such as adaptive radiation. Here, we use recently developed phylogenetic comparative methods to analyse the temporal dynamics of evolution for ecological and sexual traits in Tanganyikan cichlids. Our results indicate that whereas disparity in ecological characters was concentrated early in the radiation, disparity in sexual traits remained high throughout the radiation. Thus, closely related Tanganyikan cichlids presented higher disparity in sexual traits than ecological characters. Sexual traits were also under stronger selection than ecological characters. In sum, our results suggest that ecological characters and sexual traits present distinct evolutionary patterns, and that sexual traits can evolve faster than ecological characters, even during adaptive radiation. PMID:21848985

Gonzalez-Voyer, A; Kolm, N

2011-08-16

294

Drugs and sexual behavior.  

PubMed

This study investigated the association between drugs and sexual behavior in a sample of polydrug substance abusers recruited from several Italian therapeutic communities; participants were 90 polydrug substance abusers (opiates, cocaine, amphetamine, inhalants, marijuana/sedatives or hallucinogens abusers) who were compared with 90 nonsubstance-abusing individuals. Sexual behavior was measured by the Italian version of the Sex and the Average Woman (or Man; SAWM), a questionnaire that assesses different kind of sexual attitudes. Results showed that drug-abusing individuals are particularly inclined to search for sexual intercourse and are open to different kinds of sexual experiences; however, they have difficulties in establishing committed and deep relationships with their partners, showing signs of inhibition, affective detachment or anger. Their sexual lives are also surrounded by negative emotions, disturbing thoughts and maladjusted behaviors. The importance of integrating sexual problems into therapeutic strategies is discussed. PMID:23457886

Bruno, Antonio; Scimeca, Giuseppe; Marino, Antonio G; Mento, Carmela; Micò, Umberto; Romeo, Vincenzo M; Pandolfo, Gianluca; Zoccali, Rocco; Muscatello, Maria R A

295

Sexual Violence and the MDGs  

Microsoft Academic Search

Sexual violence is multi-faceted. Three (overlapping) categories can be distinguished: violence that is sexual in nature, gender-based violence, and sexuality-based violence. The latter refers to violence against persons because of their sexuality and\\/or their (presumed) sexual behavior. Being female, young, poor, and living in a sexually conservative culture and\\/or in conflict areas appear to be important risk factors for sexual

Ine Vanwesenbeeck

2008-01-01

296

Attempts to reproduce vacuolar myelinopathy in domestic swine and chickens.  

PubMed

Avian vacuolar myelinopathy (AVM) was first recognized as a cause of bald eagle (Haliaeetus leucocephalus) mortality in 1994 in Arkansas (USA) and has since caused over 90 bald eagle and numerous American coot (Fulica americana) mortalities in five southeastern states. The cause of AVM remains undetermined but is suspected to be a biotoxin. Naturally occurring AVM has been limited to wild waterbirds, raptors, and one species of shorebird, and has been reproduced experimentally in red-tailed hawks (Buteo jamaicensis). In this study, chickens and swine were evaluated for susceptibility to vacuolar myelinopathy with the intent of developing animal models for research and to identify specific tissues in affected coots that contain the causative agent. Additionally, submerged, aquatic vegetation, primarily hydrilla (Hydrilla verticillata), and associated material collected from a reservoir during an AVM outbreak was fed to chickens in an effort to reproduce the disease. In two separate experiments, six 4-wk-old leghorn chickens and ten 5-wk-old leghorn chickens were fed coot tissues. In a third experiment, five 3-mo-old domestic swine and one red-tailed hawk, serving as a positive control, were fed coot tissues. In these experiments, treatment animals received tissues (brain, fat, intestinal tract, kidney, liver, and/or muscle) from coots with AVM lesions collected at a lake during an AVM outbreak. Negative control chickens and one pig received tissues from coots without AVM lesions that had been collected at a lake where AVM has never been documented. In a fourth experiment, eight 3-wk-old leghorn chickens were fed aquatic vegetation material. Four chickens received material from the same lake from which coots with AVM lesions were collected for the previous experiments, and four control chickens were fed material from the lake where AVM has never been documented. Blood was collected and physical and neurologic exams were conducted on animals before and once per week during the trials. All animals were sacrificed and necropsies were performed on Day 29 of feeding, with the exception of one treated chicken that was sacrificed and necropsied on Day 15 of feeding. Microscopic lesions of vacuolar myelinopathy were present in the red-tailed hawk and five chickens that received a mixture of all tissues and two chickens that received only gastrointestinal tissues of coots with AVM lesions. Three of four treated chickens in the aquatic vegetation trial developed vacuolar lesions. None of four treatment pigs or any of the negative control animals developed vacuolar lesions. Chickens are susceptible to AVM and may serve as a useful animal model for future studies. Swine may be refractory to AVM or not affected by AVM at the same dose as are chickens and red-tailed hawks. The causative agent of AVM in affected coots is associated with the gastrointestinal tissues. Furthermore, AVM can be reproduced in chickens via ingestion of aquatic vegetation and associated materials collected from a lake during an AVM outbreak. The cause of AVM is most likely present in the materials associated with submerged vegetation because the vegetation itself (hydrilla) was the same at our AVM-positive and AVM-negative sites. PMID:15465715

Lewis-Weis, Lynn A; Gerhold, Richard W; Fischer, John R

2004-07-01

297

Reproducibility along a 10 cm vertical visual analogue scale  

Microsoft Academic Search

Reproducibility along a vertical 10 cm visual analogue scale (VAS) was investigated. Eight normal volunteers attempted to duplicate a set of marked VAS. There was a tendency to estimate too high on the scale, and reproducibility was found to be variable along its length. This indicates that the error involved in the use of VASs is even more complex than

J S Dixon; H A Bird

1981-01-01

298

Biomarker reproducibility in exhaled breath condensate collected with different condensers  

Microsoft Academic Search

Optimal collection and analysis of exhaled breath condensate (EBC) are prerequisites for standardisation and reproducibility of assessments. The present study aimed to assess reproducibility of EBC volume, hydrogen peroxide (H2O2), 8-isoprostane and cytokine measurements using different condensers, including a newly developed glass condenser. At four points in time, 30 healthy subjects performed sequential EBC collections randomly using the following four

P. P. Rosias; C. M. Robroeks; A. Kester; G. J. den Hartog; W. K. Wodzig; G. T. Rijkerse; L. J. Zimmermann; C. P. van Schayck; Q. Jobsis; E. Dompeling

2008-01-01

299

Making neurophysiological data analysis reproducible: Why and how?  

Microsoft Academic Search

Reproducible data analysis is an approach aiming at complementing classical printed scientific articles with everything required to independently reproduce the results they present. “Everything” covers here: the data, the computer codes and a precise description of how the code was applied to the data. A brief history of this approach is presented first, starting with what economists have been calling

Matthieu Delescluse; Romain Franconville; Sébastien Joucla; Tiffany Lieury; Christophe Pouzat

300

Self-reproducing learning, data mining and intelligent predictive systems  

Microsoft Academic Search

Self-reproducing learning mechanism is a type of learning technique which was developed from our intelligent predictive systems. It is very useful to be applied to our Lotto Predictive System to increase the performance of prediction. Self-reproducing learning technique is part of our knowledge discovery data mining tools on Lotto predictive system. Lotto predictive system is also based on human super

James Kuodo Huang

2005-01-01

301

Bridging Functional MR Images and Scientific Inference: Reproducibility Maps  

Microsoft Academic Search

Historically, reproducibility has been the sine qua non of experimental findings that are considered to be scientifically useful. Typically, findings from functional magnetic resonance imaging (fMRI) studies are assessed with statistical parametric maps (SPMs) using a p value threshold. However, a smaller p value does not imply that the observed result will be reproducible. In this study, we suggest interpreting

Michelle Liou; Hong-Ren Su; Juin-Der Lee; Philip E. Cheng; Chien-Chih Huang; Chih-Hsin Tsai

2003-01-01

302

Quantitative estimators of convergence and reproducibility of measurements  

Microsoft Academic Search

measurements. Reproducibility of measurements is estimated based on several groups of results of measurements. In [3] it is shown how one can check whether groups of experimental data satisfy reproducibility of measurements. Evidently, for this purpose, it is necessary to check the proximity of results of measurements of groups of observations as well as characteristics of their random errors. Proximity

Zh. F. Kudryashova

1993-01-01

303

Reproducibility and stability of normalized EMG measurements on musculus trapezius  

Microsoft Academic Search

The reliability of normalized EMGrms (root mean square value of the electromyographic signal) measurements from musculus trapezius were evaluated in a field study. The reproducibility and stability of the method as well as the reproducibility of the results for nine variables were examined. The variables were: static, median and peak values of the ADF (amplitude distribution function) and the total

ARNE AAR?S; MARIT B. VEIERØD; STIG LARSEN; ROLAND ØRTENGREN; OLA RO

1996-01-01

304

Amyloid beta precursor protein regulates male sexual behavior.  

PubMed

Sexual behavior is variable between individuals, ranging from celibacy to sexual addictions. Within normal populations of individual men, ranging from young to middle aged, testosterone levels do not correlate with libido. To study the genetic mechanisms that contribute to individual differences in male sexual behavior, we used hybrid B6D2F1 male mice, which are a cross between two common inbred strains (C57BL/6J and DBA/2J). Unlike most laboratory rodent species in which male sexual behavior is highly dependent upon gonadal steroids, sexual behavior in a large proportion of these hybrid male mice after castration is independent of gonadal steroid hormones and their receptors; thus, we have the ability to discover novel genes involved in this behavior. Gene expression arrays, validation of gene candidates, and transgenic mice that overexpress one of the genes of interest were used to reveal genes involved in maintenance of male sexual behavior. Several genes related to neuroprotection and neurodegeneration were differentially expressed in the hypothalamus of males that continued to mate after castration. Male mice overexpressing the human form of one of these candidate genes, amyloid beta precursor protein (APP), displayed enhanced sexual behavior before castration and maintained sexual activity for a longer duration after castration compared with controls. Our results reveal a novel and unexpected relationship between APP and male sexual behavior. We speculate that declining APP during normal aging in males may contribute to the loss of sexual function. PMID:20668181

Park, Jin Ho; Bonthius, Paul J; Tsai, Houng-Wei; Bekiranov, Stefan; Rissman, Emilie F

2010-07-28

305

Analysis of sexual dimorphism in human face  

Microsoft Academic Search

Human beings can easily distinguish between a male and a female face without much difficulty. The science of recognizing and differentiating different faces by humans is not completely understood and is still under research. Sexual dimorphism is common in humans and indeed in other species of animals as well. Significant differences between males and females exist in many aspects like

Ashok Samal; Vanitha Subramani; David Marx

2007-01-01

306

Female swordtail fish prefer symmetrical sexual signal  

Microsoft Academic Search

It has been proposed that females use the symmetry of secondary sexual traits to differentiate between potential mates. The vertical bars on male swordtail fish function as a signal that attracts females and deters rival males in one swordtail species. In addition, male courtship behaviour of mostXiphophorusspecies incorporates serial lateral presentations, which provide females with a clear opportunity to assess

MOLLY R. MORRIS; KENNETH CASEY

1998-01-01

307

Corneal confocal microscopy is efficient, well-tolerated, and reproducible.  

PubMed

In order to develop an efficient, reproducible, and well-tolerated protocol for assessing corneal innervation, 11 normal subjects underwent corneal confocal microscopy (CCM) using a Heidelberg Retinal Tomography III microscope. Five standardized locations were sampled in the left eye and one centrally in the right. The protocol was repeated 1-4?weeks later. A blinded technician measured nerve fiber length (NFL) and tortuosity coefficient (TC). The relationship between image location and NFL and TC was assessed using one-way analysis of variance, and reproducibility determined using relative intertrial variability and intraclass correlation coefficients. NFL reproducibility was maximized by averaging four or more images from the left eye, or one central image from both eyes. TC was less reproducible. CCM is a rapid, well-tolerated, and reproducible method for assessing corneal innervation. PMID:23521645

Smith, Albert Gordon; Kim, Gene; Porzio, Michael; Allen, Blaine; Koach, Margaret; Mifflin, Mark; Digre, Kathleen; Keung, Bonnie M; Singleton, John Robinson

2013-03-01

308

Sexual concerns and sexual counseling in heart failure  

Microsoft Academic Search

Patients with heart failure (HF) face significant challenges in maintaining quality of life (QOL), particularly for sexual intimacy. Although recommended for all cardiac patients, it has been suggested that few HF patients receive sexual counseling. This study explored sexual counseling needs, sexual concerns, and sexual activity using a descriptive survey with HF patients (n = 45), recruited from a HF

Mary Medina; Cynthia Walker; Elaine E. Steinke; David W. Wright; Victoria Mosack; Mohammad Hussam Farhoud

2009-01-01

309

Sexual At-Risk Behaviors of Sexually Abused Adolescent Girls  

ERIC Educational Resources Information Center

|The present study investigated sexual at-risk behaviors of sexually abused adolescent girls. Variables of interest were presence of consensual sexual activity, age at first consensual intercourse, number of sexual partners, condom use, and pregnancies. Participants were 125 sexually abused adolescent girls aged 12 to 17 years. Results showed that…

Cinq-Mars, Caroline; Wright, John; Cyr, Mireille; McDuff, Pierre

2003-01-01

310

Sexual coercion and the opportunity for sexual selection in guppies  

Microsoft Academic Search

The operational sex ratio (OSR) is believed to play a major role in determining the opportunity for sexual selection. Most studies that investigate the effects of OSR on the opportunity for sexual selection, however, ignore the important effects that OSR has on sexual coercion. Sexually coercive behaviour by males, in- cluding forceful or subversive mating tactics and sexual harassment, may

Megan L. Head; Robert Brooks

2006-01-01

311

Late Adolescent Girls' Sexual Experiences and Sexual Satisfaction  

ERIC Educational Resources Information Center

|This study presented and tested a model of sexual satisfaction for late adolescent girls. In this model, sexual self-concept and approach sexual motives were tested as predictors of adolescent girls' sexual satisfaction with their most recent experience of sexual intercourse. A total of 116 girls in 12th grade (ages 16-19) completed measures of…

Impett, Emily A.; Tolman, Deborah L.

2006-01-01

312

The Content of Sexual Fantasies for Sexual Offenders  

Microsoft Academic Search

Although the phenomenon of sexual fantasy has been extensively researched, little contemporary inquiry has investigated the content of sexual fantasy within the context of sexual offending. In this study, a qualitative analysis was used to develop a descriptive model of the phenomena of sexual fantasy during the offence process. Twenty-four adult males convicted of sexual offences provided detailed retrospective descriptions

Dion G. Gee; Grant J. Devilly; Tony Ward

2004-01-01

313

Attention Bias for Sexual Words in Female Sexual Dysfunction  

Microsoft Academic Search

Cognitive models suggest that attention processes maintain sexual dysfunction. However, few published studies have examined attention bias, and even fewer have studied female participants with sexual dysfunction. Using the Female Sexual Function Index, the authors classified undergraduates as experiencing sexual dysfunction (n = 28) or not (n = 28). The authors assessed whether participants showed attention bias for sexual words

Courtney Beard; Nader Amir

2010-01-01

314

Sexual Positions and Sexual Satisfaction of Pregnant Women  

Microsoft Academic Search

The purpose of this study was to investigate the sexual positions and sexual satisfaction of women during pregnancy. The authors sampled pregnant women (N = 215) from outpatients registered at the antepartum clinic of a medical center in northern Taiwan. The authors gathered data on recent sexual satisfaction, general sexual satisfaction, and sexual position using a self-report, structured questionnaire. The

Jian Tao Lee; Chao Ling Lin; Gwo Hwa Wan; Ching Chung Liang

2010-01-01

315

Sexual Ideology and Schooling: Towards Democratic Sexuality Education.  

ERIC Educational Resources Information Center

|This book examines the issue of sexuality education in the schools. Chapter 1, "Sexuality and Sexuality Education: Implications for the Nature of Society," discusses the controversy over the issue. Chapter 2, "Restrictive and Permissive Sexual Ideologies," provides an analytical framework for clarifying conflicts around human sexuality that…

McKay, Alexander

316

Dangerous Omissions: Abstinence-Only-until-Marriage School-Based Sexuality Education and the Betrayal of LGBTQ Youth  

ERIC Educational Resources Information Center

|To gain an understanding of how abstinence-only-until-marriage school-based sexuality education has been exclusionary, it is important to explore how heteronormativity has been endorsed, played out, and reproduced ever since school-based sexuality education has been offered in the United States. Such an exploration reveals glaring evidence that…

Elia, John P.; Eliason, Mickey J.

2010-01-01

317

Sexual partner preference in female Japanese macaques.  

PubMed

Whether animals ever exhibit a preference for same-sex sexual partners is a subject of debate. Japanese macaques represent excellent models for examining issues related to sexual preference in animals because females, in certain populations, routinely engage in both heterosexual and homosexual behavior over the course of their life spans. Multiple lines of evidence indicate that female homosexual behavior in Japanese macaques is a sexual behavior, not a sociosexual one. Additional evidence indicates that female Japanese macaques do not engage in homosexual behavior simply because acceptable male mates are unavailable or unmotivated to copulate. Patterns of sexual partner choice by female Japanese macaques that are the focus of intersexual competition indicate that females of this species choose same-sex sexual partners even when they are simultaneously presented with a motivated, opposite-sex alternative. Thus, in some populations of Japanese macaques, females prefer certain same-sex sexual partners relative to certain male mates, and vice versa. Taken together, this evidence suggests that female Japanese macaques are best characterized as bisexual in orientation, not preferentially homosexual or preferentially heterosexual. PMID:11910792

Vasey, Paul L

2002-02-01

318

Engineering preliminaries to obtain reproducible mixtures of atelocollagen and polysaccharides.  

PubMed

The critical stage in producing blends of biomacromolecules consists in the mixing of component solutions to generate homogenous diluted colloidal systems. Simple experimental investigations allow the establishment of the design rules of recipes and the procedures for preparing homogenous and compositionally reproducible mixtures. Starting from purified solutions of atelocollagen, hyaluronan and native gellan, having as low as possible inorganic salts content, initial binary and ternary mixtures can be prepared up to a total dry matter content of 0.150 g/dL, in no co-precipitating conditions. Two pH manipulation ways are feasible for homogenous mixing: (i) unbuffered prior correction at pH 5.5, and (ii) "rigid" buffering at pH 9.0, using organic species. Atelocollagen including co-precipitates can be obtained in the presence of one or both polysaccharides, preferably in pH domains far from the isoelectric point of scleroprotein. A critical behavior has been observed in mixtures containing gellan, due to its macromolecular dissimilarities compared with atelocollagen. In optimal binary mixtures, the coordinates of threshold points on the phase diagrams are 0.028% w/w atelocollagen/0.025% w/w hyaluronan, and 0.022% w/w atelocollagen/0.020% w/w gellan. Uni- or bi-phasic ternary systems having equilibrated ratios of co-precipitated components can be prepared starting from initial mixtures containing up to 0.032 g/dL atelocollagen, associated with, for example, 0.040 g/dL hyaluronan and 0.008 g/dL gellan, following the first pH manipulation way. PMID:23498265

Lefter, Cristina-Mihaela; Maier, Stelian Sergiu; Maier, Vasilica; Popa, Marcel; Desbrieres, Jacques

2013-01-31

319

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

320

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

321

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

322

Sexual side effects of antidepressants  

Microsoft Academic Search

Patients with depressive disorders frequently have concurrent sexual problems. The sexual dysfunction is often masked by the mood disorder, and many patients have difficulty discussing these problems openly. Thus, sexual dysfunction often is detectable only by careful inquiry. The relationship between sexual dysfunction and depressive disorders is further complicated by antidepressant therapy, which itself may cause sexual dysfunction, increasing the

Anthony J. Rothschild

2000-01-01

323

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

324

Marijuana use and sexual behavior  

Microsoft Academic Search

In several anonymous questionnaire studies of college students, marijuana use has been reported to affect sexual behavior. In general, these studies show that marijuana smoking enhances sexual pleasure and increases sexual desire. Marijuana use has also been associated with more frequent sexual activity and an increased number of sexual partners. The purpose of this study was to determine the perceived

Ronald A. Weller; James A. Halikas

1984-01-01

325

The Evolution of Sexual Pleasure  

Microsoft Academic Search

Sexual pleasure is an innate component of human sexuality. Although disdained throughout history by religious groups and variably explained by theories, philosophers, and societies, sexual pleasure permeates human experience. Traditional evolutionists explain this preoccupation via the development of sexual mating strategies and the human desire to propagate one's genes; however, here I will argue that the saturation of sexual pleasure

Felicia De la Garza-Mercer

2007-01-01

326

Depressed Mood and Sexual Functioning  

Microsoft Academic Search

Although some studies have reported substantial correlations between clinical depression and hypoactive sexual desire, thus far only a few studies have addressed the association between depressed mood and different facets of sexuality (such as sexual satisfaction, sexual activity and level of sexual problems) in close relationships. This study sought to fill this gap by examining 198 couples recruited through advertisement.

Guy Bodenmann; Thomas Ledermann

2008-01-01

327

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.

2005-01-01

328

Sexual selection without sexual dimorphism: Bateman gradients in a simultaneous hermaphrodite.  

PubMed

One of the most general patterns in sexual selection is stronger selection on mating activity in males than in females. This asymmetry is thought to result from the higher energetic cost of producing one female compared to one male gamete (anisogamy). However, most studies focused on gonochoric species with strong sexual dimorphism, in which males and females are necessarily under different selection regimes. The question remains whether anisogamy alone would suffice to produce such differences. In simultaneous hermaphrodites one can compare sexual selection on the male and female functions in the absence of sexual dimorphism. Here we quantify sexual selection in the hermaphroditic freshwater snail?Physa acuta?under laboratory conditions. We combine exhaustive behavioral records of mating activity in mating groups and molecular paternity assignment to measure the mating success and reproductive success of 120 individuals. Our results validate the prediction of stronger selection to gain mating partners in the male than in the female function. Moreover, we did not detect cross-sex effects on fitness, or correlations between male and female production of offspring over the course of our experiment. We conclude that with respect to sexual selection?P. acuta?is comparable to gonochorists, confirming that anisogamy is a sufficient explanation for the differences in sexual selection regimes between sexes. PMID:22220865

Pélissié, Benjamin; Jarne, Philippe; David, Patrice

2011-11-15

329

How reproducible is the topographical distribution of EEG amplitude?  

PubMed

If topographical EEG is to be a useful tool for localising cerebral processes, then the results of the same, or closely similar experiments, using different samples should yield similar results. Although the reliability of EEG is well established in other ways, there is little available data on the reproducibility of EEG topography across experiments. The aim of this study was to determine the reproducibility of topographical EEG by comparing the results of two independently conducted experiments. EEG was recorded during an Eyes Open baseline and a motor task condition (the Luria finger opposition task) in two independent samples of healthy subjects. EEG was recorded in 2.56-s epochs and analysed by FFT into conventional theta, alpha and beta 1 frequency bands. The EEG amplitude for each subject in each frequency range was averaged over a minimum of 60 s. Separate group averages for each sample were calculated and the resulting topographical distributions of electrical potential and current density were compared. The results indicated that the reproducibility of electrical potential in the theta and beta 1 frequency ranges was extremely poor and only approached acceptable levels in alpha. Reproducibility of current source density was poor in all frequency ranges. Although some improvement in reproducibility was obtained following spatial smoothing for alpha potential, the highest reproducibility achieved was only 0.65. Reasons for the poor reproducibility of topographical EEG and the implications of these findings are discussed. PMID:9202998

Burgess, A P; Gruzelier, J

1997-06-01

330

Sexual concerns and sexual counseling in heart failure.  

PubMed

Patients with heart failure (HF) face significant challenges in maintaining quality of life (QOL), particularly for sexual intimacy. Although recommended for all cardiac patients, it has been suggested that few HF patients receive sexual counseling. This study explored sexual counseling needs, sexual concerns, and sexual activity using a descriptive survey with HF patients (n = 45), recruited from a HF clinic or cardiology office. Most (77%) had not discussed sexual concerns with a health care professional (HCP). Sexual concerns that were rated as occurring 'occasionally/frequently' included partner overprotectiveness (63%), partner fear of sex (36%), lack of sexual interest (42%), erectile problems (74%), orgasmic difficulties (51%). Frequency of sexual intercourse before HF to present was striking, with 53% reporting no sexual activity in the last 2 months compared with 11% before diagnosis of HF. HCPs must provide sexual counseling to HF patients and partners to enhance QOL and to assist in any adaptations to sexual activity. PMID:20002338

Medina, Mary; Walker, Cynthia; Steinke, Elaine E; Wright, David W; Mosack, Victoria; Farhoud, Mohammad Hussam

2009-12-01

331

Women's Sexual Health: Talking about Your Sexual Needs  

MedlinePLUS

Sexual health Basics In-Depth Multimedia Expert Answers Resources What's New Reprints A single copy of this article ... be reprinted for personal, noncommercial use only. Women's sexual health: Talking about your sexual needs By Mayo Clinic ...

332

Chronic illness and sexuality.  

PubMed

Sex remains an important contributor to quality of life in many patients with chronic illness and their partners. The effects of chronic illness on sexuality are multifactorial and can impact on all phases of sexual response. Sexual dysfunction and dissatisfaction in chronically ill patients are underdetected and undertreated because of barriers to doctor-patient discussion about sex and lack of medical training in human sexuality. For doctors to become more motivated to broach the topic of sex, they need to recognise that people may be sexually interested even though they are old, ill or disabled. The PLISSIT model provides a graded counselling approach that allows doctors to deal with sexual issues at their own level of expertise and comfort. PMID:12924976

McInnes, Rosemary A

2003-09-01

333

Religiosity, Spirituality, Sexual Attitudes, and Sexual Behaviors Among College Students  

Microsoft Academic Search

The purpose of this study was to determine whether religiosity, spirituality, and sexual attitudes accounted for differences\\u000a in sexual behaviors among college students. The sample included 960 college students enrolled at four northeastern colleges.\\u000a Results indicated differences in sexual attitudes, religiosity, and spirituality by gender. Moreover, sexual attitudes, religiosity,\\u000a and spirituality were associated with sexual behaviors among college students. Sexual

Raffy R. Luquis; Gina M. Brelsford; Liliana Rojas-Guyler

334

Female Sexual Dysfunction  

Microsoft Academic Search

The focus of this book is men and their sexual function and dysfunction, however, many women will also develop some degree\\u000a of sexual health problems concerned with sexual desire, arousal, orgasm, and\\/or pain. The goal is to make relevant evidence-based\\u000a clinical information to help identify and treat specific biologically based pathophysiologies available to the motivated health\\u000a care professional. The prevalence

Irwin Goldstein

335

Adolescent Sexual Assault  

Microsoft Academic Search

Objective: To document the frequency and types of genital injuries in adolescent women examined acutely following a sexual assault, and determine any historical correlates of injury.Design: Retrospective chart review.Setting: Sexual Assault Response Team services at a community hospital in an urban setting.Patients: All female patients aged 14–19 yr who were referred by law enforcement for an acute sexual assault examination

Joyce A Adams; Barbara Girardin; Diana Faugno

2001-01-01

336

Sexual health and contraception.  

PubMed

Sexual health encompasses 'sexual development and reproductive health, as well as the ability to develop and maintain meaningful interpersonal relationships; appreciate one's own body; interact with both genders in respectful and appropriate ways; express affection, love and intimacy in ways consistent with one's own values'. The 2008 WHO Consensus Statement additionally noted that 'responsible adolescent intimate relationships' should be 'consensual, non-exploitative, honest, pleasurable and protected against unintended pregnancy and STDs if any type of intercourse occurs'. Young people (YP) must, therefore, be able to access sexual health information and services that meet their needs.For most YP, interest in sexual activity begins with puberty, and this is associated with increasingly sexualised behaviour, including exploration of themselves and others.Most YP find this a confusing time, and so it is important that health professionals are able to offer advice regarding the wide range of sexual health issues, including sexuality, choice of partner, contraception, risk and management of sexually transmitted infections (STI) in a confident and approachable manner. YP have never had so much choice or information available to them, and this can be confusing for them. There is good evidence that YP who get information from their parents are likely to initiate sexual activity later than their peers who access information from their friends. However, there is also evidence that some YP would prefer to get sexual health information from health professionals. It is therefore imperative that all health professionals who see YP have an awareness of sexual health issues, and know where to signpost YP should they need more specialist sexual health advice and/or treatment.Where appropriate, one-to-one sexual health advice should be provided to YP on how to prevent and get tested for STIs, and how to prevent unwanted pregnancies. Advice should also be given on all methods of reversible contraception, including long-acting reversible contraception, emergency contraception and other reproductive issues. PMID:22843336

Straw, Fiona; Porter, Charlotte

2012-07-27

337

Sexual health and contraception.  

PubMed

Sexual health encompasses 'sexual development and reproductive health, as well as the ability to develop and maintain meaningful interpersonal relationships; appreciate one's own body; interact with both genders in respectful and appropriate ways; express affection, love and intimacy in ways consistent with one's own values'. The 2008 WHO Consensus Statement additionally noted that 'responsible adolescent intimate relationships' should be 'consensual, non-exploitative, honest, pleasurable and protected against unintended pregnancy and STDs if any type of intercourse occurs'. Young people (YP) must, therefore, be able to access sexual health information and services that meet their needs. For most YP, interest in sexual activity begins with puberty, and this is associated with increasingly sexualised behaviour, including exploration of themselves and others. Most YP find this a confusing time, and so it is important that health professionals are able to offer advice regarding the wide range of sexual health issues, including sexuality, choice of partner, contraception, risk and management of sexually transmitted infections (STI) in a confident and approachable manner. YP have never had so much choice or information available to them, and this can be confusing for them. There is good evidence that YP who get information from their parents are likely to initiate sexual activity later than their peers who access information from their friends. However, there is also evidence that some YP would prefer to get sexual health information from health professionals. It is therefore imperative that all health professionals who see YP have an awareness of sexual health issues, and know where to signpost YP should they need more specialist sexual health advice and/or treatment. Where appropriate, one-to-one sexual health advice should be provided to YP on how to prevent and get tested for STIs, and how to prevent unwanted pregnancies. Advice should also be given on all methods of reversible contraception, including long-acting reversible contraception, emergency contraception and other reproductive issues. PMID:22983512

Straw, Fiona; Porter, Charlotte

2012-10-01

338

Transsexuals' Sexual Stories  

Microsoft Academic Search

When viewed through a popular cultural lens, male-to-female transsexuals' sexual biographies can appear to indicate male transvestitism,\\u000a heterosexuality, or homosexuality rather than transsexuality. How do transsexuals subvert such implications and construct\\u000a transsexual identities? Drawing on K. Plummer's (1995) approach to sexual stories, we examine how nine male-to-female transsexuals\\u000a construct their sexual pasts to accomplish what sociologists call “identity work.” Interviewees

Douglas P. Schrock; Lori L. Reid

2006-01-01

339

Parental Non-verbal Sexual Communication: Its Relationship to Sexual Behaviour and Sexual Guilt  

Microsoft Academic Search

The study explores the link between remembered non-verbal sexual communication in the home, current sexual behaviours and feelings of sexual guilt, among a sample of young British men and women. Non-verbal sexual communication encapsulates: openness about nudity in the home; the showing of affection between parents; signs of parental sexual activity and contraceptive use; and intimation of mother's menstruation. One

Hélène Joffe; Ana ClÁUdia Franca-Koh

2001-01-01

340

Sexual interest, attitudes, knowledge, and sexual history in relation to sexual behavior in the institutionalized aged  

Microsoft Academic Search

Although the idea that sexuality is a lifelong need is gaining greater research support and greater acceptability to the general public, few consider the institutionalized aged as having sexual needs or being able to benefit from sexual intimacy. The research presented here indicates that sexual activity in the institutionalized aged is related to their attitudes and behavior to ward sexuality

Charles B. White

1982-01-01

341

Sexual selection and horn allometry in the dung beetle Euoniticellus intermedius  

Microsoft Academic Search

Secondary sexual characters are often positively allometric, such that larger individuals of a species have proportionally larger traits. The sexually selected weapons found on many insect species, however, show declining allometric slopes with body size. Previous work on these curved allometric relations has focused on the role of competition for limited resources between growing body parts within pupae, but there

Joanne C. Pomfret; Robert J. Knell

2006-01-01

342

Female Condition Influences Preferences for Sexual Dimorphism in Faces of Male Humans (Homo sapiens )  

Microsoft Academic Search

In some species, female condition correlates positively with preferences for male secondary sexual traits. Women's preferences for sexually dimorphic characteristics in male faces (facial masculinity) have recently been reported to covary with self-reported attractiveness. As women's attractiveness has been proposed to signal reproductive condition, the findings in human (Homo sapiens) and other species may reflect similar processes. The current study

I. S. Penton-Voak; A. C. Little; B. C. Jones; D. M. Burt; B. P. Tiddeman; D. I. Perrett

2003-01-01

343

Quantitative Trait Loci Responsible for Variation in Sexually Dimorphic Traits in Drosophila melanogaster  

Microsoft Academic Search

To understand the mechanisms of morphological evolution and species divergence, it is essential to elucidate the genetic basis of variation in natural populations. Sexually dimorphic characters, which evolve rapidly both within and among species, present attractive models for addressing these questions. In this report, we map quantitative trait loci (QTL) responsible for variation in sexually dimorphic traits (abdomi- nal pigmentation

Artyom Kopp; Rita M. Graze; Shizhong Xu; Sean B. Carroll; Sergey V. Nuzhdin

344

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.

1996-01-01

345

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

2013-05-01

346

223. FREQUENTLY REPRODUCED VIEW OF GWMP SHOWING VARIABLE WIDTH MEDIANS ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

223. FREQUENTLY REPRODUCED VIEW OF GWMP SHOWING VARIABLE WIDTH MEDIANS WITH INDEPENDENT ALIGNMENTS FROM KEY BRIDGE LOOKING NORTHWEST, 1953. - George Washington Memorial Parkway, Along Potomac River from McLean to Mount Vernon, VA, Mount Vernon, Fairfax County, VA

347

Photographic copy of reproduced photograph dated 1942. Exterior view, west ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photographic copy of reproduced photograph dated 1942. Exterior view, west elevation. Building camouflaged during World War II. - Grand Central Air Terminal, 1310 Air Way, Glendale, Los Angeles County, CA

348

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

349

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

350

"Sexual" behavior in parthenogenetic lizards (Cnemidophorus).  

PubMed

All-female, parthenogenetic species afford a unique test of hypotheses regarding the nature and evolution of sexuality. Basic data on the behavior of parthenogens are lacking, however. We have discovered, from observations of captive Cnemidophorus uniparens, C. velox, and C. tesselatus, behavior patterns remarkably similar to the courtship and copulatory behavior of closely related sexual species. Briefly, in separately housed pairs, one lizard was repeatedly seen to mount and ride its cagemate and appose the cloacal regions. Dissection or palpation revealed that, in each instance, the courted animal was reproductively active, having ovaries containing large, preovulatory follicles, while the courting animal was either reproductively inactive or postovulatory, having ovaries containing only small, undeveloped follicles. These observations are significant for the questions they raise. For example, is this behavior a nonfunctional vestige of the species' ancestry, or is this behavior necessary for successful reproduction in the species (e.g., by priming reproductive neuroendocrine mechanisms as has been demonstrated in sexual species)? PMID:16592761

Crews, D; Fitzgerald, K T

1980-01-01

351

Mimetic butterflies support Wallace's model of sexual dimorphism  

PubMed Central

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.

Kunte, Krushnamegh

2008-01-01

352

On The Reproducibility of Seasonal Land-surface Climate  

SciTech Connect

The sensitivity of the continental seasonal climate to initial conditions is estimated from an ensemble of decadal simulations of an atmospheric general circulation model with the same specifications of radiative forcings and monthly ocean boundary conditions, but with different initial states of atmosphere and land. As measures of the ''reproducibility'' of continental climate for different initial conditions, spatio-temporal correlations are computed across paired realizations of eleven model land-surface variables in which the seasonal cycle is either included or excluded--the former case being pertinent to climate simulation, and the latter to seasonal anomaly prediction. It is found that the land-surface variables which include the seasonal cycle are impacted only marginally by changes in initial conditions; moreover, their seasonal climatologies exhibit high spatial reproducibility. In contrast, the reproducibility of a seasonal land-surface anomaly is generally low, although it is substantially higher in the Tropics; its spatial reproducibility also markedly fluctuates in tandem with warm and cold phases of the El Nino/Southern Oscillation. However, the overall degree of reproducibility depends strongly on the particular land-surface anomaly considered. It is also shown that the predictability of a land-surface anomaly implied by its reproducibility statistics is consistent with what is inferred from more conventional predictability metrics. Implications of these results for climate model intercomparison projects and for operational forecasts of seasonal continental climate also are elaborated.

Phillips, T J

2004-10-22

353

Why do most tropical animals reproduce seasonally? Testing hypotheses on an Australian snake.  

PubMed

Most species reproduce seasonally, even in the tropics where activity occurs year-round. Squamate reptiles provide ideal model organisms to clarify the ultimate (adaptive) 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 temperatures. However, although tropical reptiles are freed from this thermal constraint, most do not reproduce year-round. Seasonal reproduction in tropical reptiles might be driven by biotic factors (e.g., peak periods of predation on eggs or hatchlings, or food for hatchlings) or abiotic factors (e.g., seasonal availability of suitably moist incubation conditions). Keelback snakes (Tropidonophis mairii, Colubridae) in tropical Australia reproduce from April to November, but with a major peak in May-June. Our field studies falsify hypotheses that invoke biotic factors as explanations for this pattern: the timing of nesting does not minimize predation on eggs, nor maximize food availability or survival rates for hatchlings. Instead, our data implicate abiotic factors: female keelbacks nest most intensely soon after the cessation of monsoonal rains when soils are moist enough to sustain optimal embryogenesis (wetter nests produce larger hatchlings, that are more likely to survive) but are unlikely to become waterlogged (which is lethal to eggs). Thus, abiotic factors may favor seasonal reproduction in tropical as well as temperate-zone animals. PMID:16634304

Brown, G P; Shine, R

2006-01-01

354

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

355

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

356

Literacy and Sexual Identity.  

ERIC Educational Resources Information Center

|Calls for more attention to literacy teaching practices and teacher education that acknowledge sexual identity and orientation as key aspects of youth identity development. Discusses experience-based pedagogy and classroom interactions around sexual identities and texts. Notes the need for research and scholarship in the field of literacy and…

Moje, Elizabeth Birr; MuQaribu, Mudhillun

2003-01-01

357

Hypoactive Sexual Desire  

ERIC Educational Resources Information Center

Low-libido disorders are highly prevalent, may be extremely distressful to patients and their partners, and influence the course and prognosis of therapy. This paper focuses on this important aspect of human sexuality. Some clinical features of hypoactive sexual desire are described, and some hypotheses about etiology and prognosis are presented.…

Kaplan, Helen S.

1977-01-01

358

Taking Sexual Harassment Seriously.  

ERIC Educational Resources Information Center

Previous "School Law" columns discussed developments under Title IX (Educational Amendments of 1970), noting a trend among federal courts to apply Title IX's prohibition against sexual harassment to peer and employee-to-student sexual harassment. A recent Ninth Circuit Court of Appeals decision against the Santa Rosa City School District…

Dowling-Sendor, Benjamin

1998-01-01

359

Adolescent Sexual Timetables  

Microsoft Academic Search

Young people's age expectations for the Initiation by boys and girls of a range of sexual practices were elicited from a sample of 522 15- and 16-year-olds. As expected, there was a progression in the modal ages nominated from the least intimate (kissing) to more intimate behaviors (sexual intercourse). There were few gender differences, either for age expectations of the

Doreen A. Rosenthal; Anthony M. A. Smith

1997-01-01

360

Sequelae of sexual assault  

Microsoft Academic Search

For physicians involved in the care of female patients, the issue of sexual assault is one that presents frequently, but is often unrecognized. The prevalence among adult females of sexual abuse or frank assault is 20%. For most patients, the damage is not limited to the event and the time immediately after the assault, but it can last for years,

Carla Rodgers; Daniel Gruener

1997-01-01

361

Sexual Addiction: Diagnostic Problems  

ERIC Educational Resources Information Center

In recent years clinicians report a great deal of concern about definition, diagnostic assessment, and treatment modalities when dealing with what might be called out-of-control sexual behavior. Many terms have been used to describe the phenomenon of problematic sexual behavior. Many of these concepts overlap, some are no longer popular, and some…

Giugliano, John R.

2009-01-01

362

Sexual Abuse - The Family.  

National Technical Information Service (NTIS)

The video features a discussion of sexual abuse in children by a physician, social worker, and a psychologist. The program involves a role play by professionals of interviewing a child sexual victim and her family in an emergency room setting. The primary...

1994-01-01

363

Religiosity and Sexual Concerns  

Microsoft Academic Search

The study examined the relationships between three types of religiosity (Intrinsic, Extrinsic, and Quest) and sexual concerns in two diverse samples. Three hundred sixty-five participants were drawn from a Washington, DC area community college and a historically Black state university in North Carolina. Participants completed measures of religiosity along with the Attitudes Related to Sexual Concerns Scale (ASC; Koch &

Craig R. Cowden; Scott D. Bradshaw

2007-01-01

364

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

365

Heteronormativity hurts everyone: Experiences of young men and clinicians with sexually transmitted infection/HIV testing in British Columbia, Canada.  

PubMed

Heteronormative assumptions can negatively influence the lives of young gay and bisexual men, and recent sociological analyses have identified the negative impacts of heteronormativity on heterosexual men (e.g. 'fag discourse' targeted at heterosexual adolescents). However, insights into how heteronormative discourses may be (re)produced in clinical settings and how they contribute to health outcomes for gay, bisexual and heterosexual men are poorly understood. This analysis draws on in-depth interviews with 45 men (15-25 years old) and 25 clinicians in British Columbia, Canada, to examine how heteronormative discourses affect sexually transmitted infection testing. The sexually transmitted infection/HIV testing experience emerged as a unique situation, whereby men's (hetero)sexuality was explicitly 'interrogated'. Risk assessments discursively linked sexual identity to risk in ways that reinforced gay men as the risky 'other' and heterosexual men as the (hetero)normal and, therefore, relatively low-risk patient. This, in turn, alleviated concern for sexually transmitted infection/HIV exposure in heterosexual men by virtue of their sexual identity (rather than their sexual practices), which muted discussions around their sexual health. The clinicians also positioned sexual identities and practices as important 'clues' for determining their patients' social contexts and supports while concurrently informing particular tailored clinical communication strategies. These findings highlight how men's experiences with sexually transmitted infection/HIV testing can (re)produce heteronormative assumptions and expectations or create opportunities for more equitable gendered relations and discourses. PMID:23117592

Knight, Rod; Shoveller, Jean A; Oliffe, John L; Gilbert, Mark; Goldenberg, Shira

2012-11-01

366

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

367

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

368

[Drug facilitated sexual assault].  

PubMed

In line with the fact that there is little information regarding drug facilitated sexual assault in national medical literature, the authors aimed to prepare a review of the phenomenon based on available international references. Therefore we offered a definition of the concept of sexual assault, and rape in particular. Consent and ability for valid consent for sexual intercourse were defined as well. A review contains discussion about the basic elements of a concept of drug-facilitated sexual assault. There is also available information in regard to pharmacology of common data rape drugs, i.e. flunitrazepam, gamma-hydroxybutyrate (GHB), and ketamine. We indicate the utmost importance of prompt collecting of biological samples for toxicological screening in patients who are suspected victims of drug facilitated sexual assault. PMID:17642470

Alempijevi?, Djordje; Savi?, Slobodan; Stojanovi?, Jovan; Spasi?, Andjelka

369

Multivariate Sexual Dimorphism, Sexual Selection, and Adaptation in Greater Antillean Anolis Lizards  

Microsoft Academic Search

Sexual variation in body form is a common phenomenon in the natural world. Although most research has focused on dimorphism in size, examination of differences in shape can provide insight into ecological factors that may differ in importance to the sexes. In this study, we investigated the patterns of body shape dimorphism in 15 species of Greater Antillean Anolis lizards

Marguerite A. Butler; Jonathan B. Losos

2002-01-01

370

The Reproduction of Job Segregation by Sex: A Study of the Changing Sexual Division of Labor in the Auto and Electrical Manufacturing Industries in the 1940's.  

National Technical Information Service (NTIS)

The study seeks to account for the persistence of job segregation by sex and the process through which it is continually reproduced. The thesis is that the ideology of sexual division, which constructs male and female labor as noninterchangeable, imposes ...

R. M. Milkman

1981-01-01

371

Low species barriers in halophilic archaea and the formation of recombinant hybrids.  

PubMed

Speciation of sexually reproducing organisms requires reproductive barriers. Prokaryotes reproduce asexually but often exchange DNA by lateral gene transfer mechanisms and recombination [1], yet distinct lineages are still observed. Thus, barriers to gene flow such as geographic isolation, genetic incompatibility or a physiological inability to transfer DNA represent potential underlying mechanisms behind preferred exchange groups observed in prokaryotes [2-6]. In Bacteria, experimental evidence showed that sequence divergence impedes homologous recombination between bacterial species [7-11]. Here we study interspecies gene exchange in halophilic archaea that possess a parasexual mechanism of genetic exchange that is functional between species [12, 13]. In this process, cells fuse forming a diploid state containing the full genetic repertoire of both parental cells, which facilitates genetic exchange and recombination. Later, cells separate, occasionally resulting in hybrids of the parental strains [14]. We show high recombination frequencies between Haloferax volcanii and Haloferax mediterranei, two species that have an average nucleotide sequence identity of 86.6%. Whole genome sequencing of Haloferax interspecies hybrids revealed the exchange of chromosomal fragments ranging from 310Kb to 530Kb. These results show that recombination barriers may be more permissive in halophilic archaea than they are in bacteria. PMID:22748314

Naor, Adit; Lapierre, Pascal; Mevarech, Moshe; Papke, R Thane; Gophna, Uri

2012-06-28

372

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

373

Televised Sexual Content and Parental Mediation: Influences on Adolescent Sexuality  

Microsoft Academic Search

Little research has been conducted to examine the influence of exposure to televised sexual content on adolescent sexuality or how parental intervention may reduce negative effects of viewing such content. This study uses self-report data from 1,012 adolescents to investigate the relations among exposure to sexually suggestive programming, parental mediation strategies, and three types of adolescent sexuality outcomes: participation in

Deborah A. Fisher; Douglas L. Hill; Joel W. Grube; Melina M. Bersamin; Samantha Walker; Enid L. Gruber

2009-01-01

374

Examining Mediators of Child Sexual Abuse and Sexually Transmitted Infections  

PubMed Central

Background Interpersonal violence has increasingly been identified as a risk factor for sexually transmitted infections. Understanding the pathways between violence and sexually transmitted infections is essential to designing effective interventions. Objective To examine dissociative symptoms, alcohol use, and intimate partner physical violence and sexual coercion as mediators of child sexual abuse and lifetime sexually transmitted infection diagnosis among a sample of women. Method A convenience sample of 202 women was recruited from health care settings, with 189 complete cases for analysis. A multiple mediation model tested the proposed mediators of child sexual abuse and lifetime sexually transmitted infection diagnosis. Bootstrapping, a resampling method, was used to test for mediation. Key variables included child sexual abuse, dissociative symptoms, alcohol use, and intimate partner violence. Results Child sexual abuse was reported by 46% of the study participants (n = 93). Child sexual abuse was found to have an indirect effect on lifetime sexually transmitted infection diagnosis, with the effect occurring through dissociative symptoms (95% CI = 0.0033, 0.4714) and sexual coercion (95% CI = 0.0359, 0.7694). Alcohol use and physical violence were not found to be significant mediators. Discussion This study suggests dissociation and intimate partner sexual coercion are important mediators of child sexual abuse and sexually transmitted infection diagnosis. Therefore, interventions that consider the roles of dissociative symptoms and interpersonal violence may be effective in preventing sexually transmitted infections among women.

Sutherland, Melissa A.

2011-01-01

375

Sexual Identity Development Among Ethnic Sexual-Minority Male Youths  

Microsoft Academic Search

The current research explores how ethnicity influences sexual identity development. Among 139 sexual-minority male youths, measures of sexual identity development assessed the timing and sequencing of developmental milestones, disclosure of sexual identity to others, internalized homophobia, and same- and opposite-sex relationship histories. Findings demonstrated that participants, regardless of ethnicity, experienced most identity milestones at developmentally appropriate ages, had moderately low

Eric M. Dubé; Ritch C. Savin-Williams

1999-01-01

376

The Sexual Activity Questionnaire: A measure of women's sexual functioning  

Microsoft Academic Search

Sexual activity is an important dimension of quality of life. Therefore it is important to assess the impact that any treatment may have on sexual functioning so that patients can be warned of possible side effects and interventions offered to help ameliorate these. The Sexual Activity Questionnaire (SAQ) was developed to investigate the impact of long-term tamoxifen on the sexual

K. Thirlaway; L. Fallowfield; J. Cuzick

1996-01-01

377

Clonal Species Trichoderma parareesei sp. nov. Likely Resembles the Ancestor of the Cellulase Producer Hypocrea jecorina/T. reesei? †  

PubMed Central

We have previously reported that the prominent industrial enzyme producer Trichoderma reesei (teleomorph Hypocrea jecorina; Hypocreales, Ascomycota, Dikarya) has a genetically isolated, sympatric sister species devoid of sexual reproduction and which is constituted by the majority of anamorphic strains previously attributed to H. jecorina/T. reesei. In this paper we present the formal taxonomic description of this new species, T. parareesei, complemented by multivariate phenotype profiling and molecular evolutionary examination. A phylogenetic analysis of relatively conserved loci, such as coding fragments of the RNA polymerase B subunit II (rpb2) and GH18 chitinase (chi18-5), showed that T. parareesei is genetically invariable and likely resembles the ancestor which gave raise to H. jecorina. This and the fact that at least one mating type gene of T. parareesei has previously been found to be essentially altered compared to the sequence of H. jecorina/T. reesei indicate that divergence probably occurred due to the impaired functionality of the mating system in the hypothetical ancestor of both species. In contrast, we show that the sexually reproducing and correspondingly more polymorphic H. jecorina/T. reesei is essentially evolutionarily derived. Phenotype microarray analyses performed at seven temperature regimens support our previous speculations that T. parareesei possesses a relatively high opportunistic potential, which probably ensured the survival of this species in ancient and sustainable environment such as tropical forests.

Atanasova, Lea; Jaklitsch, Walter M.; Komon-Zelazowska, Monika; Kubicek, Christian P.; Druzhinina, Irina S.

2010-01-01

378

Sexual selection in mushroom-forming basidiomycetes  

PubMed Central

We expect that sexual selection may play an important role in the evolution of mushroom-forming basidiomycete fungi. Although these fungi do not have separate sexes, they do play female and male roles: the acceptance and the donation of a nucleus, respectively. The primary mycelium (monokaryon) of basidiomycete fungi, growing from a germinating sexual spore, is hermaphroditic, but it loses female function upon the acceptance of a second nucleus. The resulting dikaryon with two different nuclei in each cell retains a male potential as both nuclei can fertilize receptive mycelia. We tested the occurrence of sexual selection in the model species of mushroom-forming basidiomycetes, Schizophyllum commune, by pairing monokaryons with fully compatible dikaryons. In most pairings, we found a strong bias for one of the two nuclei although both were compatible with the monokaryon when paired alone. This shows that sexual selection can occur in mushroom-forming basidiomycetes. Since the winning nucleus of a dikaryon occasionally varied depending on the receiving monokaryon, we infer that sexual selection can operate through choosiness of the receiving individual (analogous to female choice). However, in other cases the same nucleus won, irrespective of the receiving monokaryon, suggesting that competition between the two nuclei of the donating mycelium (analogous to male–male competition) might also play a role.

Nieuwenhuis, Bart P. S.; Debets, Alfons J. M.; Aanen, Duur K.

2011-01-01

379

Characterization of novel genes expressed specifically in the sexual organs of the planarian Dugesia ryukyuensis.  

PubMed

The planarian Dugesia ryukyuensis reproduces both asexually (fissiparous) and sexually (oviparous) and can switch from the asexual mode to the sexual mode. By feeding with mature Bdellocephala brunnea oviparous worms, the fissiparous worms, which do not possess sexual organs, can be converted to fully sexualized worms in a process termed sexualization. As sexualization proceeds, the sexual organs are formed uniformly and five stages (stages 15) of the process have been identified histologically. In order to clarify the sexualization process, we attempted to isolate the genes expressed specifically at stage 5 by the differential display method. We isolated five genes expressed in the testis and two genes expressed in the yolk gland, which is an organ specific to sexualized worms. By BLAST search, one of the testis-specific genes was coded as testis-specific alpha-tubulin and two yolk gland-specific genes are similar to ribose-phosphate pyrophosphokinase I and F-box/SPRY-domain protein 1. Drs1, Drs2 and Drs3 were expressed in spermatocytes and spermatids from the early stage of spermatogenesis and Drs4 and Drs5 were expressed in spermatogonia, spermatocytes and spermatids. These genes are useful markers for elucidating the sexualization process. PMID:17554688

Hase, Sumitaka; Kashiwagi, Emiko; Kobayashi, Kazuya; Hoshi, Motonori; Matsumoto, Midori

2007-01-01

380

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.

2012-01-01

381

Reproducibility of dynamically represented acoustic lung images from healthy individuals  

PubMed Central

Background and aim: Acoustic lung imaging offers a unique method for visualising the lung. This study was designed to demonstrate reproducibility of acoustic lung images recorded from healthy individuals at different time points and to assess intra- and inter-rater agreement in the assessment of dynamically represented acoustic lung images. Methods: Recordings from 29 healthy volunteers were made on three separate occasions using vibration response imaging. Reproducibility was measured using quantitative, computerised assessment of vibration energy. Dynamically represented acoustic lung images were scored by six blinded raters. Results: Quantitative measurement of acoustic recordings was highly reproducible with an intraclass correlation score of 0.86 (very good agreement). Intraclass correlations for inter-rater agreement and reproducibility were 0.61 (good agreement) and 0.86 (very good agreement), respectively. There was no significant difference found between the six raters at any time point. Raters ranged from 88% to 95% in their ability to identically evaluate the different features of the same image presented to them blinded on two separate occasions. Conclusion: Acoustic lung imaging is reproducible in healthy individuals. Graphic representation of lung images can be interpreted with a high degree of accuracy by the same and by different reviewers.

Maher, T M; Gat, M; Allen, D; Devaraj, A; Wells, A U; Geddes, D M

2008-01-01

382

Reproducibility of regional brain metabolic responses to lorazepam  

SciTech Connect

Changes in regional brain glucose metabolism in response to benzodiazepine agonists have been used as indicators of benzodiazepine-GABA receptor function. The purpose of this study was to assess the reproducibility of these responses. Sixteen healthy right-handed men underwent scanning with PET and [{sup 18}F]fluorodeoxyglucose (FDG) twice: before placebo and before lorazepam (30 {mu}g/kg). The same double FDG procedure was repeated 6-8 wk later on the men to assess test-retest reproducibility. The regional absolute brain metabolic values obtained during the second evaluation were significantly lower than those obtained from the first evaluation regardless of condition (p {le} 0.001). Lorazepam significantly and consistently decreased both whole-brain metabolism and the magnitude. The regional pattern of the changes were comparable for both studies (12.3% {plus_minus} 6.9% and 13.7% {plus_minus} 7.4%). Lorazepam effects were the largest in the thalamus (22.2% {plus_minus} 8.6% and 22.4% {plus_minus} 6.9%) and occipital cortex (19% {plus_minus} 8.9% and 21.8% {plus_minus} 8.9%). Relative metabolic measures were highly reproducible both for pharmacolgic and replication condition. This study measured the test-retest reproducibility in regional brain metabolic responses, and although the global and regional metabolic values were significantly lower for the repeated evaluation, the response to lorazepam was highly reproducible. 1613 refs., 3 figs., 3 tabs.

Wang, G.J.; Volkow, N.D.; Overall, J. [Brookhaven National Lab., Upton, NY (United States)]|[SUNY, Stony Brook, NY (United States)] [and others

1996-10-01

383

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.

Hines, Melissa

2012-01-01

384

Cytological differentiation and sexual isolation between populations of Drosophila nigricruria.  

PubMed

Drosophila nigricruria has a distribution ranging from northern Mexico to Chile. It is a relatively rare species, primarily limited to cactus deserts or pine-oak associations at altitudes of 1200 to 2100 meters above sea level. The species comprises two cytological races with a zone of hybridization in the Oaxaca and Puebla regions of Mexico. Despite the zone of hybridization, gene flow for chromosome 4 genes is limited, or non-existent, between the two races. Sexual isolation tests were run using a population from the northern race, a hybrid population, and a population that is essentially southern. Sexual discrimination among these strains was on the same order of magnitude as that found between geographical populations of other species. There was no evidence to indicate that sexual isolation is any stronger between the cytological races of nigricruria than one might expect between any two geographical populations within a species. PMID:874304

Wasserman, M; Koepfer, H R

385

The herring gull complex is not a ring species.  

PubMed Central

Under what circumstances speciation in sexually reproducing animals can occur without geographical disjunction is still controversial. According to the ring-species model, a reproductive barrier may arise through 'isolation by distance' when peripheral populations of a species meet after expanding around some uninhabitable barrier. The classical example of this kind of speciation is the herring gull (Larus argentatus) complex, with a circumpolar distribution in the Northern Hemisphere. Based on mitochondrial DNA variation among 21 gull taxa, we show that members of this complex differentiated largely in allopatry following multiple vicariance and long-distance-colonization events, not primarily through isolation by distance. Reproductive isolation evolved more rapidly between some lineages than between others, irrespective of their genetic distance. Extant taxa are the result of divergent as well as reticulate evolution between two ancestral lineages originally separated in a North Atlantic refugium and a continental Eurasian refugium, respectively. Continental birds expanded along the entire north Eurasian coast and via Beringia into North America. Contrary to the ring-species model, we find no genetic evidence for a closure of the circumpolar ring through colonization of Europe by North American herring gulls. However, closure of the ring in the opposite direction may be imminent, with lesser black-backed gulls about to colonize North America.

Liebers, Dorit; de Knijff, Peter; Helbig, Andreas J.

2004-01-01

386

The evolution of sexual dimorphism in parasitic cuckoos: sexual selection or coevolution?  

PubMed Central

Sexual dimorphism is ubiquitous in animals and can result from selection pressure on one or both sexes. Sexual selection has become the predominant explanation for the evolution of sexual dimorphism, with strong selection on size-related mating success in males being the most common situation. The cuckoos (family Cuculidae) provide an exceptional case in which both sexes of many species are freed from the burden of parental care but where coevolution between parasitic cuckoos and their hosts also results in intense selection. Here, we show that size and plumage differences between the sexes in parasitic cuckoos are more likely the result of coevolution than sexual selection. While both sexes changed in size as brood parasitism evolved, we find no evidence for selection on males to become larger. Rather, our analysis indicates stronger selection on parasitic females to become smaller, resulting in a shift from dimorphism with larger females in cuckoos with parental care to dimorphism with larger males in parasitic species. In addition, the evolution of brood parasitism was associated with more cryptic plumage in both sexes, but especially in females, a result that contrasts with the strong plumage dimorphism seen in some other parasitic birds. Examination of the three independent origins of brood parasitism suggests that different parasitic cuckoo lineages followed divergent evolutionary pathways to successful brood parasitism. These results argue for the powerful role of parasite–host coevolution in shaping cuckoo life histories in general and sexual dimorphism in particular.

Kruger, O; Davies, N.B; Sorenson, M.D

2007-01-01

387

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

2008-05-11

388

Effects of emotional state on sexual desire and sexual dysfunction  

Microsoft Academic Search

The present study explored effects of emotional states on sexual desire and dysfunction. Three basic emotion dimensions, pleasure-displeasure, arousal-nonarousal, and dominance-submissiveness, served as the independent factors. Factor analysis of a sexual desire and problems questionnaire yielded a single factor with sexual desire as one pole and sexual problems as the opposite pole. The resulting “sexual desire” scale had a KR-20

Albert Mehrabian; Linda Stanton-Mohr

1985-01-01

389

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

390

The Role of Sexual Scripts in Sexual Aggression and Victimization  

Microsoft Academic Search

Two longitudinal studies examined German adolescents’ sexual scripts in relation to the normative acceptance of sexual aggression,\\u000a the behavioral enactment of risk factors, and the experience of sexual aggression\\/ victimization. Study 1 comprised a sample\\u000a of 283 10th and 11th grade high school students who completed measures of sexual scripts, normative acceptance of risk elements\\u000a associated with sexual aggression, behavioral

Barbara Krahé; Steffen Bieneck; Renate Scheinberger-Olwig

2007-01-01

391

Sexuality on the Internet: Sexual Exploration, Cybersex, and Pornography  

Microsoft Academic Search

\\u000a Sexuality as a developmental issue is present throughout the life cycle, but becomes especially salient during adolescence.\\u000a Adolescents have to adjust to their developing sexuality, in particular their increased sexual drive and interest in sex and\\u000a have the task of constructing their sexual selves. Sexual content and topics feature prominently in adolescents’ online lives\\u000a from chat rooms, to bulletin boards,

Kaveri Subrahmanyam; David Šmahel

392

Comparison of reproducing and nonreproducing starprobe strategies for galactic exploration  

NASA Astrophysics Data System (ADS)

Reproducing and nonreproducing strategies for missions of interstellar and galactic discovery are compared. Self-reproducing probes are found to be the method of choice for active exploration programs lasting more than 10,000 years, involving searches of more than 1 million target stars to distances greater than 1000 light years in the Galactic Disk, and are superior to one-shot 'Bracewell probes' for searches of more than 1000 stars to distances greater than 100 light years in the Galactic Disk. Any nonreproducing alien probes discovered in the solar system during the normal course of future SETI research would most likely have been sent by extraterrestrial civilizations located within an approximately 1000 light-year radius of the sun, whereas any self-reproducing devices similarly detected probably originated far outside this exploration sphere.

Valdes, F.; Freitas, R. A., Jr.

1980-11-01

393

The Sexual Responses of Sexual Sadists  

Microsoft Academic Search

On average, rapists show greater relative genital responses to rape stories than do nonrapists in the laboratory. It has been suggested that this robust group difference is explained by the fact that many rapists are sexually sadistic. It is not clear, however, what the critical cues underlying rapists' genital responses are, because rape stories used in previous research include a

Michael C. Seto; Martin L. Lalumière; Grant T. Harris; Meredith L. Chivers

2012-01-01

394

Sexual assault in postmenopausal women  

Microsoft Academic Search

Sexual assault is a crime of violence affecting modern American society. Victims of sexual assault tend to be women from a broad cross-section of social, economic, ethnic, and age groups. The postmenopausal woman is not immune from sexual assault and is increasingly a victim. The author presents the topic of sexual assault within the general framework of the physician's role

Susan M. Ramin

1997-01-01

395

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

Ryder, Verdene; Smith, Peggy B.

396

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

397

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

398

The evolving sexual health paradigm: transforming definitions into sexual health practices.  

PubMed

Sexual health is an evolving paradigm that integrates a positive approach to sexuality with existing public health policy and practice for reducing the burdens of sexually transmitted infections, including those due to HIV. The sexual health paradigm rests in commitment to sexual rights, sexual knowledge, sexual choice, and sexual pleasure, as well as key elements of sexuality addressed by sexual desire, sexual arousal, and sexual function, and sexual behaviors. The sexual health paradigm offers new approaches to supporting general health and well being while reducing the burdens of sexual diseases and their consequences. PMID:24088679

Fortenberry, J Dennis

2013-10-01

399

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

400

Managing female sexual dysfunction.  

PubMed

Female sexual dysfunctions (FSDs) range from short-term aggravations to major emotional disturbances adversely affecting family and workplace. This review highlights diagnosis and management of the four most widely diagnosed FSDs. It initially focuses on hypoactive sexual desire disorder (HSDD) as a driving force at the heart of all other FSDs; nothing happens without sexual desire. Successful resolution of HSDD frequently facilitates resolution of other disorders. Central to understanding HSDD is the impact of aging female sexual endocrinology and its effect on both prevalence and expression patterns of FSD. Advances in this field have enabled introduction of some the most effective treatments yet described for HSDD. Sexual arousal disorder, though commonly affected by the same factors as HSDD, is heavily associated with psychotropic drugs and mood elevators. Orgasmic disorder is frequently the downstream result of other sexual dysfunctions, particularly HSDD, or the result of a major psychosexual trauma. Successful management of the underlying disorder often resolves orgasmic disorder. Sexual pain disorder is frequently the result of a gynecologic disorder, such as endometriosis, that can be substantially managed through successful treatment of that disorder. This article ends with the article's most important note: how to initiate the conversation. PMID:24074537

Buster, John E

2013-10-01

401

Allometry, bilateral asymmetry and sexual differences in the vocal tract of common eiders Somateria mollissima and king eiders S. spectabilis  

Microsoft Academic Search

Intraspecific sexual differences, high variation, and positive allometry of sexually-selected external display structures are common. Many sexually-selected anatomical specializations occur in the avian vocal tract but intraspecific variation and allometry have been investigated little. The tracheal bulla bulla syringealis occurs in males of most duck species. We quantified variation and size-scaling of the bulla, plus sexual differences in size of

Edward H. Miller; Joni Williams; Sarah E. Jamieson; H. Grant Gilchrist; Mark L. Mallory

2007-01-01

402

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.

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

2010-01-01

403

Derivative reproducing properties for kernel methods in learning theory  

NASA Astrophysics Data System (ADS)

The regularity of functions from reproducing kernel Hilbert spaces (RKHSs) is studied in the setting of learning theory. We provide a reproducing property for partial derivatives up to order s when the Mercer kernel is C2s. For such a kernel on a general domain we show that the RKHS can be embedded into the function space Cs. These observations yield a representer theorem for regularized learning algorithms involving data for function values and gradients. Examples of Hermite learning and semi-supervised learning penalized by gradients on data are considered.

Zhou, Ding-Xuan

2008-10-01

404

Evolutionarily stable strategies of age-dependent sexual advertisement  

Microsoft Academic Search

In various models of sexual selection mediated by the viability indicator (“good genes”) mechanism, a sexually selected trait\\u000a will truly reflect male quality if its expression is costly for the male. However, in long-lived species, the expression of\\u000a a trait often increases with age while the genotype of the male remains unchanged. This fact may obscure the indicator mechanism.\\u000a Hitherto,

Hanna Kokko

1997-01-01

405

Sexual rights and disability.  

PubMed

This paper argues against Appel's recent proposal-in this journal-that there is a fundamental human right to sexual pleasure, and that therefore the sexual pleasure of severely disabled people should be publicly funded-by thereby partially legalising prostitution. An alternative is proposed that does not need to pose a new positive human right; does not need public funding; does not need the legalisation of prostitution; and that would offer a better experience to the severely disabled: charitable non-profit organisations whose members would voluntarily and freely provide sexual pleasure to the severely disabled. PMID:21059634

Di Nucci, Ezio

2010-11-08

406

AIDS and human sexuality.  

PubMed

The sexual behaviours placing an individual at risk for HIV infection are those also placing him/her at risk for gonorrhoea, syphilis, hepatitis B, chlamydia and unplanned pregnancy. This article proposes that approaches to HIV prevention must be included within a broad context of human sexuality. To address disease prevention in the absence of including people's relationships, social, behavioural and emotional needs is futile. Compartmentalization, denial of risk by various populations, and societal barriers are all factors to be overcome in the fight against HIV transmission. Specific strategies involved in a comprehensive approach are outlined under the categories of predisposing, enabling and reinforcing factors contributing to healthy sexual behaviour. PMID:8481861

Smith, L L; Lathrop, L M

407

Objectification Theory and Sexual Health among Women  

Microsoft Academic Search

This study used objectification theory as a framework through which to explore the effect of interpersonal objectification, self-objectification, and indicators of selfobjectification (body shame, general surveillance, and surveillance during sexual activity) on women’s sexual health, including sexual subjectivity (sexual body esteem, sexual selfreflection, and entitlement and efficacy in attaining pleasure), sexual functioning, and risky sexual behaviors. It was hypothesized that

Kara Lustig

2012-01-01

408

Sexual conflict and the maintenance of multivariate genetic variation.  

PubMed

Mate choice should erode additive genetic variation in sexual displays, yet these traits often harbor substantial genetic variation. Nevertheless, recent developments in quantitative genetics have suggested that multivariate genetic variation in the combinations of traits under selection may still be depleted. Accordingly, the erosion and maintenance of variation may only be detectable by studying whole suites of traits. One potential process favoring the maintenance of genetic variance in multiple trait combinations is the modification of sexual selection via sexually antagonistic interactions between males and females. Here we consider how interlocus sexual conflict can shape the genetic architecture of male sexual traits in the cricket, Teleogryllus commodus. In this species, the ability of each sex to manipulate insemination success significantly alters the selection acting on male courtship call properties. Using a quantitative genetic breeding design we estimated the additive genetic variation in these traits and then predicted the change in variation due to previously documented patterns of sexual selection. Our results indicate that female choice should indeed deplete multivariate genetic variance, but that sexual conflict over insemination success may oppose this loss of variance. We suggest that changes in the direction of selection due to sexually antagonistic interactions will be an important and potentially widespread factor in maintaining multivariate genetic variation. PMID:20050914

Hall, Matthew D; Lailvaux, Simon P; Blows, Mark W; Brooks, Robert C

2009-12-28

409

Evidence for no sexual isolation between Drosophila albomicans and D. nasuta  

PubMed Central

Sexual isolation, the reduced tendency to mate, is one of the reproductive barriers that prevent gene flow between different species. Various species-specific signals during courtship contribute to sexual isolation between species. Drosophila albomicans and D. nasuta are closely related species of the nasuta subgroup within the Drosophila immigrans group and are distributed in allopatry. We analyzed mating behavior and courtship as well as cuticular hydrocarbon profiles within and between species. Here, we report that these two species randomly mated with each other. We did not observe any sexual isolation between species or between strains within species by multiple-choice tests. Significant difference in the courtship index was detected between these two species, but males and females of both species showed no discrimination against heterospecific partners. Significant quantitative variations in cuticular hydrocarbons between these two species were also found, but the cuticular hydrocarbons appear to play a negligible role in both courtship and sexual isolation between these two species. In contrast to the evident postzygotic isolation, the lack of sexual isolation between these two species suggests that the evolution of premating isolation may lag behind that of the intergenomic incompatibility, which might be driven by intragenomic conflicts.

Kim, Yong-Kyu; Phillips, Dennis R; Tao, Yun

2013-01-01

410

Informal Sexuality Education in Schools  

Microsoft Academic Search

Sexuality education occurs both formally and informally in the public school system. This study sought to assess sexuality education in Indiana public schools-the classroom curricula as well as students' sexuality-related questions. Data were collected from teachers, nurses, and counselors (N = 399) pertaining to the inclusion of specific topics in sexuality education courses; sexuality-related questions received from students; and reported

Amanda Tanner; Michael Reece; Laurie Legocki; Maresa Murray

2007-01-01

411

Sexual Dysfunction in Parkinson's Disease  

Microsoft Academic Search

Sexual dysfunction is common in Parkinson's disease (PD). We investigated the premorbid and present sexual functioning of 75 people with PD (32 women and 43 men). Women reported difficulties with arousal (87.5%), with reaching orgasm (75.0%), with low sexual desire (46.9%), and wih sexual dissatisfaction (37.5%). Men reported erectile dysfunction (68.4%), sexual dissatisfaction (65.1%), premature ejaculation (40.6%), and difficulties reaching

GILA BRONNER; VLADIMIR ROYTER; AMOS D. KORCZYN; NIR GILADI

2004-01-01

412

Lesbian and bisexual women's human rights, sexual rights and sexual citizenship: negotiating sexual health in England  

Microsoft Academic Search

Lesbian and bisexual women's sexual health is neglected in much Government policy and practice in England and Wales. This paper examines lesbian and bisexual women's negotiation of sexual health, drawing on findings from a small research project. Themes explored include invisibility and lack of information, influences on decision-making and sexual activities and experiences of services and barriers to sexual healthcare.

Eleanor Formby

2011-01-01

413

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.

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

2011-01-01

414

Prenatal Programming of Sexual Partner Preference  

PubMed Central

In our laboratory the domestic ram is used as an experimental model to study the early programming of neural mechanisms underlying same-sex partner preference. This interest developed from the observation that ?8% of domestic rams are sexually attracted to other rams (male-oriented) in contrast to the majority of rams that are attracted to oestrous ewes (female-oriented). One prominent feature of sexual differentiation in many species is the presence of a sexually dimorphic nucleus (SDN) in the preoptic/anterior hypothalamus that is larger in males than in females. Lesion studies in rats and ferrets implicate the SDN in the expression of sexual preferences. We discovered an ovine SDN (oSDN) in the preoptic/anterior hypothalamus that is smaller in male- than in female-oriented rams and similar in size to the oSDN of ewes. Neurons of the oSDN show abundant aromatase expression that is also reduced in male-oriented compared to female-oriented rams. This observation suggests that sexual partner preferences are neurologically hard-wired and could be influenced by hormones. Aromatase-containing neurons constitute a nascent oSDN as early as d 60 of gestation, which becomes sexually dimorphic by d 135 of gestation when it is 2 times larger in males than in females. Exposure of fetal female lambs to exogenous testosterone from d 30 to 90 of gestation resulted in a masculinised oSDN. These data demonstrate that the oSDN develops prenatally and may influence adult sexual preferences. Surprisingly, inhibition of aromatase activity in the brain of ram fetuses during the critical period did not interfere with defeminisation of adult sexual partner preference or oSDN volume. These results fail to support an essential role for neural aromatase in the sexual differentiation of sheep brain and behaviour. Thus, we propose that oSDN morphology and male-typical partner preferences may instead be programmed through an androgen receptor mechanism not involving aromatisation.

Roselli, C.E.; Stormshak, F.

2009-01-01

415

Sex and the singular DM domain: insights into sexual regulation, evolution and plasticity  

PubMed Central

Most animals reproduce sexually, but the genetic and molecular mechanisms that determine the eventual sex of each embryo vary remarkably. DM domain genes, which are related to the insect gene doublesex, are integral to sexual development and its evolution in many metazoans. Recent studies of DM domain genes reveal mechanisms by which new sexual dimorphisms have evolved in invertebrates and show that one gene, Dmrt1, was central to multiple evolutionary transitions between sex-determining mechanisms in vertebrates. In addition, Dmrt1 coordinates a surprising array of distinct cell fate decisions in the mammalian gonad and even guards against transdifferentiation of male cells into female cells in the adult testis.

Matson, Clinton K.; Zarkower, David

2013-01-01

416

New Insights into Placozoan Sexual Reproduction and Development  

PubMed Central

Unraveling animal life cycles and embryonic development is basic to understanding animal biology and often sheds light on phylogenetic relationships. A key group for understanding the evolution of the Metazoa is the early branching phylum Placozoa, which has attracted rapidly increasing attention. Despite over a hundred years of placozoan research the life cycle of this enigmatic phylum remains unknown. Placozoa are a unique model system for which the nuclear genome was published before the basic biology (i.e. life cycle and development) has been unraveled. Four organismal studies have reported the development of oocytes and one genetic study has nourished the hypothesis of sexual reproduction in natural populations at least in the past. Here we report new observations on sexual reproduction and embryonic development in the Placozoa and support the hypothesis of current sexual reproduction. The regular observation of oocytes and expressed sperm markers provide support that placozoans reproduce sexually in the field. Using whole genome and EST sequences and additional cDNA cloning we identified five conserved sperm markers, characteristic for different stages in spermatogenesis. We also report details on the embryonic development up to a 128-cell stage and new ultrastructural features occurring during early development. These results suggest that sperm and oocyte generation and maturation occur in different placozoans and that clonal lineages reproduce bisexually in addition to the standard mode of vegetative reproduction. The sum of observations is best congruent with the hypothesis of a simple life cycle with an alternation of reproductive modes between bisexual and vegetative reproduction.

Eitel, Michael; Guidi, Loretta; Hadrys, Heike; Balsamo, Maria; Schierwater, Bernd

2011-01-01

417

The Legal Framework for Reproducible Scientific Research: Licensing and Copyright  

Microsoft Academic Search

As computational researchers increasingly make their results available in a reproducible way, and often outside the traditional journal publishing mechanism, questions naturally arise with regard to copyright, subsequent use and citation, and ownership rights in general. The growing number of scientists who release their research publicly face a gap in the current licensing and copyright structure, particularly on the Internet.

Victoria Stodden

2009-01-01

418

How reproducible is the topographical distribution of EEG amplitude?  

Microsoft Academic Search

If topographical EEG is to be a useful tool for localising cerebral processes, then the results of the same, or closely similar experiments, using different samples should yield similar results. Although the reliability of EEG is well established in other ways, there is little available data on the reproducibility of EEG topography across experiments. The aim of this study was

A Burgess; J Gruzelier

1997-01-01

419

KRASH: Reproducible CPU load generation on many-core machines  

Microsoft Academic Search

In this article we present KRASH, a tool for reproducible generation of system-level CPU load. This tool is intended for use in shared memory machines equipped with multiple CPU cores which are usually exploited concurrently by several users. The objective of KRASH is to enable parallel application developers to validate their resources use strategies on a partially loaded machine by

Swann Perarnau; Guillaume Huard

2010-01-01

420

ISSUES ON REPRODUCIBILITY\\/RELIABILITY OF MAGNETIC NDE METHODS  

Microsoft Academic Search

INTRODUCTIONOne of the critical elements related to the practicality of any NDE technique is itsreproducibility under nominally the same inspection conditions. The results of certain testmethodologies, however, are not always repeatable and understanding the origin of the irreproducibilityis often as critical as obtaining reproducible results. One example is the characterizationof residual stress in structural ferromagnets using the magnetoacoustic (MAC)method [1].

M. Namkung; J. P. Fulton; B. Wincheski; S. Nath

421

Reproducibility of Retinal Mapping Using Optical Coherence Tomography  

Microsoft Academic Search

Objective: To assess the reproducibility of retinal thick- ness measurement using commercially available map- ping software of optical coherence tomography (OCT). Methods: Six radial scans, 6 mm long and centered on the fixation point, were performed on 10 eyes of 10 healthy volunteers and 10 eyes of 10 diabetic patients with clini- cally significant macular edema. Retinal thickness was measured

Pascale Massin; Eric Vicaut; Belkacem Haouchine; Ali Erginay; Michel Paques; Alain Gaudric

2001-01-01

422

Reproducibility and comparison of responses to inhaled histamine and methacholine  

Microsoft Academic Search

The efficiency of a standardised inhalation test procedure was studied by examining the reproducibility of responses to histamine and methacholine. In addition, the responses to the two agents were compared. Each set of duplicate tests was carried out on a separate day within one week, and all factors known or presumed to influence responses were carefully controlled. The results were

E F Juniper; P A Frith; C Dunnett; D W Cockcroft; F E Hargreave

1978-01-01

423

Latin America Today: An Atlas of Reproducible Pages. Revised Edition.  

ERIC Educational Resources Information Center

|This document contains reproducible maps, charts and graphs of Latin America for use by teachers and students. The maps are divided into five categories (1) the land; (2) peoples, countries, cities, and governments; (3) the national economies, product, trade, agriculture, and resources; (4) energy, education, employment, illicit drugs, consumer…

World Eagle, Inc., Wellesley, MA.

424

Ethical reproducibility: towards transparent reporting in biomedical research.  

PubMed

Optimism about biomedicine is challenged by the increasingly complex ethical, legal and social issues it raises. Reporting of scientific methods is no longer sufficient to address the complex relationship between science and society. To promote 'ethical reproducibility', we call for transparent reporting of research ethics methods used in biomedical research. PMID:23985730

Anderson, James A; Eijkholt, Marleen; Illes, Judy

2013-09-01

425

Multiresolution reproducing kernel particle method for computational fluid dynamics  

Microsoft Academic Search

Multiresolution analysis based on the reproducing kernel particle method (RKPM) is developed for computational fluid dynamics. An algorithm incorporating multiple-scale adaptive refinement is introduced. The concept of using a wavelet solution as an error indicator is also presented. A few representative numerical examples are solved to illustrate the performance of this new meshless method. Results show that the RKPM is

Sukky Jun; Dirk Thomas Sihling; Yijung Chen; Wei Hao

1997-01-01

426

Reproducibility of an Italian food frequency questionnaire for cancer studies  

Microsoft Academic Search

The reproducibility of measures of the intake of total energy and 27 selected nutrients from a quantitative food frequency questionnaire (FFQ) used in a case-control study on cancer of the breast, ovary, and digestive tract was evaluated. The results of two FFQ administrations at an interval of 3 to 10 months (median = 5.4 months) to 452 volunteers (144 males

Silvia Franceschi; Fabio Barbone; Eva Negri; Adriano Decarli; Monica Ferraroni; Rosa Filiberti; Attilio Giacosa; Patrizia Gnagnarella; Oriana Nanni; Simonetta Salvini; Carlo La Vecchia

1995-01-01

427

The United States Today: An Atlas of Reproducible Pages.  

ERIC Educational Resources Information Center

Black and white maps, graphs and tables that may be reproduced are presented in this volume focusing on the United States. Some of the features of the United States depicted are: size, population, agriculture and resources, manufactures, trade, citizenship, employment, income, poverty, the federal budget, energy, health, education, crime, and the…

World Eagle, Inc., Wellesley, MA.

428

Latin America Today: An Atlas of Reproducible Pages. Revised Edition.  

ERIC Educational Resources Information Center

This document contains reproducible maps, charts and graphs of Latin America for use by teachers and students. The maps are divided into five categories (1) the land; (2) peoples, countries, cities, and governments; (3) the national economies, product, trade, agriculture, and resources; (4) energy, education, employment, illicit drugs, consumer…

World Eagle, Inc., Wellesley, MA.

429

Reproducing Reflection Properties of Natural Textures onto Real Object Surfaces  

Microsoft Academic Search

Synthetic decorative materials such as synthetic leather and printed wood grain are widely used in our everyday life, but we often notice that they are imitations because they lack richness of the appearance. One of the differences between the appearances of natural materials and synthetic ones is the complicated variance of reflection, but imitations have no means for reproducing the

Naoki Kawai

430

Wave propagation software, computational science, and reproducible research  

Microsoft Academic Search

Wave propagation algorithms are a class of high-resolution finite volume methods for solving hyperbolic partial differential equations arising in diverse applications. The development and use of the clawpack software implementing these methods serves as a case study for a more general discussion of mathematical aspects of software development and the need for more reproducibility in computational research. Sample applications discussed

Randall J. LeVeque

2006-01-01

431

Reproducibility of Tactile Assessments for Children with Unilateral Cerebral Palsy  

ERIC Educational Resources Information Center

|A systematic review identified tactile assessments used in children with cerebral palsy (CP), but their reproducibility is unknown. Sixteen children with unilateral CP and 31 typically developing children (TDC) were assessed 2-4 weeks apart. Test-retest percent agreements within one point for children with unilateral CP (and TDC) were…

Auld, Megan Louise; Ware, Robert S.; Boyd, Roslyn Nancy; Moseley, G. Lorimer; Johnston, Leanne Marie

2012-01-01

432

Technique for increasing reproducibility in EPR dosimetry of tooth enamel  

Microsoft Academic Search

Variations in several electron paramagnetic resonance (EPR) spectral parameters of importance in retrospective dosimetry of tooth enamel were measured using instrumentation and methodologies designed to maximize measurement reproducibility. Measurements were made using accessory EPR equipment that can be readily constructed with little more than a variable power supply, a geared down motor and some high-purity CaO. Spectroscopic precision is considerably

R. B. Hayes; E. H. Haskell; A. A. Romanyukha; G. H. Kenner

1998-01-01

433

Men and Sexual Trauma  

MedlinePLUS

... to Women - Return from War - PTSD and Communities - PTSD Research - Mobile Apps - Páginas en Español - Videos - Web Links PROFESSIONAL ABOUT US PTSD Awareness Month Men and Sexual Trauma Men and ...

434

Rape (sexual assault) - overview  

MedlinePLUS

Sex and rape; Date rape; Sexual assault ... Rape may occur between members of the same sex. This is more common in places such as prisons, military settings, and single-sex schools. People with physical or mental disabilities or ...

435

The Sexual Assault Examination  

PubMed Central

The sexual assault examination poses many problems for physicians. They must deal not only with the patient's physical and emotional trauma, but also collect forensic evidence, and provide proper treatment and follow-up. Patient management has been simplified and improved in Ontario by a standardized sexual assault examination kit. It has been used at McMaster University's Regional Sexual Assault Centre since its establishment in 1979. The first step in managing victims is ensuring their wellbeing, and treating them sympathetically. The kit provides information on consent, taking the sexual assault history, recording the patient's emotional status, and treatment guidelines. It also contains equipment and instructions on collecting clothing and body evidence, and on the genital and anal examination. The collection of good forensic evidence can decrease the need for doctors and nurses to testify in court. ImagesFig. 1

Hargot, L. A.

1985-01-01

436

Sexuality After Breast Cancer  

MedlinePLUS

... breast cancer treatment Emotional aspects of breast cancer Body image after breast cancer treatment Sexuality after breast cancer ... treatment for breast cancer stops working Previous Topic Body image after breast cancer treatment Next Topic Pregnancy after ...

437

Female Sexual Dysfunction  

MedlinePLUS

... after removal of the ovaries* Psychological and Emotional Causes Mental distress: stress, anxiety, depression, eating disorders, past sexual abuse, fear of unwanted pregnancy Relationship issues: boredom, anger, power struggles, ...

438

Female sexual dysfunction  

MedlinePLUS

... women was thought to be largely due to psychological problems. Recent research is beginning to uncover many ... women. While many sexual problems have an underlying psychological component, possible physical causes must be ruled out ...

439

Understanding Sexual Violence  

MedlinePLUS

... and behaviors in their kids. • Creating policies at work, at school, and in other places that address sexual harassment. • Developing mass media (e.g., radio, TV, magazines, newspapers) messages that promote norms, or ...

440

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.

441

Teen Sexual Health  

MedlinePLUS

... to have sex. If you choose to have sex, however, latex condoms are the best protection against sexually transmitted diseases (STDs). Condoms are also a form of birth control to help prevent pregnancy.

442

Sexuality and Dementia  

MedlinePLUS

Home > Newsletters > Connections newsletter - Archives > Spring 2001 > Sexuality and Dementia E-mail to a Friend Printable Version ©Family Caregiver Alliance Coping with Changes in Your Intimate Relationship How has your relationship ...

443

Factors Mediating the Effects of Childhood Sexual Abuse on Risky Sexual Behavior Among College Women  

Microsoft Academic Search

We surveyed 157 college women regarding sexual abuse, age at first intercourse, reactions to first intercourse, sexual attitudes, and sexual risk behavior outcomes to clarify the relationship between early sexual experiences and risky sexual behavior. Women who had been sexually abused in childhood reported greater numbers of lifetime sexual partners. This relationship was partially explained by adolescent\\/adult sexual abuse, age

Mary E. Randolph; Katie E. Mosack

2006-01-01

444

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

2013-08-13

445

The implications of sexual narcissism for sexual and marital satisfaction.  

PubMed

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

2013-01-08

446

Personality and Sexual Relations  

Microsoft Academic Search

This investigation examined the links between self-monitoring propensities and orientations toward sexual relations. A factor analysis of behavioral and attitudinal survey data revealed that high self-monitoring individuals tend to establish an unrestricted orientation toward sexual relations (such that they may engage in sex with others to whom they are not necessarily psychologically close), whereas low self-monitoring individuals tend to establish

Mark Snyder; Jeffry A. Simpson; Steve Gangestad

1986-01-01

447

Gender and Sexual Risk  

Microsoft Academic Search

Two hypotheses are evaluated in thisinvestigation of gender differences in the attitudinaland behavioral correlates of sexual risk. The“difference in magnitude” hypothesispredicts that the same factors are implicated for women and men butdifferences occur in the strength of correlates.Alternatively, women may engage in sexual risk fordifferent reasons than do men, leading to a“difference in pattern” hypothesis. We compared these possibilitieswith a

Nancy J. Bell; Keri K. O'Neal; Du Feng; Carol J. Schoenrock

1999-01-01

448

[Acquiring a sexual identity].  

PubMed

Progressive acquisition from childhood onwards to adulthood of a procreative and psycho-emotional sexual identity is presented in all its bio-psycho-social complexity. Gender identity disorders (GDI) and the different sexual orientations (hetero-, homo- or bisexual) are included with their possible etiologies. Different medico-psycho-social programs and projects are presented targeting persons having difficulties in this developmental process of their identity. PMID:23547360

Kjellberg, G

2013-03-20

449

Melanocortins in sexual function  

Microsoft Academic Search

The melanocortin system is involved in mainly regulatory activity in many physiologic systems. Of the five subtypes of receptors,\\u000a the MC4R appears most associated with sexual modulation. The MC4R subtype is found in the central nervous system in sites\\u000a known to be associated with sexual function, and preclinical evidence points to the importance of regions of the hypothalamus.\\u000a There is

Jeremy P. W. Heaton; Alvaro Morales; Michael A. Adams

2004-01-01

450

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

451

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

Microsoft Academic Search

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 were administered the Sexual Experiences Inventory, Miller-Fisk

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

2009-01-01

452

Reproducibility of dual-photon absorptiometry using a clinical phantom  

SciTech Connect

The use of dual-photon absorptiometry (DPA) bone mineral density (BMD) to monitor bone for diagnosis and monitoring therapy of osteoporosis has been established. The objective of this study is to determine the reproducibility of DPA measurements. A phantom was constructed using a section of human boney pelvis and lumbo-sacral spine. Provisions were made to mimic changes in patient girth. To evaluate the DPA reproducibility within a single day, 12 consecutive studies were performed on the phantom using standard acquisition and processing procedures. The mean BMD +-1 SD in gms/cm/sup 2/ (BMD-bar)of lumbar vertebrae 2-4 was 0.771 +- 0.007 with a 0.97% coefficient of variation (1SD) (CV). This evaluation was repeated 7 times over the next 4 months with the performance of 3 to 6 studies each time, the maximum CV found was 1.93. In order to evaluate the DPA reproducibility with time, phantom studies were performed over a 7 month period which included a 153-Gd source change. The BMD-bar was 0.770 +- 0.017 with a 2.15CV. DPA reproducibility with patient girth changes was evaluated by performing the phantom studies at water depths of 12.5, 17.0 and 20.0cm. Five studies of each were performed using standard acquisition and processing procedures. The BMD-bar was 0.779 +- 0.012 with a 1.151CV. based on these results, BMD measurements by DPA are reproducible within 2%. This reliability is maintained for studies performed over extended period of time and are independent of changes in patient girth.

DaCosta, M.; DeLaney, M.; Goldsmith, S.J.

1985-05-01

453

Reproducibility of multifocal VEP latency using different stimulus presentations.  

PubMed

The aims of the article were to study the reproducibility of latency of multifocal visual evoked potential (mfVEP) recorded using different stimulus presentations and to identify the peak with least variability. Ten normal subjects, aged between 22 and 52 years (mean age 32 ± 8.37 years), participated in the study. All subjects underwent mfVEP testing with pattern reversal and pattern pulse stimulus presentations. The stimulus subtends 26° from fixation and includes 24 segments. Only the vertical channel was recorded on all subjects. Testing was repeated after 1-2 weeks. Only the right eye of all subjects was analysed. Segments with low signal-to-noise ratios (SNR < 1.5) were excluded from analysis. The latencies were analysed to confirm values from the same peak for the two tests. The latency values were then analysed for the start of the response, the first peak and the second peak. The waveforms were reproducible throughout the field. Reproducibility of latency at the "start of the response" was significantly lesser than the first and the second peaks studied, while the reproducibility of latency at the first peak was not statistically different from the second peak for either pattern reversal or pattern pulse stimulation. The latency values were not different between the first and the second sessions for either pattern reversal or pattern pulse stimulation for any of the peaks. The pattern reversal stimulus presentation produced less variability in latency. The first peak is the most reproducible among the three measures in both the stimulus presentation. PMID:22669286

Sriram, Prema; Klistorner, Alexander; Arvind, Hemamalini; Graham, Stuart L

2012-06-06

454

[Cardiovascular disease and sexuality].  

PubMed

Sexual activity corresponds to light to moderate physical exercise and entails no significant risk to the majority of patients with cardiovascular disease. In patients suffering from severe angina or chronic heart failure, however, sexual activity might trigger coital angina or cardiac decompensation necessitating hospitalization. Nevertheless, even for patients with coronary artery disease the absolute risk of having a heart attack or fatal event during sexual activity is extremely low. Due to systemic atherosclerosis and concomitant endothelial dysfunction the prevalence of sexual dysfunction is higher in patients with cardiovascular disease as compared to the general population. PDE-5 inhibitors can be safely used by many patients suffering from both, cardiovascular disease and sexual dysfunction as long as no concomitant medication with nitrates exists. The concomitant use of PDE-5 inhibitors and nitrates is strictly contraindicated because of the risk of life-threatening hypotension. It is therefore of utmost importance to ask patients presenting with coital angina about PDE-5 inhibitor intake before the administration of nitrate-based anti-ischemic therapies. The recommendations of the Princeton Consensus Conference provide a useful framework for risk stratification and counseling of patients with cardiovascular disease regarding sexual activity. PMID:20235042

Pfister, Otmar

2010-03-01

455

A fungal sexual revolution: Aspergillus and Penicillium show the way.  

PubMed

Fungi have some of the most diverse sex lives in nature, ranging from self-fertility to obligate outcrossing systems with several thousand different sexes, although at least 20% of fungal species have no known sexual stage. However, recent evidence suggests that many supposed 'asexual' species do indeed have the potential to undergo sexual reproduction. Using experimental and genomic findings from Aspergillus and Penicillium species as examples, it is argued that evidence such as the presence and expression of apparently functional sex-related genes, the distribution of mating-type genes, detection of recombination from population genetic analyses, and the discovery of extant sexual cycles reveal an on-going revolution in the understanding of fungal asexuality. PMID:22032932

Dyer, Paul S; O'Gorman, Céline M

2011-10-25

456

Sexual selection on brain size in shorebirds (Charadriiformes).  

PubMed

Natural selection is considered a major force shaping brain size evolution in vertebrates, whereas the influence of sexual selection remains controversial. On one hand, sexual selection could promote brain enlargement by enhancing cognitive skills needed to compete for mates. On the other hand, sexual selection could favour brain size reduction due to trade-offs between investing in brain tissue and in sexually selected traits. These opposed predictions are mirrored in contradictory relationships between sexual selection proxies and brain size relative to body size. Here, we report a phylogenetic comparative analysis that highlights potential flaws in interpreting relative brain size-mating system associations as effects of sexual selection on brain size in shorebirds (Charadriiformes), a taxonomic group with an outstanding diversity in breeding systems. Considering many ecological effects, relative brain size was not significantly correlated with testis size. In polyandrous species, however, relative brain sizes of males and females were smaller than in monogamous species, and females had smaller brain size than males. Although these findings are consistent with sexual selection reducing brain size, they could also be due to females deserting parental care, which is a common feature of polyandrous species. Furthermore, our analyses suggested that body size evolved faster than brain size, and thus the evolution of body size may be confounding the effect of the mating system on relative brain size. The brain size-mating system association in shorebirds is thus not only due to sexual selection on brain size but rather, to body size evolution and other multiple simultaneous effects. PMID:23489329

García-Peña, G E; Sol, D; Iwaniuk, A N; Székely, T

2013-03-13

457

Body size dimorphism and sexual segregation in polygynous ungulates: an experimental test with Soay sheep  

Microsoft Academic Search

Sexual segregation in Soay sheep (Ovis aries) was investigated using an experimental approach in order to test the sexual dimorphism-body size hypothesis. Two corollaries\\u000a of the sexual dimorphism-body size hypothesis were tested: (1) in dimorphic species males, the larger sex, have relatively\\u000a smaller bite sizes on short swards because of the scaling of incisor arcade with body weight, and (2)

F. J. Pérez-Barbería; I. J. Gordon

1999-01-01

458

Composting in small laboratory pilots: Performance and reproducibility  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer We design an innovative small-scale composting device including six 4-l reactors. Black-Right-Pointing-Pointer We investigate the performance and reproducibility of composting on a small scale. Black-Right-Pointing-Pointer Thermophilic conditions are established by self-heating in all replicates. Black-Right-Pointing-Pointer Biochemical transformations, organic matter losses and stabilisation are realistic. Black-Right-Pointing-Pointer The organic matter evolution exhibits good reproducibility for all six replicates. - Abstract: Small-scale reactors (<10 l) have been employed in composting research, but few attempts have assessed the performance of composting considering the transformations of organic matter. Moreover, composting at small scales is often performed by imposing a fixed temperature, thus creating artificial conditions, and the reproducibility of composting has rarely been reported. The objectives of this study are to design an innovative small-scale composting device safeguarding self-heating to drive the composting process and to assess the performance and reproducibility of composting in small-scale pilots. The experimental setup included six 4-l reactors used for composting a mixture of sewage sludge and green wastes. The performance of the process was assessed by monitoring the temperature, O{sub 2} consumption and CO{sub 2} emissions, and characterising the biochemical evolution of organic matter. A good reproducibility was found for the six replicates with coefficients of variation for all parameters generally lower than 19%. An intense self-heating ensured the existence of a spontaneous thermophilic phase in all reactors. The average loss of total organic matter (TOM) was 46% of the initial content. Compared to the initial mixture, the hot water soluble fraction decreased by 62%, the hemicellulose-like fraction by 68%, the cellulose-like fraction by 50% and the lignin-like fractions by 12% in the final compost. The TOM losses, compost stabilisation and evolution of the biochemical fractions were similar to observed in large reactors or on-site experiments, excluding the lignin degradation, which was less important than in full-scale systems. The reproducibility of the process and the quality of the final compost make it possible to propose the use of this experimental device for research requiring a mass reduction of the initial composted waste mixtures.

Lashermes, G.; Barriuso, E. [INRA, UMR1091 Environment and Arable Crops (INRA, AgroParisTech), F-78850 Thiverval-Grignon (France); Le Villio-Poitrenaud, M. [VEOLIA Environment - Research and Innovation, F-78520 Limay (France); Houot, S., E-mail: sabine.houot@grignon.inra.fr [INRA, UMR1091 Environment and Arable Crops (INRA, AgroParisTech), F-78850 Thiverval-Grignon (France)

2012-02-15

459

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.

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

2010-01-01

460

Sexual satisfaction and sexual drive in spinal cord injured women.  

PubMed

Levels of sexual satisfaction and sexual drive in women with spinal cord injuries were examined. Eighty-four spinal cord injured (SCI) women and thirty-seven able-bodied (AB) control subjects completed the Derogatis Sexual Functioning Inventory which measured current level of sexual functioning in 10 areas: information, experience, drive, attitude, psychological symptoms, affect, gender role definition, fantasy, body image, and sexual satisfaction. When compared with AB women, SCI women had significantly lower levels of sexual satisfaction and sexual drive and significantly higher levels of psychological symptoms and negative affect. Among SCI women, sexual satisfaction decreased significantly with age. Among AB women, sexual satisfaction increased significantly with age. Married SCI women were no longer less sexually satisfied than AB women. Results support conclusions from previous self-report studies in which significant decreases in sexual satisfaction and drive were reported for SCI women. Implications for continued research on the psychological and physiological aspects of sexuality and sexual functioning in SCI women are discussed. PMID:9863935

Black, K; Sipski, M L; Strauss, S S

1998-07-01

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