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1

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

Microsoft Academic Search

BACKGROUND: Darwin's evolutionary theory could easily explain the evolution of adaptive traits (organs and behavioral patterns) in asexual but not in sexual organisms. Two models, the selfish gene theory and frozen plasticity theory were suggested to explain evolution of adaptive traits in sexual organisms in past 30 years. RESULTS: The frozen plasticity theory suggests that sexual species can evolve new

Jaroslav Flegr

2010-01-01

2

Repeat swimming performance and its implications for inferring the relative fitness of asexual hybrid dace (Pisces: Phoxinus) and their sexually reproducing parental species.  

PubMed

While theories explaining the evolution and maintenance of sex are abundant, empirical data on the costs and benefits of asexual relative to sexual reproduction are less common. Asexually reproducing vertebrates, while few, provide a rare opportunity to measure differences in fitness between asexual and sexual species. All known asexually reproducing vertebrates are of hybrid origin, and hybrid disadvantage (i.e., reduced hybrid fitness) is thought to facilitate long-term coexistence between asexual and sexual species. We used repeat swimming performance as a proxy for fitness to compare the fitness of asexual hybrid dace (Pisces: Phoxinus) and their sexually reproducing parental species, finescale dace (Phoxinus neogaeus) and northern redbelly dace (Phoxinus eos). We tested the prediction that, given the widespread coexistence of these hybrid and parental dace, the parental species should show equivalent and perhaps superior repeat performance relative to hybrids. A repeat constant acceleration test (U(max)) was conducted at both acclimation temperature (16 °C) and at an elevated temperature (25 °C) to simulate the combined influence of a repeat swim and acute temperature change that fish might experience in the wild. The asexual hybrids performed more poorly than at least one of the parental species. There was a negative effect of temperature on repeat swimming performance in all fish, and the repeat performance of hybrids was more severely affected by temperature than that of finescale dace. No difference in the effect of temperature on repeat performance was detected between hybrids and northern redbelly dace. These results suggest that hybrids suffer physiological costs relative to the parentals or at least that the hybrids do not gain advantage from hybrid vigor, which probably contributes to the coexistence of asexual and sexual species in this system. PMID:21527822

Mee, Jonathan A; Brauner, Colin J; Taylor, Eric B

2011-01-01

3

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. PMID:22479465

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

2012-01-01

4

Laboratory synthesis of an independently reproducing vertebrate species  

PubMed Central

Speciation in animals commonly involves an extrinsic barrier to genetic exchange followed by the accumulation of sufficient genetic variation to impede subsequent productive interbreeding. All-female species of whiptail lizards, which originated by interspecific hybridization between sexual progenitors, are an exception to this rule. Here, the arising species instantaneously acquires a novel genotype combining distinctive alleles from two different species, and reproduction by parthenogenesis constitutes an effective intrinsic barrier to genetic exchange. Fertilization of diploid parthenogenetic females by males of sexual species has produced several triploid species, but these instantaneous speciation events have neither been observed in nature nor have they been reconstituted in the laboratory. Here we report the generation of four self-sustaining clonal lineages of a tetraploid species resulting from fertilization of triploid oocytes from a parthenogenetic Aspidoscelis exsanguis with haploid sperm from Aspidoscelis inornata. Molecular and cytological analysis confirmed the genetic identity of the hybrids and revealed that the females retain the capability of parthenogenetic reproduction characteristic of their triploid mothers. The tetraploid females have established self-perpetuating clonal lineages which are now in the third generation. Our results confirm the hypothesis that secondary hybridization events can lead to asexual lineages of increased ploidy when favorable combinations of parental genomes are assembled. We anticipate that these animals will be a critical tool in understanding the mechanisms underlying the origin and subsequent evolution of asexual amniotes. PMID:21543715

Lutes, Aracely A.; Baumann, Diana P.; Neaves, William B.; Baumann, Peter

2011-01-01

5

Laboratory synthesis of an independently reproducing vertebrate species.  

PubMed

Speciation in animals commonly involves an extrinsic barrier to genetic exchange followed by the accumulation of sufficient genetic variation to impede subsequent productive interbreeding. All-female species of whiptail lizards, which originated by interspecific hybridization between sexual progenitors, are an exception to this rule. Here, the arising species instantaneously acquires a novel genotype combining distinctive alleles from two different species, and reproduction by parthenogenesis constitutes an effective intrinsic barrier to genetic exchange. Fertilization of diploid parthenogenetic females by males of sexual species has produced several triploid species, but these instantaneous speciation events have neither been observed in nature nor have they been reconstituted in the laboratory. Here we report the generation of four self-sustaining clonal lineages of a tetraploid species resulting from fertilization of triploid oocytes from a parthenogenetic Aspidoscelis exsanguis with haploid sperm from Aspidoscelis inornata. Molecular and cytological analysis confirmed the genetic identity of the hybrids and revealed that the females retain the capability of parthenogenetic reproduction characteristic of their triploid mothers. The tetraploid females have established self-perpetuating clonal lineages which are now in the third generation. Our results confirm the hypothesis that secondary hybridization events can lead to asexual lineages of increased ploidy when favorable combinations of parental genomes are assembled. We anticipate that these animals will be a critical tool in understanding the mechanisms underlying the origin and subsequent evolution of asexual amniotes. PMID:21543715

Lutes, Aracely A; Baumann, Diana P; Neaves, William B; Baumann, Peter

2011-06-14

6

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

7

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. PMID:15294768

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

2004-01-01

8

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

PubMed

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

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

2014-08-01

9

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

10

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

PubMed Central

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

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

2012-01-01

11

The relationship between reproductive state and "sexually" dimorphic brain areas in sexually reproducing and parthenogenetic whiptail lizards.  

PubMed

The anterior hypothalamus-preoptic area and ventromedial hypothalamus are sexually dimorphic in the reproductively active whiptail lizard Cnemidophorus inornatus. The anterior hypothalamus-preoptic area, which is involved in the control of male-typical copulatory behaviors, is larger in males, whereas the ventromedial hypothalamus, which is involved in the control of female-typical receptivity, is larger in females. In the parthenogenetic whiptail lizard C. uniparens, which is a direct descendant of C. inornatus and exhibits both male-like and female-like pseudosexual behaviors, both brain areas are comparable in size to those of female C. inornatus. This study was conducted to determine whether these brain areas change in size in either species or sex during a time of year when these animals are reproductively inactive, or after removal of the gonads. In male C. inornatus both brain areas changed during reproductive inactivity (either seasonally or surgically induced) and became equivalent to the size characteristic of reproductively active female C. inornatus. When corrected for brain size, the anterior hypothalamus-preoptic area was significantly smaller in intact hibernating and castrated males than in intact males from the summer breeding season. Conversely, the ventromedial hypothalamus was significantly larger in intact hibernating and castrated males than in intact males from the summer breeding season. The two brain areas were not significantly different among the groups of female C. inornatus or parthenogenetic C. uniparens. These results suggest that 1) the brain of whiptail lizards may differentiate seasonally and 2) the female state may be a neutral one to which the male brain reverts during reproductive inactivity. PMID:1918445

Wade, J; Crews, D

1991-07-22

12

Sexual dimorphisms in the soma size of neurons in the brain of whiptail lizards (Cnemidophorus species).  

PubMed

Soma area was significantly larger in the anterior hypothalamus-preoptic area of male than female Cnemidophorus inornatus, and it was significantly larger in females than males in the ventromedial hypothalamus. These results parallel those on the volume of the brain areas in these animals, and therefore probably explain at least part of the dimorphisms seen in this sexually reproducing species. Soma size in parthenogenetic C. uniparens also parallels volume. PMID:1450958

Wade, J; Crews, D

1992-10-30

13

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

Microsoft Academic Search

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

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

1994-01-01

14

Disentangling precopulatory and postcopulatory sexual selection in polyandrous species.  

PubMed

Sexual selection operates on a sequence of events, from mating to offspring production. Which stages in this sequence undergo stronger selection, especially the relative importance of pre- versus postcopulatory processes, are intensely debated issues. Unequal siring success among mates of polyandrous females is classically taken as evidence for a large contribution of postcopulatory processes to the variance in male reproductive success (var(RSm )). However, paternity skews also depend on the timing and number of copulations, a source of variation that should be considered precopulatory rather than postcopulatory. We develop a method for decomposing var(RSm ) accounting for copulatory activity and apply it to experimental mating groups of the snail Physa acuta. In our experiment, 40% of var(RSm ) emerges at the precopulatory stage, only half of which depends on variation in mating success (number of partners). Ignoring copulation characteristics can therefore lead to severe underestimation of precopulatory sexual selection. Moreover, although only 36% of var(RSm ) arises at the postcopulatory stage, this is when sexual selection on body weight mostly occurs. Finally, trade-offs were detected between different components of precopulatory success, whereas pre- and postcopulatory success appear independent. Our study opens the way to a detailed quantitative understanding of sexual selection in polyandrous species. PMID:24410424

Pélissié, Benjamin; Jarne, Philippe; Sarda, Violette; David, Patrice

2014-05-01

15

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

PubMed Central

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

Avise, John C.; Walker, DeEtte

1999-01-01

16

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

PubMed

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

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

2014-10-01

17

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

Microsoft Academic Search

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

A. Berglund; G. Rosenqvist; I. Svensson

1986-01-01

18

The counterintuitive role of sexual selection in species maintenance and speciation  

PubMed Central

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

Servedio, Maria R.; Burger, Reinhard

2014-01-01

19

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. PMID:22219309

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

20

Incidence of insecticide resistance alleles in sexually-reproducing populations of the peach-potato aphid Myzus persicae (Hemiptera: Aphididae) from southern France.  

PubMed

Intensive chemical treatments have led to the development of a number of insecticide resistance mechanisms in the peach-potato aphid Myzus persicae (Sulzer). Some of these mechanisms are known to be associated with negative pleiotropic effects (resistance costs). Molecular and biochemical methods were used to determine the genotypes or phenotypes associated with four insecticide resistance mechanisms in single aphids from sexually-reproducing populations in southern France. The mechanisms considered were E4 and FE4 carboxylesterase overproduction, modified acetycholinesterase, and kdr and rdl resistance-associated mutations. A new method for determining individual kdr genotypes is presented. Almost all resistant individuals overproduced FE4 carboxylesterase, whereas modified acetylcholinesterase was rare. Both the kdr and rdl resistance mutations were present at high frequencies in French sexually-reproducing populations. The frequencies of insecticide resistance genes were compared before and after sexual reproduction in one peach orchard at Avignon to evaluate the potential impact of selection on the persistence of resistance alleles in the over-wintering phase. The frequencies of the kdr and rdl mutations varied significantly between autumn and spring sampling periods. The frequency of the kdr mutation increased, probably due to pyrethroid treatments at the end of the winter. Conversely, the frequency of the rdl mutation decreased significantly during winter, probably because of a fitness cost associated with this mutation. PMID:12908914

Guillemaud, T; Guillemaud, T; Brun, A; Anthony, N; Sauge, M-H; Boll, R; Delorme, R; Fournier, D; Lapchin, L; Vanlerberghe-Masutti, F

2003-08-01

21

Uncoupling of sexual reproduction from homologous recombination in homozygous Oenothera species  

PubMed Central

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

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

2011-01-01

22

Sexual differentiation in the spiny softshell turtle (Apalone spinifera), a species with genetic sex determination  

Microsoft Academic Search

It is hypothesized on the basis of sex determination theory that species exhibiting genetic sex determination (GSD) may undergo sexual differentiation earlier in development than species with environmental sex determination (ESD). Most turtle species exhibit a form of ESD known as temperature-dependent sex determination (TSD), and in such species the chronology of sex differentiation is well studied. Apalone spinifera is

Eli Greenbaum; John L. Carr

2001-01-01

23

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

24

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. PMID:23717085

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

2011-01-01

25

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

PubMed Central

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

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

2012-01-01

26

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

E-print Network

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

27

Vol. 150, No. 1 The American Naturalist July 1997 COMPARISONS OF PHYSIOLOGICAL PERFORMANCE IN SEXUAL  

E-print Network

IN SEXUAL AND ASEXUAL WHIPTAIL LIZARDS (GENUS CNEMIDOPHORUS): IMPLICATIONS FOR THE ROLE OF HETEROZYGOSITY of asexual and sexual species of the lizard genus Cnemi- dophorus. Asexual species of the genus are parthenogenetically reproducing hybrids of the sexual species and as a result have high levels of heterozygosity

Burk, Theodore E.

28

Sexual isolation between two sibling species with overlapping ranges: Drosophila santomea and Drosophila yakuba.  

PubMed

Drosophila yakuba is widespread in Africa, whereas D. santomea, its newly discovered sister species, is endemic to the volcanic island of São Tomé in the Gulf of Guinea. Drosophila santomea probably formed after colonization of the island by a D. yakuba-like ancestor. The species presently have overlapping ranges on the mountain Pico do São Tomé, with some hybridization occurring in this region. Sexual isolation between the species is uniformly high regardless of the source of the populations, and, as in many pairs of Drosophila species, is asymmetrical, so that hybridizations occur much more readily in one direction than the other. Despite the fact that these species meet many of the conditions required for the evolution of reinforcement (the elevation of sexual isolation by natural selection to avoid maladaptive interspecific hybridization), there is no evidence that sexual isolation between the species is highest in the zone of overlap. Sexual isolation is due to evolutionary changes in both female preference for heterospecific males and in the vigor with which males court heterospecific females. Heterospecific matings are also slower to take place than are homospecific matings, constituting another possible form of reproductive isolation. Genetic studies show that, when tested with females of either species, male hybrids having a D. santomea X chromosome mate much less frequently with females of either species than do males having a D. yakuba X chromosome, suggesting that the interaction between the D. santomea X chromosome and the D. yakuba genome causes behavioral sterility. Hybrid F1 females mate readily with males of either species, so that sexual isolation in this sex is completely recessive, a phenomenon seen in other Drosophila species. There has also been significant evolutionary change in the duration of copulation between these species; this difference involves genetic changes in both sexes, with at least two genes responsible in males and at least one in females. PMID:12583583

Coyne, Jerry A; Kim, Soo Y; Chang, Audrey S; Lachaise, Daniel; Elwyn, Susannah

2002-12-01

29

Gender differences in species recognition and the evolution of asymmetric sexual isolation.  

PubMed

Closely related sympatric species are expected to evolve strong species discrimination because of the reinforcement of mate preferences. Fitness costs of heterospecific matings are thought to be higher in females than in males, and females are therefore expected to show stronger species discrimination than males. Here, we investigated gender and species differences in sexual isolation in a sympatric species pair of Calopteryx damselflies. The genus Calopteryx is one of the classic examples of reproductive character displacement in evolutionary biology, with exaggerated interspecific differences in the amount of dark wing coloration when species become sympatric. Experimental manipulation of the extent of dark wing coloration revealed that sexual isolation results from both female and male mate discrimination and that wing melanization functions as a species recognition character. Female choice of conspecific males is entirely based on wing coloration, whereas males in one species also use other species recognition cues in addition to wing color. Stronger species discrimination ability in males is presumably an evolutionary response to an elevated male predation risk caused by conspicuous wing coloration. Gender differences in species discrimination and fitness costs of male courtship can thus shed new light on the evolution of asymmetric sexual isolation and the reinforcement of mate preferences. PMID:17935996

Svensson, Erik I; Karlsson, Kristina; Friberg, Magne; Eroukhmanoff, Fabrice

2007-11-20

30

Sexual differentiation in the spiny softshell turtle (Apalone spinifera), a species with genetic sex determination.  

PubMed

It is hypothesized on the basis of sex determination theory that species exhibiting genetic sex determination (GSD) may undergo sexual differentiation earlier in development than species with environmental sex determination (ESD). Most turtle species exhibit a form of ESD known as temperature-dependent sex determination (TSD), and in such species the chronology of sex differentiation is well studied. Apalone spinifera is a species of softshell turtle (Trionychidae) that exhibits GSD. We studied sexual differentiation in this species in order to facilitate comparison to TSD species. Eggs were incubated at two different temperatures and embryos were harvested at various stages of mid to late development. Gonad length was measured with image analysis software, then prepared histologically. Indifferent gonads have differentiated in stage 19 embryos. Histological details of gonadogenesis follow the same pattern as described for other reptiles. Regression of the male paramesonephric duct closely follows testicular differentiation. Gonad lengths are longer at the warmer incubation temperature, and ovaries are generally longer than testes at each stage and for each temperature. Although sexual differentiation takes place at about the same stage as in other turtles with TSD (18-20), in A. spinifera this differentiation is irreversible at this stage, while in some of the TSD species sex is reversible until about stage 22. This immutable, definitive sexual differentiation may support the hypothesis of an accelerated chronology of sex differentiation for this species. We also note that sexual dichromatism at hatching is known in this species and may provide additional evidence of early differentiation. J. Exp. Zool. 290:190-200, 2001. PMID:11471149

Greenbaum, E; Carr, J L

2001-07-01

31

Chance Establishment for Sexual, Semelparous Species: Overcoming the Allee Effect  

Microsoft Academic Search

We formalize the establishment process for a sexual, semelparous\\u000a organism through the use of hierarchical probability modeling from\\u000a parameters of survival, probability of being female, probability of\\u000a being fertilized, and expected fecundity. We show how to calculate the\\u000a expected per capita growth rate and probability of extinction. An Allee\\u000a effect is observed if the expected population growth rate decreases as

Christopher L. Jerde

2009-01-01

32

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

PubMed Central

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

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

2014-01-01

33

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

PubMed Central

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

Birky, C. William

2013-01-01

34

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

35

Sexual Dimorphism in the Sceloporus undulatus Species Complex  

E-print Network

that in some horned lizard species body size does increase fecundity. However an increase in the degree of SSD does not yield a fecundity advantage in P. hernandesi (Zamudio 1998). I note however that body shape in the 21 genus Phrynosoma evolved...

Dittmer, Drew

2012-10-19

36

Conflicting preferences within females: sexual selection versus species recognition.  

PubMed

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. PMID:21367782

Rosenthal, Gil G; Ryan, Michael J

2011-08-23

37

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

PubMed Central

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

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

2014-01-01

38

Asexual and sexual reproductive strategies in clonal plants  

Microsoft Academic Search

Most plants can reproduce both sexually and asexually (or vegetatively), and the balance between the two reproductive modes\\u000a may vary widely between and within species. Extensive clonal growth may affect the evolution of life history traits in many\\u000a ways. First, in some clonal species, sexual reproduction and sex ratio vary largely among populations. Variation in sexual\\u000a reproduction may strongly affect

Yufen Zhang; Dayong Zhang

2007-01-01

39

Sexual imprinting misguides species recognition in a facultative interspecific brood parasite  

PubMed Central

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

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

2010-01-01

40

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

PubMed

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

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

2010-10-22

41

Prenatal sex ratios and expression of sexually dimorphic traits in three snake species.  

PubMed

Variation in intrauterine exposure to hormones associated with variation in the sex of litter mates has well-established and far-reaching effects on sexual development in some mammals. Research on this phenomenon in reptiles is scant, but suggests that lizards may follow the mammalian model whereas snakes may be affected differently. We examined sex-specific expression of four sexually dimorphic traits (tail length, head length, ventral scale count, swimming speed) in three species of snakes (Nerodia sipedon, Thamnophis sirtalis, T. sauritus) relative to litter sex ratios. We found little evidence that traits in either sex were masculinized or feminized in response to variation in litter sex ratio. The one significant result appeared best explained as a statistical artifact attributable to a single litter. Our results indicate that snakes are different from the one lizard studied to date. Unlike previous suggestions that prenatal hormonal mechanisms operate differently in snakes and lizards, however, the difference appears to be that development of sexually dimorphic traits in lizards is affected by litter sex ratios whereas in snakes it is not. PMID:16788914

Weatherhead, Patrick James; Kissner, Kelley Joan; Sommerer, Sophie Jane

2006-08-01

42

Behavioural display systems across nine Anolis lizard species: sexual dimorphisms in structure and function  

PubMed Central

Relationships between structure and function are a primary focus in biology, yet they are most often considered within individual species. Sexually dimorphic communication behaviours and the morphology of associated structures can vary widely, even among closely related species, and these traits provide an ideal opportunity to investigate the evolution of structure–function patterns. Using nine Anolis lizard species, we addressed a series of questions regarding sex differences in and the evolution of relationships between extension of the throat fan (dewlap) and morphology of the muscles and cartilage controlling it. The main results indicated that within species, males displayed the dewlap more often than females and consistently exhibited larger associated structures. These data are consistent with work in other vertebrates in which corresponding sex differences in reproductive morphology and behaviour have been documented. Across species, however, we found no evidence that the rate of dewlap extension evolved in association with dewlap morphology. Thus, we provide an example of traits that, when considered in a phylogenetic framework, exhibited limited associations between behaviour and morphology, perhaps as the result of constraints imposed by the ecological contexts in which different species occur. PMID:20129985

Johnson, Michele A.; Wade, Juli

2010-01-01

43

Genetic structure of two protist species (Myxogastria, Amoebozoa) suggests asexual reproduction in sexual Amoebae.  

PubMed

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. PMID:21829662

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

2011-01-01

44

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

PubMed Central

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

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

2004-01-01

45

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

E-print Network

imprinting Social experience Sexual differentiation Homosexual behavior a b s t r a c t A majority of birds they are expressed in reproduc- tively active adults [24]. Across species, one of the most widespread and pronounced

46

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

PubMed Central

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

Webb, Thomas J.; Freckleton, Robert P.

2007-01-01

47

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

48

Nuptial gifts and sexual behavior in two species of spider (Araneae, Trechaleidae, Paratrechalea)  

NASA Astrophysics Data System (ADS)

Male delivering of a prey packed in silk as a nuptial gift is rare in spiders and restricted until now to Pisauridae. Here, we describe this behavioral pattern found in two Trechaleidae species, Paratrechalea azul Carico 2005, and Paratrechalea ornata (Mello-Leitão 1943), mainly based on field observations. We observed the following steps of sexual behavior: sperm induction, nuptial gift construction, mate searching, pre-copulatory courtship, copulation, and copulatory ending. In this group, a nuptial gift consists of a prey wrapped in silk, which appears as a white rounded shape. The male carries his nuptial gift in his chelicerae while searching for a female. When he finds a female, he shows a stereotyped courting behavior consisting of a hyperflexed posture that is also assumed by the receptive female while they face each other. The copulatory position and pattern is similar to that found in other Lycosoidea: the male mounts the female and makes a total of four palpal insertions while alternating sides. However, after each palpal insertion the male dismounts and returns to a frontal position while biting the gift. Copulatory courtship is evidenced by palpal and leg movements. The copulation ends by female initiative and she almost always retains the nuptial gift. No case of pre-copulatory or post-copulatory cannibalism has been recorded. Descriptions of nuptial gift construction by males and copulation in these species, as well as hypotheses about the origin of nuptial gift construction among spiders, are presented. These descriptions are the first records of such nuptial gift offering for Neotropical spiders and for non-Pisauridae species as well.

Costa-Schmidt, Luiz Ernesto; Carico, James Edwin; de Araújo, Aldo Mellender

2008-08-01

49

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

PubMed Central

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

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

2005-01-01

50

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

PubMed Central

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

Oneal, Elen; Knowles, L. Lacey

2013-01-01

51

Discovery of a Modified Tetrapolar Sexual Cycle in Cryptococcus amylolentus and the Evolution of MAT in the Cryptococcus Species Complex  

PubMed Central

Sexual reproduction in fungi is governed by a specialized genomic region called the mating-type locus (MAT). The human fungal pathogenic and basidiomycetous yeast Cryptococcus neoformans has evolved a bipolar mating system (a, ?) in which the MAT locus is unusually large (>100 kb) and encodes >20 genes including homeodomain (HD) and pheromone/receptor (P/R) genes. To understand how this unique bipolar mating system evolved, we investigated MAT in the closely related species Tsuchiyaea wingfieldii and Cryptococcus amylolentus and discovered two physically unlinked loci encoding the HD and P/R genes. Interestingly, the HD (B) locus sex-specific region is restricted (?2 kb) and encodes two linked and divergently oriented homeodomain genes in contrast to the solo HD genes (SXI1?, SXI2a) of C. neoformans and Cryptococcus gattii. The P/R (A) locus contains the pheromone and pheromone receptor genes but has expanded considerably compared to other outgroup species (Cryptococcus heveanensis) and is linked to many of the genes also found in the MAT locus of the pathogenic Cryptococcus species. Our discovery of a heterothallic sexual cycle for C. amylolentus allowed us to establish the biological roles of the sex-determining regions. Matings between two strains of opposite mating-types (A1B1×A2B2) produced dikaryotic hyphae with fused clamp connections, basidia, and basidiospores. Genotyping progeny using markers linked and unlinked to MAT revealed that meiosis and uniparental mitochondrial inheritance occur during the sexual cycle of C. amylolentus. The sexual cycle is tetrapolar and produces fertile progeny of four mating-types (A1B1, A1B2, A2B1, and A2B2), but a high proportion of progeny are infertile, and fertility is biased towards one parental mating-type (A1B1). Our studies reveal insights into the plasticity and transitions in both mechanisms of sex determination (bipolar versus tetrapolar) and sexual reproduction (outcrossing versus inbreeding) with implications for similar evolutionary transitions and processes in fungi, plants, and animals. PMID:22359516

Fraser, James A.; Hsueh, Yen-Ping; Averette, Anna Floyd; Li, Wenjun; Dietrich, Fred S.; Heitman, Joseph

2012-01-01

52

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

PubMed

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

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

2005-01-01

53

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

Microsoft Academic Search

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

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

2011-01-01

54

Sexual dimorphism of AMH, DMRT1 and RSPO1 localization in the developing gonads of six anuran species.  

PubMed

In vertebrates, several genes which are differentially expressed in various species, have been implicated in sex determination and gonadal differentiation. We used immunolocalization to study the expression pattern of three proteins AMH, DMRT1, RSPO1 involved in the sexual differentiation of gonads. The pattern of AMH, DMRT1 and RSPO1 expression was analyzed in X. laevis and in five other divergent anuran species: Bombina bombina, Bufo viridis, Hyla arborea, Rana arvalis and Rana temporaria during gonadal development. The pattern of expression of AMH in the developing testes of six studied anuran species was similar to that described for other vertebrates. AMH was strongly expressed in differentiating Sertoli cells. Interestingly, in B. viridis, R. arvalis and R. temporaria, AMH was also expressed in ovaries. In all studied species, DMRT1 was highly expressed in the developing testes, in both the somatic and germ cells. It was also expressed at low level in ovaries in all studied species, with the exception of H. arborea. RSPO1 was expressed in the developing ovaries, especially in the somatic cells, and was almost undetectable in developing testes in all examined anurans. These developmental expression patterns strongly suggest an involvement of AMH and DMRT1 in the development of male gonads and of RSPO1 in the female gonads. The differences in the expression patterns of these proteins in the gonads of different species might reflect the diversity of gonadal development patterns in anurans resulting from long lasting and diverged paths of their evolution. PMID:24623081

Piprek, Rafal P; Pecio, Anna; Laskowska-Kaszub, Katarzyna; Kubiak, Jacek Z; Szymura, Jacek M

2013-01-01

55

The influence of geographic heterogeneity in predation pressure on sexual signal divergence in an Amazonian frog species complex.  

PubMed

Sexual selection plays an important role in mating signal divergence, but geographic variation in ecological factors can also contribute to divergent signal evolution. We tested the hypothesis that geographic heterogeneity in predation causes divergent selection on advertisement call complexity within the Engystomops petersi (previously Physalaemus petersi) frog species complex. We conducted predator phonotaxis experiments at two sites where female choice is consistent with call trait divergence. Engystomops at one site produces complex calls, whereas the closely related species at the other site produces simple calls. Bats approached complex calls more than simple calls at both sites, suggesting selection against complex calls. Moreover, bat predation pressure was greater at the site with simple calls, suggesting stronger selection against complex calls and potentially precluding evolution of complex calls at this site. Our results show that geographic variation in predation may play an important role in the evolution and maintenance of mating signal divergence. PMID:23181745

Trillo, P A; Athanas, K A; Goldhill, D H; Hoke, K L; Funk, W C

2013-01-01

56

How Do Beetles Reproduce?  

NSDL National Science Digital Library

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

Drnevich, Jenny

2009-07-02

57

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

PubMed Central

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

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

2011-01-01

58

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

PubMed

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

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

2011-01-01

59

The immunocompetence handicap hypothesis in two sexually dimorphic pinniped species—is there a sex difference in immunity during early development?  

Microsoft Academic Search

The ‘immunocompetence handicap hypothesis’ predicts that highly sexually dimorphic and polygynous species will exhibit sex differences in immunity. We tested this hypothesis in southern elephant and grey seals during their early development by measuring the following parameters: leucocyte counts, serum IgG levels, erythrocyte sedimentation rate and haematocrit. We failed to find any differences due to sex as assessed by the

Ailsa J Hall; Georg H Engelhard; Sophie M. J. M Brasseur; Anna Vecchione; Harry R Burton; Peter J. H Reijnders

2003-01-01

60

Abstract In most species, only one sex searches for mates while the other waits. Models of sex-specific  

E-print Network

· Sexual conflict · Density effects · Predation effects · Fiddler crabs Introduction Sexually reproducing in the fiddler crab Uca beebei. U. beebei is one of the few fiddler-crab species in which both sexes search for mates. In a field experiment conducted in Panama, we manipulated crab density and perceived predation

61

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

Microsoft Academic Search

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

David R. Stanley

1988-01-01

62

Sexual differences in postingestive processing of dietary protein and carbohydrate in caterpillars of two species.  

PubMed

Previous studies indicated that female Heliothis virescens and Estigmene acrea caterpillars use both feeding and postingestive processing as mechanisms to meet nutrient demands. We present utilization and nutrient budget data on the postingestive partitioning of nutrients into pre- and postabsorptive components. Both species utilized carbohydrate efficiently except at very high ingestion rates. Of the carbohydrate utilized, more was unaccounted for as intake increased, and we assume the material unaccounted for served as a respiratory substrate. In contrast, the pattern of nitrogen utilization differed between the species. Larval H. virescens efficiently retained nitrogen except at very high ingestion rates, whereas E. acrea progressively increased nitrogen egestion in response to increased nitrogen ingestion. Overall, females of both species utilized nitrogen more efficiently than did males at most ingestion levels, thus contributing to the greater protein-derived growth we previously reported. In addition, for H. virescens, protein and amino acids accounted for a small proportion of fecal nitrogen so that most of the fecal nitrogen was of a postabsorptive nature. In contrast, nitrogen excreted by E. acrea could be partitioned into both pre- and postabsorptive components. The manner of postingestive processing by these two species reflects differences in their larval diet. PMID:12794678

Telang, Aparna; Buck, Norman A; Chapman, Reginald F; Wheeler, Diana E

2003-01-01

63

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

PubMed Central

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

Ward, Jessica L; Blum, Michael J

2012-01-01

64

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

2006-08-01

65

Reproducing in Cities  

Microsoft Academic Search

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

Ruth Mace

2008-01-01

66

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

PubMed

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

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

2012-04-01

67

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. PMID:10581276

Macdonald, S J; Goldstein, D B

1999-01-01

68

Sexual Assault  

MedlinePLUS

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

69

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

70

Magnetogastrography (MGG) Reproducibility Assessments  

NASA Astrophysics Data System (ADS)

Seven healthy subjects underwent a magnetic pulse of 32 mT for 17 ms, seven times in 90 minutes. The procedure was repeated one and two weeks later. Assessments of the gastric emptying were carried out for each one of the measurements and a statistical analysis of ANOVA was performed for every group of data. The gastric emptying time was 19.22 ± 5 min. Reproducibility estimation was above 85%. Therefore, magnetogastrography seems to be an excellent technique to be implemented in routine clinical trials.

de la Roca-Chiapas, J. M.; Córdova, T.; Hernández, E.; Solorio, S.; Solís Ortiz, S.; Sosa, M.

2006-09-01

71

Sexual Conflict and Sexually Antagonistic Coevolution in an Annual Plant  

PubMed Central

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

Madjidian, Josefin A.; Lankinen, Asa

2009-01-01

72

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

PubMed

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 been conclusively demonstrated in several species, particularly members of the holarctic genus Andricus. This raises the possibility of widespread secondary loss of sex in the Cynipini, and of diversification within purely parthenogenetic lineages. We use two approaches based on analyses of allele frequency data to test for cryptic sexual generations in eight apparently asexual European species distributed through a major western palaearctic lineage of the gallwasp genus Andricus. All species showing adequate levels of polymorphism (7/8) showed signatures of sex compatible with cyclical parthenogenesis. We also use DNA sequence data to test the hypothesis that ignorance of these sexual generations (despite extensive study on this group) results from failure to discriminate among known but morphologically indistinguishable sexual generations. This hypothesis is supported: 35 sequences attributed by leading cynipid taxonomists to a single sexual adult morphospecies, Andricus burgundus, were found to represent the sexual generations of at least six Andricus species. We confirm cryptic sexual generations in a total of 11 Andricus species, suggesting that secondary loss of sex is rare in Andricus. PMID:18086197

Stone, Graham N; Atkinson, Rachel J; Rokas, Antonis; Aldrey, José-Luis Nieves; Melika, George; Acs, Zoltan; Csóka, György; Hayward, Alexander; Bailey, Richard; Buckee, Caroline; McVean, Gilean A T

2008-01-01

73

Evolution of neuroendocrine mechanisms that regulate sexual behavior.  

PubMed

Whiptail lizards provide a unique system to study evolution of brain mechanisms because both ancestral (sexual) and descendant (parthenogenetic) species exist. Parthenogenetic whiptails enable us to avoid the two major confounds in sex differences research - males and females that differ both genetically and hormonally. Parthenogens are females that reproduce clonally, yet display alternately female-like and male-like pseudosexual behavior. Thus, the neural circuitry underlying male and female sexual behavior can be examined within the 'same' brain (same genome), enabling us to see how neuroendocrine mechanisms controlling mounting behavior change. In ancestral males, testicular androgens control sexual behavior, whereas male-like pseudocopulatory behavior is controlled by ovarian progesterone in parthenogens, revealing that progesterone is important in regulating sexual behavior in male vertebrates, including mammals. PMID:16139506

Crews, David

2005-10-01

74

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. PMID:3467325

Crews, D; Grassman, M; Lindzey, J

1986-01-01

75

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

76

sexual Assault sexual Assault  

E-print Network

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

Hickman, Mark

77

Sexual strategies theory: Historical origins and current status  

Microsoft Academic Search

In sexually reproducing organisms, no domain is more closely linked with the engine of the evolutionary process than sexuality. Men and women over human evolutionary history have confronted different adaptive problems in the sexual domain. Sexual Strategies Theory offers an account of these adaptive problems and presents a view of human sexual psychology as a rich repertoire of mechanisms that

David M. Buss

1998-01-01

78

Sexual dimorphism in animals  

NSDL National Science Digital Library

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

Olivia Worland (Purdue University;Biological Sciences)

2008-05-23

79

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

2013-02-01

80

Assessment of genetic relationships among sexual and asexual forms of Allium cepa using morphological traits and RAPD markers  

Microsoft Academic Search

The species Allium cepa includes two major crops on the basis of morphological traits and typical reproduction mode: sexually reproduced biennial onions and vegetatively propagated perennial shallots which rarely flower. In addition, the seed-propagated shallot, a recently released variety with intermediate phenotype for life history, has been described and used by breeders. A joint analysis using molecular markers (random amplified

Maud Le Thierry D'Ennequin; Olivier Panaud; Thierry Robert; Agnès Ricroch

1997-01-01

81

Short-term population differences in the genetic architecture of life history traits related to sexuality in an aphid species  

Microsoft Academic Search

One of the most important factors that determine the evolutionary trajectory of a suite of traits in a population is the structure of the genetic variance–covariance matrix (G). We studied the cyclically parthenogenetic aphid Rhopalosiphum padi, whose populations exhibit two types of reproductive lineages respectively specialized in sexuality (that is, cyclically parthenogenetic lineages) and in asexuality (that is, obligate parthenogenetic

R F Nespolo; C C Figueroa; M Plantegenest; J C Simon

2008-01-01

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. PMID:20071382

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

2010-01-01

84

Sexual Assault  

MedlinePLUS

... for Patients Share This Page: Sexual Assault Resources Sexual Assault Sexual assault is a significant problem affecting American ... National Network at 1-800-656-HOPE (4673). Sexual Assault Examinations It is important to know that a ...

85

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

PubMed Central

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

Clark, L V; Jasieniuk, M

2012-01-01

86

Evolutionary biology Sexual ornamentation  

E-print Network

range of bacterial species [10]. Sperm protection via antibacterial substances would maintain maleEvolutionary biology Sexual ornamentation reflects antibacterial activity of ejaculates in mallards the antibacterial activity of semen from mallard ducks (Anas platyrhynchos) and tested whether the bactericidal

Richner, Heinz

87

Reevolution of sexuality breaks Dollo's law.  

PubMed

The dominance of sexual reproduction is still an unresolved enigma in evolutionary biology. Strong advantages of sex have to exist, because only a few parthenogenetic taxa persist over evolutionary timescales. Oribatid mites (Acari) include outstanding exceptions to the rule that parthenogenetically reproducing taxa are of recent origin and doomed to extinction. In addition to the existence of large parthenogenetic clusters in oribatid mites, phylogenetic analyses of this study and model-based reconstruction of ancestral states of reproduction imply that Crotoniidae have reevolved sexuality from parthenogenetic ancestors within one of those clusters. This reversal in reproductive mode is unique in the animal kingdom and violates Dollo's law that complex ancestral states can never be reacquired. The reevolution of sexuality requires that ancestral genes for male production are maintained over evolutionary time. This maintenance likely is true for oribatid mites because spanandric males exist in various species, although mechanisms that enable the storage of genetically ancestral traits are unclear. Our findings present oribatid mites as a unique model system to explore the evolutionary significance of parthenogenetic and sexual reproduction. PMID:17438282

Domes, Katja; Norton, Roy A; Maraun, Mark; Scheu, Stefan

2007-04-24

88

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

89

ATTEMPTS TO REPRODUCE RHEUMATIC FEVER IN ANIMALS  

PubMed Central

Experiments have been described in which we attempted to reproduce in animals the lesions characteristic of rheumatic fever in the human. A large number of animals representing 7 species was employed. Among other materials, streptococci isolated in pure culture from the blood of rheumatic patients (proved to be so by biopsy or by autopsy) as well as whole blood, plasma, serum, pericardial, pleural and hydrocele fluid, filtrates from tonsils, subcutaneous nodules, lymph nodes, and nasopharyngeal washings obtained from such patients were used in a variety of combinations and with a number of procedures calculated to predispose the animal to the disease. A discussion is given of the criteria whose fulfillment is essential for the establishment of the experimental production of rheumatic disease in animals. Judged by these criteria, we have failed to reproduce the disease. This conclusion, we believe, holds true for all the work thus far reported in the literature. PMID:19869605

Gross, Louis; Loewe, Leo; Eliasoph, Benjamin

1929-01-01

90

Sexual Problems  

MedlinePLUS Videos and Cool Tools

... or constant. Sexual disorders can affect men and women and are classified into four categories: desire disorders, ... the time. Sexual disorders affect both men and women and are classified into 4 main categories: sexual ...

91

Healthy Sexuality  

MedlinePLUS Videos and Cool Tools

... or her sexuality. Let’s talk about how a woman’s body responds to sexual stimulation. During sexual arousal, blood flow increases to a woman’s genitals. Her vagina is lubricated by secretions from ...

92

Sexual Assault  

MedlinePLUS

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

93

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

PubMed Central

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

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

2012-01-01

94

Towards reproducible, scalable lateral molecular electronic devices  

NASA Astrophysics Data System (ADS)

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

Durkan, Colm; Zhang, Qian

2014-08-01

95

Reactive oxygen species generated by microbial NADPH oxidase NoxA regulate sexual development in Aspergillus nidulans  

Microsoft Academic Search

Summary NADPH oxidases (Nox) have been characterized as higher eukaryotic enzymes used deliberately to pro- duce reactive oxygen species (ROS). The recent dis- covery of new functional members of the Nox family in plants and animals has led to the recognition of the increasing importance of ROS as signals involved in regulation of diverse cellular processes such as defence, growth

Teresa Lara-Ortíz; Héctor Riveros-Rosas; Jesús Aguirre

96

Swarming Behavior, Sexual Dimorphism, and Female Reproductive Status in the Sex Role-Reversed Dance Fly Species Rhamphomyia marginata  

Microsoft Academic Search

Dance flies are predaceous insects which often form male mating swarms. In many species males prior to swarming catch an insect prey, which is presented to the female at mating. In Rhamphomyia marginata, females in contrast to males gather to swarm, while males carrying a prey visit swarms for mating. Here I describe the swarming and courtship behavior in R.

Bo G. Svensson

1997-01-01

97

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

Microsoft Academic Search

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

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

1997-01-01

98

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

PubMed Central

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

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

2012-01-01

99

Triploid planarian reproduces truly bisexually with euploid gametes produced through a different meiotic system between sex.  

PubMed

Although polyploids are common among plants and some animals, polyploidization often causes reproductive failure. Triploids, in particular, are characterized by the problems of chromosomal pairing and segregation during meiosis, which may cause aneuploid gametes and results in sterility. Thus, they are generally considered to reproduce only asexually. In the case of the Platyhelminthes Dugesia ryukyuensis, populations with triploid karyotypes are normally found in nature as both fissiparous and oviparous triploids. Fissiparous triploids can also be experimentally sexualized if they are fed sexual planarians, developing both gonads and other reproductive organs. Fully sexualized worms begin reproducing by copulation rather than fission. In this study, we examined the genotypes of the offspring obtained by breeding sexualized triploids and found that the offspring inherited genes from both parents, i.e., they reproduced truly bisexually. Furthermore, meiotic chromosome behavior in triploid sexualized planarians differed significantly between male and female germ lines, in that female germ line cells remained triploid until prophase I, whereas male germ line cells appeared to become diploid before entry into meiosis. Oocytes at the late diplotene stage contained not only paired bivalents but also unpaired univalents that were suggested to produce diploid eggs if they remained in subsequent processes. Triploid planarians may therefore form euploid gametes by different meiotic systems in female and male germ lines and thus are be able to reproduce sexually in contrast to many other triploid organisms. PMID:24402417

Chinone, Ayako; Nodono, Hanae; Matsumoto, Midori

2014-06-01

100

Sexual reproduction and population dynamics: the role of polygyny and demographic sex differences.  

PubMed Central

Most models of population dynamics do not take sexual reproduction into account (i.e., they do not consider the role of males). However, assumptions behind this practice--that no demographic sex differences exist and males are always abundant enough to fertilize all the females--are usually not justified in natural populations. On the contrary, demographic sex differences are common, especially in polygynous species. Previous models that consider sexual reproduction report a stabilizing effect through mixing of different genotypes, thus suggesting a decrease in the propensity for complex of dynamics in sexually reproducing populations. Here we show that considering the direct role of males in reproduction and density dependence leads to the conclusion that a two-sex model is not necessarily more stable compared with the corresponding one-sex model. Although solutions exist where sexual reproduction has a stabilizing effect even when no genotypic variability is included (primarily when associated with monogamy), factors like polygyny, sex differences in survival or density dependence, and possible alterations of the primary sex ratio (the Trivers-Willard mechanism), may enlarge the parametric region of complex dynamics. Sexual reproduction therefore does not necessarily increase the stability of population dynamics and can have destabilizing effects, at least in species with complicated mating systems and sexual dimorphism. PMID:9606132

Lindström, J; Kokko, H

1998-01-01

101

Internet Sexualities  

Microsoft Academic Search

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

Nicola Döring

2010-01-01

102

Increased reproductive effort results in male-biased offspring sex ratio: an experimental study in a species with reversed sexual size dimorphism.  

PubMed Central

Adaptive sex-ratio theory predicts that parents should overproduce the more beneficial offspring sex. Based on a recent experimental study of lesser black-backed gulls, we tested this hypothesis with the great skua, Catharacta skua, a bird species closely related to gulls but where females are the larger sex. When in poor body condition, the gulls overproduced daughters, the smaller and more viable sex under those circumstances. To discriminate between a mandatory physiological overproduction of female (i.e. non-male) eggs versus the overproduction of the smaller and presumably more viable sex, we conducted an egg-removal experiment with the great skua. Since the males are smaller, larger size and being male are separated. Through egg removal we induced females to increase egg production effort. Eggs were sexed using a DNA-based technique. Manipulated pairs produced a significant male bias at the end of the extended laying sequence, while the sex ratio in the control group did not differ from unity. Our results present an example of facultative sex-ratio manipulation and support the hypothesis that in sexually dimorphic birds parents overproduce the smaller sex under adverse conditions. PMID:11600083

Kalmbach, E.; Nager, R. G.; Griffiths, R.; Furness, R. W.

2001-01-01

103

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

104

A bisexually reproducing all-triploid vertebrate.  

PubMed

Green toads are common in the Palaearctic region, where they have differentiated into several taxa. The toads exist with variable amounts of ploidy, similar to other anuran species or reptiles. In vertebrate biology, the very rare occurrence of triploidy is coupled with infertility or unisexuality, or requires the coexistence of individuals of different ploidy in a reproductive community. The reproduction of naturally occurring triploids has been reported to occur only through parthenogenesis, gynogenesis or hybridogenesis. The bisexual reproduction of pure triploids has been considered to be impossible because of the problem of equally distributing three chromosome sets in meiosis. Here we report geographically isolated populations of green toads (Bufo viridis complex) that are all-triploid and reproduce bisexually. PMID:11836500

Stöck, Matthias; Lamatsch, Dunja K; Steinlein, Claus; Epplen, Jörg T; Grosse, Wolf-Rüdiger; Hock, Robert; Klapperstück, Thomas; Lampert, Kathrin P; Scheer, Ulrich; Schmid, Michael; Schartl, Manfred

2002-03-01

105

Quantizations from reproducing kernel spaces  

SciTech Connect

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

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

2013-05-15

106

Sexual Health  

MedlinePLUS

... them do, even if interest in sex and sexual activity declines to some extent with increasing age. This ... and a quarter report no pleasure from their sexual activity. About one out of 10 older women have ...

107

Sexual Abuse  

MedlinePLUS

... form of non-consensual physical contact. It includes rape, molestation, or any sexual conduct with a person ... more? "Speaking the unspeakable: An interview about elder sexual assault with Holly Ramsey-Klawsnik, Ph.D" in nexus , ...

108

Sexuality Education.  

ERIC Educational Resources Information Center

Explores the state of sexuality education in the United States. After concerted efforts in the 1960s to stop sex education, interest in sexuality education resurged in the 1980s, largely as a result of AIDS fears. There is now a broad-based consensus on the necessity of sexuality education, but there are still few effective programs. (SLD)

Haffner, Debra W.

1998-01-01

109

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

110

Cloning to reproduce desired genotypes  

Microsoft Academic Search

Cloned sheep, cattle, goats, pigs and mice have now been produced using somatic cells for nuclear transplantation. Animal cloning is still very inefficient with on average less than 10% of the cloned embryos transferred resulting in a live offspring. However successful cloning of a variety of different species and by a number of different laboratory groups has generated tremendous interest

M. E. Westhusin; C. R. Long; T. Shin; J. R. Hill; C. R. Looney; J. H. Pryor; J. A. Piedrahita

2001-01-01

111

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

PubMed Central

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

2010-01-01

112

Allelic and genotypic diversity in long-term asexual populations of the pea aphid, Acyrthosiphon pisum in comparison with sexual populations.  

PubMed

Many aphid species exhibit geographical variation in the mode of reproduction that ranges from cyclical parthenogenesis with a sexual phase to obligate parthenogenesis (asexual reproduction). Theoretical studies predict that organisms reproducing asexually should maintain higher allelic diversity per locus but lower genotypic diversity than organisms reproducing sexually. To corroborate this hypothesis, we evaluated genotypic and allelic diversities in the sexual and asexual populations of the pea aphid, Acyrthosiphon pisum (Harris). Microsatellite analysis revealed that populations in central Japan are asexual, whereas populations in northern Japan are obligatorily sexual. No mixed populations were detected in our study sites. Phylogenetic analysis using microsatellite data and mitochondrial cytochrome oxidase subunit I (COI) gene sequences revealed a long history of asexuality in central Japan and negated the possibility of the recent origin of the asexual populations from the sexual populations. Asexual populations exhibited much lower genotypic diversity but higher allelic richness per locus than did sexual populations. Asexual populations consisted of a few predominant clones that were considerably differentiated from one another. Sexual populations on alfalfa, an exotic plant in Japan, were most closely related to asexual populations associated with Vicia sativa L. The alfalfa-associated sexual populations harboured one COI haplotype that was included in the haplotype clade of the asexual populations. Available evidence suggests that the sexuality of the alfalfa-associated populations has recently been restored through the northward migration and colonization of alfalfa by V. sativa-associated lineages. Therefore, our results support the theoretical predictions and provide a new perspective on the origin of sexual populations. PMID:19207245

Kanbe, Takashi; Akimoto, Shin-ichi

2009-03-01

113

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. PMID:20862222

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

2010-01-01

114

Are non-sexual models appropriate for predicting the impact of virus-vectored immunocontraception?  

PubMed

In response to the need to efficiently control mammal pest populations while avoiding unnecessary suffering, applied and theoretical ecologists have recently focused on virus-vectored immunocontraception (VVIC). So far, modellers have only considered a non-sexual approach (models of sexually reproducing populations without explicitly discerning between the sexes), which appears dubious in view of the sex-specificity of VVIC agents. In this paper, we derive and compare predictions of non-sexual and two-sex models of the spread of a VVIC agent in a host population in order to assess the adequacy of non-sexual models in this context. Our results show that predictions of non-sexual and two-sex models generally diverge and that non-sexual models often fail to predict the control impact of VVIC. We thus recommend using two-sex models, especially if the mating system and life history of the target species are known. Our analysis also shows that female-specific viruses generally give better results than male-specific ones, and suggests that virus choice should focus more on its sterilizing power rather than transmission efficiency. PMID:17988689

Deredec, Anne; Berec, Ludek; Boukal, David S; Courchamp, Franck

2008-01-21

115

Social implications of the battle of the sexes: sexual harassment disrupts female sociality and social recognition.  

PubMed

Across sexually reproducing species, males and females are in conflict over the control of reproduction. At the heart of this conflict in a number of taxa is male harassment of females for mating opportunities and female strategies to avoid this harassment. One neglected consequence that may result from sexual harassment is the disruption of important social associations. Here, we experimentally manipulate the degree of sexual harassment that wild female guppies (Poecilia reticulata) experience by establishing replicated, semi-natural pools with different population sex ratios. We quantify the effects of sexual harassment on female social structure and the development of social recognition among females. When exposed to sexual harassment, we found that females had more disparate social networks with limited repeated interactions when compared to females that did not experience male harassment. Furthermore, females that did not experience harassment developed social recognition with familiar individuals over an 8-day period, whereas females that experienced harassment did not, an effect we suggest is due to disruption of association patterns. These results show that social network structure and social recognition can be affected by sexual harassment, an effect that will be relevant across taxonomic groups and that we predict will have fitness consequences for females. PMID:19386653

Darden, Safi K; James, Richard; Ramnarine, Indar W; Croft, Darren P

2009-07-22

116

[Sexual orientations].  

PubMed

In this paper we study the concept of sexual orientation and its components by comparing the common orientations of hetero-, homo-, and bisexuality with alternative concepts suitable for describing persons with psychosexual and somatosexual divergencies (e.g., transgender or intersex developments). An assessment of these divergencies as well as their prevalence and societal influences are presented. Empirical findings on the relationship between sexual orientation and mental health are examined against the background of the sexual minority stress model, looking especially at the risks and the opportunities associated with belonging to a sexual minority. The paper also focuses on the normative power of a monosexual model. Finally, sexual orientation is conceptualized as an umbrella term encompassing both conscious and unconscious elements, including the aspects of sexual behavior, sexual identity, fantasies, and attraction. PMID:23361208

Schweizer, K; Brunner, F

2013-02-01

117

Color and Communication in Habronattus Jumping Spiders: Tests of Sexual and Ecological Selection.  

E-print Network

??Differences between males and females can evolve through a variety of mechanisms, including sexual and ecological selection. Because coloration is evolutionarily labile, sexually dichromatic species… (more)

Taylor, Lisa A.

2012-01-01

118

SEXUAL ASSAULT AND SEXUAL HARASSMENT QUICK REFERENCE  

E-print Network

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

Thompson, Michael

119

Sexual behaviour  

PubMed Central

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

Mercer, Catherine H.

2014-01-01

120

Sexual harassment.  

PubMed

We review the current state of sexual harassment theory, research, treatment, and prevention. Definitional problems and implications are discussed. An examination of the epidemiology of sexual harassment is presented, highlighting correlates that include characteristics of the organizational environment, the perpetrator, and the recipient of unwanted sexual behavior. Normative responses to sexual harassment and consequences are discussed. Descriptions of the most prevalent models of sexual harassment are offered and the empirical evidence for them is briefly reviewed. From there, the effect of model development and evaluation on the prevention and treatment of sexual harassment is considered. We comment on the steps that would need to be taken to develop viable prevention and treatment programs. Suggestions for fruitful avenues of research and theory development are offered. PMID:11351834

Sbraga, T P; O'Donohue, W

2000-01-01

121

Adolescent sexuality.  

PubMed

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

Grant, L M; Demetriou, E

1988-12-01

122

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

PubMed Central

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

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

2012-01-01

123

Sex in cheese: evidence for sexuality in the fungus Penicillium roqueforti.  

PubMed

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

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

2012-01-01

124

Reproducible EnzymeReproducible Enzyme Assembly and CatalyticAssembly and Catalytic  

E-print Network

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

Rubloff, Gary W.

125

Sexual Selections: \\  

Microsoft Academic Search

The following selection of papers arose out of a half-year seminar course, The Anthropology of Sex, held at McMaster University in the winter of 1990. The course was originally conceived as a vehicle for scrutinizing the physical anthropological significance of current understandings of human sexuality and reproduction. As such, I imagined we would discuss human sexuality from the point of

Ann Herring

1991-01-01

126

ORIGINAL PAPER Males, but not females, contribute to sexual isolation  

E-print Network

ORIGINAL PAPER Males, but not females, contribute to sexual isolation between two sympatric species; salamanders: Arnold et al. 1993; birds: Sætre et al. 1997a, b; crickets: Jang et al. 2007). Sexual isolation

Gabor, Caitlin - Department of Biology, Texas State University

127

Quasi-convex reproducing kernel meshfree method  

NASA Astrophysics Data System (ADS)

A quasi-convex reproducing kernel approximation is presented for Galerkin meshfree analysis. In the proposed meshfree scheme, the monomial reproducing conditions are relaxed to maximizing the positivity of the meshfree shape functions and the resulting shape functions are referred as the quasi-convex reproducing kernel shape functions. These quasi-convex meshfree shape functions are still established within the framework of the classical reproducing or consistency conditions, namely the shape functions have similar form as that of the conventional reproducing kernel shape functions. Thus this approach can be conveniently implemented in the standard reproducing kernel meshfree formulation without an overmuch increase of computational effort. Meanwhile, the present formulation enables a straightforward construction of arbitrary higher order shape functions. It is shown that the proposed method yields nearly positive shape functions in the interior problem domain, while in the boundary region the negative effect of the shape functions are also reduced compared with the original meshfree shape functions. Subsequently a Galerkin meshfree analysis is carried out by employing the proposed quasi-convex reproducing kernel shape functions. Numerical results reveal that the proposed method has more favorable accuracy than the conventional reproducing kernel meshfree method, especially for structural vibration analysis.

Wang, Dongdong; Chen, Pengjie

2014-09-01

128

Irreproducible Musings on Reproducibility Philip B. Stark  

E-print Network

good. But why? · Reproducibility hard. But why? · Reproducibility hard to sell. But why? · Hard? · Provides (a way to generate) evidence of correctness · Enables re-use, modification, extension was reported to have been done on the processed data? · Was that analysis the right analysis to do

Stark, Philip B.

129

Reproducing Kernel Element Interpolation: Globally Conforming Im  

E-print Network

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

Li, Shaofan

130

Childhood Sexual Abuse, Adolescent Sexual Behaviors and Sexual Revictimization.  

ERIC Educational Resources Information Center

An 18-year longitudinal study of 520 New Zealand women found that those reporting childhood sexual abuse, particularly severe abuse involving intercourse, had significantly higher rates of early onset consensual sexual activity, teenage pregnancy, multiple sexual partners, unprotected intercourse, sexually transmitted disease, and sexual assault…

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

1997-01-01

131

Student Sexual Misconduct Policy  

E-print Network

. PROHIBITED BEHAVIOR a. Definitions i. Sexual Misconduct ii. Sexual Harassment iii. Sexual Assault iv. Consent resources by reading the Campus Sexual Violence Prevention Program and visiting the Sexual Assault Policy, including but not limited to, sexual harassment, sexual assault, stalking, and relationship violence

Huang, Jianyu

132

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

E-print Network

Distribution of Phoxinus eos, Phoxinus neogaeus, and Their Asexually-Reproducing Hybrids (Pisces Biology, University of Toronto, Toronto, Ontario, Canada Abstract Hybrid Phoxinus are one of the few asexually reproducing vertebrates species. The distribution of hybrid Phoxinus among lakes in Algonquin Park

Sokolowski, Marla

133

Reproducing on Time When Temperature Varies: Shifts in the Timing of Courtship by Fiddler Crabs  

E-print Network

Reproducing on Time When Temperature Varies: Shifts in the Timing of Courtship by Fiddler Crabs near the shore during the day. Remarkably, some species, including the fiddler crabs Uca terpsichores. (2014) Reproducing on Time When Temperature Varies: Shifts in the Timing of Courtship by Fiddler Crabs

Collin, Rachel

134

Apomictic and sexual pearl millet X Pennisetum squamulatum hybrids  

SciTech Connect

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

Dujardin, M.; Hanna, W.W.

1983-01-01

135

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

Microsoft Academic Search

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

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

2004-01-01

136

Towards reproducible, scalable lateral molecular electronic devices  

E-print Network

An approach to reproducibly fabricate molecular electronic devices is presented. Lateral nanometer-scale gaps with high yield are formed in Au/Pd nanowires by a combination of electromigration and Joule-heating-induced thermomechanical stress...

Durkan, Colm; Zhang, Qian

2014-08-26

137

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

138

True Nature: A Theory of Human Sexual Evolution. Part 1  

Microsoft Academic Search

There exists an unfounded and unproven ‘common sense’ belief that human beings possess the innate mechanistic urge to reproduce clearly evident in the behavior of all other sexually reproducing animals. As such, the heterosexual component of human behavior is by and large viewed as being genetic, whereas it is homosexuality that is primarily the focus of scientific investigations into human

Christopher A. Gomes

2000-01-01

139

Child Sexual Abuse  

MedlinePLUS

... Enter ZIP code here Enter ZIP code here Child Sexual Abuse Child Sexual Abuse What is child sexual abuse? Child sexual abuse includes a wide ... be at least five years older. Who commits child sexual abuse? Most often, sexual abusers know the ...

140

Sexual Reproduction in a Simple Growth Population Model  

NASA Astrophysics Data System (ADS)

One of the most important characteristics in the survival of a species is related to the kind of reproduction responsible for the offspring generation. However, only in the last years the role played by sexual reproduction has been investigated. Then, for a better understanding of this kind of process we introduce, in this work, a surface reaction model that describes the role of the sexual reproduction. In our model two different elements of the species, representing male and female, can interact to reproduce a new element. The sex of this new element is chosen with a given probability and in order to take into account the mortality rate we introduce another kind of individual. The value of the spatial density of this element remains constant during the time evolution of the system. The model is studied using Monte Carlo simulations and mean field approximation. Depending on the values of the control parameters of the model, the system can attain two stationary states: In one of them the population survives and in the other it can be extinguished. Besides, accordingly to our results, the phase diagram of the model shows a discontinuous transition between these two states.

Lemos, Carlos Gentil Oro; Santos, Marcio

2012-05-01

141

Reproducibility responsibilities in the HPC arena  

SciTech Connect

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

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

2014-01-01

142

[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

2006-01-01

143

A Reproducible Oral Microcosm Biofilm Model for Testing Dental Materials  

PubMed Central

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

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

2012-01-01

144

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

145

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

146

Thoreau's Sexuality  

Microsoft Academic Search

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

Walter Harding

1991-01-01

147

Sexual reproduction in Hawaiian Acropora  

NASA Astrophysics Data System (ADS)

Sexual reproductive maturity was evaluated in Acropora valida, Acropora cytherea and Acropora humilis at French Frigate Shoals, Northwest Hawaiian Islands during two consecutive summers. Acropora valida gonads matured at different rates in different habitats in both years. Spawning was inferred by the sudden disappearance of gonads of mature size. Histological sections of fertile polyps confirmed the maturity of gonads prior to spawning. An isolated colony of A. humilis spawned in early summer. Strong indications of sexually mature colonics of A. cytherea exist, but clear temporal patterns were not apparent. Lunar period of spawning in reef flat A. valida and A. humilis differed from that reported for these species from other regions. The three species did not overlap in time of spawning. Previous ideas concerning the allochthonous origin of larval recruits, as well as the absence of Acropora from high islands of the Hawaiian chain, are re-evaluated in light of new evidence for sexual reproductive capacity by native populations.

Kenyon, Jean C.

1992-04-01

148

Sexual Reproductive Biology of a Colonial Rotifer Sinantherina socialis (Rotifera: Monogononta): Do mating strategies vary between colonial and solitary rotifer species?  

PubMed Central

In many aquatic invertebrates including monogonont rotifers, sex provides genetic variation and dormant stages that allows dispersal in time and space. While the reproductive biology of some solitary monogonont rotifer species is known, little is known concerning mating behaviors in colonial rotifers. Coloniality poses unique challenges to the typical mating behavior of solitary rotifers. For instance, most species engage in circling behavior, where the male swims in close proximity to the female. In colonial forms, access to a particular female may be hindered by nearby colony mates. Here we provide descriptions of (1) male morphology, (2) mating behavior, and (3) types of eggs of the widespread colonial rotifer Sinantherina socialis, and discuss modifications in mating strategies as a consequence of coloniality. Two important differences from mating patterns documented in solitary rotifers were found in S. socialis. First, duration of circling phase of mating is protracted for males encountering small colonies of females as compared to solitary females. Males encountering single females removed from their colonies behave similarly to those of solitary species. Second, duration of copulation in S. socialis is the shortest reported for any rotifer species. Endogamy might occur in this species as sons copulate with their sisters and mothers, at least under laboratory conditions. Examples of behaviour in linked video clips. PMID:24932095

Rico-Martínez, Roberto; Walsh, Elizabeth J.

2014-01-01

149

Sexuality I. Sexual Orienta0on  

E-print Network

1 Sexuality I. Sexual Orienta0on II. Hormones & cogni0on III. The Female sexual Behavior of the Human Female (1953) by A. Kinsey #12;2 II. Hormones, Cogni0on & Learning A and female-typical sexual behaviors in vertebrates 1. Testosterone ­ Posi0ve rela0onship

Dever, Jennifer A.

150

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. PMID:18391518

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

2008-01-01

151

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

152

Supplemental Figure 1 Reproducibility of biological replicates.  

E-print Network

Supplemental Figure 1 Reproducibility of biological replicates. (A) Pairwise comparisons of three. In these replicates the SILAC labels were switched, hence the negative correlation. Supplemental Figure 2 Curation in the SCUD database with those identified in this publication. Supplemental Figure 3 Changes in the Ub

Martin, Alain

153

Reproducibility in Ultrasonic Characterization of Carotid Plaques  

Microsoft Academic Search

Background and Purpose: Echolucent carotid plaques compared with echogenic plaques could carry a significant risk of transient ischemic attacks and strokes, but the reproducibility of new ultrasonic methods has not yet been proved. The objective was to evaluate interobserver and intraobserver agreement in characterizing the carotid plaques studied by both B mode imaging and color Doppler imaging, which is the

J. M. de Bray; J. M. Baud; P. Delanoy; J. P. Camuzat; V. Dehans; J. Descamp-Le Chevoir; J. R. Launay; F. Luizy; Y. Sentou; P. Cales

1998-01-01

154

Reproducibility, Controllability, and Optimization of Lenr Experiments  

NASA Astrophysics Data System (ADS)

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

Nagel, David J.

2006-02-01

155

Reproducibility, Controllability, and Optimization of Lenr Experiments  

Microsoft Academic Search

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

David J. Nagel

2006-01-01

156

Human Computation Must Be Reproducible Praveen Paritosh  

E-print Network

Human Computation Must Be Reproducible Praveen Paritosh Google 345 Spear St, San Francisco, CA 94105. pkp@google.com ABSTRACT Human computation is the technique of performing a com- putational and evaluation of experiments. We argue that human computation has similar properties, and that the results

Tomkins, Andrew

157

Is My Network Module Preserved and Reproducible?  

Microsoft Academic Search

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

Peter Langfelder; Rui Luo; Michael C. Oldham; Steve Horvath; Philip E. Bourne

2011-01-01

158

Reproducible Measurements of MPI Performance Characteristics  

E-print Network

of the mistakes often made in attempting such mea- surements and the consequences of such mistakes. We describe, that attempts to avoid such mistakes and obtain reproducible measures of MPI performance that can be useful, Information, and Computational Sci- ences Division subprogram of the Office of Advanced Scientific Computing

Gropp, Bill

159

Natural Disasters: Earth Science Readings. Reproducibles.  

ERIC Educational Resources Information Center

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

Lobb, Nancy

160

Reproducible Clusters from Microarray Research: Whither?  

Microsoft Academic Search

MOTIVATION: In cluster analysis, the validity of specific solutions, algorithms, and procedures present significant challenges because there is no null hypothesis to test and no 'right answer'. It has been noted that a replicable classification is not necessarily a useful one, but a useful one that characterizes some aspect of the population must be replicable. By replicable we mean reproducible

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

2005-01-01

161

Intraspecific sexual preferences of female hamsters  

Microsoft Academic Search

Studied the sexual preference behavior of 32 estrous females of 3 species of hamsters of the genus Mesocricetus by introducing individual females into an arena with a pair of males from 2 different species. When 1 male of the pair was a conspecific, females of all 3 species spent significantly more time investigating the conspecific male. When neither male was

Michael R. Murphy

1977-01-01

162

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

163

ITK: enabling reproducible research and open science  

PubMed Central

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

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

2014-01-01

164

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

165

Sexual size dimorphism in anurans.  

PubMed Central

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

Monnet, Jean-Matthieu; Cherry, Michael I

2002-01-01

166

The coevolution of cell senescence and diploid sexual reproduction in unicellular organisms  

PubMed Central

In this paper, we investigate the coevolution of diploid sexual reproduction and cell senescence (i.e., cell aging). We use probability analysis, computer simulation, and exact numerical computation to analyze the impacts of deleterious recessive mutations on sexual and asexual reproduction. The main conclusion is that, without cell senescence, the evolutionary advantages of sexual reproduction cannot be realized in unicellular organisms that reproduce both sexually and asexually. Also, cell senescence is found to be useful in the maintenance of sexual reproduction. This result suggests that diploid sexual reproduction was unlikely to establish itself as a widespread reproduction mechanism without the complementary process of cell senescence. PMID:10737794

Cui, Yan; Chen, Run Sheng; Wong, Wing Hung

2000-01-01

167

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

168

Senescing sexual ornaments recover after a sabbatical  

PubMed Central

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

2010-01-01

169

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

170

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

171

[Sexual mutilation].  

PubMed

Sexual mutilation (SM) of women is an old tradition that predates Christianity and Islam. There are 4 types of SM (female circumcision): 1) clitorectomy; 2) infibulation; 3) introcision and 4) mutilation of the sexual organs. The 4 major justifications for the SM of women are: 1) the mythological rationale or Divine Androgony. All people arrive on Earth as androgens and as the 1st God; they have a female element, the clitoris for the boys and a male element, the penis for the girls. To remove that original stage of androgeny requires circumcision and excision; 2) the religious rationale in spite of its predating Islam the Prophet Mohammed recommended a mild form of clitorectomy (Sunna); 3) the sexual rationale this is the universal reason why, worldwide, women are excised and infibulated. Excision is performed to control women's sexuality permanently and infibulation is performed to control procreation. Traditional Africans perform excision and circumcision for reasons of socialization--that is it allows the individual to go from one group to the next; 4) the cleanliness rationale non-excised women are not clean. SM is practiced when little girls are very young because they are less sensitive to the pain; however, there is no exact age and SM can be performed after age 8, during adolescence, before marriage and during the 7th month of pregnancy. Medicalized or clinical excisions performed in hospitals with anesthesia and antibiotics; however, traditional excision is practiced in the rural areas with untrained personnel and without anesthesia, often leading to many genital and medical complications. The worst of these is being unable to consummate marriage and having difficult pregnancies. Women should refuse medicalization of an act that destroys a health organ; this system that allows men to enjoy as much sex as possible and promotes women's passive attitudes towards SM, must be changed. PMID:12342831

Kouyate, H

1990-07-01

172

A meshfree unification: reproducing kernel peridynamics  

NASA Astrophysics Data System (ADS)

This paper is the first investigation establishing the link between the meshfree state-based peridynamics method and other meshfree methods, in particular with the moving least squares reproducing kernel particle method (RKPM). It is concluded that the discretization of state-based peridynamics leads directly to an approximation of the derivatives that can be obtained from RKPM. However, state-based peridynamics obtains the same result at a significantly lower computational cost which motivates its use in large-scale computations. In light of the findings of this study, an update to the method is proposed such that the limitations regarding application of boundary conditions and the use of non-uniform grids are corrected by using the reproducing kernel approximation.

Bessa, M. A.; Foster, J. T.; Belytschko, T.; Liu, Wing Kam

2014-06-01

173

Consequences of sex-specific growth on sibling competition in black-headed gulls: a sexually-size dimorphic species with scramble competition  

Microsoft Academic Search

Biased mortality of the larger sex during the early developmental period has been reported for a number of size-dimorphic\\u000a bird species. This can partly be explained by the fact that growing to larger size renders the larger sex more vulnerable\\u000a to food shortage. However, since sibling rivalry is often size-dependent, chicks of the larger sex should have a competitive\\u000a advantage.

Wendt Müller; Ton G. G. Groothuis; Cor Dijkstra

2007-01-01

174

Reproducibility of 3D chromatin configuration reconstructions.  

PubMed

It is widely recognized that the three-dimensional (3D) architecture of eukaryotic chromatin plays an important role in processes such as gene regulation and cancer-driving gene fusions. Observing or inferring this 3D structure at even modest resolutions had been problematic, since genomes are highly condensed and traditional assays are coarse. However, recently devised high-throughput molecular techniques have changed this situation. Notably, the development of a suite of chromatin conformation capture (CCC) assays has enabled elicitation of contacts-spatially close chromosomal loci-which have provided insights into chromatin architecture. Most analysis of CCC data has focused on the contact level, with less effort directed toward obtaining 3D reconstructions and evaluating the accuracy and reproducibility thereof. While questions of accuracy must be addressed experimentally, questions of reproducibility can be addressed statistically-the purpose of this paper. We use a constrained optimization technique to reconstruct chromatin configurations for a number of closely related yeast datasets and assess reproducibility using four metrics that measure the distance between 3D configurations. The first of these, Procrustes fitting, measures configuration closeness after applying reflection, rotation, translation, and scaling-based alignment of the structures. The others base comparisons on the within-configuration inter-point distance matrix. Inferential results for these metrics rely on suitable permutation approaches. Results indicate that distance matrix-based approaches are preferable to Procrustes analysis, not because of the metrics per se but rather on account of the ability to customize permutation schemes to handle within-chromosome contiguity. It has recently been emphasized that the use of constrained optimization approaches to 3D architecture reconstruction are prone to being trapped in local minima. Our methods of reproducibility assessment provide a means for comparing 3D reconstruction solutions so that we can discern between local and global optima by contrasting solutions under perturbed inputs. PMID:24519450

Segal, Mark R; Xiong, Hao; Capurso, Daniel; Vazquez, Mariel; Arsuaga, Javier

2014-07-01

175

Sexual selection, sexual size dimorphism and Rensch's rule in Odonata.  

PubMed

Odonata (dragonflies and damselflies) exhibit a range of sexual size dimorphism (SSD) that includes species with male-biased (males > females) or female-biased SSD (males < females) and species exhibiting nonterritorial or territorial mating strategies. Here, we use phylogenetic comparative analyses to investigate the influence of sexual selection on SSD in both suborders: dragonflies (Anisoptera) and damselflies (Zygoptera). First, we show that damselflies have male-biased SSD, and exhibit an allometric relationship between body size and SSD, that is consistent with Rensch's rule. Second, SSD of dragonflies is not different from unit, and this suborder does not exhibit Rensch's rule. Third, we test the influence of sexual selection on SSD using proxy variables of territorial mating strategy and male agility. Using generalized least squares to account for phylogenetic relationships between species, we show that male-biased SSD increases with territoriality in damselflies, but not in dragonflies. Finally, we show that nonagile territorial odonates exhibit male-biased SSD, whereas male agility is not related to SSD in nonterritorial odonates. These results suggest that sexual selection acting on male sizes influences SSD in Odonata. Taken together, our results, along with avian studies (bustards and shorebirds), suggest that male agility influences SSD, although this influence is modulated by territorial mating strategy and thus the likely advantage of being large. Other evolutionary processes, such as fecundity selection and viability selection, however, need further investigation. PMID:18636976

Serrano-Meneses, M A; Córdoba-Aguilar, A; Azpilicueta-Amorín, M; González-Soriano, E; Székely, T

2008-09-01

176

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

177

Reproducibility of Magnetic Resonance Perfusion Imaging  

PubMed Central

Dynamic MR biomarkers (T2*-weighted or susceptibility-based and T1-weighted or relaxivity-enhanced) have been applied to assess tumor perfusion and its response to therapies. A significant challenge in the development of reliable biomarkers is a rigorous assessment and optimization of reproducibility. The purpose of this study was to determine the measurement reproducibility of T1-weighted dynamic contrast-enhanced (DCE)-MRI and T2*-weighted dynamic susceptibility contrast (DSC)-MRI with two contrast agents (CA) of different molecular weight (MW): gadopentetate (Gd-DTPA, 0.5 kDa) and Gadomelitol (P792, 6.5 kDa). Each contrast agent was tested with eight mice that had subcutaneous MDA-MB-231 breast xenograft tumors. Each mouse was imaged with a combined DSC-DCE protocol three times within one week to achieve measures of reproducibility. DSC-MRI results were evaluated with a contrast to noise ratio (CNR) efficiency threshold. There was a clear signal drop (>95% probability threshold) in the DSC of normal tissue, while signal changes were minimal or non-existent (<95% probability threshold) in tumors. Mean within-subject coefficient of variation (wCV) of relative blood volume (rBV) in normal tissue was 11.78% for Gd-DTPA and 6.64% for P792. The intra-class correlation coefficient (ICC) of rBV in normal tissue was 0.940 for Gd-DTPA and 0.978 for P792. The inter-subject correlation coefficient was 0.092. Calculated Ktrans from DCE-MRI showed comparable reproducibility (mean wCV, 5.13% for Gd-DTPA, 8.06% for P792). ICC of Ktrans showed high intra-subject reproducibility (ICC?=?0.999/0.995) and inter-subject heterogeneity (ICC?=?0.774). Histograms of Ktrans distributions for three measurements had high degrees of overlap (sum of difference of the normalized histograms <0.01). These results represent homogeneous intra-subject measurement and heterogeneous inter-subject character of biological population, suggesting that perfusion MRI could be an imaging biomarker to monitor or predict response of disease. PMID:24587040

Zhang, Xiaomeng; Pagel, Mark D.; Baker, Amanda F.; Gillies, Robert J.

2014-01-01

178

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

179

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

180

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

181

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

182

Child abuse - sexual  

MedlinePLUS

... sexual activities by another person. Such abuse includes: Oral sex Pornography Sexual intercourse Touching (fondling) ... and street drugs or engaging in high-risk sexual behaviors Do poorly in school Have excessive fears Withdraw ...

183

Toddlers and Sexual Behavior  

MedlinePLUS

... Commons Pediatrics Common Questions, Quick Answers Toddlers and Sexual Behavior Donna D'Alessandro, M.D. Lindsay Huth, B. ... behavioral problem or sexual abuse. What kind of sexual behaviors are okay? Masturbation in toddlers is usually nothing ...

184

Military Sexual Trauma  

MedlinePLUS

... 8255 Military One Source 800-342-9647 Military Sexual Assault SafeHelpline 877-995-5247 87 reads Home Topics ... experienced a sexual trauma. Sexual trauma (harassment, assault, rape and associated violence) can trigger a range of ...

185

Ethnicity and sexuality  

E-print Network

?sexual ?degenerates?? and ?in- ferior races.? Sexualized racism, homophobia, and misogyny were all foils against which propagandists contrasted the superior morality and sexuality of fascist na- tionalists across Europe (Boyarin 1997, Spackman 1996...

Nagel, Joane

2000-01-01

186

University of California Policy Sexual Harassment and Sexual Violence  

E-print Network

includes sexual assault, rape, #12;University of California Policy Sexual Harassment and Sexual Violence 1 of 20 Academic Student prohibits sexual harassment and sexual violence, and that such behavior violates both law and University

Jacobs, Lucia

187

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

2012-04-23

188

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. PMID:20498705

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

2010-01-01

189

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

190

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

191

Contributions to reproducible CPV outdoor power ratings  

NASA Astrophysics Data System (ADS)

Methodologies that aim to obtain a reproducible power rating are still under discussion at the WG7 of the IEC and there is a need for feedback from real field application in order to validate or improve these methods. These procedures are evaluated through the outdoor rating of seven modules from four different CPV technologies, which have been measured at the CEA outdoor monitoring bench at the Institut National de l'Energie Solaire (INES) site. The benefit of introducing other procedural considerations is analyzed, namely the inclusion of spectrally-corrected irradiance, the utilization of lens temperature as a new parameter for regressions and the optimization of dataset filtering.

Besson, Pierre; Domínguez, César; Baudrit, Mathieu

2014-09-01

192

Reproducibility Data on SUMMiT  

SciTech Connect

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

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

1999-07-16

193

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

194

Impact of Child Sexual Abuse on Developing Sexuality  

Microsoft Academic Search

This article reviews theoretical and empirical literature on sexual abuse and focuses on the effects of child sexual abuse on developing sexuality. The issues addressed include (a) prominent family qualities associated with sexual socialization, (b) theoretical formulations that account for the effects of sexual abuse on developing sexuality, and (c) research findings on the impact of child sexual abuse on

Deborah Tharinger

1990-01-01

195

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

196

Sexual Assault Support Resources  

E-print Network

Sexual Assault Support Resources #12;#12;IIf you have been sexually assaulted it can have a serious're not comfortable with. If the sexual assault has occurred in the last 24 to 72 hours, it is usually recommended resource, as appropriate. #12;ON-CAMPUSRESOURCES WHAT TO EXPECT FROM: SEXUAL ASSAULT SURVIVORS' SUPPORT

197

Sexual Problems of Counselees.  

ERIC Educational Resources Information Center

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

Heritage, Jeannette G.; West, W. Beryl

198

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

199

Military Sexual Trauma  

MedlinePLUS

October, 2014 What is military sexual trauma (MST)? Military sexual trauma, or MST, is the term used by VA to refer to experiences of sexual ... diagnosis, and Veterans’ current treatment needs will vary. Military Sexual Trauma October, 2014 How can MST affect ...

200

Sexuality and Violence.  

ERIC Educational Resources Information Center

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

Sanctuary, Gerald

201

Sexuality and the law.  

PubMed

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

Portelli, C J

1998-01-01

202

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. PMID:22690019

Boos, Dennis D.; Stefanski, Leonard A.

2011-01-01

203

Repeatability and reproducibility of earprint acquisition.  

PubMed

For all forensic disciplines dealing with identification -- e.g., of glass, tool marks, fibers, faces, fingers, handwriting, speakers -- in which manual (subjective, nonautomated) processes play a role, operator dependencies are relevant. With respect to earprint identification, in the period 2002-2005, the Forensic Ear Identification research project collected a database of 1229 donors, three prints per ear, and laid down a "best practice" for print acquisition. Repeatability and reproducibility aspects of the print acquisition are tested. The study suggests that different operators may acquire prints of differing quality, with equal error rates of the matching system ranging from 9% to 19%. Moreover, it turns out that "matching" earprints are more alike when taken in a consecutive row than when taken on separate occasions. This underlines the importance of (1) studying operator effects, (2) operator training, and (3) not gathering "matching" reference material at the same occasion. PMID:18366563

Alberink, Ivo; Ruifrok, Arnout

2008-03-01

204

Is Grannum grading of the placenta reproducible?  

NASA Astrophysics Data System (ADS)

Current ultrasound assessment of placental calcification relies on Grannum grading. The aim of this study was to assess if this method is reproducible by measuring inter- and intra-observer variation in grading placental images, under strictly controlled viewing conditions. Thirty placental images were acquired and digitally saved. Five experienced sonographers independently graded the images on two separate occasions. In order to eliminate any technological factors which could affect data reliability and consistency all observers reviewed images at the same time. To optimise viewing conditions ambient lighting was maintained between 25-40 lux, with monitors calibrated to the GSDF standard to ensure consistent brightness and contrast. Kappa (?) analysis of the grades assigned was used to measure inter- and intra-observer reliability. Intra-observer agreement had a moderate mean ?-value of 0.55, with individual comparisons ranging from 0.30 to 0.86. Two images saved from the same patient, during the same scan, were each graded as I, II and III by the same observer. A mean ?-value of 0.30 (range from 0.13 to 0.55) indicated fair inter-observer agreement over the two occasions and only one image was graded consistently the same by all five observers. The study findings confirmed the lack of reproducibility associated with Grannum grading of the placenta despite optimal viewing conditions and highlight the need for new methods of assessing placental health in order to improve neonatal outcomes. Alternative methods for quantifying placental calcification such as a software based technique and 3D ultrasound assessment need to be explored.

Moran, Mary; Ryan, John; Brennan, Patrick C.; Higgins, Mary; McAuliffe, Fionnuala M.

2009-02-01

205

Reproducible research: a bioinformatics case study.  

PubMed

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

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

Gentleman, Robert

2005-01-01

206

Sexual arousal, is it for mammals only?  

PubMed Central

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

Ball, Gregory F.; Balthazart, Jacques

2012-01-01

207

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

PubMed Central

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

Meloni, M; Reid, A; Caujape-Castells, J; Marrero, A; Fernandez-Palacios, J M; Mesa-Coelo, R A; Conti, E

2013-01-01

208

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

209

Sexual selection and natural selection in bird speciation  

PubMed Central

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

Price, T.

1998-01-01

210

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

211

Psychology/Zoology 310: Human Sexuality Instructor: Marc Breedlove; 240 Giltner; 355-1749; breedsm@msu.edu  

E-print Network

vertebrates? What is sexual selection and how has it shaped our species? Human sexual anatomy Ch 3 & 4Psychology/Zoology 310: Human Sexuality Instructor: Marc Breedlove; 240 Giltner; 355-1749; breedsm: Human Sexuality 4th Ed. (2012) Simon LeVay & Janice Baldwin. Sinauer Assoc. (ISBN 978

Liu, Taosheng

212

Food choice behaviour may promote habitat specificity in mixed populations of clonal and sexual Potamopyrgus antipodarum  

Microsoft Academic Search

Genetic polymorphism along an environmental gradient may be maintained if disruptive selection on habitat-specific traits leads to a correlated response in traits that reduce gene flow between habitats. We studied a short-distance cline in a population of freshwater snails Potamopyrgus antipodarum in which sexual and clonal snails coexist. Sexuals and clones show a life history cline by depth: snails reproduce

Sonja Negovetic; Jukka Jokela

2000-01-01

213

Reproducibility of binary-mixture toxicity studies.  

PubMed

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

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

2007-01-01

214

10 CFR 1016.35 - Authority to reproduce Restricted Data.  

...false Authority to reproduce Restricted Data. 1016.35 Section 1016.35 Energy...PROVISIONS) SAFEGUARDING OF RESTRICTED DATA Control of Information § 1016.35 Authority to reproduce Restricted Data. Secret Restricted Data will...

2014-01-01

215

Reproducing kernel element method Part III: Generalized enrichment and applications  

E-print Network

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

Li, Shaofan

216

Indian concepts on sexuality.  

PubMed

India is a vast country depicting wide social, cultural and sexual variations. Indian concept of sexuality has evolved over time and has been immensely influenced by various rulers and religions. Indian sexuality is manifested in our attire, behavior, recreation, literature, sculptures, scriptures, religion and sports. It has influenced the way we perceive our health, disease and device remedies for the same. In modern era, with rapid globalization the unique Indian sexuality is getting diffused. The time has come to rediscover ourselves in terms of sexuality to attain individual freedom and to reinvest our energy to social issues related to sexuality. PMID:23858263

Chakraborty, Kaustav; Thakurata, Rajarshi Guha

2013-01-01

217

Experimental challenges to reproduce seismic fault motion  

NASA Astrophysics Data System (ADS)

This presentation briefly reviews scientific and technical development in the studies of intermediate to high-velocity frictional properties of faults and summarizes remaining technical challenges to reproduce nucleation to growth processes of large earthquakes in laboratory. Nearly 10 high-velocity or low to high-velocity friction apparatuses have been built in the last several years in the world and it has become possible now to produce sub-plate velocity to seismic slip rate in a single machine. Despite spreading of high-velocity friction studies, reproducing seismic fault motion at high P and T conditions to cover the entire seismogenic zone is still a big challenge. Previous studies focused on (1) frictional melting, (2) thermal pressurization, and (3) high-velocity gouge behavior without frictional melting. Frictional melting process was solved as a Stefan problem with very good agreement with experimental results. Thermal pressurization has been solved theoretically based on measured transport properties and has been included successfully in the modeling of earthquake generation. High-velocity gouge experiments in the last several years have revealed that a wide variety of gouges exhibit dramatic weakening at high velocities (e.g., Di Toro et al., 2011, Nature). Most gouge experiments were done under dry conditions partly to separate gouge friction from the involvement of thermal pressurization. However, recent studies demonstrated that dehydration or degassing due to mineral decomposition can occur during seismic fault motion. Those results not only provided a new view of looking at natural fault zones in search of geological evidence of seismic fault motion, but also indicated that thermal pressurization and gouge weakening can occur simultaneously even in initially dry gouge. Thus experiments with controlled pore pressure are needed. I have struggled to make a pressure vessel for wet high-velocity experiments in the last several years. A technical difficulty was how to absorb hydrodynamic shock due to abrupt fault motion in the vessel, and this was overcome by pressurizing water in the vessel, acting as pore fluid, using pressurized gas (in other words using gas as a cushion). I will report preliminary experimental results on high-velocity rock-on-rock friction under pore-water pressure. Other technical challenges are (i) how to produce step-change in velocity to see if the framework of rate-and-state friction law holds in high-velocity regime, (ii) how to conduct high-velocity friction experiments in hydrothermal conditions to study frictional properties relevant to slow slip and low-frequency tremors, and (iii) how to conduct high-velocity friction experiments at high normal stresses. The first task became possible with a low to high-velocity apparatus in Beijing and a few other machines, and I will show some preliminary results. There is no fundamental difficulty in (ii) since O-ring is enough to seal piston rotating at a high speed. However, (iii) will be the hardest because of severe thermal fracturing of host rocks that limits the axial stress. Use of aluminum sleeve made it possible to apply the normal stress to about 30 MPa, but new device and a high motor power is needed to go higher normal stress.

Shimamoto, T.

2011-12-01

218

RAPID COMMUNICATION VARROA JACOBSONI DOES REPRODUCE IN WORKER  

E-print Network

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

Paris-Sud XI, Université de

219

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. PMID:21283776

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

2011-01-01

220

Reproducibility and utility of dune luminescence chronologies  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

221

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

PubMed Central

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

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

2013-01-01

222

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.

223

Effects of child and adult sexual abuse on adult sexuality  

Microsoft Academic Search

The differential effects of child and adult sexual abuse on adult sexual functioning were examined. The Golombok Rust Inventory of Sexual Satisfaction (GRISS) and a sexual experiences questionnaire were administered to 201 psychology students at the University of South Florida, 175 of whom were retained in the study. GRISS variables that were analyzed consisted of anorgasmia, sexual avoidance, sexual dissatisfaction,

Marla Green Bartoi; Bill N. Kinder

1998-01-01

224

ORIGINAL PAPER Sexual Victimization, Alcohol Intoxication, Sexual-Emotional  

E-print Network

in the past year, completed childhood sexual abuse (CSA) and adolescent/adult sexual assault(ASA) measures combine to exacerbate their sexual risks. Keywords Child sexual abuse Á Sexual assault Á Alcohol Á Sexual. F. Kajumulo Á J. M. Otto Department of Psychology, University of Washington, Box 351525, Seattle, WA

225

Sexual selection enables long-term coexistence despite ecological equivalence.  

PubMed

Empirical data indicate that sexual preferences are critical for maintaining species boundaries, yet theoretical work has suggested that, on their own, they can have only a minimal role in maintaining biodiversity. This is because long-term coexistence within overlapping ranges is thought to be unlikely in the absence of ecological differentiation. Here we challenge this widely held view by generalizing a standard model of sexual selection to include two ubiquitous features of populations with sexual selection: spatial variation in local carrying capacity, and mate-search costs in females. We show that, when these two features are combined, sexual preferences can single-handedly maintain coexistence, even when spatial variation in local carrying capacity is so slight that it might go unnoticed empirically. This theoretical study demonstrates that sexual selection alone can promote the long-term coexistence of ecologically equivalent species with overlapping ranges, and it thus provides a novel explanation for the maintenance of species diversity. PMID:22466286

M'Gonigle, Leithen K; Mazzucco, Rupert; Otto, Sarah P; Dieckmann, Ulf

2012-04-26

226

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

227

Understanding Sexual Violence  

MedlinePLUS

... based activities that address healthy sexuality and dating relationships. • Helping parents identify and address violent attitudes and behaviors in their kids. • Creating policies at work, at school, and in other places ... relationships. For more examples, see Sexual Violence Prevention: Beginning ...

228

Notes on sexuality & space  

E-print Network

Very little has been written on sexuality in architectural scholarship. Sexuality & Space (Princeton Architectural Press, 1992) contains the proceedings of an eponymous 1990 conference at Princeton University, and was both ...

Jacobson, Samuel Ray

2013-01-01

229

Sexual Problems in Women  

MedlinePLUS

There are many problems that can keep a woman from enjoying sex. They include Lack of sexual ... concerns about marriage or relationship problems. For some women, the problem results from past sexual trauma. Occasional ...

230

Responding to Sexual Assault  

E-print Network

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

Ravikumar, B.

231

Competition between sexual and parthenogenetic Artemia: temperature and strain effects  

Microsoft Academic Search

Previously reported competition experiments among Artemia (brine shrimp) species have not incorporated abiotic variability into their experimental design. Recent field and laboratory investigations point to temperature as a critical factor in determining the biogeographic distribution and competitive ability of sexual and parthenogenetic Artemia.One sexual diploid strain A. tunisiana Bowen (S) and two A. parthenogenetica Barigozzi strains [one diploid (PD) and

Carlos Barata; Francisco Hontoria; Francisco Amat; Robert Browne

1996-01-01

232

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

233

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.

234

Avalon Sexual Assault Centre  

E-print Network

Avalon Sexual Assault Centre www.avaloncentre.ca halifax.ca/MenEndingViolenceAgainstWomen www-494-6400 Dalhousie Security Services ph. 902-494-6400 @dalsecurity #12;Avalon Sexual Assault Centre www;Avalon Sexual Assault Centre www.avaloncentre.ca halifax.ca/MenEndingViolenceAgainstWomen www

Brownstone, Rob

235

Sexual Harassment in Schools.  

ERIC Educational Resources Information Center

Reviews the legal principles and precedents that frame current sexual harassment laws as they relate to schools. Discusses school district liability and responsibility for providing school environments safe from sexual harassment. Includes guidelines for developing and implementing school policies regarding sexual harassment. (CFR)

Mawdsley, Ralph D.

1994-01-01

236

Female Sexual Dysfunction  

MedlinePLUS

... menopause-and-womens-health.cfm North American Menopause Society information about sexual health and menopause: www.menopause.org/ ... em-sexual-health-menopause-em-online Mayo Clinic information about female sexual ... www.hormone.org or call 1-800-HORMONE (1-800-467-6663)

237

SEXUALITY AND GENDER IDENTITY  

E-print Network

LEARN TO UNDERSTAND SEXUALITY AND GENDER IDENTITY COUNSELLING AND PSYCHOLOGICAL SERVICES CAPS #12;CONTENTS 01 Questioning your sexuality or gender identity 02 Coming out 04 Sexual health 05 Harassment (or ever) label yourself as `gay', `lesbian', `bisexual', or even `straight'. Gender identity

Viglas, Anastasios

238

Loneliness and Sexual Dysfunctions.  

ERIC Educational Resources Information Center

Argues that sexual dysfunctions result from early childhood experiences which were originally nonsexual in nature. Contends that psychological difficulties centered around problems of loneliness tend to generate certain sexual dysfunctions. Extends and explores suggestion that genesis of sexual conflicts is in nonsexual infant separation anxiety…

Mijuskovic, Ben

1987-01-01

239

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

240

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

241

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.

242

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

PubMed

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

2013-11-01

243

Sexual Revictimization: The Role of Sexual Self-Esteem and Dysfunctional Sexual Behaviors  

Microsoft Academic Search

Disproportionately high rates of sexual revictimization have been noted among former victims of child sexual abuse (CSA), yet researchers have yet to determine the source of this apparent vulnerability to reexperience sexual violence. This study explores this issue by examining sexual self-esteem, sexual concerns, and sexual behaviors among 402 university women. Compared to women without a history of CSA (n

Lisa K. Van Bruggen; Marsha G. Runtz; Helena Kadlec

2006-01-01

244

Natural and sexual selection against hybrid flycatchers  

PubMed Central

While sexual selection is generally assumed to quickly cause or strengthen prezygotic barriers between sister species, its role in causing postzygotic isolation, through the unattractiveness of intermediate hybrids, is less often examined. Combining 24 years of pedigree data and recently developed species-specific molecular markers from collared (Ficedula albicollis) and pied (Ficedula hypoleuca) flycatchers and their hybrids, we were able to quantify all key components of fitness. To disentangle the relative role of natural and sexual selection acting on F1 hybrid flycatchers, we estimated various fitness components, which when combined represent the total lifetime reproductive success of F1 hybrids, and then compared the different fitness components of F1 hybrids to that of collared flycatchers. Female hybrid flycatchers are sterile, with natural selection being the selective force involved, but male hybrids mainly experienced a reduction in fitness through sexual selection (decreased pairing success and increased rate of being cuckolded). To disentangle the role of sexual selection against male hybrids from a possible effect of genetic incompatibility (on the rate of being cuckolded), we compared male hybrids with pure-bred males expressing intermediate plumage characters. Given that sexual selection against male hybrids is a result of their intermediate plumage, we expect these two groups of males to have a similar fitness reduction. Alternatively, hybrids have reduced fitness owing to genetic incompatibility, in which case their fitness should be lower than that of the intermediate pure-bred males. We conclude that sexual selection against male hybrids accounts for approximately 75% of the reduction in their fitness. We discuss how natural and sexual selection against hybrids may have different implications for speciation and conclude that reinforcement of reproductive barriers may be more likely when there is sexual selection against hybrids. PMID:18211878

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

2008-01-01

245

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. PMID:20816968

Wilczynski, Walter; Lynch, Kathleen S.

2010-01-01

246

Interest in reproducing long-extinct Carolina parakeet surfaces  

NSDL National Science Digital Library

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

247

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. PMID:10523431

Plakun, Eric M.

1999-01-01

248

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

249

Behavioral Facilitation of Reproduction in Sexual and Unisexual Whiptail Lizards  

Microsoft Academic Search

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

David Crews; Mark Grassman; Jonathan Lindzey

1986-01-01

250

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

PubMed Central

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

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

2011-01-01

251

Degradation of sexual reproduction in Veronica filiformis after introduction to Europe  

PubMed Central

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

2012-01-01

252

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

PubMed

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

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

2011-07-12

253

The Reciprocal Relationship Between Sexual Victimization and Sexual Assertiveness  

PubMed Central

Low sexual assertiveness has been proposed as a possible mechanism through which sexual revictimization occurs, yet evidence for this has been mixed. In this study, prospective path analysis was used to examine the relationship between sexual refusal assertiveness and sexual victimization over time among a community sample of women. Results provide support for a reciprocal relationship, with historical victimization predicting low sexual assertiveness and low sexual assertiveness predicting subsequent victimization. The effect of recent sexual victimization on subsequent sexual assertiveness also was replicated prospectively. These findings suggest that strengthening sexual assertiveness may help reduce vulnerability to future victimization. PMID:17322273

Livingston, Jennifer A.; Testa, Maria; VanZile-Tamsen, Carol

2007-01-01

254

Sexually Selected Infanticide in a Polygynous Bat  

PubMed Central

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

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

2011-01-01

255

Evolution of neuroendocrine mechanisms that regulate sexual  

E-print Network

, USA Whiptail lizards provide a unique system to study evolu- tion of brain mechanisms because both ancestral (sexual) and descendant (parthenogenetic) species exist. Parthe- nogenetic whiptails enable us of ecological and evolutionary processes'. The whiptail lizards (genus Cnemidophorus) are such a system

Dever, Jennifer A.

256

Brandeis University prohibits all forms of sexual misconduct (including sexual  

E-print Network

Brandeis University prohibits all forms of sexual misconduct (including sexual assault, sexual of the resources below for help. A RESOURCE GUIDE FOR SExUAl ASSAUlt SURVIVORS Updated May 2014 Office Of c AND ASSISTANCE Sexual assault Services and prevention Specialist Sheila McMahon 781-736-3626 smcmahon

Snider, Barry B.

257

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

258

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

259

SexualHarassment Yale University statement on sexual harassment  

E-print Network

performance or creating an intimidating or hostile academic or work environment. Sexual harassment maySexualHarassment Yale University statement on sexual harassment Sexual harassment is antithetical of University policy and may result in serious disciplinary action. Sexual harassment consists of nonconsen

260

Adolescent Sexual Behavior and Sexual Education in the United States  

Microsoft Academic Search

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

Therese B Orbea

2010-01-01

261

Sexual and aggressive motives in sexually aggressive college males  

Microsoft Academic Search

The relative contributions to sexual aggression of general sexual and aggressive motives and their respective inhibitory factors were compared. One hundred forty-three university males responded to self-report measures of sexual and aggressive drives, sex and hostility guilt, social desirability response bias, and history of coercive sexuality. With the effects of social desirability controlled, the only predictor of sexual aggression was

James F. Porter; Joseph W. Critelli; Catherine S. K. Tang

1992-01-01

262

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

263

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

264

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

265

Grid'5000 for high-quality reproducible research Lucas Nussbaum  

E-print Network

Grid'5000 for high-quality reproducible research Lucas Nussbaum lucas.nussbaum@loria.fr Grid'5000 Lucas Nussbaum Grid'5000 for high-quality reproducible research 1 / 28 hal-01011403,version1-23Jun2014, on a scientific instrument Often a mix of both: In Physics In Computer Science Lucas Nussbaum Grid'5000 for high

Paris-Sud XI, Université de

266

Ruggedness and reproducibility of the MBEC biofilm disinfectant efficacy test  

E-print Network

Ruggedness and reproducibility of the MBEC biofilm disinfectant efficacy test A.E. Parker a,b, , D.K. Walker a , D.M. Goeres a , N. Allan c , M.E. Olson c , A. Omar c a Center for Biofilm Engineering April 2014 Available online 9 May 2014 Keywords: Biofilm Ruggedness Reproducibility The MBECTM

Parker, Albert E.

267

Interobserver reproducibility of Gleason grading of prostatic carcinoma: Urologic pathologists  

Microsoft Academic Search

Gleason grading is now the most widely used grading system for prostatic carcinoma in the United States. However, there are only a few studies of the interobserver reproducibility of this system, and no extensive study of interobserver reproducibility among a large number of experienced urologic pathologists exists. Forty-six needle biopsies containing prostatic carcinoma were assigned Gleason scores by 10 urologic

William C Allsbrook; Kathy A Mangold; Maribeth H Johnson; Mahul B Amin; David G Bostwick; Peter A Humphrey; Edward C Jones; Victor E Reuter; Wael Sakr; Isabell A Sesterhenn; Patricia Troncoso; Thomas M Wheeler; Jonathan I Epstein

2001-01-01

268

Reproducing kernel element method. Part I: Theoretical formulation  

E-print Network

Reproducing kernel element method. Part I: Theoretical formulation Wing Kam Liu a,*, Weimin Han b, collectively called the reproducing kernel element method (RKEM). The central idea in the development of the new method is to combine the strengths of both finite element methods (FEM) and meshfree methods. Two

Li, Shaofan

269

Reproducing kernel element method. Part IV: Globally compatible Cn  

E-print Network

Reproducing kernel element method. Part IV: Globally compatible Cn ðn P 1� triangular hierarchy Cn ðX� triangular element hierarchy is constructed in the framework of reproducing kernel element conforming element can be made arbitrarily high ðn P 1�. The triangle interpolation field can interpolate

Li, Shaofan

270

Evolution of sexuality: biology and behavior  

PubMed Central

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

2005-01-01

271

Evolution and human sexuality.  

PubMed

The aim of this review is to put core features of human sexuality in an evolutionary light. Toward that end, I address five topics concerning the evolution of human sexuality. First, I address theoretical foundations, including recent critiques and developments. While much traces back to Darwin and his view of sexual selection, more recent work helps refine the theoretical bases to sex differences and life history allocations to mating effort. Second, I consider central models attempting to specify the phylogenetic details regarding how hominin sexuality might have changed, with most of those models honing in on transitions from a possible chimpanzee-like ancestor to the slightly polygynous and long-term bonded sociosexual partnerships observed among most recently studied hunter-gatherers. Third, I address recent genetic and physiological data contributing to a refined understanding of human sexuality. As examples, the availability of rapidly increasing genomic information aids comparative approaches to discern signals of selection in sexuality-related phenotypes, and neuroendocrine studies of human responses to sexual stimuli provide insight into homologous and derived mechanisms. Fourth, I consider some of the most recent, large, and rigorous studies of human sexuality. These provide insights into sexual behavior across other national samples and on the Internet. Fifth, I discuss the relevance of a life course perspective to understanding the evolution of human sexuality. Most research on the evolution of human sexuality focuses on young adults. Yet humans are sexual beings from gestation to death, albeit in different ways across the life course, and in ways that can be theoretically couched within life history theory. PMID:24151100

Gray, Peter B

2013-12-01

272

Sexual morality of Christianity.  

PubMed

After discussing the origin of religion, functions of religion, and the construction of meaning by religion, the author focuses on the connection between religion and anxiety. The permanent anxiety in religion is determined by guilt feelings that arise for example from the violation of norms in the area of sexuality. In a religion at enmity with sexuality, such as Christianity, the satisfaction of sexual desires is considered bad and sinful; the permanent production of anxiety and a guilty conscience are the result of it. Christian sexual suppression leads to the propagation of asceticism as the taming of corrupt sensuality that only religious virtuosi can maintain. One result of asceticism is celibacy, although passages from the Bible demand monogamy for bishops without prohibiting celibacy. In Catholicism, celibacy institutionalizes the enmity with sexuality and causes a permanent depreciation of real sexuality in favor of one projected onto the mother church and the Virgin Mary. A further consequence of asceticism is the reduction of sexuality to reproduction. In the section about the factual consequences of Christian sexual morality, the author connects sexual instinctual gratification with religious affiliation on the basis of an analysis of the sexual behavior of Germans. The weekly frequency rate of sexual intercourse amounts to 3.1 with male and female nondenominationals, 2.6 with Protestants, and 2.3 with Catholics; 39% of nondenominational men, 20% of Protestant men, and 12% of Catholic men in Germany use condoms. The connection of religion and aggression is empirically significant as well. The religiously most active men feel more inclined to use aggression to reach sexual goals than religiously indifferent ones. PMID:9611690

Runkel, G

1998-01-01

273

Preventing Sexually Transmitted Diseases  

PubMed Central

The discouraging results of early efforts to educate the public about sexually transmitted diseases indicated that the goals of STD preventive action must be longer term and must change attitudes and behaviour as well as educate. They must also avoid an ostrich mentality about the sexual involvement of young people. This article examines more recent approaches to teaching about sexuality in general and STD prevention in particular. PMID:21221351

Kieren, Dianne; Cumming, Ceinwen E.; Cumming, David C.

1992-01-01

274

Impaired Sexual Function  

Microsoft Academic Search

The incidence of impaired sexual function in adults with Parkinson’s disease (PD) is greater than in the general population.\\u000a Studies have examined different aspects of sexual function among adults with PD and their partners. Comparison groups have\\u000a included healthy adults matched for age and gender, as well as age-matched controls with chronic, non-neurological disease\\u000a with motor impairment. Impaired sexual function

Cheryl Waters; Janice Smolowitz

275

[Depressive symptoms and sexuality].  

PubMed

The mutually reinforcing dyad of depressive symptoms and erectile dysfunction is scientifically established. The cure of depression improves sexual dysfunction (SD) and the treatment of SD induces improvement of depression. Most of anti-depressants induce negative sexual side effects that lead to non-compliance of these treatments. The knowledge of interrelation between depression, anti-depressants and sexuality is of great importance in clinical practice. PMID:25148948

Porto, Robert

2014-10-01

276

[Sexuality and urological diseases].  

PubMed

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

Droupy, Stéphane

2014-10-01

277

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

E-print Network

with a History of Childhood Sexual Abuse Alessandra H. Rellini · Cindy M. Meston Received: 30 June 2009 / Revised to the mediating effects of sexual self-schemas on the sexual difficulties of women with a history of childhood sexual abuse (CSA). The following study adds to the extant literature by investigating (1) sexual

Meston, Cindy

278

Prime time sexual harrassment.  

PubMed

This study explores the explicit and implicit messages of sexual harassment that viewers receive when viewing prime-time television in the US. A content analysis of 48 hours of prime-time television reveals that sexual harassment on television is both highly visible and invisible. Sexual harassment is rendered visible simply by its prominence in these programs. Incidents involving quid-pro-quo harassment and environmental harassment occur with regularity on television. Furthermore, about 84% of the shows studied contained at least one incident of sexual harassment; yet these acts of sexual harassment remained largely invisible because none of the behaviors were labeled as sexual harassment. These incidents are presented in humorous ways, and victims are generally unharmed and very effective at ending the harassment. Although such programs may actually reflect the reality of many women's lives in terms of prevalence of sexual harassment, they perpetuate several myths about sexual harassment, such as that sexual harassment is not serious and that victims should be able to handle the situations themselves. PMID:12294811

Grauerholz, E; King, A

1997-04-01

279

About Sexually Transmitted Diseases (STDs)  

MedlinePLUS

KidsHealth > Teens > Sexual Health > STDs & Other Infections > About Sexually Transmitted Diseases (STDs) Print A A A Text Size What's ... STDs Spread Preventing and Treating STDs More Information Sexually transmitted diseases (STDs) are infectious diseases that spread from person ...

280

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

Microsoft Academic Search

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

Thomas N. Sherratt; Mark R. Forbes

2001-01-01

281

Multivariate sexual selection in a rapidly evolving speciation phenotype.  

PubMed

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

Oh, Kevin P; Shaw, Kerry L

2013-06-22

282

Effect of Initial Conditions on Reproducibility of Scientific Research  

PubMed Central

Background: It is estimated that about half of currently published research cannot be reproduced. Many reasons have been offered as explanations for failure to reproduce scientific research findings- from fraud to the issues related to design, conduct, analysis, or publishing scientific research. We also postulate a sensitive dependency on initial conditions by which small changes can result in the large differences in the research findings when attempted to be reproduced at later times. Methods: We employed a simple logistic regression equation to model the effect of covariates on the initial study findings. We then fed the input from the logistic equation into a logistic map function to model stability of the results in repeated experiments over time. We illustrate the approach by modeling effects of different factors on the choice of correct treatment. Results: We found that reproducibility of the study findings depended both on the initial values of all independent variables and the rate of change in the baseline conditions, the latter being more important. When the changes in the baseline conditions vary by about 3.5 to about 4 in between experiments, no research findings could be reproduced. However, when the rate of change between the experiments is ?2.5 the results become highly predictable between the experiments. Conclusions: Many results cannot be reproduced because of the changes in the initial conditions between the experiments. Better control of the baseline conditions in-between the experiments may help improve reproducibility of scientific findings. PMID:25132705

Djulbegovic, Benjamin; Hozo, Iztok

2014-01-01

283

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

284

Role of sexual selection in speciation in Drosophila.  

PubMed

The power of sexual selection to drive changes in the mate recognition system through divergence in sexually selected traits gives it the potential to be a potent force in speciation. To know how sexual selection can bring such type of divergence in the genus Drosophila, comparative studies based on intra- and inter-sexual selection are documented in this review. The studies provide evidence that both mate choice and male-male competition can cause selection of trait and preference which thereby leads to divergence among species. In the case of intrasexual selection, various kinds of signals play significant role in affecting the species mate recognition system and hence causing divergence between the species. However, intrasexual selection can bring the intraspecific divergence at the level of pre- and post-copulatory stage. This has been better explained through Hawaiian Drosophila which has been suggested a wonderful model system in explaining the events of speciation via sexual selection. This is due to their elaborate mating displays and some kind of ethological isolation persisting among them. Similarly, the genetic basis of sexually selected variations can provide yet another path in understanding the speciation genetics via sexual selection more closely. PMID:24362558

Singh, Akanksha; Singh, Bashisth N

2014-02-01

285

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. PMID:18426753

Kunte, Krushnamegh

2008-01-01

286

Measurement of Force Balance Repeatability and Reproducibility in the NTF  

NASA Technical Reports Server (NTRS)

A recently published statistical approach for measuring and evaluating wind tunnel force balance repeatability and reproducibility is applied to three check standard tests in the National Transonic Facility at NASA Langley Research Center. Two different airframe models and force balances were used. The short-term repeatability and within-test reproducibility are separately estimated and correlations with tunnel parameters are carried out. Conjectures are presented for the development of scaling laws for predicting the repeatability and reproducibility of other force balance tests in the tunnel.

Hemsch, M. J.; Tuttle, D. G.; Houlden, H. P.; Graham, A. B.

2004-01-01

287

Sexual Harassment in Schools.  

ERIC Educational Resources Information Center

Students and employees are legally protected against sexual harassment, regardless of the perpetrator's age or status. Although caution is needed when responding to complaints, school leaders should avoid making backroom deals with staff members accused of molestation or improper sexual conduct. All school community members need information and…

Stein, Nan D.

1993-01-01

288

Sexual Orientation (For Parents)  

MedlinePLUS

... Kids For Parents MORE ON THIS TOPIC A Parent's Guide to Surviving the Teen Years Understanding Early Sexual Development STDs Questions and Answers About Sex Teaching Your Child Tolerance Transgender People Am I in a Healthy Relationship? Transgender People Love and Romance Sexual Attraction and ...

289

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

290

Sexual Harassment Protocol.  

ERIC Educational Resources Information Center

This document spells out policy regarding sexual harassment in the Connecticut vocational-technical school system that was developed by the Connecticut State Department of Education, the Connecticut Division of Vocational, Technical, and Adult Education, and the Connecticut Women's Education and Legal Fund, Inc. The introduction calls sexual…

Connecticut Women's Education and Legal Fund, Hartford.

291

Sexing Geography, Teaching Sexualities.  

ERIC Educational Resources Information Center

Draws on experiences as a straight feminist geographer to address questions regarding teaching sexualities in geography. Looks at "sexing" and "queering" geography curricula at the college level; discusses strategies to make universities and classrooms less heterosexist and lesbo/homophobic; and discusses dilemmas of disclosing sexuality in the…

England, Kim

1999-01-01

292

Evaluating Sexuality Education Curriculums.  

ERIC Educational Resources Information Center

In contrast to studies of abstinence-only programs, studies of abstinence-plus curricula indicate that students do not increase sexual activity. Parents, teachers, and administrators should evaluate all sexuality education programs according to three important criteria: credibility of training materials, curriculum content, and curriculum…

Wiley, David C.; Terlosky, Beverly

2000-01-01

293

Sexuality and Menopause  

Microsoft Academic Search

Postmenopausal sexuoerotic health is multivariately determined by both intrinsic and extrinsic variables, some of which may predate the menopause. In a pilot study of 20 postmenopausal women, even when deterioration in sexual well-being was anticipated beforehand, it did not inevitably materialize, but if it did so, it was not inevitably correlated with diminished partner availability. Postmenopausal ratings of eroto-sexual ideation,

James Frock; John Money

1992-01-01

294

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

295

Sexual Harassment in Nursing.  

ERIC Educational Resources Information Center

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

Duldt, Bonnie W.

1982-01-01

296

The Sexual Genogram.  

ERIC Educational Resources Information Center

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

Hof, Larry; Berman, Ellen

1986-01-01

297

Female Sexuality: An Enigma.  

ERIC Educational Resources Information Center

Describes constructions of sexuality that have occurred within social context in which language, culture, and behavior interact to reinforce male power. Against backdrop of these patriarchal examples of female sexual expression and experience, discusses difficulties of female clients. Addresses critical counseling concerns in terms of contextual…

Daniluk, Judith

1991-01-01

298

Men and Sexual Trauma  

MedlinePLUS

... Adult male survivors of childhood sexual abuse. Counseling Psychology Quarterly, 8, 233-241. Garnefski, N., & Diekstra, R. F. W. (1997). Child sexual abuse and emotional and behavioral problems in adolescence: Gender differences. Journal of the American Academy of Child & Adolescent Psychiatry, 36, ...

299

Sexually Transmitted Diseases (STDs)  

MedlinePLUS

... JavaScript on. Read more information on enabling JavaScript. Sexually Transmitted Diseases (STDs) Top Banner Content Area Skip Content Marketing ... of Two Herpes Viruses —Jan. 5, 2012 All Sexually Transmitted Diseases News Releases News From NIAID-Supported Institutions Last ...

300

Properties of galaxies reproduced by a hydrodynamic simulation  

E-print Network

Previous simulations of the growth of cosmic structures have broadly reproduced the ‘cosmic web’ of galaxies that we see in the Universe, but failed to create a mixed population of elliptical and spiral galaxies, because ...

Genel, S.

301

8. Historic American Buildings Survey Reproduced from the collections of ...  

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

8. Historic American Buildings Survey Reproduced from the collections of the Library of Congress, Accession No. 45041 Geographical File ('Nantucket, Mass.') Division of Prints and Photographs c. 1880 - Jethro Coffin House, Sunset Hill, Nantucket, Nantucket County, MA

302

10 CFR 95.43 - Authority to reproduce.  

Code of Federal Regulations, 2010 CFR

...Authority to reproduce. 95.43 Section 95.43 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) FACILITY SECURITY...of the procedures for classified reproduction. The use of technology that prevents, discourages, or detects the...

2010-01-01

303

Multiresolution Reproducing Kernel Particle Method for Computational Fluid Dynamics  

E-print Network

Multiresolution Reproducing Kernel Particle Method for Computational Fluid Dynamics Wing Kam Liu (RKPM) is developed for computational fluid dynamics. An algorithm incorporating multiple scale adaptive in fluid dynamics. KEY WORDS: meshless kernel particle method, multiresolution analysis, wavelets

Liu, Wing Kam

304

Sexual Desire Disorders  

PubMed Central

Hypoactive sexual desire disorder (HSDD) and sexual aversion disorder (SAD) are an under-diagnosed group of disorders that affect men and women. Despite their prevalence, these two disorders are often not addressed by healthcare providers and patients due their private and awkward nature. As physicians, we need to move beyond our own unease in order to adequately address our patients’ sexual problems and implement appropriate treatment. Using the Sexual Response Cycle as the model of the physiological changes of humans during sexual stimulation and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition this article will review the current literature on the desire disorders focusing on prevalence, etiology, and treatment. PMID:19727285

Montgomery, Keith A.

2008-01-01

305

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

306

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

E-print Network

02215, USA Sexual dimorphism is ubiquitous in animals and can result from selection pressure on one the burden of parental care but where coevolution between parasitic cuckoos and their hosts also results with larger females in cuckoos with parental care to dimorphism with larger males in parasitic species

Krüger, Oliver

307

Sexual Selection and Sexual Dimorphism in the Harlequin Beetle Acrocinus longimanus  

Microsoft Academic Search

To investigate the causes of striking sexual dimorphism in the harlequin beetle (Acrocinus longimanus), we carried out a study of the behavior and morphology of two widely separated populations (in French Guiana and Panama). Males of this species possess greatly elongated forelegs which exhibit strong positive dometry with body size (elytra length). Males use their forelegs in fights with other

David W. Zeh; Jeanne A. Zeh; Gérard Tavakilian

308

Sources of variability in the reproducibility of food frequency questionnaires.  

PubMed

The reproducibility of food frequency questionnaires varies widely. Since reports of past intake are known to be biased toward the present and the forces of supply and demand affect what people eat at a given point in time, the questionnaire may capture an atypical snapshot of consumption rather than the intended view of unusual consumption. The consumption of regularly consumed foods is the same throughout the year. The consumption of these foods is likely to be highly reproducible at another point in time. The consumption of seasonally consumed foods, however, fluctuates throughout the year, and may have peaks in winter or summer or particular holidays. There may be no common denominator among these foods necessary for the purpose of assessing reproducibility. Therefore, questionnaires that contain a combination of regularly and seasonally consumed foods, will be likely to have problems with reproducibility, the variance depending upon the number of seasonally consumed foods in the questionnaire. This explanation for variability in reproducing food frequency questionnaires raises a question about the importance of assessing reproducibility as a way of evaluating the worth of questionnaires. Perhaps an improved method of collecting data for seasonal foods is what is really needed to improve the quality of data collected. PMID:9670173

Joachim, G

1998-01-01

309

The role of selection and gene flow in the evolution of sexual isolation in Timema walking sticks and other Orthopteroids  

Microsoft Academic Search

The formation of new species involves the evolution of barriers to gene exchange. One such barrier is sexual isolation, where divergent mate preferences prevent copulation between taxa. Sexual isolation can evolve via a number of processes, including natural selection, sexual selection, genetic drift, and reinforcing selection to avoid maladaptive hybridization. Conversely, gene flow between populations generally erodes the evolution of

P. Nosil

2005-01-01

310

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

311

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

312

Sexual selection accelerates signal evolution during speciation in birds  

PubMed Central

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

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

2013-01-01

313

Sexual selection accelerates signal evolution during speciation in birds.  

PubMed

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

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

2013-09-01

314

Life cycle of the multiarmed sea star Coscinasterias acutispina (Stimpson, 1862) in laboratory culture: sexual and asexual reproductive pathways.  

PubMed

The multiarmed sea star Coscinasterias acutispina generally has 7-10 arms and 2-5 madreporites. It is known to be able to reproduce by asexual fission, and we have previously observed that this species also has the ability to reproduce sexually; however, there has been no report until now of spawning in this species. We succeeded in establishing a long-term culture of juveniles produced by artificial fertilization. Twelve months after the completion of metamorphosis, three individuals had six arms of the same length and a madreporite. At this time, fission occurred in two of these individuals, while the remaining individual underwent fission four months later. Each sea star divided into two halves, provided with three arms each. Thereafter, four or five new arms and two or four madreporites were formed anew in each of the six daughter sea-stars, so that by 30 days after the first fission the number of arms and madreporites in each was similar to that in adults. A second fission occurred in four of these six individuals, four or five months after the first fission, and in three of them the plane of division was the same as that of the first fission. The original three individuals eventually proliferated to 12 by undergoing fission. All individuals had fully developed gonads by 1-3 months after the second fission. Some of them eventually spawned under laboratory culture, and the resulting larvae metamorphosed into juveniles. Our observations demonstrate that individuals of C. acutispina possess the potential for both sexual and asexual reproduction. PMID:21557653

Shibata, Daisuke; Hirano, Yoshiaki; Komatsu, Miéko

2011-05-01

315

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.  

E-print Network

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. #12;Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. #12;Reproduced with permission of the copyright owner. Further reproduction prohibited without

Brody, James P.

316

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.  

E-print Network

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. PR EVIEW #12;Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. PR EVIEW #12;Reproduced with permission of the copyright owner. Further reproduction

Coble, Theresa G.

317

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

PubMed Central

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

Hines, Melissa

2012-01-01

318

Post-copulatory sexual selection and sexual conflict in the evolution of male pregnancy.  

PubMed

Male pregnancy in seahorses, pipefishes and sea dragons (family Syngnathidae) represents a striking reproductive adaptation that has shaped the evolution of behaviour and morphology in this group of fishes. In many syngnathid species, males brood their offspring in a specialized pouch, which presumably evolved to facilitate male parental care. However, an unexplored possibility is that brood pouch evolution was partly shaped by parent-offspring or sexual conflict, processes that would result in trade-offs between current and future pregnancies. Here we report a controlled breeding experiment using the sexually dimorphic Gulf pipefish, Syngnathus scovelli, to test for post-copulatory sexual selection within broods and for trade-offs between successive male pregnancies as functions of female attractiveness. Offspring survivorship within a pregnancy was affected by the size of a male's mate, the number of eggs transferred and the male's sexual responsiveness. Significantly, we also found that embryo survivorship in a current pregnancy was negatively related to survivorship in the prior pregnancy, clearly demonstrating fitness trade-offs between broods. Overall, our data indicate that post-copulatory sexual selection and sexual conflict occur in Gulf pipefishes. The conflict seems to be mediated by a strategy of cryptic choice in which males increase rates of offspring abortion in pregnancies from unattractive mothers to retain resources for future reproductive opportunities. Hence, the male brood pouch of syngnathid fishes, which nurtures offspring, also seems to have an important role as an arbiter of conflict between the sexes. PMID:20237568

Paczolt, Kimberly A; Jones, Adam G

2010-03-18

319

Sexual conflict over parental care: a case study of shorebirds  

Microsoft Academic Search

Shorebirds provide excellent model organisms to study breeding system evolution. We argue that sexual conflict theory is a useful approach to understand breeding system evolution in general, and specifically in shorebirds. Here, we focus on two major questions: (1) why do species shift from biparental care to uniparental care, and (2) why do some species shift toward female-biased care whereas

Tamas Szekely; Andras Kosztolanyi; Clemens Kupper; Gavin H. Thomas

320

Sexual selection, germline mutation rate and sperm competition  

PubMed Central

Background An important component of sexual selection arises because females obtain viability benefits for their offspring from their mate choice. Females choosing extra-pair fertilization generally favor males with exaggerated secondary sexual characters, and extra-pair paternity increases the variance in male reproductive success. Furthermore, females are assumed to benefit from 'good genes' from extra-pair sires. How additive genetic variance in such viability genes is maintained despite strong directional selection remains an evolutionary enigma. We propose that sexual selection is associated with elevated mutation rates, changing the balance between mutation and selection, thereby increasing variance in fitness and hence the benefits to be obtained from good genes sexual selection. Two hypotheses may account for such elevated mutation: (1) Increased sperm production associated with sperm competition may increase mutation rate. (2) Mutator alleles increase mutation rates that are revealed by the expression of condition-dependent secondary sexual characters used by choosy females during their mate choice. M Petrie has independently developed the idea that mutator alleles may account for the maintenance of genetic variation in viability despite strong directional selection. Results A comparative study of birds revealed a positive correlation between mutation rate at minisatellite loci and extra-pair paternity, but not between mutation rate and relative testes mass which is a measure of relative sperm production. Minisatellite mutation rates were not related to longevity, suggesting a meiotic rather than a mitotic origin of mutations. Conclusion We found evidence of increased mutation rate in species with more intense sexual selection. Increased mutation was not associated with increased sperm production, and we suggest that species with intense sexual selection may maintain elevated mutation rates because sexual selection continuously benefits viability alleles expressed in condition-dependent characters. Sexual selection may increase mutational input, which in turn feeds back on sexual selection because of increased variance in viability traits. PMID:12702218

M?ller, AP; Cuervo, JJ

2003-01-01

321

Sexual reproduction of human fungal pathogens.  

PubMed

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

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

2014-08-01

322

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

323

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

324

Human Sexuality: Responsible Life Choices.  

ERIC Educational Resources Information Center

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

Ryder, Verdene; Smith, Peggy B.

325

Sexual Rights: Striking a Balance  

Microsoft Academic Search

Sexual rights, the first of the eight Montreal Declarations adopted by the World Association for Sexual Health (WAS), are grounded within existing international human rights treaties, covenants and conventions and contribute to achieving the Millennium Development Goals (United Nations, 2005). Despite their apparent contribution to sexual health, sexual rights are particularly contentious, challenged both by nations that do not share

Eleanor Maticka-Tyndale; Lisa Smylie

2008-01-01

326

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

327

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

2012-08-01

328

Immune defence, extra-pair paternity, and sexual selection in birds  

PubMed Central

Secondary sexual characters have been suggested to reliably reflect the ability of individuals to resist debilitating parasites, and females may gain direct or indirect fitness benefits from preferring the most extravagantly ornamented males. Extra-pair paternity provides an estimate of an important component of sexual selection in birds. Species with a high frequency of extra-pair paternity have a variance in realized reproductive success that is greater than the variance in apparent reproductive success, and extra-pair copulations and hence extra-pair paternity by females are often directly associated with the expression of male secondary sexual characters. If sexually dichromatic species have experienced a long period of antagonistic coevolution with their parasites, such species should have evolved larger immune defence organs than sexually monochromatic species. Bird species with sexual dichromatism had larger spleens for their body size than monochromatic species in a comparative analysis. Furthermore, species with a high frequency of extra-pair paternity were sexually dichromatic and had large spleens for their body size. These results are consistent with the hypothesis that females of dichromatic bird species seek extra-pair copulations to obtain indirect fitness benefits in terms of superior resistance of their offspring to virulent parasites.

M?ller, A. P.

1997-01-01

329

Sexual Dimorphism in Primate Aerobic Capacity: A Phylogenetic Test  

PubMed Central

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

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

2010-01-01

330

Sexual dimorphism in primate aerobic capacity: a phylogenetic test.  

PubMed

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 haematocrit 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 co-vary negatively with body mass. For the first two predictions, we used a phylogenetic paired t-test developed for this study. We found support for predictions (i) and (ii). For prediction (iii), however, we found a negative correlation between the degree of sexual selection and aerobic capacity, which was opposite to our prediction. Prediction (iv) was generally supported. We also investigated whether substrate use, basal metabolic rate and agility influenced physiological measures of oxygen transport, but we found only weak evidence for a correlation between RBC count and agility. PMID:20406346

Lindenfors, Patrik; Revell, L J; Nunn, C L

2010-06-01

331

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

332

Reproductive strategy, sexual development and attraction to facial characteristics.  

PubMed

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

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

2006-12-29

333

Reproductive strategy, sexual development and attraction to facial characteristics  

PubMed Central

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

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

2006-01-01

334

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. PMID:15255043

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

2004-01-01

335

The herring gull complex is not a ring species.  

PubMed

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. PMID:15255043

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

2004-05-01

336

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

337

Making neurophysiological data analysis reproducible: why and how?  

PubMed

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 replication since the early eighties to end with what is now called reproducible research in computational data analysis oriented fields like statistics and signal processing. Since efficient tools are instrumental for a routine implementation of these approaches, a description of some of the available ones is presented next. A toy example demonstrates then the use of two open source software programs for reproducible data analysis: the "Sweave family" and the org-mode of emacs. The former is bound to R while the latter can be used with R, Matlab, Python and many more "generalist" data processing software. Both solutions can be used with Unix-like, Windows and Mac families of operating systems. It is argued that neuroscientists could communicate much more efficiently their results by adopting the reproducible research paradigm from their lab books all the way to their articles, thesis and books. PMID:21986476

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

2012-01-01

338

Number of sexual partners and sexual assertiveness predict sexual victimization: do more partners equal more risk?  

PubMed

In previous studies, number of sexual partners and sexual assertiveness were examined as independent risk factors for sexual victimization among college women. Using a sample of 335 college women, this study examined the interaction of number of sexual partners and sexual assertiveness on verbal sexual coercion and rape. Approximately 32% of the sample reported unwanted sexual intercourse, 6.9% (n = 23) experienced verbal sexual coercion, 17.9% (n = 60) experienced rape, and 7.2% (n = 24) experienced both. As number of sexual partners increased, instances of verbal sexual coercion increased for women low in relational sexual assertiveness but not for women high in relational sexual assertiveness. A similar relationship was not found for rape. Among women who experienced both verbal sexual coercion and rape, increases in number of partners in the context of low refusal and relational assertiveness were associated with increases in verbal sexual coercion and rape. Findings suggest sexual assertiveness is related to fewer experiences of sexual coercion. PMID:22288095

Walker, Dave P; Messman-Moore, Terri L; Ward, Rose Marie

2011-01-01

339

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

ERIC Educational Resources Information Center

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

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

2009-01-01

340

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

E-print Network

with a History of Childhood Sexual Abuse Alessandra H. Rellini · Cindy M. Meston Received: 30 June 2009 / Revised access at Springerlink.com Abstract Accumulating evidence points to the mediating effects of sexual self-schemas on the sexual difficulties of women with a history of childhood sexual abuse (CSA). The following study adds

Meston, Cindy

341

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. PMID:23919152

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

2013-01-01

342

Sexual selection and speciation in field crickets  

PubMed Central

Recent theoretical work has shown that sexual selection may cause speciation under a much wider range of conditions than previously supposed. There are, however, no empirical studies capable of simultaneously evaluating several key predictions that contrast this with other speciation models. We present data on male pulse rates and female phonotactic responses to pulse rates for the field cricket Gryllus texensis; pulse rate is the key feature distinguishing G. texensis from its cryptic sister species G. rubens. We show (i) genetic variation in male song and in female preference for song, (ii) a genetic correlation between the male trait and the female preference, and (iii) no character displacement in male song, female song recognition, female species-level song discrimination, or female song preference. Combined with previous work demonstrating a lack of hybrid inviability, these results suggest that divergent sexual selection may have caused speciation between these taxa. PMID:11121046

Gray, David A.; Cade, William H.

2000-01-01

343

What's In a Condom? – HIV and Sexual Politics in Japan  

Microsoft Academic Search

Utilizing a range of ethnographic data from anAIDS hotline, a women's shelter, a night club,AIDS campaigns, news articles, and interviewswith health bureaucrats, this paper exploresthe history of AIDS in Japan and the ways inwhich official practices reproduce systems ofdomination. This paper examines the officialcategories of ``foreign woman'' and``prostitution'' as discursive strategies ofcontainment, and argues that nationalistdiscourses and representations of sexuality

Elizabeth Miller

2002-01-01

344

Reproducing Kernel Functions: A general framework for Discrete Variable Representation  

E-print Network

Since its introduction, the Discrete Variable Representation (DVR) basis set has become an invaluable representation of state vectors and Hermitian operators in non-relativistic quantum dynamics and spectroscopy calculations. On the other hand reproducing kernel (positive definite) functions have been widely employed for a long time to a wide variety of disciplines: detection and estimation problems in signal processing; data analysis in statistics; generating observational models in machine learning; solving inverse problems in geophysics and tomography in general; and in quantum mechanics. In this article it was demonstrated that, starting with the axiomatic definition of DVR provided by Littlejohn [1], it is possible to show that the space upon which the projection operator, defined in ref [1], projects is a Reproducing Kernel Hilbert Space (RKHS) whose associated reproducing kernel function can be used to generate DVR points and their corresponding DVR functions on any domain manifold (curved or not). It ...

Mussa, Hamse

2014-01-01

345

A simple and reproducible method to obtain large numbers of axenic amastigotes of different Leishmania species  

Microsoft Academic Search

This work describes a simple method to yield large amounts of Leishmania amastigote-like forms in axenic cultures using promastigotes as the starting population. The method described induced extracellular amastigote transformation of Leishmania amazonensis (97%), Leishmania braziliensis (98%) and Leishmania chagasi (90%). The rounded parasites obtained in axenic cultures were morphologically similar, even at the ultrastructural level, to intracellular amastigotes. Moreover,

Márcia Teixeira; Regilene de Jesus Santos; Romina Barreto Sampaio; Lain Pontes-de-Carvalho; Washington L. dos-Santos

2002-01-01

346

Theories of Sexual Orientation.  

ERIC Educational Resources Information Center

Results indicated homosexuals, heterosexuals, and bisexuals did not differ within each sex on measures of masculinity and femininity. Strong support was obtained for the hypothesis that sexual orientation relates primarily to erotic fantasy orientation. (Author/DB)

Storms, Michael D.

1980-01-01

347

Child Sexual Abuse  

MedlinePLUS

... the child will develop serious problems as an adult. For additional information see Facts for Families : #4 The Depressed Child #5 Child Abuse #10 Teen Suicide #28 Responding to Child Sexual Abuse #62 Talking ...

348

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.

349

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 ...

350

Sexual Dysfunction and Infertility  

MedlinePLUS

... common type of sexual problem in men is erectile dysfunction, which is when your penis does not become or stay firm. Many medical conditions can cause erectile dysfunction: high blood pressure, diabetes, blood vessel diseases, surgery ...

351

Sexuality and Dementia  

MedlinePLUS

... A + A You are here Home Sexuality and Dementia Printer-friendly version Coping with Changes in Your ... said Jerry, who cared for his wife with dementia. At a recent conference of the Caregiver Resource ...

352

Sexual Problems in Men  

MedlinePLUS

Many men have sexual problems. They become more common as men age. Problems can include Erectile dysfunction Reduced or lost interest in sex Problems with ejaculation Low testosterone Stress, illness, medicines, or emotional problems may also ...

353

Sexual Health and Reproduction  

NSDL National Science Digital Library

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

Waldron, Ingrid

354

Sexuality and Down Syndrome  

MedlinePLUS

... to decision-making, cultural norms, peer pressures, relationships, social skills and opportunities. Positioning sexuality within the context of community life requires the development of personal values and adult responsibilities. An ideal curriculum will ensure that individuals with ...

355

Am I Sexually Normal?  

MedlinePLUS

... The problem with these familiar sources of sexual education is that comparisons can sometimes lead to feelings of inadequacy, even if you are otherwise satisfied with your sex life. You start to wonder if you are ...

356

Sexual abuse and sexual risk behaviors of minority women with sexually transmitted diseases.  

PubMed

The relationship between sexual abuse and sexually transmitted disease (STD) represents an important and underinvestigated context of domestic violence. This study examined the association between sexual abuse, sexual risk behaviors, and risk for reinfection and HIV among minority women with STD. Mexican American and African American women (n = 617) with active STD entered a randomized study of behavioral intervention to reduce STD recurrence. Each underwent questioning at entry regarding sexual abuse and sexual risk behaviors. Comparisons of these behaviors using chi-square, t tests, and logistic regression were made by history of sexual abuse. Sexually abused women were more likely to have lower incomes, earlier coitus, STD history, currently abusive partners, new sex partners, anal sex, and bleeding with sex, placing them at increased risk for STD reinfection and HIV. Due to this association with sexual risk behavior, assessment for sexual abuse is essential in programs focusing on STD/HIV prevention. PMID:11291429

Champion, J D; Shain, R N; Piper, J; Perdue, S T

2001-04-01

357

Multidimensional characterization of sexual minority adolescents' sexual safety strategies.  

PubMed

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

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

2013-10-01

358

Multidimensional Characterization of Sexual Minority Adolescents' Sexual Safety Strategies  

PubMed Central

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

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

2013-01-01

359

After breast cancer: sexual functioning of sexual minority survivors.  

PubMed

Research on sexual difficulties after cancer has neglected sexual minority women (SMW); for example, lesbian and bisexual women. Clinicians treating these women are therefore at a disadvantage as they lack information about sexual problems in this population. This study tested the hypothesis that SMW with breast cancer have poorer sexual function than SMW without breast cancer, distinguishing partnered from unpartnered women. Using convenience sample recruitment, we conducted a case-control study to compare survivors of breast cancers who are SMW, in other words, cases to controls, that is, SMW without cancer. Anonymous survey data were collected from 85 cases after they had completed active cancer treatment and 85 age- and partner-status matched controls with no history of any cancer. Participants' self-reported sexual frequency and sexual function measured by the Female Sexual Function Index were evaluated. Cases and controls did not differ in risk of sexual dysfunction or the level of overall sexual functioning; however, cases had lower sexual frequency and scored lower on desire and ability to reach orgasm, and higher on pain compared to controls. Results inform clinicians about sexual minority survivors' sexual domains affected by cancer. When discussing sexual problems and therapeutic options, sexual orientation should be ascertained. PMID:23730713

Boehmer, Ulrike; Ozonoff, Al; Timm, Alison; Winter, Michael; Potter, Jennifer

2014-01-01

360

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

361

Sexual Dysfunction Following Vulvectomy  

Microsoft Academic Search

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

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

2000-01-01

362

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

363

Next-generation sequencing data interpretation: enhancing reproducibility and accessibility.  

PubMed

Areas of life sciences research that were previously distant from each other in ideology, analysis practices and toolkits, such as microbial ecology and personalized medicine, have all embraced techniques that rely on next-generation sequencing instruments. Yet the capacity to generate the data greatly outpaces our ability to analyse it. Existing sequencing technologies are more mature and accessible than the methodologies that are available for individual researchers to move, store, analyse and present data in a fashion that is transparent and reproducible. Here we discuss currently pressing issues with analysis, interpretation, reproducibility and accessibility of these data, and we present promising solutions and venture into potential future developments. PMID:22898652

Nekrutenko, Anton; Taylor, James

2012-09-01

364

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

365

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

366

Sexual selection targets cetacean pelvic bones.  

PubMed

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

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

2014-11-01

367

The sexually active teenager.  

PubMed

This discussion of the sexually active teenager provides a statistical analysis of sexual behaviors and reviews developmental issues, contraceptive usage, adolescent pregnancy and its associated problems, and sex education. Major changes have occurred over the past 2 decades in sexual mores, contraceptive technology, the acceptance of single parent families, and the availability of induced abortion. In the US adolescent pregnancy and epidemic venereal disease have become major child health problems. It is important that the pediatrician, family practitioner, nurse practitioner, and mental health professional are aware of the magnitude of these problems and their potential areas for intervention. Various epidemiological studies of sexual behavior have documented an increase in the number of sexually active adolescents over the last decade. In a survey of metropolitan adolescents, Zelnik and Kantner found that the reported sexual activity among 15-19 years old adolescent girls increased from 30% in 1971 to 50% in 1979. Among never married white teenagers in this age group, statistics from 1971 indicated that 23% were sexually experienced, and this incidence increased to 42% in 1979. Much less is known about the sexual behavior of younger adolesents in the 11-14 year old range. The increased number of adolescents involved in premarital intercourse, coupled with the earlier age of menarche and delayed marriage, has increased the risk of premarital pregnancies. The number of adolescents between ages 15-19 experiencing a premarital pregnancy has increased significantly from 8.5% in 1971 to 16.2% in 1979, the most notable increase occurring among white teenagers. Among sexually experienced 15-19 years olds, 32.5% have experienced a premarital pregnancy. Sexual behavior among young adolescents is influenced by several variables, including maturation, personal values about premarital sex, inclination, and opportunity. There is an increasing tendency for adolescents to view sexual behavior as a matter of personal choice rather than a morality issue. Adolescents in all stages of development may delay obtaining adequate contraception. Denial of fertility is a common theme in early as well as late adolescence. The consistency and responsibility required for effective contraceptive use is not always compatible with the stage of adolescent development in which they have chosen to become sexually active. Use of effective contraception is often related to increasing sexual activity, increasing closeness of a relationship, a pregnancy scare because of a late or missing period, the positive influence of friends and family members or physicians, and/or the actual discovery of a contraceptive program. For adolescents access to contraceptives has been problematic and prescription contraception is frequently discontinued with continued sexual activity. Feelings of despair, worthlessness, and chronic school failure appear to be common factors among adolescents who choose to carry a pregnancy to term. Sex education courses should facilitate decision making about responsible sexual behavior. PMID:6833503

Emans, S J

1983-03-01

368

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

E-print Network

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

Lee, Herbie

369

Prolonged sexual abstinence after childbirth: gendered norms and perceived family health risks. Focus group discussions in a Tanzanian suburb  

PubMed Central

Background Prolonged sexual abstinence after childbirth is a socio-cultural practice with health implications, and is described in several African countries, including Tanzania. This study explored discourses on prolonged postpartum sexual abstinence in relation to family health after childbirth in low-income suburbs of Dar es Salaam, Tanzania. Methods Data for the discourse analysis were collected through focus group discussions with first-time mothers and fathers and their support people in Ilala, Dar es Salaam, Tanzania. Results In this setting, prolonged sexual abstinence intended at promoting child health was the dominant discourse in the period after childbirth. Sexual relations after childbirth involved the control of sexuality for ensuring family health and avoiding the social implications of non-adherence to sexual abstinence norms. Both abstinence and control were emphasised more with regard to women than to men. Although the traditional discourse on prolonged sexual abstinence for protecting child health was reproduced in Ilala, some modern aspects such as the use of condoms and other contraceptives prevailed in the discussion. Conclusion Discourses on sexuality after childbirth are instrumental in reproducing gender-power inequalities, with women being subjected to more restrictions and control than men are. Thus, interventions that create openness in discussing sexual relations and health-related matters after childbirth and mitigate gendered norms suppressing women and perpetuating harmful behaviours are needed. The involvement of males in the interventions would benefit men, women, and children through improving the gender relations that promote family health. PMID:23316932

2013-01-01

370

Education for sexuality.  

PubMed

Sex education provides a means to reduce the growing incidence of sexual abuse and of sexually transmitted diseases. Knowledge, which differs from permission, may protect. Sex education needs to provide factual information about anatomy and physiology and sexual development and responses. Further, it must guide young people towards healthy attitudes that develop concern and respect for others. This should enable them to make sound decisions about sexual behavior based on both knowledge and understanding of their own sexual identity and interpersonal relationships. The recent research shows that teenagers exposed to sex education are no more likely to engage in sexual intercourse than are other adolescents, and those who become sexually active are more likely to use a contraceptive method at 1st intercourse and are slightly less likely to experience premarital pregnancies. The nonuse of contraceptives is related to ignorance, lack of awareness of the consequences of sexual activity, and inaccessibility of suitable services. Consequently, young people need help to learn about the risks of pregnancy, how to avoid unwanted pregnancy, and where to go for counseling and services before they become sexually active. The provision of contraceptives must be made to meet the needs of adolescents. Formal sex education should be given in schools only with parental knowledge and cooperation. Youth leaders can influence young people positively by teaching about health and hygiene and promoting responsible attitudes toward sex and religion. Doctors and nurses have a unique opportunity to provide counseling throughout their patients' lives. The Department of Health (Capetown, South Africa) has appointed 445 nurses who oversee the youth program. They give sex education at schools, teaching colleges, youth camps, and at clinics. They also provide individual and group counseling for never pregnant, pregnant, and parent adolescents and their parents and partners at 8 youth health centers and existing family planning clinics. The Family Planning Association provides sex education at schools and teaching colleges and for parent teachers association groups and youth groups as well as church leaders and business executives. It is essential to promote honest communication with regard to sexuality and reproductive health care. PMID:3380143

Sapire, K E

1988-03-01

371

[Contraception and sexuality].  

PubMed

Earlier age at menarche, a longer reproductive life, and fewer desired births have been factors in the increasing importance of contraception in the life of women and couples. This work assesses the optimal contraceptive methods for different physiological phases of affective and sexual life and for various sexual problems. Contraception should prevent pregnancy, not promote sexually transmitted diseases and disorders of the genital tract, and preserve future fertility. The 1st gynecological consultation, even for very young girls, has 3 main objectives: detecting anomalies of the genital tract, ensuring that no physiological problems will arise in the 1st intercourse, and providing contraception if it will be needed in the relatively near future. The physician should speak directly to the young patient instead of to her mother. Hormonal contraception is preferred for adolescents with regular sexual activity, but for the majority who have episodic and irregular sexual relations other methods may be preferable. Condoms provide some protection against sexually transmitted diseases but require cooperation from the male partner. Vaginal sponges which can be left in place for 24 hours are easier to use than other vaginal methods. The "morning after" pill is available in case of unprotected coitus. The unplanned and unstable sexuality of adolescents is increasingly followed by a period of regular and continuous premarital sexual relations requiring reliable and continuous contraception. The pill remains the best choice for its efficacy, tolerance, and safety. Various formulations are available in case of contraindications to the classic combined pill. IUDs should be formally contraindicated because of the possibility of extrauterine pregnancy or salpingitis. Mechanical methods can be used for short periods but should not replace a more effective method on a permanent basis. The IUD may be a good choice for women who have completed their families. Oral contraceptives may be continued for premenopausal women without other cardiovascular risk factors. High dose progestins derived from 17 hydroxyprogesterone are recommended in case of luteal insufficiency. Premenopausal women whose sexual relations have become less frequent may prefer IUDs, local methods, or tubal ligation. Sexual difficulties of couples should be considered in selecting a method. Frigid women do not tolerate contraception well because fear of pregnancy is their excuse for avoiding sex. IUDs may be more satisfactory than pills in such cases because they do not require daily action. Pills may be the best choice in cases of premature ejaculation or impotence. PMID:12342527

Kahn-nathan, J

1987-01-01

372

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

373

Reeve-Irvine Research Center Replication and Reproducibility in  

E-print Network

with a minimum of variability in surgery, animal care, outcome evaluation and cellular analyses, Promptly report, clinical testing. If studies are NOT reproducible, this could save $millions that would otherwise be spent deficit levels. Publishing negative results is doable and generally well- received by the field. Slide

374

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

375

Ruggedness and reproducibility of the MBEC biofilm disinfectant efficacy test.  

PubMed

The MBEC™ Physiology & Genetics Assay recently became the first approved ASTM standardized biofilm disinfectant efficacy test method. This report summarizes the results of the standardization process using Pseudomonas aeruginosa biofilms. Initial ruggedness testing of the MBEC method suggests that the assay is rugged (i.e., insensitive) to small changes to the protocol with respect to 4 factors: incubation time of the bacteria (when varied from 16 to 18h), treatment temperature (20-24°C), sonication duration (25-35min), and sonication power (130-480W). In order to assess the repeatability of MBEC results across multiple tests in the same laboratory and the reproducibility across multiple labs, an 8-lab study was conducted in which 8 concentrations of each of 3 disinfectants (a non-chlorine oxidizer, a phenolic, and a quaternary ammonium compound) were applied to biofilms using the MBEC method. The repeatability and reproducibility of the untreated control biofilms were acceptable, as indicated by small repeatability and reproducibility standard deviations (SD) (0.33 and 0.67 log10(CFU/mm(2)), respectively). The repeatability SDs of the biofilm log reductions after application of the 24 concentration and disinfectant combinations ranged from 0.22 to 1.61, and the reproducibility SDs ranged from 0.27 to 1.70. In addition, for each of the 3 disinfectant types considered, the assay was statistically significantly responsive to the increasing treatment concentrations. PMID:24815513

Parker, A E; Walker, D K; Goeres, D M; Allan, N; Olson, M E; Omar, A

2014-07-01

376

Relative Validity and Reproducibility of a French Dietary History Questionnaire  

E-print Network

Relative Validity and Reproducibility of a French Dietary History Questionnaire Marti J Van Liere1, 94805 Villejuif Cedex, France, 2 Department of Psychology, Brooklyn College of CUNY, Brooklyn, NY 11120 05, France. Background. A self-administered dietary history questionnaire, especially developed

Paris-Sud XI, Université de

377

Female Anatomy Lecture outline Human Reproduc.ve  

E-print Network

9/9/12 1 Female Anatomy Lecture outline Human Reproduc.ve Anatomy A. Pelvic Female Anatomy A. External Genitalia B. Uterus, Ovaries & Oviducts C. Breasts #12 to outside Internal organs associated with female system: #12;9/9/12 6 Vagina- more a potential space than

Dever, Jennifer A.

378

A simple and reproducible breast cancer prognostic test  

PubMed Central

Background A small number of prognostic and predictive tests based on gene expression are currently offered as reference laboratory tests. In contrast to such success stories, a number of flaws and errors have recently been identified in other genomic-based predictors and the success rate for developing clinically useful genomic signatures is low. These errors have led to widespread concerns about the protocols for conducting and reporting of computational research. As a result, a need has emerged for a template for reproducible development of genomic signatures that incorporates full transparency, data sharing and statistical robustness. Results Here we present the first fully reproducible analysis of the data used to train and test MammaPrint, an FDA-cleared prognostic test for breast cancer based on a 70-gene expression signature. We provide all the software and documentation necessary for researchers to build and evaluate genomic classifiers based on these data. As an example of the utility of this reproducible research resource, we develop a simple prognostic classifier that uses only 16 genes from the MammaPrint signature and is equally accurate in predicting 5-year disease free survival. Conclusions Our study provides a prototypic example for reproducible development of computational algorithms for learning prognostic biomarkers in the era of personalized medicine. PMID:23682826

2013-01-01

379

Reproducibility of pulmonary function tests under laboratory and field conditions  

Microsoft Academic Search

The reproducibility of pulmonary function tests in the laboratory and in a mobile field survey vehicle has been studied. Groups of laboratory workers were studied at base and a random sample of 38 coalminers was examined in the mobile laboratory. The intra-subject variability of some newer tests of lung function, including closing volume and maximum flow at low lung volumes,

R G Love; M D Attfield; K D Isles

1980-01-01

380

Reproducible SERRS from structured gold surfacesw Sumeet Mahajan,a  

E-print Network

(R)S has been carried out using electrochemically-roughened silver electrodes and colloidal silver for the first time on electrodeposited gold films templated with colloidal spheres and demonstrate for fabricating reproducible substrates for SER(R)S. Amongst these, vapour- deposited silver films17 and silver

Steiner, Ullrich

381

RESEARCH ARTICLE Open Access Validity and reproducibility of the Physical  

E-print Network

RESEARCH ARTICLE Open Access Validity and reproducibility of the Physical Activity Scale for the Elderly (PASE) questionnaire for the measurement of the physical activity level in patients after total the physical activity level of patients after total knee arthroplasty (TKA) is of particular concern

Boyer, Edmond

382

Fast, Accurate, and Reproducible Live-Wire Boundary Extraction  

Microsoft Academic Search

We present an interactive tool for efficient, accurate, and reproducible boundary extraction which requires minimal user input with a mouse. Optimal boundaries are computed and selected at interactive rates as the user moves the mouse starting from a user-selected seed point. When the mouse position comes in proximity to an object edge, a “live-wire” boundary snaps to, and wraps around

William A. Barrett; Eric N. Mortensen

1996-01-01

383

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

384

Many loliginid squid populations depend entirely upon the reproduc-  

E-print Network

306 Many loliginid squid populations depend entirely upon the reproduc- tive output- mens, 2000; Semmens and Moltschani- wskyj, 2000). In California waters, Loligo opalescens (market squid, also known as the opalescent inshore squid [FAO]) live only 6-12 months (Butler et al., 1999) and die

385

The Disappearance of Moral Choice in Serially Reproduced Narratives  

E-print Network

person narrative Digital Object Identifier 10.4230/OASIcs.CMN.2013.36 1 Introduction The large questionThe Disappearance of Moral Choice in Serially Reproduced Narratives Fritz Breithaupt1 , Kevin M Sciences Johns Hopkins University Baltimore, MD, USA szorowi1@gmail.com Abstract How do narratives

Kruschke, John K.

386

Aging and Death in an Organism That Reproduces by Morphologically  

E-print Network

Aging and Death in an Organism That Reproduces by Morphologically Symmetric Division Eric J In macroscopic organisms, aging is often obvious; in single-celled organisms, where there is the greatest potential to identify the molecular mechanisms involved, identifying and quantifying aging is harder

Paris-Sud XI, Université de

387

Artificially reproduced image of earth photographed by UV camera  

NASA Technical Reports Server (NTRS)

A reproduction of a color enhancement of a picture photographed in far-ultraviolet light by Astronaut John W. Young, Apollo 16 commander, showing the Earth. Note this is an artificially reproduced image. The three auroral belts, the sunlit atmosphere and background stars are visible.

1972-01-01

388

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

2011-12-01

389

Audiovisual biofeedback improves diaphragm motion reproducibility in MRI  

PubMed Central

Purpose: In lung radiotherapy, variations in cycle-to-cycle breathing results in four-dimensional computed tomography imaging artifacts, leading to inaccurate beam coverage and tumor targeting. In previous studies, the effect of audiovisual (AV) biofeedback on the external respiratory signal reproducibility has been investigated but the internal anatomy motion has not been fully studied. The aim of this study is to test the hypothesis that AV biofeedback improves diaphragm motion reproducibility of internal anatomy using magnetic resonance imaging (MRI). Methods: To test the hypothesis 15 healthy human subjects were enrolled in an ethics-approved AV biofeedback study consisting of two imaging sessions spaced ?1 week apart. Within each session MR images were acquired under free breathing and AV biofeedback conditions. The respiratory signal to the AV biofeedback system utilized optical monitoring of an external marker placed on the abdomen. Synchronously, serial thoracic 2D MR images were obtained to measure the diaphragm motion using a fast gradient-recalled-echo MR pulse sequence in both coronal and sagittal planes. The improvement in the diaphragm motion reproducibility using the AV biofeedback system was quantified by comparing cycle-to-cycle variability in displacement, respiratory period, and baseline drift. Additionally, the variation in improvement between the two sessions was also quantified. Results: The average root mean square error (RMSE) of diaphragm cycle-to-cycle displacement was reduced from 2.6 mm with free breathing to 1.6 mm (38% reduction) with the implementation of AV biofeedback (p-value < 0.0001). The average RMSE of the respiratory period was reduced from 1.7 s with free breathing to 0.3 s (82% reduction) with AV biofeedback (p-value < 0.0001). Additionally, the average baseline drift obtained using a linear fit was reduced from 1.6 mm/min with free breathing to 0.9 mm/min (44% reduction) with AV biofeedback (p-value = 0.012). The diaphragm motion reproducibility improvements with AV biofeedback were consistent with the abdominal motion reproducibility that was observed from the external marker motion variation. Conclusions: This study was the first to investigate the potential of AV biofeedback to improve the motion reproducibility of internal anatomy using MRI. The study demonstrated the significant improvement in diaphragm motion reproducibility using AV biofeedback combined with MRI. This system can potentially provide clinically beneficial motion management of internal anatomy in MRI and radiotherapy. PMID:23127085

Kim, Taeho; Pollock, Sean; Lee, Danny; O'Brien, Ricky; Keall, Paul

2012-01-01

390

Sexual coercion and the misperception of sexual intent?  

PubMed Central

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

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

2010-01-01

391

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

Microsoft Academic Search

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

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

2011-01-01

392

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

393

Tract Specific Reproducibility of Tractography Based Morphology and Diffusion Metrics  

PubMed Central

Introduction The reproducibility of tractography is important to determine its sensitivity to pathological abnormalities. The reproducibility of tract morphology has not yet been systematically studied and the recently developed tractography contrast Tract Density Imaging (TDI) has not yet been assessed at the tract specific level. Materials and Methods Diffusion tensor imaging (DTI) and probabilistic constrained spherical deconvolution (CSD) tractography are performed twice in 9 healthy subjects. Tractography is based on common space seed and target regions and performed for several major white matter tracts. Tractograms are converted to tract segmentations and inter-session reproducibility of tract morphology is assessed using Dice similarity coefficient (DSC). The coefficient of variation (COV) and intraclass correlation coefficient (ICC) are calculated of the following tract metrics: fractional anisotropy (FA), apparent diffusion coefficient (ADC), volume, and TDI. Analyses are performed both for proximal (deep white matter) and extended (including subcortical white matter) tract segmentations. Results Proximal DSC values were 0.70–0.92. DSC values were 5–10% lower in extended compared to proximal segmentations. COV/ICC values of FA, ADC, volume and TDI were 1–4%/0.65–0.94, 2–4%/0.62–0.94, 3–22%/0.53–0.96 and 8–31%/0.48–0.70, respectively, with the lower COV and higher ICC values found in the proximal segmentations. Conclusion For all investigated metrics, reproducibility depended on the segmented tract. FA and ADC had relatively low COV and relatively high ICC, indicating clinical potential. Volume had higher COV but its moderate to high ICC values in most tracts still suggest subject-differentiating power. Tract TDI had high COV and relatively low ICC, which reflects unfavorable reproducibility. PMID:22485157

Besseling, Rene M. H.; Jansen, Jacobus F. A.; Overvliet, Geke M.; Vaessen, Maarten J.; Braakman, Hilde M. H.; Hofman, Paul A. M.; Aldenkamp, Albert P.; Backes, Walter H.

2012-01-01

394

Memories, fantasies and sexual victimization  

E-print Network

related to sexual abuse than would non-abused individuals. Freud's Views of Child Sexual Abuse Early in his career, Sigmund Freud addressed the memories of childhood sexual experiences that his clients had related to him. He believed them to be true... related to sexual abuse than would non-abused individuals. Freud's Views of Child Sexual Abuse Early in his career, Sigmund Freud addressed the memories of childhood sexual experiences that his clients had related to him. He believed them to be true...

Cockroft, Ronald Duane

2012-06-07

395

Is pedophilia a sexual orientation?  

PubMed

In this article, I address the question of whether pedophilia in men can be construed as a male sexual orientation, and the implications for thinking of it in this way for scientific research, clinical practice, and public policy. I begin by defining pedophilia and sexual orientation, and then compare pedophilia (as a potential sexual orientation with regard to age) to sexual orientations with regard to gender (heterosexuality, bisexuality, and homosexuality), on the bases of age of onset, correlations with sexual and romantic behavior, and stability over time. I conclude with comments about the potential social and legal implications of conceptualizing pedophilia as a type of sexual orientation in males. PMID:22218786

Seto, Michael C

2012-02-01

396

Diverse, continuous, and plastic sexual systems in barnacles.  

PubMed

Barnacles (Crustacea: Thoracica) show diverse sexual systems, including simultaneous hermaphroditism, androdioecy (hermaphrodites + males), and dioecy (females + males). When males occur, they are always much smaller (called dwarf males) than conspecific hermaphrodites or females. Ever since Darwin made this discovery, many scientists have been fascinated by such diversity. In this study, we provide an overview of (1) the diversity of sexual systems in barnacles, (2) the continuity between different sexual systems in some genera or species, and (3) the plasticity in sexual expression in several species. First, although most barnacles are hermaphroditic, both theoretical and empirical studies suggest that females and dwarf males tend to occur in species with small mating groups. Low sperm competition among hermaphrodites and little chance to act as a male are both associated with small group sizes and identified as the forces promoting the evolution of dwarf males and pure females, respectively. Second, in some groups of barnacles, the distinction between hermaphrodites and dwarf males is unclear because of the potential of dwarf males to become hermaphrodites. As many barnacle species tend toward protandric simultaneous hermaphroditism (develop male function first and then add female function without discarding male function), the dwarf males in such cases are best described as potential hermaphrodites that arrest growth and emphasize male function much earlier because of attachment to conspecifics. This is presumably advantageous in fertilizing the eggs of the host individuals. The distinction between hermaphrodites and females may also be obscured in some species. Third, sex allocation and penial morphology are plastic in some species. We also report the results of a transplanting experiment on small individuals of the pedunculate barnacle Octolasmis angulata, which suggests that individuals transplanted onto conspecifics developed longer and broader penises than did control individuals. Overall, the diversity, continuity, and plasticity in the sexual systems of barnacles are sources of important insights into the evolution and maintenance of the diversity of sexual systems. PMID:23589635

Yusa, Yoichi; Takemura, Mayuko; Sawada, Kota; Yamaguchi, Sachi

2013-10-01

397

25 CFR 700.561 - Sexual harassment.  

Code of Federal Regulations, 2010 CFR

...or rejection of sexual advances; —If the sexual conduct substantially...intimidating, hostile or offensive work environment. (c) Within...explicit coercive sexual behavior to control...engaging in sexual harassment....

2010-04-01

398

25 CFR 700.561 - Sexual harassment.  

Code of Federal Regulations, 2012 CFR

...or rejection of sexual advances; —If the sexual conduct substantially...intimidating, hostile or offensive work environment. (c) Within...explicit coercive sexual behavior to control...engaging in sexual harassment....

2012-04-01

399

25 CFR 700.561 - Sexual harassment.  

Code of Federal Regulations, 2013 CFR

...or rejection of sexual advances; —If the sexual conduct substantially...intimidating, hostile or offensive work environment. (c) Within...explicit coercive sexual behavior to control...engaging in sexual harassment....

2013-04-01

400

25 CFR 700.561 - Sexual harassment.  

...or rejection of sexual advances; —If the sexual conduct substantially...intimidating, hostile or offensive work environment. (c) Within...explicit coercive sexual behavior to control...engaging in sexual harassment....

2014-04-01

401

25 CFR 700.561 - Sexual harassment.  

Code of Federal Regulations, 2011 CFR

...or rejection of sexual advances; —If the sexual conduct substantially...intimidating, hostile or offensive work environment. (c) Within...explicit coercive sexual behavior to control...engaging in sexual harassment....

2011-04-01

402

Sexual Desire and the Female Sexual Function Index (FSFI): A Sexual Desire Cutpoint for Clinical Interpretation of the FSFI  

E-print Network

Sexual Desire and the Female Sexual Function Index (FSFI): A Sexual Desire Cutpoint for Clinical T Introduction. A validated cutpoint for the total Female Sexual Function Index scale score exists to classify, Rosen RC, Brewer JV, Meston CM, Brotto LA, Wiegel M, and Sand M. Sexual desire and the female sexual

Meston, Cindy

403

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

PubMed Central

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

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

2013-01-01

404

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

PubMed

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

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

2013-01-01

405

Sexual network position and risk of sexually transmitted infections  

Microsoft Academic Search

Objectives:A population-based sexual network study was used to identify sexual network structures associated with sexually transmitted infection (STI) risk, and to evaluate the degree to which the use of network-level data furthers the understanding of STI risk.Methods:Participants (n = 655) were from the baseline and 12-month follow-up waves of a 2001–2 population-based longitudinal study of sexual networks among urban African–American

C M Fichtenberg; S Q Muth; B Brown; N S Padian; T A Glass; J M Ellen

2009-01-01

406

Sexual Offense Adjudication and Sexual Recidivism among Juvenile Offenders  

Microsoft Academic Search

This study compares the recidivism patterns of a cohort of 249 juvenile sexual offenders and 1,780 non-sexual offending delinquents who were released from secured custody over a two and one half year period. The prevalence of sex offenders with new sexual offense charges during the 5 year follow-up period was 6.8%, compared to 5.7% for the non-sexual offenders, a non-significant

Michael F. Caldwell

2007-01-01

407

ORIGINAL PAPER Reported Sexual Desire Predicts Men's Preferences for Sexually  

E-print Network

in Women's Faces Benedict C. Jones · Anthony C. Little · Christopher D. Watkins · Lisa L. M. Welling · Lisa investigating the relationship between sexual desire and sexual attraction have found that heterosexual women desire is a generalized energizer of sexual attraction in heterosexual women (i.e., influences women

Little, Tony

408

The Sexuality Education Challenge: Promoting Healthy Sexuality in Young People.  

ERIC Educational Resources Information Center

This book offers the insights and perspectives of 39 sexuality educators. The collection of essays, full of theoretical considerations and practical implications, addresses the needs of those responsible for educating young people about sexuality and examines the major issues and concerns of sexuality education within the school setting.…

Drolet, Judy C., Ed.; Clark, Kay, Ed.

409

Sexual Coercion Content in 21 Sexuality Education Curricula.  

ERIC Educational Resources Information Center

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

Beyer, Christine E.; Ogletree, Roberta J.

1998-01-01

410

Child Sexual Behavior Inventory: Normative, Psychiatric, and Sexual Abuse Comparisons  

Microsoft Academic Search

A normative sample of 1,114 children was contrasted with a sample of 620 sexually abused children and 577 psychiatric outpatients on the Child Sexual Behavior Inventory (CSBI), a 38-item behavior checklist assessing sexual behavior in children 2 to 12 years old. The CSBI total score and each individual item differed significantly between the three groups after controlling for age, sex,

William N. Friedrich; Jennifer L. Fisher; Carrie Anne Dittner; Robert Acton; Lucy Berliner; Judy Butler; Linda Damon; W. Hobart Davies; Alison Gray; John Wright

2001-01-01

411

Association of Sexual Revictimization with Sexuality and Psychological Function  

ERIC Educational Resources Information Center

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

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

2006-01-01

412

Sexual Identity Development among Ethnic Sexual-Minority Male Youths.  

ERIC Educational Resources Information Center

This study explored how ethnicity influenced sexual identity development in 139 sexual-minority males. Findings demonstrated that participants, regardless of ethnicity, experienced most identity milestones at developmentally appropriate ages, had moderately low internalized homophobia, and became romantically and sexually involved with other males…

Dube, Eric M.; Savin-Williams, Ritch C.

1999-01-01

413

Definition of Sexual Harassment and Sexual Attention Experienced.  

ERIC Educational Resources Information Center

American women holding full-time jobs provided definitions of sexual harassment somewhat narrower than those used in previous studies. While sexual attention experienced was not related to subjects' definitions, having been harassed according to one's definition appeared to influence beliefs concerning the seriousness of sexual harassment in the…

Powell, Gary N.

1983-01-01

414

Independently Evolving Species in Asexual Bdelloid Rotifers  

Microsoft Academic Search

Asexuals are an important test case for theories of why species exist. If asexual clades displayed the same pattern of discrete variation as sexual clades, this would challenge the traditional view that sex is necessary for diversification into species. However, critical evidence has been lacking: all putative examples have involved organisms with recent or ongoing histories of recombination and have

Diego Fontaneto; Elisabeth A. Herniou; Chiara Boschetti; Manuela Caprioli; Giulio Melone; Claudia Ricci; Timothy G. Barraclough

2007-01-01

415

Recovery After Stroke: Redefining Sexuality  

MedlinePLUS

... is unlikely that a stroke will occur during sexual activity. Again, talk to your partner about this. It ... medicines. The medicines may increase your interest in sexual activity but also may have side effects that interfere ...

416

Sexual Harassment: Discrimination or Tort?  

E-print Network

distress caused by sexual harassment at work was an injuryCompensation and Sexual Harassment in the Work- place: Asexual harassment, the "conduct has the purpose or effect of unreasonably interfering with an individ- ual's work

Stromberg, Joanna

2003-01-01

417

Campus Climates for Sexual Minorities  

ERIC Educational Resources Information Center

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

Rankin, Susan R.

2005-01-01

418

Sexual Harassment in the Workplace.  

ERIC Educational Resources Information Center

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

Maypole, Donald E.; Skaine, Rosemarie

1983-01-01

419

Sexuality Attitudes of Black Adults.  

ERIC Educational Resources Information Center

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

Timberlake, Constance A.; Carpenter, Wayne D.

1990-01-01

420

Sexually Transmitted Diseases (STDs) Prevention  

MedlinePLUS

... STDs) Share Compartir Prevention How You Can Prevent Sexually Transmitted Diseases This page includes information about STD prevention, testing, ... 4636) TTY: (888) 232-6348 Contact CDC–INFO Sexually Transmitted Diseases Diseases & Related Conditions STDs & Infertility Other STDs Archive ...

421

SEXUALLY TRANSMITTED DISEASES SURVEILLANCE SYSTEM  

EPA Science Inventory

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

422

[Female sexuality and parenthood].  

PubMed

From the child conception to the early years of life, couples generally present less sexual activity. Parenthood constraints are a burden for the couple's relationships. Generally, persistent sexual difficulties six months after delivery, despite those generated by depression or altered health raise the question of an alteration in the quality of the couple's relationships and lack of satisfaction of the mother with her partner's involvement in family life. Numerous parameters can be implied, especially with persistent trouble of desire, such as fatigue, body image problems and libido lessening of the partner due to modifications of his status. Women who presented sexual difficulties before pregnancy remain the same. In all cases, appropriate information can avoid the intimacy's difficulties and contribute to maintain pleasure and intimacy even when vaginal penetration remains difficult. PMID:25262091

Colson, M-H

2014-10-01

423

Television and adolescent sexuality.  

PubMed

Existing studies of the sexual content of television programming and advertising and the effects of this content on adolescent viewers are reviewed. Content studies show that the frequency of sexual references have increased in the past decade and are increasingly explicit. Studies of the effects of this content, while scarce, suggest that adolescents who rely heavily on television for information about sexuality will have high standards of female beauty and will believe that premarital and extramarital intercourse with multiple partners is acceptable. They are unlikely to learn about the need for contraceptives as a form of protection against pregnancy or disease. Suggestions for future research and trends in television programming policies are explored. PMID:2307597

Brown, J D; Childers, K W; Waszak, C S

1990-01-01

424

Sexual Abuse Of Children  

PubMed Central

Increasing emphasis is being placed on the identification and management of sexual abuse in children. Family physicians have a role to play in identifying and treating these children. Some common myths about sexual abuse are that assaults are made mostly by strangers, that sexual abuse is rare, and that there's nothing wrong with sex between adults and children. Indicators in the child may be physical or behavioral. In the family, indicators include fathers with low self-esteem, poor relationships with wives, tendency to be domineering and restrictive, and mothers who are passive. Immediate and longterm intervention includes legal, protective and treatment components. The essential factors in successful intervention are belief in the child's disclosure; communication of that belief to the child; and immediate protection of the child and siblings. PMID:21286177

Herbert, Carol P.

1982-01-01

425

Sexual dimorphism, extrapair fertilizations, and operational sex ratio in great frigatebirds (Fregata minor)  

Microsoft Academic Search

Across taxa, the presence of sexual ornaments in one sex is usually correlated with disproportionately great parental effort by the other. Frigatebirds (Fregatidae) are sexually dimorphic, with males exhibiting morphological and behavioral ornaments, but males and females share in all aspects of parental effort. All other taxa in a clade of 237 species exhibit biparental care, but only frigatebirds exhibit

Donald C. Dearborn; Angela D. Anders; Patricia G. Parker

2001-01-01

426

The allometric pattern of sexually size dimorphic feather ornaments and factors affecting allometry  

Microsoft Academic Search

The static allometry of secondary sexual characters is currently subject to debate. While some studies suggest an almost universal positive allometry for such traits, but isometry or negative allometry for nonornamental traits, other studies maintain that any kind of allometric pattern is possible. Therefore, we investigated the allometry of sexually size dimorphic feather ornaments in 67 species of birds. We

J. J. CUERVO; A. P. MØLLER

2009-01-01

427

Implementation of a portable and reproducible parallel pseudorandom number generator  

SciTech Connect

The authors describe in detail the parallel implementation of a family of additive lagged-Fibonacci pseudorandom number generators. The theoretical structure of these generators is exploited to preserve their well-known randomness properties and to provide a parallel system in of distinct cycles. The algorithm presented here solves the reproducibility problem for a far larger class of parallel Monte Carlo applications than has been previously possible. In particular, Monte Carlo applications that undergo ``splitting`` can be coded to be reproducible, independent both of the number of processors and the execution order of the parallel processes. A library of portable C routines (available from the authors) that implements these ideas is also described.

Pryor, D.V.; Cuccaro, S.A.; Mascagni, M.; Robinson, M.L.

1994-12-31

428

Properties of galaxies reproduced by a hydrodynamic simulation.  

PubMed

Previous simulations of the growth of cosmic structures have broadly reproduced the 'cosmic web' of galaxies that we see in the Universe, but failed to create a mixed population of elliptical and spiral galaxies, because of numerical inaccuracies and incomplete physical models. Moreover, they were unable to track the small-scale evolution of gas and stars to the present epoch within a representative portion of the Universe. Here we report a simulation that starts 12 million years after the Big Bang, and traces 13 billion years of cosmic evolution with 12 billion resolution elements in a cube of 106.5?megaparsecs a side. It yields a reasonable population of ellipticals and spirals, reproduces the observed distribution of galaxies in clusters and characteristics of hydrogen on large scales, and at the same time matches the 'metal' and hydrogen content of galaxies on small scales. PMID:24805343

Vogelsberger, M; Genel, S; Springel, V; Torrey, P; Sijacki, D; Xu, D; Snyder, G; Bird, S; Nelson, D; Hernquist, L

2014-05-01

429

Reproducible analyses of microbial food for advanced life support systems.  

PubMed

The use of yeasts in Controlled Ecological Life Support Systems (CELSS) for microbial food regeneration in space required the accurate and reproducible analysis of intracellular carbohydrate and protein levels. The reproducible analysis of glycogen was a key element in estimating overall content of edibles in candidate yeast strains. Typical analytical methods for estimating glycogen in Saccharomyces were not found to be entirely applicable to other candidate strains. Rigorous cell lysis coupled with acid/base fractionation followed by specific enzymatic glycogen analyses were required to obtain accurate results in two strains of Candida. A profile of edible fractions of these strains was then determined. The suitability of yeasts as food sources in CELSS food production processes is discussed. PMID:11541295

Petersen, G R

1988-10-01

430

Properties of galaxies reproduced by a hydrodynamic simulation  

E-print Network

Previous simulations of the growth of cosmic structures have broadly reproduced the 'cosmic web' of galaxies that we see in the Universe, but failed to create a mixed population of elliptical and spiral galaxies due to numerical inaccuracies and incomplete physical models. Moreover, because of computational constraints, they were unable to track the small scale evolution of gas and stars to the present epoch within a representative portion of the Universe. Here we report a simulation that starts 12 million years after the Big Bang, and traces 13 billion years of cosmic evolution with 12 billion resolution elements in a volume of $(106.5\\,{\\rm Mpc})^3$. It yields a reasonable population of ellipticals and spirals, reproduces the distribution of galaxies in clusters and statistics of hydrogen on large scales, and at the same time the metal and hydrogen content of galaxies on small scales.

Vogelsberger, Mark; Springel, Volker; Torrey, Paul; Sijacki, Debora; Xu, Dandan; Snyder, Gregory F; Bird, Simeon; Nelson, Dylan; Hernquist, Lars

2014-01-01

431

Pressure stabilizer for reproducible picoinjection in droplet microfluidic systems.  

PubMed

Picoinjection is a promising technique to add reagents into pre-formed emulsion droplets on chip however, it is sensitive to pressure fluctuation, making stable operation of the picoinjector challenging. We present a chip architecture using a simple pressure stabilizer for consistent and highly reproducible picoinjection in multi-step biochemical assays with droplets. Incorporation of the stabilizer immediately upstream of a picoinjector or a combination of injectors greatly reduces pressure fluctuations enabling reproducible and effective picoinjection in systems where the pressure varies actively during operation. We demonstrate the effectiveness of the pressure stabilizer for an integrated platform for on-demand encapsulation of bacterial cells followed by picoinjection of reagents for lysing the encapsulated cells. The pressure stabilizer was also used for picoinjection of multiple displacement amplification (MDA) reagents to achieve genomic DNA amplification of lysed bacterial cells. PMID:25270338

Rhee, Minsoung; Light, Yooli K; Yilmaz, Suzan; Adams, Paul D; Saxena, Deepak; Meagher, Robert J; Singh, Anup K

2014-12-01

432

MASSIVE DATA, THE DIGITIZATION OF SCIENCE, AND REPRODUCIBILITY OF RESULTS  

SciTech Connect

As the scientific enterprise becomes increasingly computational and data-driven, the nature of the information communicated must change. Without inclusion of the code and data with published computational results, we are engendering a credibility crisis in science. Controversies such as ClimateGate, the microarray-based drug sensitivity clinical trials under investigation at Duke University, and retractions from prominent journals due to unverified code suggest the need for greater transparency in our computational science. In this talk I argue that the scientific method be restored to (1) a focus on error control as central to scientific communication and (2) complete communication of the underlying methodology producing the results, ie. reproducibility. I outline barriers to these goals based on recent survey work (Stodden 2010), and suggest solutions such as the “Reproducible Research Standard” (Stodden 2009), giving open licensing options designed to create an intellectual property framework for scientists consonant with longstanding scientific norms.

None

2010-07-02

433

Conceptualizing positive adolescent sexuality development  

Microsoft Academic Search

Is it possible to conceptualize adolescent sexuality in positive terms? Social control characterizes the cultural strategies\\u000a for managing both adolescence and sexuality, yet social movements have emerged in recent decades that have challenged historical\\u000a social norms and boundaries for both sexuality and adolescence. In this article, developing trends in adolescent sexual experience\\u000a (behavior, attitudes, and knowledge) are examined, as are

Stephen T. Russell

2005-01-01

434

Sexual Harassment: Identifying Risk Factors  

Microsoft Academic Search

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

Elizabeth A. O'Hare; William O'Donohue

1998-01-01

435

Reproducibility of the cold pressor test: studies in normal subjects  

Microsoft Academic Search

The reproducibility of the cold pressor test was studied in healthy subjects. A non-invasive method was utilized for estimating\\u000a beat-to-beat arterial blood pressure (BP) and heart rate (HR). The study population of 17 healthy volunteers consisted of\\u000a two groups. In the first group (Group 1, n=11), a 1-min test was performed three times during the same day. In the second

M. L. Fasano; T. Sand; A. O. Brubakk; P. Kruszewski; C. Bordini; O. Sjaastad

1996-01-01

436

Test-Retest Reproducibility Analysis of Lung CT Image Features.  

PubMed

Quantitative size, shape, and texture features derived from computed tomographic (CT) images may be useful as predictive, prognostic, or response biomarkers in non-small cell lung cancer (NSCLC). However, to be useful, such features must be reproducible, non-redundant, and have a large dynamic range. We developed a set of quantitative three-dimensional (3D) features to describe segmented tumors and evaluated their reproducibility to select features with high potential to have prognostic utility. Thirty-two patients with NSCLC were subjected to unenhanced thoracic CT scans acquired within 15 min of each other under an approved protocol. Primary lung cancer lesions were segmented using semi-automatic 3D region growing algorithms. Following segmentation, 219 quantitative 3D features were extracted from each lesion, corresponding to size, shape, and texture, including features in transformed spaces (laws, wavelets). The most informative features were selected using the concordance correlation coefficient across test-retest, the biological range and a feature independence measure. There were 66 (30.14 %) features with concordance correlation coefficient???0.90 across test-retest and acceptable dynamic range. Of these, 42 features were non-redundant after grouping features with R (2) Bet???0.95. These reproducible features were found to be predictive of radiological prognosis. The area under the curve (AUC) was 91 % for a size-based feature and 92 % for the texture features (runlength, laws). We tested the ability of image features to predict a radiological prognostic score on an independent NSCLC (39 adenocarcinoma) samples, the AUC for texture features (runlength emphasis, energy) was 0.84 while the conventional size-based features (volume, longest diameter) was 0.80. Test-retest and correlation analyses have identified non-redundant CT image features with both high intra-patient reproducibility and inter-patient biological range. Thus making the case that quantitative image features are informative and prognostic biomarkers for NSCLC. PMID:24990346

Balagurunathan, Yoganand; Kumar, Virendra; Gu, Yuhua; Kim, Jongphil; Wang, Hua; Liu, Ying; Goldgof, Dmitry B; Hall, Lawrence O; Korn, Rene; Zhao, Binsheng; Schwartz, Lawrence H; Basu, Satrajit; Eschrich, Steven; Gatenby, Robert A; Gillies, Robert J

2014-12-01

437

Fast, reproducible size-exclusion chromatography of biological macromolecules  

Microsoft Academic Search

The size-dependent separation of biological macromolecules can be effectively carried out using size-exclusion chromatography (SEC) on silica-based HPLC columns. For this technique to be successful, appropriate methods should be chosen. This paper presents practical guidelines for the development of reproducible SEC methods based upon optimized sample volume, flow-rate, column length and use of mobile phase conditions that reduce non-ideal SEC

R. D. Ricker; L. A. Sandoval

1996-01-01

438

Grading nuclear cataract: reproducibility and validity of a new method  

Microsoft Academic Search

AIMSTo assess the reproducibility and validity of a new instrument for grading nuclear cataract—the laser slit lamp, by comparison with an established method of lens grading—the Lens Opacities Classification System III (LOCS III).METHODS62 volunteers (113 eyes) were examined on two occasions. At each visit, a video image of the anterior segment was captured with the laser slit lamp and stored

Nigel F Hall; Philip Lempert; Rosaleen P Shier; Rahila Zakir; David Phillips

1999-01-01

439

Improved reproducibility by assuring confidence in measurements in biomedical research.  

PubMed

‘Irreproducibility’ is symptomatic of a broader challenge in measurement in biomedical research. From the US National Institute of Standards and Technology (NIST) perspective of rigorous metrology, reproducibility is only one aspect of establishing confidence in measurements. Appropriate controls, reference materials, statistics and informatics are required for a robust measurement process. Research is required to establish these tools for biological measurements, which will lead to greater confidence in research results. PMID:25166868

Plant, Anne L; Locascio, Laurie E; May, Willie E; Gallagher, Patrick D

2014-09-01

440

Strategic concealment of sexual identity in an estrilid finch  

PubMed Central

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

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

1999-01-01

441

Dosimetric Algorithm to Reproduce Isodose Curves Obtained from a LINAC  

PubMed Central

In this work isodose curves are obtained by the use of a new dosimetric algorithm using numerical data from percentage depth dose (PDD) and the maximum absorbed dose profile, calculated by Monte Carlo in a 18?MV LINAC. The software allows reproducing the absorbed dose percentage in the whole irradiated volume quickly and with a good approximation. To validate results an 18?MV LINAC with a whole geometry and a water phantom were constructed. On this construction, the distinct simulations were processed by the MCNPX code and then obtained the PDD and profiles for the whole depths of the radiation beam. The results data were used by the code to produce the dose percentages in any point of the irradiated volume. The absorbed dose for any voxel's size was also reproduced at any point of the irradiated volume, even when the voxels are considered to be of a pixel's size. The dosimetric algorithm is able to reproduce the absorbed dose induced by a radiation beam over a water phantom, considering PDD and profiles, whose maximum percent value is in the build-up region. Calculation time for the algorithm is only a few seconds, compared with the days taken when it is carried out by Monte Carlo. PMID:25045398

Estrada Espinosa, Julio Cesar; Martinez Ovalle, Segundo Agustin; Pereira Benavides, Cinthia Kotzian

2014-01-01

442

Mirels’ Rating for Humerus Lesions is Both Reproducible and Valid  

PubMed Central

Mirels’ rating system is commonly used to predict risk of fracture in patients with metastatic bone lesions to long bones, but it has not been independently validated for use in humeral bone lesions. We asked whether this system was a valid and reproducible instrument for predicting impending pathologic fractures in the humerus. We presented 17 case histories and plain radiographs of 16 patients with humeral metastases through a web-based survey to 39 physicians with varying training and experience. Participants scored each case using Mirels’ criteria and provided a fracture prediction, which was compared with actual outcome in the subset of 12 patients with three fractures not treated prophylactically. Using Mirels’ definition of impending pathologic fracture (nine points or greater), the sensitivity and specificity for determining the likelihood of pathologic humeral fracture were 14.5% and 82.9%, respectively. When we used seven or more points as the definition of impending pathologic humeral fracture, sensitivity improved to 81% but specificity was reduced to 32%. Kappa analysis suggested moderate reproducibility across groups for prediction of pathologic fracture. The Mirels rating system for humeral lesions is reproducible and valid, but low specificity at acceptable sensitivity levels as reported remains a problem as for femoral lesions. Level of Evidence: Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18357496

Evans, Andrew R.; Bottros, John; Grant, William; Chen, Benjamin Y.

2008-01-01

443

Reproducibility of LCA Models of Crude Oil Production.  

PubMed

Scientific models are ideally reproducible, with results that converge despite varying methods. In practice, divergence between models often remains due to varied assumptions, incompleteness, or simply because of avoidable flaws. We examine LCA greenhouse gas (GHG) emissions models to test the reproducibility of their estimates for well-to-refinery inlet gate (WTR) GHG emissions. We use the Oil Production Greenhouse gas Emissions Estimator (OPGEE), an open source engineering-based life cycle assessment (LCA) model, as the reference model for this analysis. We study seven previous studies based on six models. We examine the reproducibility of prior results by successive experiments that align model assumptions and boundaries. The root-mean-square error (RMSE) between results varies between ?1 and 8 g CO2 eq/MJ LHV when model inputs are not aligned. After model alignment, RMSE generally decreases only slightly. The proprietary nature of some of the models hinders explanations for divergence between the results. Because verification of the results of LCA GHG emissions is often not possible by direct measurement, we recommend the development of open source models for use in energy policy. Such practice will lead to iterative scientific review, improvement of models, and more reliable understanding of emissions. PMID:25279438

Vafi, Kourosh; Brandt, Adam R

2014-11-01

444

Planar heterojunction perovskite solar cells with superior reproducibility  

PubMed Central

Perovskite solar cells (PeSCs) have been considered one of the competitive next generation power sources. To date, light-to-electric conversion efficiencies have rapidly increased to over 10%, and further improvements are expected. However, the poor device reproducibility of PeSCs ascribed to their inhomogeneously covered film morphology has hindered their practical application. Here, we demonstrate high-performance PeSCs with superior reproducibility by introducing small amounts of N-cyclohexyl-2-pyrrolidone (CHP) as a morphology controller into N,N-dimethylformamide (DMF). As a result, highly homogeneous film morphology, similar to that achieved by vacuum-deposition methods, as well as a high PCE of 10% and an extremely small performance deviation within 0.14% were achieved. This study represents a method for realizing efficient and reproducible planar heterojunction (PHJ) PeSCs through morphology control, taking a major step forward in the low-cost and rapid production of PeSCs by solving one of the biggest problems of PHJ perovskite photovoltaic technology through a facile method. PMID:25377945

Jeon, Ye-Jin; Lee, Sehyun; Kang, Rira; Kim, Jueng-Eun; Yeo, Jun-Seok; Lee, Seung-Hoon; Kim, Seok-Soon; Yun, Jin-Mun; Kim, Dong-Yu

2014-01-01

445

Validity and Reproducibility of a Spanish Dietary History  

PubMed Central

Objective To assess the validity and reproducibility of food and nutrient intake estimated with the electronic diet history of ENRICA (DH-E), which collects information on numerous aspects of the Spanish diet. Methods The validity of food and nutrient intake was estimated using Pearson correlation coefficients between the DH-E and the mean of seven 24-hour recalls collected every 2 months over the previous year. The reproducibility was estimated using intraclass correlation coefficients between two DH-E made one year apart. Results The correlations coefficients between the DH-E and the mean of seven 24-hour recalls for the main food groups were cereals (r?=?0.66), meat (r?=?0.66), fish (r?=?0.42), vegetables (r?=?0.62) and fruits (r?=?0.44). The mean correlation coefficient for all 15 food groups considered was 0.53. The correlations for macronutrients were: energy (r?=?0.76), proteins (r?=?0.58), lipids (r?=?0.73), saturated fat (r?=?0.73), monounsaturated fat (r?=?0.59), polyunsaturated fat (r?=?0.57), and carbohydrates (r?=?0.66). The mean correlation coefficient for all 41 nutrients studied was 0.55. The intraclass correlation coefficient between the two DH-E was greater than 0.40 for most foods and nutrients. Conclusions The DH-E shows good validity and reproducibility for estimating usual intake of foods and nutrients. PMID:24465878

Guallar-Castillon, Pilar; Sagardui-Villamor, Jon; Balboa-Castillo, Teresa; Sala-Vila, Aleix; Ariza Astolfi, M? Jose; Sarrion Pelous, M? Dolores; Leon-Munoz, Luz Maria; Graciani, Auxiliadora; Laclaustra, Martin; Benito, Cristina; Banegas, Jose Ramon; Artalejo, Fernando Rodriguez

2014-01-01

446

Reproducibility of the Optical Biometer OA-1000 (Tomey)  

PubMed Central

Aim. The OA-1000 (Tomey, Japan) is a new optical biometer, which measures axial length (AL), anterior chamber depth (ACD), and central corneal thickness (CT) utilizing optical interference technology. The aim of this study was to prove the reproducibility which is considered fundamental for other clinical investigations. Methods. 55 healthy volunteers were enrolled in this study. For each measurement of AL, ACD, and CT the biometer is grabbing a sequence of 10 shots and mean value (mean) and standard deviation (SD) are displayed. Five consecutive measurements were performed and average and standard deviation were assessed. Cronbach's ? was derived as a quality measure for reproducibility. Results. For AL measurement Cronbach's ? was 1.000, for CT 0.999, and for ACD 0.979, respectively. Mean value for AL was 23.36 ± 1.03?mm, for ACD it was 3.60 ± 0.687?mm, and for CT it was 552.08 ± 29.70??m, respectively. Standard deviation for AL was 0.013 ± 0.022?mm, for ACD 0.09 ± 0.11?mm, and for CT 2.18 ± 1.75??m. One correlation was found between mean values for AL and ACD (R = 0.388, P = 0.005); no other correlations were found between mean values or values of standard deviation of AL, ACD, or CT. Conclusion. The OA-1000 shows an excellent reproducibility for measurement of AL, ACD, and CT and can be used in clinical practice. PMID:24818155

Goebels, Susanne Christiane; Seitz, Berthold; Langenbucher, Achim

2014-01-01

447

Planar heterojunction perovskite solar cells with superior reproducibility.  

PubMed

Perovskite solar cells (PeSCs) have been considered one of the competitive next generation power sources. To date, light-to-electric conversion efficiencies have rapidly increased to over 10%, and further improvements are expected. However, the poor device reproducibility of PeSCs ascribed to their inhomogeneously covered film morphology has hindered their practical application. Here, we demonstrate high-performance PeSCs with superior reproducibility by introducing small amounts of N-cyclohexyl-2-pyrrolidone (CHP) as a morphology controller into N,N-dimethylformamide (DMF). As a result, highly homogeneous film morphology, similar to that achieved by vacuum-deposition methods, as well as a high PCE of 10% and an extremely small performance deviation within 0.14%