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1

Emergence of clones in sexual populations  

NASA Astrophysics Data System (ADS)

In sexual population, recombination reshuffles genetic variation and produces novel combinations of existing alleles, while selection amplifies the fittest genotypes in the population. If recombination is more rapid than selection, populations consist of a diverse mixture of many genotypes, as is observed in many populations. In the opposite regime, which is realized for example in the facultatively sexual populations that outcross in only a fraction of reproductive cycles, selection can amplify individual genotypes into large clones. Such clones emerge when the fitness advantage of some of the genotypes is large enough that they grow to a significant fraction of the population despite being broken down by recombination. The occurrence of this ‘clonal condensation’ depends, in addition to the outcrossing rate, on the heritability of fitness. Clonal condensation leads to a strong genetic heterogeneity of the population which is not adequately described by traditional population genetics measures, such as linkage disequilibrium. Here we point out the similarity between clonal condensation and the freezing transition in the random energy model of spin glasses. Guided by this analogy we explicitly calculate the probability, Y, that two individuals are genetically identical as a function of the key parameters of the model. While Y is the analog of the spin-glass order parameter, it is also closely related to rate of coalescence in population genetics: two individuals that are part of the same clone have a recent common ancestor.

Neher, Richard A.; Vucelja, Marija; Mezard, Mark; Shraiman, Boris I.

2013-01-01

2

Sexual conflict and antagonistic coevolution across water strider populations.  

PubMed

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

Perry, Jennifer C; Rowe, Locke

2012-02-01

3

The maintenance of sexual reproduction in a structured population  

E-print Network

under sexual reproduction. Population subdivision slows the spread of asexual lineages, which allows; asexual reproduction; theory; population genetics; structured populations; genetic drift 1. INTRODUCTIONThe maintenance of sexual reproduction in a structured population Joel R. Peck1* , Jonathan

Alvarez, Nadir

4

Sexual dysfunction in women: population based epidemiological study  

Microsoft Academic Search

Summary  \\u000a Sexual dysfunction is defined as a disturbance of the processes that characterise the sexual response cycle or as pain associated\\u000a with sexual intercourse. The objective of this epidemiological study, conducted in a representative sample of the population\\u000a of women aged 20 and older in Casablanca, Morocco, is to determine the prevalence of sexual dysfunction in women. Criteria\\u000a of sexual

N. Kadri; K. H. Mchichi Alami; S. Mchakra Tahiri

2002-01-01

5

How Sexual Reproduction Affects the Population Biology of  

E-print Network

How Sexual Reproduction Affects the Population Biology of Phytophthora infestans Lina Sjöholm Service/Repro, Uppsala 2012 Cover illustration: Alvar Grönberg #12;How Sexual Reproduction Affects and sexual reproduction. In most parts of the world the asexual part of the life cycle is the dominant

6

Development of Populations 177 6.6 Growth of Populations with Sexual Reproduction  

E-print Network

Development of Populations 177 6.6 Growth of Populations with Sexual Reproduction G. Alsmeyer In Section 5.9, we studied the effect of sexual reproduction on criticality and ex- tinction risk-negative Alsmeyer G (2005). Growth of Populations with Sexual Reproduction. In: Branching Processes: Variation

Alsmeyer, Gerold

7

Sexual Abuse in Childhood and Sexual Dysfunction in Adulthood: An Australian Population-Based Study  

Microsoft Academic Search

This study examined self-reported adult sexual functioning in individuals reporting a history of childhood sexual abuse (CSA) in a representative sample of the Australian population. A sample of 1793 persons, aged 18–59 years, were randomly selected from the electoral roll for Australian states and territories in April 2000. Respondents were interviewed about their health status and sexual experiences, including unwanted

Jake M. Najman; Michael P. Dunne; David M. Purdie; Francis M. Boyle; Peter D. Coxeter

2005-01-01

8

Natural and sexual selection in a monogamous historical human population  

E-print Network

Natural and sexual selection in a monogamous historical human population Alexandre Courtiola,b,c,1 selection in natural populations are well established, our understanding of selection in humans has been of natural and sexual selection in humans that includes the effects of sex and wealth on different episodes

Lummaa, Virpi

9

Sexual abuse in childhood and sexual dysfunction in adulthood: an Australian population-based study.  

PubMed

This study examined self-reported adult sexual functioning in individuals reporting a history of childhood sexual abuse (CSA) in a representative sample of the Australian population. A sample of 1793 persons, aged 18-59 years, were randomly selected from the electoral roll for Australian states and territories in April 2000. Respondents were interviewed about their health status and sexual experiences, including unwanted sexual experiences before the age of 16 years. More than one-third of women and approximately one-sixth of men reported a history of CSA. Women were more likely than men to report both non-penetrative and penetrative experiences of CSA. For both sexes, there was a significant association between CSA and symptoms of sexual dysfunction. In assessing the specific nature of the relationship between sexual abuse and sexual dysfunction, statistically significant associations were, in general, evident for women only. CSA was not associated with the level of physical or emotional satisfaction respondents experienced with their sexual activity. The total number of lifetime sexual partners was significantly and positively associated with CSA for females, but not for males; however, the number of sexual partners in the last year was not related to CSA. CSA in the Australian population is common and contributes to significant impairment in the sexual functioning of adults, especially women. These consequences appear not to extend to the other areas of sexual activity considered in this study. PMID:16211473

Najman, Jake M; Dunne, Michael P; Purdie, David M; Boyle, Francis M; Coxeter, Peter D

2005-10-01

10

The genetic structure of populations of sexual and asexual Taraxacum (dandelions)  

Microsoft Academic Search

The genetic structure, as assessed by isozymes, is described for three populations of outbreeding sexuals, three populations of obligate agamosperms, and six accessions of inbreeding sexual Taraxacum. Fifteen loci in 10 isozyme systems were identified, and isozyme bands were previously shown to be allelic in sexual × sexual and were confirmed as allelic in sexual × agamosperm crosses. Sexual ×

Jane Hughes; A J Richards

1988-01-01

11

Substance Abuse and Sexual Trauma in a Female Veteran Population  

Microsoft Academic Search

An increasing number of researchers have explored connections between substance abuse, posttraumatic stress disorder (PTSD), and sexual assault histories in civilian women. Despite literature suggesting the prevalence of substance abuse and sexual assault for female veterans, few studies have investigated these variables in a female veteran population. Thus, this paper was designed to provide preliminary information about this group of

Tania M. Davis; Peggy S. Wood

1999-01-01

12

The Association between Childhood and Adolescent Sexual Abuse and Proxies for Sexual Risk Behavior: A Random Sample of the General Population of Sweden  

ERIC Educational Resources Information Center

Objective: Several studies with small and ''high risk'' samples have demonstrated that a history of childhood or adolescent sexual abuse (CASA) is associated with sexual risk behaviors (SRBs). However, few studies with large random samples from the general population have specifically examined the relationship between CASA and SRBs with a…

Steel, Jennifer L.; Herlitz, Claes A.

2005-01-01

13

Population structure and diversity in sexual and asexual populations of the pathogenic fungus Melampsora lini  

PubMed Central

Many pathogens undergo both sexual and asexual reproduction to varying degrees, yet the ecological, genetic and evolutionary consequences of different reproductive strategies remain poorly understood. Here we investigate the population genetic structure of wild populations of the plant pathogen Melampsora lini on its host Linum marginale, using amplified fragment length polymorphism (AFLP) markers, two genes underlying pathogen virulence, and phenotypic variation in virulence. In Australia, M. lini occurs as two genetically and geographically divergent lineages (AA and AB), one of which is completely asexual (AB), and the other able to reproduce both clonally and sexually (AA). To quantify the genetic and evolutionary consequences of these different life histories, we sampled five populations in each of two biogeographical regions. Analysis of AFLP data obtained for 275 isolates revealed largely disjunct geographical distributions for the two different lineages, low genetic diversity within lineages, and strong genetic structure among populations within each region. We also detected significant divergence among populations for both Avr genes and virulence phenotypes, although generally these values were lower than those obtained with AFLP markers. Furthermore, isolates belonging to lineage AA collectively harboured significantly higher genotypic and phenotypic diversity than lineage AB isolates. Together these results illustrate the important roles of reproductive modes and geographical structure in the generation and maintenance of virulence diversity in populations of M. lini. PMID:18573166

BARRETT, LUKE G.; THRALL, PETER H.; BURDON, JEREMY J.; NICOTRA, ADRIENNE B.; LINDE, CELESTE C.

2009-01-01

14

Assessment of female sexual arousal in forensic populations.  

PubMed

Sexual offenses cause significant harm to victims, their families, and society as a whole and thus are an important social concern. While it is commonly assumed that sexual offenses are committed solely by males, research has shown that approximately 5 % of sex crimes in the USA and Canada are committed by females. Penile plethysmography (PPG) is a method to measure male genital arousal, which is commonly used in the assessment and treatment of male sex offenders and men with paraphilic sexual interests. Similarly, vaginal photoplethysmography (VPP) is a test to measure female genital arousal and is commonly used to assess female sexual dysfunctions. Although VPP is currently the most validated method to measure genital arousal in women, its use with female sex offenders or females with paraphilic sexual interests has been almost nonexistent. One explanation for this is that some research has suggested that female genital arousal may not be category-specific, meaning that women will respond to any sexual cues, not just those involving their preferred sexual interests. However, not all research supports this finding. Due to the potential benefits of using VPP in the assessment and treatment of female sex offenders or females with paraphilic sexual interests, it is important that further research be done before dismissing the use of VPP in forensic populations. The purpose of this article is to review the current research on VPP and its applicability to female sex offenders and females with paraphilic sexual interests. PMID:25749745

Knack, Natasha M; Murphy, Lisa; Ranger, Rebekah; Meston, Cindy; Fedoroff, J Paul

2015-04-01

15

Are Eukaryotic Microorganisms Clonal or Sexual? A Population Genetics Vantage  

Microsoft Academic Search

We argue that the mode of reproduction of microorganisms in nature can only be decided by population genetic information. The evidence available indicates that many parasitic protozoa and unicellular fungi have clonal rather than sexual population structures, which has major consequences for medical research and practice. Plasmodium falciparum, the agent of malaria, is a special case: the scarce evidence available

Michel Tibayrenc; Finn Kjellberg; Jacques Arnaud; Bruno Oury; S. Frederique Breniere; Marle-Laure Darde; Francisco J. Ayala

1991-01-01

16

How Large Asexual Populations Adapt  

NASA Astrophysics Data System (ADS)

We often think of beneficial mutations as being rare, and of adaptation as a sequence of selected substitutions: a beneficial mutation occurs, spreads through a population in a selective sweep, then later another beneficial mutation occurs, and so on. This simple picture is the basis for much of our intuition about adaptive evolution, and underlies a number of practical techniques for analyzing sequence data. Yet many large and mostly asexual populations -- including a wide variety of unicellular organisms and viruses -- live in a very different world. In these populations, beneficial mutations are common, and frequently interfere or cooperate with one another as they all attempt to sweep simultaneously. This radically changes the way these populations adapt: rather than an orderly sequence of selective sweeps, evolution is a constant swarm of competing and interfering mutations. I will describe some aspects of these dynamics, including why large asexual populations cannot evolve very quickly and the character of the diversity they maintain. I will explain how this changes our expectations of sequence data, how sex can help a population adapt, and the potential role of ``mutator'' phenotypes with abnormally high mutation rates. Finally, I will discuss comparisons of these predictions with evolution experiments in laboratory yeast populations.

Desai, Michael

2007-03-01

17

Population genetic structure of sexual and parthenogenetic damselflies inferred from mitochondrial and nuclear markers  

PubMed Central

It has been postulated that obligate asexual lineages may persist in the long term if they escape from negative interactions with either sexual lineages or biological enemies; and thus, parthenogenetic populations will be more likely to occur in places that are difficult for sexuals to colonize, or those in which biological interactions are rare, such as islands or island-like habitats. Ischnura hastata is the only known example of natural parthenogenesis within the insect order Odonata, and it represents also a typical example of geographic parthenogenesis, as sexual populations are widely distributed in North America, whereas parthenogenetic populations of this species have only been found at the Azores archipelago. In order to gain insight in the origin and distribution of parthenogenetic I. hastata lineages, we have used microsatellites, mitochondrial and nuclear DNA sequence data, to examine the population genetic structure of this species over a wide geographic area. Our results suggest that sexual populations of I. hastata in North America conform to a large subdivided population that has gone through a recent spatial expansion. A recent single long distance dispersal event, followed by a demographic expansion, is the most parsimonious hypothesis explaining the origin of the parthenogenetic population of this species in the Azores islands. PMID:21915148

Lorenzo-Carballa, M O; Hadrys, H; Cordero-Rivera, A; Andrés, J A

2012-01-01

18

Stellar Populations at Large Redshifts  

E-print Network

Rapid progress is now being made in the study of stellar populations of galaxies at large lookback times, both in dense clusters and the field. Dramatic transformations in star formation histories (even morphologies) appear to prevail among all types of galaxies and in all environments, and these can be traced to relatively recent times (z ~ 0.2). This article updates to December 1998 a review made in 1994 to cover the recent watershed of observational results emerging from the Hubble Deep Field and deep surveys made with large ground-based telescopes.

Robert W. O'Connell

1999-03-27

19

On the Unit of Selection in Sexual Populations  

Microsoft Academic Search

Evolution by natural selection is a process of var iation and selection acting on replicating units. These units are often assumed to be individuals, but in a sexual population, the largest reliably-replic ated unit on which selection can act is a small section of chromosome - hence, t he 'selfish gene' model. However, the scale of unit at which variation

Richard A. Watson

2005-01-01

20

Sexual Conf lict and Remarriage in Preindustrial Human Populations  

Microsoft Academic Search

Sexual conflict is said to occur when one mating partner has an opportunity to increase its fitness at the cost of the other. We analyzed the effect of remarriage on lifetime reproductive success (LRS) in three preindustrial (1700–1900) socially monogamous Sami populations. In all populations, ever-married women’s age-specific mortality rates exceeded those of ever-married men during reproductive years. After the

Pekka Käär; Jukka Jokela; Juha Merilä; Timo Helle; Ilpo Kojola

1998-01-01

21

Sexual recombination punctuated by outbreaks and clonal expansions predicts Toxoplasma gondii population genetics  

PubMed Central

The cosmopolitan parasitic pathogen Toxoplasma gondii is capable of infecting essentially any warm-blooded vertebrate worldwide, including most birds and mammals, and establishes chronic infections in one-third of the globe’s human population. The success of this highly prevalent zoonosis is largely the result of its ability to propagate both sexually and clonally. Frequent genetic exchanges via sexual recombination among extant parasite lineages that mix in the definitive felid host produces new lines that emerge to expand the parasite’s host range and cause outbreaks. Highly successful lines spread clonally via carnivorism and in some cases sweep to pandemic levels. The extent to which sexual reproduction versus clonal expansion shapes Toxoplasma’s current, global population genetic structure is the central question this review will attempt to answer. PMID:19217909

Grigg, Michael E.; Sundar, Natarajan

2009-01-01

22

Sexually transmitted disease epidemics in a natural insect population.  

PubMed

1. The epidemiology of sexually transmitted diseases (STDs) in human and domesticated populations is well documented. However, there has been less study of STDs in natural populations. 2. We investigated STD dynamics in the model system involving a host from the most speciose group of animals: the insects. We investigated temporal variation in the prevalence of the sexually transmitted mite Coccipolipus hippodamiae on its ladybird host, Adalia bipunctata. 3. Field surveys over two seasons showed a repeated pattern of a profound epidemic in the overwintered cohort and a later prevalence decline. 4. In order to understand the key factors in the dynamics of this system we studied the phenology of the host and simulated parasite dynamics in the overwintered cohort using a model with within-sex homogeneity in mating rate and field-measured parameter values. The similarity of natural and simulation prevalence levels allowed us to carry out sensitivity analysis and hence to identify the key determinants of the dynamics. 5. The observed pattern of periodic extreme prevalence combined with system persistence probably results from time lags in host recruitment and widespread promiscuity. 6. Our findings improve our understanding of STDs in natural populations and illustrate the importance of examining seasonality and time delays in population dynamics in order to fully understand the characteristics of natural populations and their parasites. PMID:16903041

Webberley, K Mary; Buszko, Jaros?aw; Isham, Valerie; Hurst, Gregory D D

2006-01-01

23

Size-dependent male mating behaviour and sexual harassment in a population of Atlantic mollies ( Poecilia mexicana ) from a sulphur creek  

Microsoft Academic Search

The Atlantic molly Poecilia mexicana inhabits a variety of habitats. In previous studies, small males from clear-water populations showed considerably more sexual behaviours than large males. Males from a sulphur creek, the El Azufre, or from a sulphur cave (cave molly) showed comparatively low sexual activity, and typical size-dependent mating behaviour was either absent or large males showed even more

Martin Plath; Anja Brümmer; Jakob Parzefall; Ingo Schlupp

2006-01-01

24

Sexual harassment in a live-bearing fish ( Poecilia mexicana ): influence of population-specific male mating behaviour  

Microsoft Academic Search

We investigated male sexual behaviour and the cost of sexual harassment, as measured by the reduction of female feeding time in the presence of a male, in a cave-dwelling population of Poecilia mexicana, in which sexual harassment does not occur naturally. We asked whether the lack of sexual harassment in this population is due to low sexual activity of the

Martin Plath; Anja Brümmer; Ingo Schlupp

2004-01-01

25

Natural and sexual selection in a monogamous historical human population.  

PubMed

Whether and how human populations exposed to the agricultural revolution are still affected by Darwinian selection remains controversial among social scientists, biologists, and the general public. Although methods of studying selection in natural populations are well established, our understanding of selection in humans has been limited by the availability of suitable datasets. Here, we present a study comparing the maximum strengths of natural and sexual selection in humans that includes the effects of sex and wealth on different episodes of selection. Our dataset was compiled from church records of preindustrial Finnish populations characterized by socially imposed monogamy, and it contains a complete distribution of survival, mating, and reproductive success for 5,923 individuals born 1760-1849. Individual differences in early survival and fertility (natural selection) were responsible for most variation in fitness, even among wealthier individuals. Variance in mating success explained most of the higher variance in reproductive success in males compared with females, but mating success also influenced reproductive success in females, allowing for sexual selection to operate in both sexes. The detected opportunity for selection is in line with measurements for other species but higher than most previous reports for human samples. This disparity results from biological, demographic, economic, and social differences across populations as well as from failures by most previous studies to account for variation in fitness introduced by nonreproductive individuals. Our results emphasize that the demographic, cultural, and technological changes of the last 10,000 y did not preclude the potential for natural and sexual selection in our species. PMID:22547810

Courtiol, Alexandre; Pettay, Jenni E; Jokela, Markus; Rotkirch, Anna; Lummaa, Virpi

2012-05-22

26

Natural and sexual selection in a monogamous historical human population  

PubMed Central

Whether and how human populations exposed to the agricultural revolution are still affected by Darwinian selection remains controversial among social scientists, biologists, and the general public. Although methods of studying selection in natural populations are well established, our understanding of selection in humans has been limited by the availability of suitable datasets. Here, we present a study comparing the maximum strengths of natural and sexual selection in humans that includes the effects of sex and wealth on different episodes of selection. Our dataset was compiled from church records of preindustrial Finnish populations characterized by socially imposed monogamy, and it contains a complete distribution of survival, mating, and reproductive success for 5,923 individuals born 1760–1849. Individual differences in early survival and fertility (natural selection) were responsible for most variation in fitness, even among wealthier individuals. Variance in mating success explained most of the higher variance in reproductive success in males compared with females, but mating success also influenced reproductive success in females, allowing for sexual selection to operate in both sexes. The detected opportunity for selection is in line with measurements for other species but higher than most previous reports for human samples. This disparity results from biological, demographic, economic, and social differences across populations as well as from failures by most previous studies to account for variation in fitness introduced by nonreproductive individuals. Our results emphasize that the demographic, cultural, and technological changes of the last 10,000 y did not preclude the potential for natural and sexual selection in our species. PMID:22547810

Courtiol, Alexandre; Pettay, Jenni E.; Jokela, Markus; Rotkirch, Anna; Lummaa, Virpi

2012-01-01

27

Associations between early first sexual intercourse and later sexual and reproductive outcomes: a systematic review of population-based data.  

PubMed

The assumption that early sexual debut leads to adverse outcomes has been used as justification for sexual health interventions and policies aimed at delaying sexual initiation, yet research in the area has been limited. This review identified and synthesized published literature on the association between early first sexual intercourse and later sexual/reproductive outcomes. Literature searches were conducted in Medline, Embase, PsycINFO, and Current Contents. In all, 65 citations met the selection criteria (industrialized, population-based studies). By far the most common sexual behavior to have been investigated has been sexual partners. Studies consistently reported early first intercourse to be associated with more recent, lifetime, and concurrent sexual partners. Early initiators were also more likely to participate in a wider range of sexual practices and report increased sexual satisfaction (among men). Furthermore, early first intercourse, in some studies, was shown to increase the risk of teen pregnancies, teen births, and having an abortion, while findings on STIs and contraceptive use have been mixed. These findings, however, must be interpreted with caution due to methodological problems and limitations present in the research, including a lack of consensus on what constitutes early sexual intercourse and inconsistencies and problems with analyses. PMID:25425161

Heywood, Wendy; Patrick, Kent; Smith, Anthony M A; Pitts, Marian K

2015-04-01

28

Rate of fixation of beneficial mutations in sexual populations  

NASA Astrophysics Data System (ADS)

We have investigated the rate of substitution of advantageous mutations in populations of haploid organisms where the rate of recombination can be controlled. We have verified that in all the situations recombination speeds up adaptation through recombination of beneficial mutations from distinct lineages in a single individual, and so reducing the intensity of clonal interference. The advantage of sex for adaptation is even stronger when deleterious mutations occur since now recombination can also restore genetic background free of deleterious mutations. However, our simulation results demonstrate that evidence of clonal interference, as increased mean selective effect of fixed mutations and reduced likelihood of fixation of small-effect mutations, are also present in sexual populations. What we see is that this evidence is delayed when compared to asexual populations.

Gouveia, Joseilme F.; de Oliveira, Viviane M.; Sátiro, Caio; Campos, Paulo R. A.

2009-06-01

29

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

E-print Network

was characterized in three populations of the wild strawberry, Fragaria virginiana, to determine the extent, Fragaria virginiana, microsatellites, population genetic structure. INTRODUCTION Many plant speciesHigh variation in clonal vs. sexual reproduction in populations of the wild strawberry, Fragaria

Ashley, Mary V.

30

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

PubMed Central

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

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

2013-01-01

31

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

32

[Sexually transmissible disorders in allochtonous population groups; a pilot study].  

PubMed

In the registration of sexually transmitted diseases (STD) carried out by the nursing staff in the STD clinics the share of the immigrant populations of Turkish, Moroccan, Surinam and Antilles origin was investigated for the period 1986-89. In the total population of STD patients the immigrants appear to be overrepresented. Their share has increased from one-eight to one-fifth of the total number of STD cases. The STD rates (number of cases per 1000) for the Turkish and Moroccan populations are high, even after adjusting for population size and age. High STD rates are most apparent among males, especially among Turkish males. In comparison with the Dutch population more gonorrhoea is found among immigrants, in particular penicillinase producing Neisseria gonorrhoeae (PPNG). Turkish males (and prostitutes) contributed much to this relatively high prevalence. Further research is to be initiated in order to obtain better insight into the occurrence of STD among immigrant populations in The Netherlands, especially in connection with a potentially increased risk of infection with Human Immunodeficiency Virus (HIV). PMID:1922482

van de Laar, M J; Sleutjes, M P; Postema, C A; van de Water, H P

1991-08-24

33

Severely reduced sexual reproduction in northern populations of a clonal plant, Decodon verticillatus (Lythraceae)  

Microsoft Academic Search

Summary 1 In flowering plants the balance between sexual and clonal, asexual reproduction can vary widely. We quantified variation in sexual reproduction in a tristylous, clonal, aquatic plant, Decodon verticillatus , and investigated the role of ecological and genetic factors in causing this variation. 2 We surveyed components of sexual fertility and vegetative growth in 28 populations distributed along a

Marcel E. Dorken; CHRISTOPHER G. ECKERT

2001-01-01

34

Cryptic sexual populations account for genetic diversity and ecological success in a widely distributed, asexual  

E-print Network

, but their existence in sexual populations is indicated by the presence of sperm in the reproductive tracts of queens sexual reproduction is favored by natural se- lection over short evolutionary time spans and, if not, why sexual reproduction persists as the prevalent mode of reproduction, given that the selective benefits

Bi, Xin

35

Adult Sexual Assault: Prevalence, Symptomatology, and Sex Differences in the General Population  

Microsoft Academic Search

The prevalence and impact of adult sexual assault (ASA) were examined in a stratified random sample of the general population. Among 941 participants, ASA was reported by 22% of women and 3.8% of men. Multivariate risk factors for ASA included a younger age, being female, having been divorced, sexual abuse in childhood, and physical assault in adulthood. Childhood sexual abuse

Diana M. Elliott; Doris S. Mok; John Brierel

2004-01-01

36

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

NASA Astrophysics Data System (ADS)

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

Neher, Richard

2010-03-01

37

Sexually Coercive Behavior in Male Youth: Population Survey of General and Specific Risk Factors  

Microsoft Academic Search

Little is known about risk\\/protective factors for sexually coercive behavior in general population youth. We used a Swedish\\u000a school-based population survey of sexual attitudes and experiences (response rate 77%) and investigated literature-based variables\\u000a across sexually coercive (SEX), non-sexual conduct problem (CP), and normal control (NC) participants to identify general\\u000a and specific risk\\/protective factors for sexual coercion. Among 1,933 male youth,

Cecilia Kjellgren; Gisela Priebe; Carl Göran Svedin; Niklas Långström

2010-01-01

38

Validity of Physiological Measures of Pedophilic Sexual Arousal in a Sexual Offender Population  

Microsoft Academic Search

Sexual arousal, as measured by penile erection, in response to nondeviant and pedophilic audiotapes was analyzed in a sample of 122 inpatient adult male sexual offenders. Eighty percent of the subjects were able to voluntarily and completely inhibit their sexual arousal. Multivariate analyses suggested that nondeviant and deviant arousal were significantly associated and that sexual arousal as a male voice

Gordon C. Nagayama Hall; William C. Proctor; George M. Nelson

1988-01-01

39

Sexual offender recidivism among a population-based prison sample.  

PubMed

The present study examines recidivism rates in sexual offenders using officially registered reconvictions in a representative data set of N = 1,115 male sexual offenders from Austria. In general, results indicate that most sexual offenders do not reoffend sexually after release from prison. More detailed, within the first 5 years after release, the sexual recidivism rate was 6% for the total sample, 4% for the rapist subgroup, and 8% for the child molester subgroup. The findings confirmed previous studies about sex offender recidivism which have shown that first-time sexual offenders are significantly less likely to sexually reoffend than those with previous sexual convictions. With regard to the relationship between age and sexual recidivism, the results challenged the traditional assumption of a clear linear function between age and recidivism. Taken together, compared with previous studies, the recidivism rates found in the present investigation are substantially lower than previous research has indicated. PMID:24398599

Rettenberger, Martin; Briken, Peer; Turner, Daniel; Eher, Reinhard

2015-04-01

40

Predictors of Sexual Bother in a Population of Male North American Medical Students  

PubMed Central

Introduction The prevalence and associations of sexual bother in male medical students has not been extensively studied. Aims The aim of this study is to analyze predictors of sexual bother in a survey of male North American medical students. Methods Students enrolled in allopathic and osteopathic medical schools in North America between February 2008 and July 2008 were invited to participate in an internet-based survey of sexuality and sexual function. Main Outcome Measures The principle outcome measure was a single-item question inquiring about global satisfaction with sexual function. The survey also consisted of a questionnaire that included ethnodemographic factors, student status, sexual history, and a validated scale for the assessment of depression. Respondents completed the International Index of Erectile Function, the premature ejaculation diagnostic tool, and the Self-Esteem and Relationship Quality survey (SEAR). Descriptive statistics, analysis of variance, and multivariable logistic regression were utilized to analyze responses. Results There were 480 male subjects (mean age 26.3 years) with data sufficient for analysis. Forty-three (9%) reported sexual bother. Sexual bother was significantly more common in men with erectile dysfunction (ED), high risk of premature ejaculation (HRPE), depressive symptoms, and lower sexual frequency. However, after multivariate analysis including SEAR scores, ED, and HRPE were no longer independently predictive of sexual bother. Higher scores for all domains of the SEAR were associated with lower odds of sexual bother. Conclusions ED and HRPE are associated with sexual bother in this young and presumably healthy population. However, after controlling for relationship factors neither ED nor HRPE independently predicted sexual bother. It is plausible to hypothesize that sexual dysfunction from organic causes is rare in this population and is seldom encountered outside of relationship perturbations. Attention to relationship and psychological factors is likely of key importance in addressing sexual concerns in this population. PMID:21951580

Smith, James F.; Breyer, Benjamin N.; Shindel, Alan W.

2013-01-01

41

Sexually coercive behavior in male youth: population survey of general and specific risk factors.  

PubMed

Little is known about risk/protective factors for sexually coercive behavior in general population youth. We used a Swedish school-based population survey of sexual attitudes and experiences (response rate 77%) and investigated literature-based variables across sexually coercive (SEX), non-sexual conduct problem (CP), and normal control (NC) participants to identify general and specific risk/protective factors for sexual coercion. Among 1,933 male youth, 101 (5.2%) reported sexual coercion (ever talked or forced somebody into genital, oral, or anal sex) (SEX), 132 (6.8%) were classified as CP, and the remaining 1,700 (87.9%) as NC. Of 29 tested variables, 25 were more common in both SEX and CP compared to NC youth, including minority ethnicity, separated parents, vocational study program, risk-taking, aggressiveness, depressive symptoms, substance abuse, sexual victimization, extensive sexual experiences, and sexual preoccupation. When compared to CP youth only, SEX youth more often followed academic study programs, used less drugs and were less risk-taking. Further, SEX more frequently than CP youth reported gender stereotypic and pro-rape attitudes, sexual preoccupation, prostitution, and friends using violent porn. Finally, in a multivariate logistic regression, academic study program, pro-rape attitudes, sexual preoccupation, and less risk-taking independently remained more strongly associated with SEX compared to CP offending. In conclusion, several sociodemographic, family, and individual risk/protective factors were common to non-sexual and sexually coercive antisocial behavior in late adolescence. However, pro-rape cognitions, and sexual preoccupation, were sexuality-related, specific risk factors. The findings could inform preventive efforts and the assessment and treatment of sexually coercive male youth. PMID:19888644

Kjellgren, Cecilia; Priebe, Gisela; Svedin, Carl Göran; Långström, Niklas

2010-10-01

42

A population of sexual Daphnia pulex resists invasion by asexual clones.  

PubMed

Asexual reproduction avoids the costs associated with sex, predicting that invading asexual clones can quickly replace sexual populations. Daphnia pulex populations in the Great Lakes area are predominately asexual, but the elimination of sexual populations by invading clones is poorly understood. Asexual clones were detected at low frequency in one rare sexual population in 1995, with some increase in frequency during 2003 and 2004. However, these clones remained at low frequency during further yearly sampling (2005-2013) with no evidence that the resident sexual population was in danger of elimination. There was evidence for hybridization between rare males produced by asexual clones and sexual females with the potential to produce new asexual genotypes and spread the genetic factors for asexuality. In a short-term laboratory competition experiment, the two most common asexual clones did not increase in frequency relative to a genetically diverse sexual population due in part to a greater investment in diapausing eggs that trades-off current population growth for increased contribution to the egg bank. Our results suggest that a successful invasion can be prolonged, requiring a combination of clonal genotypes with high fitness, persistence of clones in the egg bank and negative factors affecting the sexual population such as inbreeding depression resulting from population bottlenecks. PMID:24943366

Innes, David J; Ginn, Michael

2014-08-01

43

Infection dynamics in coexisting sexual and asexual host populations: support for the Red Queen hypothesis.  

PubMed

The persistence of sexual reproduction is a classic problem in evolutionary biology. The problem stems from the fact that, all else equal, asexual lineages should rapidly replace coexisting sexual individuals due to the cost of producing males in sexual populations. One possible countervailing advantage to sexual reproduction is that, on average, outcrossed offspring are more resistant than common clones to coevolving parasites, as predicted under the Red Queen hypothesis. In this study, we evaluated the prevalence of infection by a sterilizing trematode (Microphallus sp.) in a natural population of freshwater snails that was composed of both sexual and asexual individuals (Potamopyrgus antipodarum). More specifically, we compared the frequency of infection in sexual and asexual individuals over a 5-year period at four sites at a natural glacial lake (Lake Alexandrina, South Island, New Zealand). We found that at most sites and over most years, the sexual population was less infected than the coexisting asexual population. Moreover, the frequency of uninfected sexual females was periodically greater than two times the frequency of uninfected asexual females. These results give clear support for a fluctuating parasite-mediated advantage to sexual reproduction in a natural population. PMID:25061675

Vergara, Daniela; Jokela, Jukka; Lively, Curtis M

2014-08-01

44

Medfly populations differ in diel and age patterns of sexual signalling  

PubMed Central

Insect populations may differ in several life history traits, including behavioural ones such as sexual signalling. We tested whether male Mediterranean fruit fly (medlfy), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), populations obtained from geographically isolated areas exhibit differences in quantitative and qualitative aspects of male sexual signalling. Male sexual signalling was studied in four medfly populations (originating from Brazil, Portugal, Kenya, and Greece) under identical laboratory conditions (25 °C, 60% r.h., and L14:D10). The four populations had been reared for one generation in the laboratory. Sexual signalling was studied in the F1 progeny that were fed one of two diets (yeast hydrolysate plus sugar or sugar only). On both diets, the four populations differed significantly in the progress of maturity (indicated by the average number of males exhibiting sexual signalling) and in the quantity of signalling after attaining maturity. Yeast availability significantly increased sexual signalling; however, it had a different impact on the quantity of signalling in the different populations. A bimodal pattern of sexual signalling, with one peak at approximately 08:00–09:00 hours and the second at approximately 13:00–14:00 hours, was recorded for all populations and diets. However, quantitative differences among the populations within the ‘sexually active’ period of the day resulted in significant differences in the daily pattern of sexual signalling. The significance of these findings for understanding adaptations of geographically-isolated medfly populations to different ecosystems, as well as its practical importance for the application of the Sterile Insect Technique (SIT) against C. capitata, is discussed. PMID:19774092

Diamantidis, Alexandros D.; Papadopoulos, Nikos T.; Carey, James R.

2009-01-01

45

Medfly populations differ in diel and age patterns of sexual signalling.  

PubMed

Insect populations may differ in several life history traits, including behavioural ones such as sexual signalling. We tested whether male Mediterranean fruit fly (medlfy), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), populations obtained from geographically isolated areas exhibit differences in quantitative and qualitative aspects of male sexual signalling. Male sexual signalling was studied in four medfly populations (originating from Brazil, Portugal, Kenya, and Greece) under identical laboratory conditions (25 °C, 60% r.h., and L14:D10). The four populations had been reared for one generation in the laboratory. Sexual signalling was studied in the F(1) progeny that were fed one of two diets (yeast hydrolysate plus sugar or sugar only). On both diets, the four populations differed significantly in the progress of maturity (indicated by the average number of males exhibiting sexual signalling) and in the quantity of signalling after attaining maturity. Yeast availability significantly increased sexual signalling; however, it had a different impact on the quantity of signalling in the different populations. A bimodal pattern of sexual signalling, with one peak at approximately 08:00-09:00 hours and the second at approximately 13:00-14:00 hours, was recorded for all populations and diets. However, quantitative differences among the populations within the 'sexually active' period of the day resulted in significant differences in the daily pattern of sexual signalling. The significance of these findings for understanding adaptations of geographically-isolated medfly populations to different ecosystems, as well as its practical importance for the application of the Sterile Insect Technique (SIT) against C. capitata, is discussed. PMID:19774092

Diamantidis, Alexandros D; Papadopoulos, Nikos T; Carey, James R

2008-09-01

46

High Rates of Sexual Behavior in the General Population: Correlates and Predictors  

Microsoft Academic Search

We studied 2450, 18–60-year-old men and women from a 1996 national survey of sexuality and health in Sweden to identify risk\\u000a factors and correlates of elevated rates of sexual behavior (hypersexuality) in a representative, non-clinical population.\\u000a Interviews and questionnaires measured various sexual behaviors, developmental risk factors, behavioral problems, and health\\u000a indicators. The results suggested that correlates of high rates of

Niklas Långström; R. Karl Hanson

2006-01-01

47

Consequences of Acne on Stress, Fatigue, Sleep Disorders and Sexual Activity: A Population-based Study.  

PubMed

Acne is a common disease among young people, which could have a serious impact on quality of life. Based on a survey using the quotas method on a large sample of the French population, we studied the impact of acne on feelings of stress, fatigue upon waking, sleep disorders and sexual activity. We did not establish any relationship to sleep disorders, but clearly ascertained that people with acne (n?=?1,375) feel more stressed and have less sexual intercourse. Hence, 18% of people from acne group declared to be stressed every day (13.9% in control group) and 37.5% had no sexual intercourse (20.4% in control group; n?=?891). To our knowledge, this is the first study to show that fatigue upon waking is strongly associated with the presence of acne (65.4% versus 58.4%). This study emphasises the fact that acne could have a deep resounding impact on the lives of people suffering from the disease. PMID:25365961

Misery, Laurent; Wolkenstein, Pierre; Amici, Jean-Michel; Maghia, Rémi; Brenaut, Emilie; Cazeau, Christine; Voisard, Jean-Jacques; Taïeb, Charles

2015-04-15

48

Sexual behaviour, STDs and drug use in a crack house population.  

PubMed

We aimed to investigate the prevalence of ulcerative sexually transmissible diseases (STDs) and hepatitis in crack users. We interviewed 435 crack users on site in crack houses in Houston, Texas and took blood for laboratory analysis. There was evidence of syphilis infection in 13%, herpes simplex virus-2 (HSV-2) in 61%, HIV in 12%, hepatitis B in 52%, and hepatitis C in 41% of cases. On DSM-III-R criteria, 12% were crack abusers and 84% crack dependent: over half reported previous treatment. Forty per cent reported also injecting. Sexual behaviour indicated a mean of 2.4 partners in the past month for men, 3.7 for women. Sexual behaviour was largely vaginal, although women also reported more than twice the level of oral sex of men. Significant multivariate predictors for HIV and hepatitis B and C were previous reported STD and injecting drug use (including sharing needles), while female gender for syphilis and HSV-2, and additionally condom use for HSV-2, were significant risks. These data confirm high rates of STDs in a crack house population as inferred from previous clinic-based and community studies, and the link between STDs, injecting and HIV. The high rates of STDs found should lead to considering STDs and substance abuse to be dual diagnoses in crack users and the integration of STD diagnosis and treatment into crack outreach and treatment programmes. PMID:12035774

Ross, M W; Hwang, L Y; Leonard, L; Teng, M; Duncan, L

1999-04-01

49

Sexual size dimorphism in bighorn sheep ( Ovis canadensis ): effects of population density  

Microsoft Academic Search

Sexual dimorphism is an important characteristic of many mammals, but little is known about how environ- mental variables may affect its phenotypic expression. The relationships between population size, body mass, seasonal mass changes, and sexual mass dimorphism were investigated using 22 years of data on individually marked bighorn sheep (Ovis canadensis) on Ram Mountain, Alberta. The number of adult ewes

Mylène LeBlanc; Marco Festa-Bianchet; Jon T. Jorgenson

2001-01-01

50

Posttraumatic stress associated with delayed recall of sexual abuse: A general population study  

Microsoft Academic Search

This study examined delayed recall of childhood sexual abuse in a stratified random sample of the general population (N=505). Of participants who reported a history of sexual abuse, 42% described some period of time when they had less memory of the abuse than they did at the time of data collection. No demographic differences were found between subjects with continuous

Diana M. Elliott; John Briere

1995-01-01

51

Sexually Transmitted Diseases and Risk Behaviors among California Farmworkers: Results from a Population-Based Survey  

ERIC Educational Resources Information Center

Context: The prevalence of sexually transmitted diseases and associated risk behaviors among California farmworkers is not well described. Purpose: To estimate the prevalence of sexually transmitted diseases (STDs) and associated risk behaviors among California farmworkers. Methods: Cross-sectional analysis of population-based survey data from 6…

Brammeier, Monique; Chow, Joan M.; Samuel, Michael C.; Organista, Kurt C.; Miller, Jamie; Bolan, Gail

2008-01-01

52

Patterns of Vaginal, Oral, and Anal Sexual Intercourse in an Urban Seventh-Grade Population  

ERIC Educational Resources Information Center

Background: This study examines the prevalence of vaginal, oral, and anal intercourse among a population of urban, public middle school students, the characteristics of early sexual initiators, and the sequence of sexual initiation. Such data are limited for early adolescents. Methods: A total of 1279 seventh-grade students (57.3% female, 43.6%…

Markham, Christine M.; Peskin, Melissa Fleschler; Addy, Robert C.; Baumler, Elizabeth R.; Tortolero, Susan R.

2009-01-01

53

Coalescence and genetic diversity in sexual populations under selection  

PubMed Central

In sexual populations, selection operates neither on the whole genome, which is repeatedly taken apart and reassembled by recombination, nor on individual alleles that are tightly linked to the chromosomal neighborhood. The resulting interference between linked alleles reduces the efficiency of selection and distorts patterns of genetic diversity. Inference of evolutionary history from diversity shaped by linked selection requires an understanding of these patterns. Here, we present a simple but powerful scaling analysis identifying the unit of selection as the genomic “linkage block” with a characteristic length, , determined in a self-consistent manner by the condition that the rate of recombination within the block is comparable to the fitness differences between different alleles of the block. We find that an asexual model with the strength of selection tuned to that of the linkage block provides an excellent description of genetic diversity and the site frequency spectra compared with computer simulations. This linkage block approximation is accurate for the entire spectrum of strength of selection and is particularly powerful in scenarios with many weakly selected loci. The latter limit allows us to characterize coalescence, genetic diversity, and the speed of adaptation in the infinitesimal model of quantitative genetics. PMID:24019480

Neher, Richard A.; Kessinger, Taylor A.; Shraiman, Boris I.

2013-01-01

54

Coalescence and genetic diversity in sexual populations under selection.  

PubMed

In sexual populations, selection operates neither on the whole genome, which is repeatedly taken apart and reassembled by recombination, nor on individual alleles that are tightly linked to the chromosomal neighborhood. The resulting interference between linked alleles reduces the efficiency of selection and distorts patterns of genetic diversity. Inference of evolutionary history from diversity shaped by linked selection requires an understanding of these patterns. Here, we present a simple but powerful scaling analysis identifying the unit of selection as the genomic "linkage block" with a characteristic length, , determined in a self-consistent manner by the condition that the rate of recombination within the block is comparable to the fitness differences between different alleles of the block. We find that an asexual model with the strength of selection tuned to that of the linkage block provides an excellent description of genetic diversity and the site frequency spectra compared with computer simulations. This linkage block approximation is accurate for the entire spectrum of strength of selection and is particularly powerful in scenarios with many weakly selected loci. The latter limit allows us to characterize coalescence, genetic diversity, and the speed of adaptation in the infinitesimal model of quantitative genetics. PMID:24019480

Neher, Richard A; Kessinger, Taylor A; Shraiman, Boris I

2013-09-24

55

Sexual conflict and the gender load: correlated evolution between population fitness and sexual dimorphism in seed beetles  

PubMed Central

Although males and females share much of the same genome, selection is often distinct in the two sexes. Sexually antagonistic loci will in theory cause a gender load in populations, because sex-specific selection on a given trait in one sex will compromise the adaptive evolution of the same trait in the other sex. However, it is currently not clear whether such intralocus sexual conflict (ISC) represents a transient evolutionary state, where conflict is rapidly resolved by the evolution of sexual dimorphism (SD), or whether it is a more chronic impediment to adaptation. All else being equal, ISC should manifest itself as correlated evolution between population fitness and SD in traits expressed in both sexes. However, comparative tests of this prediction are problematic and have been unfeasible. Here, we assess the effects of ISC by comparing fitness and SD across distinct laboratory populations of seed beetles that should be well adapted to a shared environment. We show that SD in juvenile development time, a key life-history trait with a history of sexually antagonistic selection in this model system, is positively related to fitness. This effect is due to a correlated evolution between population fitness and development time that is positive in females but negative in males. Loosening the genetic bind between the sexes has evidently allowed the sexes to approach their distinct adaptive peaks. PMID:20031994

Arnqvist, Göran; Tuda, Midori

2010-01-01

56

Sexual Segregation in Juvenile New Zealand Sea Lion Foraging Ranges: Implications for Intraspecific Competition, Population Dynamics and Conservation  

PubMed Central

Sexual segregation (sex differences in spatial organisation and resource use) is observed in a large range of taxa. Investigating causes for sexual segregation is vital for understanding population dynamics and has important conservation implications, as sex differences in foraging ecology may affect vulnerability to area-specific human activities. Although behavioural ecologists have proposed numerous hypotheses for this phenomenon, the underlying causes of sexual segregation are poorly understood. We examined the size-dimorphism and niche divergence hypotheses as potential explanations for sexual segregation in the New Zealand (NZ) sea lion (Phocarctos hookeri), a nationally critical, declining species impacted by trawl fisheries. We used satellite telemetry and linear mixed effects models to investigate sex differences in the foraging ranges of juvenile NZ sea lions. Male trip distances and durations were almost twice as long as female trips, with males foraging over the Auckland Island shelf and in further locations than females. Sex was the most important variable in trip distance, maximum distance travelled from study site, foraging cycle duration and percent time at sea whereas mass and age had small effects on these characteristics. Our findings support the predictions of the niche divergence hypothesis, which suggests that sexual segregation acts to decrease intraspecific resource competition. As a consequence of sexual segregation in foraging ranges, female foraging grounds had proportionally double the overlap with fisheries operations than males. This distribution exposes female juvenile NZ sea lions to a greater risk of resource competition and bycatch from fisheries than males, which can result in higher female mortality. Such sex-biased mortality could impact population dynamics, because female population decline can lead to decreased population fecundity. Thus, effective conservation and management strategies must take into account sex differences in foraging behaviour, as well as differential threat-risk to external impacts such as fisheries bycatch. PMID:23028978

Leung, Elaine S.; Chilvers, B. Louise; Nakagawa, Shinichi; Moore, Antoni B.; Robertson, Bruce C.

2012-01-01

57

Evaluation of the potential for sexual reproduction in field populations of Cercospora beticola from USA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cercospora leaf spot, caused by the hemibiotrophic fungal pathogen Cercospora beticola, is the most economically damaging foliar disease of sugarbeet worldwide. Although most C. beticola populations display characteristics reminiscent of sexual recombination, no teleomorph has been described. To ass...

58

Quantifying the gender load: can population crosses reveal interlocus sexual conflict?  

E-print Network

Quantifying the gender load: can population crosses reveal interlocus sexual conflict? Tristan A. F conflict; sperm competition; gender load; intersexual coevolution; speciation; reproductive divergence sequence change for repro- ductive traits in several animal species (Rice & Holland 1997; Rice 1998

Montgomerie, Bob

59

Population-based sexual behavior surveys in China: Liuzhou compared with other prefectural cities  

PubMed Central

Sexual behaviors in China are rapidly changing; simultaneously, STI/HIV prevalence is increasing in the general population. To investigate these major shifts, we examined sexual behaviors and self-reported sexually transmitted infections (STI) in one prefectural city in southern China, Liuzhou, and compared it to other prefectural cities throughout China. We used adults age 18-39 from two sets of population-based surveys that paralleled each other in both content and method. The first set was the Liuzhou survey conducted in 2008 (n=398). The second set consisted of two national surveys collected in 2006 and 2010 (n=2186). Liuzhou respondents reported more active social and sexual behaviors than their national counterparts, including more socializing, dancing, drinking excessively, sexual activity among never married men and women, purchasing commercial sex among men, one-night stands among men, multiple sexual partnerships and self-reported STI among both men and women. Women in Liuzhou reported greater sexual risk behavior than their national counterparts, although overall they reported less than their male counterparts; they were also more likely to have had an abortion than women in other prefectural cities. Our findings provide a comprehensive overview of the sexual context of Liuzhou among the general population, which may help explain the greater STI/HIV prevalence in Liuzhou. PMID:24174289

Yingying, Huang; Abler, Laurie; Suiming, Pan; Henderson, Gail E.; Xin, Wang; Xingliang, Yao; Parish, William L.

2013-01-01

60

Reproduction and sexual dimorphism in a population of Virginia Striatula Linnaeus (Reptilia, Colubridae  

E-print Network

REPRODUCTION AND SEXUAL DIMORPHISM IN A POPULATION- OF VIRGINIA STRIATULA LINNAEUS (REPTILIA& COLUBRIDAE) A Thesis By DONALD RAY CLARK, JR Submitted to the Graduate College of the Texas ARM University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE May, 1964 Major Subject: Wildlife Management REPRODUCTION AND SEXUAL DIMORPHISM IN A POPULATION OF VIRGINIA STRIATULA LINNAEUS (REPTILIA~ COLUBRIDAE) A Thesis By DONALD RAY CLARK& JR ~ Approved...

Clark, Donald Ray

1964-01-01

61

Measuring Immigration and Sexual Reproduction in Field Populations of Mycosphaerella graminicola  

Microsoft Academic Search

Zhan, J., Mundt, C. C., and McDonald, B. A. 1998. Measuring immigration and sexual reproduction in field populations of Mycosphaerella grami- nicola. Phytopathology 88:1330-1337. A field experiment was conducted to determine the relative contribu- tions of immigration and sexual reproduction to the genetic structure of Mycosphaerella graminicola populations during the course of an epidemic. The genetic structure of M. graminicola

J. Zhan; C. C. Mundt; B. A. McDonald

1998-01-01

62

Long-term decline in a red-winged blackbird population: ecological causes and sexual  

E-print Network

Long-term decline in a red-winged blackbird population: ecological causes and sexual selection in an Ontario red-winged blackbird (Agelaius phoeniceus) population using 16 years of data collected between into the study population, also declined substantially. Correlation between blackbirds and hay may

Weatherhead, Patrick J.

63

Genetic differences among populations in sexual dimorphism: evidence for selection on males in a dioecious plant  

PubMed Central

Genetic variation among populations in the degree of sexual dimorphism may be a consequence of selection on one or both sexes. We analysed genetic parameters from crosses involving three populations of the dioecious plant Silene latifolia, which exhibits sexual dimorphism in flower size, to determine whether population differentiation was a result of selection on one or both sexes. We took the novel approach of comparing the ratio of population differentiation of a quantitative trait (QST) to that of neutral genetic markers (FST) for males vs. females. We attributed 72.6% of calyx width variation in males to differences among populations vs. only 6.9% in females. The QST/FST ratio was 4.2 for males vs. 0.4 for females, suggesting that selection on males is responsible for differentiation among populations in calyx width and its degree of sexual dimorphism. This selection may be indirect via genetic correlations with other morphological and physiological traits. PMID:21401772

YU, Q.; ELLEN, E. D.; WADE, M. J.; DELPH, L. F.

2011-01-01

64

On the Genealogy of Large Populations  

Microsoft Academic Search

A new Markov chain is introduced which can be used to describe the family relationships among n individuals drawn from a particular generation of a large haploid population. The properties of this process can be studied, simultaneously for all n, by coupling techniques. Recent results in neutral mutation theory are seen as consequences of the genealogy described by the chain.

J. F. C. KINGMAN

65

Characteristics of victims of sexual abuse by gender and race in a community corrections population.  

PubMed

The purpose of this study was to examine how victims of sexual abuse in a community corrections population differ as a result of their sex and race. Of the 19,422 participants, a total of 1,298 (6.7%) reported a history of sexual abuse and were compared with nonabused participants. The sample was analyzed by race-gender groups (White men, White women, African American men, and African American women) using univariate and logistic regression analyses, which were conducted separately for each group. White women were the most likely to report a history of sexual abuse (26.5%), followed by African American women (16.0%), White men (4.0%), and African American men (1.1%). For all groups, histories of suicidal ideation and suicide attempts were associated with a history of sexual abuse. Sexual abuse was associated with substance abuse problems for women but not the men. Cannabis dependence was associated with sexual abuse for the White women while cocaine dependence was associated with sexual abuse for the African American women. Several other variables were associated with sexual abuse for women but not men, including lower education (White women only), a history of violent offenses (White women only), and living in a shelter (African American women only). African American men tended to have higher levels of education; this was the only variable uniquely associated with either male group. Receiving psychiatric medications was associated with sexual abuse for all groups except African American men and a history of sex for drugs was associated with sexual abuse for all groups except White men. Consistent with national sample, women, particularly White women, were more likely to be victims of sexual abuse. The gender-race differences for the sociodemographic factors associated with sexual abuse, particularly the risk of substance abuse for women, suggest the need for tailored interventions for sexual abuse prevention and treatment. PMID:22203627

Clark, C Brendan; Perkins, Adam; McCullumsmith, Cheryl B; Islam, M Aminul; Hanover, Erin E; Cropsey, Karen L

2012-06-01

66

Trends in High-Risk Sexual Behaviors among General Population Groups in China: A Systematic Review  

PubMed Central

Background The objective of this review was to investigate whether Chinese population groups that do not belong to classical high risk groups show an increasing trend of engaging in high-risk sexual behaviors. Methods We systematically searched the English and Chinese literature on sexual risk behaviors published between January 1980 and March 2012 in PubMed and the China National Knowledge Infrastructure (CNKI). We included observational studies that focused on population groups other than commercial sex workers (CSWs) and their clients, and men who have sex with men (MSM) and quantitatively reported one of the following indicators of recent high-risk sexual behavior: premarital sex, commercial sex, multiple sex partners, condom use or sexually transmitted infections (STIs). We used generalized linear mixed model to examine the time trend in engaging in high-risk sexual behaviors. Results We included 174 observational studies involving 932,931 participants: 55 studies reported on floating populations, 73 on college students and 46 on other groups (i.e. out-of-school youth, rural residents, and subjects from gynecological or obstetric clinics and premarital check-up centers). From the generalized linear mixed model, no significant trends in engaging in high-risk sexual behaviors were identified in the three population groups. Discussion Sexual risk behaviors among certain general population groups have not increased substantially. These groups are therefore unlikely to incite a STI/HIV epidemic among the general Chinese population. Because the studied population groups are not necessarily representative of the general population, the outcomes found may not reflect those of the general population. PMID:24236121

Cai, Rui; Richardus, Jan Hendrik; Looman, Caspar W. N.; de Vlas, Sake J.

2013-01-01

67

Sexual selection on song and cuticular hydrocarbons in two distinct populations of Drosophila montana  

PubMed Central

Sexual selection has the potential to contribute to population divergence and speciation. Most studies of sexual selection in Drosophila have concentrated on a single signaling modality, usually either courtship song or cuticular hydrocarbons (CHCs), which can act as contact pheromones. We have examined the relationship between both signal types and reproductive success using F1–3 offspring of wild-collected flies, raised in the lab. We used two populations of the Holarctic species Drosophila montana that represent different phylogeographic clades that have been separate for ca. 0.5 million years (MY), and differ to some extent in both traits. Here, we characterize the nature and identify the targets of sexual selection on song, CHCs, and both traits combined within the populations. Three measures of courtship outcome were used as fitness proxies. They were the probability of mating, mating latency, and the production of rejection song by females, and showed patterns of association with different traits that included both linear and quadratic selection. Courtship song predicted courtship outcome better than CHCs and the signal modalities acted in an additive rather than synergistic manner. Selection was generally consistent in direction and strength between the two populations and favored males that sang more vigorously. Sexual selection differed in the extent, strength, and nature on some of the traits between populations. However, the differences in the directionality of selection detected were not a good predictor of population differences. In addition, a character previously shown to be important for species recognition, interpulse interval, was found to be under sexual selection. Our results highlight the complexity of understanding the relationship between within-population sexual selection and population differences. Sexual selection alone cannot predict differences between populations. PMID:22408728

Veltsos, Paris; Wicker-Thomas, Claude; Butlin, Roger K; Hoikkala, Anneli; Ritchie, Michael G

2012-01-01

68

Evolution of increased phenotypic diversity enhances population performance by reducing sexual harassment in damselflies.  

PubMed

The effect of evolutionary changes in traits and phenotypic/genetic diversity on ecological dynamics has received much theoretical attention; however, the mechanisms and ecological consequences are usually unknown. Female-limited colour polymorphism in damselflies is a counter-adaptation to male mating harassment, and thus, is expected to alter population dynamics through relaxing sexual conflict. Here we show the side effect of the evolution of female morph diversity on population performance (for example, population productivity and sustainability) in damselflies. Our theoretical model incorporating key features of the sexual interaction predicts that the evolution of increased phenotypic diversity will reduce overall fitness costs to females from sexual conflict, which in turn will increase productivity, density and stability of a population. Field data and mesocosm experiments support these model predictions. Our study suggests that increased phenotypic diversity can enhance population performance that can potentially reduce extinction rates and thereby influence macroevolutionary processes. PMID:25034518

Takahashi, Yuma; Kagawa, Kotaro; Svensson, Erik I; Kawata, Masakado

2014-01-01

69

Molecular hyperdiversity and evolution in very large populations  

PubMed Central

The genomic density of sequence polymorphisms critically affects the sensitivity of inferences about ongoing sequence evolution, function, and demographic history. Most animal and plant genomes have relatively low densities of polymorphisms, but some species are hyperdiverse with neutral nucleotide heterozygosity exceeding 5%. Eukaryotes with extremely large populations, mimicking bacterial and viral populations, present novel opportunities for studying molecular evolution in sexually-reproducing taxa with complex development. In particular, hyperdiverse species can help answer controversial questions about the evolution of genome complexity, the limits of natural selection, modes of adaptation, and subtleties of the mutation process. However, such systems have some inherent complications and here we identify topics in need of theoretical developments. Close relatives of the model organisms Caenorhabditis elegans and Drosophila melanogaster provide known examples of hyperdiverse eukaryotes, encouraging functional dissection of resulting molecular evolutionary patterns. We recommend how best to exploit hyperdiverse populations for analysis, for example, in quantifying the impact of non-crossover recombination in genomes and for determining the identity and micro-evolutionary selective pressures on non-coding regulatory elements. PMID:23506466

Cutter, Asher D.; Jovelin, Richard; Dey, Alivia

2014-01-01

70

Poppr: an R package for genetic analysis of populations with mixed (clonal/sexual) reproduction  

Technology Transfer Automated Retrieval System (TEKTRAN)

Poppr is an R package for analysis of population genetic data. It extends the adegenet package and provides several novel tools, particularly with regard to analysis of data from admixed, clonal, and/or sexual populations. Currently, poppr can be used for dominant/codominant and haploid/diploid gene...

71

Prevalence of sexual violence and posttraumatic stress disorder in an urban African-American population.  

PubMed

Sexual violence is prevalent nationally and contributes to psychopathology in the general population. Despite elevated traumatic event exposure among economically disadvantaged urban-dwelling African-Americans, there is insufficient information on lifetime sexual violence exposure and associated psychopathology in this population. In 2008-2009, 1,306 African-Americans from a Detroit household probability sample reported on lifetime rape and sexual assault and past-month and lifetime posttraumatic stress disorder (PTSD). Lifetime sexual violence prevalence was 26.3 % for women and 5.1 % for men. Relative to non-victims, sexual violence victims: reported more other traumatic events; had 4 times greater unadjusted odds of past-month and lifetime PTSD; had 1.6 times greater adjusted odds of lifetime PTSD only after controlling for other traumatic events. Sexual violence was associated with increased risk for lifetime PTSD and exposure to other traumas. Findings highlight a need to screen for sexual violence and PTSD among urban African-Americans. PMID:23686528

Walsh, Kate; Koenen, Karestan C; Aiello, Allison E; Uddin, Monica; Galea, Sandro

2014-12-01

72

Population biology, genetics, and sexual selection in wild ambystomatid salamanders  

Microsoft Academic Search

Ambystomatid salamanders have long served as models in studies investigating the factors influencing sexual selection due, in part, to their diverse mating behaviors and breeding strategies. However, our current knowledge regarding rates of multiple mating, individual reproductive success, and inbreeding depression is very sparse or lacking altogether in most species. Thus, in this dissertation I used molecular genetic analyses to

Rod N Williams

2007-01-01

73

Gender Differences in Sexual Attitudes and Behaviors: A Review of Meta-Analytic Results and Large Datasets  

Microsoft Academic Search

Gender differences in sexual attitudes and behaviors are typically believed to be large, yet recent evidence suggests that some gender differences in sexuality are much smaller than common knowledge would suggest. This article reviews gender differences in sexual attitudes and behaviors as reported by major meta-analyses and large datasets. In particular, this article reviews gender differences in heterosexual intercourse, masturbation,

Jennifer L. Petersen; Janet Shibley Hyde

2011-01-01

74

High rates of sexual behavior in the general population: correlates and predictors.  

PubMed

We studied 2450, 18-60-year-old men and women from a 1996 national survey of sexuality and health in Sweden to identify risk factors and correlates of elevated rates of sexual behavior (hypersexuality) in a representative, non-clinical population. Interviews and questionnaires measured various sexual behaviors, developmental risk factors, behavioral problems, and health indicators. The results suggested that correlates of high rates of intercourse were mostly positive, whereas the correlates of high rates of masturbation and impersonal sex were typically undesirable. For both men and women, high rates of impersonal sex were related to separation from parents during childhood, relationship instability, sexually transmitted disease, tobacco smoking, substance abuse, and dissatisfaction with life in general. The association between hypersexuality and paraphilic sexual interests (exhibitionism, voyeurism, masochism/sadism) was particularly and equally strong for both genders (odds ratios of 4.6-25.6). The results held, with a few exceptions, when controlling for age, being in a stable relationship, living in a major city, and same-sex sexual orientation. We conclude that elevated rates of impersonal sex are associated with a range of negative health indicators in the general population. PMID:16502152

Långström, Niklas; Hanson, R Karl

2006-02-01

75

On the moulding of senescence by natural selection in sexual and partly sexual populations  

Microsoft Academic Search

Under a wide variety of dynamic environmental conditions, natural selection appears to favor reproductive investment in a\\u000a sexually produced offspring, carrying only half of the mother’s genes, over the investment in an asexually produced offspring,\\u000a genetically identical to her. It is maintained that the same environmental conditions must affect the evolutionary cost and\\u000a benefit of an investment in the prolongation

Ilan Eshel; Beverly Sackler

1990-01-01

76

Quantifying the gender load: can population crosses reveal interlocus sexual conflict?  

PubMed Central

Six sister populations of Drosophila melanogaster kept under identical environmental conditions for greater than 600 generations were reciprocally crossed to investigate the incidence of population divergence in allopatry. Population crosses directly influenced fitness, mating frequency, and sperm competition patterns. Changes in both female remating rate and the outcome of male sperm competition (P1,?P2) in response to foreign males were consistent with intersexual coevolution. Moreover, seven of the 30 crosses between foreign mates resulted in significant reductions in female fitness, whereas two resulted in significant increases, compared to local matings. This tendency for foreign males to reduce female fitness may be interpreted as evidence for either sexually antagonistic coevolution or the disruption of mutualistic interactions. However, instances in which female fitness improved via cohabitation with foreign males may better reveal sexual conflict, signalling release from the cost of interacting with locally adapted males. By this metric, female reproduction in D. melanogaster is strongly constrained by local adaptation by males, a situation that would promote antagonistic coevolution between the sexes. We conclude that sexual selection can promote population differentiation in allopatry and that sexual conflict is likely to have played a role in population differentiation in this study system. PMID:16612894

Long, Tristan A.F; Montgomerie, Robert; Chippindale, Adam K

2006-01-01

77

Population, sexual and reproductive health, rights and sustainable development: forging a common agenda.  

PubMed

This article suggests that sexual and reproductive health and rights activists seeking to influence the post-2015 international development paradigm must work with sustainable development advocates concerned with a range of issues, including climate change, environmental issues, and food and water security, and that a way of building bridges with these communities is to demonstrate how sexual and reproductive health and rights are relevant for these issues. An understanding of population dynamics, including urbanization and migration, as well as population growth, can help to clarify these links. This article therefore suggests that whether or not sexual and reproductive health and rights activists can overcome resistance to discussing "population", become more knowledgeable about other sustainable development issues, and work with others in those fields to advance the global sustainable development agenda are crucial questions for the coming months. The article also contends that it is possible to care about population dynamics (including ageing and problems faced by countries with a high proportion of young people) and care about human rights at the same time. It expresses concern that, if sexual and reproductive health and rights advocates do not participate in the population dynamics discourse, the field will be left free for those for whom respecting and protecting rights may be less of a priority. PMID:24908456

Newman, Karen; Fisher, Sarah; Mayhew, Susannah; Stephenson, Judith

2014-05-01

78

Long-term decline in a red-winged blackbird population: ecological causes and sexual selection consequences.  

PubMed

Habitat loss and large-scale climate phenomena are widely implicated as causing decline in animal populations. I examined how both factors contributed to a precipitous decline in an Ontario red-winged blackbird (Agelaius phoeniceus) population using 16 years of data collected between 1974 and 1995. The decline was manifested as an almost 50% reduction in mean harem size, which reduced the opportunity for sexual selection threefold. Regional hay production, which should affect recruitment into the study population, also declined substantially. Correlation between blackbirds and hay may be coincidental, however, because annual changes in harem size were not associated with annual changes in hay production. This study coincided with an unprecedented positive phase of the North Atlantic Oscillation (NAO). Changes in harem size were correlated with winter NAO index values, suggesting that winter mortality contributed to the population decline. Positive correlation between harem size change and male return rates also supported the winter mortality hypothesis. Continued declines will cause this blackbird population to change from socially polygynous to socially monogamous. Study of red-winged blackbird winter ecology is needed to identify the proximate causes of mortality, whereas breeding studies can explore the consequences of relaxed sexual selection. PMID:16191645

Weatherhead, Patrick J

2005-11-01

79

The role of sexual harassment in cave and surface dwelling populations of the Atlantic molly, Poecilia mexicana (Poeciliidae, Teleostei)  

Microsoft Academic Search

Sexual coercion is a common behaviour for males trying to compensate for being inferior in male competition and\\/or female choice. We measured the cost of male sexual harassment for females as reduced feeding time in three populations of the Atlantic molly ( Poecilia mexicana). Of these populations, one originated from a typical river habitat, another from a lightless cave chamber

Martin Plath; Jakob Parzefall; Ingo Schlupp

2003-01-01

80

Sexual dysfunction: Overview of prevalence, etiological factors, and treatments  

Microsoft Academic Search

Sexual dysfunctions and sexual problems are reviewed from the perspective of prevalence, broad etiological factors, and available treatments. Although a large percentage of individuals experience sexual problems, with estimates between 10% and 52% of men and 25% and 63% of women, the prevalence of sexual dysfunctions that meet diagnostic criteria is lower and less well established by large scale population?based

Julia R. Heiman

2002-01-01

81

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

PubMed

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

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

2009-03-01

82

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

PubMed Central

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

2012-01-01

83

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

Microsoft Academic Search

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

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

2009-01-01

84

Density-dependent sexual reproduction in natural populations of the rotifer asplanchna girodi  

Microsoft Academic Search

The monogonont rotifer Asplanchna girodi was continuously present in daily and bi-daily plankton samples of Golf Course Pond during the spring of 1977. Two cycles of sexual reproduction occurred during this period. By isolation and culture of females it was possible to determine the reproductive type of collected individuals. Data thus obtained suggest that environmental cues associated with population density

Charles E. King; Terry W. Snell

1980-01-01

85

The Exclusion of Intimacy in the Sexuality of the Contemporary College-Age Population.  

ERIC Educational Resources Information Center

Asserts that heterosexual sexual involvement in the contemporary college population is often sporadic, episodic, without commitment, and accompanied by deliberate effort of both partners to suppress tender, romantic feelings and intimacy. Suggests the sources of this situation lie in changes in the ethos, the ascent of women, advances in…

Cobliner, W. Godfrey

1988-01-01

86

Among-population variation and correlations in sexually dimorphic traits of Silene latifolia  

Microsoft Academic Search

The degree of sexual dimorphism in a trait may be determined directly by disruptive selection, as well as by correlations with other traits under selection. We grew seeds from nine populations of the dioecious plant Silene latifolia in a common-garden experiment to determine whether phenotypic variation and correlations existed for floral, leaf and resource allocation traits, and whether this variation

L. F. DELPH; F. N. KNAPCZYK; D. R. TAYLOR

2002-01-01

87

Differential costs of sexual and vegetative reproduction in wild strawberry populations  

Microsoft Academic Search

The CO2 costs of producing sexual and vegetative reproductive propagules were calculated for two species of wild strawberry, Fragaria virginiana and F. vesca. Five populations on sites representing a gradient of successional regrowth near Ithaca, New York, USA, were studied for two or three years each. Field studies of phenology, biomass, demography, and environment and laboratory studies of CO2 exchange

Thomas W. Jurik

1985-01-01

88

Sexual violence and neonatal outcomes: a Norwegian population-based cohort study  

PubMed Central

Objective The objective of this study was to explore the association between sexual violence and neonatal outcomes. Design National cohort study. Setting Women were recruited to the Norwegian Mother and Child Cohort Study (MoBa) while attending routine ultrasound examinations from 1999 to 2008. Population A total of 76?870 pregnant women. Methods Sexual violence and maternal characteristics were self-reported in postal questionnaires during pregnancy. Neonatal outcomes were retrieved from the Medical Birth Registry of Norway (MBRN). Risk estimations were performed with linear and logistic regression analysis. Outcome measures: gestational age at birth, birth weight, preterm birth (PTB), low birth weight (LBW) and small for gestational age (SGA). Results Of 76?870 women, 18.4% reported a history of sexual violence. A total of 4.7% delivered prematurely, 2.7% had children with a birth weight <2500?g and 8.1% children were small for their gestational age. Women reporting moderate or severe sexual violence (rape) had a significantly reduced gestational length (2?days) when the birth was provider-initiated in an analysis adjusted for age, parity, education, smoking, body mass index and mental distress. Those exposed to severe sexual violence had a significantly reduced gestational length of 0.51?days with a spontaneous start of birth. Crude estimates showed that severe sexual violence was associated with PTB, LBW and SGA. When controlling for the aforementioned sociodemographic and behavioural factors, the association was no longer significant. Conclusions Sexual violence was not associated with adverse neonatal outcomes. Moderate and severe violence had a small but significant effect on gestational age; however, the clinical influence of this finding is most likely limited. Women exposed to sexual violence in this study reported more of the sociodemographic and behavioural factors associated with PTB, LBW and SGA compared with non-abused women. PMID:25763796

Henriksen, Lena; Schei, Berit; Vangen, Siri; Lukasse, Mirjam

2014-01-01

89

Sensation Seeking and Impulsivity: Combined Associations with Risky Sexual Behavior in a Large Sample of Young Adults  

Microsoft Academic Search

Although prior studies have shown that sensation seeking and impulsive decision-making are related to sexual risk-taking, it is still unclear whether these personality traits operate independently or synergistically. The purpose of this study was to elucidate the joint contribution of these personality traits to HIV and sexually transmitted disease (STD) risk behaviors using data from a large sample of sexually

Richard Charnigo; Seth M. Noar; Christopher Garnett; Richard Crosby; Philip Palmgreen; Rick S. Zimmerman

2012-01-01

90

Genetic differences among populations in sexual dimorphism: evidence for selection on males in a dioecious plant.  

PubMed

Genetic variation among populations in the degree of sexual dimorphism may be a consequence of selection on one or both sexes. We analysed genetic parameters from crosses involving three populations of the dioecious plant Silene latifolia, which exhibits sexual dimorphism in flower size, to determine whether population differentiation was a result of selection on one or both sexes. We took the novel approach of comparing the ratio of population differentiation of a quantitative trait (Q(ST) ) to that of neutral genetic markers (F(ST) ) for males vs. females. We attributed 72.6% of calyx width variation in males to differences among populations vs. only 6.9% in females. The Q(ST) /F(ST) ratio was 4.2 for males vs. 0.4 for females, suggesting that selection on males is responsible for differentiation among populations in calyx width and its degree of sexual dimorphism. This selection may be indirect via genetic correlations with other morphological and physiological traits. PMID:21401772

Yu, Q; Ellen, E D; Wade, M J; Delph, L F

2011-05-01

91

Large-Scale Age-Dependent Skewed Sex Ratio in a Sexually Dimorphic Avian Scavenger  

PubMed Central

Age-dependent skewed sex ratios have been observed in bird populations, with adult males generally outnumbering females. This trend is mainly driven by higher female mortality, sometimes associated with anthropogenic factors. Despite the large amount of work on bird sex ratios, research examining the spatial stability of adult sex ratios is extremely scarce. The Andean condor (Vultur gryphus) is the only bird of prey with strong sexual dimorphism favouring males (males are 30% heavier than females). By examining data from most of its South-American range, we show that while the juvenile sex ratio is balanced, or even female-skewed, the sex ratio becomes increasing male-skewed with age, with adult males outnumbering females by >20%, and, in some cases by four times more. This result is consistent across regions and independent of the nature of field data. Reasons for this are unknown but it can be hypothesized that the progressive disappearance of females may be associated with mortality caused by anthropogenic factors. This idea is supported by the asymmetric habitat use by the two sexes, with females scavenging in more humanized areas. Whatever the cause, male-skewed adult sex ratios imply that populations of this endangered scavenger face higher risks of extinction than previously believed. PMID:23029488

Lambertucci, Sergio A.; Carrete, Martina; Donázar, José Antonio; Hiraldo, Fernando

2012-01-01

92

Multivariate analysis of the sexual dimorphism of the hip bone in a modern human population and in early hominids.  

PubMed

A large sample of hip bones of known sex coming from one modern population is studied morphologically and by multivariate analysis to investigate sexual dimorphism patterns. A principal component analysis of raw data shows that a large amount of the hip bone sexual dimorphism is accounted for by size differences, but that sex-linked shape variation is also very conspicuous and cannot be considered an allometric consequence of differences in body size between the sexes. The PCA of transformed ("shape") variables indicates that the female hip bones are different in those traits associated with a relatively larger pelvic inlet (longer pubic bones, a greater degree of curvature of the iliopectineal line, and more posterior position of the auricular surface), as well as a broader sciatic notch. The analysis of nonmetric traits also shows marked sexual dimorphism in the position of the sacroiliac joint in the iliac bone, in the shape of the sciatic notch, in pubic morphology, and in the presence of the pre-auricular sulcus in females. When the australopithecine AL 288-1 and Sts 14 hip bones are included in the multivariate analysis, they appear as "ultra-females." In particular these early hominids exhibit extraordinarily long pubic bones and iliopectineal lines, which cannot be explained by allometry. PMID:8147439

Arsuaga, J L; Carretero, J M

1994-02-01

93

Religiosity and Risky Sexual Behaviors among an African American Church-based Population  

PubMed Central

African Americans are disproportionately burdened by STDs and HIV in the US. This study examined the relationships between demographics, religiosity, and sexual risk behaviors among 255 adult African American church-based participants. Although participants were highly religious, they reported an average of seven lifetime sex partners and most inconsistently used condoms. Several demographic variables and religiosity significantly predicted lifetime HIV-related risk factors. Taken together, findings indicated that this population is at risk for HIV. Future research should continue to identify correlates of risky sexual behavior among African American parishioners to facilitate the development of HIV risk reduction interventions in their church settings. PMID:23054481

Hawes, Starlyn M.; Berkley-Patton, Jannette Y.

2014-01-01

94

Sexual Orientation and Mental and Physical Health Status: Findings From a Dutch Population Survey  

PubMed Central

Objectives. We sought to determine whether sexual orientation is related to mental and physical health and health behaviors in the general population. Methods. Data was derived from a health interview survey that was part of the second Dutch National Survey of General Practice, carried out in 2001 among an all-age random sample of the population. Of the 19685 persons invited to participate, 65% took part in the survey. Sexual orientation was assessed in persons aged 18 years and older and reported by 98.2% of 9684 participants. The respondents’ characteristics are comparable with those of the Dutch general population. Results. Gay/lesbian participants reported more acute mental health symptoms than heterosexual people and their general mental health also was poorer. Gay/lesbian people more frequently reported acute physical symptoms and chronic conditions than heterosexual people. Differences in smoking, alcohol use, and drug use were less prominent. Conclusions. We found that sexual orientation was associated with mental as well as physical health. The causal processes responsible for these differences by sexual orientation need further exploration. PMID:16670235

Sandfort, Theo G.M.; Bakker, Floor; Schellevis, François G.; Vanwesenbeeck, Ine

2006-01-01

95

Evolution of Population with Sexual and Asexual Reproduction in Changing Environment  

NASA Astrophysics Data System (ADS)

Using a lattice model based on Monte Carlo simulations, we study the role of the reproduction pattern on the fate of an evolving population. Each individual is under the selection pressure from the environment and random mutations. The habitat ("climate") is changing periodically. Evolutions of populations following two reproduction patterns are compared, asexual and sexual. We show, via Monte Carlo simulations, that sexual reproduction by keeping more diversified populations gives them better chances to adapt themselves to the changing environment. However, in order to obtain a greater chance to mate, the birth rate should be high. In the case of low birth rate and high mutation probability there is a preference for the asexual reproduction.

He, Mingfeng; Yu, Changliang; Ruan, Hongbo; Yao, Lei

96

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

97

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

Microsoft Academic Search

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

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

2004-01-01

98

Getting the timing right: antler growth phenology and sexual selection in a wild red deer population  

Microsoft Academic Search

There has been growing interest in the determinants of the annual timing of biological phenomena, or phenology, in wild populations,\\u000a but research on vertebrate taxa has primarily focused on the phenology of reproduction. We present here analyses of the phenology\\u000a of the annual growth of a secondary sexual characteristic, antlers in red deer (Cervus elaphus) males. The long-term individual-based data

Michelle N. Clements; Tim H. Clutton-Brock; Steve D. Albon; Josephine M. Pemberton; Loeske E. B. Kruuk

2010-01-01

99

Child sexual abuse in southern Brazil and associated factors: a population-based study  

PubMed Central

Background The prevalence of child sexual abuse (CSA) in the population has been poorly described in developing countries. Population data on child sexual abuse in Brazil is very limited. This paper aims to estimate lifetime prevalence of child sexual abuse and associated factors in a representative sample of the population aged 14 and over in a city of southern Brazil. Methods A two-stage sampling strategy was used and individuals were invited to respond to a confidential questionnaire in their households. CSA was defined as non-consensual oral-genital, genital-genital, genital-rectal, hand-genital, hand-rectal, or hand-breast contact/intercourse between ages 0 and 18. Associations between socio-demographic variables and CSA, before and after age 12, were estimated through multinomial regression. Results Complete data were available for 1936 respondents from 1040 households. Prevalence of CSA among girls (5.6% 95%CI [4.8;7.5]) was higher than among boys (1.6% 95%CI [0.9;2.6]). Boys experienced CSA at younger ages than girls and 60% of all reported CSA happened before age 12. Physical abuse was frequently associated with CSA at younger (OR 5.6 95%CI [2.5;12.3]) and older (OR 9.4 95%CI [4.5;18.7]) ages. CSA after age 12 was associated with an increased number of sexual partners in the last 2 months. Conclusion Results suggest that CSA takes place at young ages and is associated with physical violence, making it more likely to have serious health and developmental consequences. Except for gender, no other socio-demographic characteristic identified high-risk sub-populations. PMID:19432975

Bassani, Diego G; Palazzo, Lilian S; Béria, Jorge U; Gigante, Luciana P; Figueiredo, Andréia CL; Aerts, Denise RGC; Raymann, Beatriz CW

2009-01-01

100

Sexual Selection by Male Choice in Monogamous and Polygynous Human Populations  

Microsoft Academic Search

The theoretical possibility of coevolution of a viability-reducing female physical trait and a male mating preference for that trait by Fisherian sexual selection in monogamous and polygynous populations is demonstrated using two-locus haploid models. It is assumed that there is dichotomous variation in male resources, resource-rich males have a wider choice among females than resource-poor males, and a female has

Yasuo Ihara; Kenichi Aoki

1999-01-01

101

The Group-Level Consequences of Sexual Conflict in Multigroup Populations  

PubMed Central

In typical sexual conflict scenarios, males best equipped to exploit females are favored locally over more prudent males, despite reducing female fitness. However, local advantage is not the only relevant form of selection. In multigroup populations, groups with less sexual conflict will contribute more offspring to the next generation than higher conflict groups, countering the local advantage of harmful males. Here, we varied male aggression within-and between-groups in a laboratory population of water striders and measured resulting differences in local population growth over a period of three weeks. The overall pool fitness (i.e., adults produced) of less aggressive pools exceeded that of high aggression pools by a factor of three, with the high aggression pools essentially experiencing no population growth over the course of the study. When comparing the fitness of individuals across groups, aggression appeared to be under stabilizing selection in the multigroup population. The use of contextual analysis revealed that overall stabilizing selection was a product of selection favoring aggression within groups, but selected against it at the group-level. Therefore, this report provides further evidence to show that what evolves in the total population is not merely an extension of within-group dynamics. PMID:22039491

Eldakar, Omar Tonsi; Gallup, Andrew C.

2011-01-01

102

Supporting Information "Sexual Reproduction Reshapes the Genetic Architecture of Digital Organisms"  

E-print Network

1 Supporting Information "Sexual Reproduction Reshapes the Genetic Architecture of Digital large genomes. Out of the 100 populations with each reproductive mode, 35 sexual populations evolved populations did so. These very large genomes typically evolved via genome doublings, and sexual reproduction

Ofria, Charles A.

103

The Impact of Aging on Sexual Function and Sexual Dysfunction in Women: A Review of Population-Based Studies  

Microsoft Academic Search

Introduction. Scientific interest in the impact of aging on women's sexual function and dysfunction has increased in the half century since Kinsey described age-related changes in women's sexual activities. However, a range of methodological issues limit the conclusions that can be drawn from many published studies in this area. Aim. To review community-based studies investigating changes in women's sexual function

Richard Hayes; Lorraine Dennerstein

2005-01-01

104

Sexual assault while too intoxicated to resist: a general population study of Norwegian teenage girls  

PubMed Central

Background Underage drinking is widespread, but studies on alcohol-related sexual victimization among teenage girls are almost non-existent. Research on individual correlates and risk factors of sexual victimization more generally is also meager. This study focuses on sexual assault while incapacitated due to drunkenness among 15–18 year-old girls and examines how age, drinking behavior, impulsivity and involvement in norm-violating activities are associated with such victimization experiences. Methods Data stemmed from a school survey (response rate: 85%) in 16 Norwegian municipalities. Almost all analyses were restricted to girls who had been intoxicated in the past year (n?=?2701). In addition to bivariate associations, adjusted odds ratios and relative risks of incapacitated sexual assault (ISA) were estimated. Further, population-attributable fractions were calculated to explore how the prevalence of ISA victimization was likely to be affected if effective preventive measures were targeted solely at high-risk groups. Results The majority of the girls (71%) had been intoxicated in the past year, of which 7% had experienced ISA victimization in the same period. The proportion of victims decreased by age within the group that had been intoxicated, reflecting that the youngest girls were more likely to get severely drunk. Impulsivity and involvement in norm-violating behaviors were identified as potential risk factors, but the population-attributable fractions indicated that the groups with the highest risk of ISA victimization accounted for only a minority of all the cases of such victimization. Conclusion Sexual assault against teenage girls who are too drunk to resist seems to be prevalent in Norway – notably among the youngest girls who engage in heavy episodic drinking. This study also suggests that one should reconsider the notion that no individual attributes are related to females’ sexual assault victimization. It also indicates that a high risk approach to prevention, targeting groups with a high level of impulsivity or behavioral problems, may have limited effect on the prevalence of ISA victimization. Thus, from a public health perspective, it may be advisable to give priority to universal preventive measures to curb young girls’ risk of being sexually assaulted in a state of alcohol-induced incapacitation. PMID:24774966

2014-01-01

105

Evolutionary divergence in sexual signals: Insights from within and among barn swallow populations  

NASA Astrophysics Data System (ADS)

A wealth of studies across diverse animal groups indicate the importance of sexual selection in shaping phenotypes within and across breeding populations. In recent decades, much research has focused on how divergent sexual selection pressures among populations may lead to speciation. For my first dissertation chapter, I performed a literature review on the causes and consequences of evolutionary divergence in acoustic signals and developed the acoustic window conceptual framework for understanding the contributions of selection, genetic drift, and evolutionary constraint to signal divergence. Further, I found that sexual selection explains acoustic differences between recently diverged populations of the best-studied taxa. However, the relative contributions of ecological selection, sexual selection, and drift to acoustic divergence have not typically been considered within the same study systems. The remainder of my dissertation used the Northern Hemisphere-distributed barn swallow ( Hirundo rustica) species complex as a model system to study sender-receiver dynamics, intra- and intersexual selection pressures, and visual and acoustic signal interactions at the local scale, and signal divergence across populations at the global scale. From song recordings taken across 19 sampling sites, spanning five of six described subspecies, I demonstrated considerable conservation in song structure. However, temporal traits were highly divergent across subspecies, and in particular, the speed of the terminal trill of songs. In a detailed study of the multimodal communication system of the barn swallow (including visual and acoustic traits), I demonstrated that males and females use different types of signals to mediate competition and mate choice. One of the only exceptions to this rule was trill rate, which was also implicated in song divergence across populations. In order to test the function of trill rate in communication, I performed a two-year playback study within the North American subspecies, H. r. erythrogaster. Contrary to expectations, males did not have stronger responses to faster trilling (high performance) simulated intruders. Instead, resident males had stronger responses to the high performance stimulus only when the intruder was also darker than the resident. Collectively, my dissertation offers novel insight into the evolutionary dynamics of complex sexual signaling at multiple spatial scales.

Wilkins, Matthew Reed

106

Computational Methods for Learning Population History from Large Scale Genetic  

E-print Network

Computational Methods for Learning Population History from Large Scale Genetic Variation Datasets of Philosophy. Copyright 2013 Ming-Chi Tsai #12;Keywords: Population Genetics, Minimum Description Length is a fundamental question in population genetics with numerous implications for basic and applied research

Matsuda, Noboru

107

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

PubMed

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

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

2014-06-01

108

Rapid evolution of a sexually selected trait following population establishment in a novel habitat.  

PubMed

Colonization of novel environments creates new selection pressures. Sexually selected traits are affected by the physical and social environment and should be especially susceptible to change, but this has rarely been studied. In southern California, dark-eyed juncos, (Junco hyemalis) naturally breed in mixed-coniferous temperate forests, typically from 1500 m to 3000 m in elevation. In the early 1980s, a small population became established in a coastal habitat, the University of California, San Diego campus, which has a mild, Mediterranean climate. I show that a sexually and socially selected signaling trait--the amount of white in the tail--has declined by approximately 22% as compared to mountain juncos. I address three main factors that could explain the difference between mountain and coastal juncos: phenotypic plasticity, genetic drift, and selection. Results indicate that the first two can be ruled out as the sole cause of the plumage change, which implies that selection contributed to the genetic differentiation from the mountain population. The estimated rate of evolution is about 0.2 haldanes, comparable with rates of change in systems where individuals have been artificially introduced into new environments (e.g., guppies and Drosophila). This is the first study to demonstrate evolution of a sexually selected trait after only several generations resulting from a natural invasion into a novel environment. PMID:15058729

Yeh, Pamela J

2004-01-01

109

The Speed of Adaptation in Large Asexual Populations  

Microsoft Academic Search

In large asexual populations, beneficial mutations have to compete with each other for fixation. Here, I derive explicit analytic expressions for the rate of substitution and the mean beneficial effect of fixed mutations, under the assumptions that the population size N is large, that the mean effect of new beneficial mutations is smaller than the mean effect of new deleterious

Claus O. Wilke

2004-01-01

110

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

PubMed Central

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

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

2009-01-01

111

Childhood sexual abuse and abnormal personality: a population-based study  

PubMed Central

Background Childhood sexual abuse (CSA) has been shown to be a risk factor for personality disorder (PD). However, no previous studies have examined whether associations exist between sexual abuse and abnormal personality as measured both categorically and dimensionally. Such enquiry would more fully illuminate the impact of CSA on adult personality. Method Using a large nationally representative sample, we set out to examine associations between CSA and categorically defined PD. We also examined associations between CSA and the five dimensions of personality (openness to experience, conscientiousness, extraversion, agreeableness and neuroticism). A total of 1520 young adults were interviewed to determine the prevalence of sexual abuse occurring before age 16 years. A dimensional measure of personality was completed by 1469 participants, and 1145 had an informant-based PD assessment. Results PD was independently associated with repeated CSA [fully adjusted odds ratio (OR) 1.9, 95% confidence interval (CI) 1.1–3.4]. Repeated sexual abuse was also associated with higher neuroticism and lower agreeableness (p values for both <0.001). Adjusting for the effects of potential confounders and mediators, including earlier symptoms of anxiety and depression, had little impact on the strength of associations. Conclusions We conclude that repeated CSA is independently associated with categorically defined PD, and also with higher neuroticism and lower agreeableness. Our findings suggest that if a dimensional classification of PDs is adopted in future classification systems, there might be meaningful continuity with previous aetiological research conducted using the current categorical system. PMID:20868539

Moran, P.; Coffey, C.; Chanen, A.; Mann, A.; Carlin, J. B.; Patton, G. C.

2011-01-01

112

Common features of sexual dimorphism in the cranial airways of different human populations.  

PubMed

Sexual dimorphism in the human craniofacial system is an important feature of intraspecific variation in recent and fossil humans. Although several studies have reported different morphological patterns of sexual dimorphism in different populations, this study searches for common morphological aspects related to functional anatomy of the respiratory apparatus. 3D geometric morphometrics were used to test the hypothesis that due to higher daily energy expenditure and associated greater respiratory air consumption as well as differences in body composition, males should have absolutely and relatively greater air passages in the bony cranial airways than females. We measured 25 3D landmarks in five populations (N = 212) of adult humans from different geographic regions. Male average cranial airways were larger in centroid sizes than female ones. Males tended to show relatively taller piriform apertures and, more consistently, relatively taller internal nasal cavities and choanae than females. Multivariate regressions and residual analysis further indicated that after standardizing to the same size, males still show relatively larger airway passages than females. Because the dimensions of the choanae are limiting factors for air transmission towards the noncranial part of the respiratory system, the identified sex-specific differences in cranial airways, possibly shared among human populations, may be linked with sex-specific differences in body size, composition, and energetics. These findings may be important to understanding trends in hominin facial evolution. PMID:21994017

Bastir, Markus; Godoy, Paula; Rosas, Antonio

2011-11-01

113

Validity of Physiological Measures of Pedophilic Sexual Arousal in a Sexual Offender Population: A Critique of Hall, Proctor, and Nelson  

Microsoft Academic Search

It is argued that methodological problems in Hall, Proctor, and Nelson’s (1988) comparison of phallometric data on child molesters and rapists include confounding of stimulus category and duration, omission of neutral stimuli and a normal control group, failure to employ relative measures of sexual preference, and failure to exclude subjects who did not respond to the sexual stimuli. Quinsey and

Vernon L. Quinsey; D. R. Laws

1990-01-01

114

Introducing Human Sexuality into the Population Education Curriculum. The State-of-the-Art. Population Education Research Utilization Monograph Series 1 Part 3.  

ERIC Educational Resources Information Center

This paper explores one problem area that hampers the introduction and acceptance of sex education in schools. Specifically, the paper reviews problems related to the human sexuality component of population education programs in the Philippines. Research on the experiences of the Population Education Program (PEP) is discussed, as well as research…

Villanueva, Carmelita L.; Arellano-Reyes, Ma. Felicitas

115

Prevalence and predictors of concurrent sexual partnerships in a predominantly African American population in Jackson, Mississippi.  

PubMed

Concurrent sexual partnerships, or sexual partnerships that overlap in time, have been associated with HIV and sexually transmitted infections (STI). How best to measure concurrency and the personal characteristics and predictors of concurrency are not yet well understood. We compared two frequently used concurrency definitions, including a self-reported measure based on participant response regarding overlapping sex with partners, and the UNAIDS measure based on overlapping dates of last sex and intention to have sex again. We performed multivariable logistic regression analyses to identify socio-demographic, behavioral, and structural predictors of concurrency among 1,542 patients at an urban STI clinic in Jackson, Mississippi. Nearly half (44 %) reported concurrency based on self-reported sex with other partners, and 26 % reported concurrency according to the UNAIDS concurrency measure. Using the self-reported concurrency measure, the strongest predictors of concurrency were perceived partner concurrency, drug use at last sex, having more than 10 lifetime partners, and being recently incarcerated. Strongest predictors of concurrency using the UNAIDS measure were lifetime number of partners and perceived partner concurrency. Concurrency is highly prevalent in this population in the Deep South and social, structural and behavioral factors were important predictors of concurrency for both measures. Future research should use time anchored data collection methods and biomarkers to assess whether both definitions of concurrency are associated with HIV outcomes. PMID:24803130

Nunn, Amy; MacCarthy, Sarah; Barnett, Nancy; Rose, Jennifer; Chan, Philip; Yolken, Annajane; Cornwall, Alexandra; Chamberlain, Nicholas; Barnes, Arti; Riggins, Reginald; Moore, Elya; Simmons, Dantrell; Parker, Sharon; Mena, Leandro

2014-12-01

116

Female sperm limitation in natural populations of a sexual/asexual mating complex (Poecilia latipinna, Poecilia formosa).  

PubMed

In sperm-dependent sexual/asexual mating systems, male mate choice is critical for understanding the mechanisms behind apparent stability observed in natural populations. The gynogenetic Amazon molly (Poecilia formosa) requires sperm from sexual males (e.g. Poecilia latipinna) to trigger embryogenesis, but inheritance is strictly maternal. Consequently, males should try to avoid or reduce the cost of mating with asexuals. We investigated male mate choice by documenting the presence of sperm in natural populations and found that a higher proportion of sexual females had sperm than asexuals. In addition, among those females that had sperm, sexuals had more sperm than asexuals. Our results hint at a role for male mate choice as a stabilizing factor in such systems. PMID:18319207

Riesch, Rüdiger; Schlupp, Ingo; Plath, Martin

2008-06-23

117

Sexual Reproduction Plays a Major Role in the Genetic Structure of Populations of the Fungus Mycosphaerella graminicola  

Microsoft Academic Search

The relative contributions of sexual and asexual reproduction to the genetic structure of populations can be difficult to determine for fungi that use a mixture of both types of propagation. Nuclear RFLPs and DNA fingerprints were used to make indirect and direct measures of departures from random mating in a population of the plant pathogenic fungus Mycosphaerella graminicola during the

Ruey-Shyang Chen; Bruce A. McDonald

1996-01-01

118

Intragenomic conflict in populations infected by Parthenogenesis Inducing Wolbachia ends with irreversible loss of sexual reproduction  

PubMed Central

Background The maternally inherited, bacterial symbiont, parthenogenesis inducing (PI) Wolbachia, causes females in some haplodiploid insects to produce daughters from both fertilized and unfertilized eggs. The symbionts, with their maternal inheritance, benefit from inducing the production of exclusively daughters, however the optimal sex ratio for the nuclear genome is more male-biased. Here we examine through models how an infection with PI-Wolbachia in a previously uninfected population leads to a genomic conflict between PI-Wolbachia and the nuclear genome. In most natural populations infected with PI-Wolbachia the infection has gone to fixation and sexual reproduction is impossible, specifically because the females have lost their ability to fertilize eggs, even when mated with functional males. Results The PI Wolbachia infection by itself does not interfere with the fertilization process in infected eggs, fertilized infected eggs develop into biparental infected females. Because of the increasingly female-biased sex ratio in the population during a spreading PI-Wolbachia infection, sex allocation alleles in the host that cause the production of more sons are rapidly selected. In haplodiploid species a reduced fertilization rate leads to the production of more sons. Selection for the reduced fertilization rate leads to a spread of these alleles through both the infected and uninfected population, eventually resulting in the population becoming fixed for both the PI-Wolbachia infection and the reduced fertilization rate. Fertilization rate alleles that completely interfere with fertilization ("virginity alleles") will be selected over alleles that still allow for some fertilization. This drives the final resolution of the conflict: the irreversible loss of sexual reproduction and the complete dependence of the host on its symbiont. Conclusions This study shows that dependence among organisms can evolve rapidly due to the resolution of the conflicts between cytoplasmic and nuclear genes, and without requiring a mutualism between the partners. PMID:20667099

2010-01-01

119

Population genetics of French brown trout (Salmo trutta L): large geographical differentiation of wild populations  

E-print Network

Population genetics of French brown trout (Salmo trutta L): large geographical differentiation The genetic variability of 7 fish-farm strains and 14 wild populations of brown trout was studied an extreme genetic differentiation in brown trout. UrcNtn clustering analysis subdivided the populations

Paris-Sud XI, Université de

120

Protocol Design for Large-Scale Cross-Sectional Studies of Sexual Abuse and Associated Factors in Individual Sports: Feasibility Study in Swedish Athletics  

PubMed Central

To ensure health and well-being for their athletes, sports organizations must offer preventive measures against sexual abuse. The aim of this study was to design and evaluate feasibility of a research protocol for cross-sectional epidemiological studies of sexual abuse in athletics. Examination of the requirements on the study of sexual abuse in athletics was followed by iterated drafting of protocol specifications and formative evaluations. The feasibility of the resulting protocol was evaluated in a national-level study among elite athletics athletes (n = 507) in Sweden. The definition of sexual abuse, the ethical soundness of the protocol, reference populations and study of co-morbidity, and the means for athlete-level data collection were identified as particularly complex issues in the requirements analyses. The web-based survey defined by the protocol facilitates anonymous athlete self-reporting of data on exposure to sexual abuse. 198 athletes (39%) fully completed the feasibility survey. 89% (n = 177) reported that they agreed with that the questions in the survey were important, and 95% (n = 189) reported that they answered truthfully to all questions. Similarly, 91% (n = 180) reported that they did not agree with that the questions were unpleasant for them. However, 16% (n = 32) reported that they did not find the survey to be of personal value, and 12% (n = 23) reported that the survey had caused them to think about issues that they did not want to think about. Responding that participation was not personally gratifying was associated with training more hours (p = 0.01). There is a scarcity of research on the prevention of sexual abuse in individual sports. The present protocol should be regarded as a means to overcome this shortcoming in athletics. When implementing the protocol, it is necessary to encourage athlete compliance and to adapt the web-based survey to the particular infrastructural conditions in the sports setting at hand. Key points A research protocol for cross-sectional epidemiological studies of sexual abuse in athletics was designed and its feasibility evaluated. The definition of sexual abuse, ethical soundness of the protocol, reference populations and study of co-morbidity, and means for athlete-level data collection were in requirements analyses identified as particularly complex design issues. The feasibility evaluation showed a high non-participation rate (61%), but also that the large majority of participants found the study important and that questions were answered truthfully. Responding that partaking in the study was not personally gratifying was associated with training more hours. When implementing cross-sectional epidemiological studies of sexual abuse in athletics, it is necessary to promote and facilitate athlete participation. PMID:25729306

Timpka, Toomas; Janson, Staffan; Jacobsson, Jenny; Ekberg, Joakim; Dahlström, Örjan; Kowalski, Jan; Bargoria, Victor; Mountjoy, Margo; Svedin, Carl G.

2015-01-01

121

Protocol design for large-scale cross-sectional studies of sexual abuse and associated factors in individual sports: feasibility study in Swedish athletics.  

PubMed

To ensure health and well-being for their athletes, sports organizations must offer preventive measures against sexual abuse. The aim of this study was to design and evaluate feasibility of a research protocol for cross-sectional epidemiological studies of sexual abuse in athletics. Examination of the requirements on the study of sexual abuse in athletics was followed by iterated drafting of protocol specifications and formative evaluations. The feasibility of the resulting protocol was evaluated in a national-level study among elite athletics athletes (n = 507) in Sweden. The definition of sexual abuse, the ethical soundness of the protocol, reference populations and study of co-morbidity, and the means for athlete-level data collection were identified as particularly complex issues in the requirements analyses. The web-based survey defined by the protocol facilitates anonymous athlete self-reporting of data on exposure to sexual abuse. 198 athletes (39%) fully completed the feasibility survey. 89% (n = 177) reported that they agreed with that the questions in the survey were important, and 95% (n = 189) reported that they answered truthfully to all questions. Similarly, 91% (n = 180) reported that they did not agree with that the questions were unpleasant for them. However, 16% (n = 32) reported that they did not find the survey to be of personal value, and 12% (n = 23) reported that the survey had caused them to think about issues that they did not want to think about. Responding that participation was not personally gratifying was associated with training more hours (p = 0.01). There is a scarcity of research on the prevention of sexual abuse in individual sports. The present protocol should be regarded as a means to overcome this shortcoming in athletics. When implementing the protocol, it is necessary to encourage athlete compliance and to adapt the web-based survey to the particular infrastructural conditions in the sports setting at hand. Key pointsA research protocol for cross-sectional epidemiological studies of sexual abuse in athletics was designed and its feasibility evaluated.The definition of sexual abuse, ethical soundness of the protocol, reference populations and study of co-morbidity, and means for athlete-level data collection were in requirements analyses identified as particularly complex design issues.The feasibility evaluation showed a high non-participation rate (61%), but also that the large majority of participants found the study important and that questions were answered truthfully.Responding that partaking in the study was not personally gratifying was associated with training more hours.When implementing cross-sectional epidemiological studies of sexual abuse in athletics, it is necessary to promote and facilitate athlete participation. PMID:25729306

Timpka, Toomas; Janson, Staffan; Jacobsson, Jenny; Ekberg, Joakim; Dahlström, Örjan; Kowalski, Jan; Bargoria, Victor; Mountjoy, Margo; Svedin, Carl G

2015-03-01

122

Synchronization of animal population dynamics by large-scale climate  

Microsoft Academic Search

The hypothesis that animal population dynamics may be synchronized by climate is highly relevant in the context of climate change because it suggests that several populations might respond simultaneously to climatic trends if their dynamics are entrained by environmental correlation. The dynamics of many species throughout the Northern Hemisphere are influenced by a single large-scale climate system, the North Atlantic

Eric Post; Mads C. Forchhammer

2002-01-01

123

The Speed of Adaptation in Large Asexual Populations  

Microsoft Academic Search

In large asexual populations, beneficial mutations have to compete with each\\u000aother for fixation. Here, I derive explicit analytic expressions for the rate\\u000aof substitution and the mean beneficial effect of fixed mutations, under the\\u000aassumptions that the population size N is large, that the mean effect of new\\u000abeneficial mutations is smaller than the mean effect of new deleterious

Claus O. Wilke

2004-01-01

124

Differing mechanisms underlie sexual size-dimorphism in two populations of a sex-changing fish.  

PubMed

Variability in the density of groups within a patchy environment lead to differences in interaction rates, growth dynamics and social organization. In protogynous hermaphrodites there are hypothesised trade-offs among sex-specific growth, reproductive output and mortality. When differences in density lead to changes to social organization the link between growth and the timing of sex-change is predicted to change. The present study explores this prediction by comparing the social organisation and sex-specific growth of two populations of a protogynous tropical wrasse, Halichoeres miniatus, which differ in density. At a low density population a strict harem structure was found, where males maintained a tight monopoly of access and spawning rights to females. In contrast, at a high density population a loosely organised system prevailed, where females could move throughout multiple male territories. Otolith microstructure revealed the species to be annual and deposit an otolith check associated with sex-change. Growth trajectories suggested that individuals that later became males in both populations underwent a growth acceleration at sex-change. Moreover, in the high density population, individuals that later became males were those individuals that had the largest otolith size at hatching and consistently deposited larger increments throughout early larval, juvenile and female life. This study demonstrates that previous growth history and growth rate changes associated with sex change can be responsible for the sexual dimorphism typically found in sex-changing species, and that the relative importance of these may be socially constrained. PMID:20485547

McCormick, Mark I; Ryen, Christopher A; Munday, Philip L; Walker, Stefan P W

2010-01-01

125

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

126

Enriching Ploidy Level Diversity: the Role of Apomictic and Sexual Biotypes of Hieracium subgen. Pilosella (Asteraceae) that Coexist in Polyploid Populations  

Microsoft Academic Search

The capacity to generate variation in ploidy and reproductive mode was compared in facultatively apomictic versus sexual maternal\\u000a plants that coexist in two model populations. The population structure was studied in polyploid hybrid swarms comprised of\\u000a Hieracium pilosella (usually sexual, less commonly apomictic), H. bauhini (apomictic), and their hybrids (sexual, apomictic, or sterile). Relationships among established biotypes were proposed on

Anna Krahulcová; Olga Rotreklová; František Krahulec; Radka Rosenbaumová; Ivana Pla?ková

2009-01-01

127

Can sexual selection theory inform genetic management of captive populations? A review  

PubMed Central

Captive breeding for conservation purposes presents a serious practical challenge because several conflicting genetic processes (i.e., inbreeding depression, random genetic drift and genetic adaptation to captivity) need to be managed in concert to maximize captive population persistence and reintroduction success probability. Because current genetic management is often only partly successful in achieving these goals, it has been suggested that management insights may be found in sexual selection theory (in particular, female mate choice). We review the theoretical and empirical literature and consider how female mate choice might influence captive breeding in the context of current genetic guidelines for different sexual selection theories (i.e., direct benefits, good genes, compatible genes, sexy sons). We show that while mate choice shows promise as a tool in captive breeding under certain conditions, for most species, there is currently too little theoretical and empirical evidence to provide any clear guidelines that would guarantee positive fitness outcomes and avoid conflicts with other genetic goals. The application of female mate choice to captive breeding is in its infancy and requires a goal-oriented framework based on the needs of captive species management, so researchers can make honest assessments of the costs and benefits of such an approach, using simulations, model species and captive animal data. PMID:25553072

Chargé, Rémi; Teplitsky, Céline; Sorci, Gabriele; Low, Matthew

2014-01-01

128

Population genetic analysis of large sequence polymorphisms in Plasmodium falciparum blood-stage antigens  

PubMed Central

Plasmodium falciparum, the causative agent of human malaria, invades host erythrocytes using several proteins on the surface of the invasive merozoite, which have been proposed as potential vaccine candidates. Members of the multi-gene PfRh family are surface antigens that have been shown to play a central role in directing merozoites to alternative erythrocyte receptors for invasion. Recently, we identified a large structural polymorphism, a 0.58 Kb deletion, in the C-terminal region of the PfRh2b gene, present at a high frequency in parasite populations from Senegal. We hypothesize that this region is a target of humoral immunity. Here, by analyzing 371 P. falciparum isolates we show that this major allele is present at varying frequencies in different populations within Senegal, Africa, and throughout the world. For allelic dimorphisms in the asexual stage antigens, Msp-2 and EBA-175, we find minimal geographic differentiation among parasite populations from Senegal and other African localities, suggesting extensive gene flow among these populations and/or immune-mediated frequency dependent balancing selection. In contrast, we observe a higher level of inter-population divergence (as measured by Fst) for the PfRh2b deletion, similar to that observed for SNPs from the sexual stage Pfs45/48 loci, which is postulated to be under directional selection. We confirm that the region containing the PfRh2b polymorphism is a target of humoral immune responses by demonstrating antibody reactivity of endemic sera. Our analysis of inter-population divergence suggests that in contrast to the large allelic dimorphisms in EBA-175 and Msp-2, the presence or absence of the large PfRh2b deletion may not elicit frequency-dependent immune selection, but may be under positive immune selection, having important implications for the development of these proteins as vaccine candidates. PMID:19931645

Ahouidi, Ambroise D.; Bei, Amy K.; Neafsey, Daniel E.; Sarr, Ousmane; Volkman, Sarah; Milner, Dan; Cox-Singh, Janet; Ferreira, Marcelo U.; Ndir, Omar; Premji, Zul; Mboup, Souleymane; Duraisingh, Manoj T.

2009-01-01

129

Recessive Mutations from Natural Populations of NEUROSPORA CRASSA That Are Expressed in the Sexual Diplophase  

PubMed Central

Wild-collected isolates of Neurospora crassa Shear and Dodge were systematically examined for recessive mutations affecting the sexual phase of the life cycle, which is essentially diploid. Seventy-four of 99 wild-collected isolates from 26 populations in the United States, India and Pakistan carried one or more recessive mutations that reduced fertility significantly when homozygous; mutations affecting spore morphology were also detected. Limited complementation tests indicate that most of the 106 recovered mutations are unique.—The recessive diplophase (= sexual phase) mutations were uncovered by crossing each wild-collected isolate to a marked two-chromosome double-reciprocal translocation strain as "balancer." Surviving progeny receive approximately 60% of their genome from the wild parent, but receive the mating-type allele from the "balancer" parent. These progeny were backcrossed to the wild parent and were also crossed with a standard laboratory strain (fl). Reduced fertility in the backcross vs. normal fertility in the cross with the laboratory standard signals the presence of a recessive mutation in the wild-collected isolate.—Most of the mutants (95 of 106) fall into two major classes: those producing barren perithecia with no or few viable ascospores (51) and those with spore maturation defects (44). Most of the recessive barrens result either from an early block in meiosis or ascus development (25) or from a late disturbance in postmeiotic ascus behavior (18).—These recessive mutations are formally equivalent to recessive lethals in higher eukaryotes and may be important in determining the breeding structure of natural Neurospora populations. PMID:2933298

Leslie, John F.; Raju, Namboori B.

1985-01-01

130

Adaptive divergence and speciation among sexual and pseudoviviparous populations of Festuca  

PubMed Central

Pseudovivipary is an environmentally induced flowering abnormality in which vegetative shoots replace seminiferous (sexual) inflorescences. Pseudovivipary is usually retained in transplantation experiments, indicating that the trait is not solely induced by the growing environment. Pseudovivipary is the defining characteristic of Festuca vivipara, and arguably the only feature separating this species from its closest seminiferous relative, Festuca ovina. We performed phylogenetic and population genetic analysis on sympatric F. ovina and F. vivipara samples to establish whether pseudovivipary is an adaptive trait that accurately defines the separation of genetically distinct Festuca species. Chloroplast and nuclear marker-based analyses revealed that variation at a geographical level can exceed that between F. vivipara and F. ovina. We deduced that F. vivipara is a recent species that frequently arises independently within F. ovina populations and has not accumulated significant genetic differentiation from its progenitor. We inferred local gene flow between the species. We identified one amplified fragment length polymorphism marker that may be linked to a pseudovivipary-related region of the genome, and several other markers provide evidence of regional local adaptation in Festuca populations. We conclude that F. vivipara can only be appropriately recognized as a morphologically and ecologically distinct species; it lacks genetic differentiation from its relatives. This is the first report of a ‘failure in normal flowering development' that repeatedly appears to be adaptive, such that the trait responsible for species recognition constantly reappears on a local basis. PMID:20959864

Chiurugwi, T; Beaumont, M A; Wilkinson, M J; Battey, N H

2011-01-01

131

Sexual reproduction, clonal diversity and genetic differentiation in patchily distributed populations of the temperate forest herb Paris quadrifolia (Trilliaceae)  

Microsoft Academic Search

Clonal plant species have been shown to adopt different strategies to persist in heterogeneous environments by changing relative investments in sexual reproduction and clonal propagation. As a result, clonal diversity and genetic variation may be different along environmental gradients. We examined the regional and local population structure of the clonal rhizomatous forest herb Paris quadrifolia in a complex of forest

Hans Jacquemyn; Rein Brys; Olivier Honnay; Martin Hermy; Isabel Roldán-Ruiz

2006-01-01

132

Among-population variation in adipose fin size parallels the expression of other secondary sexual characteristics in  

E-print Network

secondary sexual characteristics in sockeye salmon (Oncorhynchus nerka) Peter A. H. Westley Æ Stephanie M size of mature male sockeye salmon, Oncorhynchus nerka, among five popu- lations. Populations differed. Reimchen and Temple (2004) experimentally removed adipose fins from juvenile steelhead trout, Oncorhynchus

Carlson, Stephanie

133

Association of sexual problems with social, psychological, and physical problems in men and women: a cross sectional population survey  

Microsoft Academic Search

STUDY OBJECTIVE: To investigate the association of sexual problems with social, physical, and psychological problems. DESIGN: An anonymous postal questionnaire survey. SETTING: Four general practices in England. PARTICIPANTS: 789 men and 979 women responding to a questionnaire sent to a stratified random sample of the adult general population (n = 4000). MAIN RESULTS: Strong physical, social, and psychological associations were

K. M. Dunn; P. R. Croft; G. I. Hackett

1999-01-01

134

Large-Population Face Recognition (LPFR) Using Correlation Filters  

Microsoft Academic Search

Practical face recognition applications may involve hundreds and thousands of people. Such large-population face recognition\\u000a (LPFR) can be a real challenge when the recognition system stores one template for each subject in the database and matches\\u000a each test image with a large number of templates in real-time. Such a system should also be able to handle the situation where\\u000a some

Chunyan Xie; B. V. K. Vijaya Kumar

135

The Sexual Risk Context among the FEM-PrEP Study Population in Bondo, Kenya and Pretoria, South Africa  

PubMed Central

Background Incidence rates in the FEM-PrEP and VOICE trials demonstrate that women from diverse sub-Saharan African communities continue to be at substantial HIV risk. Objective To describe and compare the sexual risk context of the study population from two FEM-PrEP trial sites–Bondo, Kenya, and Pretoria, South Africa. Methods At baseline we collected information about demographics, sexual behaviors, and partnership beliefs through quantitative questionnaires with all participants (Bondo, n?=?720; Pretoria, n?=?750). To explore the sexual risk context, we also conducted qualitative, semi-structured interviews with HIV-negative participants randomly selected at several time points (Bondo, n?=?111; Pretoria, n?=?69). Results Demographics, sexual behavior, and partnership beliefs varied significantly between the sites. Bondo participants were generally older, had fewer years of schooling, and were more likely to be employed and married compared to Pretoria participants. Bondo participants were more likely to report multiple partners and not knowing whether their partner had HIV than Pretoria participants. A significantly higher percentage of Bondo participants reported engaging in sex without a condom with their primary and other partners compared to Pretoria participants. We found a borderline association between participants who reported not using condoms in the 4 weeks prior to baseline and lower risk of HIV infection, and no association between having more than one sexual partner at baseline and HIV infection. Discussion Despite significantly different demographics, sexual behaviors, and partnership beliefs, many women in the FEM-PrEP trial were at risk of acquiring HIV as demonstrated by the sites’ high HIV incidence. Though gender dynamics differed between the populations, they appear to play a critical role in women’s sexual practices. The findings highlight different ways women from diverse contexts may be at-risk for HIV and the importance of providing HIV prevention options that are both effective and feasible given personal and social circumstances. PMID:25229403

Headley, Jennifer; Lemons, Ansley; Corneli, Amy; Agot, Kawango; Ahmed, Khatija; Wang, Meng; Odhiambo, Jacob; Skhosana, Joseph; Tharaldson, Jenae; Van Damme, Lut; MacQueen, Kathleen

2014-01-01

136

JELLYFISH BLOOMS Increasing jellyfish populations: trends in Large Marine  

E-print Network

JELLYFISH BLOOMS Increasing jellyfish populations: trends in Large Marine Ecosystems Lucas Brotz there are various indications and claims that jellyfish (i.e., scyphozoans, cubozoans, most hydrozoans, ctenophores never been pre- sented. Because this is mainly due to scarcity of quantitative time series of jellyfish

Pauly, Daniel

137

Cryptic sexual populations account for genetic diversity and ecological success in a widely distributed, asexual fungus-growing ant.  

PubMed

Sex and recombination are central processes in life generating genetic diversity. Organisms that rely on asexual propagation risk extinction due to the loss of genetic diversity and the inability to adapt to changing environmental conditions. The fungus-growing ant species Mycocepurus smithii was thought to be obligately asexual because only parthenogenetic populations have been collected from widely separated geographic localities. Nonetheless, M. smithii is ecologically successful, with the most extensive distribution and the highest population densities of any fungus-growing ant. Here we report that M. smithii actually consists of a mosaic of asexual and sexual populations that are nonrandomly distributed geographically. The sexual populations cluster along the Rio Amazonas and the Rio Negro and appear to be the source of independently evolved and widely distributed asexual lineages, or clones. Either apomixis or automixis with central fusion and low recombination rates is inferred to be the cytogenetic mechanism underlying parthenogenesis in M. smithii. Males appear to be entirely absent from asexual populations, but their existence in sexual populations is indicated by the presence of sperm in the reproductive tracts of queens. A phylogenetic analysis of the genus suggests that M. smithii is monophyletic, rendering a hybrid origin of asexuality unlikely. Instead, a mitochondrial phylogeny of sexual and asexual populations suggests multiple independent origins of asexual reproduction, and a divergence-dating analysis indicates that M. smithii evolved 0.5-1.65 million years ago. Understanding the evolutionary origin and maintenance of asexual reproduction in this species contributes to a general understanding of the adaptive significance of sex. PMID:21768368

Rabeling, Christian; Gonzales, Omar; Schultz, Ted R; Bacci, Maurício; Garcia, Marcos V B; Verhaagh, Manfred; Ishak, Heather D; Mueller, Ulrich G

2011-07-26

138

Admixture and sexual bias in the population settlement of La Réunion Island (Indian Ocean).  

PubMed

La Réunion, one of the three Mascarene islands located in the Indian Ocean, remained devoid of inhabitants until it was first colonized by the French in the middle of the 17th century. The continuous flow of foreign-born slaves and immigrant workers from Africa, India, Southeast Asia, and China to work on coffee and sugar cane plantations led to the island becoming a melting pot of people of multiple ethnic origins. To establish the impact of the different incoming ethnic groups on the present Reunionese gene pool, we have sequenced both hypervariable regions I and II of the mitochondrial DNA molecule, the 9 bp COII/tRNA(Lys) deletion, and four SNPs located in the coding region in a total of 41 samples of the general population, and a further 18 STRs and 35 SNPs on the Y chromosome in 26 of these samples. Our results show that there was a strong sexual bias (asymmetrical gene flow) in the peopling of La Réunion, where admixture events were mainly between male settlers and females from the incoming slave groups. Most of the Y-chromosome gene pool is of European/Middle Eastern ancestry (85%), whereas the mtDNA gene pool is mainly of Indian and East Asian ancestry (70%). The absence of genetic diversity within these two major components of the mtDNA gene pool suggests these populations may have witnessed strong founder effects during the colonization process. PMID:18186507

Berniell-Lee, Gemma; Plaza, Stéphanie; Bosch, Elena; Calafell, Francesc; Jourdan, Eric; Césari, Maya; Lefranc, Gérard; Comas, David

2008-05-01

139

Treatment-seeking behavior for sexually transmitted infections in a high-risk population.  

PubMed

The World Health Organization estimates that 340 million new cases of curable sexually transmitted infections (STIs) occur every year, while 33 million individuals are estimated to be living with HIV. The AIDS and STI epidemics are not independent with untreated STIs increasing HIV acquisition and transmission. Female sex workers have increased prevalence of untreated STIs and have been hypothesized to affect the health and HIV incidence of the general population. This paper aims to investigate why some female sex workers who experience symptoms of vaginal discharge or genital ulcers seek treatment while others do not. Data were collected from a cohort study conducted between 2002 and 2005 among female bar and hotel workers in Moshi, Tanzania. Study subjects were recruited from 7 out of 15 administrative wards in Moshi as part of the Moshi's Women's Health Project. Data were restricted to women self-reporting symptoms of vaginal discharge or genital ulcers (n=459) within the past year. Logistic regression was performed with SAS 9.1. Qualitative analysis was performed using in-depth interviews and focus group discussions among a convenience sample (n=42) of women already enrolled in the study. All interviews and focus group discussions were tape-recorded and transcribed, and data were analyzed thematically. Sixty-four percent of the sample sought treatment for either ailment. Multivariate analysis identified relationship to man of last sexual intercourse, ever experiencing a pregnancy, and age as significant predictors to seeking treatment. Four salient themes of threats to fertility, stigma correlated with prostitution, discomfort with the physical exam, and perceived views of clients were revealed as predictors to why women seek or intentionally ignore symptoms. Understanding the motivations and barriers for seeking treatment of STIs has far ranging public health implications that could help curtail the unnecessary associated morbidity and mortality and curtail the transmission of HIV. PMID:20635239

Rosenheck, Rachel; Ngilangwa, David; Manongi, Rachael; Kapiga, Saidi

2010-11-01

140

Laboratory mating trials indicate incipient speciation by sexual selection among populations of the cichlid fish Pseudotropheus zebra from Lake Malawi.  

PubMed Central

It has been suggested that sexual selection may have played a major role in the rapid evolution of hundreds of species of cichlid fishes in Lake Malawi. We report the results of a laboratory test of assortative mating among Lake Malawi cichlid fishes from five closely related geographical populations differing in male courtship colour. Paternity of clutches was tested using microsatellite DNA typing of offspring. Out of 1955 offspring typed, 1296 (66.3%) were sired by the male from the same population as the female, which is more than three times the rate expected if females do not differentiate among males of the different populations (20%). This result indicates that mate preferences of geographical races are strongly differentiated, consistent with the races representing incipient geographical species diverging under sexual selection exerted by female preferences for different male courtship colours. PMID:15209099

Knight, Mairi E.; Turner, George F.

2004-01-01

141

Men's Sexual Interest in Children: One-Year Incidence and Correlates in a Population-Based Sample of Finnish Male Twins.  

PubMed

In a study of 1,310 Finnish adult male twins we found that sexual interest in children aged 12 or younger was reported by 0.2% of the sample. Sexual interest in children aged 15 or younger was reported by 3.3%. Participants reporting sexual interest in children aged 15 or younger were younger, reported stronger sexual desire, and had experienced more childhood sexual and nonsexual abuse. The present study is the first to give a population-based estimate of the incidence of sexual interest in children among adult men. The 12-month incidence of sexual interest in children below the age of 16 years is roughly comparable to the one-year incidence of major depression or the lifetime prevalence of transvestitic fetishism. PMID:25747416

Santtila, Pekka; Antfolk, Jan; Räfså, Anna; Hartwig, Maria; Sariola, Heikki; Sandnabba, N Kenneth; Mokros, Andreas

2015-01-01

142

Social factors associated with readiness for sexual activity in adolescents: a population-based cohort study.  

PubMed

Various factors are associated with sexual activity in adolescence and it is important to identify those that promote healthy and adaptive romantic and sexual development. The objectives of this study were to describe rates of early sexual intercourse (before 16 years) and sexual readiness in adolescence and to assess the extent to which these were social patterned. We prospectively studied nearly 5,000 15-year-olds from the Avon Longitudinal Study of Parents and Children, a UK birth cohort. Between 2006 and 2008, female and male participants answered a computer assisted interview about romantic and sexual behaviors in the last year. Predictors of sexual intercourse and readiness for sexual intercourse were examined across a range of sociodemographic measures. Overall, 17.7 % (95 % CI 16.7 %, 18.9 %) of participants reported having had sexual intercourse in the last year, with more girls than boys reporting sexual experience (risk ratio 1.30, 95 % CI 1.15, 1.47). Of these, one-third of both male and female were classed as unready because they were unwilling, lacking in autonomy, felt regret or had not used contraception. There was strong evidence of social patterning for sexual activity with higher rates for young people from poorer homes, with lower social class, and with younger, less educated mothers. In contrast, among 860 young people who had had sexual intercourse, there was no clear evidence of associations between social factors and sexual readiness. The lack of social patterning in sexual readiness supports the provision of comprehensive education to develop life skills for adolescents across all social groups. PMID:23982565

Heron, Jon; Low, Nicola; Lewis, Glyn; Macleod, John; Ness, Andy; Waylen, Andrea

2015-04-01

143

Multi-level sexual selection: Individual and family-level selection for mating success in a historical human population  

PubMed Central

Precopulatory sexual selection is the association between fitness and traits associated with mate acquisition. While sexual selection is generally recognized to be a powerful evolutionary force, most investigations are limited to characters belonging to individuals. A broader multi-level perspective acknowledges that individual fitness can be affected by aspects of mating success that are characters of groups, such as families. Parental mating success in polygynous or polyandrous human societies may exemplify traits under group-level sexual selection. Using fitness measures that account for age-structure, I measure multi-level selection for mate number over 55 years in a human population with declining rates of polygyny. Sexual selection had three components: individual-level selection for ever-mating (whether or not an individual mated) and individual- and family-level selection for polyandry and polygyny. Family- and individual-level selection for polygyny was equally strong, three times stronger than family-level selection for polyandry and more than an order of magnitude stronger than individual-level selection for polyandry. However, individual-level selection for polyandry and polygyny was more effective at explaining relative fitness variance than family-level selection. Selection for ever-mating was the most important source of sexual selection for fitness; variation for ever-mating explained 23% of relative fitness variance. PMID:23730758

Moorad, Jacob

2013-01-01

144

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

145

Twenty years after International Conference on Population and Development: where are we with adolescent sexual and reproductive health and rights?  

PubMed

The International Conference on Population and Development in Cairo in 1994 laid out a bold, clear, and comprehensive definition of reproductive health and called for nations to meet the educational and service needs of adolescents to enable them to deal in a positive and responsible way with their sexuality. In the context of the ongoing review of the International Conference on Population and Development Programme of Action and the considerations for a post-2015 development agenda, this article summarizes the findings of the articles presented in this volume and identifies key challenges and critical answers that need to be tackled in addressing adolescent sexual and reproductive health and rights. The key recommendations are to link the provision of sexuality education and sexual and reproductive health (SRH) services; build awareness, acceptance, and support for youth-friendly SRH education and services; address gender inequality in terms of beliefs, attitudes, and norms; and target the early adolescent period (10-14 years). The many knowledge gaps, however, point to the pressing need for further research on how to best design effective adolescent SRH intervention packages and how best to deliver them. PMID:25528975

Chandra-Mouli, Venkatraman; Svanemyr, Joar; Amin, Avni; Fogstad, Helga; Say, Lale; Girard, Françoise; Temmerman, Marleen

2015-01-01

146

Poppr: an R package for genetic analysis of populations with clonal, partially clonal, and/or sexual reproduction  

PubMed Central

Many microbial, fungal, or oomcyete populations violate assumptions for population genetic analysis because these populations are clonal, admixed, partially clonal, and/or sexual. Furthermore, few tools exist that are specifically designed for analyzing data from clonal populations, making analysis difficult and haphazard. We developed the R package poppr providing unique tools for analysis of data from admixed, clonal, mixed, and/or sexual populations. Currently, poppr can be used for dominant/codominant and haploid/diploid genetic data. Data can be imported from several formats including GenAlEx formatted text files and can be analyzed on a user-defined hierarchy that includes unlimited levels of subpopulation structure and clone censoring. New functions include calculation of Bruvo’s distance for microsatellites, batch-analysis of the index of association with several indices of genotypic diversity, and graphing including dendrograms with bootstrap support and minimum spanning networks. While functions for genotypic diversity and clone censoring are specific for clonal populations, several functions found in poppr are also valuable to analysis of any populations. A manual with documentation and examples is provided. Poppr is open source and major releases are available on CRAN: http://cran.r-project.org/package=poppr. More supporting documentation and tutorials can be found under ‘resources’ at: http://grunwaldlab.cgrb.oregonstate.edu/. PMID:24688859

Tabima, Javier F.; Grünwald, Niklaus J.

2014-01-01

147

Sexual and reproductive knowledge, attitudes and behaviours in a school going population of Sri Lankan adolescents.  

PubMed

The reproductive and sexual health of adolescents is an important health concern and a focus of global attention. In Sri Lanka, a lack of understanding about adolescent reproductive and sexual health needs is a matter of national concern. A survey was undertaken to examine the sexual knowledge, attitudes and behaviours of school going adolescents in Sri Lanka. A random sample of schools was selected from one district. Data were collected by a self-completion questionnaire and analysed using SPSS. Response rate was 90%. 2020 pupils (26% boys, 74% girls) aged 16-19 years (mean?=?16.9) participated, the majority Sinhalese (97%). Most reported a good parent-child relationship (88%). A minority (34%) discussed sexual issues with parents. Health professionals were the preferred source of sexual information (32%) rather than parents (12.5%) or friends (5.6%). Less than 1% demonstrated satisfactory sexual and reproductive knowledge levels. 1.7% were sexually active (30 boys vs 5 girls), the majority with same age partners. 57% used contraception at first intercourse. There is an imperative to address the lack of sexual and reproductive knowledge. A minority of school going adolescents become sexually active. These individuals are potentially vulnerable and services need to be developed to meet their needs. PMID:25637417

Rajapaksa-Hewageegana, Neelamani; Piercy, Hilary; Salway, Sarah; Samarage, Sarath

2015-03-01

148

Morphometric analysis of pelvic sexual dimorphism in a contemporary Western Australian population.  

PubMed

Requisite to routine casework involving unidentified skeletal remains is the formulation of an accurate biological profile, including sex estimation. Choice of method(s) is invariably related to preservation and by association, available bones. It is vital that the method applied affords statistical quantification of accuracy rates and predictive confidence so that evidentiary requirements for legal submission are satisfied. Achieving the latter necessitates the application of contemporary population-specific standards. This study examines skeletal pelvic dimorphism in contemporary Western Australian individuals to quantify the accuracy of using pelvic measurements to estimate sex and to formulate a series of morphometric standards. The sample comprises pelvic multi-slice computer tomography (MSCT) scans from 200 male and 200 female adults. Following 3D rendering, the 3D coordinates of 24 landmarks are acquired using OsiriX® (v.4.1.1) with 12 inter-landmark linear measurements and two angles acquired using MorphDb. Measurements are analysed using basic descriptive statistics and discriminant functions analyses employing jackknife validation of classification results. All except two linear measurements are dimorphic with sex differences explaining up to 65 % of sample variance. Transverse pelvic outlet and subpubic angle contribute most significantly to sex discrimination with accuracy rates between 100 % (complete pelvis-10 variables) and 81.2 % (ischial length). This study represents the initial forensic research into pelvic sexual dimorphism in a Western Australian population. Given these methods, we conclude that this highly dimorphic bone can be used to classify sex with a high degree of expected accuracy. PMID:24789357

Franklin, Daniel; Cardini, Andrea; Flavel, Ambika; Marks, Murray K

2014-09-01

149

Extensive Genetic Diversity, Unique Population Structure and Evidence of Genetic Exchange in the Sexually Transmitted Parasite Trichomonas vaginalis  

PubMed Central

Background Trichomonas vaginalis is the causative agent of human trichomoniasis, the most common non-viral sexually transmitted infection world-wide. Despite its prevalence, little is known about the genetic diversity and population structure of this haploid parasite due to the lack of appropriate tools. The development of a panel of microsatellite makers and SNPs from mining the parasite's genome sequence has paved the way to a global analysis of the genetic structure of the pathogen and association with clinical phenotypes. Methodology/Principal Findings Here we utilize a panel of T. vaginalis-specific genetic markers to genotype 235 isolates from Mexico, Chile, India, Australia, Papua New Guinea, Italy, Africa and the United States, including 19 clinical isolates recently collected from 270 women attending New York City sexually transmitted disease clinics. Using population genetic analysis, we show that T. vaginalis is a genetically diverse parasite with a unique population structure consisting of two types present in equal proportions world-wide. Parasites belonging to the two types (type 1 and type 2) differ significantly in the rate at which they harbor the T. vaginalis virus, a dsRNA virus implicated in parasite pathogenesis, and in their sensitivity to the widely-used drug, metronidazole. We also uncover evidence of genetic exchange, indicating a sexual life-cycle of the parasite despite an absence of morphologically-distinct sexual stages. Conclusions/Significance Our study represents the first robust and comprehensive evaluation of global T. vaginalis genetic diversity and population structure. Our identification of a unique two-type structure, and the clinically relevant phenotypes associated with them, provides a new dimension for understanding T. vaginalis pathogenesis. In addition, our demonstration of the possibility of genetic exchange in the parasite has important implications for genetic research and control of the disease. PMID:22479659

Conrad, Melissa D.; Gorman, Andrew W.; Schillinger, Julia A.; Fiori, Pier Luigi; Arroyo, Rossana; Malla, Nancy; Dubey, Mohan Lal; Gonzalez, Jorge; Blank, Susan; Secor, William E.; Carlton, Jane M.

2012-01-01

150

Assessment of hydration status in a large population.  

PubMed

Both acute and chronic dehydration can have important implications for human behaviour and health. Young children, non-autonomous individuals and the elderly are at a greater risk of dehydration. Mild hypertonic dehydration could be related to less efficient cognitive and physical performance and has been reported to be associated with frequently occurring pathological conditions, especially nephrolithiasis. The assessment of hydration status in a large sample appears to be of interest for conducting epidemiological and large clinical studies aimed at improving preventive and curative care. Especially in large-population studies, methods that are used have to be accurate, cheap, quick and require no technical expertise. Body weight change is widely used to determine acute hydration changes, but seems to be insufficiently accurate in longitudinal studies. Bioimpedance analysis methods enable the assessment of total body water content, but their use is still under debate. Because plasma osmolality directly reflects intracellular osmolality, it constitutes a good marker to assess acute hydration changes, but not chronic hydration status because it changes constantly. Moreover, venepuncture is considered to be invasive and is not suitable for a large-sample study, especially in children. Urinary markers appear to be good alternatives for assessing hydration status in large populations. Collection of urine samples is non-invasive and cheap. High technical expertise is not required to perform urinary marker measurements and these measurements can be carried out quickly. Thus, methods based on urinary markers are very well suited for field studies. Urine colour is probably the least sensitive marker despite its high specificity. Urine osmolality and especially urine specific gravity could be easily used for determining hydration status in large-sample studies. PMID:25418739

Baron, Stephanie; Courbebaisse, Marie; Lepicard, Eve M; Friedlander, Gerard

2014-11-24

151

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

Microsoft Academic Search

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

De Kovel; De Jong

2000-01-01

152

Adjustment among mothers reporting same-gender sexual partners: a study of a representative population sample from Quebec Province (Canada).  

PubMed

We examined the well-being of mothers and non-mothers reporting exclusive opposite-gender sexual partners (OG), same-gender sexual partners (SG), or both (BI) in a representative sample of 20,773 participants (11,034 women) 15-years-old or older from the population of Quebec province in Canada. Participants completed a self-administered questionnaire and SG and BI women (n = 179) were matched to a sample of OG women (n = 179) based on age, income, geographical area, and children (having at least one 18-year-old or younger biological or adopted child at home). We assessed social milieu variables, risk factors for health disorders, mental health, and quality of mothers' relationship with children. The findings indicated a sexual orientation main effect: Mothers and non-mothers in the SG and BI group, as compared to their OG controls, were significantly less likely to live in a couple relationship, had significantly lower levels of social support, higher prevalence of early negative life events, substance abuse, suicide ideation, and higher levels of psychological distress. There were no Sexual Orientation X Parenthood status effects. The results further indicated that sexual orientation did not account for unique variance in women's psychological distress beyond that afforded by their social milieu, health risk factors, and parenthood status. No significant differences were found for the quality of mothers' relationship with children. SG-BI and OG mothers with low levels of social integration were significantly more likely to report problems with children than parents with high levels of social integration. We need to understand how marginal sexualities and their associated social stigma, as risk indicators for mothers, interact with other factors to impact family life, parenting skills, and children's adjustment. PMID:17665300

Julien, Danielle; Jouvin, Emilie; Jodoin, Emilie; L'archevêque, Alexandre; Chartrand, Elise

2008-12-01

153

Evaluation of three gears for sampling spawning populations of rainbow trout in a large Alaskan river  

USGS Publications Warehouse

Alternatives to electrofishing are needed for sampling sexually mature rainbow trout Oncorhynchus mykiss during the spawning season in large Alaskan rivers. We compared hook and line, beach seining, and actively fished gill nets as sampling tools. Beach seining and active gill netting yielded similar catch rates, length frequencies, and sex ratios of sexually mature fish. Hook-and-line sampling was less effective, with a lower catch rate and selectivity for immature fish and sexually mature females. We conclude that both beach seining and active gill netting can serve as alternatives to electrofishing for sampling sexually mature rainbow trout stocks during the spawning season in large rivers with stable spring flows and spawning areas with few snags.

Schwanke, C.J.; Hubert, W.A.

2004-01-01

154

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

Microsoft Academic Search

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

Julia Camuso; Alessandra H. Rellini

2010-01-01

155

Sexual harassment victimization and perpetration among high school students.  

PubMed

This large, population-based study is one of the few to examine prevalence rates of sexual harassment occurring during the past 12 months by victimization and perpetration among adolescents. In this large, cross-sectional survey of students attending 26 high schools, sexual harassment was defined using three questions from the Sexual Experiences Questionnaire. Among 18,090 students completing the survey, 30% disclosed sexual harassment victimization (37% of females, 21% of males) and 8.5% reported perpetration (5% of females, 12% of males). Sexual harassment perpetration was highly correlated with male sex, minority race/ethnicity, same-sex attraction, bullying, alcohol binge drinking, and intraparental partner violence. PMID:25288593

Clear, Emily R; Coker, Ann L; Cook-Craig, Patricia G; Bush, Heather M; Garcia, Lisandra S; Williams, Corrine M; Lewis, Alysha M; Fisher, Bonnie S

2014-10-01

156

New insights into the variability of reproduction modes in European populations of Rubus subgen. Rubus: how sexual are polyploid brambles?  

PubMed

Rubus subgen. Rubus includes common European species with highly complicated taxonomy, ongoing hybridisation and facultative apomixis. Out of approximately 750 species recognised in Europe, only 3 diploid sexual species are known, along with numerous apomictic brambles that are highly connected to polyploidy. One exception of a tetraploid taxon is R. ser. Glandulosi, which is known for prevalent sexuality. This taxon highly hybridises with tetraploid members of R. ser. Discolores and leads to the origin of many hybridogenous populations and individuals. In this study, we verify reproduction modes in different diploid, triploid and tetraploid species of subgen. Rubus, with focus on taxa putatively involved in such hybridisation by applying flow cytometric seed screen analysis. We found 100 % sexuality of diploid species, whereas triploid species had obligate unreduced embryo sac development. In contrast, tetraploid plants had varying degrees of sexuality. Additionally, we discovered that R. bifrons has the ability to undergo a reproduction mode switch as a reaction to environmental conditions. These results provide insight into reproductive modes of European brambles and shed light on their reticulate evolution and speciation. PMID:23114637

Šarhanová, Petra; Vašut, Radim J; Dan?ák, Martin; Bureš, Petr; Trávní?ek, Bohumil

2012-12-01

157

Bowel, Urinary, and Sexual Problems Among Long-Term Prostate Cancer Survivors: A Population-Based Study  

SciTech Connect

Purpose: To obtain insight into the long-term (5- to 10-year) effects of prostate cancer and treatment on bowel, urinary, and sexual function, we performed a population-based study. Prostate-specific function was compared with an age-matched normative population without prostate cancer. Methods and Materials: Through the population-based Eindhoven Cancer Registry, we selected all men diagnosed with prostate cancer between 1994 and 1998 in the southern Netherlands. In total, 964 patients, alive in November 2004, received questionnaire; 780 (81%) responded. Results: Urinary problems were most common after a prostatectomy; bowel problems were most common after radiotherapy. Compared with an age-matched normative population both urinary and bowel functioning and bother were significantly worse among survivors. Urinary incontinence was reported by 23-48% of survivors compared with 4% of the normative population. Bowel leakage occurred in 5-14% of patients compared with 2% of norms. Erection problems occurred in 40-74% of patients compared with 18% of norms. Conclusions: These results form an important contribution to the limited information available on prostate-specific problems in the growing group of long-term prostate cancer survivors. Bowel, urinary, and sexual problems occur more often among long-term survivors compared with a reference group and cannot be explained merely by age. Because these problems persist for many years, urologists should provide patients with adequate information before treatment. After treatment, there should be an appropriate focus on these problems.

Mols, Floortje [CoRPS-Center of Research on Psychology in Somatic Diseases, Tilburg University, Tilburg (Netherlands); Comprehensive Cancer Centre South (CCCS), Eindhoven Cancer Registry, Eindhoven (Netherlands)], E-mail: F.Mols@uvt.nl; Korfage, Ida J. [Department of Public Health, Erasmus MC-University Medical Center, Rotterdam (Netherlands); Vingerhoets, Ad J.J.M. [Clinical Psychology Section, Tilburg University, Tilburg (Netherlands); Kil, Paul J.M. [Department of Urology, Sint Elisabeth Hospital, Tilburg (Netherlands); Coebergh, Jan Willem W. [Comprehensive Cancer Centre South (CCCS), Eindhoven Cancer Registry, Eindhoven (Netherlands); Department of Public Health, Erasmus MC-University Medical Center, Rotterdam (Netherlands); Essink-Bot, Marie-Louise [Department of Public Health, Erasmus MC-University Medical Center, Rotterdam (Netherlands); Department of Social Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam (Netherlands); Poll-Franse, Lonneke V. van de [CoRPS-Center of Research on Psychology in Somatic Diseases, Tilburg University, Tilburg (Netherlands); Comprehensive Cancer Centre South (CCCS), Eindhoven Cancer Registry, Eindhoven (Netherlands)

2009-01-01

158

Age at sexual maturity, sex ratio, fecundity, and longevity of isolated headwater populations of Westslope cutthroat trout  

USGS Publications Warehouse

We sampled 19 isolated headwater populations of westslope cutthroat trout Oncorhynchus clarki lewisi in Montana to provide estimates of fecundity, longevity, sex ratio, and age at sexual maturity. Fecundity was estimated for 31 fish collected from two streams in the upper Missouri River drainage. Females smaller than 149 mm fork length (FL) were generally immature and their fecundities could not be estimated. Mean fecundities (SD) were 227 eggs (41.1) for 150-174-mm fish, 346 eggs (85.6) for 175-199-mm fish, and 459 eggs (150.8) for 200-mm and larger fish. A linear regression model (two stream samples combined) to predict fecundity (E) from fork length was developed (E = -494.9 + 4.4.FL: r2 = 0.51, P < 0.001) for westslope cutthroat trout in the upper Missouri River drainage. Regression slopes of fecundity against fish length differed significantly (P < 0.01) between these and some of the previously studied populations. Steeper slopes were associated with lacustrine-adfluvial populations. The average sex ratio was 1.3 males per female across all sampled streams. Males began to mature sexually at age 2 and all were mature by age 4. Some females (27%) were sexually mature at age 3 and most of them (93%) were mature by age 5. Length was a better predictor of sexual maturity than age. Males matured at 110-160 mm and females at 150-180 mm FL. The maximum estimated age was 8 years based on otoliths from 475 fish collected from our 19 study streams and 14 additional streams.

Downs, C.C.; White, R.G.; Shepard, B.B.

1997-01-01

159

Sexual Cannibalism: High Incidence in a Natural Population with Benefits to Females  

PubMed Central

Background Sexual cannibalism may be a form of extreme sexual conflict in which females benefit more from feeding on males than mating with them, and males avoid aggressive, cannibalistic females in order to increase net fitness. A thorough understanding of the adaptive significance of sexual cannibalism is hindered by our ignorance of its prevalence in nature. Furthermore, there are serious doubts about the food value of males, probably because most studies that attempt to document benefits of sexual cannibalism to the female have been conducted in the laboratory with non-natural alternative prey. Thus, to understand more fully the ecology and evolution of sexual cannibalism, field experiments are needed to document the prevalence of sexual cannibalism and its benefits to females. Methodology/Principal Findings We conducted field experiments with the Mediterranean tarantula (Lycosa tarantula), a burrowing wolf spider, to address these issues. At natural rates of encounter with males, approximately a third of L. tarantula females cannibalized the male. The rate of sexual cannibalism increased with male availability, and females were more likely to kill and consume an approaching male if they had previously mated with another male. We show that females benefit from feeding on a male by breeding earlier, producing 30% more offspring per egg sac, and producing progeny of higher body condition. Offspring of sexually cannibalistic females dispersed earlier and were larger later in the season than spiderlings of non-cannibalistic females. Conclusions/Significance In nature a substantial fraction of female L. tarantula kill and consume approaching males instead of mating with them. This behaviour is more likely to occur if the female has mated previously. Cannibalistic females have higher rates of reproduction, and produce higher-quality offspring, than non-cannibalistic females. Our findings further suggest that female L. tarantula are nutrient-limited in nature and that males are high-quality prey. The results of these field experiments support the hypothesis that sexual cannibalism is adaptive to females. PMID:18941517

Rabaneda-Bueno, Rubén; Rodríguez-Gironés, Miguel Á.; Aguado-de-la-Paz, Sara; Fernández-Montraveta, Carmen; De Mas, Eva; Wise, David H.; Moya-Laraño, Jordi

2008-01-01

160

Psychopathology in a Large Cohort of Sexually Abused Children Followed up to 43 Years  

ERIC Educational Resources Information Center

Objective: To determine the rate and risk of clinical and personality disorders diagnosed in childhood and adulthood in those known to have been sexually abused during childhood. Methods: Forensic medical records of 2,759 sexually abused children assessed between 1964 and 1995 were linked with a public psychiatric database between 12 and 43 years…

Cutajar, Margaret C.; Mullen, Paul E.; Ogloff, James R. P.; Thomas, Stuart D.; Wells, David L.; Spataro, Josie

2010-01-01

161

Sexual Abuse and Suicidality: Gender Differences in a Large Community Sample of Adolescents  

ERIC Educational Resources Information Center

Objective: A cross-sectional study of gender specific relationships between self-reported child sexual abuse and suicidality in a community sample of adolescents. Method: Students aged 14 years on average (N=2,485) from 27 schools in South Australia completed a questionnaire including items on sexual abuse and suicidality, and measures of…

Martin, Graham; Bergen, Helen A.; Richardson, Angela S.; Roeger, Leigh; Allison, Stephen

2004-01-01

162

Speed of evolution in large asexual populations with diminishing returns.  

PubMed

The adaptive evolution of large asexual populations is generally characterized by competition between clones carrying different beneficial mutations. Interference slows down the adaptation speed and makes the theoretical description of the dynamics more complex with respect to the successional occurrence and fixation of beneficial mutations typical of small populations. A simplified modeling framework considering multiple beneficial mutations with equal and constant fitness advantage is known to capture some of the essential features of laboratory evolution experiments. However, in these experiments the relative advantage of a beneficial mutation is generally dependent on the genetic background. In particular, the general pattern is that, as mutations in different loci accumulate, the relative advantage of new mutations decreases, a trend often referred to as "diminishing return" epistasis. Here, we propose a phenomenological model that generalizes the fixed-advantage framework to include this negative epistasis in a simple way. We evaluate analytically as well as with direct simulations the quantitative consequences of diminishing returns on the evolutionary dynamics. The speed of adaptation decreases in time and reaches a limit value corresponding to neutral evolution in the long time limit. This corresponds to an increase of the diversity in terms of "classes of mutation" in the population. Finally, we show how the model can be compared with dynamic data on fitness and number of beneficial mutations from laboratory evolution experiments. PMID:25308509

Fumagalli, Maria R; Osella, Matteo; Thomen, Philippe; Heslot, Francois; Cosentino Lagomarsino, Marco

2015-01-21

163

Sexual orientation and suicide attempt: a longitudinal study of the general Norwegian adolescent population.  

PubMed

Past and future suicide attempt rates among gay, lesbian, and bisexual (GLB) young people were compared with those of heterosexual young people. A sample of Norwegian students (N = 2.924; grades 7-12) was followed in 3 data collection waves. Risk factors included previous suicide attempt,depressed mood, eating problems, conduct problems, early sexual debut, number of sexual partners, pubertal timing, self-concept, alcohol and drug use, atypical gender roles, loneliness, peer relations, social support, parental attachment, parental monitoring, and suicidal behavior among family and friends. When homosexual attraction, homosexual identity, and same-sex sexual behavior were entered to predict suicide attempt, only same-sex sexual behavior was significantly predictive. The increased odds could not be attributed to GLB students' greater exposure to risk factors for suicide attempt. PMID:12653422

Wichstrøm, Lars; Hegna, Kristinn

2003-02-01

164

Multivariate sexual selection on male song structure in wild populations of sagebrush crickets, Cyphoderris strepitans (Orthoptera: Haglidae)  

PubMed Central

While a number of studies have measured multivariate sexual selection acting on sexual signals in wild populations, few have confirmed these findings with experimental manipulation. Sagebrush crickets are ideally suited to such investigations because mating imposes an unambiguous phenotypic marker on males arising from nuptial feeding by females. We quantified sexual selection operating on male song by recording songs of virgin and mated males captured from three wild populations. To determine the extent to which selection on male song is influenced by female preference, we conducted a companion study in which we synthesized male songs and broadcast them to females in choice trials. Multivariate selection analysis revealed a saddle-shaped fitness surface, the highest peak of which corresponded to longer train and pulse durations, and longer intertrain intervals. Longer trains and pulses likely promote greater mate attraction, but selection for longer intertrain durations suggests that energetic constraints may necessitate “time outs”. Playback trials confirmed the selection for longer train and pulse durations, and revealed significant stabilizing selection on dominant frequency, suggesting that the female auditory system is tightly tuned to the species-specific call frequency. Collectively, our results revealed a complex pattern of multivariate nonlinear selection characterized primarily by strong stabilizing and disruptive selection on male song traits. PMID:24223293

Ower, Geoffrey D; Judge, Kevin A; Steiger, Sandra; Caron, Kyle J; Smith, Rebecca A; Hunt, John; Sakaluk, Scott K

2013-01-01

165

Large variation in mitochondrial DNA of sexual and parthenogenetic Dahlica triquetrella (Lepidoptera: Psychidae) shows multiple origins of parthenogenesis  

PubMed Central

Background Obligate parthenogenesis is relatively rare in animals. Still, in some groups it is quite common and has evolved and persisted multiple times. These groups may provide important clues to help solve the ‘paradox of sex’. Several species in the Psychidae (Lepidoptera) have obligate parthenogenesis. Dahlica triquetrella is one of those species where multiple transitions to parthenogenesis are postulated based on intensive cytological and behavioural studies. This has led to the hypothesis that multiple transitions from sexuals to diploid parthenogens occurred during and after the last glacial period, followed by transitions from parthenogenetic diploids to parthenogenetic tetraploids. Our study is the first to test these hypotheses using a molecular phylogeny based on mtDNA from multiple sexual and parthenogenetic populations from a wide geographic range. Results Parthenogenetic (and sexual) D. triquetrella are not monophyletic, and considerable sequence variation is present suggesting multiple transitions to parthenogenesis. However, we could not establish ancestral sexual haplotypes from our dataset. Our data suggest that some parthenogenetic clades have evolved, indicating origins of parthenogenesis before the last glacial period. Conclusions Multiple transitions to parthenogenesis have taken place in Dahlica triquetrella, confirming previous hypotheses. The number of different parthenogenetic clades, haplotypes and their apparent evolutionary age, clearly show that parthenogenesis has been a very successful reproductive strategy in this species over a long period. PMID:23622052

2013-01-01

166

Computing Ro in a population with heterogeneity in sexual activity and proportionate mixing using a STM-solver  

NASA Astrophysics Data System (ADS)

A model to determinate the reproductive basic number, detonated Ro, for the case of population with heterogeneity in sexual activity and proportionate mixing is solved using computer algebra and SMT solvers. Specifically Maple and Z3 were used. The code for the solution of the model was written in Z3-Python, but it can also be played by Z3-SMT-Lib. Ro represents an algebraic synthesis of every epidemiological parameter. Numerical simulations were done to prove the effectiveness of the model and the code. The algebraic structure of Ro suggests the possible control measurements that should be implemented to avoid the propagation of the sexual transmitted diseases. The obtained results are important on the computational epidemiology field. As a future investigation, it is suggested to apply the STM solvers to analyze models for other kinds of epidemic diseases.

Gutierrez A., Natalia A.

2014-06-01

167

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

168

Capturing the social demographics of hidden sexual minorities: An internet study of the transgender population in the United States  

Microsoft Academic Search

As part of a larger study, we investigated the feasibility of using Internet research to capture the demographic characteristics\\u000a of a largely closeted sexual minority and to report such characteristics in the first national study of transgender persons\\u000a ever attempted in the United States. To achieve a nonclinical national sample, online convenience sampling was used. Of 1,373\\u000a surveys received, 1,229

B. R. Simon Rosser; J. Michael Oakes; Walter O. Bockting; Michael Miner

2007-01-01

169

The evolution of the female sexual response concept: treatment implications.  

PubMed

Sexual dysfunctions have been the most prevalent group of sexual disorders and include a large number of populations of both sexes.The research of sexual behavior and treatment of women with sexual distress arises many questions related to differences in sexual response of men and women. The conceptualization of this response in modern sexology has changed over time.The objective of our paper was to present the changes and evolution of the female's sexual response concept in a summarized and integrated way, to analyze the expanded and revised definitions of the female sexual response as well as implications and recommendations of new approaches to diagnostics and treatment according to the established changes.The lack of adequate empirical basis of the female sexual response model is a critical question in the literature dealing with this issue. Some articles report that linear models demonstrate more correctly and precisely the sexual response of women with normal sexual functions in relation to women with sexual dysfunction. Modification of this model later resulted in a circular model which more adequately presented the sexual response of women with sexual function disorder than of women with normal sexual function.The nonlinear model of female sexual response constructed by Basson incorporates the value of emotional intimacy, sexual stimulus and satisfaction with the relationship. Female functioning is significantly affected by multiple psychosocial factors such as satisfaction with the relationship, self-image, earlier negative sexual experience, etc. Newly revised, expanded definitions of female sexual dysfunction try to contribute to new knowledge about a highly contextual nature of woman's sexuality so as to enhance clinical treatment of dysfunctions.The definitions emphasize the evaluation of the context of women's problematic sexual experiences. PMID:23745356

Damjanovi?, Aleksandar; Duisin, Dragana; Barisi?, Jasmina

2013-01-01

170

A Population-Based Study of Cardiovascular Disease Risk in Sexual-Minority Women  

PubMed Central

Objectives. We sought to determine if sexual-minority women were at greater risk for cardiovascular disease (CVD) than their heterosexual counterparts. Methods. We aggregated data from the 2001–2008 National Health and Nutrition Examination Surveys to examine differences in CVD risk between heterosexual and sexual-minority women by using the Framingham General CVD Risk Score to calculate a ratio of vascular and chronological age. We also examined differences in the prevalence of various CVD risk factors. Results. Sexual-minority women were more likely to be current or former smokers, to report a history of drug use, to report risky drinking, and to report a family history of CVD. On average, sexual-minority women were 13.9% (95% confidence interval [CI]?=?8.5%, 19.3%) older in vascular terms than their chronological age, which was 5.7% (95% CI?=?1.5%, 9.8%) greater than that of their heterosexual counterparts. Family history of CVD and history of drug use were unrelated to increased CVD risk, and this risk was not fully explained by either risky drinking or smoking. Conclusions. Sexual-minority women are at increased risk for CVD compared with heterosexual women. PMID:23948018

Jabson, Jennifer M.; Bucholz, Kathleen K.; Bowen, Deborah J.

2013-01-01

171

drift and selection a) selection, no genetic drift b) large population, drift + selection  

E-print Network

1 drift and selection a) selection, no genetic drift b) large population, drift + selection c) small population, drift + selection nonrandom mating affects genotypic frequencies of a population continental "mainland" population to a smaller island population pt+1 = pt + m (pm - pt ) p = pt+1 - pt = m

Dever, Jennifer A.

172

Highly Recombinant VGII Cryptococcus gattii Population Develops Clonal Outbreak Clusters through both Sexual Macroevolution and Asexual Microevolution  

PubMed Central

ABSTRACT An outbreak of the fungal pathogen Cryptococcus gattii began in the Pacific Northwest (PNW) in the late 1990s. This outbreak consists of three clonal subpopulations: VGIIa/major, VGIIb/minor, and VGIIc/novel. Both VGIIa and VGIIc are unique to the PNW and exhibit increased virulence. In this study, we sequenced the genomes of isolates from these three groups, as well as global isolates, and analyzed a total of 53 isolates. We found that VGIIa/b/c populations show evidence of clonal expansion in the PNW. Whole-genome sequencing provided evidence that VGIIb originated in Australia, while VGIIa may have originated in South America, and these were likely independently introduced. Additionally, the VGIIa outbreak lineage may have arisen from a less virulent clade that contained a mutation in the MSH2 ortholog, but this appears to have reverted in the VGIIa outbreak strains, suggesting that a transient mutator phenotype may have contributed to adaptation and evolution of virulence in the PNW outbreak. PNW outbreak isolates share genomic islands, both between the clonal lineages and with global isolates, indicative of sexual recombination. This suggests that VGII C. gattii has undergone sexual reproduction, either bisexual or unisexual, in multiple locales contributing to the production of novel, virulent subtypes. We also found that the genomes of two basal VGII isolates from HIV+ patients contain an introgression tract spanning three genes. Introgression substantially contributed to intra-VGII polymorphism and likely occurred through sexual reproduction with VGI. More broadly, these findings illustrate how both microevolution and sexual reproduction play central roles in the development of infectious outbreaks from avirulent or less virulent progenitors. PMID:25073643

Croll, Daniel; Li, Wenjun; Mieczkowski, Piotr; Carter, Dee A.; Cuomo, Christina A.; Kronstad, James W.

2014-01-01

173

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

174

Smoking Initiation, Tobacco Product Use, and Secondhand Smoke Exposure Among General Population and Sexual Minority Youth, Missouri, 2011–2012  

PubMed Central

Introduction Research indicates disparities in risky health behaviors between heterosexual and sexual minority (referred to as LGBQ; also known as lesbian, gay, bisexual, queer, and questioning) youth. Limited data are available for tobacco-use–related behaviors beyond smoking status. We compared data on tobacco age of initiation, product use, and secondhand smoke exposure between general population and LGBQ youth. Methods Data for general population youth were from the statewide, representative 2011 Missouri Youth Tobacco Survey, and data for LGBQ youth were from the 2012 Out, Proud and Healthy survey (collected at Missouri Pride Festivals). Age-adjusted Cochran-Mantel-Haenszel tests were used to examine differences between general population (N = 1,547) and LGBQ (N = 410) youth, aged 14 to 18 years. Logistic regression models identified variables associated with current smoking. Results The 2 groups differed significantly on many tobacco-use–related factors. General population youth initiated smoking at a younger age, and LGBQ youth did not catch up in smoking initiation until age 15 or 16. LGBQ youth (41.0%) soon surpassed general population youth (11.2%) in initiation and proportion of current smokers. LGBQ youth were more likely to use cigars/cigarillos, be poly-tobacco users, and be exposed to secondhand smoke (SHS) in a vehicle (for never smokers). Older age (odds ratio [OR] = 1.39, 95% confidence interval [95% CI] = 1.18–1.62), female sex (OR = 1.64, 95% CI = 1.13–2.37), LGBQ identity (OR = 3.86, 95% CI = 2.50–5.94), other tobacco product use (OR = 8.67, 95% CI = 6.01–12.51), and SHS exposure in a vehicle (OR = 5.97, 95% CI = 3.83–9.31) all significantly increased the odds of being a current smoker. Conclusion This study highlights a need for the collection of data on sexual orientation on youth tobacco surveys to address health disparities among LGBQ youth. PMID:24995655

McElroy, Jane A.; Everett, Kevin D.

2014-01-01

175

Contrasting Life Histories in Neighbouring Populations of a Large Mammal  

PubMed Central

Background A fundamental life history question is how individuals should allocate resources to reproduction optimally over time (reproductive allocation). The reproductive restraint hypothesis predicts that reproductive effort (RE; the allocation of resources to current reproduction) should peak at prime-age, whilst the terminal investment hypothesis predicts that individuals should continue to invest more resources in reproduction throughout life, owing to an ever-decreasing residual reproductive value. There is evidence supporting both hypotheses in the scientific literature. Methodology/Principal Findings We used an uncommonly large, 38 year dataset on Alpine chamois (Rupicapra rupicapra) shot at various times during the rutting period to test these two hypotheses. We assumed that body mass loss in rutting males was strongly related to RE and, using a process-based approach, modelled how male relative mass loss rates varied with age. For different regions of our study area, we provide evidence consistent with different hypotheses for reproductive allocation. In sites where RE declined in older age, this appears to be strongly linked to declining body condition in old males. In this species, terminal investment may only occur in areas with lower rates of body mass senescence. Conclusions/Significance Our results show that patterns of reproductive allocation may be more plastic than previously thought. It appears that there is a continuum from downturns in RE at old age to terminal investment that can be manifest, even across adjacent populations. Our work identifies uncertainty in the relationship between reproductive restraint and a lack of competitive ability in older life (driven by body mass senescence); both could explain a decline in RE in old age and may be hard to disentangle in empirical data. We discuss a number of environmental and anthropogenic factors which could influence reproductive life histories, underlining that life history patterns should not be generalised across different populations. PMID:22125651

Mason, Tom H. E.; Chirichella, Roberta; Richards, Shane A.; Stephens, Philip A.; Willis, Stephen G.; Apollonio, Marco

2011-01-01

176

Characteristics of child sexual assault within a child advocacy center client population.  

PubMed

This descriptive study summarized data from a child advocacy center to illustrate how such information might be used to profile the scope and character of child sexual abuse (CSA) at the community level. This detailed information is not available from national or state data but is needed to understand the circumstances of the children receiving services and the type of care they may need. Variables included victim demographics, type of sexual abuse and relationship to the perpetrator, and the person to whom the victim was most likely to disclose their sexual assault. A total sample of 841 case reports was reviewed. Chi-square tests were used to determine if there were statistically significant associations between the age groupings, type of abuse, and the perpetrator according to age grouping. Those children most often seen at this child advocacy center were girls (73%); White (67%); and living with their mothers, with both parents, or with parent and stepparent (80%). The incidence of CSA increased for girls across age groups. However, boys aged 6-10 years comprised the greatest percentage of the male sample (56%) who experienced CSA. For all three age groups, over half of the perpetrators were identified as relatives. Most children (85%) experienced high-impact sexual abuse behaviors of fondling, penetration, or some combination thereof. Children most often disclosed CSA to their mothers. Understanding patterns of CSA at the local level provides guidance beyond national and state data to forensic nurses regarding child and family needs within their communities. PMID:25695208

Carlson, Faye M; Grassley, Jane; Reis, Janet; Davis, Kelley

2015-01-01

177

Extending Sexual Objectification Theory and Research to Minority Populations, Couples, and Men  

ERIC Educational Resources Information Center

This reaction highlights several strengths of this major contribution and discusses some future directions in this line of research. The authors offer research ideas in the areas of cultural and cross-cultural issues, couples and relationships, as well as direct and indirect effects of sexual objectification on men. In terms of providing…

Heimerdinger-Edwards, Sarah R.; Vogel, David L.; Hammer, Joseph H.

2011-01-01

178

The Link between Childhood Sexual Abuse and Myocardial Infarction in a Population-Based Study  

ERIC Educational Resources Information Center

Objectives: This study examined the relationship between childhood sexual abuse (CSA) and myocardial infarction in men and women, while controlling for social determinants (i.e., socioeconomic status, social support, mental health) and traditional cardiovascular risk factors (i.e., age, race, obesity, smoking, physical inactivity, diabetes…

Fuller-Thomson, Esme; Bejan, Raluca; Hunter, John T.; Grundland, Tamara; Brennenstuhl, Sarah

2012-01-01

179

Comparison of parasite communities in native and introduced populations of sexual and asexual mollies of  

E-print Network

male and Poecilia mexicana Steindachner (Atlantic molly) -like female (Avise et al., 1991; Schartl et mollies of the genus Poecilia M. TOBLER*, T. WAHLI§ AND I. SCHLUPP*{ *Universita¨t Zu¨rich, Zoologisches April 2005) The parasite communities of two molly species, the sexual Poecilia latipinna and the clonal

Schlupp, Ingo

180

Factors Associated with Treatment Compliance in a Population of Juvenile Sexual Offenders  

Microsoft Academic Search

Structural equation modeling was utilized to assess predictors of outcomes in a sample of 204 juvenile male sexual offenders participating in community-based treatment programming. Lower levels of client denial at intake predicted successful program compliance. Higher levels of denial were found in nonadjudicated youths. Although program attrition was high (50% in the first year), relatively few youths were expelled for

John A. Hunter; A. J. Figueredo

1999-01-01

181

How Large was the Founding Population of Darwin's Finches?  

Microsoft Academic Search

A key assumption of many allopatric speciation models is that evolution in peripheral or isolated populations is facilitated by drastic reductions in population size. Population bottlenecks are believed to lead to rapid changes in gene frequencies through genetic drift, to facilitate rapid emergence of novel phenotypes, and to enhance reproductive isolation via genetic revolutions. For such effects to occur, founding

Vladimir Vincek; Colm O'Huigin; Yoko Satta; Naoyuki Takahata; Peter T. Boag; Peter R. Grant; B. Rosemary Grant; Jan Klein

1997-01-01

182

How large was the founding population of Darwin's finches?  

PubMed Central

A key assumption of many allopatric speciation models is that evolution in peripheral or isolated populations is facilitated by drastic reductions in population size. Population bottlenecks are believed to lead to rapid changes in gene frequencies through genetic drift, to facilitate rapid emergence of novel phenotypes, and to enhance reproductive isolation via genetic revolutions. For such effects to occur, founding populations must be very small, and remain small for some time after founding. This assumption has, however, rarely been tested in nature. One approach is to exploit the polymorphism of the major histocompatibility complex (Mhc) to obtain information about the founding population. Here, we use the Mhc polymorphism to estimate the size of the founding population of Darwin's finches in the Galápagos Archipelago. The results indicate that the population could not have been smaller than 30 individuals.

Vincek, V.; O'Huigin, C.; Satta, Y.; Takahata, Y.; Boag, P. T.; Grant, P. R.; Grant, B. R.; Klein, J.

1997-01-01

183

Changes in Sexual Behavior and Attitudes Across Generations and Gender Among a Population-Based Probability Sample From an Urbanizing Province in Thailand.  

PubMed

Thailand has undergone rapid modernization with implications for changes in sexual norms. We investigated sexual behavior and attitudes across generations and gender among a probability sample of the general population of Nonthaburi province located near Bangkok in 2012. A tablet-based survey was performed among 2,138 men and women aged 15-59 years identified through a three-stage, stratified, probability proportional to size, clustered sampling. Descriptive statistical analysis was carried out accounting for the effects of multistage sampling. Relationship of age and gender to sexual behavior and attitudes was analyzed by bivariate analysis followed by multivariate logistic regression analysis to adjust for possible confounding. Patterns of sexual behavior and attitudes varied substantially across generations and gender. We found strong evidence for a decline in the age of sexual initiation, a shift in the type of the first sexual partner, and a greater rate of acceptance of adolescent premarital sex among younger generations. The study highlighted profound changes among young women as evidenced by a higher number of lifetime sexual partners as compared to older women. In contrast to the significant gender gap in older generations, sexual profiles of Thai young women have evolved to resemble those of young men with attitudes gradually converging to similar sexual standards. Our data suggest that higher education, being never-married, and an urban lifestyle may have been associated with these changes. Our study found that Thai sexual norms are changing dramatically. It is vital to continue monitoring such changes, considering the potential impact on the HIV/STIs epidemic and unintended pregnancies. PMID:25403321

Techasrivichien, Teeranee; Darawuttimaprakorn, Niphon; Punpuing, Sureeporn; Musumari, Patou Masika; Lukhele, Bhekumusa Wellington; El-Saaidi, Christina; Suguimoto, S Pilar; Feldman, Mitchell D; Ono-Kihara, Masako; Kihara, Masahiro

2014-11-18

184

Monitoring sexual behaviour in general populations: a synthesis of lessons of the past decade  

PubMed Central

This supplement contains selected papers from a workshop on the measurement of sexual behaviour in the era of HIV/AIDS held at the London School of Hygiene and Tropical Medicine in September 2003. The focus was on low and middle income countries, where the majority of HIV infections occur. The motive for holding such a meeting is easy to discern. As the AIDS pandemic continues to spread and as prevention programmes are scaling up, the need to monitor trends in sexual risk behaviours becomes ever more pressing. Behavioural data are an essential complement to biological evidence of changes in HIV prevalence or incidence. Biological evidence, though indispensable, is by itself insufficient for policy and programme guidance. AIDS control programmes need to be based on monitoring of not only trends in infections but also of trends in those behaviours that underlie epidemic curtailment or further spread. PMID:15572634

Cleland, J; Boerma, J; Carael, M; Weir, S

2004-01-01

185

Highly recombinant VGII Cryptococcus gattii population develops clonal outbreak clusters through both sexual macroevolution and asexual microevolution.  

PubMed

An outbreak of the fungal pathogen Cryptococcus gattii began in the Pacific Northwest (PNW) in the late 1990s. This outbreak consists of three clonal subpopulations: VGIIa/major, VGIIb/minor, and VGIIc/novel. Both VGIIa and VGIIc are unique to the PNW and exhibit increased virulence. In this study, we sequenced the genomes of isolates from these three groups, as well as global isolates, and analyzed a total of 53 isolates. We found that VGIIa/b/c populations show evidence of clonal expansion in the PNW. Whole-genome sequencing provided evidence that VGIIb originated in Australia, while VGIIa may have originated in South America, and these were likely independently introduced. Additionally, the VGIIa outbreak lineage may have arisen from a less virulent clade that contained a mutation in the MSH2 ortholog, but this appears to have reverted in the VGIIa outbreak strains, suggesting that a transient mutator phenotype may have contributed to adaptation and evolution of virulence in the PNW outbreak. PNW outbreak isolates share genomic islands, both between the clonal lineages and with global isolates, indicative of sexual recombination. This suggests that VGII C. gattii has undergone sexual reproduction, either bisexual or unisexual, in multiple locales contributing to the production of novel, virulent subtypes. We also found that the genomes of two basal VGII isolates from HIV(+) patients contain an introgression tract spanning three genes. Introgression substantially contributed to intra-VGII polymorphism and likely occurred through sexual reproduction with VGI. More broadly, these findings illustrate how both microevolution and sexual reproduction play central roles in the development of infectious outbreaks from avirulent or less virulent progenitors. Importance: Cryptococcus gattii is the causative agent responsible for ongoing infections in the Pacific Northwest of the United States and western Canada. The incidence of these infections increased dramatically in the 1990s and remains elevated. These infections are attributable to three clonal lineages of C. gattii, VGIIa, VGIIb, and VGIIc, with only VGIIa identified once previously in the Pacific Northwest prior to the start of the outbreak, albeit in a less virulent form. This study addresses the origin and emergence of this outbreak, using whole-genome sequencing and comparison of both outbreak and global isolates. We show that VGIIa arose mitotically from a less virulent clonal group, possibly via the action of a mutator phenotype, while VGIIb was likely introduced from Australia, and VGIIc appears to have emerged in the United States or in an undersampled locale via sexual reproduction. This work shows that multiple processes can contribute to the emergence of an outbreak. PMID:25073643

Billmyre, R Blake; Croll, Daniel; Li, Wenjun; Mieczkowski, Piotr; Carter, Dee A; Cuomo, Christina A; Kronstad, James W; Heitman, Joseph

2014-01-01

186

Sexually transmitted infections, bacterial vaginosis, and candidiasis in women of reproductive age in rural Northeast Brazil: a population-based study  

Microsoft Academic Search

Population-based data on sexually transmitted infections (STI), bacterial vaginosis (BV), and candidiasis reflect the epidemiological situation more accurately than studies performed in specific populations, but such data are scarce. To determine the prevalence of STI, BV, and candidiasis among women of reproductive age from a resource-poor community in Northeast Brazil, a population-based cross sectional study was undertaken. All women from

Fabíola Araújo Oliveira; Viola Pfleger; Katrin Lang; Jörg Heukelbach; Iracema Miralles; Francisco Fraga; Anastácio Queiroz Sousa; Marina Stoffler-Meilicke; Ralf Ignatius; Ligia Franco Sansigolo Kerr; Hermann Feldmeier

2007-01-01

187

Sexual Abuse and Sexual Functioning in a Chronic Pelvic Pain Sample  

ERIC Educational Resources Information Center

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

Randolph, Mary E.; Reddy, Diane M.

2006-01-01

188

Assessment of sexual risk behaviors and perception of vulnerability to sexually transmitted diseases/acquired immunodeficiency syndrome in women, 1999-2012: a population based survey in a medium-sized Brazilian city.  

PubMed

Sexual behavior is a key factor for susceptibility to sexually transmitted diseases. An evaluation of the sexual behavior of women at reproductive age was conducted in 1999. A replication of this study aims to evaluate the current situation and identify changes in sexual behavior, 13 years later. This is a population-based cross-sectional study, conducted with 1071 women in Pelotas, Brazil. Compared to the 1999 study, a 14% increase in early sexual debut and an 8% decrease in the non-use of condoms were observed in 2012. The proportion of women who reported anal sex doubled between these periods. There was no trend of increase or decrease in the prevalence of behaviors with distinct patterns being observed for each of them. Reduction of non-use of condoms may be an indicator of the effectiveness of campaigns to promote safe sex. However, the increased prevalence of early sexual debut and anal sex indicates the need for campaigns to continue and to expand their focus, especially among vulnerable groups. PMID:24780361

Mesenburg, Marilia Arndt; Muniz, Ludmila Correa; Silveira, Mariângela Freitas

2014-01-01

189

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

190

Ontogeny and sexual dimorphism in a captive population of juvenile striped skunks Mephitis mephitis  

Microsoft Academic Search

Three main hypotheses can explain the origin of the sexual size dimorphism: (1) the birth-size hypothesis, which states that\\u000a birth size of males is larger than that of females; (2) the growth-rate hypothesis, which states that males grow faster than\\u000a females; (3) the growth-length hypothesis, which states that males grow for a longer period of time than females. We examined

Aurélie Renard; Sarah A. Medill; Serge Larivière

2009-01-01

191

The Speed of Evolution in Large Asexual Populations  

NASA Astrophysics Data System (ADS)

We consider an asexual biological population of constant size N evolving in discrete time under the influence of selection and mutation. Beneficial mutations appear at rate U and their selective effects s are drawn from a distribution g( s). After introducing the required models and concepts of mathematical population genetics, we review different approaches to computing the speed of logarithmic fitness increase as a function of N, U and g( s). We present an exact solution of the infinite population size limit and provide an estimate of the population size beyond which it is valid. We then discuss approximate approaches to the finite population problem, distinguishing between the case of a single selection coefficient, g( s)= ?( s- s b ), and a continuous distribution of selection coefficients. Analytic estimates for the speed are compared to numerical simulations up to population sizes of order 10300.

Park, Su-Chan; Simon, Damien; Krug, Joachim

2010-02-01

192

Sexual orientation, social capital and daily tobacco smoking: a population-based study  

PubMed Central

Background Studies have suggested poorer health in the homosexual and bisexual groups compared to heterosexuals. Tobacco smoking, which is a health-related behavior associated with psychosocial stress, may be one explanation behind such health differences. Social capital, i.e. the generalized trust in other people and social participation/social networks which decreases the costs of social interaction, has been suggested to affect health through psychosocial pathways and through norms connected with health related behaviours, The aim of this study is to investigate the association between sexual orientation and daily tobacco smoking, taking social capital into account and analyzing the attenuation of the logit after the introduction of social participation, trust and their combination in the models. Methods In 2008 a cross-sectional public health survey was conducted in southern Sweden with a postal questionnaire with 28,198 participants aged 18–80 (55% participation rate). This study was restricted to 24,348 participants without internally missing values on all included variables. Associations between sexual orientation and tobacco smoking were analyzed with logistic regression analysis. Results Overall, 11.9% of the men and 14.8% of the women were daily tobacco smokers. Higher and almost unaltered odds ratios of daily smoking compared to heterosexuals were observed for bisexual men and women, and for homosexual men throughout the analyses. The odds ratios of daily smoking among homosexual women were not significant. Only for the “other” sexual orientation group the odds ratios of daily smoking were reduced to not significant levels among both men and women, with a corresponding 54% attenuation of the logit in the “other” group among men and 31.5% among women after the inclusion of social participation and trust. In addition, only the “other” sexual orientation group had higher odds ratios of low participation than heterosexuals. Conclusions Bisexual men and women and homosexual men, but not homosexual women, are daily smokers to a higher extent than heterosexuals. Only for the “other” sexual orientation group the odds ratios of daily smoking were reduced to not significant levels after adjustments for covariates including trust and social participation. PMID:24903892

2014-01-01

193

Quantifying the gender load: can population crosses reveal interlocus sexual conflict?  

Microsoft Academic Search

Six sister populations of Drosophila melanogaster kept under identical environmental conditions for greater than 600 generations were reciprocally crossed to investigate the incidence of population divergence in allopatry. Population crosses directly influenced fitness, mating frequency, and sperm competition patterns. Changes in both female remating rate and the outcome of male sperm competition (P1 ,P 2) in response to foreign males

Tristan A. F. Long; Robert Montgomerie; Adam K. Chippindale

2006-01-01

194

Weight Misperception and Unhealthy Weight Control Behaviors Among Sexual Minorities in the General Adolescent Population  

PubMed Central

Purpose Gay, lesbian and bisexual youth may experience significant body dissatisfaction. We examined sexual orientation differences in self-perceived weight status and prevalence of potentially dangerous weight control behaviors in a representative sample of adolescents. Methods Data were obtained from 12,984 youth between 2003–2009 over four cycles of the Massachusetts Youth Risk Behavior Survey, a statewide survey of 9th–12th grade students. Self-perceived weight status and past-month unhealthy weight control behaviors (fasting >24 hours, using diet pills, and vomiting/using laxatives) were compared among gay/lesbian, bisexual, self-identified heterosexual youth with same-sex partners, unsure youth, and exclusively heterosexual youth using logistic regression, adjusting for age and race/ethnicity. Results Compared to exclusively heterosexual males, heterosexual males with prior same-sex partners and bisexual males were more likely to self-perceive as overweight despite being of healthy weight/underweight (respectively, adjusted odds ratio [AOR], 2.61; 95% confidence interval [CI], 1.68–4.05; and AOR, 2.56; 95% CI, 1.64–4.00). Compared to exclusively heterosexual females, lesbians and bisexual females were more likely to self-perceive as being of healthy weight/underweight despite being overweight/obese (respectively, AOR, 3.17; 95% CI, 1.15–8.71; and AOR, 2.00; 95% CI, 1.20–3.33). Unhealthy weight control behaviors were significantly more prevalent among sexual minority males (32.5%; AOR, 4.38; 95% CI, 3.38–5.67) and females (34.7%; AOR, 2.27; 95% CI, 1.85–2.78) when considered together relative to exclusively heterosexual males (9.7%) and females (18.8%). Conclusions One-third of sexual minority youth engage in hazardous weight control behaviors. Future research should investigate underlying mechanisms and determine whether clinicians should routinely screen for these behaviors. PMID:24182939

Hadland, Scott E.; Austin, S. Bryn; Goodenow, Carol S.; Calzo, Jerel P.

2013-01-01

195

Using behavior-analytic implicit tests to assess sexual interests among normal and sex-offender populations  

PubMed Central

Background The development of implicit tests for measuring biases and behavioral predispositions is a recent development within psychology. While such tests are usually researched within a social-cognitive paradigm, behavioral researchers have also begun to view these tests as potential tests of conditioning histories, including in the sexual domain. Objective The objective of this paper is to illustrate the utility of a behavioral approach to implicit testing and means by which implicit tests can be built to the standards of behavioral psychologists. Design Research findings illustrating the short history of implicit testing within the experimental analysis of behavior are reviewed. Relevant parallel and overlapping research findings from the field of social cognition and on the Implicit Association Test are also outlined. Results New preliminary data obtained with both normal and sex offender populations are described in order to illustrate how behavior-analytically conceived implicit tests may have potential as investigative tools for assessing histories of sexual arousal conditioning and derived stimulus associations. Conclusion It is concluded that popular implicit tests are likely sensitive to conditioned and derived stimulus associations in the history of the test-taker rather than ‘unconscious cognitions’, per se. PMID:24693346

Roche, Bryan; O’Reilly, Anthony; Gavin, Amanda; Ruiz, Maria R.; Arancibia, Gabriela

2012-01-01

196

Sexual Reproduction Plays a Major Role in the Genetic Structure of Populations of the Fungus Mycosphaerella Graminicola  

PubMed Central

The relative contributions of sexual and asexual reproduction to the genetic structure of populations can be difficult to determine for fungi that use a mixture of both types of propagation. Nuclear RFLPs and DNA fingerprints were used to make indirect and direct measures of departures from random mating in a population of the plant pathogenic fungus Mycosphaerella graminicola during the course of an epidemic cycle. DNA fingerprints resolved 617 different genotypes among 673 isolates sampled from a single field over a 3-month period. Only 7% of the isolates represented asexual clones that were found more than once in the sample. The most common clone was found four times. Genotypic diversity averaged 85% of its maximum possible value during the course of the epidemic. Analyses of multilocus structure showed that allelic distributions among RFLP loci were independent. Pairwise comparisons between individual RFLP loci showed that the majority of alleles at these loci were in gametic equilibrium. Though this fungus has the capacity for a significant level of asexual reproduction, each analysis suggested that M. graminicola populations maintain a genetic structure more consistent with random-mating over the course of an epidemic cycle. PMID:8846892

Chen, R. S.; McDonald, B. A.

1996-01-01

197

Population and habitat assessment: Monitoring bird populations over large areas: Introduction  

USGS Publications Warehouse

Monitoring provides essential information about status and change in bird populations. For Neotropical Migrant Birds (NTMBs), the North American Breeding Bird Survey (BBS) has been particularly influential in documenting regional population change and often is cited as justification for management actions. However, as with most bird surveys, the design of the BBS, and the geographic scale of the information, often limits its use either in evaluating the response of bird populations to management, or in identifying causes of population change.

Sauer, J.R.; Cooper, R.J.

2000-01-01

198

Population diversity of Puccinia graminis is sustained through sexual cycle on alternate hosts  

Technology Transfer Automated Retrieval System (TEKTRAN)

A high degree of virulence diversity has been maintained in the population of Puccinia graminis f. sp. tritici (Pgt) in northwestern United States. Although Berberis vulgaris is present in the region and Pgt has been isolated from aecial infections on B. vulgaris, the population is too diverse to be...

199

How large the population is (size)? What kind of population a country has  

E-print Network

Why do we care about sex ratio? Population pyramid A graphic representation of the distribution Intermediate Old Please identify what kind of communities these pyramids are for Impact of Population Processes boom in the U.S.) #12;5 What can you tell from this pyramid? Which population is this pyramid for? Age

Huang, Youqin

200

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

E-print Network

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

Goldschmidt, Christina

201

Smoking and intention to quit among a large sample of black sexual and gender minorities.  

PubMed

The purpose of this study is to more completely quantify smoking and intention to quit from a sample of sexual and gender minority (SGM) Black individuals (N = 639) through analysis of data collected at Pride festivals and online. Frequencies described demographic characteristics; chi-square analyses were used to compare tobacco-related variables. Black SGM smokers were more likely to be trying to quit smoking than White SGM smokers. However, Black SGM individuals were less likely than White SGM individuals to become former smokers. The results of this study indicate that smoking behaviors may be heavily influenced by race after accounting for SGM status. PMID:25470333

Jordan, Jenna N; Everett, Kevin D; Ge, Bin; McElroy, Jane A

2015-05-01

202

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 ...

203

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

Microsoft Academic Search

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

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

2011-01-01

204

Geographical variation in frond size, rootstock density, and sexual reproduction in Matteuccia struthiopteris populations in Norway  

Microsoft Academic Search

The main aim of this study was to quantify differences in the structure of dense Matteuccia struthiopteris (L) Todaro among geographically separated populations in Norway, and to relate these differences to variation in environmental\\u000a variables. A stratified random sampling procedure was applied to select 4 m2 quadrats restricted to populations dominated (>75% cover) by the fern. This dimorphic fern can produce

Arvid Odland

2007-01-01

205

Population structure and the evolution of sexual size dimorphism and sex ratios in an insular population of Florida box turtles (Terrapene carolina bauri)  

USGS Publications Warehouse

Hypotheses in the chelonian literature suggest that in species with sexual size dimorphism, the smaller sex will mature at a smaller size and a younger age than the larger sex, sex ratios should be biased in favor of the earlier maturing sex, and deviations from a 1:1 sex ratio result from maturation of the smaller sex at a younger age. I tested these hypotheses using data collected from 1991 to 1995 on an insular (Egmont Key) population of Florida box turtles, Terrapene carolina bauri. Contrary to predictions, the earlier maturing sex (males) grew to larger sizes than the late maturing sex. Males were significantly larger than females in mean carapace length but not mean body mass. Sex ratios were not balanced, favoring the earlier maturing sex (1.6 males:1 female), but the sex-ratio imbalance did not result from faster maturation of the smaller sex. The imbalance in the sex ratio in Egmont Key's box turtles is not the result of sampling biases; it may result from nest placement. Size-class structure and sex ratios can provide valuable insights into the status and trends of populations of long-lived turtles.

Dodd, C.K., Jr.

1997-01-01

206

Abortion research: attitudes, sexual behavior, and problems in a community college population.  

PubMed

150 (80 females and 70 males) community college students were surveyed regarding their attitudes toward abortion, their sexual behavior, and their problems. The profile of the students was Caucasian (95%), young (18-24 years = 87%), single (87%), middle and lower middle class, and Catholic (70%). 82% supported abortion choice, 86% had engaged in premarital sex, 70% used contraception, and 26% had premarital pregnancies. The hard reasons for abortion (rape, the woman's life, is endangered, and the fetus is defective) received high support. The soft reasons (the family cannot afford more children or the woman does not want to marry the man) received lower support. The students were divided into 3 groups of 50 students based on the number of abortion reasons they supported out of 43 reasons. The low-group that accepted 0-10 reasons was called anti-abortion. 50% of them still believed a woman has a right to an abortion vs. 97% of the pro-abortion students. The students reported many problems in their families: alcoholic home (39%), loss of a parent through death, divorce, or separation (33%), victims of severe corporal punishment (31%), one or more family members physically abused (20%), and deprived of parental affection while growing up (20%). When the anti-abortion females (N=30) were compared with the pro-abortion females (N=50), they reported significantly (p.01) more hospitalization, a greater number of physical handicaps, and more shyness (p.1). When the anti-abortion males (N=20) were compared with the pro-abortion males (N=50), they reported significantly more obesity and agoraphobia (p.05) and more convictions for a crime (p.1). Comparison of women who had abortion (N=13) with the women who had their baby (N=8) indicated that the latter reported significantly (p.01) more battering by their boyfriend or husband, significantly (p.05) more battering in their family of origin and childhood sexual abuse, and a greater tendency (p.1) to have been raped. PMID:12345019

Bryan, J W; Freed, F W

1993-02-01

207

Large Populations Are Not Always The Best Choice In Genetic Programming  

E-print Network

Large Populations Are Not Always The Best Choice In Genetic Programming Matthias Fuchs Automated@arp.anu.edu.au, URL: http://arp.anu.edu.au:80/~fuchs Abstract In genetic programming a general consensus is that the population should be as large as practically possible or sensible. In this pa­ per we examine a batch

Fernandez, Thomas

208

Do pre- and post-copulatory sexually selected traits covary in large herbivores?  

PubMed Central

Background In most species, males compete to gain both matings (via pre-copulatory competition) and fertilizations (via post-copulatory competition) to maximize their reproductive success. However, the quantity of resources devoted to sexual traits is finite, and so males are predicted to balance their investment between pre- and post-copulatory expenditure depending on the expected pay-offs that should vary according to mating tactics. In Artiodactyla species, males can invest in weapons such as horns or antlers to increase their mating gains or in testes mass/sperm dimensions to increase their fertilization efficiency. Moreover, it has been suggested that in these species, males with territory defence mating tactic might preferentially increase their investment in post-copulatory traits to increase their fertilization efficiency whereas males with female defence mating tactic might increase their investment in pre-copulatory sexually selected traits to prevent other males from copulating with females. In this study, we thus test the prediction that male’s weapon length (pre-copulatory trait) covaries negatively with relative testes size and/or sperm dimensions (post-copulatory traits) across Artiodactyla using a phylogenetically controlled framework. Results Surprisingly no association between weapon length and testes mass is found but a negative association between weapon length and sperm length is evidenced. In addition, neither pre- nor post-copulatory traits were found to be affected by male mating tactics. Conclusions We propose several hypotheses that could explain why male ungulates may not balance their reproductive investment between pre- and post-copulatory traits. PMID:24716470

2014-01-01

209

Distinct Human Stem Cell Populations in Small and Large Intestine  

PubMed Central

The intestine is composed of an epithelial layer containing rapidly proliferating cells that mature into two regions, the small and the large intestine. Although previous studies have identified stem cells as the cell-of-origin for intestinal epithelial cells, no studies have directly compared stem cells derived from these anatomically distinct regions. Here, we examine intrinsic differences between primary epithelial cells isolated from human fetal small and large intestine, after in vitro expansion, using the Wnt agonist R-spondin 2. We utilized flow cytometry, fluorescence-activated cell sorting, gene expression analysis and a three-dimensional in vitro differentiation assay to characterize their stem cell properties. We identified stem cell markers that separate subpopulations of colony-forming cells in the small and large intestine and revealed important differences in differentiation, proliferation and disease pathways using gene expression analysis. Single cells from small and large intestine cultures formed organoids that reflect the distinct cellular hierarchy found in vivo and respond differently to identical exogenous cues. Our characterization identified numerous differences between small and large intestine epithelial stem cells suggesting possible connections to intestinal disease. PMID:25751518

Cramer, Julie M.; Thompson, Timothy; Geskin, Albert; LaFramboise, William; Lagasse, Eric

2015-01-01

210

Sexually transmitted diseases and enteric infections in the male homosexual population.  

PubMed

There are certain special considerations in the management of sexually transmitted diseases (STDs) in homosexual men, with the impact of human immunodeficiency virus (HIV) infection on the presentation, diagnosis, and management of certain STDs just becoming apparent recently. Rectal and pharyngeal gonorrhea are usually asymptomatic and also more difficult to treat. The serological diagnosis of syphillis may be unreliable in acquired immunodeficiency syndrome (AIDS) patients, and HIV-seropositive homosexual men may be at risk of accelerated progression to neurosyphilis, despite treatment with benzathine penicillin. Chlamydia trachomatis is infrequently detected in patients with proctitis so therapy should be directed only at culture-positive cases. Herpes simplex is usually severe and persistent in immunosuppressed patients and may be further complicated by the development of acyclovir-resistance. Concurrent HIV infection may be associated with increased infectivity of homosexual chronic hepatitis B carriers, but milder hepatic injury and reduced efficacy of hepatitis B vaccines and immodulatory or antiviral agents. Although there is some concern regarding the possibility of increased risk of anal cancer in homosexual men, conservative management of human papilloma-virus-associated conditions is advised. The carriage of Entamoeba histolytica in this group is rarely associated with any deleterious effects and treatment should be directed only at symptomatic patients in whom other enteric pathogens have been excluded. PMID:2202414

Law, C

1990-06-01

211

Religious Climate and Health Risk Behaviors in Sexual Minority Youths: A Population-Based Study  

PubMed Central

Objectives. We examined whether the health risk behaviors of lesbian, gay, and bisexual (LGB) youths are determined in part by the religious composition of the communities in which they live. Methods. Data were collected from 31?852 high school students, including 1413 LGB students, who participated in the Oregon Healthy Teens survey in 2006 through 2008. Supportive religious climate was operationalized according to the proportion of individuals (of the total number of religious adherents) who adhere to a religion supporting homosexuality. Comprehensive data on religious climate were derived from 85 denominational groups in 34 Oregon counties. Results. Among LGB youths, living in a county with a religious climate that was supportive of homosexuality was associated with significantly fewer alcohol abuse symptoms (odds ratio [OR]?=?0.58; 95% confidence interval [CI]?=?0.40, 0.85) and fewer sexual partners (OR?=?0.77; 95% CI?=?0.60, 0.99). The effect of religious climate on health behaviors was stronger among LGB than heterosexual youths. Results remained robust after adjustment for multiple confounding factors. Conclusions. The religious climate surrounding LGB youths may serve as a determinant of their health risk behaviors. PMID:22397347

Pachankis, John E.; Wolff, Joshua

2012-01-01

212

Documentation of Sexual Partner Gender Is Low in Electronic Health Records: Observations, Predictors, and Recommendations to Improve Population Health Management in Primary Care.  

PubMed

Abstract The 2011 Institute of Medicine report on LGBT health recommended that sexual orientation and gender identity (SO/GI) be documented in electronic health records (EHRs). Most EHRs cannot document all aspects of SO/GI, but some can record gender of sexual partners. This study sought to determine the proportion of patients who have the gender of sexual partners recorded in the EHR and to identify factors associated with documentation. A retrospective analysis was done of EHR data for 40 family medicine (FM) and general internal medicine (IM) practices, comprising 170,570 adult patients seen in 2012. The primary outcome was EHR documentation of sexual partner gender. Multivariate logistic regression assessed the impact of patient, provider, and practice factors on documentation. In all, 76,767 patients (45%) had the gender of sexual partners recorded, 4.3% of whom had same-gender partners (3.5% of females, 5.6% of males). Likelihood of documentation was independently higher for women; blacks; those with a preventive visit; those with a physician assistant, nurse practitioner, or resident primary care provider (vs. attending); those at urban practices; those at smaller practices; and those at a residency FM practice. Older age and Medicare insurance were associated with lower documentation. Sexual partner gender documentation is important to identify patients for targeted prevention and support, and holds great potential for population health management, yet documentation in the EHR currently is low. Primary care practices should routinely record the gender of sexual partners, and additional work is needed to identify best practices for collecting and using SO/GI data in this setting. PMID:25290634

Nguyen, Giang T; Yehia, Baligh R

2014-10-01

213

Collective response of human populations to large-scale emergencies.  

PubMed

Despite recent advances in uncovering the quantitative features of stationary human activity patterns, many applications, from pandemic prediction to emergency response, require an understanding of how these patterns change when the population encounters unfamiliar conditions. To explore societal response to external perturbations we identified real-time changes in communication and mobility patterns in the vicinity of eight emergencies, such as bomb attacks and earthquakes, comparing these with eight non-emergencies, like concerts and sporting events. We find that communication spikes accompanying emergencies are both spatially and temporally localized, but information about emergencies spreads globally, resulting in communication avalanches that engage in a significant manner the social network of eyewitnesses. These results offer a quantitative view of behavioral changes in human activity under extreme conditions, with potential long-term impact on emergency detection and response. PMID:21479206

Bagrow, James P; Wang, Dashun; Barabási, Albert-László

2011-01-01

214

Collective Response of Human Populations to Large-Scale Emergencies  

PubMed Central

Despite recent advances in uncovering the quantitative features of stationary human activity patterns, many applications, from pandemic prediction to emergency response, require an understanding of how these patterns change when the population encounters unfamiliar conditions. To explore societal response to external perturbations we identified real-time changes in communication and mobility patterns in the vicinity of eight emergencies, such as bomb attacks and earthquakes, comparing these with eight non-emergencies, like concerts and sporting events. We find that communication spikes accompanying emergencies are both spatially and temporally localized, but information about emergencies spreads globally, resulting in communication avalanches that engage in a significant manner the social network of eyewitnesses. These results offer a quantitative view of behavioral changes in human activity under extreme conditions, with potential long-term impact on emergency detection and response. PMID:21479206

Barabási, Albert-László

2011-01-01

215

Detecting differential protein expression in large-scale population proteomics  

SciTech Connect

Mass spectrometry-based high-throughput quantitative proteomics shows great potential in clinical biomarker studies, identifying and quantifying thousands of proteins in biological samples. However, methods are needed to appropriately handle issues/challenges unique to mass spectrometry data in order to detect as many biomarker proteins as possible. One issue is that different mass spectrometry experiments generate quite different total numbers of quantified peptides, which can result in more missing peptide abundances in an experiment with a smaller total number of quantified peptides. Another issue is that the quantification of peptides is sometimes absent, especially for less abundant peptides and such missing values contain the information about the peptide abundance. Here, we propose a Significance Analysis for Large-scale Proteomics Studies (SALPS) that handles missing peptide intensity values caused by the two mechanisms mentioned above. Our model has a robust performance in both simulated data and proteomics data from a large clinical study. Because varying patients’ sample qualities and deviating instrument performances are not avoidable for clinical studies performed over the course of several years, we believe that our approach will be useful to analyze large-scale clinical proteomics data.

Ryu, Soyoung; Qian, Weijun; Camp, David G.; Smith, Richard D.; Tompkins, Ronald G.; Davis, Ronald W.; Xiao, Wenzhong

2014-06-17

216

Higher reproductive success of small males and greater recruitment of large females may explain strong reversed sexual dimorphism (RSD) in the northern goshawk.  

PubMed

Reversed sexual dimorphism (RSD), which occurs when the female of a species is larger than the male, is the rule for most birds of prey but the exception among other bird and mammal species. The selective pressures that favour RSD are an intriguing issue in animal ecology. Despite the large number of hypotheses proposed to explain the evolution of RSD, there is still no consensus about the mechanisms involved and whether they act on one or both sexes, mainly because few intrapopulation studies have been undertaken and few raptor species have been investigated. Using the strongly size-dimorphic northern goshawk (Accipiter gentilis L.) as a model, we studied a population with one of the highest densities of breeding pairs reported in the literature in order to understand selective pressures that may favour RSD. We evaluated life-history processes, including recruitment of adult breeders and reproductive success, and we explored the mechanisms thought to act on each sex, including hunting efficiency, diet, body condition and mate choice. We found that smaller males produced more fledglings than larger ones, but there was no relationship between size and reproductive success for females. The mean body size of female breeders was larger than that of female fledglings, but male fledglings and breeders did not differ in size. Male body size was related to the type but not to the amount of prey captured during the nestling stage. We conclude that RSD may be favoured in this goshawk population because small males tend to enjoy higher reproductive success and large females greater recruitment. Our results do not support the hypotheses that evolutionary reduction in male size is driven by hunting efficiency, at least during the nestling stage, or the hypotheses that it is driven by greater recruitment. Our findings also suggest that increase in female size is driven by recruitment, rather than by reproductive success as previously postulated. PMID:25424156

Pérez-Camacho, L; García-Salgado, G; Rebollo, S; Martínez-Hesterkamp, S; Fernández-Pereira, J M

2015-02-01

217

Lesbian, Gay, Bisexual, and Transgender Hate Crimes and Suicidality Among a Population-Based Sample of Sexual-Minority Adolescents in Boston  

PubMed Central

Objectives. We examined whether past-year suicidality among sexual-minority adolescents was more common in neighborhoods with a higher prevalence of hate crimes targeting lesbian, gay, bisexual, and transgender (LGBT) individuals. Methods. Participants’ data came from a racially/ethnically diverse population-based sample of 9th- through 12th-grade public school students in Boston, Massachusetts (n?=?1292). Of these, 108 (8.36%) reported a minority sexual orientation. We obtained data on LGBT hate crimes involving assaults or assaults with battery between 2005 and 2008 from the Boston Police Department and linked the data to the adolescent’s residential address. Results. Sexual-minority youths residing in neighborhoods with higher rates of LGBT assault hate crimes were significantly more likely to report suicidal ideation (P?=?.013) and suicide attempts (P?=?.006), than were those residing in neighborhoods with lower LGBT assault hate crime rates. We observed no relationships between overall neighborhood-level violent and property crimes and suicidality among sexual-minority adolescents (P?>?.05), providing evidence for specificity of the results to LGBT assault hate crimes. Conclusions. Neighborhood context (i.e., LGBT hate crimes) may contribute to sexual-orientation disparities in adolescent suicidality, highlighting potential targets for community-level suicide-prevention programs. PMID:24328619

Hatzenbuehler, Mark L.

2014-01-01

218

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

219

Frequency and density-dependent sexual selection in natural populations of Galician Littorina saxatilis Olivi  

Microsoft Academic Search

Galician exposed shore populations of the direct developing periwinkle Littorina saxatilis are strikingly polymorphic, with an ornamented and banded upper shore form and a smooth and unbanded lower shore form. Intermediates\\u000a between the two pure forms occur in a narrow mid shore zone together with the parental forms. We have previously shown that\\u000a the two pure forms share the same

Emilio Rolan-Alvarezl; Kerstin Johannesson; Anette Ekendahl

1995-01-01

220

Effect of elevation on sexual reproduction in alpine populations of Saxifraga oppositifolia (Saxifragaceae)  

Microsoft Academic Search

Self-compatibility in high arctic and alpine areas is regarded as an adaptation to low pollinator abundance. However, high\\u000a genetic variability as a consequence of outcrossing is, with regard to population persistence, favorable in highly stochastic\\u000a environments such as tundra habitats. To evaluate these contradictory scenarios, I performed in situ pollination experiments\\u000a to examine the breeding system of the predominant outcrosser

Felix Gugerli

1998-01-01

221

Human Papillomavirus Infection in a Male Population Attending a Sexually Transmitted Infection Service  

PubMed Central

Objective Human Papillomavirus (HPV) infection in men may produce cancer and other major disorders. Men play an important role in the transmission of the virus and act as a reservoir. The aim of this study was to determine the HPV-genotypes and their prevalence in a group of men attending a Sexually Transmitted Infection service. Patients and Samples Between July 2002 and June 2011, 1392 balanopreputial, 435 urethral, 123 anal, and 67 condyloma lesions from 1551 men with a mean age of 35.8±11.3 years old (range: 17–87) were collected for HPV-DNA testing. Methods A fragment of the L1-gene and a fragment of the E6/E7-genes were amplified by PCR. Positive samples were typed by hybridization. Results The HPV genome was detected in 36.9% (486/1318) balanopreputial and in 24.9% (101/405) urethral (p<0.0001) swabs from 38.1% (538) of 1469 men. Co-infections were present in 5.4% (80/1469) of cases. HPV was found in 43.9% (373/850) of men younger than 35 vs. 31.7% (187/589) of men aged >35. HPV was found in 59.4% (104) of 165 men with lesions (macroscopic or positive peniscopy), and in 22.8% (61/267) without clinical alterations. HPV was also detected in 71.4% (40/56) men with condylomata and in 58.7% (64/109) of men with positive peniscopy. Conclusions HPV prevalence in men was high and decreased with age. HPV was found more frequently in balanopreputial than in urethral swabs. There was a low rate of co-infections. Low-risk HPV vaccine genotypes were the most recurrent especially in younger. Although HPV has been associated with clinical alterations, it was also found in men without any clinical presentation. Inclusion of men in the national HPV vaccination program may reduce their burden of HPV-related disease and reduce transmission of the virus to non-vaccinated women. PMID:23372715

Álvarez-Argüelles, Marta Elena; Melón, Santiago; Junquera, Maria Luisa; Boga, Jose Antonio; Villa, Laura; Pérez-Castro, Sonia; de Oña, María

2013-01-01

222

Sexual Health  

MedlinePLUS

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

223

How populations differentiate despite gene flow: sexual and natural selection drive phenotypic divergence within a land fish, the Pacific leaping blenny  

PubMed Central

Background Divergence between populations in reproductively important features is often vital for speciation. Many studies attempt to identify the cause of population differentiation in phenotype through the study of a specific selection pressure. Holistic studies that consider the interaction of several contrasting forms of selection are more rare. Most studies also fail to consider the history of connectivity among populations and the potential for genetic drift or gene flow to facilitate or limit phenotypic divergence. We examined the interacting effects of natural selection, sexual selection and the history of connectivity on phenotypic differentiation among five populations of the Pacific leaping blenny (Alticus arnoldorum), a land fish endemic to the island of Guam. Results We found key differences among populations in two male ornaments—the size of a prominent head crest and conspicuousness of a coloured dorsal fin—that reflected a trade-off between the intensity of sexual selection (male biased sex ratios) and natural selection (exposure to predators). This differentiation in ornamentation has occurred despite evidence suggesting extensive gene flow among populations, which implies that the change in ornament expression has been recent (and potentially plastic). Conclusions Our study provides an early snapshot of divergence in reproductively important features that, regardless of whether it reflects genetic or plastic changes in phenotype, could ultimately form a reproductive barrier among populations. PMID:24884492

2014-01-01

224

Hydrodynamic stretching of single cells for large population mechanical phenotyping  

PubMed Central

Cell state is often assayed through measurement of biochemical and biophysical markers. Although biochemical markers have been widely used, intrinsic biophysical markers, such as the ability to mechanically deform under a load, are advantageous in that they do not require costly labeling or sample preparation. However, current techniques that assay cell mechanical properties have had limited adoption in clinical and cell biology research applications. Here, we demonstrate an automated microfluidic technology capable of probing single-cell deformability at approximately 2,000 cells/s. The method uses inertial focusing to uniformly deliver cells to a stretching extensional flow where cells are deformed at high strain rates, imaged with a high-speed camera, and computationally analyzed to extract quantitative parameters. This approach allows us to analyze cells at throughputs orders of magnitude faster than previously reported biophysical flow cytometers and single-cell mechanics tools, while creating easily observable larger strains and limiting user time commitment and bias through automation. Using this approach we rapidly assay the deformability of native populations of leukocytes and malignant cells in pleural effusions and accurately predict disease state in patients with cancer and immune activation with a sensitivity of 91% and a specificity of 86%. As a tool for biological research, we show the deformability we measure is an early biomarker for pluripotent stem cell differentiation and is likely linked to nuclear structural changes. Microfluidic deformability cytometry brings the statistical accuracy of traditional flow cytometric techniques to label-free biophysical biomarkers, enabling applications in clinical diagnostics, stem cell characterization, and single-cell biophysics. PMID:22547795

Gossett, Daniel R.; Tse, Henry T. K.; Lee, Serena A.; Ying, Yong; Lindgren, Anne G.; Yang, Otto O.; Rao, Jianyu; Clark, Amander T.; Di Carlo, Dino

2012-01-01

225

Determining asymptotically large population sizes in insect swarms.  

PubMed

Social animals commonly form aggregates that exhibit emergent collective behaviour, with group dynamics that are distinct from the behaviour of individuals. Simple models can qualitatively reproduce such behaviour, but only with large numbers of individuals. But how rapidly do the collective properties of animal aggregations in nature emerge with group size? Here, we study swarms of Chironomus riparius midges and measure how their statistical properties change as a function of the number of participating individuals. Once the swarms contain order 10 individuals, we find that all statistics saturate and the swarms enter an asymptotic regime. The influence of environmental cues on the swarm morphology decays on a similar scale. Our results provide a strong constraint on how rapidly swarm models must produce collective states. But our findings support the feasibility of using swarms as a design template for multi-agent systems, because self-organized states are possible even with few agents. PMID:25121646

Puckett, James G; Ouellette, Nicholas T

2014-10-01

226

Dynamics of airborne fungal populations in a large office building  

NASA Technical Reports Server (NTRS)

The increasing concern with bioaerosols in large office buildings prompted this prospective study of airborne fungal concentrations in a newly constructed building on the Gulf coast. We collected volumetric culture plate air samples on 14 occasions over the 18-month period immediately following building occupancy. On each sampling occasion, we collected duplicate samples from three sites on three floors of this six-story building, and an outdoor sample. Fungal concentrations indoors were consistently below those outdoors, and no sample clearly indicated fungal contamination in the building, although visible growth appeared in the ventilation system during the course of the study. We conclude that modern mechanically ventilated buildings prevent the intrusion of most of the outdoor fungal aerosol, and that even relatively extensive air sampling protocols may not sufficiently document the microbial status of buildings.

Burge, H. A.; Pierson, D. L.; Groves, T. O.; Strawn, K. F.; Mishra, S. K.

2000-01-01

227

Sexually transmitted organisms in sexually abused children  

PubMed Central

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

Robinson, A; Watkeys, J; Ridgway, G

1998-01-01

228

Is female preference for large sexual ornaments due to a bias to escape predation risk?  

PubMed Central

Background A female preference for intense sexual visual signals is widespread in animals. Although the preferences for a signal per se and for the intensity of the signal were often regarded to have the identical origin, no study has demonstrated if this is true. It was suggested that the female fiddler crabs prefer males with courtship structures because of direct benefit to escape predation. Here we tested if female preference for both components (i.e. presence and size) of the courtship structure in Uca lactea is from the sensory bias to escape predation. If both components have the identical origin, females should show the same response to different-sized courtship structures regardless of predation risk. Results First, we observed responses of mate-searching female U. lactea to courting males with full-sized, half-sized and no semidomes which were experimentally manipulated. Females had a directional preference for males with bigger semidomes within normal variation. Thereafter, we tested the effect of predation risk on the female bias in the non-courtship context. When threatened by an avian mock predator, females preferentially approached burrows with full-sized semidomes regardless of reproductive cycles (i.e. reproductive periods and non-reproductive periods). When the predator cue was absent, however, females preferred burrows with semidomes without discriminating structure size during reproductive periods but did not show any bias during non-reproductive periods. Conclusions Results indicate that selection for the size of courtship structures in U. lactea may have an origin in the function to reduce predation risk, but that the preference for males with structures may have evolved by female choice, independent of predation pressure. PMID:22413838

2012-01-01

229

Sexuality and breast cancer: prime time for young patients  

PubMed Central

Sexuality and sexual functioning is a cardinal domain of health-related quality of life in breast cancer patients, namely in the younger population. Young women below 40 years of age go through a time in their lives where sexual self-identity has recently matured, their professional obligations are demanding and they bear interpersonal and childbearing expectations, all of which can suffer a devastating turnaround with cancer diagnosis and its physical and psychological aftermath. Although these women’s sexuality and directed interventions have remained largely unaddressed so far, concepts are evolving and treatment options are becoming diversified, chiefly on the field of non-hormonal pharmacological therapy of sexual dysfunction. This review will examine the definitions of female sexual dysfunction, the etiology of the disorders in young breast cancer patients, the assessment methods, the non-pharmacological and pharmacological treatment options and the challenges that lie ahead. PMID:23819031

2013-01-01

230

Prevalence and psychological sequelae of self-reported childhood physical and sexual abuse in a general population sample of men and women  

Microsoft Academic Search

Objective: This study examined the prevalence and psychological sequelae of childhood sexual and physical abuse in adults from the general population.Method: A national sampling service generated a geographically stratified, random sample of 1,442 subjects from the United States. Subjects were mailed a questionnaire that included the Traumatic Events Survey (TES) [Traumatic Events Survey, Unpublished Psychological Test, Harbor-UCLA Medical Center, Los

John Briere; Diana M. Elliott

2003-01-01

231

CONSTRAINTS ON THE EVOLUTION OF MALES AND SEXUAL DIMORPHISM: FIELD ESTIMATES OF GENETIC ARCHITECTURE OF REPRODUCTIVE TRAITS IN THREE POPULATIONS OF GYNODIOECIOUS FRAGARIA VIRGINIANA  

Microsoft Academic Search

To understand how genetic constraints may limit the evolution of males and sexual dimorphism in a gynodioecious species, I conducted a quantitative genetic experiment in a gynodioecious wild strawberry, Fragaria virginiana. I estimated and compared genetic parameters (narrow-sense heritabilities, between-trait and between-sex genetic correlations, as well as phenotypic and genetic variance-covariance matrices) in the two sex morphs from three populations

Tia-Lynn Ashman

2003-01-01

232

Sexually coercive behavior following childhood maltreatment.  

PubMed

Child maltreatment is associated with adult sexually coercive behavior. The association may be causal or confounders that increase the risk of both childhood victimization and sexually coercive behavior might explain the observed links. We examined if childhood maltreatment was related to sexual coercion independently of familial (genetic or common family environment) risk factors, thereby addressing potential causality. Participants were 6,255 18 to 33-year-old twins from the Finnish population-based study "Genetics of Sex and Aggression" who responded to self-report questionnaires of child maltreatment and sexually coercive behavior. We used generalized estimating equations to elucidate risk of sexual coercion in maltreated compared to unrelated, non-maltreated individuals. To adjust for unmeasured familial factors, we used the co-twin control method and compared sexual coercion risk within maltreatment-discordant twin pairs. Further, we examined possible differential effects of maltreatment subtypes and compared mean differences in maltreatment summary scores between sexually coercive individuals and controls. Sexual coercion was moderately more common among individuals maltreated as children versus unrelated controls (38.3 vs. 22.8 %; age- and gender-adjusted odds ratio, aOR = 2.31, 95 % CI 1.75-3.05) and the risk increase remained similar within maltreatment-discordant twins (OR = 2.82, 95 % CI 1.42-5.61). Moreover, different maltreatment subtypes predicted sexual coercion equally well and effect sizes remained similar within discordant twin pairs. We conclude that associations between child maltreatment and sexual coercion are largely independent of shared familial confounds, consistent with a causal inference. Importantly, detection and targeted interventions for maltreated children should remain a priority to reduce societal sexually coercive behavior. PMID:24752790

Forsman, Mats; Johansson, Ada; Santtila, Pekka; Sandnabba, Kenneth; Långström, Niklas

2015-01-01

233

Sleep Patterns and Predictors of Disturbed Sleep in a Large Population of College Students  

Microsoft Academic Search

PurposeTo characterize sleep patterns and predictors of poor sleep quality in a large population of college students. This study extends the 2006 National Sleep Foundation examination of sleep in early adolescence by examining sleep in older adolescents.

Hannah G. Lund; Brian D. Reider; Annie B. Whiting; J. Roxanne Prichard

2010-01-01

234

Maximum body size among insular Komodo dragon populations covaries with large prey density  

Microsoft Academic Search

ABSTRACT This study documents,variation in maximum,body size of Komodo dragons (Varanus Komodoensis) among the 4 extant island populations, and compares an indirect measure of deer density, the major prey item for large dragons, to differences in

Tim S. Jessop; Thomas Madsen; Joanna Sumner; Heru Rudiharto; John A. Phillips; Claudio Ciofi

2006-01-01

235

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...

236

Population dynamics of large herbivores: variable recruitment with constant adult survival  

Microsoft Academic Search

Recent long-term studies of population ecology of large herbivorous mammals suggest that survival of prime-aged females varies little from year to year and across populations. Juvenile survival, on the other hand, varies considerably from year to year. The pattern of high and stable adult survival and variable juvenile survival is observed in contrasting environments, independently of the main proximal sources

Jean-Michel Gaillard; Marco Festa-Bianchet; Nigel Gilles Yoccoz

1998-01-01

237

High genetic variation in leopards indicates large and long-term stable effective population size  

Microsoft Academic Search

In this paper we employ recently developed statistical and molecular tools to analyse the population history of the Tanzanian leopard ( Panthera pardus ), a large solitary felid. Because of their solitary lifestyle little is known of their past or present population dynamics. Eighty-one individuals were scored at 18 microsatellite loci. Overall, levels of hetero- zygosity were high (0.77 ?

G. Spong; M. Johansson; M. Björklund

2000-01-01

238

Individual quality, early-life conditions, and reproductive success in contrasted populations of large herbivores  

Microsoft Academic Search

Variations among individuals in phenotypic quality and fitness often confound analyses of life-history strategies assessed at the population level. We used detailed long-term data from three populations of large herbivores with generation times ranging from four to nine years to quantify heterogeneity in individual quality among females, and to assess its influence on mean annual reproductive success over the lifetime

Sandra Hamel; Jean-Michel Gaillard; Marco Festa-Bianchet; Steeve D. Côté

2009-01-01

239

Lipoprotein lipase gene polymorphism, cholesterol subfractions and myocardial infarction in large samples of the general population  

Microsoft Academic Search

a ¨ Abstract Objective: Genetic variants of the lipoprotein lipase gene have been associated with dyslipidemia and coronary artery disease. However, data have been inconsistent and are mainly based on selected predominantly male patient groups. Methods: We evaluated the influence of the HindIII restriction fragment length polymorphism on lipid levels in the general population (1361 participants of a large population-based

Stephan R. Holmer; Christian Hengstenberg; Bjorn Mayer; Angela Doring; Hannelore Lowel; Susanne Engel; Hans-Werner Hense; Melanie Wolf; Gernot Klein; Gunter A. J. Riegger; Heribert Schunkert

240

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

Microsoft Academic Search

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

Rhona Feigenbaum; Estelle Weinstein; Efrem Rosen

1995-01-01

241

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

Microsoft Academic Search

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

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

2008-01-01

242

Interpersonal Mistreatment in the Workplace: The Interface and Impact of General Incivility and Sexual Harassment  

Microsoft Academic Search

This article examined the relationships and outcomes of behaviors falling at the interface of general and sexual forms of interpersonal mistreatment in the workplace. Data were collected with surveys of two different female populations (Ns = 833 and 1,425) working within a large public-sector organization. Findings revealed that general incivility and sexual harassment were related constructs, with gender harassment bridging

Sandy Lim; Lilia M. Cortina

2005-01-01

243

Age biases in a large HIV and sexual behaviour-related internet survey among MSM  

PubMed Central

Background Behavioural data from MSM are usually collected in non-representative convenience samples, increasingly on the internet. Epidemiological data from such samples might be useful for comparisons between countries, but are subject to unknown participation biases. Methods Self-reported HIV diagnoses from participants of the European MSM Internet Survey (EMIS) living in the Czech Republic, Germany, the Netherlands, Portugal, Sweden and the United Kingdom were compared with surveillance data, for both the overall diagnosed prevalence and for new diagnoses made in 2009. Country level prevalence and new diagnoses rates per 100 MSM were calculated based on an assumed MSM population size of 3% of the adult male population. Survey-surveillance discrepancies (SSD) for survey participation, diagnosed HIV prevalence and new HIV diagnoses were determined as ratios of proportions. Results are calculated and presented by 5-year age groups for MSM aged 15–64. Results Surveillance derived estimates of diagnosed HIV prevalence among MSM aged 15–64 ranged from 0.63% in the Czech Republic to 4.93% in the Netherlands. New HIV diagnoses rates ranged between 0.10 per 100 MSM in the Czech Republic and 0.48 per 100 in the Netherlands. Self-reported rates from EMIS were consistently higher, with prevalence ranging from 2.68% in the Czech Republic to 12.72% in the Netherlands, and new HIV diagnoses rates from 0.36 per 100 in Sweden to 1.44 per 100 in the Netherlands. Across age groups, the survey surveillance discrepancies (SSD) for new HIV diagnoses were between 1.93 in UK and 5.95 in the Czech Republic, and for diagnosed prevalence between 1.80 in Germany and 4.26 in the Czech Republic. Internet samples of MSM were skewed towards younger age groups when compared to an age distribution of the general adult male population. Survey-surveillance discrepancies (SSD) for EMIS participation were inverse u-shaped across the age range. The two HIV-related SSD were u- or j-shaped with higher values for the very young and for older MSM. The highest discrepancies between survey and surveillance data regarding HIV-prevalence were observed in the oldest age group in Sweden and the youngest age group in Portugal. Conclusion Internet samples are biased towards a lower median age because younger men are over-represented on MSM dating websites and therefore may be more likely to be recruited into surveys. Men diagnosed with HIV were over-represented in the internet survey, and increasingly so in the older age groups. A similar effect was observed in the age groups younger than 25 years. Self-reported peak prevalence and peak HIV diagnoses rates are often shifted to higher age groups in internet samples compared to surveillance data. Adjustment for age-effects on online accessibility should be considered when linking data from internet surveys with surveillance data. PMID:24020518

2013-01-01

244

Diversity lost: are all Holarctic large mammal species just relict populations?  

Microsoft Academic Search

Population genetic analyses of Eurasian wolves published recently in BMC Evolutionary Biology suggest that a major genetic turnover took place in Eurasian wolves after the Pleistocene. These results add to the growing evidence that large mammal species surviving the late Pleistocene extinctions nevertheless lost a large share of their genetic diversity. See research article http:\\/\\/www.biomedcentral.com\\/1471-2148\\/10\\/104

Michael Hofreiter; Ian Barnes

2010-01-01

245

Childhood trauma, sexually transmitted diseases and the perceived risk of contracting HIV in a drug using population.  

PubMed

This cross-sectional study explored the association among childhood trauma, sexually transmitted diseases histories, and perceived risk of contracting AIDS in 358 women and 338 male drug users in San Antonio, Texas. Women addicts were less educated, more likely to be in a common-law relationship, living with someone of the opposite sex or separated, and had lower incomes in comparison to men addicts. Significant findings were that women with increasing severity of abuse (emotional, physical, and sexual) histories as measured by the Childhood Trauma Questionnaire had increasing numbers of sexually transmitted diseases and perceptions of contracting HIV. These findings have implications for future directions in HIV and sexually transmitted disease intervention programs. PMID:16161726

Medrano, Martha A; Hatch, John P

2005-01-01

246

Sexual competitiveness and compatibility between mass-reared sterile flies and wild populations of Anastrepha Ludens (Diptera: Tephritidae) from different regions in Mexico  

SciTech Connect

The mass-reared colony of Anastrepha ludens (Loew) currently used in Mexico for suppression of the Mexican fruit fly has been in use for over 10 years. Sterile flies are released into a wide range of environmental conditions as part of an integrated area-wide approach to suppress diverse populations of this pest in the Mexican Republic. This paper assesses the performance of the sterile flies interacting with wild populations from the different environments. We investigated the sexual compatibility and competitiveness of the sterile flies when competing with wild populations from 6 representatives Mexican states: Nuevo Leon, Tamaulipas, Sinaloa, Nayarit, Michoacan, and Chiapas. Results show that the males of the wild populations differed in the time to the onset and peak of sexual activity. Nevertheless, the index of sexual isolation (ISI) reflected sexual compatibility between the populations and the mass-reared strain, indicating that the sterile individuals mate satisfactorily with the wild populations from the 6 states. The male relative performance index (MRPI) showed that the sterile male is as effective in copulating as the wild males. The female relative performance index (FRPI) reflected a general tendency for wild females to copulate in greater proportion than the sterile females, except for the strains from Tamaulipas and Chiapas. In general, the lower participation of the sterile females in copulation increases the possibilities of sterile males to mate with wild females. The relative sterility index (RSI) showed that the acceptance by wild females of the sterile males (25-55%) was similar to that of wild males. Females of the Chiapas strain showed the lowest acceptance of sterile males. Finally, the results obtained in the Fried test (which measures induced sterility in eggs) showed a competitiveness coefficient ranging from 0.2 to 0.5. This suggests that sterile males successfully compete and are compatible with flies from different geographic origins. (author) [Spanish] La colonia actualmente usada para controlar la mosca mexicana de la fruta, Anastrepha ludens (Loew), en Mexico tiene mas de 10 anos en cria masiva. Los insectos esteriles son liberados en una gran variedad de condiciones ambientales como parte de un control integrado para suprimir diversas poblaciones de esta plaga dentro de la Republica Mexicana. El objetivo de este documento esta dirigido a revisar el desempeno de las moscas esteriles frente a poblaciones silvestres procedentes de diferentes ambientes y para esto se realizaron comparaciones de compatibilidad y competitividad sexual de las moscas esteriles contra poblaciones silvestres de seis estados representativos de la Republica Mexicana: Nuevo Leon, Tamaulipas, Sinaloa, Nayarit, Michoacan y Chiapas. Los resultados obtenidos manifiestan diferencias en el horario de inicio de llamado y mayor actividad sexual del macho entre las moscas provenientes de cada estado. Sin embargo el indice de aislamiento (ISI) reflejo compatibilidad sexual entre la cepa de laboratorio y todas las poblaciones analizadas, indicando que los individuos esteriles pueden aparearse satisfactoriamente con las poblaciones silvestres de los seis estados. El indice de efectividad de apareamiento del macho (MRPI) reflejo de manera global que los machos esteriles son tan efectivos para copular como los silvestres. El indice de efectividad de apareamiento de la hembra (FRPI) reflejo que en la mayoria de los estados las hembras silvestres copularon en mayor proporcion que las hembras esteriles, excepto para las poblaciones de Tamaulipas y Chiapas. En general, la baja participacion de las hembras esteriles en el campo permitio al macho esteril ampliar su probabilidad de apareamiento con las hembras silvestres. En cuanto al indice de esterilidad relativa (RSI), observamos que la aceptacion de las hembras silvestres al macho esteril (25-55%) fue similar a la de los machos silvestres. Las hembras de la poblacion de Chiapas registro la menor aceptacion. Finalmente, los resultados obtenidos en la prueba de Fried, la cual determi

Orozco-Davila, D.; Hernandez, R.; Meza, S.; Dominguez, J. [Programa Moscamed Moscafrut-Desarrollo de Metodos, Central Poniente No. 14 altos-Esq. 2a Avenida Sur. CP 30700 Tapachula, Chiapas (Mexico)

2007-03-15

247

Extremely low genotypic diversity and sexual reproduction in isolated populations of the self-incompatible lily-of-the-valley (Convallaria majalis) and the role of the local forest environment  

PubMed Central

Background and Aims Clonal growth is a common phenomenon in plants and allows them to persist when sexual life-cycle completion is impeded. Very low levels of recruitment from seed will ultimately result in low levels of genotypic diversity. The situation can be expected to be exacerbated in spatially isolated populations of obligated allogamous species, as low genotypic diversities will result in low availability of compatible genotypes and low reproductive success. Populations of the self-incompatible forest herb lily-of-the-valley (Convallaria majalis) were studied with the aim of inferring the relative importance of sexual and asexual recruitment. Then the aim was to establish a relationship between genotypic diversity, sexual reproduction and the local forest environment. Methods Highly polymorphic microsatellite markers were used to investigate clonal diversities and population genetic structure of 20 populations of C. majalis in central Belgium. Key Results Most of the populations studied consisted of a single genotype and linkage disequilibrium within populations was high, manifesting clonal growth as the main mode of reproduction. A population consisting of multiple genotypes mainly occurred in locations with a thin litter layer and high soil phosphorus levels, suggesting environment-mediated sporadic recruitment from seed. Highly significant genetic differentiation indicated that populations are reproductively isolated. In agreement with the self-incompatibility of C. majalis, monoclonal populations showed very low or even absent fruit set. Conclusions Lack of sexual recruitment in spatially isolated C. majalis populations has resulted in almost monoclonal populations with reduced or absent sexual reproduction, potentially constraining their long-term persistence. The local forest environment may play an important role in mediating sexual recruitment in clonal forest plant species. PMID:20228091

Vandepitte, Katrien; Roldán-Ruiz, Isabel; Jacquemyn, Hans; Honnay, Olivier

2010-01-01

248

Constraints on the evolution of males and sexual dimorphism: field estimates of genetic architecture of reproductive traits in three populations of gynodioecious Fragaria virginiana.  

PubMed

To understand how genetic constraints may limit the evolution of males and sexual dimorphism in a gynodioecious species, I conducted a quantitative genetic experiment in a gynodioecious wild strawberry, Fragaria virginiana. I estimated and compared genetic parameters (narrow-sense heritabilities, between-trait and between-sex genetic correlations, as well as phenotypic and genetic variance-covariance matrices) in the two sex morphs from three populations grown in a common field garden. I measured pollen and ovule production per flower, petal size, fruit set, and flower number. My major findings are as follows. (1) The presence of a phenotypic trade-off between pollen production and fruit set in hermaphrodites reflects a negative genetic correlation in the narrow sense that is statistically significant when pooled across populations. (2) The main constraints on the evolution of males are low genetic variation for pollen per flower and strong positive correlations associated with ovule number (e.g., between pollen and ovules in hermaphrodites, and between ovules in hermaphrodites and females). (3) Traits with the lowest levels of sexual dimorphism (ovule number and flower number) have the highest between-sex genetic correlations suggesting that overlap in the expression of genes in the sex morphs constrains their independent evolution. (4) There are significant differences in G matrices between sex morphs but not among populations. However, evidence that male-female trait correlations in hermaphrodites were lower in populations with higher frequencies of females may indicate subtle changes in genetic architecture. PMID:14575323

Ashman, Tia-Lynn

2003-09-01

249

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

250

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

251

Effects of Large Woody Debris Addition on Stream Habitat and Brook Trout Populations in Appalachian Streams  

Microsoft Academic Search

Large woody debris (LWD) was added to eight streams in the central Appalachians of West Virginia to determine if stream habitat\\u000a could be enhanced and brook trout (Salvelinus fontinalis) populations increased. Brook trout populations were assessed one year prior to habitat manipulation and 3 years post-habitat\\u000a manipulation. LWD was added by felling approximately 15 trees per 300 m stream reach. Four of

John A. Sweka; Kyle J. Hartman

2006-01-01

252

TEMPORAL VARIATION IN FITNESS COMPONENTS AND POPULATION DYNAMICS OF LARGE HERBIVORES  

Microsoft Academic Search

? Abstract In large-herbivore populations, environmental variation and density dependence,co-occur and have similar effects on various fitness components.,Our re- view aims to quantify the temporal variability of fitness components,and examine,how that variability affects changes,in population,growth,rates. Regardless of the source of variation, adult female survival shows little year-to-year variation [coefficient of variation (CV 30%). Old females show,senescence,in both survival and reproduction.

J.-M. Gaillard; M. Festa-Bianchet; N. G. Yoccoz; A. Loison; C. Toigo

2000-01-01

253

Adaptive tracking-type games for coupled large population ARMAX systems  

Microsoft Academic Search

Distributed adaptive tracking-type games is investigated for large population stochastic multi-agent systems. The dynamics of each agent is described by ARMAX model with unknown structure parameters and unknown coupled terms. The performance index has an unknown population state average (PSA) term. In order to deal with the uncertainties, the extended least-squares algorithm is used to estimate the unknown parameters, and

Qiang Zhang; Ji-Feng Zhang

2010-01-01

254

Sexual Harassment and Sexual Bulllying  

MedlinePLUS

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

255

Challenges of cardiac image analysis in large-scale population-based studies.  

PubMed

Large-scale population-based imaging studies of preclinical and clinical heart disease are becoming possible due to the advent of standardized robust non-invasive imaging methods and infrastructure for big data analysis. This gives an exciting opportunity to gain new information about the development and progression of heart disease across population groups. However, the large amount of image data and prohibitive time required for image analysis present challenges for obtaining useful derived data from the images. Automated analysis tools for cardiac image analysis are only now becoming available. This paper reviews the challenges and possible solutions to the analysis of big imaging data in population studies. We also highlight the potential of recent large epidemiological studies using cardiac imaging to discover new knowledge on heart health and well-being. PMID:25648627

Medrano-Gracia, Pau; Cowan, Brett R; Suinesiaputra, Avan; Young, Alistair A

2015-03-01

256

Seasonal components of avian population change: joint analysis of two large-scale monitoring programs.  

PubMed

We present a combined analysis of data from two large-scale surveys of bird populations. The North American Breeding Bird Survey is conducted each summer; the Christmas Bird Count is conducted in early winter. The temporal staggering of these surveys allows investigation of seasonal components of population change, which we illustrate with an examination of the effects of severe winters on the Carolina Wren (Thryothorus ludovicianus). Our analysis uses a hierarchical log-linear model with controls for survey-specific sampling covariates. Temporal change in population size is modeled seasonally, with covariates for winter severity. Overall, the winter-spring seasons are associated with 82% of the total population variation for Carolina Wrens, and an additional day of snow cover during winter-spring is associated with an incremental decline of 1.1% of the population. PMID:17489453

Link, William A; Sauer, John R

2007-01-01

257

Resolved Stellar Populations with MAD: Preparing for the Era of Extremely Large Telescopes  

NASA Astrophysics Data System (ADS)

Deep images in J, H and Ks filters using the Multi-conjugate Adaptive optics Demonstrator (MAD) on the VLT have been made of a region of the Large Magellanic Cloud near the globular cluster NGC 1928. Our aim was to assess if accurate photometry could be carried out down to faint limits over the whole MAD field of view. In addition we tested how accurate a basic analysis of the properties of the stellar population could be made using the near-infrared MAD photometry, compared to the Hubble Space Telescope optical photometry. This study has implications for understanding the issues involved in Extremely Large Telescope imaging of resolved stellar populations.

Fiorentino, G.; Tolstoy, E.; Diolaiti, E.; Valenti, E.; Cignoni, M.; Mackey, A. D.

2012-03-01

258

PyPop update - a software pipeline for large-scale multilocus population genomics  

PubMed Central

Population genetic statistics from multilocus genotype data inform our understanding of the patterns of genetic variation and their implications for evolutionary studies, generally, and human disease studies in particular. In any given population one can estimate haplotype frequencies, identify deviation from Hardy-Weinberg equilibrium, test for balancing or directional selection, and investigate patterns of linkage disequilibrium. Existing software packages are oriented primarily toward the computation of such statistics on a population-by-population basis, not on comparisons among populations and across different statistics. We developed PyPop (Python for Population Genomics) to facilitate the analyses of population genetic statistics across populations and the relationships among different statistics within and across populations. PyPop is an an open-source framework for performing large-scale population genetic analyses on multilocus genotype data. It computes the statistics described above, among others. PyPop deploys a standard Extensible Markup Language (XML) output format and can integrate the results of multiple analyses on various populations that were performed at different times into a common output format that can be read into a spreadsheet. The XML output format allows PyPop to be embedded as part of a larger analysis pipeline. Originally developed to analyze the highly polymorphic genetic data of the human leukocyte antigen region of the human genome, PyPop has applicability to any kind of multilocus genetic data. It is the primary analysis platform for analyzing data collected for the Anthropological component of the 13th and 14th International Histocompatibility Workshops. PyPop has also been successfully used in studies by our group, with collaborators, and in publications by several independent research teams. PMID:17445199

Lancaster, Alex K.; Single, Richard M.; Solberg, Owen D.; Nelson, Mark P.; Thomson, Glenys

2015-01-01

259

Health benefits of legal services for criminalized populations: the case of people who use drugs, sex workers and sexual and gender minorities.  

PubMed

Social exclusion and legal marginalization are important determinants of health outcomes for people who use illicit drugs, sex workers, and persons who face criminal penalties because of homosexuality or transgenderism. Incarceration may add to the health risks associated with police repression and discrimination for these persons. Access to legal services may be essential to positive health outcomes in these populations. Through concrete examples, this paper explores types of legal problems and legal services linked to health outcomes for drug users, sex workers, and sexual minorities and makes recommendations for donors, legal service providers, and civil society organizations. PMID:21105945

Csete, Joanne; Cohen, Jonathan

2010-01-01

260

Sexual dimorphism in a dioecious population of the wind-pollinated herb Mercurialis annua: the interactive effects of resource availability and competition  

PubMed Central

Background and Aims Male-biased sex allocation commonly occurs in wind-pollinated hermaphroditic plants, and is often positively associated with size, notably in terms of height. Currently, it is not well established whether a corresponding pattern holds for dioecious plants: do males of wind-pollinated species exhibit greater reproductive allocation than females? Here, sexual dimorphism is investigated in terms of life history trade-offs in a dioecious population of the wind-pollinated ruderal herb Mercurialis annua. Methods The allocation strategies of males and females grown under different soil nutrient availability and competitive (i.e. no, male or female competitor) regimes were compared. Key Results Male reproductive allocation increased disproportionately with biomass, and was greater than that of females when grown in rich soils. Sexual morphs differentially adjusted their reproductive allocation in response to local environmental conditions. In particular, males reduced their reproductive allocation in poor soils, whereas females increased theirs, especially when competing with another female rather than growing alone. Finally, males displayed smaller above-ground vegetative sizes than females, but neither nutrient availability nor competition had a strong independent effect on relative size disparities between the sexes. Conclusions Selection appears to favour plasticity in reproductive allocation in dioecious M. annua, thereby maintaining a relatively constant size hierarchy between sexual morphs. In common with other dioecious species, there seems to be little divergence in the niches occupied by males and females of M. annua. PMID:21385775

Hesse, Elze; Pannell, John R.

2011-01-01

261

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

PubMed

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

Delph, Lynda F; Herlihy, Christopher R

2012-04-01

262

Ecological risk assessment in a large river-reservoir. 6: Bioindicators of fish population health  

Microsoft Academic Search

Spatial distribution of contaminants in the sediments and biota of a large reservoir ecosystem were related to a variety of biological responses in fish populations and communities to determine possible relationships between contaminant loading in the environment and fish health. Much of the contaminant inventory in the Clinch River\\/Watts Bar Reservoir (CR\\/WBR) system has originated from three US Department of

S. Marshall Adams; Mark S. Bevelhimer; Daniel A. Levine; Swee J. Teh

1999-01-01

263

A large percentage of the population in Bangladesh is highly exposed to arsenic and  

E-print Network

A large percentage of the population in Bangladesh is highly exposed to arsenic and manganese to be toxic (Institute of Medicine Food and Nutrition Board 2002). Manganese is best characterized are reconstructed from a repro- ductive history of women in the Health Effects of Arsenic Longitudinal Study (HEALS

van Geen, Alexander

264

Birth seasonality and calf mortality in a large population of Asian elephants  

E-print Network

Birth seasonality and calf mortality in a large population of Asian elephants Hannah S. Mumby1 elephants. Correspondence Hannah S. Mumby, Department of Animal and Plant Sciences, Alfred Denny Building)114 2220002; E-mail: h.mumby@sheffield.ac.uk Funding Information The Myanmar Timber Elephant project is funded

Lummaa, Virpi

265

IMPLICATIONS: GHOST GALAXIES 3 --There may be a large population of dark galaxies that contain  

E-print Network

IMPLICATIONS: GHOST GALAXIES 3 -- There may be a large population of dark galaxies that contain too few stars to be discovered. They may outnumber all luminous galaxies combined. Reasons: ffl Astronomers continue to discover faint galaxies. Clearly we have not found all of them. The fraction of all

Kormendy, John

266

Global distribution of large lunar craters: implications for resurfacing and impactor populations.  

PubMed

By using high-resolution altimetric measurements of the Moon, we produced a catalog of all impact craters ?20 kilometers in diameter on the lunar surface and analyzed their distribution and population characteristics. The most-densely cratered portion of the highlands reached a state of saturation equilibrium. Large impact events, such as Orientale Basin, locally modified the prebasin crater population to ~2 basin radii from the basin center. Basins such as Imbrium, Orientale, and Nectaris, which are important stratigraphic markers in lunar history, are temporally distinguishable on the basis of crater statistics. The characteristics of pre- and postmare crater populations support the hypothesis that there were two populations of impactors in early solar system history and that the transition occurred near the time of the Orientale Basin event. PMID:20847265

Head, James W; Fassett, Caleb I; Kadish, Seth J; Smith, David E; Zuber, Maria T; Neumann, Gregory A; Mazarico, Erwan

2010-09-17

267

Sexual Abuse Histories of Youth in Child Welfare Residential Treatment Centers: Analysis of the Odyssey Project Population  

ERIC Educational Resources Information Center

This multi-site examination of sexual abuse histories of youth in residential treatment centers asked, for the sample as a whole and by youth's gender: (a) How many perpetrators did each youth have? (b) What was the gender of the perpetrator? (c) What proportion of youth was abused by family members? (d) What proportion of youth was abused in a…

Baker, Amy J. L.; Curtis, Patrick A.; Papa-Lentini, Cynthia

2006-01-01

268

Sexually transmissible infections among female sex workers: an international review with an emphasis on hard-to-access populations  

Microsoft Academic Search

Background: Women who work commercially in sex work (female sex workers (FSW)) are considered a high-risk group for sexually transmissible infections (STI), yet the level of reported pathogens varies in studies around the world. This study reviewed STI rates reported in 42 studies of FSW around the world published between 1995 and 2006 and analysed the trends and types of

269

Sexual dysfunction and prostatitis  

Microsoft Academic Search

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

Hossein Sadeghi-Nejad; Allen Seftel

2006-01-01

270

Behavioral treatment approaches for methamphetamine dependence and HIV-related sexual risk behaviors among urban gay and bisexual men  

Microsoft Academic Search

Background:Methamphetamine-dependent gay and bisexual men (GBM) are at high risk for HIV transmission, largely due to drug-associated sexual risk behaviors. This project evaluated the efficacy of four behavioral drug abuse treatments for reducing methamphetamine use and sexual risk behaviors among this population.

Steven Shoptaw; Cathy J. Reback; James A. Peck; Xiaowei Yang; Erin Rotheram-Fuller; Sherry Larkins; Rosemary C. Veniegas; Thomas E. Freese; Christopher Hucks-Ortiz

2005-01-01

271

Sexual orientation of men with pathological gambling: prevalence and psychiatric comorbidity in a treatment-seeking sample  

Microsoft Academic Search

Although gay men represent a high-risk group for psychiatric illness and impairment, they are largely an understudied population. The purpose of the present study was to examine the sexual orientation and clinical correlates of men with pathological gambling (PG). Sexual orientation was assessed in 105 men presenting with PG. Gay and bisexual men with PG were compared with heterosexual men

Jon E. Grant; Marc N. Potenza

2006-01-01

272

On the Etiology of Sexual Dysfunction  

ERIC Educational Resources Information Center

Lack of consideration of the sexually functional population has led to misconceptions about causes of sexual dysfunction functioning. Automatic functioning can mask effects of pathogenic influences on sexuality, making these effects appear random, confounding etiological issues and creating the belief that causes of sexual dysfunction and disorder…

Apfelbaum, Bernard

1977-01-01

273

Detecting sexual conflict and sexually antagonistic coevolution  

PubMed Central

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

Rowe, Locke; Day, Troy

2006-01-01

274

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

275

Managing Natural and Reintroduced Rare Plant Populations within a Large Government Reservation  

SciTech Connect

California is home to many large government reservations that have been in existence for decades. Many of these reservations were formed to support various Department of Defense and Department of Energy national defense activities. Often, only a very small percentage of the reservation is actively used for programmatic activities, resulting in large areas of intact habitat. In some cases, this has benefited rare plant populations, as surrounding lands have been developed for residential or industrial use. However, land management activities such as the suppression or active use of fire and other disturbance (such as fire trail grading) can also work to either the detriment or benefit of rare plant populations at these sites. A management regime that is beneficial to the rare plant populations of interest and is at best consistent with existing site programmatic activities, and at a minimum does not impact such activities, has the best potential for a positive outcome. As a result, some species may be 'difficult' while others may be 'easy' to manage in this context, depending on how closely the species biological requirements match the programmatic activities on the reservation. To illustrate, we compare and contrast two rare annual plant species found at Lawrence Livermore National Laboratory's Site 300. Although several populations of Amsinckia grandiflora have been restored on the site, and all populations are intensively managed, this species continues to decline. In contrast, Blepharizonia plumosa appears to take advantage of the annual controlled burns conducted on the site, and is thriving.

Carlsen, T M; Paterson, L E; Alfaro, T M

2009-07-15

276

Disease-mediated inbreeding depression in a large, open population of cooperative crows.  

PubMed

Disease-mediated inbreeding depression is a potential cost of living in groups with kin, but its general magnitude in wild populations is unclear. We examined the relationships between inbreeding, survival and disease for 312 offspring, produced by 35 parental pairs, in a large, open population of cooperatively breeding American crows (Corvus brachyrhynchos). Genetic analyses of parentage, parental relatedness coefficients and pedigree information suggested that 23 per cent of parental dyads were first- or second-order kin. Heterozygosity-heterozygosity correlations suggested that a microsatellite-based index of individual heterozygosity predicted individual genome-wide heterozygosity in this population. After excluding birds that died traumatically, survival probability was lower for relatively inbred birds during the 2-50 months after banding: the hazard rate for the most inbred birds was 170 per cent higher than that for the least inbred birds across the range of inbreeding index values. Birds that died with disease symptoms had higher inbreeding indices than birds with other fates. Our results suggest that avoidance of close inbreeding and the absence of inbreeding depression in large, open populations should not be assumed in taxa with kin-based social systems, and that microsatellite-based indices of individual heterozygosity can be an appropriate tool for examining the inbreeding depression in populations where incest and close inbreeding occur. PMID:19324784

Townsend, Andrea K; Clark, Anne B; McGowan, Kevin J; Buckles, Elizabeth L; Miller, Andrew D; Lovette, Irby J

2009-06-01

277

4P: fast computing of population genetics statistics from large DNA polymorphism panels  

PubMed Central

Massive DNA sequencing has significantly increased the amount of data available for population genetics and molecular ecology studies. However, the parallel computation of simple statistics within and between populations from large panels of polymorphic sites is not yet available, making the exploratory analyses of a set or subset of data a very laborious task. Here, we present 4P (parallel processing of polymorphism panels), a stand-alone software program for the rapid computation of genetic variation statistics (including the joint frequency spectrum) from millions of DNA variants in multiple individuals and multiple populations. It handles a standard input file format commonly used to store DNA variation from empirical or simulation experiments. The computational performance of 4P was evaluated using large SNP (single nucleotide polymorphism) datasets from human genomes or obtained by simulations. 4P was faster or much faster than other comparable programs, and the impact of parallel computing using multicore computers or servers was evident. 4P is a useful tool for biologists who need a simple and rapid computer program to run exploratory population genetics analyses in large panels of genomic data. It is also particularly suitable to analyze multiple data sets produced in simulation studies. Unix, Windows, and MacOs versions are provided, as well as the source code for easier pipeline implementations. PMID:25628874

Benazzo, Andrea; Panziera, Alex; Bertorelle, Giorgio

2015-01-01

278

4P: fast computing of population genetics statistics from large DNA polymorphism panels.  

PubMed

Massive DNA sequencing has significantly increased the amount of data available for population genetics and molecular ecology studies. However, the parallel computation of simple statistics within and between populations from large panels of polymorphic sites is not yet available, making the exploratory analyses of a set or subset of data a very laborious task. Here, we present 4P (parallel processing of polymorphism panels), a stand-alone software program for the rapid computation of genetic variation statistics (including the joint frequency spectrum) from millions of DNA variants in multiple individuals and multiple populations. It handles a standard input file format commonly used to store DNA variation from empirical or simulation experiments. The computational performance of 4P was evaluated using large SNP (single nucleotide polymorphism) datasets from human genomes or obtained by simulations. 4P was faster or much faster than other comparable programs, and the impact of parallel computing using multicore computers or servers was evident. 4P is a useful tool for biologists who need a simple and rapid computer program to run exploratory population genetics analyses in large panels of genomic data. It is also particularly suitable to analyze multiple data sets produced in simulation studies. Unix, Windows, and MacOs versions are provided, as well as the source code for easier pipeline implementations. PMID:25628874

Benazzo, Andrea; Panziera, Alex; Bertorelle, Giorgio

2015-01-01

279

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

280

fastSTRUCTURE: Variational Inference of Population Structure in Large SNP Data Sets  

PubMed Central

Tools for estimating population structure from genetic data are now used in a wide variety of applications in population genetics. However, inferring population structure in large modern data sets imposes severe computational challenges. Here, we develop efficient algorithms for approximate inference of the model underlying the STRUCTURE program using a variational Bayesian framework. Variational methods pose the problem of computing relevant posterior distributions as an optimization problem, allowing us to build on recent advances in optimization theory to develop fast inference tools. In addition, we propose useful heuristic scores to identify the number of populations represented in a data set and a new hierarchical prior to detect weak population structure in the data. We test the variational algorithms on simulated data and illustrate using genotype data from the CEPH–Human Genome Diversity Panel. The variational algorithms are almost two orders of magnitude faster than STRUCTURE and achieve accuracies comparable to those of ADMIXTURE. Furthermore, our results show that the heuristic scores for choosing model complexity provide a reasonable range of values for the number of populations represented in the data, with minimal bias toward detecting structure when it is very weak. Our algorithm, fastSTRUCTURE, is freely available online at http://pritchardlab.stanford.edu/structure.html. PMID:24700103

Raj, Anil; Stephens, Matthew; Pritchard, Jonathan K.

2014-01-01

281

Understanding sexual harassment using aggregate construct models.  

PubMed

Sexual harassment has received a substantial amount of empirical attention over the past few decades, and this research has consistently shown that experiencing these behaviors has a detrimental effect on employees' well-being, job attitudes, and behaviors at work. However, these findings, and the conclusions that are drawn from them, make the implicit assumption that the empirical models used to examine sexual harassment are properly specified. This article presents evidence that properly specified aggregate construct models are more consistent with theoretical structures and definitions of sexual harassment and can result in different conclusions about the nomological network of harassment. Results from 3 large samples, 2 military and 1 from a civilian population, are used to illustrate the differences between aggregate construct and reflective indicator models of sexual harassment. These analyses suggested that the factor structure and the nomological network of sexual harassment differ when modeling harassment as an aggregate construct. The implications of these results for the continued study of sexual harassment are discussed. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:25265486

Nye, Christopher D; Brummel, Bradley J; Drasgow, Fritz

2014-11-01

282

Sexual Assault  

MedlinePLUS

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

283

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 ...

284

Sexual functioning in a population-based study of men aged 40–69 years: the good news  

Microsoft Academic Search

The aim of the study was to provide cross-sectional data on age-related sexual functioning of men aged 40-69 y. The study was a randomised age-stratified community-based sample survey. In all, 799 men from two comparable middle-sized areas of Belgium participated in the study. Trained male nurses visited each participant at home and conducted a structured interview during which the participants

P Enzlin; R Mak; F Kittel; K Demyttenaere

2004-01-01

285

Comparison of three replication strategies in complex multicellular organisms: Asexual replication, sexual replication with identical gametes, and sexual replication with distinct sperm and egg gametes  

NASA Astrophysics Data System (ADS)

This paper studies the mutation-selection balance in three simplified replication models. The first model considers a population of organisms replicating via the production of asexual spores. The second model considers a sexually replicating population that produces identical gametes. The third model considers a sexually replicating population that produces distinct sperm and egg gametes. All models assume diploid organisms whose genomes consist of two chromosomes, each of which is taken to be functional if equal to some master sequence, and defective otherwise. In the asexual population, the asexual diploid spores develop directly into adult organisms. In the sexual populations, the haploid gametes enter a haploid pool, where they may fuse with other haploids. The resulting immature diploid organisms then proceed to develop into mature organisms. Based on an analysis of all three models, we find that, as organism size increases, a sexually replicating population can only outcompete an asexually replicating population if the adult organisms produce distinct sperm and egg gametes. A sexual replication strategy that is based on the production of large numbers of sperm cells to fertilize a small number of eggs is found to be necessary in order to maintain a sufficiently low cost for sex for the strategy to be selected for over a purely asexual strategy. We discuss the usefulness of this model in understanding the evolution and maintenance of sexual replication as the preferred replication strategy in complex, multicellular organisms.

Tannenbaum, Emmanuel

2008-01-01

286

Dynamics of the time to the most recent common ancestor in a large branching population  

E-print Network

If we follow an asexually reproducing population through time, then the amount of time that has passed since the most recent common ancestor (MRCA) of all current individuals lived will change as time progresses. The resulting stochastic process has been studied previously when the population has a constant large size and evolves via the diffusion limit of standard Wright-Fisher dynamics. We investigate cases in which the population varies in size and evolves according to a class of models that includes suitably conditioned $(1+\\beta)$-stable continuous state branching processes (in particular, it includes the conditioned Feller continuous state branching process). We also consider the discrete time Markov chain that tracks the MRCA age just before and after its successive jumps. We find transition probabilities for both the continuous and discrete time processes, determine when these processes are transient and recurrent, and compute stationary distributions when they exist. We also introduce a new family of...

Evans, Steven N

2008-01-01

287

Sexual functioning following renal transplantation.  

PubMed

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

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

2003-11-01

288

A simple, semi-deterministic approximation to the distribution of selective sweeps in large populations.  

PubMed

In large populations, the distribution of the trajectory of allele frequencies under selection and genetic drift approaches a semi-deterministic behavior: a deterministic trajectory started and ended at stochastic boundary values. This provides simple yet accurate approximations for the distribution of allelic frequencies over time (conditional on fixation), and of extinction and fixation times, for both hard and soft sweeps, and under arbitrary inbreeding and dominance. PMID:25724404

Martin, Guillaume; Lambert, Amaury

2015-05-01

289

On the Spatial Distribution of Stellar Populations in the Large Magellanic Cloud  

E-print Network

We measure the angular correlation function of stars in a region of the Large Magellanic Cloud (LMC) that spans 2 degrees by 1.5 degrees. We find that the correlation functions of stellar populations are represented well by exponential functions of the angular separation for separations between 2 and 40 arcmin (corresponding to ~ 30 pc and 550 pc for an LMC distance of 50 kpc). The inner boundary is set by the presence of distinct, highly correlated structures, which are the more familiar stellar clusters, and the outer boundary is set by the observed region's size and the presence of two principal centers of star formation within the region. We also find that the normalization and scale length of the correlation function changes systematically with the mean age of the stellar population. The existence of positive correlation at large separations (~300 pc), even in the youngest population, argues for large-scale hierarchical structure in current star formation. The evolution of the angular correlation toward lower normalizations and longer scale lengths with stellar age argues for the dispersion of stars with time. We show that a simple, stochastic, self-propagating star formation model is qualitatively consistent with this behavior of the correlation function.

Jason Harris; Dennis Zaritsky

1999-02-20

290

Psychosocial pathways to sexual dysfunction among female inmates.  

PubMed

Although health surveys on sexual issues during incarceration have shown that women report having engaged in sexual activities while in prison, studies on sexual functioning in female inmates have been largely dismissed. This study aimed to assess sexual functioning among incarcerated women and determine the psychometric and sociodemographic features that are possibly related to the risk of sexual dysfunction. This was a cross-sectional study conducted inside a penitentiary for women in São Paulo, Brazil. From June 2006 to June 2010, 315 inmates convicted of robbery or homicide were recruited. High risk of female sexual dysfunction (HRFSD) was measured using the Female Sexual Function Index and participants were also evaluated for alcohol and drug misuse, impulsiveness, depressive symptoms, and psychosocial features. Descriptive statistics and multivariate logistic regression were utilized to analyze the data. Among the participants, 253 (80.32 %) met the criteria for HRFSD. Older age, total time of imprisonment, and depressive symptoms were related to a higher risk, while the status of being married, being Black, having sexual relations with other inmates, and receiving conjugal visits were associated with a lower risk. As only 110 (34.92 %) inmates admitted to having sexual relationships inside prison, we evaluated this sub-sample separately. For this sub-sample, 61 (55.45 %) women met the criteria for HRFSD and the main factors associated with this risk were total time of imprisonment and depressive symptoms. Incarcerated women are uniquely vulnerable because they often have histories of deprivation and violence stemming from multiple sources and experience considerable psychological symptoms as a consequence of imprisonment. With the affected population rarely receiving psychosocial management for sexual dysfunction, service delivery efforts should be intensified to target this high-risk population. PMID:24496787

Baltieri, Danilo Antonio

2014-08-01

291

Patterns of Variation at Ustilago maydis Virulence Clusters 2A and 19A Largely Reflect the Demographic History of Its Populations  

PubMed Central

The maintenance of an intimate interaction between plant-biotrophic fungi and their hosts over evolutionary times involves strong selection and adaptative evolution of virulence-related genes. The highly specialised maize pathogen Ustilago maydis is assigned with a high evolutionary capability to overcome host resistances due to its high rates of sexual recombination, large population sizes and long distance dispersal. Unlike most studied fungus-plant interactions, the U. maydis – Zea mays pathosystem lacks a typical gene-for-gene interaction. It exerts a large set of secreted fungal virulence factors that are mostly organised in gene clusters. Their contribution to virulence has been experimentally demonstrated but their genetic diversity within U. maydis remains poorly understood. Here, we report on the intraspecific diversity of 34 potential virulence factor genes of U. maydis. We analysed their sequence polymorphisms in 17 isolates of U. maydis from Europe, North and Latin America. We focused on gene cluster 2A, associated with virulence attenuation, cluster 19A that is crucial for virulence, and the cluster-independent effector gene pep1. Although higher compared to four house-keeping genes, the overall levels of intraspecific genetic variation of virulence clusters 2A and 19A, and pep1 are remarkably low and commensurate to the levels of 14 studied non-virulence genes. In addition, each gene is present in all studied isolates and synteny in cluster 2A is conserved. Furthermore, 7 out of 34 virulence genes contain either no polymorphisms or only synonymous substitutions among all isolates. However, genetic variation of clusters 2A and 19A each resolve the large scale population structure of U. maydis indicating subpopulations with decreased gene flow. Hence, the genetic diversity of these virulence-related genes largely reflect the demographic history of U. maydis populations. PMID:24887029

Kellner, Ronny; Hanschke, Christian; Begerow, Dominik

2014-01-01

292

Large-scale natural disturbance alters genetic population structure of the sailfin molly, Poecilia latipinna.  

PubMed

Many inferences about contemporary rates of gene flow are based on the assumption that the observed genetic structure among populations is stable. Recent studies have uncovered several cases in which this assumption is tenuous. Most of those studies have focused on the effects that regular environmental fluctuations can have on genetic structure and gene flow patterns. Occasional catastrophic disturbances could also alter either the distribution of habitat or the spatial distribution of organisms in a way that affects population structure. However, evidence of such effects is sparse in the literature because it is difficult to obtain. Hurricanes, in particular, have the potential to exert dramatic effects on population structure of organisms found on islands or coral reefs or in near shore and coastal habitats. Here we draw on a historic genetic data set and new data to suggest that the genetic structure of sailfin molly (Poecilia latipinna) populations in north Florida was altered dramatically by an unusually large and uncommon type of storm surge associated with Hurricane Dennis in 2005. We compare the spatial pattern of genetic variation in these populations after Hurricane Dennis to the patterns described in an earlier study in this same area. We use comparable genetic data from another region of Florida, collected in the same two periods, to estimate the amount of change expected from typical temporal variation in population structure. The comparative natural history of sailfin mollies in these two regions indicates that the change in population structure produced by the storm surge is not the result of many local extinctions with recolonization from a few refugia but emerged from a pattern of mixing and redistribution. PMID:23348779

Apodaca, Joseph J; Trexler, Joel C; Jue, Nathaniel K; Schrader, Matthew; Travis, Joseph

2013-02-01

293

Evidence for an Intervening Stellar Population Toward the Large Magellanic Cloud  

E-print Network

We identify a vertical extension of the red clump stars in the color magnitude diagram (CMD) of a section of the Large Magellanic Cloud (LMC). After subtracting the principal red clump component, we find a peak in the residual stellar distribution that is ~ 0.9 mag brighter than the peak of the principal red clump distribution. We consider and reject the following possible explanations for this population: inhomogeneous reddening, Galactic disk stars, random blends of red clump stars, correlated blends of red clump stars (binaries), evolution of the red clump stars, and red clump stars from a younger LMC stellar population. Combinations of these effects cannot be ruled out as the origin of this stellar population. A natural interpretation of this new population is that it consists of red clump stars that are closer to us than those in the LMC. We find corroborating evidence for this interpretation in Holtzman et al.'s (1997) Hubble Space Telescope CMD of the LMC field stars. The derived distance and projected angular surface density of these stars relative to the LMC stars (<~ 5 to 7%) are consistent with (1) models that attribute the observed microlensing lensing optical depth (Alcock et al. 1997) to a distinct foreground stellar population (Zhao 1997) and (2) tidal models of the interaction between the LMC and the Milky Way (Lin, Jones, & Klemola 1995). We conclude that the standard assumption of a smoothly distributed halo population out to the LMC cannot be substantiated without at least a detailed understanding of red clump stellar evolution, binary fractions, binary mass ratios, the spatial correlation of stars within the LMC, possible variations in the stellar populations of satellite galaxies, and differential reddening - all of which are highly complex.

Dennis Zaritsky; D. N. C. Lin

1997-09-06

294

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

295

Multivariate sexual selection in a rapidly evolving speciation phenotype  

PubMed Central

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

Oh, Kevin P.; Shaw, Kerry L.

2013-01-01

296

Sexual behaviour after antiretroviral therapy initiation in female sex workers and HIV-positive patients from the general population, Cotonou, Benin.  

PubMed

From September 2008 to December 2011, we enrolled and followed-up 247 HIV-negative, 88 untreated and 32 treated HIV-positive female sex workers (FSWs), as well as 238 untreated and 115 treated HIV-positive patients from the general population (GP) of Cotonou, Benin. We wanted to assess the effect of antiretroviral therapy (ART) on sexual risk-taking in FSWs and patients from the GP. We used multivariate log binomial regression models for repeated measures to compare risky behaviours reported during pre-ART and post-ART visits and we performed linear time-trend analyses to assess changes in condom use in all five groups. At 58.8% of pre-ART and 45.3% of post-ART visits (adjusted p-value=0.293), treated FSWs have reported ?16 clients during the last week of work. Inconsistent condom use with clients over the same period decreased by more than 50% (from 20.7 to 10.0%, adjusted p-value=0.082). In treated patients from the GP, inconsistent condom use with regular partners during the last four months was reported at 52.8% of pre-ART and 53.5% of post-ART visits (p=0.778). Reported casual sex was stable (36.8% versus 38.7%, adjusted p-value=0.924). In linear time-trend analyses, there was a significant downward trend in inconsistent condom use at the early stage of the study and stability thereafter in all HIV-negative and HIV-positive FSWs. There was no negative alteration in sexual behaviour following ART initiation either inpatients from the GP or in FSWs. The results underscore the key role of concomitant sexual risk-reduction strategies. PMID:23438011

Diabaté, Souleymane; Chamberland, Annie; Zannou, Djimon M; Geraldo, Nassirou; Azon-Kouanou, Angèle; Massinga-Loembé, Marguérite; Ahomadégbé, Christelle; Labbé, Annie-Claude; Tremblay, Cécile; Alary, Michel

2013-01-01

297

Reproductive and resource benefits to large female body size in a mammal with female-biased sexual size dimorphism  

SciTech Connect

Factors underlying the evolution of female-biased sexual size dimorphism in mammals are poorly understood. In an effort to better understand these factors we tested whether larger female southern flying squirrels, Glaucomys volans, gained reproductive advantages (larger litters or more male mates) and direct resource benefits, such as larger home ranges or access to more food (i.e. mast-producing trees). As dimorphism can vary with age in precocial breeding species, we compared females during their first reproduction and during a subsequent breeding attempt. Females were not significantly larger or heavier than males at first reproduction, but became about 7% heavier and 22% larger than males at subsequent breeding. Larger females produced larger litters and had home ranges containing a greater proportion of upland hardwood trees. Female body size was not associated with either multiple male mating or home range size, but females with larger home ranges had higher indexes of body condition. Females in precocial breeding flying squirrels initiate reproduction before sexual size dimorphism is evident, and thus, may be allocating resources to both reproduction and growth simultaneously, or delaying growth entirely. Larger females produce more pups and have access to more food resources. Thus, selection for increased female size may partly explain how female-biased sexual size dimorphism is maintained in this species.

Fokidis, H.B., T.S. Risch and T.C. Glenn

2007-01-01

298

Population Genetic Structure of Titanotrichum oldhamii (Gesneriaceae), a Subtropical Bulbiliferous Plant with Mixed Sexual and Asexual Reproduction  

PubMed Central

• Background and Aims Titanotrichum oldhamii is a monotypic genus distributed in Taiwan, adjacent regions of China and the Ryukyu Isands of Japan. Its conservation status is vulnerable as most populations are small and widely scattered. Titanotrichum has a mixed system of reproduction with vegetative bulbils and seeds. The aim of this study was to understand the population genetic structure of Titanotrichum in relation to its specific reproductive behaviour and to determine possible implications for conservation strategies. • Methods After an extensive inventory of most wild populations of Titanotrichum in East Asia, samples from 25 populations within its major distribution were carried out utilizing RAPD and inter?SSR molecular fingerprinting analysis. • Key Results The findings support the conclusion that many populations reproduce predominantly asexually but that some genetic variation still exists within populations. However, significant amounts of variation exist between populations, perhaps reflecting population differentiation by drift. This partitioning of genetic diversity indicates that the level of inter?population gene exchange is extremely low. These findings are consistent with field observations of very limited seed production. The Chinese populations are similar to those of Northern Taiwan, while the Ryukyu populations fall within the range of variation of the north?central Taiwan populations. The Taiwanese populations are relatively variable and differentiation between north, east and south Taiwan is evident. • Conclusions The distribution of Titanotrichum seems to be consistent with a former land connection between China, Taiwan and the Ryukyu Islands at a glacial maximum during the Quaternary, followed by progressive fragmentation of the populations. North?central Taiwan is the centre of genetic diversity, possibly due to the proximity of the former land bridge between the regions, together with the variety of suitable habitats in north Taiwan. The significance of these findings for conservation is discussed. PMID:14707003

WANG, CHUN?NENG; MÖLLER, MICHAEL; CRONK, QUENTIN C. B.

2004-01-01

299

Trends in chlamydia and gonorrhea positivity among heterosexual men and men who have sex with men attending a large urban sexual health service in Australia, 2002-2009  

Microsoft Academic Search

Background  To determine whether chlamydia positivity among heterosexual men (MSW) and chlamydia and gonorrhea positivity among men who\\u000a have sex with men (MSM), are changing.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Computerized records for men attending a large sexual health clinic between 2002 and 2009 were analyzed. Chlamydia and gonorrhea\\u000a positivity were calculated and logistic regression used to assess changes over time.\\u000a \\u000a \\u000a \\u000a \\u000a Results  17769 MSW and 8328 MSM

Lenka A Vodstrcil; Christopher K Fairley; Glenda Fehler; David Leslie; Jennifer Walker; Catriona S Bradshaw; Jane S Hocking

2011-01-01

300

Phylogeography of competing sexual and parthenogenetic forms of a freshwater flatworm: patterns and explanations  

PubMed Central

Background Models of the maintenance of sex predict that one reproductive strategy, sexual or parthenogenetic, should outcompete the other. Distribution patterns may reflect the outcome of this competition as well as the effect of chance and historical events. We review the distribution data of sexual and parthenogenetic biotypes of the planarian Schmidtea polychroa. Results S. polychroa lives in allopatry or sympatry across Europe except for Central and North-Western Europe, where sexual individuals have never been reported. A phylogenetic relationship between 36 populations based on a 385 bp fragment of the mitochondrial cytochrome oxidase I gene revealed that haplotypes were often similar over large geographic distances. In North Italian lakes, however, diversity was extreme, with sequence differences of up to 5% within the same lake in both sexuals and parthenogens. Mixed populations showed "endemic" parthenogenetic lineages that presumably originated from coexisting sexuals, and distantly related ones that probably result from colonization by parthenogens independent from sexuals. Conclusions Parthenogens originated repeatedly from sexuals, mainly in Italy, but the same may apply to other Mediterranean regions (Spain, Greece). The degree of divergence between populations suggests that S. polychroa survived the ice ages in separate ice-free areas in Central, Eastern and Southern Europe and re-colonised Europe after the retreat of the major glaciers. Combining these results with those based on nuclear markers, the data suggest that repeated hybridisation between sexuals and parthenogenetic lineages in mixed populations maintains high levels of genetic diversity in parthenogens. This can explain why parthenogens persist in populations that were originally sexual. Exclusive parthenogenesis in central and western populations suggests better colonisation capacity, possibly because of inbreeding costs as well as hybridisation of sexuals with parthenogens. PMID:14622447

Pongratz, Norbert; Storhas, Martin; Carranza, Salvador; Michiels, Nicolaas K

2003-01-01

301

Nonprobability Web Surveys to Measure Sexual Behaviors and Attitudes in the General Population: A Comparison With a Probability Sample Interview Survey  

PubMed Central

Background Nonprobability Web surveys using volunteer panels can provide a relatively cheap and quick alternative to traditional health and epidemiological surveys. However, concerns have been raised about their representativeness. Objective The aim was to compare results from different Web panels with a population-based probability sample survey (n=8969 aged 18-44 years) that used computer-assisted self-interview (CASI) for sensitive behaviors, the third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3). Methods Natsal-3 questions were included on 4 nonprobability Web panel surveys (n=2000 to 2099), 2 using basic quotas based on age and sex, and 2 using modified quotas based on additional variables related to key estimates. Results for sociodemographic characteristics were compared with external benchmarks and for sexual behaviors and opinions with Natsal-3. Odds ratios (ORs) were used to express differences between the benchmark data and each survey for each variable of interest. A summary measure of survey performance was the average absolute OR across variables. Another summary measure was the number of key estimates for which the survey differed significantly (at the 5% level) from the benchmarks. Results For sociodemographic variables, the Web surveys were less representative of the general population than Natsal-3. For example, for men, the average absolute OR for Natsal-3 was 1.14, whereas for the Web surveys the average absolute ORs ranged from 1.86 to 2.30. For all Web surveys, approximately two-thirds of the key estimates of sexual behaviors were different from Natsal-3 and the average absolute ORs ranged from 1.32 to 1.98. Differences were appreciable even for questions asked by CASI in Natsal-3. No single Web survey performed consistently better than any other did. Modified quotas slightly improved results for men, but not for women. Conclusions Consistent with studies from other countries on less sensitive topics, volunteer Web panels provided appreciably biased estimates. The differences seen with Natsal-3 CASI questions, where mode effects may be similar, suggest a selection bias in the Web surveys. The use of more complex quotas may lead to some improvement, but many estimates are still likely to differ. Volunteer Web panels are not recommended if accurate prevalence estimates for the general population are a key objective. PMID:25488851

Burkill, Sarah; Couper, Mick P; Conrad, Frederick; Clifton, Soazig; Tanton, Clare; Phelps, Andrew; Datta, Jessica; Mercer, Catherine H; Sonnenberg, Pam; Prah, Philip; Mitchell, Kirstin R; Wellings, Kaye; Johnson, Anne M; Copas, Andrew J

2014-01-01

302

RESOURCES FOR VICTIMS OF SEXUAL ASSAULT Bronx District Attorney's Office  

E-print Network

Populations served: Survivors of rape / sexual assault, child sexual abuse, sexual harassment, incest and adults sexually abused as children within Queens County including: all ages. females. nonRESOURCES FOR VICTIMS OF SEXUAL ASSAULT 1 THE BRONX Bronx District Attorney's Office Crime Victims

Rosen, Jay

303

Hospitalization for lifestyle related diseases in long haul drivers compared with other truck drivers and the working population at large  

Microsoft Academic Search

Personal lifestyle and working conditions are closely linked for long haul truck drivers. We compare lifestyle related diseases in long haul drivers with other drivers of goods and the working population at large. Standardized hospital treatment ratios (SHR) for lifestyle related diseases were compared for long haul truck drivers and other truck drivers to the working population at large. The

Søren Dahl; Linda Kaerlev; Anker Jensen; Finn T; Harald Hannerz; Sabro Nielsen

2009-01-01

304

Correlates of Sexual Abuse and Smoking among French Adults  

ERIC Educational Resources Information Center

Objective: The goal of this study was to examine the association between sexual abuse (SA) and initiation, cessation, and current cigarette smoking among a large representative adult population in France. Method: A random sample size of 12,256 adults (18-75 years of age) was interviewed by telephone concerning demographic variables, health…

King, Gary; Guilbert, Philippe; Ward, D. Gant; Arwidson, Pierre; Noubary, Farzad

2006-01-01

305

Sexual harassment of university faculty by colleagues and students  

Microsoft Academic Search

The focus of this research was on faculty members as victims of sexual harassment by colleagues (peer harassment) and students (contrapower harassment). A self-administered, mailed questionnaire was sent to a probability sample of faculty at a large, public Midwestern university and to the whole population of faculty at a small, public institution in the Western Mountain region. Several hypotheses were

Kathleen McKinney

1990-01-01

306

Sexual Harassment, Sexual Coercion, and HIV Risk Among U.S. Adults 18-49 Years  

Microsoft Academic Search

Sexual harassment and sexual coercion have received considerable public attention. However, the extent of these problems nationally and the breadth of their health consequences are not fully understood. We estimated the national prevalence of sexual harassment and sexual coercion, and examined their relationship to HIV risk in the general U.S. population. Data came from a 1992 telephone survey of a

Kyung-Hee Choi; Diane Binson; Melissa Adelson; Joseph A. Catania

1998-01-01

307

Influence of study population on the identification of risk factors for sexually transmitted diseases using a case-control design: the example of gonorrhea.  

PubMed

The population prevalence of many sexually transmitted diseases (STDs) is low. Thus, most epidemiologic studies of STDs are conducted among STD clinic populations to maximize efficiency. However, STD clinic patients have unique sociobehavioral characteristics. To examine the potential effect of study population on identification of risk factors, the authors compared 1) STD clinic patients with a random digit dialing telephone sample, 2) general population cases with random digit dialing controls, and 3) STD clinic cases with STD clinic controls (Seattle, Washington, 1992-1995). Risk factors for gonorrhea identified among STD clinic patients formed a subset of those identified in the general population. In both populations, risk decreased with age (odds ratio for the general population (OR(GP)) = 0.4, 95% confidence interval (CI): 0.22, 0.59; odds ratio for the clinic population (OR(clinic)) = 0.5, 95% CI: 0.30, 0.81) and was increased among Blacks (OR(GP) = 15.5, 95% CI: 4.93, 49.0; OR(clinic) = 10.5, 95% CI: 4.51, 24.68) and persons whose partner had been jailed (OR(GP) = 5.4, 95% CI: 2.07, 13.9; OR(clinic )= 3.1, 95% CI: 1.32, 7.30). Additional factors associated with gonorrhea in the general population included secondary education (OR = 0.3, 95% CI: 0.11, 0.70), anal intercourse (OR = 10.5, 95% CI: 2.01, 54.7, STD history (OR = 5.9, 95% CI: 1.76, 19.5), meeting partners in structured settings (OR = 0.2, 95% CI: 0.09, 0.50), no condom use (OR = 3.2, 95% CI: 1.30, 7.89), and divorce (OR = 3.6, 95% CI: 1.07, 11.9). Risk factors identified in STD clinics will probably be confirmed in a general population sample, despite overcontrolling for shared behaviors; however, factors associated with both disease and STD clinic attendance may be missed. PMID:15286025

Manhart, Lisa E; Aral, Sevgi O; Holmes, King K; Critchlow, Cathy W; Hughes, James P; Whittington, William L H; Foxman, Betsy

2004-08-15

308

Genetic segregation and the maintenance of sexual reproduction  

Microsoft Academic Search

SEXUAL reproduction confronts evolutionary biology with a paradox: other things being equal, an asexual (all-female) population will have twice the reproductive potential of a competing sexual population and therefore should rapidly drive the sexual population to extinction1,2. Thus, the persistence of sexual reproduction in most life forms implies a compensatory advantage to sexual reproduction. Work on this problem has emphasized

Mark Kirkpatrick; Cheryl D. Jenkins

1989-01-01

309

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

310

Self-Reported Sexual Functioning Concerns among Undergraduate Students  

ERIC Educational Resources Information Center

Researchers who have studied sexual functioning concerns do not often focus their research on undergraduate populations, perhaps due to perceptions of universal sexual health among this population. The current study examined prevalence and type of sexual functioning concerns in a sample of 347 male and female undergraduate students. Sexual

Tambling, Rachel B.; Reckert, Ashley

2014-01-01

311

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

312

Behavioral Convergence: Implications for Mathematical Models of Sexually Transmitted Infection Transmission  

PubMed Central

Recent trends in the behaviors of some groups with high sexual activity and of the general population in some countries suggest that sexual behavior profiles of high and low sexual activity categories may be converging and may call into question the assumptions around sexual mixing that are built into theoretical models of sexually transmitted infections (STIs)/human immunodeficiency virus (HIV) transmission dynamics. One category of high sexual activity, sex work, has been undergoing modification in many societies, becoming more acceptable, more dispersed, and larger in volume in some societies and shrinking in others. Concurrent with changes in the characteristics of sex work, the accumulating data on the sexual behaviors of the general population suggest a shift toward those of sex workers, including large numbers of sex partners and short-duration partnerships. The closing of the gap between behaviors associated with high and low sexual activity may have important implications for theories of sexual structure and models of transmission dynamics for STIs, including HIV infection. PMID:25381381

Aral, Sevgi O.; Ward, Helen

2014-01-01

313

Behavioral convergence: implications for mathematical models of sexually transmitted infection transmission.  

PubMed

Recent trends in the behaviors of some groups with high sexual activity and of the general population in some countries suggest that sexual behavior profiles of high and low sexual activity categories may be converging and may call into question the assumptions around sexual mixing that are built into theoretical models of sexually transmitted infections (STIs)/human immunodeficiency virus (HIV) transmission dynamics. One category of high sexual activity, sex work, has been undergoing modification in many societies, becoming more acceptable, more dispersed, and larger in volume in some societies and shrinking in others. Concurrent with changes in the characteristics of sex work, the accumulating data on the sexual behaviors of the general population suggest a shift toward those of sex workers, including large numbers of sex partners and short-duration partnerships. The closing of the gap between behaviors associated with high and low sexual activity may have important implications for theories of sexual structure and models of transmission dynamics for STIs, including HIV infection. PMID:25381381

Aral, Sevgi O; Ward, Helen

2014-12-01

314

Evolutionary potential of a large marine vertebrate: quantitative genetic parameters in a wild population.  

PubMed

Estimating quantitative genetic parameters ideally takes place in natural populations, but relatively few studies have overcome the inherent logistical difficulties. For this reason, no estimates currently exist for the genetic basis of life-history traits in natural populations of large marine vertebrates. And yet such estimates are likely to be important given the exposure of this taxon to changing selection pressures, and the relevance of life-history traits to population productivity. We report such estimates from a long-term (1995-2007) study of lemon sharks (Negaprion brevirostris) conducted at Bimini, Bahamas. We obtained these estimates by genetically reconstructing a population pedigree (117 dams, 487 sires, and 1351 offspring) and then using an "animal model" approach to estimate quantitative genetic parameters. We find significant additive genetic (co)variance, and hence moderate heritability, for juvenile length and mass. We also find substantial maternal effects for these traits at age-0, but not age-1, confirming that genotype-phenotype interactions between mother and offspring are strongest at birth; although these effects could not be parsed into their genetic and nongenetic components. Our results suggest that human-imposed selection pressures (e.g., size-selective harvesting) might impose noteworthy evolutionary change even in large marine vertebrates. We therefore use our findings to explain how maternal effects may sometimes promote maladaptive juvenile traits, and how lemon sharks at different nursery sites may show "constrained local adaptation." We also show how single-generation pedigrees, and even simple marker-based regression methods, can provide accurate estimates of quantitative genetic parameters in at least some natural systems. PMID:19236474

Dibattista, Joseph D; Feldheim, Kevin A; Garant, Dany; Gruber, Samuel H; Hendry, Andrew P

2009-04-01

315

Evaluation of record linkage between a large healthcare provider and the Utah Population Database  

PubMed Central

Objective Electronically linked datasets have become an important part of clinical research. Information from multiple sources can be used to identify comorbid conditions and patient outcomes, measure use of healthcare services, and enrich demographic and clinical variables of interest. Innovative approaches for creating research infrastructure beyond a traditional data system are necessary. Materials and methods Records from a large healthcare system's enterprise data warehouse (EDW) were linked to a statewide population database, and a master subject index was created. The authors evaluate the linkage, along with the impact of missing information in EDW records and the coverage of the population database. The makeup of the EDW and population database provides a subset of cancer records that exist in both resources, which allows a cancer-specific evaluation of the linkage. Results About 3.4 million records (60.8%) in the EDW were linked to the population database with a minimum accuracy of 96.3%. It was estimated that approximately 24.8% of target records were absent from the population database, which enabled the effect of the amount and type of information missing from a record on the linkage to be estimated. However, 99% of the records from the oncology data mart linked; they had fewer missing fields and this correlated positively with the number of patient visits. Discussion and conclusion A general-purpose research infrastructure was created which allows disease-specific cohorts to be identified. The usefulness of creating an index between institutions is that it allows each institution to maintain control and confidentiality of their own information. PMID:21926112

DuVall, Scott L; Fraser, Alison M; Rowe, Kerry; Thomas, Alun

2011-01-01

316

Validation of Screening Questions for Limited Health Literacy in a Large VA Outpatient Population  

Microsoft Academic Search

Objectives  Previous studies have shown that a single question may identify individuals with inadequate health literacy. We evaluated\\u000a and compared the performance of 3 health literacy screening questions for detecting patients with inadequate or marginal health\\u000a literacy in a large VA population.\\u000a \\u000a \\u000a \\u000a Methods  We conducted in-person interviews among a random sample of patients from 4 VA medical centers that included 3 health

Lisa D. Chew; Joan M. Griffin; Melissa R. Partin; Siamak Noorbaloochi; Joseph P. Grill; Annamay Snyder; Katharine A. Bradley; Sean M. Nugent; Alisha D. Baines; Michelle VanRyn

2008-01-01

317

Poppr 1.0.5: An R package for genetic analysis of populations with mixed (clonal/sexual) reproduction  

E-print Network

of population genetic data enabling focus on data analysis and interpretation. While there are a plethora . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.4 Get out of my dreams and into my R {importing data into poppr} . . . . . . . . . . . . . . . 7

Grünwald, Niklaus J.

318

Large Magellanic Cloud Planetary Nebula Morphology: Probing Stellar Populations and Evolution.  

PubMed

Planetary nebulae (PNe) in the Large Magellanic Cloud (LMC) offer the unique opportunity to study both the population and evolution of low- and intermediate-mass stars, by means of the morphological type of the nebula. Using observations from our LMC PN morphological survey, and including images available in the Hubble Space Telescope Data Archive and published chemical abundances, we find that asymmetry in PNe is strongly correlated with a younger stellar population, as indicated by the abundance of elements that are unaltered by stellar evolution (Ne, Ar, and S). While similar results have been obtained for Galactic PNe, this is the first demonstration of the relationship for extragalactic PNe. We also examine the relation between morphology and abundance of the products of stellar evolution. We found that asymmetric PNe have higher nitrogen and lower carbon abundances than symmetric PNe. Our two main results are broadly consistent with the predictions of stellar evolution if the progenitors of asymmetric PNe have on average larger masses than the progenitors of symmetric PNe. The results bear on the question of formation mechanisms for asymmetric PNe-specifically, that the genesis of PNe structure should relate strongly to the population type, and by inference the mass, of the progenitor star and less strongly on whether the central star is a member of a close binary system. PMID:10813674

Stanghellini; Shaw; Balick; Blades

2000-05-10

319

Voluntary rewards mediate the evolution of pool punishment for maintaining public goods in large populations  

E-print Network

Punishment is a popular tool when governing commons in situations where free riders would otherwise take over. It is well known that sanctioning systems, such as the police and courts, are costly and thus can suffer from those who free ride on other's efforts to maintain the sanctioning systems (second-order free riders). Previous game-theory studies showed that if populations are very large, pool punishment rarely emerges in public good games, even when participation is optional, because of second-order free riders. Here we show that a matching fund for rewarding cooperation leads to the emergence of pool punishment, despite the presence of second-order free riders. We demonstrate that reward funds can pave the way for a transition from a population of free riders to a population of pool punishers. A key factor in promoting the transition is also to reward those who contribute to pool punishment, yet not abstaining from participation. Reward funds eventually vanish in raising pool punishment, which is sustai...

Sasaki, Tatsuya; Chen, Xiaojie

2015-01-01

320

Voluntary rewards mediate the evolution of pool punishment for maintaining public goods in large populations.  

PubMed

Punishment is a popular tool when governing commons in situations where free riders would otherwise take over. It is well known that sanctioning systems, such as the police and courts, are costly and thus can suffer from those who free ride on other's efforts to maintain the sanctioning systems (second-order free riders). Previous game-theory studies showed that if populations are very large, pool punishment rarely emerges in public good games, even when participation is optional, because of second-order free riders. Here we show that a matching fund for rewarding cooperation leads to the emergence of pool punishment, despite the presence of second-order free riders. We demonstrate that reward funds can pave the way for a transition from a population of free riders to a population of pool punishers. A key factor in promoting the transition is also to reward those who contribute to pool punishment, yet not abstaining from participation. Reward funds eventually vanish in raising pool punishment, which is sustainable by punishing the second-order free riders. This suggests that considering the interdependence of reward and punishment may help to better understand the origins and transitions of social norms and institutions. PMID:25753335

Sasaki, Tatsuya; Uchida, Satoshi; Chen, Xiaojie

2015-01-01

321

Voluntary rewards mediate the evolution of pool punishment for maintaining public goods in large populations  

NASA Astrophysics Data System (ADS)

Punishment is a popular tool when governing commons in situations where free riders would otherwise take over. It is well known that sanctioning systems, such as the police and courts, are costly and thus can suffer from those who free ride on other's efforts to maintain the sanctioning systems (second-order free riders). Previous game-theory studies showed that if populations are very large, pool punishment rarely emerges in public good games, even when participation is optional, because of second-order free riders. Here we show that a matching fund for rewarding cooperation leads to the emergence of pool punishment, despite the presence of second-order free riders. We demonstrate that reward funds can pave the way for a transition from a population of free riders to a population of pool punishers. A key factor in promoting the transition is also to reward those who contribute to pool punishment, yet not abstaining from participation. Reward funds eventually vanish in raising pool punishment, which is sustainable by punishing the second-order free riders. This suggests that considering the interdependence of reward and punishment may help to better understand the origins and transitions of social norms and institutions.

Sasaki, Tatsuya; Uchida, Satoshi; Chen, Xiaojie

2015-03-01

322

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

323

Gambling behavior and problem gambling reflecting social transition and traumatic childhood events among Greenland Inuit: a cross-sectional study in a large indigenous population undergoing rapid change.  

PubMed

An increase in social pathologies is a key feature in indigenous populations undergoing transition. The Greenland Inuit are a large indigenous population constituting a majority in their own country, which makes it possible to investigate differences within the population. This led us to study gambling behavior and problem gambling among Greenland Inuit in relation to the ongoing social transition and traumatic events during childhood. A large representative cross-sectional study was conducted among Greenland Inuit (n = 2,189). Data was collected among adults (18+) in 9 towns and 13 villages in Greenland from 2005 to 2010. Problem gambling, gambling behavior and traumatic childhood events were measured through a self-administered questionnaire. The lie/bet screen was used to identify past year and lifetime problem gambling. Social transition was measured as place of residence and a combination of residence, education and occupation. The lifetime prevalence of problem gambling was 16 % among men and 10 % among women (p < 0.0001); and higher in towns (19 %) compared to the capital of Nuuk (11 %) and in villages (12 %) (men only, p = 0.020). Lifetime problem gambling was associated with social transition (p = 0.023), alcohol problems in childhood home (p = 0.001/p = 0.002) and sexual abuse in childhood (women only, p = 0.030). A comparably high prevalence of lifetime problem gambling among Greenland Inuit adds problem gambling to the list of social pathologies in Greenland. A significant association between lifetime problem gambling, social transition and traumatic childhood events suggests people caught between tradition and modern ways of life are more vulnerable to gambling problems. PMID:23065180

Larsen, Christina Viskum Lytken; Curtis, Tine; Bjerregaard, Peter

2013-12-01

324

[Female sexual function and chronic disease].  

PubMed

Female sexual dysfunction (FSD) is a multifactorial set of conditions associated with multiple anatomical, physiological, biological, medical and psychological factors that can have major impact on self-esteem, quality of life, mood and relationships. Studies indicate that FSD is commonly seen in women who report a low level of satisfaction with partner relationship and in women with male partners who have erectile dysfunction. This complexity of FSD is augmented by the presence of chronic disease. Negative sexual effects are widely reported in studies of women with chronic diseases (such as metabolic syndrome, diabetes mellitus, chronic kidney disease, cancer, spinal cord injury, lupus, rheumatic diseases, Parkinson's disease, fibromyalgia and chronic pain) as compared to a general healthy female population. Physical problems, emotional problems and partnership difficulties arising from disease-related stress contribute to less active and less enjoyable sex life. Chronic pain, fatigue, low self-esteem as well as use of medications might reduce sexual function. These effects of chronic diseases on female sexual function still remain largely unstudied. The study by Manor and Zohar published in this issue of Harefuah draws our attention to the sexual dysfunction of women with breast cancer and examines their needs for information regarding their sexual function. In the absence of definite treatment evidence, psychological counseling, improved vaginal lubrication, low dose of hormonal therapy can be used to relieve FSD. Physicians must consider integrating diagnosis of their female patients' sexual needs and dysfunction, especially women with chronic diseases. Patients' education and counseling may contribute to a better quality of life in spite of their chronic disease. PMID:16509415

Bronner, Gila

2006-02-01

325

Characterization of mitochondrial haplogroups in a large population-based sample from the United States.  

PubMed

Mitochondrial DNA (mtDNA) haplogroups are valuable for investigations in forensic science, molecular anthropology, and human genetics. In this study, we developed a custom panel of 61 mtDNA markers for high-throughput classification of European, African, and Native American/Asian mitochondrial haplogroup lineages. Using these mtDNA markers, we constructed a mitochondrial haplogroup classification tree and classified 18,832 participants from the National Health and Nutrition Examination Surveys (NHANES). To our knowledge, this is the largest study to date characterizing mitochondrial haplogroups in a population-based sample from the United States, and the first study characterizing mitochondrial haplogroup distributions in self-identified Mexican Americans separately from Hispanic Americans of other descent. We observed clear differences in the distribution of maternal genetic ancestry consistent with proposed admixture models for these subpopulations, underscoring the genetic heterogeneity of the United States Hispanic population. The mitochondrial haplogroup distributions in the other self-identified racial/ethnic groups within NHANES were largely comparable to previous studies. Mitochondrial haplogroup classification was highly concordant with self-identified race/ethnicity (SIRE) in non-Hispanic whites (94.8 %), but was considerably lower in admixed populations including non-Hispanic blacks (88.3 %), Mexican Americans (81.8 %), and other Hispanics (61.6 %), suggesting SIRE does not accurately reflect maternal genetic ancestry, particularly in populations with greater proportions of admixture. Thus, it is important to consider inconsistencies between SIRE and genetic ancestry when performing genetic association studies. The mitochondrial haplogroup data that we have generated, coupled with the epidemiologic variables in NHANES, is a valuable resource for future studies investigating the contribution of mtDNA variation to human health and disease. PMID:24488180

Mitchell, Sabrina L; Goodloe, Robert; Brown-Gentry, Kristin; Pendergrass, Sarah A; Murdock, Deborah G; Crawford, Dana C

2014-07-01

326

PADI4 genotype is not associated with rheumatoid arthritis in a large UK Caucasian population  

PubMed Central

Background Polymorphisms of the peptidylarginine deiminase type 4 (PADI4) gene confer susceptibility to rheumatoid arthritis (RA) in East Asian people. However, studies in European populations have produced conflicting results. This study explored the association of the PADI4 genotype with RA in a large UK Caucasian population. Methods The PADI4_94 (rs2240340) single nucleotide polymorphism (SNP) was directly genotyped in a cohort of unrelated UK Caucasian patients with RA (n=3732) and population controls (n=3039). Imputed data from the Wellcome Trust Case Control Consortium (WTCCC) was used to investigate the association of PADI4_94 with RA in an independent group of RA cases (n=1859) and controls (n=10 599). A further 56 SNPs spanning the PADI4 gene were investigated for association with RA using data from the WTCCC study. Results The PADI4_94 genotype was not associated with RA in either the present cohort or the WTCCC cohort. Combined analysis of all the cases of RA (n=5591) and controls (n=13 638) gave an overall OR of 1.01 (95% CI 0.96 to 1.05, p=0.72). No association with anti-CCP antibodies and no interaction with either shared epitope or PTPN22 was detected. No evidence for association with RA was identified for any of the PADI4 SNPs investigated. Meta-analysis of previously published studies and our data confirmed no significant association between the PADI4_94 genotype and RA in people of European descent (OR 1.06, 95% CI 0.99 to 1.13, p=0.12). Conclusion In the largest study performed to date, the PADI4 genotype was not a significant risk factor for RA in people of European ancestry, in contrast to Asian populations. PMID:19470526

Burr, Marian L; Naseem, Haris; Hinks, Anne; Eyre, Steve; Gibbons, Laura J; Bowes, John; Wilson, Anthony G; Maxwell, James; Morgan, Ann W; Emery, Paul; Steer, Sophia; Hocking, Lynne; Reid, David M; Wordsworth, Paul; Harrison, Pille; Thomson, Wendy; Worthington, Jane; Barton, Anne

2010-01-01

327

Canadian fishery closures provide a large-scale test of the impact of gillnet bycatch on seabird populations  

PubMed Central

In 1992, the eastern Canadian gillnet fisheries for northern cod and Atlantic salmon were largely closed. These large-scale fishery closures resulted in the removal of tens of thousands of gillnets known to inflict high levels of seabird mortality. We used this unprecedented opportunity to test the effects of gillnet removal on seabird populations. Consistent with predictions, we show that the breeding populations of divers (auks, gannets; susceptible to gillnet bycatch) have increased from pre-closure levels, whereas the populations of scavenging surface-feeders (gulls; low vulnerability to gillnet bycatch but susceptible to removal of fisheries discards) have decreased. Using the most complete series of seabird census data for the species most vulnerable to bycatch, we demonstrate a positive population response of common murres to reduction in gillnet fishing within its foraging range. These findings support the widespread but seldom documented contention that fisheries bycatch negatively impacts populations of non-target large vertebrates. PMID:23720519

Regular, Paul; Montevecchi, William; Hedd, April; Robertson, Gregory; Wilhelm, Sabina

2013-01-01

328

Assessment of Sexual Behavior, Sexual Attitudes, and Sexual Risk in Sweden (1989–2003)  

Microsoft Academic Search

To assess changes in sexual behavior, sexual attitudes, and sexual risk related to HIV, we conducted mailed questionnaire surveys in random samples of the Swedish general population in 1989, 1994, 1997, 2000, and 2003 (total N = 13,762). Each sample consisted of 4,000–6,000 subjects aged 16–44 years, stratified by age: 16–17, 18–19, 20–24, 25–34, and 35–44 years. The overall participation

Claes Herlitz; Kristina Ramstedt

2005-01-01

329

Adolescent Sexuality.  

ERIC Educational Resources Information Center

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

Sharpe, Thomasina H.

2003-01-01

330

Sexual Health  

MedlinePLUS

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

331

Potential role for the PDE5 inhibitor sildenafil in the treatment of female sexual dysfunction  

Microsoft Academic Search

\\u000a Although female sexual dysfunction has been recognized as a health problem that affects the well-being of a large population\\u000a of both pre-and post-menopausal women, organic underlying causes that could be susceptible to pharmacologic or surgical treatment\\u000a have only recently been considered [1]. In the last decade significant discoveries in the biochemistry, physiology and pharmacology of male sexual function have\\u000a led

Jennifer T. Anger; Jennifer R. Berman

332

Biases in internet sexual health samples: Comparison of an internet sexuality survey and a national sexual health survey in Sweden  

Microsoft Academic Search

The internet is becoming a favored technology for carrying out survey research, and particularly sexual health research. However, its utility is limited by unresolved sampling questions such as how biased internet samples may be. This paper addresses this issue through comparison of a ‘gold standard’ random selection population-based sexual survey (The Swedish Sexual Life Survey) with an internet-based survey in

Michael W. Ross; Sven-Axel Månsson; Kristian Daneback; Al Cooper; Ronny Tikkanen

2005-01-01

333

Sexual Intimacy After Sexual Assault or Sexual Abuse1  

E-print Network

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

Machel, Hans

334

A WASHINGTON PHOTOMETRIC SURVEY OF THE LARGE MAGELLANIC CLOUD FIELD STAR POPULATION  

SciTech Connect

We present photometry for an unprecedented database of some 5.5 million stars distributed throughout the Large Magellanic Cloud main body, from 21 fields covering a total area of 7.6 deg{sup 2}, obtained from Washington CT{sub 1} T{sub 2} CTIO 4 m MOSAIC data. Extensive artificial star tests over the whole mosaic image data set and the observed behavior of the photometric errors with magnitude demonstrate the accuracy of the morphology and clearly delineate the position of the main features in the color-magnitude diagrams (CMDs). The representative T{sub 1}(MS TO) mags are on average {approx}0.5 mag brighter than the T{sub 1} mags for the 100% completeness level of the respective field, allowing us to derive an accurate age estimate. We have analyzed the CMD Hess diagrams and used the peaks in star counts at the main sequence turnoff and red clump (RC) locations to age date the most dominant sub-population (or 'representative' population) in the stellar population mix. The metallicity of this representative population is estimated from the locus of the most populous red giant branch track. We use these results to derive age and metallicity estimates for all of our fields. The analyzed fields span age and metallicity ranges covering most of the galaxy's lifetime and chemical enrichment, i.e., ages and metallicities between {approx}1 and 13 Gyr and {approx}-0.2 and -1.2 dex, respectively. We show that the dispersions associated with the mean ages and metallicities represent in general a satisfactory estimate of the age/metallicity spread ({approx}1-3 Gyr/0.2-0.3 dex), although a few subfields have a slightly larger age/metallicity spread. Finally, we revisit the study of the vertical structure (VS) phenomenon, a striking feature composed of stars that extend from the bottom, bluest end of the RC to {approx}0.45 mag fainter. We confirm that the VS phenomenon is not clearly seen in most of the studied fields and suggest that its occurrence is linked to some other condition(s) in addition to the appropriate age, metallicity, and the necessary red giant star density.

Piatti, Andres E. [Instituto de Astronomia y Fisica del Espacio, CC 67, Suc. 28, 1428, Ciudad de Buenos Aires (Argentina); Geisler, Doug; Mateluna, Renee, E-mail: andres@iafe.uba.ar [Departamento de Astronomia, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)

2012-10-01

335

A Washington Photometric Survey of the Large Magellanic Cloud Field Star Population  

NASA Astrophysics Data System (ADS)

We present photometry for an unprecedented database of some 5.5 million stars distributed throughout the Large Magellanic Cloud main body, from 21 fields covering a total area of 7.6 deg2, obtained from Washington CT 1 T 2 CTIO 4 m MOSAIC data. Extensive artificial star tests over the whole mosaic image data set and the observed behavior of the photometric errors with magnitude demonstrate the accuracy of the morphology and clearly delineate the position of the main features in the color-magnitude diagrams (CMDs). The representative T 1(MS TO) mags are on average ~0.5 mag brighter than the T 1 mags for the 100% completeness level of the respective field, allowing us to derive an accurate age estimate. We have analyzed the CMD Hess diagrams and used the peaks in star counts at the main sequence turnoff and red clump (RC) locations to age date the most dominant sub-population (or "representative" population) in the stellar population mix. The metallicity of this representative population is estimated from the locus of the most populous red giant branch track. We use these results to derive age and metallicity estimates for all of our fields. The analyzed fields span age and metallicity ranges covering most of the galaxy's lifetime and chemical enrichment, i.e., ages and metallicities between ~1 and 13 Gyr and ~-0.2 and -1.2 dex, respectively. We show that the dispersions associated with the mean ages and metallicities represent in general a satisfactory estimate of the age/metallicity spread (~1-3 Gyr/0.2-0.3 dex), although a few subfields have a slightly larger age/metallicity spread. Finally, we revisit the study of the vertical structure (VS) phenomenon, a striking feature composed of stars that extend from the bottom, bluest end of the RC to ~0.45 mag fainter. We confirm that the VS phenomenon is not clearly seen in most of the studied fields and suggest that its occurrence is linked to some other condition(s) in addition to the appropriate age, metallicity, and the necessary red giant star density.

Piatti, Andrés E.; Geisler, Doug; Mateluna, Renee

2012-10-01

336

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

337

Sexuality and Affection among Elderly German Men and Women in Long-Term Relationships: Results of a Prospective Population-Based Study  

PubMed Central

Satisfaction with sexual activity i.e. sexual satisfaction and the importance of sexuality and affection were analysed using data from the German “Interdisciplinary Longitudinal Study of Adult Development” (ILSE). At three measurement points, 1993–1995, 1997–1998, and 2004–2006 i.e. subjects' ages of 63, 67, and 74 years, participants' reports about their affection and sexual activity were collected. The sample of completed records used for this study consisted of 194 urban non-institutionalised participants, 68% male, all living with partners. Median levels of sexual satisfaction were reported, fluctuating between the measurement points of ages 63 to 74. Between baseline, first and second follow-up no differences were found in levels of sexual satisfaction, though at measurement points age 63 and 67 women were more satisfied than men. When measured at age 74, affection was given a higher priority than sexual activity. Although men and women reported similar priorities, sexual activity and affection were more important for men than for women. Satisfaction within the relationship can be predicted by the importance of affection, but not by that of sexual activity. Our results confirm the thesis of the ‘second language of sexuality’: for humans in their later years affection seems to be more important than for younger individuals. PMID:25369193

Müller, Britta; Nienaber, Christoph A.; Reis, Olaf; Kropp, Peter; Meyer, Wolfgang

2014-01-01

338

The influence of population dynamics and environmental conditions on salmon re-colonization after large-scale distrubance  

NASA Astrophysics Data System (ADS)

The transition from dispersal into unoccupied habitat to the establishment of a self-sustaining new population depends on the dynamics of the source and recipient populations, and the environmental conditions that facilitate or hinder exchange and successful reproduction. We used population growth rate, inter-annual variability estimates, habitat condition and size, hydrologic data, and an estimated dispersal effect to determine when colonizing pink salmon (Oncorhynchus gorbuscha) populations became self-sustaining after a long-term migration blockage (Hell’s Gate) was mitigated in the Fraser River, British Columbia, Canada. We used pink salmon spawning data from 1947 to 1987 in 66 streams to define populations, population growth rates, and the level of dispersal to newly accessible habitats. We also quantified the distance from source populations, the amount of newly accessible habitat, and determined whether stream flow conditions impeded fish passage at Hell’s Gate. Population dynamics models fit to observed data indicated that the combination of an initially large source population in the Fraser River below Hell’s Gate, high intrinsic growth rates linked to favorable climate-driven conditions, a constant supply of dispersers, and large amounts of newly available habitat resulted in the development of self-sustaining pink salmon populations in the Fraser River upstream of the historic barrier. Self-sustaining populations were developed within years of barrier removal and have continued to help expand the overall population of Fraser River pink salmon. However, not all locations had the same productivity and the magnitude of exchange among them was partly mediated by river conditions that permit or impede passage. Both re-colonized abundance levels were reduced and population spatial structure shifted relative to historic population abundance and spatial structure estimates.

Pess, G. R.; Hilborn, R.; Kloehn, K.; Quinn, T.

2010-12-01

339

Mental health of victims of sexual violence in eastern Congo: associations with daily stressors, stigma, and labeling  

PubMed Central

Background The conflict-ridden context of eastern Congo has set the scene for grueling human rights violations, with sexual violence as one of the ‘weapons of war’. Currently, sexual violence continues, with a considerable increase in civilian perpetrators. However, little is known regarding the particular impact of different experiences of sexual violence on adolescents’ mental health. This study therefore investigates the impact of sexual violence on eastern Congolese adolescents’ mental health and its differing associations with daily stressors, stigma, and the labeling of sexual violence (as ‘rape’ or ‘non-consensual sexual experience’). Methods A cross-sectional, population-based survey design was implemented in 22 secondary schools, randomly selected from a stratified sample, in Bunia, eastern Congo, a region extensively affected by war. A total of 1,305 school-going adolescent girls aged 11 to 23 participated. Self-report measures of mental health symptoms, war-related traumatic events, experiences of sexual violence, daily stressors, and stigmatization were administered. Differences in sociodemographic characteristics, traumatic experiences and daily and social stressors between types of sexual violence (rape, non-consensual sexual violence, no sexual violence) were explored through statistical analysis. ANCOVA analyses investigated associations between those risk factors and adolescents’ mental health. Results More than one third of eastern Congolese adolescent girls reported experiences of sexual violence. Elevated levels of daily stressors, experiences of stigmatization, and stressful war-related events were found amongst girl victims of sexual violence, with the highest levels for girls who labeled the sexual violence as rape. Daily stressors, stigmatization, and war-related events showed a large impact on the girls’ mental health. Last, girls who labeled the sexual violence as non-consensual sexual experiences reported more post-traumatic hyper-arousal and intrusion symptoms compared to those labeling the sexual violence as rape. Conclusions These findings point to the important association between how war-affected adolescent girls label sexual violence (rape or non-consensual sexual experiences) and their mental health. This study also documents the large impact of sexual violence on other stressors (daily stressors, stigmatization, and stressful war events) and the impact of these stressors on girl victims’ mental health. It discusses important implications for addressing sexual violence and its consequences in war-affected contexts. PMID:25195041

2014-01-01

340

Subterranean phylogeography of freshwater crayfishes shows extensive gene flow and surprisingly large population sizes.  

PubMed

Subterranean animals are currently viewed as highly imperiled, precariously avoiding extinction in an extreme environment of darkness. This assumption is based on a hypothesis that the reduction in visual systems and morphology common in cave faunas reflects a genetic inability to adapt and persist coupled with the perception of a habitat that is limited, disconnected, and fragile. Accordingly, 95% of cave fauna in the United States are presumed endangered due to surface environmental degradation and limited geographic distributions. Our study explores the subterranean phylogeography of stygobitic crayfishes in the southeastern United States, a global hotspot of groundwater biodiversity, using extensive geographic sampling and molecular data. Despite their endangered status, our results show that subterranean crayfish species have attained moderate to high levels of genetic diversity over their evolutionary histories with large population sizes and extensive gene flow among karst systems. We then compare the subterranean population histories to those of common surface stream-dwelling crayfishes. Our results show recent drastic declines in genetic variability in the surface crayfish and suggest that these species also warrant conservation attention. PMID:16313591

Buhay, Jennifer E; Crandall, Keith A

2005-12-01

341

Circadian analysis of large human populations: Inferences from the power grid.  

PubMed

Few, if any studies have focused on the daily rhythmic nature of modern industrialized populations. The present study utilized real-time load data from the U.S. Pacific Northwest electrical power grid as a reflection of human operative household activity. This approach involved actigraphic analyses of continuously streaming internet data (provided in 5?min bins) from a human subject pool of approximately 43 million primarily residential users. Rhythm analyses reveal striking seasonal and intra-week differences in human activity patterns, largely devoid of manufacturing and automated load interference. Length of the diurnal activity period (alpha) is longer during the spring than the summer (16.64?h versus 15.98?h, respectively; p?large human populations. PMID:25286134

Stowie, Adam C; Amicarelli, Mario J; Crosier, Caitlin J; Mymko, Ryan; Glass, J David

2015-03-01

342

Male mating behavior and costs of sexual harassment for females in cavernicolous and extremophile populations of Atlantic mollies ( Poecilia mexicana )  

Microsoft Academic Search

Summary The Atlantic molly Poecilia mexicana inhabits a variety of different habitat types, some of which are characterized by physicochemical stressors, such as toxic hydrogen sulfide (H2S), or the fish occur in lightless subterranean (cave) habitats. Using five different populations from surface habitats with or without H2S, and from a sulfidic and a non-sulfidic cave, I asked how extreme environmental

Martin Plath; Maulbeerallee Potsdam

2008-01-01

343

Populations  

NSDL National Science Digital Library

This chapter introduces population as a group of the same kind of organisms in a given space at a given time. The activities in this section will provide students with the opportunity to define population, estimate populations in a community, and count and compare populations within a community. Students will gain the knowledge in describing plant and animal populations living in a community. They will also experiment with plant populations to control growth and development, not to mention discuss the effects of abiotic conditions on a community.

Janet R. Galle

2005-01-01

344

The sociobiology of sex: inclusive fitness consequences of inter-sexual interactions  

PubMed Central

The diversity of social interactions between sexual partners has long captivated biologists, and its evolution has been interpreted largely in terms of ‘direct fitness’ pay-offs to partners and their descendants. Inter-sexual interactions also have ‘indirect effects’ by affecting the fitness of relatives, with important consequences for inclusive fitness. However, inclusive fitness arguments have received limited consideration in this context, and definitions of ‘direct’ and ‘indirect’ fitness effects in this field are often inconsistent with those of inclusive fitness theory. Here, we use a sociobiology approach based on inclusive fitness theory to distinguish between direct and indirect fitness effects. We first consider direct effects: we review how competition leads to sexual conflict, and discuss the conditions under which repression of competition fosters sexual mutualism. We then clarify indirect effects, and show that greenbeard effects, kin recognition and population viscosity can all lead to episodes of indirect selection on sexual interactions creating potential for sexual altruism and spite. We argue that the integration of direct and indirect fitness effects within a sociobiology approach enables us to consider a more diverse spectrum of evolutionary outcomes of sexual interactions, and may help resolving current debates over sexual selection and sexual conflict. PMID:22777019

Pizzari, Tommaso; Gardner, Andy

2012-01-01

345

Workplace bullying and sleep disturbances: findings from a large scale cross-sectional survey in the French working population  

E-print Network

1 Workplace bullying and sleep disturbances: findings from a large scale cross-sectional survey between workplace bullying, and its characteristics, and sleep disturbances in a large sample of employees of the French working population. Design: Workplace bullying, evaluated using the validated instrument developed

Paris-Sud XI, Université de

346

New X-ray lights on the supernova remnant population of the Large Magellanic Cloud  

NASA Astrophysics Data System (ADS)

Supernova remnants (SNRs) mark the end point of stellar evolution. They return nucleosynthesis products to the interstellar medium (ISM), enriching and mixing it with freshly-produced heavy elements. Studying SNRs in general, and their X-ray emission in particular, is crucial to advance our understanding of many important astrophysical processes. With an XMM-Newton Very Large Programme (PI: F. Haberl), we conducted an X-ray survey of the Large Magellanic Cloud (LMC). As opposed to the Milky Way, the LMC offers an ideal target, at a well-constrained distance with small absorption column densities. Thus, X-ray properties of the evolved end of the SNR population of a galaxy can be studied. I will present the characteristics of the newly X-ray-discovered SNRs, with emphasis on the discovery of several iron-rich SNRs, which are the most evolved remnants of type Ia (i.e. thermonuclear) supernovae. I will take advantage of the high level of completeness of our sample of SNRs to i) present the X-ray luminosity function (XLF) of LMC SNRs, extended towards lower-luminosity objects, comparing it to the XLF of SNRs in other galaxies; and ii) compare the spatial distribution of SNRs and star formation histories in the LMC.

Maggi, P.; Haberl, F.; Sasaki, M.; Kavanagh, P.; Filipovi?, M.; Bozzetto, L.; Points, S.; Chu, Y.; Gruendl, R.; Dickel, J.

2014-07-01

347

Cognitive Group Counselling for Sexual Offenders  

Microsoft Academic Search

Cognitive group counselling was employed with two populations of sexual offenders against children, one in a psychiatric setting, the other in a correctional institution. Both groups were assessed pre- and post-treatment using a psychometric package, which included the Sexual Myths (SM) subscale of the Sexual Knowledge and Attitude Test (SKAT), the Abel Cognition Scales (child sexual abuse-COG-C; rape-COG-R), the Hostility

Robin J. Watson; Lana E. Stermac

1994-01-01

348

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

349

Sexual knowledge of Canadian adolescents after completion of high school sexual education requirements  

PubMed Central

BACKGROUND: Formal sexual education is a mandatory component of the high school curriculum in most Canadian provinces. The present study was a preliminary assessment of sexual knowledge among a sample of Ontario adolescents who had completed their high school sexual education requirements. METHODS: A questionnaire, testing understanding of the learning objectives of Ontario’s minimally required high school sexual education course, was distributed in a paediatric emergency department to 200 adolescent patients who had completed the course. RESULTS: Respondents demonstrated good understanding of pregnancy physiology and sexually transmitted infections, but poor understanding of concepts related to reproductive physiology, contraception, HIV/AIDS and sexual assault. Most respondents could not identify Canada’s age of sexual consent. CONCLUSIONS: Respondents demonstrated concerning gaps in sexual knowledge despite completion of their sexual education requirements. Further studies must determine whether a representative, population-based student sample would exhibit similar findings. Sexual education currently offered in Ontario may require investigation. PMID:24421660

Kumar, Maya M; Lim, Rodrick; Langford, Cindy; Seabrook, Jamie A; Speechley, Kathy N; Lynch, Timothy

2013-01-01

350

Potential environmental influences on variation in body size and sexual size dimorphism among Arizona populations of the western diamond-backed rattlesnake (Crotalus atrox)  

USGS Publications Warehouse

Differences in resource availability and quality along environmental gradients are important influences contributing to intraspecific variation in body size, which influences numerous life-history traits. Here, we examined variation in body size and sexual size dimorphism (SSD) in relation to temperature, seasonality, and precipitation among 10 populations located throughout Arizona of the western diamond-backed rattlesnake (Crotalus atrox). Specifically, in our analyses we addressed the following questions: (i) Are adult males larger in cooler, wetter areas? (ii) Does female body size respond differently to environmental variation? (iii) Is seasonality a better predictor of body size variation? (iv) Is SSD positively correlated with increased resources? We demonstrate that male and female C. atrox are larger in body size in cooler (i.e., lower average annual maximum, minimum, and mean temperature) and wetter areas (i.e., higher average annual precipitation, more variable precipitation, and available surface water). Although SSD in C. atrox appeared to be more pronounced in cooler, wetter areas, this relationship did not achieve statistical significance. ?? 2010 Elsevier Ltd.

Amarello, M.; Nowak, E.M.; Taylor, E.N.; Schuett, G.W.; Repp, R.A.; Rosen, P.C.; Hardy, D.L.

2010-01-01

351

Rate of Adaptation in Sexuals and Asexuals: A Solvable Model of the Fisher–Muller Effect  

PubMed Central

The adaptation of large asexual populations is hampered by the competition between independently arising beneficial mutations in different individuals, which is known as clonal interference. In classic work, Fisher and Muller proposed that recombination provides an evolutionary advantage in large populations by alleviating this competition. Based on recent progress in quantifying the speed of adaptation in asexual populations undergoing clonal interference, we present a detailed analysis of the Fisher–Muller mechanism for a model genome consisting of two loci with an infinite number of beneficial alleles each and multiplicative (nonepistatic) fitness effects. We solve the deterministic, infinite population dynamics exactly and show that, for a particular, natural mutation scheme, the speed of adaptation in sexuals is twice as large as in asexuals. This result is argued to hold for any nonzero value of the rate of recombination. Guided by the infinite population result and by previous work on asexual adaptation, we postulate an expression for the speed of adaptation in finite sexual populations that agrees with numerical simulations over a wide range of population sizes and recombination rates. The ratio of the sexual to asexual adaptation speed is a function of population size that increases in the clonal interference regime and approaches 2 for extremely large populations. The simulations also show that the imbalance between the numbers of accumulated mutations at the two loci is strongly suppressed even by a small amount of recombination. The generalization of the model to an arbitrary number L of loci is briefly discussed. If each offspring samples the alleles at each locus from the gene pool of the whole population rather than from two parents, the ratio of the sexual to asexual adaptation speed is approximately equal to L in large populations. A possible realization of this scenario is the reassortment of genetic material in RNA viruses with L genomic segments. PMID:23979572

Park, Su-Chan; Krug, Joachim

2013-01-01

352

Effects of atypical and typical antipsychotic treatments on sexual function in patients with schizophrenia: 12-month results from the Intercontinental Schizophrenia Outpatient Health Outcomes (IC-SOHO) study  

Microsoft Academic Search

Purpose. – Sexual dysfunction in patients with schizophrenia can reduce quality of life and treatment compliance. This report will compare the effects of selected atypical and typical antipsychotics on sexual function in a large, international population of outpatients with schizophrenia who were treated over 1 year.Subjects and methods. – Outpatients with schizophrenia, who initiated or changed antipsychotic treatment, and entered

Martin Dossenbach; Yulia Dyachkova; Sebnem Pirildar; Martin Anders; Afaf Khalil; Aleksander Araszkiewicz; Tamara Shakhnovich; Aly Akram; Jan Pecenak; Margaret McBride; Tamas Treuer

2006-01-01

353

Effects of a large northern European no-take zone on flatfish populations.  

PubMed

In March 2006, a 360?km² no-take zone (NTZ) was established north of Gotland in the central Baltic Sea, with the purpose to scientifically evaluate the effects of a fishing ban on flatfish populations. A monitoring programme was set up to study the populations in the NTZ and in a reference area east of Gotland where the fishing pressure was high. The programme included fishing with multimesh survey nets, modelling of potential larval export and estimation of fish consumption by large marine predators. Overall, the results showed a clear positive effect of the NTZ on turbot Scophthalmus maximus, with higher densities in the closed area compared with the fished area and also higher densities after closure compared with before. The NTZ also had older individuals and a more even sex ratio. This, in combination with a high potential for larval export from the NTZ to Gotland, shows that the marine reserve may be important for maintaining a viable S. maximus stock at Gotland. Also, for flounder Platichthys flesus, the densities were higher in the NTZ compared to the reference area and there was a net larval export to the fished area. For both species, density-dependent growth was evident, with a lower length at age in the closed area. Potential predation by grey seal Halichoerus grypus and great cormorant Phalacrocorax carbo sinesis on flatfishes, that could hamper the evaluation of the marine reserve, was also addressed. Taken together, the results show that there are clear benefits of the fishing ban for both flatfish species within the NTZ, while the net effects on fisheries are difficult to quantify. PMID:24090556

Florin, A-B; Bergström, U; Ustups, D; Lundström, K; Jonsson, P R

2013-10-01

354

Sex-typed role in male adolescent sexual abuse survivors  

Microsoft Academic Search

Confusion and conflicts regarding sexual identity have been identified by clinicians as sequelae of sexual abuse in male adolescents. The empirical evidence supporting this assertion is limited, however. The purpose of this study was to examine the relationship between sexual abuse of male adolescents and their sexual self-concept in comparison to other clinical and nonclinical adolescent populations. The Bem Sex-Role

Melissa Frey Richardson; William Meredith; Douglas A. Abbot

1993-01-01

355

Prevalence of Sexual Dysfunctions  

PubMed Central

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

Simons, Jeffrey; Carey, Michael P.

2008-01-01

356

Establishment of facultative sexuals  

NASA Astrophysics Data System (ADS)

The existence of sex is one of the major unsolved problems in biology. We use computer simulations to model conditions in which sex may first become established. We develop an individual-based population model and show that a hypothetical facultative sex gene can fix, provided that the initial cost is low. It is demonstrated that the equilibrium fitness in the population increases with increasing population size and decreasing mutation rate. The probability of the establishment of the sex gene is found not to be directly related to the fitness difference between the asexual and sexual populations. This change in fitness on changing the parameters of the model is investigated.

Paley, Chris J.; Taraskin, Sergei N.; Elliott, Stephen R.

2007-06-01

357

Randomized Controlled Trials of Individual?Level, Population?Level, and Multilevel Interventions for Preventing Sexually Transmitted Infections: What Has Worked?  

Microsoft Academic Search

Background. Previous reviews of interventions to prevent sexually transmitted infections (STIs) focused mostly on human immunodeficiency virus (HIV) infection. We reviewed trials of interventions to prevent sexual trans- mission of any STI, employing a multilevel perspective. Methods. We searched MEDLINE, the Cochrane Central Register of Controlled Trials, and recent unpublished presentations through 2003, to identify randomized controlled trials of preventive

2005-01-01

358

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

Microsoft Academic Search

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

P. V. Mladenov; R. H. Emson

1990-01-01

359

Large Herbivore Impacts on Demographic Characteristics and Population Dynamics of an Endangered Orchid (Spiranthes parksii Correll)  

E-print Network

Spiranthes Parksii Correll is an endangered orchid of Texas. Populations of S. parksii are threatened by habitat loss and degradation resulting from human population growth and attendant development and resource extraction. Conservation easements...

Wonkka, Carissa Lyn

2012-02-14

360

Populational equilibrium through exosome-mediated Wnt signaling in tumor progression of diffuse large B-cell lymphoma.  

PubMed

Tumors are composed of phenotypically heterogeneous cell populations. The nongenomic mechanisms underlying transitions and interactions between cell populations are largely unknown. Here, we show that diffuse large B-cell lymphomas possess a self-organized infrastructure comprising side population (SP) and non-SP cells, where transitions between clonogenic states are modulated by exosome-mediated Wnt signaling. DNA methylation modulated SP-non-SP transitions and was correlated with the reciprocal expressions of Wnt signaling pathway agonist Wnt3a in SP cells and the antagonist secreted frizzled-related protein 4 in non-SP cells. Lymphoma SP cells exhibited autonomous clonogenicity and exported Wnt3a via exosomes to neighboring cells, thus modulating population equilibrium in the tumor. PMID:24563408

Koch, Raphael; Demant, Martin; Aung, Thiha; Diering, Nina; Cicholas, Anna; Chapuy, Bjoern; Wenzel, Dirk; Lahmann, Marlen; Güntsch, Annemarie; Kiecke, Christina; Becker, Sabrina; Hupfeld, Timo; Venkataramani, Vivek; Ziepert, Marita; Opitz, Lennart; Klapper, Wolfram; Trümper, Lorenz; Wulf, Gerald G

2014-04-01

361

Large-scale mono-clonal structure in the north peripheral population of blue coral, Heliopora coerulea.  

PubMed

We examined the genotypic diversity of the large population of Heliopora coerulea, discovered recently in Ooura Bay, northern Okinawa Main Island Japan, together with another large population in Shiraho Reef, also in southwest Japan, using 9 polymorphic microsatellite markers. From each population, 40 samples were systematically collected along 2 transect lines with 4-m intervals. Surprisingly, all 40 samples from Ooura Bay were mono-genotypic, implying that the huge coral structure (30 m×80 m) originated from a single larva. Conversely, the 40 samples collected from the Shiraho Reef site all had different genotypes; measurements of genetic diversity, H(E) and H(O), were 0.075-0.975 and 0.064-0.655, respectively. At least four factors are considered to make such a huge H. coerulea population with a single genotype in Ooura Bay, (1) origin of single larva or fragment (2) a genetic bottleneck, (3) post settlement selection, and (4) frequent asexual propagation. PMID:22897960

Yasuda, Nina; Abe, Mariko; Takino, Tsutomu; Kimura, Megumi; Lian, Chunlian; Nagai, Satoshi; Nakano, Yoshikatsu; Nadaoka, Kazuo

2012-09-01

362

Genetics of single-cell protein abundance variation in large yeast populations  

NASA Astrophysics Data System (ADS)

Variation among individuals arises in part from differences in DNA sequences, but the genetic basis for variation in most traits, including common diseases, remains only partly understood. Many DNA variants influence phenotypes by altering the expression level of one or several genes. The effects of such variants can be detected as expression quantitative trait loci (eQTL). Traditional eQTL mapping requires large-scale genotype and gene expression data for each individual in the study sample, which limits sample sizes to hundreds of individuals in both humans and model organisms and reduces statistical power. Consequently, many eQTL are probably missed, especially those with smaller effects. Furthermore, most studies use messenger RNA rather than protein abundance as the measure of gene expression. Studies that have used mass-spectrometry proteomics reported unexpected differences between eQTL and protein QTL (pQTL) for the same genes, but these studies have been even more limited in scope. Here we introduce a powerful method for identifying genetic loci that influence protein expression in the yeast Saccharomyces cerevisiae. We measure single-cell protein abundance through the use of green fluorescent protein tags in very large populations of genetically variable cells, and use pooled sequencing to compare allele frequencies across the genome in thousands of individuals with high versus low protein abundance. We applied this method to 160 genes and detected many more loci per gene than previous studies. We also observed closer correspondence between loci that influence protein abundance and loci that influence mRNA abundance of a given gene. Most loci that we detected were clustered in `hotspots' that influence multiple proteins, and some hotspots were found to influence more than half of the proteins that we examined. The variants that underlie these hotspots have profound effects on the gene regulatory network and provide insights into genetic variation in cell physiology between yeast strains.

Albert, Frank W.; Treusch, Sebastian; Shockley, Arthur H.; Bloom, Joshua S.; Kruglyak, Leonid

2014-02-01

363

Sleep and use of electronic devices in adolescence: results from a large population-based study  

PubMed Central

Objectives Adolescents spend increasingly more time on electronic devices, and sleep deficiency rising in adolescents constitutes a major public health concern. The aim of the present study was to investigate daytime screen use and use of electronic devices before bedtime in relation to sleep. Design A large cross-sectional population-based survey study from 2012, the youth@hordaland study, in Hordaland County in Norway. Setting Cross-sectional general community-based study. Participants 9846 adolescents from three age cohorts aged 16–19. The main independent variables were type and frequency of electronic devices at bedtime and hours of screen-time during leisure time. Outcomes Sleep variables calculated based on self-report including bedtime, rise time, time in bed, sleep duration, sleep onset latency and wake after sleep onset. Results Adolescents spent a large amount of time during the day and at bedtime using electronic devices. Daytime and bedtime use of electronic devices were both related to sleep measures, with an increased risk of short sleep duration, long sleep onset latency and increased sleep deficiency. A dose–response relationship emerged between sleep duration and use of electronic devices, exemplified by the association between PC use and risk of less than 5?h of sleep (OR=2.70, 95% CI 2.14 to 3.39), and comparable lower odds for 7–8?h of sleep (OR=1.64, 95% CI 1.38 to 1.96). Conclusions Use of electronic devices is frequent in adolescence, during the day as well as at bedtime. The results demonstrate a negative relation between use of technology and sleep, suggesting that recommendations on healthy media use could include restrictions on electronic devices. PMID:25643702

Hysing, Mari; Pallesen, Ståle; Stormark, Kjell Morten; Jakobsen, Reidar; Lundervold, Astri J; Sivertsen, Børge

2015-01-01

364

Sexual Dimorphism  

E-print Network

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

Frayer, David W.; Wolpoff, Milford H.

1985-01-01

365

Intraocular surgery in a large diabetes patient population: risk factors and surgical results.  

PubMed

The prevalence of diabetes is on the increase in developed countries. Accordingly, the prevention and treatment of vision-threatening diabetic eye complications is assuming greater importance. The overall aim of this thesis is to analyse risk factors for intraocular surgery in a large diabetes population and to report surgical results. The specific objectives are to (1) estimate the incidence of diabetic vitrectomy and analyse risk factors (Study I), (2) report long-term results, prognostic factors and incidence of cataract surgery after diabetic vitrectomy (Study II), (3) report results and prognostic factors after cataract surgery in diabetes patients (Study III) and (4) analyse risk factors for diabetic papillopathy with emphasis on metabolic control variability (Study IV). All studies are based on a close-to-complete national surgery register and a large, closely followed diabetic retinopathy screening population. Study I (cohort study, 3980 type 1 diabetes patients) illustrates that diabetic vitrectomy is rarely required in a diabetes patient population with varying degrees of diabetic retinopathy. The risk of reaching diabetic vitrectomy increases fourfold with poor metabolic control, defined as glycosylated haemoglobin A1c > 75 mmol/mol (~9%), which points to good metabolic control as an important preventive measure. Study II (cohort study, 167 diabetes patients) shows that most diabetic vitrectomy patients stand to gain visual acuity ?0.3 after surgery. Visual acuity is stable after 1 year, and the stability is maintained through 10 years of follow-up. The use of silicone oil for endotamponade is a consistent long-term predictor of low vision after surgery. The risk of requiring cataract surgery after diabetic vitrectomy is substantial, and the risk increases if silicone oil is used. Study III (cohort study, 285 diabetes patients) shows, on the other hand, that diabetes patients can expect a significant improvement in visual acuity after cataract surgery, regardless of the degree of diabetic retinopathy. Poor preoperative visual acuity, a high degree of diabetic retinopathy and advanced age are predictors of a poor visual acuity after surgery. The risk of diabetic macular oedema after surgery is 4%. Finally, Study IV (case-control study, 2066 type 1 diabetes patients) demonstrates that diabetic papillopathy shares characteristics with diabetic retinopathy. The risk of experiencing diabetic papillopathy increases markedly with a drastic, recent reduction in glycosylated haemoglobin A1c and a small optic disc. This lends support to the theory that diabetic eye complications may occur in anatomically predisposed patients in response to metabolic control variability. Overall, results after intraocular surgery in diabetes patients are favourable. Surgery, however, is associated with costs to society, patient discomfort and risk of complications. This thesis provides an analysis of risk factors for intraocular surgery and identifies prognostic factors for visual acuity after surgery, which can be used for preventive purposes, surgical decision-making and patient counselling. PMID:24809766

Ostri, Christoffer

2014-05-01

366

A large outbreak of shigellosis commencing in an internally displaced population, Papua New Guinea, 2013  

PubMed Central

Objective The objective of this study was to investigate a large outbreak of shigellosis in Papua New Guinea that began in a camp for internally displaced persons before spreading throughout the general community. Methods Outbreak mitigation strategies were implemented in the affected area to curtail the spread of the disease. Data were collected from the surveillance system and analysed by time, place and person. Rectal swab samples were tested by standard culture methods and real-time polymerase chain reaction to determine the etiology of the outbreak. Results Laboratory analysis at two independent institutions established that the outbreak was caused by Shigella sp., with one strain further characterized as Shigella flexneri serotype 2. Approximately 1200 suspected cases of shigellosis were reported in a two-month period from two townships in Morobe Province, Papua New Guinea. The outbreak resulted in at least five deaths, all in young children. Discussion This outbreak of shigellosis highlights the threat of enteric diseases to vulnerable populations such as internally displaced persons in Papua New Guinea, as has been observed in other global settings. PMID:25648967

Benny, Edwin; Mesere, Kelly; Pavlin, Boris I; Yakam, Logan; Ford, Rebecca; Yoannes, Mition; Kisa, Debbie; Abdad, Mohammad Y; Menda, Lincoln; Greenhill, Andrew R

2014-01-01

367

A Deployable In Vivo EPR Tooth Dosimeter for Triage After a Radiation Event Involving Large Populations  

PubMed Central

In order to meet the potential need for emergency large-scale retrospective radiation biodosimetry following an accident or attack, we have developed instrumentation and methodology for in vivo electron paramagnetic resonance spectroscopy to quantify concentrations of radiation-induced radicals within intact teeth. This technique has several very desirable characteristics for triage, including independence from confounding biologic factors, a non-invasive measurement procedure, the capability to make measurements at any time after the event, suitability for use by non-expert operators at the site of an event, and the ability to provide immediate estimates of individual doses. Throughout development there has been a particular focus on the need for a deployable system, including instrumental requirements for transport and field use, the need for high throughput, and use by minimally trained operators. Numerous measurements have been performed using this system in clinical and other non-laboratory settings, including in vivo measurements with unexposed populations as well as patients undergoing radiation therapies. The collection and analyses of sets of three serially-acquired spectra with independent placements of the resonator, in a data collection process lasting approximately five minutes, provides dose estimates with standard errors of prediction of approximately 1 Gy. As an example, measurements were performed on incisor teeth of subjects who had either received no irradiation or 2 Gy total body irradiation for prior bone marrow transplantation; this exercise provided a direct and challenging test of our capability to identify subjects who would be in need of acute medical care. PMID:21966241

Williams, Benjamin B.; Dong, Ruhong; Flood, Ann Barry; Grinberg, Oleg; Kmiec, Maciej; Lesniewski, Piotr N.; Matthews, Thomas P.; Nicolalde, Roberto J.; Raynolds, Tim; Salikhov, Ildar K.; Swartz, Harold M.

2011-01-01

368

Marine population connectivity: reconciling large-scale dispersal and high self-retention.  

PubMed

Abstract Predicting connectivity patterns in systems with fluid transport requires descriptions of the spatial distribution of propagules. In contrast to research on terrestrial seed dispersal, where much attention has focused on localized physical factors affecting dispersal, studies of oceanic propagule dispersal have often emphasized the role of large-scale factors. We link these two perspectives by exploring how propagule dispersal in the ocean is influenced by the "coastal boundary layer" (CBL), a region of reduced velocities near the shoreline that might substantially modify local-scale dispersal. We used a simple simulation model to demonstrate that accounting for the CBL markedly alters transport distances, the widths of dispersal distributions, and the fraction of larvae retained near their sites of origin (self-retention). Median dispersal distances were up to 59% shorter in simulations with a CBL than in those without. Self-retention of larvae increased by up to 3 orders of magnitude in the presence of CBLs, but only minor changes arose in the long-distance tails of the distributions, resulting in asymmetric, non-Gaussian kernels analogous to those quantified for terrestrial seed dispersal. Because successfully settling larvae are commonly those that remain close to shore and interact with the CBL, ignoring this pervasive oceanographic feature will substantially alter predictions of population self-persistence, estimates of connectivity, and outcomes of metapopulation analyses. PMID:25616139

Nickols, Kerry J; White, J Wilson; Largier, John L; Gaylord, Brian

2015-02-01

369

Concurrence of multiple human papillomavirus infections in a large US population-based cohort.  

PubMed

We examined the concurrence of multiple human papillomavirus (HPV) infections in 47,617 women who underwent cervical screening in New Mexico between December 2007 and April 2009 using the LINEAR ARRAY HPV Genotyping Test (Roche Diagnostics, Indianapolis, Indiana), which detects 37 different types of HPV. Our primary goal was to examine the distributions of multiple HPV types with a special interest in negative interactions, which could signal the possibility of type replacement associated with a common niche if some HPV types were prevented by vaccination. Multiple infections were found to be more common than expected under independence, but this could largely be accounted for by a woman-specific latent heterogeneity parameter which was found to be dependent on age and cytological grade. While multiple infections were more common in young women and in those with abnormal cytology, greater heterogeneity was seen in older women and in those with normal cytology, possibly reflecting greater variability in exposure due to current or past HPV exposure or due to heterogeneity in related HPV reactivation or in immune responses to HPV infection or persistence. A negative interaction was found between HPV 16 and several other HPV types for women with abnormal cytology but not for those with normal cytology, suggesting that type replacement in women vaccinated against HPV 16 is unlikely to be an issue for the general population. PMID:25355446

Yang, Zihua; Cuzick, Jack; Hunt, William C; Wheeler, Cosette M

2014-12-01

370

Preferential enrichment of large-sized very low density lipoprotein populations with transferred cholesteryl esters  

SciTech Connect

The effect of lipid transfer proteins on the exchange and transfer of cholesteryl esters from rat plasma HDL2 to human very low (VLDL) and low density (LDL) lipoprotein populations was studied. The use of a combination of radiochemical and chemical methods allowed separate assessment of (/sup 3/H)cholesteryl ester exchange and of cholesteryl ester transfer. VLDL-I was the preferred acceptor for transferred cholesteryl esters, followed by VLDL-II and VLDL-III. LDL did not acquire cholesteryl esters. The contribution of exchange of (/sup 3/H)cholesteryl esters to total transfer was highest for LDL and decreased in reverse order along the VLDL density range. Inactivation of lecithin: cholesterol acyltransferase (LCAT) and heating the HDL2 for 60 min at 56 degrees C accelerated transfer and exchange of (/sup 3/H)cholesteryl esters. Addition of lipid transfer proteins increased cholesterol esterification in all systems. The data demonstrate that large-sized, triglyceride-rich VLDL particles are preferred acceptors for transferred cholesteryl esters. It is suggested that enrichment of very low density lipoproteins with cholesteryl esters reflects the triglyceride content of the particles.

Eisenberg, S.

1985-04-01

371

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

372

Bem Sex Role Inventory Undifferentiated Score: A Comparison of Sexual Dysfunction Patients with Sexual Offenders.  

ERIC Educational Resources Information Center

Examined Bem Sex Role undifferentiated scores on 93 male sex offenders as compared with 50 male sexually dysfunctional patients. Chi-square analyses revealed significant difference: offenders obtained undifferentiated scores more often than did sexual dysfunctional population. Concluded that Bem Sex Role Inventory is useful in identifying sexual

Dwyer, Margretta; And Others

1988-01-01

373

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

E-print Network

LETTER Operational sex ratio, sexual conflict and the intensity of sexual selection Patrick S.fitze@mncn.csic.es Abstract Modern sexual selection theory indicates that reproductive costs rather than the operational sex when adult sex ratios (ASR) are male- biased. We manipulated ASR in 12 experimental populations

Alvarez, Nadir

374

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

Microsoft Academic Search

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

Patrick S. Fitze; Jean-François Le Galliard

2008-01-01

375

Hybrid Zones and Sexual Selection 503 HYBRID ZONES AND SEXUAL SELECTION: INSIGHTS FROM  

E-print Network

Hybrid Zones and Sexual Selection 503 HYBRID ZONES AND SEXUAL SELECTION: INSIGHTS FROM THE AWASH BABOON HYBRID ZONE (Papio hamadryas anubis x P. h. hamadryas) Thore J. Bergman and Jacinta C. Beehner, have focused on the impact of sexual selection on populations of naturally occurring hybrid animals

376

Population.  

ERIC Educational Resources Information Center

In an effort to help meet the growing interest and concern about the problems created by the rapid growth of population, The International Planned Parenthood Federation has prepared this booklet with the aim of assisting the study of the history and future trends of population growth and its impact on individual and family welfare, national,…

International Planned Parenthood Federation, London (England).

377

Population Structure and Dispersal Patterns within and between Atlantic and Mediterranean Populations of a Large-Range Pelagic Seabird  

PubMed Central

Dispersal is critically linked to the demographic and evolutionary trajectories of populations, but in most seabird species it may be difficult to estimate. Using molecular tools, we explored population structure and the spatial dispersal pattern of a highly pelagic but philopatric seabird, the Cory's shearwater Calonectris diomedea. Microsatellite fragments were analysed from samples collected across almost the entire breeding range of the species. To help disentangle the taxonomic status of the two subspecies described, the Atlantic form C. d. borealis and the Mediterranean form C. d. diomedea, we analysed genetic divergence between subspecies and quantified both historical and recent migration rates between the Mediterranean and Atlantic basins. We also searched for evidence of isolation by distance (IBD) and addressed spatial patterns of gene flow. We found a low genetic structure in the Mediterranean basin. Conversely, strong genetic differentiation appeared in the Atlantic basin. Even if the species was mostly philopatric (97%), results suggest recent dispersal between basins, especially from the Atlantic to the Mediterranean (aprox. 10% of migrants/generation across the last two generations). Long-term gene flow analyses also suggested an historical exchange between basins (about 70 breeders/generation). Spatial analysis of genetic variation indicates that distance is not the main factor in shaping genetic structure in this species. Given our results we recommend gathering more data before concluded whether these taxa should be treated as two species or subspecies. PMID:23950986

Genovart, Meritxell; Thibault, Jean-Claude; Igual, José Manuel; Bauzà-Ribot, Maria del Mar; Rabouam, Corinne; Bretagnolle, Vincent

2013-01-01

378

The Effective Population Size of Malaria Mosquitoes: Large Impact of Vector Control  

PubMed Central

Malaria vectors in sub-Saharan Africa have proven themselves very difficult adversaries in the global struggle against malaria. Decades of anti-vector interventions have yielded mixed results—with successful reductions in transmission in some areas and limited impacts in others. These varying successes can be ascribed to a lack of universally effective vector control tools, as well as the development of insecticide resistance in mosquito populations. Understanding the impact of vector control on mosquito populations is crucial for planning new interventions and evaluating existing ones. However, estimates of population size changes in response to control efforts are often inaccurate because of limitations and biases in collection methods. Attempts to evaluate the impact of vector control on mosquito effective population size (Ne) have produced inconclusive results thus far. Therefore, we obtained data for 13–15 microsatellite markers for more than 1,500 mosquitoes representing multiple time points for seven populations of three important vector species—Anopheles gambiae, An. melas, and An. moucheti—in Equatorial Guinea. These populations were exposed to indoor residual spraying or long-lasting insecticidal nets in recent years. For comparison, we also analyzed data from two populations that have no history of organized vector control. We used Approximate Bayesian Computation to reconstruct their demographic history, allowing us to evaluate the impact of these interventions on the effective population size. In six of the seven study populations, vector control had a dramatic impact on the effective population size, reducing Ne between 55%–87%, the exception being a single An. melas population. In contrast, the two negative control populations did not experience a reduction in effective population size. This study is the first to conclusively link anti-vector intervention programs in Africa to sharply reduced effective population sizes of malaria vectors. PMID:23271973

Athrey, Giridhar; Hodges, Theresa K.; Reddy, Michael R.; Overgaard, Hans J.; Matias, Abrahan; Ridl, Frances C.; Kleinschmidt, Immo; Caccone, Adalgisa; Slotman, Michel A.

2012-01-01

379

Sexual dysfunction after renal replacement therapy  

Microsoft Academic Search

The existence of a sexual problem as the subjective evaluation of sexual function was assessed with a simple questionnaire. Those questioned were patients undergoing dialysis treatment (n = 400) or with a functioning renal transplant (RTx; n = 300) and both men and women in the general Dutch population (n = 591). In the Dutch control population, 8.7% of the

Willem L. Diemont; Peter A. Vruggink; Eric J. H. Meuleman; Wim H. Doesburg; Wim A. J. G. Lemmens; Jo H. M. Berden

2000-01-01

380

Large delay in flowering in continental versus coastal populations of a Mediterranean shrub, Globularia alypum.  

PubMed

Globularia alypum is a perennial shrub typical of western Mediterranean thermophilous shrublands. Nine populations of G. alypum located in different localities of Catalonia (NE Spain) were surveyed for flowering phenology. Flower-head buds were present in all the populations in July. Flowering time in the area spans from the late summer-early autumn to the next spring depending on the populations; there are two groups of populations, early and late flowering. Early populations grow mostly in coastal localities and flower from September to November, whereas late flowering populations grow in inland localities and flower from February to April. The flowering order of the populations correlated with minimum temperature of most months except the warmest ones, and correlated with maximum and mean temperatures of the coldest months. Correlations were similar when tested with annual climate. The flowering order also correlated with the thermic interval for most months except the coldest and with the index of continentality. Early populations alone did not present correlations with any variable, whereas late populations alone correlated similarly to all populations together. Flowering order did not correlate with precipitation. Late populations are proposed to be regulated by temperature according to our results whereas early populations could be regulated by timing in precipitation after summer drought, according to published results. We discuss the possibilities of the two flowering patterns, early and late, being due to phenotypic plasticity or to genetic adaptation to local climates. We also discuss the consequences at the plant and ecosystem level of climate warming causing shifts from late to early patterns, a possibility that is likely in the warmest of the late populations if flowering is modulated phenotypically. PMID:21476130

Estiarte, Marc; Puig, Gloria; Peñuelas, Josep

2011-11-01

381

Selective advantage for sexual reproduction  

NASA Astrophysics Data System (ADS)

We develop a simplified model for sexual replication within the quasispecies formalism. We assume that the genomes of the replicating organisms are two-chromosomed and diploid, and that the fitness is determined by the number of chromosomes that are identical to a given master sequence. We also assume that there is a cost to sexual replication, given by a characteristic time ?seek during which haploid cells seek out a mate with which to recombine. If the mating strategy is such that only viable haploids can mate, then when ?seek= 0 , it is possible to show that sexual replication will always outcompete asexual replication. However, as ?seek increases, sexual replication only becomes advantageous at progressively higher mutation rates. Once the time cost for sex reaches a critical threshold, the selective advantage for sexual replication disappears entirely. The results of this talk suggest that sexual replication is not advantageous in small populations per se, but rather in populations with low replication rates. In this regime, the cost for sex is sufficiently low that the selective advantage obtained through recombination leads to the dominance of the strategy. In fact, at a given replication rate and for a fixed environment volume, sexual replication is selected for in high populations because of the reduced time spent finding a reproductive partner.

Tannenbaum, Emmanuel

2006-03-01

382

Selective advantage for sexual reproduction  

NASA Astrophysics Data System (ADS)

This paper develops a simplified model for sexual reproduction within the quasispecies formalism. The model assumes a diploid genome consisting of two chromosomes, where the fitness is determined by the number of chromosomes that are identical to a given master sequence. We also assume that there is a cost to sexual reproduction, given by a characteristic time ?seek during which haploid cells seek out a mate with which to recombine. If the mating strategy is such that only viable haploids can mate, then when ?seek=0 , it is possible to show that sexual reproduction will always out compete asexual reproduction. However, as ?seek increases, sexual reproduction only becomes advantageous at progressively higher mutation rates. Once the time cost for sex reaches a critical threshold, the selective advantage for sexual reproduction disappears entirely. The results of this paper suggest that sexual reproduction is not advantageous in small populations per se, but rather in populations with low replication rates. In this regime, the cost for sex is sufficiently low that the selective advantage obtained through recombination leads to the dominance of the strategy. In fact, at a given replication rate and for a fixed environment volume, sexual reproduction is selected for in high populations because of the reduced time spent finding a reproductive partner.

Tannenbaum, Emmanuel

2006-06-01

383

Waterscape genetics of the yellow perch (Perca flavescens): patterns across large connected ecosystems and isolated relict populations.  

PubMed

Comparisons of a species' genetic diversity and divergence patterns across large connected populations vs. isolated relict areas provide important data for understanding potential response to global warming, habitat alterations and other perturbations. Aquatic taxa offer ideal case studies for interpreting these patterns, because their dispersal and gene flow often are constrained through narrow connectivity channels that have changed over geological time and/or from contemporary anthropogenic perturbations. Our research objective is to better understand the interplay between historic influences and modern-day factors (fishery exploitation, stocking supplementation and habitat loss) in shaping population genetic patterns of the yellow perch Perca flavescens (Percidae: Teleostei) across its native North American range. We employ a modified landscape genetics approach, analysing sequences from the entire mitochondrial DNA control region and 15 nuclear DNA microsatellite loci of 664 spawning adults from 24 populations. Results support that perch from primary glacial refugium areas (Missourian, Mississippian and Atlantic) founded contemporary northern populations. Genetic diversity today is highest in southern (never glaciated) populations and also is appreciable in northern areas that were founded from multiple refugia. Divergence is greater among isolated populations, both north and south; the southern Gulf Coast relict populations are the most divergent, reflecting their long history of isolation. Understanding the influence of past and current waterway connections on the genetic structure of yellow perch populations may help us to assess the roles of ongoing climate change and habitat disruptions towards conserving aquatic biodiversity. PMID:23078285

Sepulveda-Villet, Osvaldo J; Stepien, Carol A

2012-12-01

384

Evidence of large-scale source-sink dynamics and long-distance dispersal among Wood Thrush populations.  

PubMed

Source-sink dynamics are commonly thought to occur among Wood Thrush (Hylocichla mustelina) and other songbird populations, allowing for the persistence of populations with negative growth rates ("sinks") through immigration from populations with positive growth rates ("sources"). Knowledge of source-sink dynamics is important for management and conservation because the removal of source habitat should result in the extinction of dependent sinks. However, since research has focused on identifying individual sources/sink populations, not source-sink pairs, we cannot predict these effects or the scale over which they occur. We posit that, when dispersal occurs from a source to a sink year after year, there will be a one-year time-lagged correlation in abundance between the two populations. This should occur for populations separated by distances over which juveniles disperse. Using the North American Breeding Bird Survey data, we tested for such time-lagged correlations between paired Wood Thrush populations from 10 to 200 km apart. Populations were linked with a one-year time lag over distances from 60 to 80 km, indicating that dispersal and source-sink dynamics may occur over these long distances. There was also a declining trend in forest cover from sources to sinks. Conservation and management strategies should therefore be designed at large scales, with consideration for source-sink dynamics and forest cover. PMID:17249228

Tittler, Rebecca; Fahrig, Lenore; Villard, Marc-André

2006-12-01

385

Environmental stochasticity and population dynamics of large herbivores: a search for mechanisms  

Microsoft Academic Search

Recently, the results from several long-term individual-based population studies of ungulates have been published. One major conclusion is that the population dynamics of ungulates in predator-free environments is strongly influenced by a combination of stochastic variation in the environment, and population density. Both density dependence and environmental stochasticity operate through changes in life history traits, correlated with variation in body

Bernt-Erik Sæther

1997-01-01

386

Sexual Abuse  

MedlinePLUS

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

387

Sexual Sadism  

Microsoft Academic Search

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

Wolfgang Berner; Peter Berger; Andreas Hill

2003-01-01

388

Sexual selection  

Microsoft Academic Search

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

Malte Andersson; Yoh Iwasa

1996-01-01

389

Metallicity, distance, and distribution of populous clusters in the Large Magellanic Cloud  

NASA Astrophysics Data System (ADS)

The Large Magellanic Cloud (LMC), with its proximity to the Milky Way and location well away from the Galactic plane, offers us an excellent opportunity to study the effects of tidal interactions on the formation and evolution of stellar populations in a satellite galaxy. In this work we present results from a program aimed at determining the ages, kinematics, metallicities, distances and spatial distribution of populous clusters in the LMC. To further our understanding of the LMC cluster system, we have acquired near- infrared (NIR) photometry and spectroscopy and combined these data with optical and NIR photometry from the literature. With FORS2 on the VLT, we obtained NIR spectra for more than 800 stars in and around 29 LMC clusters that span a large range of ages (~ 1-13 Gyr) and metallicities (-0.3 [Special characters omitted.] [Fe/H] [Special characters omitted.] -.2.0). We use these spectra to calculate stellar velocities and metallicities, and identify more than 200 members in 28 clusters. Using published photometry, VLT FORS2 images, and archival HST WFPC2 images, we compiled deep optical photometry for 15 clusters. These data extend below each cluster's main sequence turnoff and, combined with our abundances, allow us to break the well known age-metallicity degeneracy and determine unequivocal ages via main sequence fitting (MSF). As the first step in our distance calculations, we use JK s photometry of 14 Galactic open clusters from the 2MASS to calibrate the K -band luminosity of core helium burning red clump stars ([Special characters omitted.] ) as a function of age and metallicity. Next, with ISPI on the CTIO 4m telescope, we imaged 17 LMC clusters in the NIR ( JK' ) down to K' ~ 18.5, or about 1.5 mag below the RC, allowing us to measure the apparent K -band RC magnitude of each cluster. We combine the LMC cluster ages and abundances with our RC calibration to predict [Special characters omitted.] for each cluster and thereby calculate accurate distances and explore the geometry of the cluster system. Cluster velocities are in good argeement with previous results and show that the LMC clusters rotate with disk-like kinematics. Our abundances indicate that the metallicity distribution of the more metal-rich clusters is much tighter than previously believed, with no tail toward solar metallicities. The peak of this distribution is similar to that of the bar, which is in good agreement with dynamical models that suggest that both the restart of cluster formation and the formation of the bar occurred as a result of the first close encounter with the SMC (~ 4 Gyr ago). Cluster ages derived from MSF range from ~1-3 Gyr for all clusters in our sample except ESO 121-SC03 (~ 9 Gyr), the only known cluster in the LMC with an age between ~3-13 Gyr. The intermediate age range, as well as the age of ESO 121-SC03, is similar to previous results. Finally, we find that the spatial distribution of the LMC cluster system is in good ageement with thick, inclined disk geometry found from LMC field stars. In addition, using RR Lyrae based distances, we find that the old globular clusters are also consistent with this geometry. Given the disk-like kinematics of the entire cluster system, this implies that the LMC's disk formed at about the same time as the old clusters, ~ 13 Gyr ago. Combining the LMC geometry with cluster distances, we calculate a distance to the center of the LMC of ( m-M ) 0 = 18.40±0.04±0.08, which is 0.1 mag shorter than the commonly accepted LMC distance.

Grocholski, Aaron J.

390

Population Census of a Large Common Tern Colony with a Small Unmanned Aircraft  

PubMed Central

Small unmanned aircraft systems (UAS) may be useful for conducting high-precision, low-disturbance waterbird surveys, but limited data exist on their effectiveness. We evaluated the capacity of a small UAS to census a large (>6,000 nests) coastal Common tern (Sterna hirundo) colony of which ground surveys are particularly disruptive and time-consuming. We compared aerial photographic tern counts to ground nest counts in 45 plots (5-m radius) throughout the colony at three intervals over a nine-day period in order to identify sources of variation and establish a coefficient to estimate nest numbers from UAS surveys. We also compared a full colony ground count to full counts from two UAS surveys conducted the following day. Finally, we compared colony disturbance levels over the course of UAS flights to matched control periods. Linear regressions between aerial and ground counts in plots had very strong correlations in all three comparison periods (R2 = 0.972–0.989, P < 0.001) and regression coefficients ranged from 0.928–0.977 terns/nest. Full colony aerial counts were 93.6% and 94.0%, respectively, of the ground count. Varying visibility of terns with ground cover, weather conditions and image quality, and changing nest attendance rates throughout incubation were likely sources of variation in aerial detection rates. Optimally timed UAS surveys of Common tern colonies following our method should yield population estimates in the 93–96% range of ground counts. Although the terns were initially disturbed by the UAS flying overhead, they rapidly habituated to it. Overall, we found no evidence of sustained disturbance to the colony by the UAS. We encourage colonial waterbird researchers and managers to consider taking advantage of this burgeoning technology. PMID:25874997

Chabot, Dominique; Craik, Shawn R.; Bird, David M.

2015-01-01

391

Ecological risk assessment in a large river-reservoir. 6: Bioindicators of fish population health  

SciTech Connect

Spatial distribution of contaminants in the sediments and biota of a large reservoir ecosystem were related to a variety of biological responses in fish populations and communities to determine possible relationships between contaminant loading in the environment and fish health. Much of the contaminant inventory in the Clinch River/Watts Bar Reservoir (CR/WBR) system has originated from three US Department of Energy facilities on the Oak Ridge Reservation, which borders this system in its upper reaches. Fish sampled from areas of the CR/WBR system with the highest levels of contaminants in the sediments and biota, primarily mercury and PCBs, had the most dramatic bioindicator responses. The major changes observed were induction of detoxification enzymes, organ dysfunction, increased frequency of histopathological lesions, impaired reproduction, and reduced fish community integrity. Mercury, the dominant contaminant, displayed a decreasing concentration gradient from the upper reaches of Poplar Creek to the lower Clinch River, which was consistent with a downstream gradient in several of the biological responses. A multivariate analysis using all of the individual fish health responses at each site in a discriminant analysis procedure also revealed a downstream gradient in integrated fish health. In Poplar Creek where contaminant concentrations were the highest, statistical correlations were observed between individual bioindicator responses such as contaminant exposure indicators, organ dysfunction, histopathological damage, and reproductive impairment. Relationships between contaminant loading and fish community indices such as species richness and relative abundance, however, were more difficult to establish in Poplar Creek because of the possible dominating influence of food and habitat availability on fish community dynamics. Using a suite of bioindicators that encompass a range of levels of biological organization and response-sensitivity scales improves the probability of identifying cause and effect and helps in distinguishing between natural and anthropogenic sources of stress in aquatic ecosystems.

Adams, S.M.; Bevelhimer, M.S.; Greeley, M.S. Jr.; Levine, D.A. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; Teh, S.J. [Univ. of California, Davis, CA (United States)

1999-04-01

392

Ten-Year Detection Rate of Brain Arteriovenous Malformations in a Large, Multiethnic, Defined Population  

PubMed Central

Background To evaluate whether increased neuroimaging use is associated with increased brain arteriovenous malformation (BAVM) detection, we examined detection rates in Kaiser Permanente Medical Care Program (KPMCP) of Northern California between 1995 and 2004. Methods We reviewed medical records, radiology reports and administrative databases to identify BAVM, intracranial aneurysms (IA: subarachnoid hemorrhage, SAH, and unruptured aneurysms) and other vascular malformations (OVM: dural fistulas, cavernous malformation, Vein of Galen malformation, venous malformation). Poisson regression (with robust standard errors) was used to test for trend. Random effects meta-analysis generated a pooled measure of BAVM detection rate from six studies. Results We identified 401 BAVMs (197 ruptured, 204 unruptured), 570 OVMs, and 2,892 IAs (2,079 SAH, 813 unruptured IA). Detection rates per 100,000 person-years were 1.4 (95% CI=1.3-1.6) for BAVM, 2.0 (1.8-2.3) for OVM, and 10.3 (9.9-10.7) for IA. Neuroimaging utilization increased 12% per year during the time period (P<0.001). Overall, rates increased for IAs (P<0.001), remained stable for OVMs (P=0.858), and decreased for BAVMs (P=0.001). Detection rates increased 15% per year for unruptured IA (P<0.001), with no change in SAH (P=0.903). However, rates decreased 7% per year for unruptured BAVM (P=0.016) and 3% per year for ruptured BAVM (P=0.005). Meta-analysis yielded a pooled BAVM detection rate of 1.3 (1.2-1.4) per 100,000, without heterogeneity between studies (P=0.25). Conclusions Rates for BAVM, OVM and IA in this large, multiethnic population were similar to other series. During 1995-2004, a period of increasing neuroimaging utilization, we did not observe an increased rate of detection of unruptured BAVM, despite increased detection of unruptured IA. PMID:19926839

Gabriel, Rodney A.; Kim, Helen; Sidney, Stephen; McCulloch, Charles E.; Singh, Vineeta; Claiborne Johnston, S.; Ko, Nerissa U.; Achrol, Achal S.; Zaroff, Jonathan G.; Young, William L.

2010-01-01

393

Refractory hypertension: determination of prevalence, risk factors, and comorbidities in a large, population-based cohort.  

PubMed

Refractory hypertension is an extreme phenotype of antihypertensive treatment failure. Participants in the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study, a large (n=30 239), population-based cohort were evaluated to determine the prevalence of refractory hypertension and associated cardiovascular risk factors and comorbidities. Refractory hypertension was defined as uncontrolled blood pressure (systolic/diastolic, ?140/90 mm Hg) on ?5 antihypertensive drug classes. Participants with resistant hypertension (systolic/diastolic, ?140/90 mm Hg on ?3 or <140/90 mm Hg on ?4 antihypertensive classes) and all participants treated for hypertension served as comparator groups. Of 14 809 REGARDS participants receiving antihypertensive treatment, 78 (0.5%) had refractory hypertension. The prevalence of refractory hypertension was 3.6% among participants with resistant hypertension (n=2144) and 41.7% among participants on ?5 antihypertensive drug classes. Among all participants with hypertension, black race, male sex, living in the stroke belt or buckle, higher body mass index, lower heart rate, reduced estimated glomerular filtration rate, albuminuria, diabetes mellitus, and history of stroke and coronary heart disease were associated with refractory hypertension. Compared with resistant hypertension, prevalence ratios for refractory hypertension were increased for blacks (3.00; 95% confidence interval, 1.68-5.37) and those with albuminuria (2.22; 95% confidence interval, 1.40-3.52) and diabetes mellitus (2.09; 95% confidence interval, 1.32-3.31). The median 10-year Framingham risk for coronary heart disease and stroke was higher among participants with refractory hypertension when compared with those with either comparator group. These data indicate that although resistant hypertension is relatively common among treated patients with hypertension, true antihypertensive treatment failure is rare. PMID:24324035

Calhoun, David A; Booth, John N; Oparil, Suzanne; Irvin, Marguerite R; Shimbo, Daichi; Lackland, Daniel T; Howard, George; Safford, Monika M; Muntner, Paul

2014-03-01

394

Estimates and Determinants of Sexual Violence Against Women in the Democratic Republic of Congo  

PubMed Central

Objectives. We sought to provide data-based estimates of sexual violence in the Democratic Republic of Congo (DRC) and describe risk factors for such violence. Methods. We used nationally representative household survey data from 3436 women selected to answer the domestic violence module who took part in the 2007 DRC Demographic and Health Survey along with population estimates to estimate levels of sexual violence. We used multivariate logistic regression to analyze correlates of sexual violence. Results. Approximately 1.69 to 1.80 million women reported having been raped in their lifetime (with 407 397–433 785 women reporting having been raped in the preceding 12 months), and approximately 3.07 to 3.37 million women reported experiencing intimate partner sexual violence. Reports of sexual violence were largely independent of individual-level background factors. However, compared with women in Kinshasa, women in Nord-Kivu were significantly more likely to report all types of sexual violence. Conclusions. Not only is sexual violence more generalized than previously thought, but our findings suggest that future policies and programs should focus on abuse within families and eliminate the acceptance of and impunity surrounding sexual violence nationwide while also maintaining and enhancing efforts to stop militias from perpetrating rape. PMID:21566049

Palermo, Tia; Bredenkamp, Caryn

2011-01-01

395

Sexual health  

PubMed Central

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

Graham, Anna

2004-01-01

396

Female sexual response: the role of drugs in the management of sexual dysfunction  

Microsoft Academic Search

A large component of women’s sexual desire is responsive rather than spontaneous. Therefore, women’s motivation and ability to find and respond to sexual stimuli to experience sexual arousal and subsequent sexual desire is crucial, but complex. In ongoing relationships, a woman’s motivation appears to be largely influenced by her emotional intimacy with her partner and her wish to enhance it.

Rosemary Basson

2001-01-01

397

POPULATION III STAR FORMATION IN LARGE COSMOLOGICAL VOLUMES. I. HALO TEMPORAL AND PHYSICAL ENVIRONMENT  

SciTech Connect

We present a semi-analytic, computationally inexpensive model to identify halos capable of forming a Population III star in cosmological simulations across a wide range of times and environments. This allows for a much more complete and representative set of Population III star forming halos to be constructed, which will lead to Population III star formation simulations that more accurately reflect the diversity of Population III stars, both in time and halo mass. This model shows that Population III and chemically enriched stars coexist beyond the formation of the first generation of stars in a cosmological simulation until at least z {approx} 10, and likely beyond, though Population III stars form at rates that are 4-6 orders of magnitude lower than chemically enriched stars by z = 10. A catalog of more than 40,000 candidate Population III forming halos were identified, with formation times temporally ranging from z = 30 to z = 10, and ranging in mass from 2.3 Multiplication-Sign 10{sup 5} M{sub Sun} to 1.2 Multiplication-Sign 10{sup 10} M{sub Sun }. At early times, the environment that Population III stars form in is very similar to that of halos hosting chemically enriched star formation. At later times Population III stars are found to form in low-density regions that are not yet chemically polluted due to a lack of previous star formation in the area. Population III star forming halos become increasingly spatially isolated from one another at later times, and are generally closer to halos hosting chemically enriched star formation than to another halo hosting Population III star formation by z {approx} 10.

Crosby, Brian D.; O'Shea, Brian W.; Smith, Britton D. [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Turk, Matthew J. [Department of Astronomy, Columbia University, New York, NY 10025 (United States); Hahn, Oliver, E-mail: crosbyb1@msu.edu [Institute for Astronomy, ETH Zurich, CH-8093 Zuerich (Switzerland)

2013-08-20

398

Sexual Dysfunction in Male Iraq and Afghanistan War Veterans: Association with Posttraumatic Stress Disorder and Other Combat-Related Mental Health Disorders: A Population-Based Cohort Study  

PubMed Central

Introduction Mental health disorders are prevalent in the United States, Iraq, and Afghanistan war veterans. Mental illness, including posttraumatic stress disorder (PTSD) with or without psychiatric medications, can increase the risk for male sexual dysfunction, threatening quality of life. Aims We sought to determine the prevalence and correlates of sexual dysfunction among male Iraq and Afghanistan veterans. Methods We performed a retrospective cohort study of 405,275 male Iraq and Afghanistan veterans who were new users of U.S. Department of Veterans Affairs healthcare from October 7, 2001 to September 30, 2009 and had 2-year follow-up. Main Outcome Measures We determined the independent association of mental health diagnoses and sexual dysfunction after adjusting for sociodemographic and military service characteristics, comorbidities, and medications. Results Veterans with PTSD were more likely to have a sexual dysfunction diagnosis, be prescribed medications for sexual dysfunction, or both (10.6%), compared with veterans having a mental diagnosis other than PTSD (7.2%), or no mental health diagnosis (2.3%). In a fully adjusted model, PTSD increased the risk of sexual dysfunction by more than threefold (adjusted risk ratio = 3.61, 95% CI = 3.48–3.75). Veterans with mental health disorders, particularly PTSD, were at the highest risk of sexual dysfunction when prescribed psychiatric medications (adjusted risk ratio = 4.59, 95% CI = 4.41–4.77). Conclusions Among U.S. combat veterans, mental health disorders, particularly PTSD, increased the risk of sexual dysfunction independent of the use of psychiatric medications. PMID:23679562

Breyer, Benjamin N.; Cohen, Beth E.; Bertenthal, Daniel; Rosen, Raymond C.; Neylan, Thomas C.; Seal, Karen H.

2014-01-01

399

The role of tetraploids in the sexual–asexual cycle in dandelions (Taraxacum)  

Microsoft Academic Search

Apomictic plants often produce pollen that can function in crosses with related sexuals. Moreover, facultative apomicts can produce some sexual offspring. In dandelions, Taraxacum, a sexual–asexual cycle between diploid sexuals and triploid apomicts, has been described, based on experimental crosses and population genetic studies. Little is known about the actual hybridization processes in nature. We therefore studied the sexual–asexual cycle

M. H. Verduijn; P J Van Dijk; J. M. M. Van Damme

2004-01-01

400

mechanisms potentially responsible for the large-scale human population- biodiversity correlation for Formicidae in Europe  

Microsoft Academic Search

Aim Recent coarse-scale studies have shown positive relationships between the biodiversity of plants\\/vertebrates and the human population. Little is known about the generality of the pattern for invertebrates. Moreover, biodiversity and human population might correlate because they both covary with other factors such as energy availability and habitat heterogeneity. Here we test these two non- mutually exclusive mechanisms with ant

Birgit C. Schlick-Steiner; Florian M. Steiner; Marco Pautasso

401

Feasibility of Indexing Large Mouth Bass Population Density Using Electrofishing Catch Rates and  

E-print Network

:..;"~i.~;i~iI~:~~.·:)....~:~~~·~"~·~~l·.::t: ;.j::~" '.. .~ ~.;~ . #12;Feasibility of Indexing Largemouth Bass population Density Using is a standard tool for sampling largemouth bass Micropterus salmoides, but high water conductivity levels hamper electrofishing effectiveness. Population estimates (Petersen method) were determined for largemouth bass in 12

402

Population biology of eyeflukes in fish from a large fluvial ecosystem: the importance of gulls and habitat characteristics  

Microsoft Academic Search

Spottail shiners (Notropis hudsonius) were monitored for eyeflukes monthly at four sites in the St. Lawrence River, Quebec, from spring through autumn in 1997 and 1998. In general, mean abundance of Diplostomum spp. in the lens of spottail shiners was highest at sites near large ring-billed gull ( Larus delawarensis) colonies and was higher in 1998 than in 1997. Population

D. J. Marcogliese; S. Compagna; E. Bergeron; J. D. McLaughlin

2001-01-01

403

Institutions serving a large population of Asian American and Native American Pacific Islander-Serving Institutions (AANAPISIs) have also  

E-print Network

Institutions serving a large population of Asian American and Native American Pacific Islander and Native American Pacific Islander-serving institution' means an institution of higher education of undergraduate students that is not less than 10 percent stu- dents who are Asian American or Native American

Hemmers, Oliver

404

1374 VOLUME 114 | NUMBER 9 | September 2006 Environmental Health Perspectives Large-scale, population-based epidemiologic  

E-print Network

-scale, population-based epidemiologic investigations of the health effects of ambient air pollution often rely in the large majority of locations, spatial estimation methods using geographic information systems (GIS methods. Important methodologic and practical issues still need to be resolved, however. This study

Short, Daniel

405

Sexuality for women with spinal cord injury.  

PubMed

The authors conducted a review of the literature on women's sexuality after spinal cord injury, including studies from 1990 to 2011 retrieved from PubMed. Several facets of a woman's sexuality are negatively affected by after spinal cord injury, and consequently, sexual satisfaction has been shown to decrease, which also negatively affects quality of life. Neurogenic bladder is common after spinal cord injury, and the resulting urinary incontinence is a top therapeutic priority of this population. To improve sexual satisfaction and quality of life for women with spinal cord injury, future research needs to explore the effects of urinary incontinence on various aspects of sexuality. PMID:24325679

Cramp, Jackie D; Courtois, Frédérique J; Ditor, David S

2015-01-01

406

Self-reported history of sexually transmissible infections (STIs) and STI-related utilization of the German health care system by men who have sex with men: data from a large convenience sample  

PubMed Central

Background In Germany, testing and treatment of sexually transmissible infections (STIs) services are not provided by one medical discipline, but rather dispersed among many different providers. Common STIs like gonorrhoea or Chlamydia infection are not routinely reported. Although men who have sex with men (MSM) are particularly vulnerable to STIs, respective health care utilization among MSM is largely unknown. Methods A sexual behaviour survey among MSM was conducted in 2006. Questions on self-reported sexual behaviour, STI-related health care consultation and barriers to access, coverage of vaccination against hepatitis, screening for asymptomatic STIs, self-reported history of STIs, and partner notification were analysed. Analysis was stratified by HIV-serostatus (3,511 HIV-negative/unknown versus 874 positive). Results General Practitioners, particularly gay doctors, were preferred for STI-related health care. Low threshold testing in sex-associated venues was acceptable for most respondents. Shame and fear of homophobic reactions were the main barriers for STI-testing. More than half of the respondents reported vaccination against hepatitis A/B. HIV-positive MSM reported screening offers for STIs three to seven times more often than HIV-negative or untested MSM. Unlike testing for syphilis or hepatitis C, screening for asymptomatic pharyngeal and rectal infections was rarely offered. STIs in the previous twelve months were reported by 7.1% of HIV-negative/untested, and 34.7% of HIV-positive respondents. Conclusions Self-reported histories of STIs in MSM convenience samples differ significantly by HIV-serostatus. Higher rates of STIs among HIV-positive MSM may partly be explained by more testing. Communication between health care providers and their clients about sexuality, sexual practices, and sexual risks should be improved. A comprehensive STI screening policy for MSM is needed. PMID:21592342

2011-01-01

407

Sexual reproduction and recombination in the aflatoxin-producing fungus Aspergillus parasiticus  

Technology Transfer Automated Retrieval System (TEKTRAN)

The fungal phylum Ascomycota comprises a large proportion of species with no known sexual stage, despite high genetic variability in field populations. One such asexual species, Aspergillus parasiticus, is a potent producer of carcinogenic and hepatotoxic aflatoxins, polyketide-derived secondary me...

408

The impact of climate change on the bottom up regulation of density dependence in large herbivore populations  

NASA Astrophysics Data System (ADS)

Population dynamics are regulated by either density dependent or, independent (environmental) factors, and climate change may influence populations through either pathway. One key factor in the population dynamics of large herbivores is the dynamics of vegetation nutrient content, which although being an environmental factor, has the potential to impact the degree of density dependence that regulates population dynamics. To understand this bottom up regulatory mechanism and how climate interacts with vegetation, we will estimate the influence of vegetation dynamics on annual abundance estimates of multiple vertebrate populations using time-series analysis. We will test the hypothesis that the strength of density dependence is expected to vary inversely with changes in vegetation availability, i.e., in areas with higher forage abundance and quality, density dependence is expected to be stronger. Extended to climate change, this hypothesis predicts that climate impacts will be stronger in areas of low vegetation availability, such as the arctic and alpine regions. We will analyze a combined dataset of 55 globally distributed Cervus (elk/red deer) and Rangifer (caribou/reindeer) populations that inhabit areas >100km2. These population time-series we will be analyzed using Markov Chain Monte Carlo Bayesian state-space models, and to represent annual vegetation dynamics we will use Global Inventory Monitoring and Modeling System (GIMMS) normalized difference vegetation index (NDVI) data (i.e., third generation GIMMS NDVI from AVHRR sensors).

Ahrestani, F.; Smith, W. A.; Hebblewhite, M.; Running, S. W.; Post, E.

2013-12-01

409

Sexual conflict over mating in lygaeus seed bugs   

E-print Network

Sexual conflict has been proposed to be important for evolution, and is often implicated in population divergence and speciation through sexually antagonistic co-evolution (SAC). However, empirical tests of these ideas ...

Evans, Gethin Meirion Vaughan

2011-11-24

410

Sexually Aggressive College Males  

ERIC Educational Resources Information Center

The accumulated evidence of this paper suggests that sex aggression is largely the consequence of a particular type of socialization coupled with appropriate situational factors. These males tend to be generally aggressive; they show a strong tendency to deny love feeling for their mothers; their peers tend to stress sexual activity. (Author/BY)

Kanin, Eugene J.

1971-01-01

411

Delayed sleep phase syndrome in adolescents: prevalence and correlates in a large population based study  

PubMed Central

Background The aims of this study were to estimate the prevalence of Delayed Sleep Phase Syndrome (DSPS) in adolescence, and to examine the association to insomnia and school non-attendance. Methods Data stem from a large population based study in Hordaland County in Norway conducted in 2012, the ung@hordaland study. In all, 10,220 adolescents aged 16–18 years (54% girls) provided self-reported data on a range of sleep parameters: DSPS was defined according to the International Classification of Sleep Disorders, Revised (ICSD-R) criteria, while insomnia was defined according to the Quantitative Criteria for Insomnia. Other sleep parameters included time in bed, sleep duration, sleep efficiency, oversleeping, sleep onset latency, wake after sleep onset, subjective sleep need, sleep deficiency, sleepiness and tiredness. Sleep data were calculated separately for weekdays and weekends. Data on school non-attendance were provided by official registers. Results The prevalence of DSPS was 3.3%, and significantly higher among girls (3.7%) than boys (2.7%). There was a strong overlap between DSPS and insomnia, with more than half of the adolescents with DSPS also meeting the criteria for insomnia (53.8% for boys and 57.1% for girls). Adolescents with DSPS had significantly higher odds ratios (OR) of non-attendance at school. After adjusting for sociodeographical factors, insomnia and depression, the adjusted ORs for days of non-attendance were OR?=?3.22 (95% CI: 1.94-5.34) for boys and OR?=?1.87 (95% CI: 1.25-2.80) for girls. A similar effect was found for hours of non-attendance for boys, with an adjusted OR?=?3.05 (95% CI: 1.89-4.92). The effect for girls was no longer significant after full adjustment (OR =1.48 [95% CI: 0.94-2.32]). Conclusions This is one of the first studies to estimate the prevalence of DSPS in adolescents. The high prevalence of DSPS, and overlap with insomnia, in combination with the odds of school non-attendance, suggest that a broad and thorough clinical approach is warranted when adolescents present with symptoms of DSPS. PMID:24330358

2013-01-01

412

RAPID COMMUNICATION Sexually Mature Cuttlefish are Attracted  

E-print Network

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

Boal, Jean

413

Dynamics of an emerging disease drive large-scale amphibian population extinctions.  

PubMed

Epidemiological theory generally suggests that pathogens will not cause host extinctions because the pathogen should fade out when the host population is driven below some threshold density. An emerging infectious disease, chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) is directly linked to the recent extinction or serious decline of hundreds of amphibian species. Despite continued spread of this pathogen into uninfected areas, the dynamics of the host-pathogen interaction remain unknown. We use fine-scale spatiotemporal data to describe (i) the invasion and spread of Bd through three lake basins, each containing multiple populations of the mountain yellow-legged frog, and (ii) the accompanying host-pathogen dynamics. Despite intensive sampling, Bd was not detected on frogs in study basins until just before epidemics began. Following Bd arrival in a basin, the disease spread to neighboring populations at approximately 700 m/yr in a wave-like pattern until all populations were infected. Within a population, infection prevalence rapidly reached 100% and infection intensity on individual frogs increased in parallel. Frog mass mortality began only when infection intensity reached a critical threshold and repeatedly led to extinction of populations. Our results indicate that the high growth rate and virulence of Bd allow the near-simultaneous infection and buildup of high infection intensities in all host individuals; subsequent host population crashes therefore occur before Bd is limited by density-dependent factors. Preventing infection intensities in host populations from reaching this threshold could provide an effective strategy to avoid the extinction of susceptible amphibian species in the wild. PMID:20457913

Vredenburg, Vance T; Knapp, Roland A; Tunstall, Tate S; Briggs, Cheryl J

2010-05-25

414

Dynamics of an emerging disease drive large-scale amphibian population extinctions  

PubMed Central

Epidemiological theory generally suggests that pathogens will not cause host extinctions because the pathogen should fade out when the host population is driven below some threshold density. An emerging infectious disease, chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) is directly linked to the recent extinction or serious decline of hundreds of amphibian species. Despite continued spread of this pathogen into uninfected areas, the dynamics of the host–pathogen interaction remain unknown. We use fine-scale spatiotemporal data to describe (i) the invasion and spread of Bd through three lake basins, each containing multiple populations of the mountain yellow-legged frog, and (ii) the accompanying host–pathogen dynamics. Despite intensive sampling, Bd was not detected on frogs in study basins until just before epidemics began. Following Bd arrival in a basin, the disease spread to neighboring populations at ?700 m/yr in a wave-like pattern until all populations were infected. Within a population, infection prevalence rapidly reached 100% and infection intensity on individual frogs increased in parallel. Frog mass mortality began only when infection intensity reached a critical threshold and repeatedly led to extinction of populations. Our results indicate that the high growth rate and virulence of Bd allow the near-simultaneous infection and buildup of high infection intensities in all host individuals; subsequent host population crashes therefore occur before Bd is limited by density-dependent factors. Preventing infection intensities in host populations from reaching this threshold could provide an effective strategy to avoid the extinction of susceptible amphibian species in the wild. PMID:20457913

Vredenburg, Vance T.; Knapp, Roland A.; Tunstall, Tate S.; Briggs, Cheryl J.

2010-01-01

415

Clonal growth is enhanced in the absence of a mating morph: a comparative study of fertile stylar polymorphic and sterile monomorphic populations of Nymphoides montana (Menyanthaceae)  

PubMed Central

Background and Aims Many aquatic species with stylar polymorphisms have the capacity for clonal and sexual reproduction and are sensitive to the balance of the two reproductive modes when there are a limited number of mating morphs within a population. This study asked how the clonal and sexual reproductive modes perform in populations that contain only a single morph and where fitness gain through sexual