Using Approximate Bayesian Computation to infer sex ratios from acoustic data.

Science.gov (United States)

Lehnen, Lisa; Schorcht, Wigbert; Karst, Inken; Biedermann, Martin; Kerth, Gerald; Puechmaille, Sebastien J

2018-01-01

Population sex ratios are of high ecological relevance, but are challenging to determine in species lacking conspicuous external cues indicating their sex. Acoustic sexing is an option if vocalizations differ between sexes, but is precluded by overlapping distributions of the values of male and female vocalizations in many species. A method allowing the inference of sex ratios despite such an overlap will therefore greatly increase the information extractable from acoustic data. To meet this demand, we developed a novel approach using Approximate Bayesian Computation (ABC) to infer the sex ratio of populations from acoustic data. Additionally, parameters characterizing the male and female distribution of acoustic values (mean and standard deviation) are inferred. This information is then used to probabilistically assign a sex to a single acoustic signal. We furthermore develop a simpler means of sex ratio estimation based on the exclusion of calls from the overlap zone. Applying our methods to simulated data demonstrates that sex ratio and acoustic parameter characteristics of males and females are reliably inferred by the ABC approach. Applying both the ABC and the exclusion method to empirical datasets (echolocation calls recorded in colonies of lesser horseshoe bats, Rhinolophus hipposideros) provides similar sex ratios as molecular sexing. Our methods aim to facilitate evidence-based conservation, and to benefit scientists investigating ecological or conservation questions related to sex- or group specific behaviour across a wide range of organisms emitting acoustic signals. The developed methodology is non-invasive, low-cost and time-efficient, thus allowing the study of many sites and individuals. We provide an R-script for the easy application of the method and discuss potential future extensions and fields of applications. The script can be easily adapted to account for numerous biological systems by adjusting the type and number of groups to be

Maternal Eating Disorders Influence Sex Ratio at Birth

OpenAIRE

Bulik, Cynthia M; Von Holle, Ann; Gendall, Kelly; Kveim Lie, Kari; Hoffman, Elizabeth; Mo, Xiaofei; Torgersen, Leila; Reichborn-Kjennerud, Ted

2008-01-01

We explored sex ratio at birth, defined as the proportion of male live births, in women with anorexia nervosa, bulimia nervosa, binge eating disorder, and eating disorders not otherwise specified-purging type (EDNOS-P) relative to a referent group in a large population based sample of 38,340 pregnant women in Norway. Poisson regressions were adjusted for mother’s age, pre-pregnancy BMI, lifetime smoking status, maternal education, income, marital status, gestational age, and parity. Lower pro...

Association of secondary sex ratio with smoking and parity.

Science.gov (United States)

Beratis, Nicholas G; Asimacopoulou, Aspasia; Varvarigou, Anastasia

2008-03-01

To assess the sex ratio in offspring of smoking and nonsmoking mothers in relationship to parity. Prospective study. University hospital. The authors studied 2,108 term singleton neonates born between 1993 and 2002, 665 from smoking mothers and 1,443 from nonsmoking mothers. A prospective recording of maternal age, parity and smoking status, and gender of neonates delivered over a 10-year period. Secondary sex ratio in regard to maternal smoking and parity. The offspring sex ratio in the total sample studied was 1.09; in the offspring of smoking and nonsmoking mothers, it was 1.26 and 1.03, respectively, a statistically significant difference. In the offspring of smoking women who had parity 1, 2, and >or=3, it was 1.47, 1.35, and 0.92, whereas in those of nonsmoking women, it was 1.04, 1.00, and 1.03, respectively (the differences of the parity 1 and 2 groups between the offspring of smoking and nonsmoking mothers were statistically significant). Logistic regression analysis showed that the possibility of a boy being delivered by a mother who smoked was significantly greater in primiparous women than in women who had parity >or=3, independent of the maternal age. Conversely, parity did not affect significantly the sex ratio in the offspring of nonsmoking women. The findings suggest that among women who smoked, significantly more male than female offspring are born from primiparous women, whereas women who had parity >or=3 gave birth to more female offspring; biparous women give birth to significantly more male offspring, but the offspring sex ratio declined with the number of cigarettes when the mothers smoked >or=10 cigarettes per day.

Sex ratio variation and sex determination in Urtica dioica

NARCIS (Netherlands)

Glawe, Grit Anja

2006-01-01

This thesis will first document on variation in progeny sex ratios among individual female plants of Urtica dioica at our field site in Meijendel (Chapter 2). Next, we show that there is also considerable sex ratio variation among male and female flowering shoots in 26 natural populations studied

Curious Sex Ratios and Cytoplasmic Genes

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 6. Curious Sex Ratios and Cytoplasmic Genes Microbes Can Distort the Sex Ratio of Populations. Stephen J Freeland Laurence D Hurst. General Article Volume 2 Issue 6 June 1997 pp 68-78 ...

Ownership of dwelling affects the sex ratio at birth in Uganda.

Directory of Open Access Journals (Sweden)

Bernard Wallner

Full Text Available BACKGROUND: Socio-economic conditions can affect the secondary sex ratio in humans. Mothers under good environmental conditions are predicted to increase the birth rates of sons according to the Trivers-Willard hypothesis (TWH. This study analyzed the effects of ownership and non-ownership of dwellings on the sex ratio at birth (SRB on a Ugandan sample. METHODOLOGY/PRINCIPAL FINDINGS: Our investigation included 438,640 mothers aged between 12 and 54 years. The overall average SRB was 0.5008. Mothers who live in owned dwellings gave increased births to sons (0.5019 compared to those who live in non-owned dwellings (0.458. Multivariate statistics revealed the strongest effects of dwelling ownership when controlling for demographic and social variables such as marital status, type of marriage, mothers' age, mothers' education, parity and others. CONCLUSIONS/SIGNIFICANCE: The results are discussed in the framework of recent plausible models dealing with the adjustment of the sex ratio. We conclude that the aspect of dwelling status could represent an important socio-economic parameter in relation to SRB variations in humans if further studies are able to analyze it between different countries in a comparative way.

Ownership of dwelling affects the sex ratio at birth in Uganda.

Science.gov (United States)

Wallner, Bernard; Fieder, Martin; Seidler, Horst

2012-01-01

Socio-economic conditions can affect the secondary sex ratio in humans. Mothers under good environmental conditions are predicted to increase the birth rates of sons according to the Trivers-Willard hypothesis (TWH). This study analyzed the effects of ownership and non-ownership of dwellings on the sex ratio at birth (SRB) on a Ugandan sample. Our investigation included 438,640 mothers aged between 12 and 54 years. The overall average SRB was 0.5008. Mothers who live in owned dwellings gave increased births to sons (0.5019) compared to those who live in non-owned dwellings (0.458). Multivariate statistics revealed the strongest effects of dwelling ownership when controlling for demographic and social variables such as marital status, type of marriage, mothers' age, mothers' education, parity and others. The results are discussed in the framework of recent plausible models dealing with the adjustment of the sex ratio. We conclude that the aspect of dwelling status could represent an important socio-economic parameter in relation to SRB variations in humans if further studies are able to analyze it between different countries in a comparative way.

Ownership of Dwelling Affects the Sex Ratio at Birth in Uganda

Science.gov (United States)

Wallner, Bernard; Fieder, Martin; Seidler, Horst

2012-01-01

Background Socio-economic conditions can affect the secondary sex ratio in humans. Mothers under good environmental conditions are predicted to increase the birth rates of sons according to the Trivers-Willard hypothesis (TWH). This study analyzed the effects of ownership and non-ownership of dwellings on the sex ratio at birth (SRB) on a Ugandan sample. Methodology/Principal Findings Our investigation included 438,640 mothers aged between 12 and 54 years. The overall average SRB was 0.5008. Mothers who live in owned dwellings gave increased births to sons (0.5019) compared to those who live in non-owned dwellings (0.458). Multivariate statistics revealed the strongest effects of dwelling ownership when controlling for demographic and social variables such as marital status, type of marriage, mothers’ age, mothers’ education, parity and others. Conclusions/Significance The results are discussed in the framework of recent plausible models dealing with the adjustment of the sex ratio. We conclude that the aspect of dwelling status could represent an important socio-economic parameter in relation to SRB variations in humans if further studies are able to analyze it between different countries in a comparative way. PMID:23284697

Sex allocation and secondary sex ratio in Cuban boa ( Chilabothrus angulifer): mother's body size affects the ratio between sons and daughters

Science.gov (United States)

Frynta, Daniel; Vejvodová, Tereza; Šimková, Olga

2016-06-01

Secondary sex ratios of animals with genetically determined sex may considerably deviate from equality. These deviations may be attributed to several proximate and ultimate factors. Sex ratio theory explains some of them as strategic decisions of mothers improving their fitness by selective investment in sons or daughters, e.g. local resource competition hypothesis (LRC) suggests that philopatric females tend to produce litters with male-biased sex ratios to avoid future competition with their daughters. Until now, only little attention has been paid to examine predictions of sex ratio theory in snakes possessing genetic sex determination and exhibiting large variance in allocation of maternal investment. Cuban boa is an endemic viviparous snake producing large-bodied newborns (˜200 g). Extremely high maternal investment in each offspring increases importance of sex allocation. In a captive colony, we collected breeding records of 42 mothers, 62 litters and 306 newborns and examined secondary sex ratios (SR) and sexual size dimorphism (SSD) of newborns. None of the examined morphometric traits of neonates appeared sexually dimorphic. The sex ratio was slightly male biased (174 males versus 132 females) and litter sex ratio significantly decreased with female snout-vent length. We interpret this relationship as an additional support for LRC as competition between mothers and daughters increases with similarity of body sizes between competing snakes.

Human semen quality and the secondary sex ratio.

Science.gov (United States)

Bae, Jisuk; Kim, Sungduk; Chen, Zhen; Eisenberg, Michael L; Buck Louis, Germaine M

2017-01-01

The aim of this study was to evaluate the association between semen quality and the secondary sex ratio (SSR), defined as the ratio of male to female live births. Our study cohort comprised 227 male partners who were enrolled prior to conception in Michigan and Texas between 2005 and 2009, and prospectively followed through delivery of a singleton birth. The male partners provided a baseline and a follow-up semen sample a month apart. Semen analysis was conducted to assess 27 parameters including five general characteristics, six sperm head measures, 14 morphology measures, and two sperm chromatin stability assay measures. Modified Poisson regression models with a robust error variance were used to estimate the relative risk (RR) and 95% confidence interval (95% CI) of a male birth for each semen parameter, after adjusting for potential confounders. Of the 27 semen parameters, only the percentage of bicephalic sperm was significantly associated with the SSR (2 nd vs 1 st quartile, RR, 0.65, 95% CI, 0.45-0.95, P = 0.03; 4 th vs 1 st quartile, RR, 0.61, 95% CI, 0.38-1.00, P semen quality is associated with offspring sex determination.

Preconception maternal polychlorinated biphenyl concentrations and the secondary sex ratio

International Nuclear Information System (INIS)

Taylor, Kira C.; Jackson, Leila W.; Lynch, Courtney D.; Kostyniak, Paul J.; Buck Louis, Germaine M.

2007-01-01

The secondary sex ratio is the ratio of male to female live births and historically has ranged from 102 to 106 males to 100 females. Temporal declines have been reported in many countries prompting authors to hypothesize an environmental etiology. Blood specimens were obtained from 99 women aged 24-34 prior to attempting pregnancy and quantified for 76 polychlorinated biphenyl (PCB) congeners using dual column gas chromatography with electron capture detection. Women were prospectively followed until pregnancy or 12 cycles of trying. The odds of a male birth for three PCB groupings (total, estrogenic, anti-estrogenic) controlling for maternal characteristics were estimated using logistic regression. Among the 50 women with live births and PCB data, 26 female and 24 male infants were born (ratio 0.92). After adjusting for age and body mass index, odds of a male birth were elevated among women in the second (OR=1.29) and third (OR=1.48) tertiles of estrogenic PCBs; odds (OR=0.70) were reduced among women in the highest tertile of anti-estrogenic PCBs. All confidence intervals included one. The direction of the odds ratios in this preliminary study varied by PCB groupings, supporting the need to study specific PCB patterns when assessing environmental influences on the secondary sex ratio

Local offspring density and sex ratio affect sex allocation in the great tit

NARCIS (Netherlands)

Michler, Stephanie P. M.; Nicolaus, Marion; van der Velde, Marco; Radersma, Reinder; Ubels, Richard; Both, Christiaan; Komdeur, Jan; Tinbergen, Joost M.

2013-01-01

The expected fitness gain for offspring of a given sex may depend on local population sex ratio and density. Knowing the influence of such social factors on brood sex ratios may contribute considerably to the understanding of sex allocation in higher vertebrates. For 3 consecutive years, we

High sex ratios in rural China: declining well-being with age in never-married men.

Science.gov (United States)

Zhou, Xudong; Hesketh, Therese

2017-09-19

In parts of rural China male-biased sex ratios at birth, combined with out-migration of women, have led to highly male-biased adult sex ratios, resulting in large numbers of men being unable to marry, in a culture where marriage and reproduction are an expectation. The aim of this study was to test the hypotheses that older unmarried men are more predisposed to depression, low self-esteem and aggression than both those who are married, and those who are younger and unmarried. Self-completion questionnaires were administered among men aged 20-40 in 48 villages in rural Guizhou province, southwestern China. Tools used included the Beck Depression Inventory, the Rosenberg's Self-esteem Scale and the Bryant-Smith Aggression Questionnaire. Regression models assessed psychological wellbeing while adjusting for socio-demographic variables. Completed questionnaires were obtained from 957 never-married men, 535 married men aged 30-40, 394 partnered men and 382 unpartnered men aged 20-29. After adjusting for socio-demographic variables, never-married men were more predisposed to depression ( p self-esteem ( p < 0.05) and suicidal tendencies ( p < 0.001). All the psychological measures deteriorated with age in never-married men. In contrast, married men remained stable on these dimensions with age. Never-married men are a psychologically highly vulnerable group in a society where marriage is an expectation. Since the highest birth sex-ratio cohorts have not yet reached reproductive age, the social tragedy of these men will last for at least another generation.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'. © 2017 The Authors.

Offspring sex ratios in relation to mutual ornamentation and extra-pair paternity in the Black Swan Cygnus atratus

NARCIS (Netherlands)

Kraaijeveld, Ken; Ming, Ma; Komdeur, Jan; Mulder, Raoul A.

In sexually dichromatic birds, females may adaptively adjust the sex ratio of their offspring prior to hatching in relation to male ornamentation, for example, by producing more sons when paired to a highly attractive partner. However, to our knowledge no studies have investigated offspring sex

Skewed sex ratios in India: "physician, heal thyself".

Science.gov (United States)

Patel, Archana B; Badhoniya, Neetu; Mamtani, Manju; Kulkarni, Hemant

2013-06-01

Sex selection, a gender discrimination of the worst kind, is highly prevalent across all strata of Indian society. Physicians have a crucial role in this practice and implementation of the Indian Government's Pre-Natal Diagnostic Techniques Act in 1996 to prevent the misuse of ultrasound techniques for the purpose of prenatal sex determination. Little is known about family preferences, let alone preferences among families of physicians. We investigated the sex ratios in 946 nuclear families with 1,624 children, for which either one or both parents were physicians. The overall child sex ratio was more skewed than the national average of 914. The conditional sex ratios decreased with increasing number of previous female births, and a previous birth of a daughter in the family was associated with a 38 % reduced likelihood of a subsequent female birth. The heavily skewed sex ratios in the families of physicians are indicative of a deeply rooted social malady that could pose a critical challenge in correcting the sex ratios in India.

Invited review: sex ratio and rheumatic disease.

Science.gov (United States)

Lockshin, M D

2001-11-01

Human illnesses affect men and women differently. In some cases (diseases of sex organs, diseases resulting from X or Y chromosome mutations), reasons for sex discrepancy are obvious, but in other cases no reason is apparent. Explanations for sex discrepancy of illness occur at different biological levels: molecular (e.g., imprinting, X-inactivation), cellular (sex-specific receptor activity), organ (endocrine influences), whole organism (size, age), and environmental-behavioral, including intrauterine influences. Autoimmunity represents a prototypical class of illness that has high female-to-male (F/M) ratios. Although the F/M ratios in autoimmune diseases are usually attributed to the influence of estrogenic hormones, evidence demonstrates that the attributed ratios are imprecise and that definitions and classifications of autoimmune diseases vary, rendering at least part of the counting imprecise. In addition, many studies on sex discrepancy of human disease fail to distinguish between disease incidence and disease severity. In April 2001, the Institute of Medicine of the National Academy of Sciences published Exploring the Biological Contributions to Human Health: Does Sex Matter? (Wizemann T and Pardue M-L, editors). This minireview summarizes the section of that report that concerns autoimmune and infectious disease. Some thyroid, rheumatic, and hepatic autoimmune diseases have high F/M ratios, whereas others have low. Those that have high ratios occur primarily in young adulthood. Gonadal hormones, if they play a role, likely do so through a threshold or permissive mechanism. Examples of sex differences that could be caused by environmental exposure, X inactivation, imprinting, X or Y chromosome genetic modulators, and intrauterine influences are presented as alternate, theoretical, and largely unexplored explanations for sex differences of incidence. The epidemiology of autoimmune diseases (young, female) suggests that an explanation for sex discrepancy of

Do Workplace Sex Ratios Affect Partnership Formation and Dissolution?

DEFF Research Database (Denmark)

Svarer, Michael

In this paper, I analyse the association between workplace sex ratios and partnership formation and dissolution. I find that the risk of dissolution increases with the fraction of coworkers of the opposite sex at both the female and male workplace. On the other hand, workplace sex ratios are not ......In this paper, I analyse the association between workplace sex ratios and partnership formation and dissolution. I find that the risk of dissolution increases with the fraction of coworkers of the opposite sex at both the female and male workplace. On the other hand, workplace sex ratios...

Mother's prior intrauterine position affects the sex ratio of her offspring in house mice.

OpenAIRE

Vandenbergh, J G; Huggett, C L

1994-01-01

Sex ratio alterations related to environmental factors occur in several mammals, but no mechanism has been identified to explain the adjustment. Intrauterine position (IUP) may provide the context in which such alterations occur. Previous studies on house mice and gerbils reveal that the position of a fetus in the uterus in relation to the sex of its neighbors influences its later anatomy, physiology, and behavior. The anogenital distance (AGD) of females located between two males (2M) is lon...

Sex ratios of Mountain Plovers from egg production to fledging

Directory of Open Access Journals (Sweden)

Margaret M. Riordan

2015-12-01

Full Text Available Skewed sex ratios can have negative implications for population growth if they do not match a species' life history. A skewed tertiary sex ratio has been detected in a population of Mountain Plover (Charadrius montanus, a grassland shorebird experiencing population declines. To study the cause of the observed male skew, we examined three early life stages between egg and fledgling in eastern Colorado from 2010 to 2012. This allows us to distinguish between egg production and chick survival as an explanation for the observed skew. We examined the primary sex ratio in eggs produced and the secondary sex ratio in hatched chicks to see if the sex ratio bias occurs before hatching. We also determined the sex ratio at fledging to reveal sex-specific mortality of nestlings. The primary sex ratio was 1.01 (± 0.01 males per female. The secondary sex ratio consisted of 1.10 (± 0.02 males per female. The probability of a chick surviving to fledging differed between males (0.55 ± 0.13 and females (0.47 ± 0.15, but the precision of these survival estimates was low. Sex ratios in early life stages of the Mountain Plover do not explain the skewed sex ratio observed in adults in this breeding population.

Density-dependent sex ratio and sex-specific preference for host traits in parasitic bat flies.

Science.gov (United States)

Szentiványi, Tamara; Vincze, Orsolya; Estók, Péter

2017-08-29

Deviation of sex ratios from unity in wild animal populations has recently been demonstrated to be far more prevalent than previously thought. Ectoparasites are prominent examples of this bias, given that their sex ratios vary from strongly female- to strongly male-biased both among hosts and at the metapopulation level. To date our knowledge is very limited on how and why these biased sex ratios develop. It was suggested that sex ratio and sex-specific aggregation of ectoparasites might be shaped by the ecology, behaviour and physiology of both hosts and their parasites. Here we investigate a highly specialised, hematophagous bat fly species with strong potential to move between hosts, arguably limited inbreeding effects, off-host developmental stages and extended parental care. We collected a total of 796 Nycteribia kolenatii bat flies from 147 individual bats using fumigation and subsequently determined their sex. We report a balanced sex ratio at the metapopulation level and a highly variable sex ratio among infrapopulations ranging from 100% male to 100% female. We show that infrapopulation sex ratio is not random and is highly correlated with infrapopulation size. Sex ratio is highly male biased in small and highly female biased in large infrapopulations. We show that this pattern is most probably the result of sex-specific preference in bat flies for host traits, most likely combined with a higher mobility of males. We demonstrate that female bat flies exert a strong preference for high host body condition and female hosts, while the distribution of males is more even. Our results suggest that locally biased sex ratios can develop due to sex-specific habitat preference of parasites. Moreover, it is apparent that the sex of both hosts and parasites need to be accounted for when a better understanding of host-parasite systems is targeted.

Sex-Ratio and Gender Differences in Depression in an Unselected Adult Population.

Science.gov (United States)

Baumgart, E. P.; Oliver, J. M.

1981-01-01

Neither sex-ratio nor gender differences in depression were found in adult sample, similar to pattern found among university students. No demographic variable was correlated significantly with depression. Suggests results may be due to the elimination of face-to-face interviews, which expose males to greater negative repercussions for exhibiting…

Heritable Variation for Sex Ratio under Environmental Sex Determination in the Common Snapping Turtle (Chelydra Serpentina)

Science.gov (United States)

Janzen, F. J.

1992-01-01

The magnitude of quantitative genetic variation for primary sex ratio was measured in families extracted from a natural population of the common snapping turtle (Chelydra serpentina), which possesses temperature-dependent sex determination (TSD). Eggs were incubated at three temperatures that produced mixed sex ratios. This experimental design provided estimates of the heritability of sex ratio in multiple environments and a test of the hypothesis that genotype X environment (G X E) interactions may be maintaining genetic variation for sex ratio in this population of C. serpentina. Substantial quantitative genetic variation for primary sex ratio was detected in all experimental treatments. These results in conjunction with the occurrence of TSD in this species provide support for three critical assumptions of Fisher's theory for the microevolution of sex ratio. There were statistically significant effects of family and incubation temperature on sex ratio, but no significant interaction was observed. Estimates of the genetic correlations of sex ratio across environments were highly positive and essentially indistinguishable from +1. These latter two findings suggest that G X E interaction is not the mechanism maintaining genetic variation for sex ratio in this system. Finally, although substantial heritable variation exists for primary sex ratio of C. serpentina under constant temperatures, estimates of the effective heritability of primary sex ratio in nature are approximately an order of magnitude smaller. Small effective heritability and a long generation time in C. serpentina imply that evolution of sex ratios would be slow even in response to strong selection by, among other potential agents, any rapid and/or substantial shifts in local temperatures, including those produced by changes in the global climate. PMID:1592234

Curious Sex Ratios and Cytoplasmic Genes

Indian Academy of Sciences (India)

instances of curious sex ratios exemplify an important principle: the fitness ..... markable transition - the whole means of sex determination has changed. No longer ... to the cytoplasmic symbiont is self-evident; the symbionts simply increase the.

Analysis of case-parent trios for imprinting effect using a loglinear model with adjustment for sex-of-parent-specific transmission ratio distortion

DEFF Research Database (Denmark)

Huang, Lam Opal; Infante-Rivard, Claire; Labbe, Aurélie

2017-01-01

Transmission ratio distortion (TRD) is a phenomenon where parental transmission of disease allele to the child does not follow the Mendelian inheritance ratio. TRD occurs in a sex-of-parent-specific or non-sex-of-parent-specific manner. An offset computed from the transmission probability of the ...

Skewed sex ratios and criminal victimization in India.

Science.gov (United States)

South, Scott J; Trent, Katherine; Bose, Sunita

2014-06-01

Although substantial research has explored the causes of India's excessively masculine population sex ratio, few studies have examined the consequences of this surplus of males. We merge individual-level data from the 2004-2005 India Human Development Survey with data from the 2001 India population census to examine the association between the district-level male-to-female sex ratio at ages 15 to 39 and self-reports of victimization by theft, breaking and entering, and assault. Multilevel logistic regression analyses reveal positive and statistically significant albeit substantively modest effects of the district-level sex ratio on all three victimization risks. We also find that higher male-to-female sex ratios are associated with the perception that young unmarried women in the local community are frequently harassed. Household-level indicators of family structure, socioeconomic status, and caste, as well as areal indicators of women's empowerment and collective efficacy, also emerge as significant predictors of self-reported criminal victimization and the perceived harassment of young women. The implications of these findings for India's growing sex ratio imbalance are discussed.

Skewed Sex Ratios and Criminal Victimization in India

Science.gov (United States)

South, Scott J.; Trent, Katherine; Bose, Sunita

2014-01-01

Although substantial research has explored the causes of India’s excessively masculine population sex ratio, few studies have examined the consequences of this surplus of males. We merge individual-level data from the 2004–2005 India Human Development Survey with data from the 2001 India population census to examine the association between the district-level male-to-female sex ratio at ages 15 to 39 and self-reports of victimization by theft, breaking and entering, and assault. Multilevel logistic regression analyses reveal positive and statistically significant albeit substantively modest effects of the district-level sex ratio on all three victimization risks. We also find that higher male-to-female sex ratios are associated with the perception that young unmarried women in the local community are frequently harassed. Household-level indicators of family structure, socioeconomic status, and caste, as well as areal indicators of women’s empowerment and collective efficacy, also emerge as significant predictors of self-reported criminal victimization and the perceived harassment of young women. The implications of these findings for India’s growing sex ratio imbalance are discussed. PMID:24682921

Inter-Annual Variability of Fledgling Sex Ratio in King Penguins.

Directory of Open Access Journals (Sweden)

Célia Bordier

Full Text Available As the number of breeding pairs depends on the adult sex ratio in a monogamous species with biparental care, investigating sex-ratio variability in natural populations is essential to understand population dynamics. Using 10 years of data (2000-2009 in a seasonally monogamous seabird, the king penguin (Aptenodytes patagonicus, we investigated the annual sex ratio at fledging, and the potential environmental causes for its variation. Over more than 4000 birds, the annual sex ratio at fledging was highly variable (ranging from 44.4% to 58.3% of males, and on average slightly biased towards males (51.6%. Yearly variation in sex-ratio bias was neither related to density within the colony, nor to global or local oceanographic conditions known to affect both the productivity and accessibility of penguin foraging areas. However, rising sea surface temperature coincided with an increase in fledging sex-ratio variability. Fledging sex ratio was also correlated with difference in body condition between male and female fledglings. When more males were produced in a given year, their body condition was higher (and reciprocally, suggesting that parents might adopt a sex-biased allocation strategy depending on yearly environmental conditions and/or that the effect of environmental parameters on chick condition and survival may be sex-dependent. The initial bias in sex ratio observed at the juvenile stage tended to return to 1∶1 equilibrium upon first breeding attempts, as would be expected from Fisher's classic theory of offspring sex-ratio variation.

Inter-Annual Variability of Fledgling Sex Ratio in King Penguins.

Science.gov (United States)

Bordier, Célia; Saraux, Claire; Viblanc, Vincent A; Gachot-Neveu, Hélène; Beaugey, Magali; Le Maho, Yvon; Le Bohec, Céline

2014-01-01

As the number of breeding pairs depends on the adult sex ratio in a monogamous species with biparental care, investigating sex-ratio variability in natural populations is essential to understand population dynamics. Using 10 years of data (2000-2009) in a seasonally monogamous seabird, the king penguin (Aptenodytes patagonicus), we investigated the annual sex ratio at fledging, and the potential environmental causes for its variation. Over more than 4000 birds, the annual sex ratio at fledging was highly variable (ranging from 44.4% to 58.3% of males), and on average slightly biased towards males (51.6%). Yearly variation in sex-ratio bias was neither related to density within the colony, nor to global or local oceanographic conditions known to affect both the productivity and accessibility of penguin foraging areas. However, rising sea surface temperature coincided with an increase in fledging sex-ratio variability. Fledging sex ratio was also correlated with difference in body condition between male and female fledglings. When more males were produced in a given year, their body condition was higher (and reciprocally), suggesting that parents might adopt a sex-biased allocation strategy depending on yearly environmental conditions and/or that the effect of environmental parameters on chick condition and survival may be sex-dependent. The initial bias in sex ratio observed at the juvenile stage tended to return to 1∶1 equilibrium upon first breeding attempts, as would be expected from Fisher's classic theory of offspring sex-ratio variation.

National, regional, and global sex ratios of infant, child, and under-5 mortality and identification of countries with outlying ratios: a systematic assessment.

Science.gov (United States)

Alkema, Leontine; Chao, Fengqing; You, Danzhen; Pedersen, Jon; Sawyer, Cheryl C

2014-09-01

Under natural circumstances, the sex ratio of male to female mortality up to the age of 5 years is greater than one but sex discrimination can change sex ratios. The estimation of mortality by sex and identification of countries with outlying levels is challenging because of issues with data availability and quality, and because sex ratios might vary naturally based on differences in mortality levels and associated cause of death distributions. For this systematic analysis, we estimated country-specific mortality sex ratios for infants, children aged 1-4 years, and children under the age of 5 years (under 5s) for all countries from 1990 (or the earliest year of data collection) to 2012 using a Bayesian hierarchical time series model, accounting for various data quality issues and assessing the uncertainty in sex ratios. We simultaneously estimated the global relation between sex ratios and mortality levels and constructed estimates of expected and excess female mortality rates to identify countries with outlying sex ratios. Global sex ratios in 2012 were 1·13 (90% uncertainty interval 1·12-1·15) for infants, 0·95 (0·93-0·97) for children aged 1-5 years, and 1·08 (1·07-1·09) for under 5s, an increase since 1990 of 0·01 (-0·01 to 0·02) for infants, 0·04 (0·02 to 0·06) for children aged 1-4 years, and 0·02 (0·01 to 0·04) for under 5s. Levels and trends varied across regions and countries. Sex ratios were lowest in southern Asia for 1990 and 2012 for all age groups. Highest sex ratios were seen in developed regions and the Caucasus and central Asia region. Decreasing mortality was associated with increasing sex ratios, except at very low infant mortality, where sex ratios decreased with total mortality. For 2012, we identified 15 countries with outlying under-5 sex ratios, of which ten countries had female mortality higher than expected (Afghanistan, Bahrain, Bangladesh, China, Egypt, India, Iran, Jordan, Nepal, and Pakistan). Although excess female

Demographic origins of skewed operational and adult sex ratios: perturbation analyses of two-sex models.

Science.gov (United States)

Veran, Sophie; Beissinger, Steven R

2009-02-01

Skewed sex ratios - operational (OSR) and Adult (ASR) - arise from sexual differences in reproductive behaviours and adult survival rates due to the cost of reproduction. However, skewed sex-ratio at birth, sex-biased dispersal and immigration, and sexual differences in juvenile mortality may also contribute. We present a framework to decompose the roles of demographic traits on sex ratios using perturbation analyses of two-sex matrix population models. Metrics of sensitivity are derived from analyses of sensitivity, elasticity, life-table response experiments and life stage simulation analyses, and applied to the stable stage distribution instead of lambda. We use these approaches to examine causes of male-biased sex ratios in two populations of green-rumped parrotlets (Forpus passerinus) in Venezuela. Female local juvenile survival contributed the most to the unbalanced OSR and ASR due to a female-biased dispersal rate, suggesting sexual differences in philopatry can influence sex ratios more strongly than the cost of reproduction.

Sex ratio and Wolbachia infection in the ant Formica exsecta.

Science.gov (United States)

Keller, L; Liautard, C; Reuter, M; Brown, W D; Sundström, L; Chapuisat, M

2001-08-01

Sex allocation data in social Hymenoptera provide some of the best tests of kin selection, parent-offspring conflict and sex ratio theories. However, these studies critically depend on controlling for confounding ecological factors and on identifying all parties that potentially manipulate colony sex ratio. It has been suggested that maternally inherited parasites may influence sex allocation in social Hymenoptera. If the parasites can influence sex allocation, infected colonies are predicted to invest more resources in females than non-infected colonies, because the parasites are transmitted through females but not males. Prime candidates for such sex ratio manipulation are Wolbachia, because these cytoplasmically transmitted bacteria have been shown to affect the sex ratio of host arthropods by cytoplasmic incompatibility, parthenogenesis, male-killing and feminization. In this study, we tested whether Wolbachia infection is associated with colony sex ratio in two populations of the ant Formica exsecta that have been the subject of extensive sex ratio studies. In these populations colonies specialize in the production of one sex or the other. We found that almost all F. exsecta colonies in both populations are infected with Wolbachia. However, in neither population did we find a significant association in the predicted direction between the prevalence of Wolbachia and colony sex ratio. In particular, colonies with a higher proportion of infected workers did not produce more females. Hence, we conclude that Wolbachia does not seem to alter the sex ratio of its hosts as a means to increase transmission rate in these two populations of ants.

Sex ratio selection and multi-factorial sex determination in the housefly : A dynamic model

NARCIS (Netherlands)

Kozielska, M.A.; Pen, I.R.; Beukeboom, L.W.; Weissing, F.J.

Sex determining (SD) mechanisms are highly variable between different taxonomic groups and appear to change relatively quickly during evolution. Sex ratio selection could be a dominant force causing such changes. We investigate theoretically the effect of sex ratio selection on the dynamics of a

Sex, sex-ratios, and the dynamics of pelagic copepod populations

DEFF Research Database (Denmark)

Kiørboe, Thomas

2006-01-01

equal adult sex ratios in field populations. Winter population densities are orders of magnitude less than the critical population density required for population persistence, but populations survive winter seasons as resting eggs in the sediment. Population growth in these species is potentially high...... because they have on average a factor of 2 higher egg production rates than other pelagic copepods. Secondly, other copepods require only one mating to stay fertile, and populations of these species have strongly female-skewed adult sex-ratios in field populations. Resting eggs have not been described...

Getting past nature as a guide to the human sex ratio.

Science.gov (United States)

Murphy, Timothy F

2013-05-01

Sex selection of children by pre-conception and post-conception techniques remains morally controversial and even illegal in some jurisdictions. Among other things, some critics fear that sex selection will distort the sex ratio, making opposite-sex relationships more difficult to secure, while other critics worry that sex selection will tilt some nations toward military aggression. The human sex ratio varies depending on how one estimates it; there is certainly no one-to-one correspondence between males and females either at birth or across the human lifespan. Complications about who qualifies as 'male' and 'female' complicate judgments about the ratio even further. Even a judiciously estimated sex ratio does not have, however, the kind of normative status that requires society to refrain from antenatal sex selection. Some societies exhibit lopsided sex ratios as a consequence of social policies and practices, and pragmatic estimates of social needs are a better guide to what the sex ratio should be, as against looking to 'nature'. The natural sex ratio cannot be a sound moral basis for prohibiting parents from selecting the sex of their children, since it ultimately lacks any normative meaning for social choices. © 2011 Blackwell Publishing Ltd.

Mother's occupation and sex ratio at birth

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Amiot Volodymyr

2010-05-01

Full Text Available Abstract Background Many women are working outside of the home, occupying a multitude of jobs with varying degrees of responsibilities and levels of psychological stress. We investigated whether different job types in women are associated with child sex at birth, with the hypothesis that women in job types, which are categorized as "high psychological stress" jobs, would be more likely to give birth to a daughter than a son, as females are less vulnerable to unfavourable conditions during conception, pregnancy and after parturition, and are less costly to carry to term. Methods We investigated the effects of mother's age, maternal and paternal job type (and associated psychological stress levels and paternal income on sex ratio at birth. Our analyses were based on 16,384 incidences of birth from a six-year (2000 to 2005 inclusive childbirth dataset from Addenbrooke's Hospital in Cambridge, UK. We obtained a restricted data set from Addenbrooke's hospital with: maternal age, maternal and paternal occupations, and whether or not the child was first-born. Results Women in job types that were categorized as "high stress" were more likely to give birth to daughters, whereas women in job types that were categorized as "low stress" had equal sex ratios or a slight male bias in offspring. We also investigated whether maternal age, and her partner's income could be associated with reversed offspring sex ratio. We found no association between mother's age, her partner's job stress category or partner income on child sex. However, there was an important interaction between job stress category and partner income in some of the analyses. Partner income appears to attenuate the association between maternal job stress and sex ratios at moderate-income levels, and reverse it at high-income levels. Conclusions To our knowledge this is the first report on the association between women's job type stress categories and offspring sex ratio in humans, and the

Secondary sex ratio in relation to exposures to polychlorinated biphenyls, dichlorodiphenyl dichloroethylene and methylmercury

DEFF Research Database (Denmark)

Timmermann, Clara Amalie Gade; Choi, Anna L.; Petersen, Maria Skaalum

2017-01-01

This study was undertaken to assess the potential impact of maternal exposures to polychlorinated biphenyl (PCB), dichlorodiphenyl dichloroethylene (DDE) and methylmercury on the secondary sex ratios (the ratio of male to female live births) over a span of 23 years. The study includes prospective...... data from three Faroese birth cohorts, with a total of 2,152 healthy mother-child dyads recruited between 1986 and 2009. The Faroe Islands is a subarctic fishing community, where pilot whale meat and blubber are part of the traditional marine diet. Exposures were measured in maternal hair, serum...... or umbilical cord blood. Confounder adjusted logistic regression models were used to assess the associations between maternal exposures and the secondary sex ratio. A doubling in ΣPCB, p,p'-DDE and mercury concentrations were associated with increased odds by 8% (95% CI = 0-16%), 7% (95% CI = 0-14%) and 9% (95...

Exploring the possibilities for stabilizing the sex ratio in India

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Saurabh RamBihariLal Shrivastava

2015-12-01

Full Text Available The sex ratio is an important demographic indicator for a nation. A wide range of adverse social consequences have been observed because of a skewed sex ratio in India. If India as a nation is to achieve the Millennium Development Goal – 3 (which promotes gender equality and ensures the empowerment of women, the primary target should be involve all those involved, so that a collective and comprehensive approach can be developed to counter the public health menace of an asymmetrical sex ratio. In conclusion, the nation’s program managers should prioritize the issue of a skewed sex ratio and work towards developing a coordinated response.Key Words: Sex ratio, policy makers, India.

Patterns of Family Formation in Response to Sex Ratio Variation.

Science.gov (United States)

Schacht, Ryan; Kramer, Karen L

2016-01-01

The impact that unbalanced sex ratios have on health and societal outcomes is of mounting contemporary concern. However, it is increasingly unclear whether it is male- or female-biased sex ratios that are associated with family and social instability. From a socio-demographic perspective, male-biased sex ratios leave many men unable to find a mate, elevating competition among males, disrupting family formation and negatively affecting social stability. In contrast, from a mating-market perspective, males are expected to be less willing to marry and commit to a family when the sex ratio is female-biased and males are rare. Here we use U.S. data to evaluate predictions from these competing frameworks by testing the relationship between the adult sex ratio and measures of family formation. We find that when women are rare men are more likely to marry, be part of a family and be sexually committed to a single partner. Our results do not support claims that male-biased sex ratios lead to negative family outcomes due to a surplus of unmarried men. Rather, our results highlight the need to pay increased attention to female-biased sex ratios.

A study to review sex ratio at birth and analyze preferences for the sex of the unborn.

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Warade, Yugali; Balsarkar, Geetha; Bandekar, Pooja

2014-02-01

(1) To study the status of sex ratio at birth with increasing birth order, (2) To ascertain the relationship of declining sex ratio with respect to socio demographic factors. (3) To study outlook of patient towards sex preference, willingness to determine sex of the fetus, wish to terminate the pregnancy in case of unwanted sex of the baby. This is the retrospective study done in the Department of Obstetrics and Gynaecology, Nowrosjee Wadia Maternity Hospital, Parel, Mumbai. The data was collected from the records maintained in Medical Record Department from January 2007 to December 2012 and were studied to determine the sex ratio as well as its relationship with the increasing parity. 95 % confidence interval for the sex ratios was calculated. Average sex ratio of 6 years was 908 females per 1,000 males. Sex ratio was 972 females per 1,000 males in primi para, which decreased to 879 females per 1,000 males in second para, further reduced to 784 females per 1,000 males in third para and 864 females per 1,000 males in fourth para. The 'sex ratio at birth', defined as the number of girls born for every 1,000 boys born, is a more accurate and refined indicator of the extent of prenatal sex selection.

Psychological distress during early gestation and offspring sex ratio

DEFF Research Database (Denmark)

Obel, C; Henriksen, TB; Secher, Niels Jørgen

2007-01-01

BACKGROUND: Exposure to severe stress in early pregnancy is associated with a lower male to female ratio (sex ratio), but whether more moderate levels of psychological discomfort have the same kind of effect is unknown. In a population based follow-up study, we aimed to test whether psychological...... suggest that not only severe stress, but also more moderate and common levels of psychological distress, may decrease the sex ratio in the offspring. Stress during pregnancy is a likely candidate involved in the decreasing sex ratio observed in many countries....... distress was associated with the sex ratio in the offspring. METHODS: From 1989 to 1992, a cohort of 8,719 Danish-speaking pregnant women were followed until delivery. Questionnaires were administered to the women in early pregnancy and 6,629 (76%) completed the 30-item version of the General Health...

Psychological distress during early gestation and offspring sex ratio

DEFF Research Database (Denmark)

Obel, Carsten; Henriksen, Tine Brink; Secher, Niels Jørgen

2007-01-01

BACKGROUND: Exposure to severe stress in early pregnancy is associated with a lower male to female ratio (sex ratio), but whether more moderate levels of psychological discomfort have the same kind of effect is unknown. In a population based follow-up study, we aimed to test whether psychological...... suggest that not only severe stress, but also more moderate and common levels of psychological distress, may decrease the sex ratio in the offspring. Stress during pregnancy is a likely candidate involved in the decreasing sex ratio observed in many countries. Udgivelsesdato: 2007-Nov...... distress was associated with the sex ratio in the offspring. METHODS: From 1989 to 1992, a cohort of 8,719 Danish-speaking pregnant women were followed until delivery. Questionnaires were administered to the women in early pregnancy and 6,629 (76%) completed the 30-item version of the General Health...

Meiotic sex ratio variation in natural populations of Ceratodon purpureus (Ditrichaceae).

Science.gov (United States)

Norrell, Tatum E; Jones, Kelly S; Payton, Adam C; McDaniel, Stuart F

2014-09-01

• Sex ratio variation is a common but often unexplained phenomenon in species across the tree of life. Here we evaluate the hypothesis that meiotic sex ratio variation can contribute to the biased sex ratios found in natural populations of the moss Ceratodon purpureus.• We obtained sporophytes from several populations of C. purpureus from eastern North America. From each sporophyte, we estimated the mean spore viability by germinating replicate samples on agar plates. We estimated the meiotic sex ratio of each sporophyte by inferring the sex of a random sample of germinated spores (mean = 77) using a PCR-RFLP test. We tested for among-sporophyte variation in viability using an ANOVA and for deviations from 1:1 sex ratio using a χ(2)-test and evaluated the relationship between these quantities using a linear regression.• We found among-sporophyte variation in spore viability and meiotic sex ratio, suggesting that genetic variants that contribute to variation in both of these traits segregate within populations of this species. However, we found no relationship between these quantities, suggesting that factors other than sex ratio distorters contribute to variation in spore viability within populations.• These results demonstrate that sex ratio distortion may partially explain the population sex ratio variation seen in C. purpureus, but more generally that genetic conflict over meiotic segregation may contribute to fitness variation in this species. Overall, this study lays the groundwork for future studies on the genetic basis of meiotic sex ratio variation. © 2014 Botanical Society of America, Inc.

Sex ratios in fetuses and liveborn infants with autosomal aneuploidy

Energy Technology Data Exchange (ETDEWEB)

Heuther, C.A.; Martin, R.L.M.; Stoppelman, S.M. [Univ. of Cincinnati, OH (United States)] [and others

1996-06-14

Ten data sources were used substantially to increase the available data for estimating fetal and livebirth sex ratios for Patau (trisomy 13), Edwards (trisomy 18), and Down (trisomy 21) syndromes and controls. The fetal sex ratio estimate was 0.88 (N = 584) for trisomy 13, 0.90 (N = 1702) for trisomy 18, and 1.16 (N = 3154) for trisomy 21. All were significantly different from prenatal controls (1.07). The estimated ratios in prenatal controls were 1.28 (N = 1409) for CVSs and 1.06 (N = 49427) for amniocenteses, indicating a clear differential selection against males, mostly during the first half of fetal development. By contrast, there were no sex ratio differences for any of the trisomies when comparing gestational ages <16 and >16 weeks. The livebirth sex ratio estimate was 0.90 (N = 293) for trisomy 13, 0.63 (N = 497) for trisomy 18, and 1.15 (N = 6424) for trisomy 21, the latter two being statistically different than controls (1.05) (N = 3660707). These ratios for trisomies 13 and 18 were also statistically different than the ratio for trisomy 21. Only in trisomy 18 did the sex ratios in fetuses and livebirths differ, indicating a prenatal selection against males >16 weeks. No effects of maternal age or race were found on these estimates for any of the fetal or livebirth trisomies. Sex ratios for translocations and mosaics were also estimated for these aneuploids. Compared to previous estimates, these results are less extreme, most likely because of larger sample sizes and less sample bias. They support the hypothesis that these trisomy sex ratios are skewed at conception, or become so during embryonic development through differential intrauterine selection. The estimate for Down syndrome livebirths is also consistent with the hypothesis that its higher sex ratio is associated with paternal nondisjunction. 36 refs., 5 tabs.

Sex differences in psychological adjustment from infancy to 8 years.

Science.gov (United States)

Prior, M; Smart, D; Sanson, A; Oberklaid, F

1993-03-01

The objective of this study was to explore sex differences in development from infancy to 8 years of age in a community sample. Measures of biological, social, interactive, and parental functioning as well as teacher reports were obtained. There were minimal differences in infancy, but major psychosocial differences emerged with increasing age. In the biological sphere boys were disadvantaged only in ratings of language and motor skills at 3 to 4 years old. They showed greater temperamental "difficulty" and low persistence factor scores from 5 years onward. Boys were significantly more likely to have problems with adaptive behavior and social competence and to show behavior problems of the hyperactive and aggressive type, as rated by mothers. Parent and family functioning measures did not differentiate between the sexes. Teachers rated boys as having more problems in academic and behavioral domains the first 3 years of school. Path analyses combining data sets gathered when the children were 3 to 8 years old demonstrated the differential courses of development for boys and girls although temperamental flexibility was the best predictor of behavioral adjustment for both sexes. A social learning explanation of the increased incidence of problems among males is supported, although biological influences are not ruled out.

THE ENIGMA OF ETHIOPIAN SEX RATIOS AT BIRTH.

Science.gov (United States)

Garenne, Michel

2017-09-01

This study analysed sex ratios at birth (defined as the number of male births per 100 female births) using data on children ever-born from three censuses conducted in Ethiopia in 1984, 1994 and 2007. The results showed very high values by any standard, with an average of 108.4 for a sample of some 8.2 million births, with somewhat lower values in urban areas. Analysis of socioeconomic correlates revealed that the sex ratio varied very much by household wealth, from about 110 for very poor women to about 102 for wealthier women. The high value of the sex ratio at birth in Ethiopia could be explained by poverty, used as a proxy for poor nutritional status. In multivariate analysis, the effects of living in urban areas and of maternal education were less important than household wealth. Among the many ethno-linguistic groups, the Nilotic family had higher sex ratios than other groups. The results were confirmed using data from DHS surveys conducted in the country, and by the analysis of children still living at time of census.

Exposure to widespread environmental endocrine disrupting chemicals and human sperm sex ratio

International Nuclear Information System (INIS)

Jurewicz, Joanna; Radwan, Michał; Sobala, Wojciech; Radwan, Paweł; Jakubowski, Lucjusz; Wielgomas, Bartosz; Ligocka, Danuta; Brzeźnicki, Sławomir; Hanke, Wojciech

2016-01-01

In recent years, a trend toward a declining proportion of male births has been noted in several, but not all, industrialized countries. The underlying reason for the drop in the sex ratio is unclear, but one theory states that widespread environmental endocrine disrupting chemicals affecting the male reproductive system in a negative manner could be part of the explanation. The present study was designed to investigate whether the urinary phthalate, pyrethroids and polycyclic aromatic hydrocarbons metabolites concentrations were associated with sperm Y:X ratio. The study population consisted of 194 men aged under 45 years of age who attended infertility clinic in Lodz, Poland for diagnostic purposes with normal semen concentration of 20–300 mln/ml or with slight oligozoospermia (semen concentration of 15–20 mln/ml) (WHO, 1999). The Y:X ratio was assessed by fluorescent in situ hybridization. Urinary concentrations of 1-hydroxypyrene were measured by high performance liquid chromatography, phthalate metabolites were analyzed using a procedure based on the LC-MS/MS methods and metabolites of synthetic pyrethroids were assessed by gas chromatography ion-tap mass spectrometry method. After adjustment for potential confounders (past diseases, age, abstinence, smoking, alcohol consumption, sperm concentration, motility, morphology) 5OH MEHP, CDCCA to TDCCA and 1-OHP was negatively related to Y:X sperm chromosome ratio (p = 0.033, p < 0.001, p = 0.047 respectively). As this is the first study to elucidate the association between the level of metabolites of widespread environmental endocrine disrupting chemicals (phthalates, synthetic pyrethroids, polycyclic aromatic hydrocarbons) on sex chromosome ratio in sperm therefore, these findings require further replication in other populations. - Highlights: • Urinary phthalate metabolites levels were significantly associated with a decrease in Y/X chromosome bearing sperm. • The levels of 1-hydroxypyrene in urine

Masculine sex ratios, population age structure and the potential spread of HIV in China

Directory of Open Access Journals (Sweden)

M. Giovanna Merli

2010-01-01

Full Text Available There is much speculation regarding the contribution of China's changing demography to the spread of HIV/AIDS. We employ a bio-behavioral macrosimulation model of the heterosexual spread of HIV/AIDS to evaluate the roles that China's unique demographic conditions -- (1 masculine sex ratios at birth and (2 a population age structure that reflects rapid fertility decline since the 1970's -- play in altering the market for sexual partners, thereby potentially fueling an increase in behaviors associated with greater risk of HIV infection. We first simulate the relative contributions of the sex ratio at birth and the population age structure to the oversupply of males in the market for sexual partners and show that the sex ratio at birth only aggravates the severe oversupply of males which is primarily a consequence of the population age structure. We then examine the potential consequences of this demographic distortion for the spread of HIV infection and show that, to the extent that males adapt to the dearth of suitable female partners by seeking unprotected sexual contacts with female sex workers, the impact of the oversupply of males in the sexual partnership market on the spread of HIV will be severe.

The association between male-biased sex ratio and indicators of stress in red-spotted newts.

Science.gov (United States)

Aspbury, Andrea S; Grayson, Kristine L; Fantaye, Selamawit; Nichols, Ian; Myers-Burton, Miranda; Ortiz-Mangual, Xavier; Gabor, Caitlin R

2017-05-01

In populations with a male-biased operational sex ratio, coercive mating by males can have fitness consequences for females. One component of reduced fitness for females in populations with a male-biased OSR may be greater activation of the stress response, resulting in higher corticosterone release rates (CORT; a glucocorticoid stress hormone in amphibians). We test the hypothesis that a male-biased sex ratio affects female activity and release rates of CORT and testosterone (T) in male and female red-spotted newts (Notophthalmus viridescens). First, we evaluated if chemical cues from a male-biased sex ratio affect activity and CORT release rates in females. We predicted that females exposed to chemical cues of three males would be less active and have higher CORT release rates than those exposed to chemical cues of one male. Second, we measured CORT release rates of red-spotted newts in field enclosures with either a male-biased or a female-biased sex ratio. We predicted that females in the male-biased treatment would have higher CORT and T release rates than those in a female-biased treatment, owing to higher levels of male harassment. We also predicted that males would have higher CORT and T release rates in male-biased treatments due to higher levels of male-male competition. Females were not less active in response to chemical cues from more males over fewer males, but there was a positive relationship between female activity and CORT when they were exposed to the cues of three males. We also found that females, but not males, in the male-biased sex ratio treatment had higher CORT and T release rates than those in the female-biased treatment. Our results support the hypothesis that a male-biased sex ratio leads to a higher stress response, which may underlie the observed decrease in immune function and body condition in previous work exposing female red-spotted newts to a male-biased sex ratio. This study furthers our understanding of the mechanistic basis

Parental correlates of offspring sex ratio in Eurasian Oystercatchers

NARCIS (Netherlands)

Heg, D.; Dingemanse, NJ; Lessells, CM; Mateman, AC

2000-01-01

We investigated hatchling and fledgling sex ratios in Eurasian Oystercatchers (Haematopus ostralegus) using random amplified polymorphic DNA markers. The overall hatchling (53% males, n = 374 hatchlings from 177 broods) and fledgling (49% males, n = 51) sex ratio did not differ significantly from

Human sex ratio at amniocentesis and at birth in Taiwan

Directory of Open Access Journals (Sweden)

I-Wen Lee

2012-12-01

Conclusions: The results showed that sex ratio was already skewed toward male at midtrimester. Our data imply that artificial sex selection, if it were present, might have already emerged prior to the timing of amniocentesis. However, more large nationwide studies on sex ratios in Taiwan are warranted.

The impact of violence on sex risk and drug use behaviors among women engaged in sex work in Phnom Penh, Cambodia.

Science.gov (United States)

Draughon Moret, Jessica E; Carrico, Adam W; Evans, Jennifer L; Stein, Ellen S; Couture, Marie-Claude; Maher, Lisa; Page, Kimberly

2016-04-01

Violence, substance use, and HIV disproportionately impact female entertainment and sex workers (FESW), but causal pathways remain unclear. We examined data from an observational cohort of FESW age 15-29 in Phnom Penh, Cambodia for associations between violence exposure and sexual risk and drug use. Validated measures of physical and sexual violence were assessed at baseline. Self-reported outcomes measured quarterly over the next 12-months included past month sexual partners, consistent condom use by partner type, sex while high, and amphetamine type stimulant (ATS) use. Biomarkers measured quarterly included prostate specific antigen (PSA) and urine toxicology. Generalized estimating equations were fit adjusting for age, education, marital status and sex work venue. Of 220 women, 48% reported physical or sexual violence in the preceding 12-months. Physical violence was associated with increased number of sex partners (adjusted incidence rate ratio [aIRR] 1.33; 95% CI: 1.04-1.71), greater odds of sex while high (adjusted odds ratio [aOR] 2.42; 95% CI: 1.10-5.33), increased days of ATS use (aIRR 2.74; 95% CI: 1.29-5.84) and increased odds of an ATS+ urine screen (aOR 2.80, 95%CI: 1.38-5.66). Sexual violence predicted decreased odds of consistent condom use with non-paying partners (aOR 0.24; 95% CI: 0.10-0.59) and greater odds of a PSA+ vaginal swab (aOR 1.83; 95% CI: 1.13-2.93). Physical and sexual violence are prevalent among Cambodian FESW and associated with subsequent sexual risk and drug use behaviors. Clinical research examining interventions targeting structural and interpersonal factors impacting violence is needed to optimize HIV/AIDS prevention among FESW. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Breeding sex ratio and population size of loggerhead turtles from Southwestern Florida.

Directory of Open Access Journals (Sweden)

Jacob A Lasala

Full Text Available Species that display temperature-dependent sex determination are at risk as a result of increasing global temperatures. For marine turtles, high incubation temperatures can skew sex ratios towards females. There are concerns that temperature increases may result in highly female-biased offspring sex ratios, which would drive a future sex ratio skew. Studying the sex ratios of adults in the ocean is logistically very difficult because individuals are widely distributed and males are inaccessible because they remain in the ocean. Breeding sex ratios (BSR are sought as a functional alternative to study adult sex ratios. One way to examine BSR is to determine the number of males that contribute to nests. Our goal was to evaluate the BSR for loggerhead turtles (Caretta caretta nesting along the eastern Gulf of Mexico in Florida, from 2013-2015, encompassing three nesting seasons. We genotyped 64 nesting females (approximately 28% of all turtles nesting at that time and up to 20 hatchlings from their nests (n = 989 using 7 polymorphic microsatellite markers. We identified multiple paternal contributions in 70% of the nests analyzed and 126 individual males. The breeding sex ratio was approximately 1 female for every 2.5 males. We did not find repeat males in any of our nests. The sex ratio and lack of repeating males was surprising because of female-biased primary sex ratios. We hypothesize that females mate offshore of their nesting beaches as well as en route. We recommend further comparisons of subsequent nesting events and of other beaches as it is imperative to establish baseline breeding sex ratios to understand how growing populations behave before extreme environmental effects are evident.

A heritable component in sex ratio and caste determination in a Cardiocondyla ant

Directory of Open Access Journals (Sweden)

Heinze Jürgen

2009-10-01

Full Text Available Abstract Studies on sex ratios in social insects provide among the most compelling evidence for the importance of kin selection in social evolution. The elegant synthesis of Fisher's sex ratio principle and Hamilton's inclusive fitness theory predicts that colony-level sex ratios vary with the colonies' social and genetic structures. Numerous empirical studies in ants, bees, and wasps have corroborated these predictions. However, the evolutionary optimization of sex ratios requires genetic variation, but one fundamental determinant of sex ratios - the propensity of female larvae to develop into young queens or workers ("queen bias" - is thought to be largely controlled by the environment. Evidence for a genetic influence on sex ratio and queen bias is as yet restricted to a few taxa, in particular hybrids. Because of the very short lifetime of their queens, ants of the genus Cardiocondyla are ideal model systems for the study of complete lifetime reproductive success, queen bias, and sex ratios. We found that lifetime sex ratios of the ant Cardiocondyla kagutsuchi have a heritable component. In experimental single-queen colonies, 22 queens from a genetic lineage with a highly female-biased sex ratio produced significantly more female-biased offspring sex ratios than 16 queens from a lineage with a more male-biased sex ratio (median 91.5% vs. 58.5% female sexuals. Sex ratio variation resulted from different likelihood of female larvae developing into sexuals (median 50% vs. 22.6% female sexuals even when uniformly nursed by workers from another colony. Consistent differences in lifetime sex ratios and queen bias among queens of C. kagutsuchi suggest that heritable, genetic or maternal effects strongly affect caste determination. Such variation might provide the basis for adaptive evolution of queen and worker strategies, though it momentarily constrains the power of workers and queens to optimize caste ratios.

A heritable component in sex ratio and caste determination in a Cardiocondyla ant.

Science.gov (United States)

Frohschammer, Sabine; Heinze, Jürgen

2009-10-28

Studies on sex ratios in social insects provide among the most compelling evidence for the importance of kin selection in social evolution. The elegant synthesis of Fisher's sex ratio principle and Hamilton's inclusive fitness theory predicts that colony-level sex ratios vary with the colonies' social and genetic structures. Numerous empirical studies in ants, bees, and wasps have corroborated these predictions. However, the evolutionary optimization of sex ratios requires genetic variation, but one fundamental determinant of sex ratios - the propensity of female larvae to develop into young queens or workers ("queen bias") - is thought to be largely controlled by the environment. Evidence for a genetic influence on sex ratio and queen bias is as yet restricted to a few taxa, in particular hybrids.Because of the very short lifetime of their queens, ants of the genus Cardiocondyla are ideal model systems for the study of complete lifetime reproductive success, queen bias, and sex ratios. We found that lifetime sex ratios of the ant Cardiocondyla kagutsuchi have a heritable component. In experimental single-queen colonies, 22 queens from a genetic lineage with a highly female-biased sex ratio produced significantly more female-biased offspring sex ratios than 16 queens from a lineage with a more male-biased sex ratio (median 91.5% vs. 58.5% female sexuals). Sex ratio variation resulted from different likelihood of female larvae developing into sexuals (median 50% vs. 22.6% female sexuals) even when uniformly nursed by workers from another colony.Consistent differences in lifetime sex ratios and queen bias among queens of C. kagutsuchi suggest that heritable, genetic or maternal effects strongly affect caste determination. Such variation might provide the basis for adaptive evolution of queen and worker strategies, though it momentarily constrains the power of workers and queens to optimize caste ratios.

Sex-specific effects of mindfulness on romantic partners' cortisol responses to conflict and relations with psychological adjustment.

Science.gov (United States)

Laurent, Heidemarie; Laurent, Sean; Hertz, Robin; Egan-Wright, Dorianne; Granger, Douglas A

2013-12-01

Mindfulness is known to improve individuals' and couples' subjective stress regulation, but little is known about how it impacts hypothalamic-pituitary-adrenal (HPA) axis responses to acute psychosocial stress. The current study tested effects of dispositional mindfulness facets on young adult couples' cortisol responses to a conflict discussion stressor, as well as associations with psychological adjustment. One hundred heterosexual couples completed the five facet mindfulness questionnaire one week before engaging in a conflict discussion task. Each partner provided five saliva samples from pre- to post-conflict, which were assayed for cortisol. Measures of adjustment - depression and anxiety symptoms and global well-being - were also completed at this session. Hierarchical linear modeling of cortisol trajectories revealed sex-specific effects; whereas women's mindfulness (nonreactivity facet) predicted higher conflict stress cortisol levels, men's mindfulness (describing facet) predicted less pronounced cortisol reactivity/recovery curves. These patterns were related to better adjustment-lower depression symptoms for women and greater well-being for men. Implications for sex differences in mindfulness benefits are discussed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sex ratio at birth in India, its relation to birth order, sex of previous children and use of indigenous medicine.

Directory of Open Access Journals (Sweden)

Samiksha Manchanda

Full Text Available OBJECTIVE: Sex-ratio at birth in families with previous girls is worse than those with a boy. Our aim was to prospectively study in a large maternal and child unit sex-ratio against previous birth sex and use of traditional medicines for sex selection. MAIN OUTCOME MEASURES: Sex-ratio among mothers in families with a previous girl and in those with a previous boy, prevalence of indigenous medicine use and sex-ratio in those using medicines for sex selection. RESULTS: Overall there were 806 girls to 1000 boys. The sex-ratio was 720:1000 if there was one previous girl and 178:1000 if there were two previous girls. In second children of families with a previous boy 1017 girls were born per 1000 boys. Sex-ratio in those with one previous girl, who were taking traditional medicines for sex selection, was 928:1000. CONCLUSION: Evidence from the second children clearly shows the sex-ratio is being manipulated by human interventions. More mothers with previous girls tend to use traditional medicines for sex selection, in their subsequent pregnancies. Those taking such medication do not seem to be helped according to expectations. They seem to rely on this method and so are less likely use more definitive methods like sex selective abortions. This is the first such prospective investigation of sex ratio in second children looked at against the sex of previous children. More studies are needed to confirm the findings.

Maternal preconception diet and the sex ratio

NARCIS (Netherlands)

Cramer, J.S.; Lumey, L.H.

2009-01-01

Temporal variations in the sex ratio or the ratio of boys over girls at birth have been widely studied and variously attributed to social changes, conditions of war, and environmental changes. Recently, Mathews, Johnson and Neil (2008) studied the direct evidence of individual pregnancies and

Effects of gamma radiation on development, sterility, fecundity, and sex ratio of Dermanyssus gallinae (DeGeer) (Acari: Dermanyssidae)

International Nuclear Information System (INIS)

Entrekin, D.L.; Oliver, J.H. Jr.; Pound, J.M.

1987-01-01

Protonymphal Dermanyssus gallinae were irradiated with 0.50, 0.75, 1.0, 3.0, and 6.0 krad of gamma radiation and subsequently monitored regarding their developmental, feeding, and mating success. Also, sex ratios of adults treated as protonymphs were recorded as were sex ratios of embryos and F1 adults produced by these adults. Doses up to 1.0 krad did not prevent development of treated protonymphs to the adult stage or stop mating. Three krad reduced the number of treated protonymphs attaining adulthood and 6.0-krad treatment prevented all mites from developing to the adult stage. Egg (embryo) production was normal for mites treated with 0.50 krad, but significantly curtailed by doses of 0.75 krad and greater. Radiation doses used in this study did not appear to affect the normal variable sex ratios observed in untreated mites

Maternal preconception diet and the sex ratio

NARCIS (Netherlands)

Cramer, J.S.; Lumey, L.H.

2010-01-01

Temporal variations in the sex ratio, or the ratio of boys to girls at birth, have been widely studied and variously attributed to social changes, conditions of war, and environmental changes. Recently, Mathews et al. ["You are what your mother eats: Evidence for maternal preconception diet

Sex ratio, gonadal development and fecundity of the grunt ...

African Journals Online (AJOL)

The sex ratio, gonadosomatic index, stages of gonadal development and fecundity of the grunt, Pomadasys jubelini in the New Calabar-Bonny River were investigated. P. jubelini had a sex ratio of 1: 2.1 (male to female). Gonadosomatic index ranged from 0.33 to 7.29% with a mean of 2.89+0.08%. High gonadosomatic ...

Neither Biased Sex Ratio nor Spatial Segregation of the Sexes in the Subtropical Dioecious Tree Eurycorymbus cavaleriei (Sapindaceae)

Institute of Scientific and Technical Information of China (English)

Pu-xin Gao; Ming Kang; Jing Wang; Qi-gang Ye; Hong-wen Huang

2009-01-01

Knowledge of sex ratio and spatial distribution of males and females of dioecious species is both of evolutionary interest and of crucial importance for biological conservation. Eurycorymbus cavaleriei, the only species in the genus Eurycorymbus (Saplndaceae), is a dioecious tree endemic to subtropical montane forest in South China. Sex ratios were investigated in 15 natural populations for the two defined ages (young and old). Spatial distribution of males and females was further studied in six large populations occurring in different habitats (fragmented and continuous). The study revealed a slight trend of malebiased sex ratio in both ages of E. cavaleriei, but sex ratio of most populations (13 out of 15) did not display statistically significant deviation from equality. All of the four significantly male-biased populations in the young class shifted to equality or even female-biased. The Ripley's K analysis of the distribution of males with respect to females suggested that individuals of the opposite sexes were more randomly distributed rather than spatially structured. These results suggest that the male-biased sex ratio in E. cavaleriei may result from the precocity of males and habitat heterogeneity. The sex ratio and the sex spatial distribution pattern are unlikely to constitute a serious threat to the survival of the species.

Sex ratios at birth after induced abortion.

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Urquia, Marcelo L; Moineddin, Rahim; Jha, Prabhat; O'Campo, Patricia J; McKenzie, Kwame; Glazier, Richard H; Henry, David A; Ray, Joel G

2016-06-14

Skewed male:female ratios at birth have been observed among certain immigrant groups. Data on abortion practices that might help to explain these findings are lacking. We examined 1 220 933 births to women with up to 3 consecutive singleton live births between 1993 and 2012 in Ontario. Records of live births, and induced and spontaneous abortions were linked to Canadian immigration records. We determined associations of male:female infant ratios with maternal birthplace, sex of the previous living sibling(s) and prior spontaneous or induced abortions. Male:female infant ratios did not appreciably depart from the normal range among Canadian-born women and most women born outside of Canada, irrespective of the sex of previous children or the characteristics of prior abortions. However, among infants of women who immigrated from India and had previously given birth to 2 girls, the overall male:female ratio was 1.96 (95% confidence interval [CI] 1.75-2.21) for the third live birth. The male:female infant ratio after 2 girls was 1.77 (95% CI 1.26-2.47) times higher if the current birth was preceded by 1 induced abortion, 2.38 (95% CI 1.44-3.94) times higher if preceded by 2 or more induced abortions and 3.88 (95% CI 2.02-7.50) times higher if the induced abortion was performed at 15 weeks or more gestation relative to no preceding abortion. Spontaneous abortions were not associated with male-biased sex ratios in subsequent births. High male:female ratios observed among infants born to women who immigrated from India are associated with induced abortions, especially in the second trimester of pregnancy. © 2016 Canadian Medical Association or its licensors.

Determining sex ratios of turtle hatchlings

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National Oceanic and Atmospheric Administration, Department of Commerce — Previous status assessments of marine turtles have assumed that the natural sex ratio of a marine turtle population is 1:1 (e.g. Conant et al. 2009). However, this...

Live birth sex ratios and father's geographic origins in Jerusalem, 1964-1976.

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Groeger, J; Opler, M; Kleinhaus, K; Perrin, M C; Calderon-Margalit, R; Manor, O; Paltiel, O; Conley, D; Harlap, S; Malaspina, D

2017-05-06

To examine whether ancestry influenced sex ratios of offspring in a birth cohort before parental antenatal sex selection influenced offspring sex. We measured the sex ratio as the percent of males according to countries of birth of paternal and maternal grandfathers in 91,459 live births from 1964 to 1976 in the Jerusalem Perinatal Study. Confidence limits (CI) were computed based on an expected sex ratio of 1.05, which is 51.4% male. Of all live births recorded, 51.4% were male. Relative to Jewish ancestry (51.4% males), significantly more males (1,761) were born to Muslim ancestry (54.5, 95% CI = 52.1-56.8, P = 0.01). Among the former, sex ratios were not significantly associated with paternal or maternal age, education, or offspring's birth order. Consistent with a preference for male offspring, the sex ratio decreased despite increasing numbers of births over the 13-year period. Sex ratios were not affected by maternal or paternal origins in North Africa or Europe. However, the offspring whose paternal grandfathers were born in Western Asia included fewer males than expected (50.7, 50.1-51.3, P = 0.02), whether the father was born abroad (50.7) or in Israel (50.8). This was observed for descendents of paternal grandfathers born in Lebanon (47.6), Turkey (49.9), Yemen & Aden (50.2), Iraq (50.5), Afghanistan (50.5), Syria (50.6), and Cyprus (50.7); but not for those from India (51.5) or Iran (51.9). The West Asian group showed the strongest decline in sex ratios with increasing paternal family size. A decreased sex ratio associated with ancestry in Western Asia is consistent with reduced ability to bear sons by a subset of Jewish men in the Jerusalem cohort. Lower sex ratios may be because of pregnancy stress, which may be higher in this subgroup. Alternatively, a degrading Y chromosome haplogroup or other genetic or epigenetic differences on male germ lines could affect birth ratios, such as differential exposure to an environmental agent, dietary

Live birth sex ratio after in vitro fertilization and embryo transfer in China--an analysis of 121,247 babies from 18 centers.

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Bu, Zhiqin; Chen, Zi-Jiang; Huang, Guoning; Zhang, Hanwang; Wu, Qiongfang; Ma, Yanping; Shi, Juanzi; Xu, Yanwen; Zhang, Songying; Zhang, Cuilian; Zhao, Xiaoming; Zhang, Bo; Huang, Yuanhua; Sun, Zhengyi; Kang, Yuefan; Wu, Riran; Wu, Xueqing; Sun, Haixiang; Sun, Yingpu

2014-01-01

In order to study the impact of procedures of IVF/ICSI technology on sex ratio in China, we conducted this multi-center retrospective study including 121,247 babies born to 93,895 women in China. There were 62,700 male babies and 58,477 female babies, making the sex ratio being 51.8% (Male: Female  = 107:100). In univariate logistic regression analysis, sex ratio was imbalance toward females of 50.3% when ICSI was preformed compared to 47.7% when IVF was used (Pratio in IVF/ICSI babies was significantly higher toward males in transfers of blastocyst (54.9%) and thawed embryo (52.4%) when compared with transfers of cleavage stage embryo (51.4%) and fresh embryo (51.5%), respectively. Multiple delivery was not associated with sex ratio. However, in multivariable logistic regression analysis after controlling for related factors, only ICSI (adjusted OR =  .90, 95%CI: 0.88-0.93; Pratio in IVF/ICSI babies. In conclusion, the live birth sex ratio in IVF/ICSI babies was influenced by the use of ICSI, which may decrease the percentage of male offspring, or the use of blastocyst transfer, which may increase the percentage of male offspring.

Relationship Formation and Stability in Emerging Adulthood: Do Sex Ratios Matter?

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Warner, Tara D.; Manning, Wendy D.; Giordano, Peggy C.; Longmore, Monica A.

2011-01-01

Research links sex ratios with the likelihood of marriage and divorce. However, whether sex ratios similarly influence precursors to marriage (transitions in and out of dating or cohabiting relationships) is unknown. Utilizing data from the Toledo Adolescent Relationships Study and the 2000 U.S. Census, this study assesses whether sex ratios…

Adult sex ratio variation : Implications for breeding system evolution

NARCIS (Netherlands)

Szekely, T.; Weissing, F. J.; Komdeur, J.

Adult sex ratio (ASR) exhibits immense variation in nature, although neither the causes nor the implications of this variation are fully understood. According to theory, the ASR is expected to influence sex roles and breeding systems, as the rarer sex in the population has more potential partners to

Sibling sex ratio of individuals diagnosed with autism spectrum disorder as children

DEFF Research Database (Denmark)

Mouridsen, Svend Erik; Rich, Bente; Isager, Torben

2010-01-01

AIM: To study the sex ratio (proportion of males) in siblings of individuals diagnosed with autism spectrum disorders (ASDs) as children. METHOD: In the current study, we extended previous studies dealing with the androgen theory of autism and examined sex ratios in the siblings of 326 individuals...... the Danish live-birth sex ratio over the same period (0.514, p=0.001). The sibling sex ratio was not associated with the IQ in the autistic probands. INTERPRETATION: Our findings suggest a potential indirect confirmation of the androgen theory of autism....

The potential pitfalls of studying adult sex ratios at aggregate levels in humans.

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Pollet, Thomas V; Stoevenbelt, Andrea H; Kuppens, Toon

2017-09-19

Human adult sex ratios have been studied extensively across the biological and social sciences. While several studies have examined adult sex ratio effects in a multilevel perspective, many studies have focused on effects at an aggregated level only. In this paper, we review some key issues relating to such analyses. We address not only nation-level analyses, but also aggregation at lower levels, to investigate whether these issues extend to lower levels of aggregation. We illustrate these issues with novel databases covering a broad range of variables. Specifically, we discuss distributional issues with aggregated measures of adult sex ratio, significance testing, and statistical non-independence when using aggregate data. Firstly, we show that there are severe distributional issues with national adult sex ratio, such as extreme cases. Secondly, we demonstrate that many 'meaningless' variables are significantly correlated with adult sex ratio (e.g. the max. elevation level correlates with sex ratio at US state level). Finally, we re-examine associations between adult sex ratios and teenage fertility and find no robust evidence for an association at the aggregate level. Our review highlights the potential issues of using aggregate data on adult sex ratios to test hypotheses from an evolutionary perspective in humans.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'. © 2017 The Author(s).

Sex ratios in the Arctic--do man-made chemicals matter?

DEFF Research Database (Denmark)

Bjerregaard, Peter; Chatwood, Susan; Denning, Bryany

2013-01-01

The objective was to analyze the variation of secondary sex ratios across the Arctic and to estimate the time trend. The rationale for this was claims in news media that, in the Arctic, sex ratios have become reduced due to exposure to anthropogenic contaminants in the environment....

Preconception stress and the secondary sex ratio in a population-based preconception cohort.

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Bae, Jisuk; Lynch, Courtney D; Kim, Sungduk; Sundaram, Rajeshwari; Sapra, Katherine J; Buck Louis, Germaine M

2017-03-01

To examine the association between preconception parental stress and the secondary sex ratio, defined as the ratio of males to females at birth. A population-based preconception cohort. Not applicable. A total of 235 couples who were enrolled before conception in Michigan and Texas between 2005 and 2009 and who had a singleton birth during the follow-up period. Couples were interviewed separately at baseline to obtain information on perceived stress (Cohen's Perceived Stress Scale) and lifetime history of physician-diagnosed anxiety and/or mood disorders. Female partners were also trained to collect basal saliva samples for the measurement of salivary stress markers, alpha-amylase and cortisol. None. Birth outcome data including infant sex were collected upon delivery. Modified Poisson regression models were used to estimate the relative risks (RRs) of a male birth for each stress marker. After adjusting for potential confounders, we observed a 76% increase in the risk of fathering a male infant (RR 1.76; 95% confidence interval 1.17-2.65) in men diagnosed with anxiety disorders compared with those who were not diagnosed. When lifetime history of physician-diagnosed anxiety disorders was modeled jointly for the couple, the association was slightly strengthened (RR 2.03; 95% confidence interval 1.46-2.84). This prospective cohort study suggests that paternal lifetime history of physician-diagnosed anxiety disorders may be associated with an increase in the secondary sex ratio, resulting in an excess of male births. Copyright © 2016 American Society for Reproductive Medicine. All rights reserved.

Sex-biased gene flow among elk in the greater Yellowstone ecosystem

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Hand, Brian K.; Chen, Shanyuan; Anderson, Neil; Beja-Pereira, Albano; Cross, Paul C.; Ebinger, Michael R.; Edwards, Hank; Garrott, Robert A.; Kardos, Marty D.; Kauffman, Matthew J.; Landguth, Erin L.; Middleton, Arthur; Scurlock, Brandon M.; White, P.J.; Zager, Pete; Schwartz, Michael K.; Luikart, Gordon

2014-01-01

We quantified patterns of population genetic structure to help understand gene flow among elk populations across the Greater Yellowstone Ecosystem. We sequenced 596 base pairs of the mitochondrial control region of 380 elk from eight populations. Analysis revealed high mitochondrial DNA variation within populations, averaging 13.0 haplotypes with high mean gene diversity (0.85). The genetic differentiation among populations for mitochondrial DNA was relatively high (FST  =  0.161; P  =  0.001) compared to genetic differentiation for nuclear microsatellite data (FST  =  0.002; P  =  0.332), which suggested relatively low female gene flow among populations. The estimated ratio of male to female gene flow (mm/mf  =  46) was among the highest we have seen reported for large mammals. Genetic distance (for mitochondrial DNA pairwise FST) was not significantly correlated with geographic (Euclidean) distance between populations (Mantel's r  =  0.274, P  =  0.168). Large mitochondrial DNA genetic distances (e.g., FST > 0.2) between some of the geographically closest populations (<65 km) suggested behavioral factors and/or landscape features might shape female gene flow patterns. Given the strong sex-biased gene flow, future research and conservation efforts should consider the sexes separately when modeling corridors of gene flow or predicting spread of maternally transmitted diseases. The growing availability of genetic data to compare male vs. female gene flow provides many exciting opportunities to explore the magnitude, causes, and implications of sex-biased gene flow likely to occur in many species.

Economics, cultural transmission, and the dynamics of the sex ratio at birth in China.

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Lipatov, Mikhail; Li, Shuzhuo; Feldman, Marcus W

2008-12-09

In rural China, the ratio of newborn boys to newborn girls [sex ratio at birth (SRB)] has been rising for several decades, to values significantly above its biological norm. This trend has a number of alarming societal consequences, and has attracted the attention of scholars and politicians. The root of the problem lies in a 2,500-year-old culture of son preference. This culture is intricately linked with the economic reality of each couple's life, so that there are financial and psychological repercussions to parents who have no sons. To bring greater clarity and understanding to this issue, we present a quantitative framework that describes the interaction between economics and cultural transmission. We start with an explicit mechanism by which economic incentives can change cultural beliefs of a given individual, and go on to include a mechanism of cultural inheritance from generation to generation. We then show how economic conditions can affect the dynamics of cultural change in an entire society, and may lead to a decrease in the country's sex ratio at birth.

Working Late: Do Workplace Sex Ratios Affect Partnership Formation and Dissolution?

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Svarer, Michael

2007-01-01

In this paper, I analyze the association between workplace sex ratios and partnership formation and dissolution. I find that the risk of dissolution increases with the fraction of coworkers of the opposite sex at both the female and male workplace. On the other hand, workplace sex ratios are not important for the overall transition rate from…

Calcium availability influences litter size and sex ratio in white-footed mice (Peromyscus leucopus.

Directory of Open Access Journals (Sweden)

Christina M Schmidt

Full Text Available The production of offspring typically requires investment of resources derived from both the environment and maternal somatic reserves. As such, the availability of either of these types of resources has the potential to limit the degree to which resources are allocated to reproduction. Theory and empirical studies have argued that mothers modify reproductive performance relative to exogenous resource availability and maternal condition by adjusting size, number or sex of offspring produced. These relationships have classically been defined relative to availability of energy sources; however, in vertebrates, calcium also plays a critical role in offspring production, as a considerable amount of calcium is required to support the development of offspring skeleton(s. We tested whether the availability of calcium influences reproductive output by providing female white-footed mice with a low-calcium or standard diet from reproductive maturity to senescence. We then compared maternal skeletal condition and reproductive output, based on offspring mass, offspring number and litter sex ratio, between dietary treatments. Mothers on the low-calcium diet exhibited diminished skeletal condition at senescence and produced smaller and strongly female-biased litters. We show that skeletal condition and calcium intake can influence sex ratio and reproductive output following general theoretical models of resource partitioning during reproduction.

Sex ratios in the two Germanies: a test of the economic stress hypothesis.

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Catalano, Ralph A

2003-09-01

Literature describing temporal variation in the secondary sex ratio among humans reports an association between population stressors and declines in the odds of male birth. Explanations of this phenomenon draw on reports that stressed females spontaneously abort male more than female fetuses, and that stressed males exhibit reduced sperm motility. This work has led to the argument that population stress induced by a declining economy reduces the human sex ratio. No direct test of this hypothesis appears in the literature. Here, a test is offered based on a comparison of the sex ratio in East and West Germany for the years 1946 to 1999. The theory suggests that the East German sex ratio should be lower in 1991, when East Germany's economy collapsed, than expected from its own history and from the sex ratio in West Germany. The hypothesis is tested using time-series modelling methods. The data support the hypothesis. The sex ratio in East Germany was at its lowest in 1991. This first direct test supports the hypothesis that economic decline reduces the human sex ratio.

Going All In: Unfavorable Sex Ratios Attenuate Choice Diversification.

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Ackerman, Joshua M; Maner, Jon K; Carpenter, Stephanie M

2016-06-01

When faced with risky decisions, people typically choose to diversify their choices by allocating resources across a variety of options and thus avoid putting "all their eggs in one basket." The current research revealed that this tendency is reversed when people face an important cue to mating-related risk: skew in the operational sex ratio, or the ratio of men to women in the local environment. Counter to the typical strategy of choice diversification, findings from four studies demonstrated that the presence of romantically unfavorable sex ratios (those featuring more same-sex than opposite-sex individuals) led heterosexual people to diversify financial resources less and instead concentrate investment in high-risk/high-return options when making lottery, stock-pool, retirement-account, and research-funding decisions. These studies shed light on a key process by which people manage risks to mating success implied by unfavorable interpersonal environments. These choice patterns have important implications for mating behavior as well as other everyday forms of decision making. © The Author(s) 2016.

Genetic architecture of sex determination in fish: Applications to sex ratio control in aquaculture

Directory of Open Access Journals (Sweden)

Paulino eMartínez

2014-09-01

Full Text Available Controlling the sex ratio is essential in finfish farming. A balanced sex ratio is usually good for broodstock management, since it enables to develop appropriate breeding schemes. However, in some species the production of monosex populations is desirable because the existence of sexual dimorphism, primarily in growth or first time of sexual maturation, but also in color or shape, can render one sex more valuable. The knowledge of the genetic architecture of sex determination (SD is convenient for controlling sex ratio and for the implementation of breeding programs. Unlike mammals and birds, which show highly conserved master genes that control a conserved genetic network responsible for gonad differentiation (GD, a huge diversity of SD mechanisms has been reported in fish. Despite theory predictions, more than one gene is in many cases involved in fish SD and genetic differences have been observed in the GD network. Environmental factors also play a relevant role and epigenetic mechanisms are becoming increasingly recognized for the establishment and maintenance of the GD pathways. Although major genetic factors are frequently involved in fish SD, these observations strongly suggest that SD in this group resembles a complex trait. Accordingly, the application of quantitative genetics combined with genomic tools is desirable to address its study and in fact, when applied, it has frequently demonstrated a multigene trait interacting with environmental factors in model and cultured fish species. This scenario has notable implications for aquaculture and, depending upon the species, from chromosome manipulation or environmental control techniques up to classical selection or marker assisted selection programs, are being applied. In this review, we selected four relevant species or fish groups to illustrate this diversity and hence the technologies that can be used by the industry for the control of sex ratio: turbot and European sea bass, two

Adult sex ratio variation: implications for breeding system evolution.

Science.gov (United States)

Székely, T; Weissing, F J; Komdeur, J

2014-08-01

Adult sex ratio (ASR) exhibits immense variation in nature, although neither the causes nor the implications of this variation are fully understood. According to theory, the ASR is expected to influence sex roles and breeding systems, as the rarer sex in the population has more potential partners to mate with than the more common sex. Changes in mate choice, mating systems and parental care suggest that the ASR does influence breeding behaviour, although there is a need for more tests, especially experimental ones. In the context of breeding system evolution, the focus is currently on operational sex ratios (OSRs). We argue that the ASR plays a role of similar importance and urge researchers to study the ASR and the OSR side by side. Finally, we plead for a dynamic view of breeding system evolution with feedbacks between mating, parenting, OSR and ASR on both ecological and evolutionary time scales. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

The impact of sex ratio and economic status on local birth rates

OpenAIRE

Chipman, A.; Morrison, E.

2013-01-01

Human mating and reproductive behaviour can vary depending on various mechanisms, including the local sex ratio. Previous research shows that as sex ratios become female-biased, women from economically deprived areas are less likely to delay reproductive opportunities to wait for a high-investing mate but instead begin their reproductive careers sooner. Here, we show that the local sex ratio also has an impact on female fertility schedules. At young ages, a female-biased ratio is associated w...

Invited commentary: Natural versus unnatural sex ratios--a quandary of modern times.

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Wilcox, Allen J; Baird, Donna D

2011-12-15

The typical dilemma with sex-ratio findings is that when they are real, they aren't interesting, and when they are interesting, they aren't real. In this issue of the Journal, Fernández et al. (Am J Epidemiol. 2011;174(12):1327-1331) describe a deviation of the sex ratio that is apparently both large and real. There was a temporary but distinct spike in the proportion of boys born in Cuba around the time of the collapse of the national economy during the 1990s. Although an excess of boys does not fit the prevailing biologic theory regarding maternal stress and the sex ratio, the data are consistent with results from the Dutch famine (where population-level deprivation was even more extreme). A new quandary arises in the modern era with interpretation of the sex ratio: If the decision to abort a pregnancy is influenced by the sex of the fetus, a change in the behavior of even a small proportion of women could influence the sex ratio at birth. The possible role of sex selection in the Cuban context is discussed.

Adjusting Pulse Amplitude During Transcutaneous Electrical Nerve Stimulation Does Not Provide Greater Hypoalgesia.

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Bergeron-Vézina, Kayla; Filion, Camille; Couture, Chantal; Vallée, Élisabeth; Laroche, Sarah; Léonard, Guillaume

2018-03-01

Transcutaneous electrical nerve stimulation (TENS) is an electrotherapeutic modality commonly used in rehabilitation to relieve pain. Adjusting pulse amplitude (intensity) during TENS treatment has been suggested to overcome nerve habituation. However, it is still unclear if this procedure leads to greater hypoalgesia. The aim of this study was to determine if the hypoalgesic effect of TENS is greater when pulse amplitude is adjusted throughout the TENS treatment session in chronic low-back pain patients. Randomized double-blind crossover study. Recruitment and assessment were conducted at the Clinique universitaire de réadaptation de l'Estrie (CURE) of the Faculty of Medicine and Health Sciences of the Université de Sherbrooke. Twenty-one volunteers with chronic low-back pain were enrolled and completed this investigation. Each patient received two high-frequency TENS treatments on two separate sessions: (1) with adjustment of pulse amplitude and (2) without pulse amplitude adjustment. Pain intensity and unpleasantness were assessed before, during, and after TENS application with a 10 cm visual analog scale. Both TENS conditions (with and without adjustment of intensity) decreased pain intensity and unpleasantness when compared with baseline. No difference was observed between the two stimulation conditions for both pain intensity and unpleasantness. The current results suggest that adjustment of pulse amplitude during TENS application does not provide greater hypoalgesia in individuals with chronic low-back pain. Future studies are needed to confirm these findings in other pain populations.

Adult sex ratios and their implications for cooperative breeding in birds.

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Komdeur, Jan; Székely, Tamás; Long, Xiaoyan; Kingma, Sjouke A

2017-09-19

Cooperative breeding is a form of breeding system where in addition to a core breeding pair, one or more usually non-breeding individuals provide offspring care. Cooperative breeding is widespread in birds, but its origin and maintenance in contemporary populations are debated. Although deviations in adult sex ratio (ASR, the proportion of males in the adult population) have been hypothesized to influence the occurrence of cooperative breeding because of the resulting surplus of one sex and limited availability of breeding partners, this hypothesis has not been tested across a wide range of taxa. By using data from 188 bird species and phylogenetically controlled analyses, we show that cooperatively breeding species have more male-biased ASRs than non-cooperative species. Importantly, ASR predicts helper sex ratio: in species with more male-biased ASR, helper sex ratio is also more male biased. We also show that offspring sex ratios do not predict ASRs, so that the skewed ASRs emerge during the period when individuals aim to obtain a breeding position or later during adulthood. In line with this result, we found that ASR (among both cooperatively and non-cooperatively breeding species) is inversely related to sex bias in dispersal distance, suggesting that the cost of dispersal is more severe for the further-dispersing sex. As females usually disperse further in birds, this explains the generally male-biased ASR, and in combination with benefits of philopatry for males, this probably explains why ASR is more biased in cooperatively breeding species. Taken together, our results suggest that a sex bias in helping in cooperatively breeding species relates to biased ASRs. We propose that this relationship is driven by sex-specific costs and benefits of dispersal and helping, as well as other demographic factors. Future phylogenetic comparative and experimental work is needed to establish how this relationship emerges.This article is part of the themed issue 'Adult sex

Phenotypic plasticity in response to the social environment: effects of density and sex ratio on mating behaviour following ecotype divergence.

Directory of Open Access Journals (Sweden)

Kristina Karlsson

Full Text Available The ability to express phenotypically plastic responses to environmental cues might be adaptive in changing environments. We studied phenotypic plasticity in mating behaviour as a response to population density and adult sex ratio in a freshwater isopod (Asellus aquaticus. A. aquaticus has recently diverged into two distinct ecotypes, inhabiting different lake habitats (reed Phragmites australis and stonewort Chara tomentosa, respectively. In field surveys, we found that these habitats differ markedly in isopod population densities and adult sex ratios. These spatially and temporally demographic differences are likely to affect mating behaviour. We performed behavioural experiments using animals from both the ancestral ecotype ("reed" isopods and from the novel ecotype ("stonewort" isopods population. We found that neither ecotype adjusted their behaviour in response to population density. However, the reed ecotype had a higher intrinsic mating propensity across densities. In contrast to the effects of density, we found ecotype differences in plasticity in response to sex ratio. The stonewort ecotype show pronounced phenotypic plasticity in mating propensity to adult sex ratio, whereas the reed ecotype showed a more canalised behaviour with respect to this demographic factor. We suggest that the lower overall mating propensity and the phenotypic plasticity in response to sex ratio have evolved in the novel stonewort ecotype following invasion of the novel habitat. Plasticity in mating behaviour may in turn have effects on the direction and intensity of sexual selection in the stonewort habitat, which may fuel further ecotype divergence.

India's Distorted Sex Ratio: Dire Consequences for Girls.

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Roberts, Lisa R; Montgomery, Susanne B

2016-01-01

Female gender discrimination related to cultural preference for males is a common global problem, especially in Asian countries. Numerous laws intended to prevent discrimination on the basis of gender have been passed in India, yet the distorted female-to-male sex ratio seems to show worsening tendencies. Using detailed, two-year longitudinal chart abstraction data about delivery records of a private mission hospital in rural India, we explored if hospital birth ratio data differed in comparison to regional data, and what demographic and contextual variables may have influenced these outcomes. Using quantitative chart abstraction and qualitative contextual data, study results showed the female-to-male ratio was lower than the reported state ratio at birth. In the context of India's patriarchal structure, with its strong son preference, women are under tremendous pressure or coerced to access community-based, sex-selective identification and female fetus abortion. Nurses may be key to turning the tide.

Differences in Psychological Sex, Adjustment, and Familial Influences Among Homosexual and Nonhomosexual Populations

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Townes, Brenda D.; And Others

1976-01-01

This study investigates differences in psychological sex, present and past adjustment, and parental influences among homosexual cross-dressers, homosexual non-cross-dressers, applicants for sex change surgery, and heterosexuals. Homosexual non-cross-dressers and heterosexual groups had the most masculine gender role, with the sex change group…

Sex Ratio Bias Leads to the Evolution of Sex Role Reversal in Honey Locust Beetles.

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Fritzsche, Karoline; Booksmythe, Isobel; Arnqvist, Göran

2016-09-26

The reversal of conventional sex roles was enigmatic to Darwin, who suggested that it may evolve when sex ratios are female biased [1]. Here we present direct evidence confirming Darwin's hypothesis. We investigated mating system evolution in a sex-role-reversed beetle (Megabruchidius dorsalis) using experimental evolution under manipulated sex ratios and food regimes. In female-biased populations, where reproductive competition among females was intensified, females evolved to be more attractive and the sex roles became more reversed. Interestingly, female-specific mating behavior evolved more rapidly than male-specific mating behavior. We show that sexual selection due to reproductive competition can be strong in females and can target much the same traits as in males of species with conventional mating systems. Our study highlights two central points: the role of ecology in directing sexual selection and the role that females play in mating system evolution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Abnormal sex ratios in human populations: causes and consequences.

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Hesketh, Therese; Xing, Zhu Wei

2006-09-05

In the absence of manipulation, both the sex ratio at birth and the population sex ratio are remarkably constant in human populations. Small alterations do occur naturally; for example, a small excess of male births has been reported to occur during and after war. The tradition of son preference, however, has distorted these natural sex ratios in large parts of Asia and North Africa. This son preference is manifest in sex-selective abortion and in discrimination in care practices for girls, both of which lead to higher female mortality. Differential gender mortality has been a documented problem for decades and led to reports in the early 1990s of 100 million "missing women" across the developing world. Since that time, improved health care and conditions for women have resulted in reductions in female mortality, but these advances have now been offset by a huge increase in the use of sex-selective abortion, which became available in the mid-1980s. Largely as a result of this practice, there are now an estimated 80 million missing females in India and China alone. The large cohorts of "surplus" males now reaching adulthood are predominantly of low socioeconomic class, and concerns have been expressed that their lack of marriageability, and consequent marginalization in society, may lead to antisocial behavior and violence, threatening societal stability and security. Measures to reduce sex selection must include strict enforcement of existing legislation, the ensuring of equal rights for women, and public awareness campaigns about the dangers of gender imbalance.

The financial consequences of too many men: sex ratio effects on saving, borrowing, and spending.

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Griskevicius, Vladas; Tybur, Joshua M; Ackerman, Joshua M; Delton, Andrew W; Robertson, Theresa E; White, Andrew E

2012-01-01

The ratio of males to females in a population is an important factor in determining behavior in animals. We propose that sex ratio also has pervasive effects in humans, such as by influencing economic decisions. Using both historical data and experiments, we examined how sex ratio influences saving, borrowing, and spending in the United States. Findings show that male-biased sex ratios (an abundance of men) lead men to discount the future and desire immediate rewards. Male-biased sex ratios decreased men's desire to save for the future and increased their willingness to incur debt for immediate expenditures. Sex ratio appears to influence behavior by increasing the intensity of same-sex competition for mates. Accordingly, a scarcity of women led people to expect men to spend more money during courtship, such as by paying more for engagement rings. These findings demonstrate experimentally that sex ratio influences human decision making in ways consistent with evolutionary biological theory. Implications for sex ratio effects across cultures are discussed.

The evolution of sex roles in birds is related to adult sex ratio.

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

2013-01-01

Sex-role reversal represents a formidable challenge for evolutionary biologists, since it is not clear which ecological, life-history or social factors facilitated conventional sex roles (female care and male-male competition for mates) to be reversed (male care and female-female competition). Classic theories suggested ecological or life-history predictors of role reversal, but most studies failed to support these hypotheses. Recent theory however predicts that sex-role reversal should be driven by male-biased adult sex ratio (ASR). Here we test this prediction for the first time using phylogenetic comparative analyses. Consistent with theory, both mating system and parental care are strongly related to ASR in shorebirds: conventional sex roles are exhibited by species with female-biased ASR, whereas sex-role reversal is associated with male-biased ASR. These results suggest that social environment has a strong influence on breeding systems and therefore revealing the causes of ASR variation in wild populations is essential for understanding sex role evolution.

Sex-Specific Arrival Times on the Breeding Grounds: Hybridizing Migratory Skuas Provide Empirical Support for the Role of Sex Ratios.

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Lisovski, Simeon; Fröhlich, Anne; von Tersch, Matthew; Klaassen, Marcel; Peter, Hans-Ulrich; Ritz, Markus S

2016-04-01

In migratory animals, protandry (earlier arrival of males on the breeding grounds) prevails over protogyny (females preceding males). In theory, sex differences in timing of arrival should be driven by the operational sex ratio, shifting toward protogyny in female-biased populations. However, empirical support for this hypothesis is, to date, lacking. To test this hypothesis, we analyzed arrival data from three populations of the long-distance migratory south polar skua (Catharacta maccormicki). These populations differed in their operational sex ratio caused by the unidirectional hybridization of male south polar skuas with female brown skuas (Catharacta antarctica lonnbergi). We found that arrival times were protandrous in allopatry, shifting toward protogyny in female-biased populations when breeding in sympatry. This unique observation is consistent with theoretical predictions that sex-specific arrival times should be influenced by sex ratio and that protogyny should be observed in populations with female-biased operational sex ratio.

Territory Quality and Plumage Morph Predict Offspring Sex Ratio Variation in a Raptor.

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Nayden Chakarov

Full Text Available Parents may adapt their offspring sex ratio in response to their own phenotype and environmental conditions. The most significant causes for adaptive sex-ratio variation might express themselves as different distributions of fitness components between sexes along a given variable. Several causes for differential sex allocation in raptors with reversed sexual size dimorphism have been suggested. We search for correlates of fledgling sex in an extensive dataset on common buzzards Buteo buteo, a long-lived bird of prey. Larger female offspring could be more resource-demanding and starvation-prone and thus the costly sex. Prominent factors such as brood size and laying date did not predict nestling sex. Nonetheless, lifetime sex ratio (LSR, potentially indicative of individual sex allocation constraints and overall nestling sex were explained by territory quality with more females being produced in better territories. Additionally, parental plumage morphs and the interaction of morph and prey abundance tended to explain LSR and nestling sex, indicating local adaptation of sex allocation However, in a limited census of nestling mortality, not females but males tended to die more frequently in prey-rich years. Also, although females could have potentially longer reproductive careers, a subset of our data encompassing full individual life histories showed that longevity and lifetime reproductive success were similarly distributed between the sexes. Thus, a basis for adaptive sex allocation in this population remains elusive. Overall, in common buzzards most major determinants of reproductive success appeared to have no effect on sex ratio but sex allocation may be adapted to local conditions in morph-specific patterns.

High fat diet prevents over-crowding induced decrease of sex ratio in mice.

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Madhukar Shivajirao Dama

Full Text Available Adaptive theory predicts that mothers would be advantaged by adjusting the sex ratio of their offspring in relation to their offspring's future reproductive success. In the present study, we tested the effect of housing mice under crowded condition on the sex ratio and whether the fat content of the diet has any influence on the outcome of pregnancies. Three-week-old mice were placed on the control diet (NFD for 3 weeks. Thereafter the mice were allotted randomly to two groups of 7 cages each with 4, 6, 8, 10, 12, 14, and 16 mice in every cage to create increasing crowding gradient and fed either NFD or high fat diet (HFD. After 4 weeks, dams were bred and outcomes of pregnancy were analyzed. The average dam body weight (DBW at conception, litter size (LS and SR were significantly higher in HFD fed dams. Further, male biased litters declined with increasing crowding in NFD group but not in HFD. The LS and SR in NFD declined significantly with increasing crowding, whereas only LS was reduced in HFD group. We conclude that female mice housed under overcrowding conditions shift offspring SR in favor of daughters in consistent with the TW hypothesis and high fat diet reduces this influence of overcrowding.

NDVI saturation adjustment: a new approach for improving cropland performance estimates in the Greater Platte River Basin, USA

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Gu, Yingxin; Wylie, Bruce K.; Howard, Daniel M.; Phuyal, Khem P.; Ji, Lei

2013-01-01

In this study, we developed a new approach that adjusted normalized difference vegetation index (NDVI) pixel values that were near saturation to better characterize the cropland performance (CP) in the Greater Platte River Basin (GPRB), USA. The relationship between NDVI and the ratio vegetation index (RVI) at high NDVI values was investigated, and an empirical equation for estimating saturation-adjusted NDVI (NDVIsat_adjust) based on RVI was developed. A 10-year (2000–2009) NDVIsat_adjust data set was developed using 250-m 7-day composite historical eMODIS (expedited Moderate Resolution Imaging Spectroradiometer) NDVI data. The growing season averaged NDVI (GSN), which is a proxy for ecosystem performance, was estimated and long-term NDVI non-saturation- and saturation-adjusted cropland performance (CPnon_sat_adjust, CPsat_adjust) maps were produced over the GPRB. The final CP maps were validated using National Agricultural Statistics Service (NASS) crop yield data. The relationship between CPsat_adjust and the NASS average corn yield data (r = 0.78, 113 samples) is stronger than the relationship between CPnon_sat_adjust and the NASS average corn yield data (r = 0.67, 113 samples), indicating that the new CPsat_adjust map reduces the NDVI saturation effects and is in good agreement with the corn yield ground observations. Results demonstrate that the NDVI saturation adjustment approach improves the quality of the original GSN map and better depicts the actual vegetation conditions of the GPRB cropland systems.

Live birth sex ratios and father’s geographic origins in Jerusalem, 1964–1976

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Groeger, J; Opler, M; Kleinhaus, K; Perrin, MC; Calderon-Margalit, R; Manor, O; Paltiel, O; Conley, D; Harlap, S; Malaspina, D

2016-01-01

Objective To examine whether ancestry influenced sex ratios of offspring in a birth cohort before parental antenatal sex selection influenced offspring sex. Methods We measured the sex ratio as the percent of males according to countries of birth of paternal and maternal grandfathers in 91,459 live births from 1964 to 1976 in the Jerusalem Perinatal Study. Confidence limits (CI) were computed based on an expected sex ratio of 1.05, which is 51.4% male. Results Of all live births recorded, 51.4% were male. Relative to Jewish ancestry (51.4% males), significantly more males (1,761) were born to Muslim ancestry (54.5, 95% CI=52.1–56.8, p=.01). Among the former, sex ratios were not significantly associated with paternal or maternal age, education, or offspring’s birth order. Consistent with a preference for male offspring, the sex ratio decreased despite increasing numbers of births over the 13-year period. Sex ratios were not affected by maternal or paternal origins in North Africa or Europe. However, the offspring whose paternal grandfathers were born in Western Asia included fewer males than expected (50.7, 50.1–51.3, p=.02), whether the father was born abroad (50.7) or in Israel (50.8). This was observed for descendents of paternal grandfathers born in Lebanon (47.6), Turkey (49.9), Yemen & Aden (50.2), Iraq (50.5), Afghanistan (50.5), Syria (50.6), and Cyprus (50.7); but not for those from India (51.5) or Iran (51.9). The West Asian group showed the strongest decline in sex ratios with increasing paternal family size. Conclusions A decreased sex ratio associated with ancestry in Western Asia is consistent with reduced ability to bear sons by a subset of Jewish men in the Jerusalem cohort. Lower sex ratios may be due to pregnancy stress, which may be higher in this subgroup. Alternatively, a degrading Y chromosome haplogroup or other genetic or epigenetic differences on male germ lines could affect birth ratios, such as differential exposure to an

The male handicap: male-biased mortality explains skewed sex ratios in brown trout embryos.

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Morán, P; Labbé, L; Garcia de Leaniz, C

2016-12-01

Juvenile sex ratios are often assumed to be equal for many species with genetic sex determination, but this has rarely been tested in fish embryos due to their small size and absence of sex-specific markers. We artificially crossed three populations of brown trout and used a recently developed genetic marker for sexing the offspring of both pure and hybrid crosses. Sex ratios (SR = proportion of males) varied widely one month after hatching ranging from 0.15 to 0.90 (mean = 0.39 ± 0.03). Families with high survival tended to produce balanced or male-biased sex ratios, but SR was significantly female-biased when survival was low, suggesting that males sustain higher mortality during development. No difference in SR was found between pure and hybrid families, but the existence of sire × dam interactions suggests that genetic incompatibility may play a role in determining sex ratios. Our findings have implications for animal breeding and conservation because skewed sex ratios will tend to reduce effective population size and bias selection estimates. © 2016 The Authors.

Different sex ratios of children born to Indian and Pakistani immigrants in Norway

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Brekke Torkel

2010-08-01

Full Text Available Abstract Background A low female-to-male ratio has been observed in different Asian countries, but this phenomenon has not been well studied among immigrants living in Western societies. In this study, we investigated whether a low female-to-male ratio exists among Indian and Pakistani immigrants living in Norway. In particular, we investigated whether the determination of sex via ultrasound examination, a common obstetric procedure that has been used in Norway since the early 1980 s, has influenced the female-to-male ratio among children born to parents of Indian or Pakistani origin. Methods We performed a retrospective cohort study of live births in mothers of Indian (n = 1597 and Pakistani (n = 5617 origin. Data were obtained from "Statistics Norway" and the female-to-male (F/M sex ratio was evaluated among 21,325 children born, in increasing birth order, during three stratified periods (i.e., 1969-1986, 1987-1996, and 1997-2005. Results A significant low female-to-male sex ratio was observed among children in the third and fourth birth order (sex ratio 65; 95% CI 51-80 from mothers of Indian origin who gave birth after 1987. Sex ratios did not deviate from the expected natural variation in the Indian cohort from 1969 to 1986, and remained stable in the Pakistani cohort during the entire study period. However, the female-to-male sex ratio seemed less skewed in recent years (i.e., 1997-2005. Conclusion Significant differences were observed in the sex ratio of children born to mothers of Indian origin compared with children born to mothers of Pakistani origin. A skewed number of female births among higher birth orders (i.e., third or later may partly reflect an increase in sex-selective abortion among mothers of Indian origin, although the numbers are too small to draw firm conclusions. Further research is needed to explain the observed differences in the female-to-male ratio among members of these ethnic groups who reside in Norway.

The sex ratio distortion in the human head louse is conserved over time

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Biliński Szczepan M

2004-05-01

Full Text Available Abstract Background At the turn of the 19th century the first observations of a female-biased sex ratio in broods and populations of the head louse, Pediculus humanus capitis, had been reported. A study by Buxton in 1940 on the sex ratio of lice on prisoners in Ceylon is still today the subject of reanalyses. This sex ratio distortion had been detected in ten different countries. In the last sixty years no new data have been collected, especially on scalp infestations under economically and socially more developed conditions. Results Here we report a female bias of head lice in a survey of 480 school children in Argentina. This bias is independent of the intensity of the pediculosis, which makes local mate competition highly unlikely as the source of the aberrant sex ratio; however, other possible adaptive mechanisms cannot be discounted. These lice as well as lice from pupils in Britain were carrying several strains of the endosymbiotic bacterium Wolbachia pipientis, one of the most wide spread intracellular sex ratio distorters. Similar Wolbachia strains are also present in the pig louse, Haematopinus suis, suggesting that this endosymbiont might have a marked influence on the biology of the whole order. The presence of a related obligate nutritional bacterium in lice prevents the investigation of a causal link between sex ratio and endosymbionts. Conclusions Regardless of its origin, this sex ratio distortion in head lice that has been reported world wide, is stable over time and is a remarkable deviation from the stability of frequency-dependent selection of Fisher's sex ratio. A female bias first reported in 1898 is still present over a hundred years and a thousand generations later.

Manipulation of primary sex ratio in birds: lessons from the homing pigeon (Columba livia domestica).

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Goerlich-Jansson, Vivian C; Müller, Martina S; Groothuis, Ton G G

2013-12-01

Across various animal taxa not only the secondary sex ratio but also the primary sex ratio (at conception) shows significant deviations from the expected equal proportions of sons and daughters. Birds are especially intriguing to study this phenomenon as avian females are the heterogametic sex (ZW); therefore sex determination might be under direct control of the mother. Avian sex ratios vary in relation to environmental or maternal condition, which can also affect the production of maternal steroids that in turn are involved in reproduction and accumulate in the developing follicle before meiosis. As the proximate mechanisms underlying biased primary sex ratio are largely elusive, we explored how, and to what extent, maternal steroid hormones may be involved in affecting primary or secondary sex ratio in clutches of various species of pigeons. First we demonstrated a clear case of seasonal change in sex ratio in first eggs both in the Rock Pigeon (Columba livia) and in a related species, the Wood Pigeon (Columba palumbus), both producing clutches of two eggs. In the Homing Pigeon (Columba livia domestica), domesticated from the Rock Pigeon, testosterone treatment of breeding females induced a clear male bias, while corticosterone induced a female bias in first eggs and we argue that this is in line with sex allocation theory. We next analyzed treatment effects on follicle formation, yolk mass, and yolk hormones, the latter both pre- and post-ovulatory, in order to test a diversity of potential mechanisms related to both primary and secondary sex ratio manipulation. We conclude that maternal plasma hormone levels may affect several pre-ovulatory mechanisms affecting primary sex ratio, whereas egg hormones are probably involved in secondary sex ratio manipulation only.

Does predation control adult sex ratios and longevities in marine pelagic copepods?

DEFF Research Database (Denmark)

Hirst, A.G.; Bonnet, D.; Conway, D.V.P.

2010-01-01

We assess the causes of adult sex ratio skew in marine pelagic copepods by examining changes in these ratios between the juveniles and adults, sexual differences in juvenile stage durations, and mortality rates of adults in the field and laboratory (when free from predators). In the field, late...... copepodite stages (CIV and CV) commonly have sex ratios that are either not significantly different from equity (1 : 1), or slightly male biased. By contrast, in adults, these ratios are commonly significantly biased toward female dominance. Sex ratio skews are therefore primarily attributable to processes...... in adults. Members of the non-Diaptomoidea have especially skewed adult ratios; in the members Oithonidae and Clausocalanidae this is not generated from differences between male and female adult physiological longevity (i.e., laboratory longevity when free of predators). In the genera Acartia, Oithona...

Sex ratio at birth and mortality rates are negatively related in humans.

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Madhukar Shivajirao Dama

Full Text Available Evolutionary theory posits that resource availability and parental investment ability could signal offspring sex selection, in order to maximize reproductive returns. Non-human studies have provided evidence for this phenomenon, and maternal condition around the time of conception has been identified as most important factor that influence offspring sex selection. However, studies on humans have reported inconsistent results, mostly due to use of disparate measures as indicators of maternal condition. In the present study, the cross-cultural differences in human natal sex ratio were analyzed with respect to indirect measures of condition namely, life expectancy and mortality rate. Multiple regression modeling suggested that mortality rates have distinct predictive power independent of cross-cultural differences in fertility, wealth and latitude that were earlier shown to predict sex ratio at birth. These findings suggest that sex ratio variation in humans may relate to differences in parental and environmental conditions.

Gender Inequality and the Sex Ratio in Three Emerging Economies

OpenAIRE

Prabir C. Bhattacharya

2012-01-01

The aim of this paper is to study inequality and deprivations as reflected in the human sex ratio (commonly defined as the number of males per 100 females). The particular focus is on three emerging economies, viz., Russia, India and China. The paper compares and contrasts the experiences of these countries and discusses policy issues. It is noted that while the feminist perspective on the issues surrounding the sex ratio is important, it would be wrong to view these issues always or exclusiv...

India’s Distorted Sex Ratio: Dire Consequences for Girls

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Roberts, Lisa R.; Montgomery, Susanne B.

2017-01-01

Female gender discrimination related to cultural preference for males is a common global problem, especially in Asian countries. Numerous laws intended to prevent discrimination on the basis of gender have been passed in India, yet the distorted female-to-male sex ratio seems to show worsening tendencies. Using detailed, two-year longitudinal chart abstraction data about delivery records of a private mission hospital in rural India, we explored if hospital birth ratio data differed in comparison to regional data, and what demographic and contextual variables may have influenced these outcomes. Using quantitative chart abstraction and qualitative contextual data, study results showed the female-to-male ratio was lower than the reported state ratio at birth. In the context of India’s patriarchal structure, with its strong son preference, women are under tremendous pressure or coerced to access community-based, sex-selective identification and female fetus abortion. Nurses may be key to turning the tide. PMID:28286369

Female-biased sex ratios in marine pelagic copepods: Comment on Gusmao et al. (2013)

DEFF Research Database (Denmark)

Hirst, Andrew G.; Bonnet, D; Conway, DVP

2013-01-01

Gusmao et al. (2013; Mar Ecol Prog Ser 482:279-298) review causes of sex ratio skew in pelagic copepods and in doing so repeatedly dispute the paper of Hirst et al. (2010) ‘Does predation control adult sex ratios and longevities in marine pelagic copepods?’ Here we respond to some important error...... in their citation of our paper and briefly highlight where future work is needed in order to attribute the causes of strong sex ratio skew seen in some copepod families......Gusmao et al. (2013; Mar Ecol Prog Ser 482:279-298) review causes of sex ratio skew in pelagic copepods and in doing so repeatedly dispute the paper of Hirst et al. (2010) ‘Does predation control adult sex ratios and longevities in marine pelagic copepods?’ Here we respond to some important errors...

Increased sex ratio in Russia and Cuba after Chernobyl: a radiological hypothesis.

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Scherb, Hagen; Kusmierz, Ralf; Voigt, Kristina

2013-08-15

The ratio of male to female offspring at birth may be a simple and non-invasive way to monitor the reproductive health of a population. Except in societies where selective abortion skews the sex ratio, approximately 105 boys are born for every 100 girls. Generally, the human sex ratio at birth is remarkably constant in large populations. After the Chernobyl nuclear power plant accident in April 1986, a long lasting significant elevation in the sex ratio has been found in Russia, i.e. more boys or fewer girls compared to expectation were born. Recently, also for Cuba an escalated sex ratio from 1987 onward has been documented and discussed in the scientific literature. By the end of the eighties of the last century in Cuba as much as about 60% of the food imports were provided by the former Soviet Union. Due to its difficult economic situation, Cuba had neither the necessary insight nor the political strength to circumvent the detrimental genetic effects of imported radioactively contaminated foodstuffs after Chernobyl. We propose that the long term stable sex ratio increase in Cuba is essentially due to ionizing radiation. A synoptic trend analysis of Russian and Cuban annual sex ratios discloses upward jumps in 1987. The estimated jump height from 1986 to 1987 in Russia measures 0.51% with a 95% confidence interval (0.28, 0.75), p value Cuba the estimated jump height measures 2.99% (2.39, 3.60), p value Cuba and by radiological analyses of remains in Cuba for Cs-137 and Sr-90. If the evidence for the hypothesis is strengthened, there is potential to learn about genetic radiation risks and to prevent similar effects in present and future exposure situations.

Change in schistosome sex ratio under the influence of a biotic environmental-related factor.

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Moné, H

1997-04-01

Schistosoma mansoni is a dioecious trematode responsible for intestinal schistosomiasis in man. The sex ratio was determined for S. mansoni adults derived from cercariae obtained from infected Biomphalaria glabrata maintained in the presence of the nonvector molluse. Marisa cornuarietis. The presence of M. cornuarietis is responsible for enhanced growth of B. glabrata and for a change in the sex ratio of the schistosome, which becomes more male-biased as compared to control snails maintained in aquaria lacking M. cornuarietis. This is the first time the presence of another species in the environment has been shown to influence schistosome sex ratios. Two nonexclusive hypotheses are proposed to explain this variation in the sex ratio: sexual competition between male and female sporocysts; and sex reversal.

Pre-ovulation control of hatchling sex ratio in the Seychelles warbler

NARCIS (Netherlands)

Komdeur, J; Magrath, MJL; Krackow, S

2002-01-01

Females of some bird species have a high degree of control over the sex ratio of their offspring at laying. Although several mechanisms have been put forward to explain how females might control the sex of their eggs, virtually nothing is known. As females are the heterogametic sex in birds,

SEX ALLOCATION ADJUSTMENT TO MATING GROUP SIZE IN A SIMULTANEOUS HERMAPHRODITE

NARCIS (Netherlands)

Janicke, Tim; Marie-Orleach, Lucas; De Mulder, Katrien; Berezikov, Eugene; Ladurner, Peter; Vizoso, Dita B.; Schaerer, Lukas

2013-01-01

Sex allocation theory is considered as a touchstone of evolutionary biology, providing some of the best supported examples for Darwinian adaptation. In particular, Hamilton's local mate competition theory has been shown to generate precise predictions for extraordinary sex ratios observed in many

Offspring sex ratio is related to paternal train elaboration and yolk corticosterone in peafowl.

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Pike, Thomas W; Petrie, Marion

2005-06-22

Several recent experimental studies have provided strong evidence for the ability of birds to manipulate the sex ratio of their offspring prior to laying. Using a captive population of peafowl (Pavo cristatus), we tested experimentally the effects of paternal attractiveness on offspring sex ratio, and related sex ratio deviations to egg-yolk concentrations of testosterone, 17beta-estradiol and corticosterone. When females were mated to males whose attractiveness had been experimentally reduced by removing prominent eyespot feathers from their trains, they produced significantly more female offspring, had significantly higher yolk corticosterone concentrations and tended to have lower levels of yolk testosterone than when mated to the same males with their full complement of feathers. Concentrations of 17beta-estradiol did not vary consistently with sex ratio biases. These findings add to the small number of studies providing experimental evidence that female birds can control the primary sex ratio of their offspring in response to paternal attractiveness, and highlight the possibility that corticosterone and perhaps testosterone are involved in the sex manipulation process in birds.

The impact of sex ratio and economic status on local birth rates.

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Chipman, A; Morrison, E

2013-04-23

Human mating and reproductive behaviour can vary depending on various mechanisms, including the local sex ratio. Previous research shows that as sex ratios become female-biased, women from economically deprived areas are less likely to delay reproductive opportunities to wait for a high-investing mate but instead begin their reproductive careers sooner. Here, we show that the local sex ratio also has an impact on female fertility schedules. At young ages, a female-biased ratio is associated with higher birth rates in the poorest areas, whereas the opposite is true for the richest areas. At older ages, a female-biased ratio is associated with higher birth rates in the richest, but not the poorest areas. These patterns suggest that female-female competition encourages poorer women to adopt a fast life-history strategy and give birth early, and richer women to adopt a slow life-history strategy and delay reproduction.

Gender Identity and Adjustment: Understanding the Impact of Individual and Normative Differences in Sex Typing

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Lurye, Leah E.; Zosuls, Kristina M.; Ruble, Diane N.

2009-01-01

The relationship among gender identity, sex typing, and adjustment has attracted the attention of social and developmental psychologists for many years. However, they have explored this issue with different assumptions and different approaches. Generally the approaches differ regarding whether sex typing is considered adaptive versus maladaptive, measured as an individual or normative difference, and whether gender identity is regarded as a unidimensional or multidimensional construct. In this chapter, we consider both perspectives and suggest that the developmental timing and degree of sex typing, as well as the multidimensionality of gender identity, be considered when examining their relationship to adjustment. PMID:18521861

Sex ratio distribution and fecundity of the claroteid catfish Clarotes ...

African Journals Online (AJOL)

Sex ratio distribution and fecundity of Clarotes laticeps were investigated between January 2010 and December 2012 in the lower River Niger. Samples were collected every two weeks for 36 months from six sampling sites, using a combination of baited longlines, gill nets and cast nets. Sexes of captured specimens were ...

Socioeconomic status influences sex ratios in a Chinese rural population.

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Luo, Liqun; Ding, Rui; Gao, Xiali; Sun, Jingjing; Zhao, Wei

2017-01-01

According to the logic of the Trivers-Willard hypothesis, in a human population, if socioeconomic status is transmitted across generations to some extent, and if sons of high-status parents tend to have higher reproductive success than daughters, while daughters of low-status parents tend to have higher reproductive success than sons, then we should expect that offspring sex ratio is positively associated with socioeconomic status. This study examines whether the assumptions and prediction of this hypothesis apply to a rural population in northern China. Results show that (1) current family socioeconomic status is positively related to family head's father's socioeconomic status in around 1950, (2) low-status family heads have more grandchildren through their daughters than their sons, whereas high- or middle-status family heads have more grandchildren through sons, and (3) as family heads' status increases, they tend to produce a higher offspring sex ratio. Therefore, the assumptions and prediction of the hypothesis are met in the study population. These results are discussed in reference to past studies on sex ratio manipulation among humans.

Strong but variable associations between social dominance and clutch sex ratio in a colonial corvid

NARCIS (Netherlands)

Salomons, H. M.; Dijkstra, C.; Verhulst, S.

2008-01-01

We studied primary sex ratio of clutches in relation to social dominance for 6 years in a colony of free-living jackdaws, a small corvid. Social dominance was strongly associated with clutch sex ratio, with the difference in clutch sex ratio between the most and least dominant pairs being 30-40%. To

Phenotypic sex ratios of Atriplex canescens shrubs in relation to cattle browsing

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Andres F. Cibils; David M. Swift; Richard H. Hart

2001-01-01

Previous studies conducted at our research site on the shortgrass steppe in Colorado showed that phenotypic sex ratios of tetraploid fourwing saltbush (Atriplex canescens Pursh [Nutt]) shrubs were less female biased in grazed pastures than in adjacent exclosures. The potential effects of cattle browsing on shrub sex ratios were studied both in the field and in a...

Skewed Marriage Markets and Sex Ratios of Finnish People in their Twenties

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Lassi Lainiala

2014-03-01

Full Text Available This article studies variation in regional sex ratios in Finland and outlines potential implications of the skewed sex ratios for family formation patterns. Difficulties in finding a suitable partner are typically mentioned as one of the most important reasons for remaining childless, and we explore if this reason is apparent structurally at the regional macro level. We found significant variation in sex ratios in age-groups 18–30 at the regional and sub-regional levels. Of the whole 20–29-year old population in Finland, almost 50 percent live in sub-region areas with a male surplus. As expected, a higher proportion of men compared to women appears to increase fertility of women in younger age groups. Contrary to expectations, high male-female ratios were not related to higher proportion of women living with a partner

Increased sex ratio in Russia and Cuba after Chernobyl: a radiological hypothesis

Science.gov (United States)

2013-01-01

Background The ratio of male to female offspring at birth may be a simple and non-invasive way to monitor the reproductive health of a population. Except in societies where selective abortion skews the sex ratio, approximately 105 boys are born for every 100 girls. Generally, the human sex ratio at birth is remarkably constant in large populations. After the Chernobyl nuclear power plant accident in April 1986, a long lasting significant elevation in the sex ratio has been found in Russia, i.e. more boys or fewer girls compared to expectation were born. Recently, also for Cuba an escalated sex ratio from 1987 onward has been documented and discussed in the scientific literature. Presentation of the hypothesis By the end of the eighties of the last century in Cuba as much as about 60% of the food imports were provided by the former Soviet Union. Due to its difficult economic situation, Cuba had neither the necessary insight nor the political strength to circumvent the detrimental genetic effects of imported radioactively contaminated foodstuffs after Chernobyl. We propose that the long term stable sex ratio increase in Cuba is essentially due to ionizing radiation. Testing of the hypothesis A synoptic trend analysis of Russian and Cuban annual sex ratios discloses upward jumps in 1987. The estimated jump height from 1986 to 1987 in Russia measures 0.51% with a 95% confidence interval (0.28, 0.75), p value < 0.0001. In Cuba the estimated jump height measures 2.99% (2.39, 3.60), p value < 0.0001. The hypothesis may be tested by reconstruction of imports from the world markets to Cuba and by radiological analyses of remains in Cuba for Cs-137 and Sr-90. Implications of the hypothesis If the evidence for the hypothesis is strengthened, there is potential to learn about genetic radiation risks and to prevent similar effects in present and future exposure situations. PMID:23947741

Second to fourth digit ratio, sex differences and antropometric measuments: their relationship in children.

Science.gov (United States)

Uludag, Aysegul; Tekin, Murat; Ertekin, Yusuf H; Şahin, Erkan M; Cevizci, Sibel; Cibik, Birol; Oguz, Sevilay; Erbag, Oznur

2017-04-01

The aim of this study was to determine the effect of socio-demographic factors and anthropometric measurements on 2/4 digit ratio in the school aged children. This cross-sectional study was completed in primary and secondary schools in the city center of Canakkale, Turkey. The students were seated at a table by the responsible doctor, and were asked to extend the palm of the right and left hand in the schools. Using a Vernier Caliper the 2/4 fingers were measured from the palm twice, and the results were noted together with socio-demographic information. Weight, length, waist and hip measurements were taken while students were behind a folding screen. A total of 1860 students from 5-14 years were included in the study. The right hand 2/4 digit ratio was 0.9765±0.035 and the left hand ratio was 0.9716±0.036 for girls. For the boys the ratios were 0.9688±0.035 for right hand and 0.9653±0.033 for left hand. The digit ratios of girls were significantly higher than boys and the right hand ratio was even greater. The 2/4 digit measurements of both hands of students were positively correlated with each other. In regression model left hand 2/4 ratio is dependent hip circumference, monthly income and gender as adjusted r2 0.051. The right hand 2/4 ratio was dependent gender, monthly income, hip circumference and birthweight as adjusted r2 0.041. The 2/4 digit ratio of school-aged in Turkish children differed based on gender. Digit ratios depend on the hip circumference, gender (girls have higher ratio), birthweight, gestation week and monthly income. Further research, especially the effect of monthly income, is needed.

Recurrent selection on the Winters sex-ratio genes in Drosophila simulans.

Science.gov (United States)

Kingan, Sarah B; Garrigan, Daniel; Hartl, Daniel L

2010-01-01

Selfish genes, such as meiotic drive elements, propagate themselves through a population without increasing the fitness of host organisms. X-linked (or Y-linked) meiotic drive elements reduce the transmission of the Y (X) chromosome and skew progeny and population sex ratios, leading to intense conflict among genomic compartments. Drosophila simulans is unusual in having a least three distinct systems of X chromosome meiotic drive. Here, we characterize naturally occurring genetic variation at the Winters sex-ratio driver (Distorter on the X or Dox), its progenitor gene (Mother of Dox or MDox), and its suppressor gene (Not Much Yang or Nmy), which have been previously mapped and characterized. We survey three North American populations as well as 13 globally distributed strains and present molecular polymorphism data at the three loci. We find that all three genes show signatures of selection in North America, judging from levels of polymorphism and skews in the site-frequency spectrum. These signatures likely result from the biased transmission of the driver and selection on the suppressor for the maintenance of equal sex ratios. Coalescent modeling indicates that the timing of selection is more recent than the age of the alleles, suggesting that the driver and suppressor are coevolving under an evolutionary "arms race." None of the Winters sex-ratio genes are fixed in D. simulans, and at all loci we find ancestral alleles, which lack the gene insertions and exhibit high levels of nucleotide polymorphism compared to the derived alleles. In addition, we find several "null" alleles that have mutations on the derived Dox background, which result in loss of drive function. We discuss the possible causes of the maintenance of presence-absence polymorphism in the Winters sex-ratio genes.

The potential pitfalls of studying adult sex ratios at aggregate levels in humans

NARCIS (Netherlands)

Pollet, Thomas V.; Stoevenbelt, Andrea H.; Kuppens, Toon

2017-01-01

Human adult sex ratios have been studied extensively across the biological and social sciences. While several studies have examined adult sex ratio effects in a multilevel perspective, many studies have focused on effects at an aggregated level only. In this paper, we review some key issues relating

[The sex ratio at birth: a retrospective review and commentary].

Science.gov (United States)

Aubenque, M

1989-01-01

Trends in the sex ratio are examined, and the possible effect of new biotechnologies on sex preselection is discussed. "We recall that this ratio is very stable, around 105 males for 100 females (live births). However, in France, a slight decreasing trend during the 19th century can be observed (from 107 to 104). At the present time this ratio seems to be maintained at a level of 105.3. The great demographic perturbations, particularly caused by wars, have been marked by a slight but notable increase in the indicator (106) when natality rises again after a deep depression. The variations, always small, of this indicator are more dependent on the male than on female natality, for reasons that are unclear." A comment by Paul Damiani is included (pp. 99-102). (SUMMARY IN ENG) excerpt

The sex ratio of offspring is associated with the mothers' age at menarche

DEFF Research Database (Denmark)

Fukuda, Misao; Fukuda, Kiyomi; Shimizu, Takashi

2011-01-01

BACKGROUND Early menarcheal age is a risk factor for breast and ovarian cancers and is also associated with an increased spontaneous abortion rate. The aim of this study was to investigate whether there is a link between early menarcheal age and the offspring sex ratio. METHODS We recorded the sex...... of 21208 live born infants, all singletons, born to 10 847 premenopausal women (mean attending age: 37.5 ± 7.2 years, range 22-54) who attended our clinics for obstetrical and gynaecological assessment. We calculated the sex ratio of newborn infants in relation to the mothers' age of menarche (from 9 to 18...... years) and to the number of infants per woman (i.e. fertility index). RESULTS A low offspring sex ratio (males/females) of 0.800 was observed in mothers who entered menarche at the age of 9 years; the odds ratio (OR) (95% confidence intervals) compared with those of control group with menarche at age 14...

How do sex ratios in China influence marriage decisions and intra-household resource allocation?

Science.gov (United States)

Porter, Maria

2016-06-01

This article examines how imbalanced sex ratios influence marriage decisions and household bargaining. Using data from the 1982 Chinese census, the traditional "availability ratio" is modified to reflect the degree to which men tend to marry women from different cohorts. This ratio reflects the average tendency of men to prefer women who are close in age to women who are several years younger than them by weighting cohort sizes using the proportion of people in the population who marry someone born in a different cohort. Given that men generally marry younger women, this ratio varies independently of the size of one's own birth cohort. Yet, the ratio fluctuates considerably across individuals, as the sizes of birth cohorts in China vary across time and regions. This enables us to examine how variability in such ratios may influence marriage decisions and household bargaining. The findings suggest that women exercise greater bargaining power once married. Results indicate that as women become scarcer in the marriage market, they have healthier sons. Men also delay marriage, and consume less tobacco and alcohol. This paper also highlights how sensitive findings may be to using this modified weighted availability ratio rather than a traditional unweighted availability ratio.

Flock sizes and sex ratios of canvasbacks in Chesapeake Bay and North Carolina

Science.gov (United States)

Haramis, G.M.; Derleth, E.L.; Link, W.A.

1994-01-01

Knowledge of the distribution, size, and sex ratios of flocks of wintering canvasbacks (Aythya valisineria) is fundamental to understanding the species' winter ecology and providing guidelines for management. Consequently, in winter 1986-87, we conducted 4 monthly aerial photographic surveys to investigate temporal changes in distribution, size, and sex ratios of canvasback flocks in traditional wintering areas of Chesapeake Bay and coastal North Carolina. Surveys yielded 35mm imagery of 194,664 canvasbacks in 842 flocks. Models revealed monthly patterns of flock size in North Carolina and Virginia, but no pattern of change in Maryland. A stepwise analysis of flock size and sex ratio fit a common positive slope (increasing proportion male) for all state-month datasets, except for North Carolina in February where the slope was larger (P lt 0.001). State and month effects on intercepts were significant (P lt 0.001) and confirmed a previously identified latitudinal gradient in sex ratio in the survey region. There was no relationship between flock purity (% canvasbacks vs. other species) and flock size except in North Carolina in January, February, and March when flock purity was related to flock size. Contrasting characteristics in North Carolina with regard to flock size (larger flocks) and flock purity suggested that proximate factors were reinforcing flocking behavior and possibly species fidelity there. Of possible factors, the need to locate foraging sites within this large, open-water environment was hypothesized to be of primary importance. Comparison of January 1981 and 1987 sex ratios indicated no change in Maryland, but lower (P lt 0.05) canvasback sex ratios (proportion male) in Virginia and North Carolina.

Adjusted Money's Worth Ratios in Life Annuities

OpenAIRE

Jaime Casassus; Eduardo Walker

2013-01-01

The Money's Worth Ratio (MWR) measures an annuity's actuarial fairness. It is calculated as the discounted present value of expected future payments divided by its cost. We argue that from the perspective of annuitants, this measure may overestimate the value-for-money obtained, since it does not adjust for liquidity or risk factors. Measuring these factors is challenging, requiring detailed knowledge of assets, liabilities, and of the stochastic processes followed by them. Using a multi-fact...

Population sex ratios: another consideration in the reintroduction - reinforcement debate?

Directory of Open Access Journals (Sweden)

Sergio A Lambertucci

Full Text Available Reintroduction or reinforcement (RorR of wild populations is a common conservation strategy. Many conservation projects involve the release of individuals of poorly studied species. This may lead to inefficient results or negative impacts on the conservation efforts. Here, we provide new insights into the conservation implications and potential consequences of a skew in the sex ratio of released birds and of the number of birds supplemented for the demography of a long-lived dimorphic bird species, the Andean condor (Vulturgryphus. We demonstrate that a RorR conservation program may be less effective in conserving a species if the sex ratios of the releases and the recipient populations are not considered. We also show that releases can reduce population declines but only if carried out over long periods (i.e., several decades. This can mean high costs for release programs and the added challenge of maintaining programs over time. If RorR programs are to be implemented, bearing in mind the importance of properly assessing their effectiveness, we urge conservation researchers and managers to consider the implications of sex ratio biases for wild populations, and particularly for dimorphic species with sexually despotic behaviour.

Maintaining access to safe abortion and reducing sex ratio imbalances in Asia.

Science.gov (United States)

Ganatra, Bela

2008-05-01

High sex ratios at birth (108 boys to 100 girls or higher) are seen in China, Taiwan, South Korea and parts of India and Viet Nam. The imbalance is the result of son preference, accentuated by declining fertility. Prenatal sex detection with ultrasound followed by second trimester abortion is one of the ways sex selection manifests itself, but it is not the causative factor. Advocates and governments seeking to reverse this imbalance have largely prohibited sex detection tests and/or sex selective abortion, assuming these measures would reverse the trend. Such policies have been difficult to enforce and have met with only limited success. At the same time, such policies are starting to have adverse effects on the already limited access to safe and legal second trimester abortion for reasons other than sex selection. Moreover, the sex selection issue is being used as a platform for anti-abortion rhetoric by certain groups. Maintaining access to safe abortion and achieving a decline in high sex ratios are both important goals. Both are possible if the focus shifts to addressing the conditions that drive son preference.

The sex ratio of siblings of individuals with a history of developmental language disorder

DEFF Research Database (Denmark)

Mouridsen, Svend Erik; Hauschild, Karen-Marie

2010-01-01

There is a well documented predominance of males diagnosed with neurodevelopmental disorders. The influence of sex steroids upon brain development has been suggested to mediate sex differences in developmental psychopathology, and has been epitomized in the 'extreme male brain theory......'. The objective of this study was to extend previous studies dealing with the extreme male brain theory and to study the sex ratio (proportion of males) in the siblings of 469 individuals with a developmental language disorder (DLD) who were consecutively assessed in the same clinic during a period of 10 years....... Among their 908 live-born siblings, 503 were males and 405 females. This yields a sex ratio of 0.554, which is significantly higher than the Danish live birth sex ratio of 0.514 over the same period (P = 0.02). Our findings are consistent with the hypothesis that male sex hormones may be implicated...

The mystery of missing female children in the Caucasus: an analysis of sex ratios by birth order.

Science.gov (United States)

Michael, Marc; King, Lawrence; Guo, Liang; McKee, Martin; Richardson, Erica; Stuckler, David

2013-06-01

Official data on sex ratios at birth suggest a rise in sex-selective abortions in some post-Soviet states following the introduction of ultrasonography. However, questions remain about the validity of official data in these nations as well as whether the high sex ratios at birth are a statistical artifact. Trends in sex ratios at birth from 1985 to 2009 for 12 post-Soviet states were examined using vital registration data. For the three countries that had had a Demographic and Health Survey (DHS) in 2005-2010 (Armenia, Azerbaijan and Moldova), survey data were used to calculate sex ratios at birth according to birth order, and vital registration data for 2010 were used to estimate the number of "missing" female births (if any). Official data revealed elevated sex ratios at birth in Armenia (117), Azerbaijan (116) and Georgia (121), but not in other post-Soviet states. According to DHS data, sex ratios were high in Armenia and Azerbaijan for first births (138 and 113, respectively); if the first child was a girl, the sex ratio in Armenia was even higher for the second birth (154). Overall, the number of girls born in these countries in 2010 was 10% lower than expected, consistent with 1,972 sex-selective abortions in Armenia and 8,381 in Azerbaijan. Sex ratios did not vary by birth order in Moldova. Sex-selective abortion appears to be common in Azerbaijan and Armenia. Family planning and legal interventions are needed to address this issue.

Sex ratios in juveniles and adults of Dichroplus maculipennis (Blanchard and Borellia bruneri (Rehn (Orthoptera: Acrididae

Directory of Open Access Journals (Sweden)

Yanina Mariottini

2015-06-01

Full Text Available Dichroplus maculipennis and Borellia bruneri are two of the 18 grasshopper species of actual or potential economic relevance as pests in Argentina. The objective of this study was to estimate the sex ratios for adults and older nymphs of D. maculipennis and B. bruneri in the field, and analyze possible temporal variations. The study was conducted during seven seasons (2005-06 to 2011-12 in representative plant communities of the southern Pampas region. A total of 4536 individuals of D. maculipennis, and 6038 individuals of B. bruneri were collected. The sex ratio registered in older nymphs for D. maculipennis and B. bruneri did not deviate from a 1:1 ratio (p > 0.05, suggesting that these species have such a primary sex ratio. However, a significant bias in sex composition in adults of both species was observed (p < 0.05. The sex ratio in adults of D. maculipennis was different in five of the 18 sampling dates carried out. In three sampling dates it was biased toward males, while in the other two it was biased toward females. Taking into account the sex ratio by sampling season, significant differences were recorded in two seasons. In 2007-08 the sex ratio was biased toward males (1 F:2.26 M, while in 2008-09 it was biased toward females (1.35 F:1 M. The sex ratio in adults of B. bruneri was always biased toward males (p < 0.05. We conclude that results obtained in this study indicate that various factors like differential survival, dispersion, predation, among others, could have modified the primary sex ratio in these species.

Hatchling sex ratio and female mating status in the great reed warbler, Acrocephalus arundinaceus (Aves, Passeriformes): further evidence for offspring sex ratio manipulation

Czech Academy of Sciences Publication Activity Database

Trnka, A.; Prokop, P.; Kašová, M.; Sobeková, Karolina; Kocian, Ľ.

2012-01-01

Roč. 79, č. 2 (2012), s. 212-217 ISSN 1125-0003 Institutional support: RVO:68081766 Keywords : Great reed warbler * sex ratio * social polygyny Subject RIV: EG - Zoology Impact factor: 0.890, year: 2012

A Multinomial Model of Fertility Choice and Offspring Sex-Ratios in India

OpenAIRE

Rubiana Chamarbagwala; Martin Ranger

2007-01-01

Fertility decline in developing countries may have unexpected demographic consequences. Although lower fertility improves nutrition, health, and human capital investments for surviving children, little is known about the relationship between fertility outcomes and female-male offspring sex-ratios. Particularly in countries with a cultural preference for sons, like India and China, fertility decline may deteriorate the already imbalanced sex-ratios. We use the fertility histories of over 90,00...

Manipulation of primary sex ratio in birds : Lessons from the Homing Pigeon (Columba livia domestica)

NARCIS (Netherlands)

Goerlich-Jansson, Vivian C.; Muller, Martina S.; Groothuis, Ton G. G.

2013-01-01

Across various animal taxa not only the secondary sex ratio but also the primary sex ratio (at conception) shows significant deviations from the expected equal proportions of sons and daughters. Birds are especially intriguing to study this phenomenon as avian females are the heterogametic sex (ZW);

Different male versus female breeding periodicity helps mitigate offspring sex ratio skews in sea turtles

Directory of Open Access Journals (Sweden)

Graeme Clive Hays

2014-09-01

Full Text Available The implications of climate change for global biodiversity may be profound with those species with little capacity for adaptation being thought to be particularly vulnerable to warming. A classic case of groups for concern are those animals exhibiting temperature-dependent sex-determination (TSD, such as sea turtles, where climate warming may produce single sex populations and hence extinction. We show that, globally, female biased hatchling sex ratios dominate sea turtle populations (exceeding 3:1 in >50% records, which, at-a-glance, reiterates concerns for extinction. However, we also demonstrate that more frequent breeding by males, empirically shown by satellite tracking 23 individuals and supported by a generalized bio-energetic life history model, generates more balanced operational sex ratios (OSRs. Hence, concerns of increasingly skewed hatchling sex ratios and reduced population viability are less acute than previously thought for sea turtles. In fact, in some scenarios skewed hatchling sex ratios in groups with TSD may be adaptive to ensure optimum OSRs.

Determination of sex-ratio by birth order in an urban community in Manipur.

Science.gov (United States)

Brogen, Akoijam S; Shantibala, K; Rajkumari, Bishwalata; Laishram, Jalina

2009-01-01

To determine the sex ratio by birth order and to assess the sex preference of the couples in an urban community. A cross sectional study, in an urban community in Manipur, was conducted among the currently married couples. Data on background characteristics of the couple, family pedigree chart (of the offspring) including history of abortion, stillbirth, death of child of the couple, sex preference and Pre-natal Diagnostic Techniques (Regulation and Prevention of Misuse) Act [PNDT Act] were collected through a structured interview. Data were analyzed using descriptive and chi-square statistics. There were a total of 1777 births to the 855 couples interviewed. There were 900 females per 1000 males for the 1st birth order but the sex ratio was favorable towards females in the 2nd, 3rd and 4th birth orders. Among both the husbands and wives, being more educated was significantly associated (p<0.05) with preferring lesser number of children, using new technology for sex selection and having heard of the PNDT Act. Majority of those who wanted to use new technology for sex selection (128, 56.6%) preferred to have male child. Sex ratio in this community was favorable towards females, though it was less among the first born babies.

Influence of electromagnetic pulse on the offspring sex ratio of male BALB/c mice.

Science.gov (United States)

Li, Jin-Hui; Jiang, Da-Peng; Wang, Ya-Feng; Yan, Jia-Jia; Guo, Qi-Yan; Miao, Xia; Lang, Hai-Yang; Xu, Sheng-Long; Liu, Jun-Ye; Guo, Guo-Zhen

2017-09-01

Public concern is growing about the exposure to electromagnetic fields (EMF) and its effect on male reproductive health. Detrimental effect of EMF exposure on sex hormones, reproductive performance and sex-ratio was reported. The present study was designed to clarify whether paternal exposure to electromagnetic pulse (EMP) affects offspring sex ratio in mice. 50 male BALB/c mice aged 5-6 weeks were exposed to EMP daily for 2 weeks before mated with non-exposed females at 0d, 7d, 14d, 21d and 28d after exposure. Sex hormones including total testosterone, LH, FSH, and GnRH were detected using radioimmunoassay. The sex ratio was examined by PCR and agarose gel electrophoresis. The results of D0, D21 and D28 showed significant increases compared with sham-exposed groups. The serum testosterone increased significantly in D0, D14, D21, and D28 compared with sham-exposed groups (p<0.05). Overall, this study suggested that EMP exposure may lead to the disturbance of reproductive hormone levels and affect the offspring sex ratio. Copyright © 2017. Published by Elsevier B.V.

Recent increase in sex ratio at birth in Viet Nam.

Directory of Open Access Journals (Sweden)

Christophe Z Guilmoto

Full Text Available INTRODUCTION: Since the 1980s, sex ratio at birth (male births per 100 female births has increased in many Asian countries as a result of selective abortions, but to date there has been no such evidence for Viet Nam. Our aim in this paper is to ascertain the situation with respect to sex ratio at birth in Viet Nam over the past five years. MATERIALS AND METHODS: Original data were obtained from sample population surveys in Viet Nam recording annual birth rates since 2000 of about 450,000 women, as well as from two successive birth surveys conducted for the first time in 2007 (1.1 million births. The annual population surveys include specific information on birth history and mothers' characteristics to be used for the analysis of trends and differentials in sex ratio at birth. RESULTS AND DISCUSSION: Birth history statistics indicate that the SRB in Viet Nam has recorded a steady growth since 2001. Starting from a level probably close to the biological standard of 105, the SRB reached 108 in 2005 and 112 in 2006, a value significantly above the normal level. An independent confirmation of these results comes from the surveys of births in health facilities which yielded a SRB of 110 in 2006-07. High SRB is linked to various factors such as access to modern health care, number of prenatal visits, level of higher education and employment status, young age, province of residence and prenatal sex determination. These results suggest that prenatal sex determination followed by selective abortion has recently become more common in Viet Nam. This recent trend is a consequence of various factors such as preference for sons, declining fertility, easy access to abortion, economic development as well as the increased availability of ultrasonography facilities.

Recent increase in sex ratio at birth in Viet Nam.

Science.gov (United States)

Guilmoto, Christophe Z; Hoàng, Xuyên; Van, Toan Ngo

2009-01-01

Since the 1980s, sex ratio at birth (male births per 100 female births) has increased in many Asian countries as a result of selective abortions, but to date there has been no such evidence for Viet Nam. Our aim in this paper is to ascertain the situation with respect to sex ratio at birth in Viet Nam over the past five years. Original data were obtained from sample population surveys in Viet Nam recording annual birth rates since 2000 of about 450,000 women, as well as from two successive birth surveys conducted for the first time in 2007 (1.1 million births). The annual population surveys include specific information on birth history and mothers' characteristics to be used for the analysis of trends and differentials in sex ratio at birth. Birth history statistics indicate that the SRB in Viet Nam has recorded a steady growth since 2001. Starting from a level probably close to the biological standard of 105, the SRB reached 108 in 2005 and 112 in 2006, a value significantly above the normal level. An independent confirmation of these results comes from the surveys of births in health facilities which yielded a SRB of 110 in 2006-07. High SRB is linked to various factors such as access to modern health care, number of prenatal visits, level of higher education and employment status, young age, province of residence and prenatal sex determination. These results suggest that prenatal sex determination followed by selective abortion has recently become more common in Viet Nam. This recent trend is a consequence of various factors such as preference for sons, declining fertility, easy access to abortion, economic development as well as the increased availability of ultrasonography facilities.

Spatio-temporal variation in the incubation duration and sex ratio of hawksbill hatchlings: implication for future management.

Science.gov (United States)

dei Marcovaldi, Maria A G; Santos, Armando J B; Santos, Alexsandro S; Soares, Luciano S; Lopez, Gustave G; Godfrey, Matthew H; López-Mendilaharsu, Milagros; Fuentes, Mariana M P B

2014-08-01

Climate change poses a unique threat to species with temperature dependent sex determination (TSD), such as marine turtles, where increases in temperature can result in extreme sex ratio biases. Knowledge of the primary sex ratio of populations with TSD is key for providing a baseline to inform management strategies and to accurately predict how future climate changes may affect turtle populations. However, there is a lack of robust data on offspring sex ratio at appropriate temporal and spatial scales to inform management decisions. To address this, we estimate the primary sex ratio of hawksbill hatchlings, Eretmochelys imbricata, from incubation duration of 5514 in situ nests from 10 nesting beaches from two regions in Brazil over the last 27 years. A strong female bias was estimated in all beaches, with 96% and 89% average female sex ratios produced in Bahia (BA) and Rio Grande do Norte (RN). Both inter-annual (BA, 88 to 99%; RN, 75 to 96% female) and inter-beach (BA, 92% to 97%; RN, 81% to 92% female) variability in mean offspring sex ratio was observed. These findings will guide management decisions in Brazil and provide further evidence of highly female-skew sex ratios in hawksbill turtles. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pengaruh Sex Ratio Ayam Arab Terhadap Fertilitas, Daya Tetas, Dan Bobot Tetas

OpenAIRE

Widi Astomo; Dian Septinova; Tintin Kurtini

2016-01-01

This study aimed to determine (1) This effect of sex ratio arabic chicken on fertility, hatchibility , and doc weight and (2) to determine the best sex ratio of effect arabic chicken on fertility, hatchability, and doc weight. This study was conducted in August 2015 at Tegalrejo village, Gadingrejo districk, Pringsewu regency.The research use 144 arabic chicken consisted of 18 males and 126 females. This research use the complete randomized design with 3 treatments and 6 times replications...

Health Care Use, Health Behaviors, and Medical Conditions Among Individuals in Same-Sex and Opposite-Sex Partnerships: A Cross-Sectional Observational Analysis of the Medical Expenditures Panel Survey (MEPS), 2003-2011.

Science.gov (United States)

Blosnich, John R; Hanmer, Janel; Yu, Lan; Matthews, Derrick D; Kavalieratos, Dio

2016-06-01

Prior research documents disparities between sexual minority and nonsexual minority individuals regarding health behaviors and health services utilization. However, little is known regarding differences in the prevalence of medical conditions. To examine associations between sexual minority status and medical conditions. We conducted multiple logistic regression analyses of the Medical Expenditure Panel Survey (2003-2011). We identified individuals who reported being partnered with an individual of the same sex, and constructed a matched cohort of individuals in opposite-sex partnerships. A total of 494 individuals in same-sex partnerships and 494 individuals in opposite-sex partnerships. Measures of health risk (eg, smoking status), health services utilization (eg, physician office visits), and presence of 15 medical conditions (eg, cancer, diabetes, arthritis, HIV, alcohol disorders). Same-sex partnered men had nearly 4 times the odds of reporting a mood disorder than did opposite-sex partnered men [adjusted odds ratio (aOR)=3.96; 95% confidence interval (CI), 1.85-8.48]. Compared with opposite-sex partnered women, same-sex partnered women had greater odds of heart disease (aOR=2.59; 95% CI, 1.19-5.62), diabetes (aOR=2.75; 95% CI, 1.10-6.90), obesity (aOR=1.92; 95% CI, 1.26-2.94), high cholesterol (aOR=1.89; 95% CI, 1.03-3.50), and asthma (aOR=1.90; 95% CI, 1.02-1.19). Even after adjusting for sociodemographics, health risk behaviors, and health conditions, individuals in same-sex partnerships had 67% increased odds of past-year emergency department utilization and 51% greater odds of ≥3 physician visits in the last year compared with opposite-sex partnered individuals. A combination of individual-level, provider-level, and system-level approaches are needed to reduce disparities in medical conditions and health care utilization among sexual minority individuals.

Elevated mortality among birds in Chernobyl as judged from skewed age and sex ratios.

Directory of Open Access Journals (Sweden)

Anders Pape Møller

Full Text Available Radiation has negative effects on survival of animals including humans, although the generality of this claim is poorly documented under low-dose field conditions. Because females may suffer disproportionately from the effects of radiation on survival due to differences in sex roles during reproduction, radiation-induced mortality may result in male-skewed adult sex ratios.We estimated the effects of low-dose radiation on adult survival rates in birds by determining age ratios of adults captured in mist nets during the breeding season in relation to background radiation levels around Chernobyl and in nearby uncontaminated control areas. Age ratios were skewed towards yearlings, especially in the most contaminated areas, implying that adult survival rates were reduced in contaminated areas, and that populations in such areas could only be maintained through immigration from nearby uncontaminated areas. Differential mortality in females resulted in a strongly male-skewed sex ratio in the most contaminated areas. In addition, males sang disproportionately commonly in the most contaminated areas where the sex ratio was male skewed presumably because males had difficulty finding and acquiring mates when females were rare. The results were not caused by permanent emigration by females from the most contaminated areas because none of the recaptured birds had changed breeding site, and the proportion of individuals with morphological abnormalities did not differ significantly between the sexes for areas with normal and higher levels of contamination.These findings are consistent with the hypothesis that the adult survival rate of female birds is particularly susceptible to the effects of low-dose radiation, resulting in male skewed sex ratios at high levels of radiation. Such skewed age ratios towards yearlings in contaminated areas are consistent with the hypothesis that an area exceeding 30,000 km(2 in Chernobyl's surroundings constitutes an

Lunar cycles at mating do not influence sex ratio at birth in horses.

Science.gov (United States)

Aguilar, J J; Cuervo-Arango, J; Santa Juliana, L

2015-02-01

It is scientifically demonstrated that lunar cycles have important effects on several biological events. Controversy exists about the lunar influence on human and animal parturition. In addition, in the horse industry, especially in Polo Horse breeders of Argentina and around the world there is a higher demand for female offspring than for males. The objective of this study was to determine whether there is a significant association between the lunar phase at the time of mating and the sex ratio at birth in horses. The Argentinean Stud Book provided information related to all matings registered for Thoroughbred and Arab horses between 2003 and 2011. Statistical associations were tested between dates of matings at different lunar phases or days and sex ratio at birth. A total of 65.535 gestations were studied. Overall, sex ratio at birth resulted in 33.396 fillies (50.96%) and 32.139 colts (49.04%). The percentages of males and females at birth were not statistically different amongst the different lunar phases or days. We can strongly conclude that managing the breeding dates in relation to lunar cycles in order to manipulate the sex ratio of the offspring is not a viable option in horses.

First child pregnancy: sex roles, marital and emotional adjustment

OpenAIRE

Hernandez, José Augusto Evangelho; Hutz, Cláudio Simon

2008-01-01

Esta investigação examinou as relações entre papéis sexuais, ajustamento conjugal e emocional de mulheres no período de gravidez da transição para a parentalidade. Participaram 135 mulheres recrutadas na rede pública de saúde (SUS). As gestantes estavam esperando os seus primeiros fi lhos e coabitavam com seus parceiros, independentemente de serem formalmente casadas. Os instrumentos utilizados foram o Bem Sex-Role Inventory (Bem, 1974), a Dyadic Adjustment Scale (Spanier, 1976) e a Escala Fa...

Kin discrimination and sex ratios in a parasitoid wasp

NARCIS (Netherlands)

Reece, S.E.; Shuker, D.M.; Pen, I.R.; Duncan, A.B.; Choudhary, A.; Batchelor, C.M.; West, S.A.

Sex ratio theory provides a clear and simple way to test if nonsocial haplodiploid wasps can discriminate between kin and nonkin. Specifically, if females can discriminate siblings from nonrelatives, then they are expected to produce a higher proportion of daughters if they mate with a sibling. This

Thermal fluctuation within nests and predicted sex ratio of Morelet's Crocodile.

Science.gov (United States)

Escobedo-Galván, Armando H; López-Luna, Marco A; Cupul-Magaña, Fabio G

2016-05-01

Understanding the interplay between thermal variations and sex ratio in reptiles with temperature-dependent sex determination is the first step for developing long-term conservation strategies. In case of crocodilians, the information is fragmentary and insufficient for establishing a general framework to consider how thermal fluctuation influence sex determination under natural conditions. The main goal of this study was to analyze thermal variation in nests of Crocodylus moreletii and to discuss the potential implications for predicting offspring sex ratio. The study was carried out at the Centro de Estudios Tecnológicos del Mar N° 2 and at the Sistemas Productivos Cocodrilo, Campeche, Mexico. Data was collected in the nesting season of Morelet's Crocodiles during three consecutive seasons (2007-2009). Thermal fluctuations for multiple areas of the nest chamber were registered by data loggers. We calculate the constant temperature equivalent based on thermal profiles among nests to assess whether there are differences between the nest temperature and its equivalent to constant temperature. We observed that mean nest temperature was only different among nests, while daily thermal fluctuations vary depending on the depth position within the nest chamber, years and nests. The constant temperature equivalent was different among and within nests, but not among survey years. We observed differences between constant temperature equivalent and mean nest temperature both at the top and in the middle of the nest cavities, but were not significantly different at the bottom of nest cavities. Our results enable examine and discuss the relevance of daily thermal fluctuations to predict sex ratio of the Morelet's Crocodile. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sex Ratio and Twinning in Women with Hyperemesis or Pre-eclampsia

DEFF Research Database (Denmark)

Basso, Olga; Olsen, Jørn

2001-01-01

We examined twinning and fetal gender in births of women with a hospital diagnosis of pre-eclampsia or hyperemesis. We also investigated sex ratio in infants whose mothers had had hyperemesis or pre-eclampsia in a different pregnancy. From all the hospitalized cases in Denmark between 1980 and 1996...... we extracted 6,227 births with hyperemesis and 24,764 with pre-eclampsia. Twins were more frequent in pregnancies with either condition. The male to female sex ratio was 1.04 (95%CI = 1.02-1.05) in the reference population, 0.87 (95% CI = 0.82-0.91) in births with hyperemesis, and 1.10 (95% CI = 1...

An adaptive annual rhythm in the sex of first pigeon eggs

NARCIS (Netherlands)

Dijkstra, Cor; Riedstra, Bernd; Dekker, Arjan; Goerlich, Vivian C.; Daan, Serge; Groothuis, Ton G. G.

When the reproductive value of male and female offspring varies differentially, parents are predicted to adjust the sex ratio of their offspring to maximize their fitness (Trivers and Willard, Science 179:90-92, 1973). Two factors have been repeatedly linked to skews in avian offspring sex ratio.

Steroid Hormones and Female Energy Balance: Relation to Offspring Primary Sex Ratio

NARCIS (Netherlands)

Aslam, M.L.; Woelders, H.

2017-01-01

Birds can manipulate the offspring sex ratio under natural and experimental conditions. Various factors related to the avian mother, as well as her eggs, have been reported to be linked with the sex determination process. These factors appear to affect the chance of laying a male or female egg

Differences in Movement Pattern and Detectability between Males and Females Influence How Common Sampling Methods Estimate Sex Ratio.

Directory of Open Access Journals (Sweden)

João Fabrício Mota Rodrigues

Full Text Available Sampling the biodiversity is an essential step for conservation, and understanding the efficiency of sampling methods allows us to estimate the quality of our biodiversity data. Sex ratio is an important population characteristic, but until now, no study has evaluated how efficient are the sampling methods commonly used in biodiversity surveys in estimating the sex ratio of populations. We used a virtual ecologist approach to investigate whether active and passive capture methods are able to accurately sample a population's sex ratio and whether differences in movement pattern and detectability between males and females produce biased estimates of sex-ratios when using these methods. Our simulation allowed the recognition of individuals, similar to mark-recapture studies. We found that differences in both movement patterns and detectability between males and females produce biased estimates of sex ratios. However, increasing the sampling effort or the number of sampling days improves the ability of passive or active capture methods to properly sample sex ratio. Thus, prior knowledge regarding movement patterns and detectability for species is important information to guide field studies aiming to understand sex ratio related patterns.

Differences in Movement Pattern and Detectability between Males and Females Influence How Common Sampling Methods Estimate Sex Ratio.

Science.gov (United States)

Rodrigues, João Fabrício Mota; Coelho, Marco Túlio Pacheco

2016-01-01

Sampling the biodiversity is an essential step for conservation, and understanding the efficiency of sampling methods allows us to estimate the quality of our biodiversity data. Sex ratio is an important population characteristic, but until now, no study has evaluated how efficient are the sampling methods commonly used in biodiversity surveys in estimating the sex ratio of populations. We used a virtual ecologist approach to investigate whether active and passive capture methods are able to accurately sample a population's sex ratio and whether differences in movement pattern and detectability between males and females produce biased estimates of sex-ratios when using these methods. Our simulation allowed the recognition of individuals, similar to mark-recapture studies. We found that differences in both movement patterns and detectability between males and females produce biased estimates of sex ratios. However, increasing the sampling effort or the number of sampling days improves the ability of passive or active capture methods to properly sample sex ratio. Thus, prior knowledge regarding movement patterns and detectability for species is important information to guide field studies aiming to understand sex ratio related patterns.

Sex ratio of lambs born from assisted reproductive technologies ...

African Journals Online (AJOL)

The objective of the present study was to investigate sex ratio of offspring resulting from superstimulated donors from two different breeds and artificially inseminated ewes from three different breeds. Romanov (n = 5) and Charollais (n = 6) (2 - 7 years of age) donors were superovulated using FSH-p with 400 mg ...

Sex ratio and time to pregnancy: analysis of four large European population surveys

DEFF Research Database (Denmark)

Joffe, Mike; Bennett, James; Best, Nicky

2007-01-01

To test whether the secondary sex ratio (proportion of male births) is associated with time to pregnancy, a marker of fertility. Design Analysis of four large population surveys. Setting Denmark and the United Kingdom. Participants 49 506 pregnancies.......To test whether the secondary sex ratio (proportion of male births) is associated with time to pregnancy, a marker of fertility. Design Analysis of four large population surveys. Setting Denmark and the United Kingdom. Participants 49 506 pregnancies....

The Relationship of Body Length and Ratio Pappilla with Sex in Gobi Fish (Sicyopterus macrostetholepis

Directory of Open Access Journals (Sweden)

Rona Taula Sari

2017-07-01

Full Text Available Research about the relationship of body length and ratio papilla with sex in goby fish (S. macrostetholepis Blkr. has been done at Animal Structure and Developmental Laboratory, Biologi Department, Faculty of Matematics and Natural Sciences, Andalas University, Padang, which purposed to analyse the relationship of body length and ratio papilla with sex of goby fish (S. macrostetholepis Blkr.. The samples were taken in wild stream area at Batangkuranji river, Padang City. This research used descriptive method and data were analyzed by qualitatively and quantitatively. The results of investigation showed that in several goby fishes (S. macrostetholepis Blkr. with different sex had the same of body length and the same of ratio papilla. So, there was not relationship between of body length and ratio papilla with sex.  Goby fishes (S. macrostetholepis Blkr. it belongs to the hermaphrodite protogini, which the androgynous young females, while in adulthood, it would change sex to male. The results of this study are expected to add to the treasures of knowledge and information about reproductive gobies (S. macrostetholepis Blkr. in the preservation and development of fish farming.   

Secondary sex ratio in relation to exposures to polychlorinated biphenyls, dichlorodiphenyl dichloroethylene and methylmercury

DEFF Research Database (Denmark)

Timmermann, Clara Amalie Gade; Choi, Anna L; Petersen, Maria Skaalum

2017-01-01

This study was undertaken to assess the potential impact of maternal exposures to polychlorinated biphenyl (PCB), dichlorodiphenyl dichloroethylene (DDE) and methylmercury on the secondary sex ratios (the ratio of male to female live births) over a span of 23 years. The study includes prospective......% CI = 2-17%), respectively, of giving birth to a boy. In conclusion, maternal exposure to ΣPCB, DDE and methylmercury was associated with a slightly increased secondary sex ratio. The impact of paternal exposures could not be taken into account and deserves attention....

Variation in offspring sex ratio of a long-lived sexually dimorphic raptor, the eastern imperial eagle (Aquila heliaca)

Science.gov (United States)

Todd E. Katzner; Daniel S. Jackson; Jamie Ivy; Evgeny A. Bragin; Andrew Dewoody

2014-01-01

Sex ratio theory attempts to explain observed variation in offspring sex ratio at both the population and the brood levels. In the context of low-fecundity organisms producing high-investment offspring, the drivers of adaptive variation in sex ratio are incompletely understood. For raptors that display reverse sexual dimorphism (RSD), preferential allocation of...

SEASONAL-VARIATION IN THE SEX-RATIO OF MARSH HARRIER CIRCUS-AERUGINOSUS BROODS

NARCIS (Netherlands)

ZIJLSTRA, M; DAAN, S; BRUINENBERGRINSMA, J

1992-01-01

1. Analysis of the sexes of 2260 nestlings in 735 marsh harrier broods revealed an overall excess [sex ratio (SR) = 54.8%] of males, and a significant increase in the proportion of males with progressive laying date (d = day of the year): In [SR/(1-SR)] = -1.286 + 0.013 d. 2. We argue that it is

Sibling Sex Ratio and Birth Order in Early-Onset Gender Dysphoric Adolescents

NARCIS (Netherlands)

Schagen, S.E.E.; Delemarre-van de Waal, H.A.; Blanchard, R.; Cohen-Kettenis, P.T.

2012-01-01

Several sibship-related variables have been studied extensively in sexual orientation research, especially in men. Sibling sex ratio refers to the ratio of brothers to sisters in the aggregate sibships of a group of probands. Birth order refers to the probands' position (e.g., first-born,

Psychological adjustment to amputation: variations on the bases of sex, age and cause of limb loss

International Nuclear Information System (INIS)

Ali, S.; Haider, S.K.F.

2017-01-01

Amputation is the removal of a limb or part of a limb by a surgical procedure in order to save the life of a person. The underlying reasons behind the occurrence of this tragic incidence may be varied. However, irrespective of its cause limb loss is associated with wide range of life challenges. The study was done to investigate the psychological sequel of an individual after losing a limb and to know the level of strain and pressure they experience after this traumatic event. It also attempts to examine the moderating role of some demographic traits such as age, sex and cause of limb loss in psychosocial adjustment to amputation. Methods: The study includes 100 adult amputees of both genders and the data was collected from major government and private hospitals of Peshawar district. Demographic data sheet was constructed in order to know the demographics traits of amputees and a standardize Psychological Adjustment Scale developed by Sabir (1999) was used to find out the level of psychological adjustment after limb loss. Results: Nearly all the amputees' exhibit signs of psychological maladjustment at varying degrees. Males showed much greater signs of maladjustment than women and young adults were much psychologically shattered and disturbed as a result of limb loss. Amputation caused by planned medical reasons leads to less adjustment issues as compared to unplanned accidental amputation in which patient were not mentally prepare to accept this loss. Conclusion: Psychological aspect of amputation is an important aspect of limb loss which needs to be addressed properly in order to rehabilitate these patients and helps them to adjust successfully to their limb loss. (author)

Effect of Temperature on Reproduction and Sex Ratio of Guppy (Poecilia reticulata Peters)

OpenAIRE

H. Arfah; S. Mariam; . Alimuddin

2007-01-01

Water temperature could affect the reproduction of broodstock and sex ratio of progeny.  In this study, broodstock of guppy (Poecilia reticulata Peters) was reared in different temperature to determine its effect on reproduction of broodstock and sex ratio of their progeny. The result of study show that broodstock reared at 27°C produced more fry (16 males mean) than that of 30°C (10 males), while broodstock reared at 33°C produced no progeny.  Percentage of male fish produced by broodstock r...

[Paternal exposure to occupational electromagnetic radiation and sex ratio of the offspring: a meta-analysis].

Science.gov (United States)

Tong, Shu-Hui; Liu, Yi-Ting; Liu, Yang

2013-02-01

To investigate the association between paternal exposure to occupational electromagnetic radiation and the sex ratio of the offspring. We searched various databases, including PubMed, Embase, Cochrane Library, OVID, Bioscience Information Service (BIOSIS), China National Knowledge Infrastructure, VIP Database for Chinese Technical Periodicals and Wanfang Database, for the literature relevant to the association of paternal exposure to occupational electromagnetic radiation with the sex ratio of the offspring. We conducted a meta-analysis on their correlation using Stata 11.0. There was no statistically significant difference in the sex ratio between the offspring with paternal exposure to occupational electromagnetic radiation and those without (pooled OR = 1.00 [95% CI: 0.95 -1.05], P = 0.875). Subgroup analysis of both case-control and cohort studies revealed no significant difference (pooled OR = 1.03 [95% CI: 0.99 -1.08], P = 0.104 and pooled OR = 0.98 [95% CI: 0.99 -1.08], P = 0.186, respectively). Paternal exposure to occupational electromagnetic radiation is not correlated with the sex ratio of the offspring.

Sex ratios, mating frequencies and relative abundance of sympatric millipedes in the genus Chersastus (Diplopoda: Pachybolidae

Directory of Open Access Journals (Sweden)

Mark Ian Cooper

2014-12-01

Full Text Available Three hypotheses exist for explaining climbing behavior in millipedes: 1 waterlogging, 2 detritus limiting, and 3 mate avoidance. Data of sex ratios, mating frequency and relative abundance are provided to suggest an alternative explanation for the pattern in sympatric forest millipedes. Sex ratio differences - from equality - were tested using a G-test comparing millipedes on and above ground. Mating frequencies were calculated based on the percentage of paired individuals. Relative abundance may correlate with male-biases in the sex ratios. All three factors suggest Chersastus inscriptus has a higher reproductive potential than C. anulatus. This is evidence for mating hotspots.

Seed sexing revealed female bias in two Rumex species

Directory of Open Access Journals (Sweden)

Dagmara Kwolek

2011-07-01

Full Text Available Sex-ratio bias in seeds of dioecious Rumex species with sex chromosomes is an interesting and still unsettled issue. To resolve gender among seeds of R. acetosa and R. thyrsiflorus (two species with an XX/XY1Y2 sex chromosome system, this work applied a PCR-based method involving DNA markers located on Y chromosomes. Both species showed female-biased primary sex ratios, with female bias greater in R. acetosa than in R. thyrsiflorus. The observed predominance of female seeds is consistent with the view that the female biased sex ratios in Rumex are conditioned not only postzygotically but also prezygotically.

Sex ratio meiotic drive as a plausible evolutionary mechanism for hybrid male sterility.

Science.gov (United States)

Zhang, Linbin; Sun, Tianai; Woldesellassie, Fitsum; Xiao, Hailian; Tao, Yun

2015-03-01

Biological diversity on Earth depends on the multiplication of species or speciation, which is the evolution of reproductive isolation such as hybrid sterility between two new species. An unsolved puzzle is the exact mechanism(s) that causes two genomes to diverge from their common ancestor so that some divergent genes no longer function properly in the hybrids. Here we report genetic analyses of divergent genes controlling male fertility and sex ratio in two very young fruitfly species, Drosophila albomicans and D. nasuta. A majority of the genetic divergence for both traits is mapped to the same regions by quantitative trait loci mappings. With introgressions, six major loci are found to contribute to both traits. This genetic colocalization implicates that genes for hybrid male sterility have evolved primarily for controlling sex ratio. We propose that genetic conflicts over sex ratio may operate as a perpetual dynamo for genome divergence. This particular evolutionary mechanism may largely contribute to the rapid evolution of hybrid male sterility and the disproportionate enrichment of its underlying genes on the X chromosome--two patterns widely observed across animals.

The effect of climate fluctuation on chimpanzee birth sex ratio.

Directory of Open Access Journals (Sweden)

Hjalmar S Kühl

Full Text Available Climate and weather conditions, such as the North Atlantic Oscillation, precipitation and temperature influence the birth sex ratio (BSR of various higher latitude species, including deer, elephant seals or northern human populations. Although, tropical regions show only little variation in temperature, climate and weather conditions can fluctuate with consequences for phenology and food resource availability. Here, we evaluate, whether the BSR of chimpanzees, inhabiting African tropical forests, is affected by climate fluctuations as well. Additionally, we evaluate, if variation in consumption of a key food resource with high nutritional value, Coula edulis nuts, is linked to both climate fluctuations and variation in BSR. We use long-term data from two study groups located in Taï National Park, Côte d'Ivoire to assess the influence of local weather conditions and the global climate driver El Niño Southern Oscillation (ENSO on offspring sex. Côte d'Ivoire has experienced considerable climate variation over the last decades, with increasing temperature and declining precipitation. For both groups we find very similar time windows around the month of conception, in which offspring sex is well predicted by ENSO, with more males following low ENSO values, corresponding to periods of high rainfall. Furthermore, we find that the time spent cracking and feeding on Coula nuts is strongly influenced by climate conditions. Although, some of our analysis suggest that a higher proportion of males is born after periods with higher nut consumption frequency, we cannot conclude decisively at this point that nut consumption may influence shifts in BSR. All results combined suggest that also chimpanzees may experience climate related shifts in offspring sex ratios as response to climate fluctuation.

The post-orgasmic prolactin increase following intercourse is greater than following masturbation and suggests greater satiety.

Science.gov (United States)

Brody, Stuart; Krüger, Tillmann H C

2006-03-01

Research indicates that prolactin increases following orgasm are involved in a feedback loop that serves to decrease arousal through inhibitory central dopaminergic and probably peripheral processes. The magnitude of post-orgasmic prolactin increase is thus a neurohormonal index of sexual satiety. Using data from three studies of men and women engaging in masturbation or penile-vaginal intercourse to orgasm in the laboratory, we report that for both sexes (adjusted for prolactin changes in a non-sexual control condition), the magnitude of prolactin increase following intercourse is 400% greater than that following masturbation. The results are interpreted as an indication of intercourse being more physiologically satisfying than masturbation, and discussed in light of prior research reporting greater physiological and psychological benefits associated with coitus than with any other sexual activities.

Pre-conception energy balance and secondary sex ratio--partial support for the Trivers-Willard hypothesis in dairy cows.

Science.gov (United States)

Roche, J R; Lee, J M; Berry, D P

2006-06-01

According to the Trivers-Willard hypothesis, maternal condition at or around conception affects the secondary sex ratio in mammals. However, there are little or no data available on indicators of maternal condition in dairy cows on the sex of the resultant offspring. A total of 76,607 body condition score (BCS; scale of 1 to 5) records and 76,611 body weight (BW) records from 3,209 lactations across 1,172 cows were extracted from a research database collated from one research herd between 1986 and 2004, inclusive. Exclusion of multiple births and cows with no information before calving (e.g., nulliparous animals) resulted in 2,029 records with BCS and BW observations from the previous calving, and 2,002 and 1,872 lactations with BCS and BW observations at conception and midgestation, respectively. Change in BCS and BW between calving and conception and between conception and midgestation was calculated per lactation. Generalized estimating equations were used to model the logit of the probability of a male calf, in which cow was included as a repeated effect with a first-order autoregressive correlation structure assumed among records within cow. Of the BCS variables investigated, there was a linear relationship between the logit of the probability of a male calf and BCS change between calving and conception, the rate of BCS change over this period (BCS divided by days in milk), and BCS at the calving event immediately before conception. The birth of a bull calf was 1.85 times more likely in cows that lost no BCS from calving to conception compared with cows that lost one BCS unit from calving to conception. This increase in odds was equivalent to a 14% unit increase in the probability of a male calf (from 54 to 68%). The amount of BW lost between calving and conception and the rate of loss affected the sex of the resultant offspring. Less BW loss or greater BW gain between calving and conception was associated with greater likelihood of a male calf. Results

Violence prevention and municipal licensing of indoor sex work venues in the Greater Vancouver Area: narratives of migrant sex workers, managers and business owners.

Science.gov (United States)

Anderson, Solanna; Jia, Jessica Xi; Liu, Vivian; Chattier, Jill; Krüsi, Andrea; Allan, Sarah; Maher, Lisa; Shannon, Kate

2015-01-01

Using a socio-ecological, structural determinants framework, this study assesses the impact of municipal licensing policies and related policing practices across the Greater Vancouver Area (Canada) on the risk of violence within indoor sex work venues. Qualitative interviews were conducted with 46 migrant/immigrant sex workers, managers and owners of licensed indoor sex work establishments and micro-brothels. Findings indicate that policing practices and licensing requirements increase sex workers' risk of violence and conflict with clients and result in heightened stress, an inability to rely on police support, lost income and the displacement of sex workers to more hidden informal work venues. Prohibitive licensing and policing practices prevent sex workers, managers and owners from adopting safer workplace measures and exacerbate health and safety risks for sex workers. This study provides critical evidence of the negative public health implications of prohibitive municipal licensing in the context of a criminalised and enforcement-based approach to sex work. Workplace safety recommendations include the decriminalisation of sex work and the elimination of disproportionately high fees for licences, criminal record restrictions, door lock restrictions, employee registration requirements and the use of police as licensing inspectors.

Flow cytometric sexing of spider sperm reveals an equal sperm production ratio in a female-biased species

DEFF Research Database (Denmark)

Vanthournout, Bram; Deswarte, K; Hammad, H

2014-01-01

research. Pinpointing the underlying mechanism of sex ratio bias is challenging owing to the multitude of potential sex ratio-biasing factors. In the dwarf spider, Oedothorax gibbosus, infection with the bacterial endosymbiont Wolbachia results in a female bias. However, pedigree analysis reveals...

The Sex Ratio of Full and Half Siblings of People Diagnosed With ADHD in Childhood and Adolescence

DEFF Research Database (Denmark)

Mouridsen, Svend Erik Birkebæk; Rich, Bente; Isager, Torben

2014-01-01

Objective:It has been suggested that high levels of prenatal testosterone exposure are implied in the etiology of male preponderance disorders such as autism spectrum disorder and ADHD. Within this scope, we studied the sex ratio (proportion of males) in siblings of individuals diagnosed with ADHD...... in childhood and adolescence. Method: We did a nationwide, register-based cohort study of the sex ratio in siblings of the 16,381 patients in Denmark diagnosed with ADHD at age 17 years and younger and registered in the nationwide Danish Psychiatric Central Register between January 1, 1994 and May 28, 2013....... Results: Among the 33,151 siblings, 17,041 were males and 16,110 females. This yields a sex ratio of 0.514, which is not statistically significant different from the Danish live birth sex ratio of 0.513 during the relevant years (p = .70). Conclusion: These findings provide no support for the hypothesis...

The Impact of Attention-Deficit/Hyperactivity Disorder on Preadolescent Adjustment May Be Greater for Girls than for Boys

Science.gov (United States)

Elkins, Irene J.; Malone, Steve; Keyes, Margaret; Iacono, William G.; McGue, Matt

2011-01-01

Whether gender differences exist in the impairment associated with attention-deficit/hyperactivity disorder (ADHD) is still largely unknown, because most samples have few affected girls or include only one sex. The current study evaluated whether ADHD affects adjustment differently for girls than boys in a population-based cohort of 11-year-olds…

Net Stable Funding Ratio: Impact on Funding Value Adjustment

OpenAIRE

Siadat, Medya; Hammarlid, Ola

2017-01-01

In this paper we investigate the relationship between Funding Value Adjustment (FVA) and Net Stable Funding Ratio (NSFR). FVA is defined in a consistent way with NSFR such that the new framework of FVA monitors the costs due to keeping NSFR at an acceptable level, as well. In addition, the problem of choosing the optimal funding strategy is formulated as a shortest path problem where the proposed FVA framework is applied in the optimization process. The solution provides us with the optimal f...

Sex ratio of five species of pelagic copepods from Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Saraswathy, M.; Santhakumari, V.

Sex ratio in five species from south and southeast coast of India varied remarkably. Five species were selected for the present investigation. Range in the percentage of males was from 8 to 121 in @iUndinula vulgaris@@ (Dana), 16-425 in @i...

Explaining the Rapid Increase in Nigeria's Sex Ratio at Birth: Factors and Implications.

Science.gov (United States)

Kaba, Amadu J

2015-06-01

This paper examines the rapid increase in Nigeria's sex ratio at birth from 1.03 boys born for every 1 girl born in each year from 1996-2008 to 1.06 in each year from 2009-2014, second only to Tunisia in Africa at 1.07. The average sex ratio at birth in the world in 2014 was 1.07. In most Black African nations or Black majority nations, it is 1.03 or less. Among the factors presented for this development are: historical fluctuations of sex ratio at birth; geography and ethnicity; male preference/chasing a son; Age of parents; high death rates of male infants and males in general; and wealth/socioeconomic status. Among the potential implications are: young and poor men in Nigeria may not be able to find brides and form families due to a potential shortage of females; emigration of young and poor Nigerian men to West (Africa) and elsewhere to seek brides and form families; immigration of marriage age women from West (Africa) and around the world to Nigeria to seek husbands; and low contraceptive use and high fertility rates in Nigeria.

Sex ratio meiotic drive as a plausible evolutionary mechanism for hybrid male sterility.

Directory of Open Access Journals (Sweden)

Linbin Zhang

2015-03-01

Full Text Available Biological diversity on Earth depends on the multiplication of species or speciation, which is the evolution of reproductive isolation such as hybrid sterility between two new species. An unsolved puzzle is the exact mechanism(s that causes two genomes to diverge from their common ancestor so that some divergent genes no longer function properly in the hybrids. Here we report genetic analyses of divergent genes controlling male fertility and sex ratio in two very young fruitfly species, Drosophila albomicans and D. nasuta. A majority of the genetic divergence for both traits is mapped to the same regions by quantitative trait loci mappings. With introgressions, six major loci are found to contribute to both traits. This genetic colocalization implicates that genes for hybrid male sterility have evolved primarily for controlling sex ratio. We propose that genetic conflicts over sex ratio may operate as a perpetual dynamo for genome divergence. This particular evolutionary mechanism may largely contribute to the rapid evolution of hybrid male sterility and the disproportionate enrichment of its underlying genes on the X chromosome--two patterns widely observed across animals.

WormGender - Open-Source Software for Automatic Caenorhabditis elegans Sex Ratio Measurement.

Directory of Open Access Journals (Sweden)

Marta K Labocha

Full Text Available Fast and quantitative analysis of animal phenotypes is one of the major challenges of current biology. Here we report the WormGender open-source software, which is designed for accurate quantification of sex ratio in Caenorhabditis elegans. The software functions include, i automatic recognition and counting of adult hermaphrodites and males, ii a manual inspection feature that enables manual correction of errors, and iii flexibility to use new training images to optimize the software for different imaging conditions. We evaluated the performance of our software by comparing manual and automated assessment of sex ratio. Our data showed that the WormGender software provided overall accurate sex ratio measurements. We further demonstrated the usage of WormGender by quantifying the high incidence of male (him phenotype in 27 mutant strains. Mutants of nine genes (brc-1, C30G12.6, cep-1, coh-3, him-3, him-5, him-8, skr-1, unc-86 showed significant him phenotype. The WormGender is written in Java and can be installed and run on both Windows and Mac platforms. The source code is freely available together with a user manual and sample data at http://www.QuantWorm.org/. The source code and sample data are also available at http://dx.doi.org/10.6084/m9.figshare.1541248.

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

Science.gov (United States)

Dodd, C.K.

1997-01-01

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.

Impaired imprinted X chromosome inactivation is responsible for the skewed sex ratio following in vitro fertilization

Science.gov (United States)

Tan, Kun; An, Lei; Miao, Kai; Ren, Likun; Hou, Zhuocheng; Tao, Li; Zhang, Zhenni; Wang, Xiaodong; Xia, Wei; Liu, Jinghao; Wang, Zhuqing; Xi, Guangyin; Gao, Shuai; Sui, Linlin; Zhu, De-Sheng; Wang, Shumin; Wu, Zhonghong; Bach, Ingolf; Chen, Dong-bao; Tian, Jianhui

2016-01-01

Dynamic epigenetic reprogramming occurs during normal embryonic development at the preimplantation stage. Erroneous epigenetic modifications due to environmental perturbations such as manipulation and culture of embryos during in vitro fertilization (IVF) are linked to various short- or long-term consequences. Among these, the skewed sex ratio, an indicator of reproductive hazards, was reported in bovine and porcine embryos and even human IVF newborns. However, since the first case of sex skewing reported in 1991, the underlying mechanisms remain unclear. We reported herein that sex ratio is skewed in mouse IVF offspring, and this was a result of female-biased peri-implantation developmental defects that were originated from impaired imprinted X chromosome inactivation (iXCI) through reduced ring finger protein 12 (Rnf12)/X-inactive specific transcript (Xist) expression. Compensation of impaired iXCI by overexpression of Rnf12 to up-regulate Xist significantly rescued female-biased developmental defects and corrected sex ratio in IVF offspring. Moreover, supplementation of an epigenetic modulator retinoic acid in embryo culture medium up-regulated Rnf12/Xist expression, improved iXCI, and successfully redeemed the skewed sex ratio to nearly 50% in mouse IVF offspring. Thus, our data show that iXCI is one of the major epigenetic barriers for the developmental competence of female embryos during preimplantation stage, and targeting erroneous epigenetic modifications may provide a potential approach for preventing IVF-associated complications. PMID:26951653

Effects of larval-juvenile treatment with perchlorate and co-treatment with thyroxine on zebrafish sex ratios

Science.gov (United States)

Mukhi, S.; Torres, L.; Patino, R.

2007-01-01

The objective of this study was to determine the effect of larval-juvenile exposure to perchlorate, a thyroid hormone synthesis inhibitor, on the establishment of gonadal sex ratios in zebrafish. Zebrafish were exposed to untreated water or water containing perchlorate at 100 or 250 ppm for a period of 30 days starting at 3 days postfertilization (dpf). Recovery treatments consisted of a combination of perchlorate and exogenous thyroxine (T4; 10 nM). Thyroid histology was assessed at the end of the treatment period (33 dpf), and gonadal histology and sex ratios were determined in fish that were allowed an additional 10-day period of growth in untreated water. As expected, exposure to perchlorate caused changes in thyroid histology consistent with hypothyroidism and these effects were reversed by co-treatment with exogenous T4. Perchlorate did not affect fish survival but co-treatment with T4 induced higher mortality. However, relative to the corresponding perchlorate concentration, co-treatment with T4 caused increased mortality only at a perchlorate concentration of 100 ppm. Perchlorate alone or in the presence of T4 suppressed body length at 43 dpf relative to control values. Perchlorate exposure skewed the sex ratio toward female in a concentration-dependent manner, and co-treatment with T4 not only blocked the feminizing effect of perchlorate but also overcompensated by skewing the sex ratio towards male. Moreover, co-treatment with T4 advanced the onset of spermatogenesis in males. There was no clear association between sex ratios and larval survival or growth. We conclude that endogenous thyroid hormone plays a role in the establishment of gonadal sex phenotype during early development in zebrafish. ?? 2006 Elsevier Inc. All rights reserved.

Adjusted Empirical Likelihood Method in the Presence of Nuisance Parameters with Application to the Sharpe Ratio

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Yuejiao Fu

2018-04-01

Full Text Available The Sharpe ratio is a widely used risk-adjusted performance measurement in economics and finance. Most of the known statistical inferential methods devoted to the Sharpe ratio are based on the assumption that the data are normally distributed. In this article, without making any distributional assumption on the data, we develop the adjusted empirical likelihood method to obtain inference for a parameter of interest in the presence of nuisance parameters. We show that the log adjusted empirical likelihood ratio statistic is asymptotically distributed as the chi-square distribution. The proposed method is applied to obtain inference for the Sharpe ratio. Simulation results illustrate that the proposed method is comparable to Jobson and Korkie’s method (1981 and outperforms the empirical likelihood method when the data are from a symmetric distribution. In addition, when the data are from a skewed distribution, the proposed method significantly outperforms all other existing methods. A real-data example is analyzed to exemplify the application of the proposed method.

Sex-specific effects of altered competition on nestling growth and survival: an experimental manipulation of brood size and sex ratio.

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Nicolaus, Marion; Michler, Stephanie P M; Ubels, Richard; van der Velde, Marco; Komdeur, Jan; Both, Christiaan; Tinbergen, Joost M

2009-03-01

1. An increase of competition among adults or nestlings usually negatively affects breeding output. Yet little is known about the differential effects that competition has on the offspring sexes. This could be important because it may influence parental reproductive decisions. 2. In sexual size dimorphic species, two main contradictory mechanisms are proposed regarding sex-specific effects of competition on nestling performance assuming that parents do not feed their chicks differentially: (i) the larger sex requires more resources to grow and is more sensitive to a deterioration of the rearing conditions ('costly sex hypothesis'); (ii) the larger sex has a competitive advantage in intra-brood competition and performs better under adverse conditions ('competitive advantage hypothesis'). 3. In the present study, we manipulated the level of sex-specific sibling competition in a great tit population (Parus major) by altering simultaneously the brood size and the brood sex ratio on two levels: the nest (competition for food among nestlings) and the woodlot where the parents breed (competition for food among adults). We investigated whether altered competition during the nestling phase affected nestling growth traits and survival in the nest and whether the effects differed between males, the larger sex, and females. 4. We found a strong negative and sex-specific effect of experimental brood size on all the nestling traits. In enlarged broods, sexual size dimorphism was smaller which may have resulted from biased mortality towards the less competitive individuals i.e. females of low condition. No effect of brood sex ratio on nestling growth traits was found. 5. Negative brood size effects on nestling traits were stronger in natural high-density areas but we could not confirm this experimentally. 6. Our results did not support the 'costly sex hypothesis' because males did not suffer from higher mortality under harsh conditions. The 'competitive advantage hypothesis' was

Determination of Sperm Sex Ratio in Bovine Semen Using Multiplex Real-time Polymerase Chain Reaction

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Trisadee Khamlor

2014-10-01

Full Text Available Gender selection is important in livestock industries; for example, female calves are required in the dairy industry. Sex-sorted semen is commonly used for the production of calves of the desired gender. However, assessment of the sex ratio of the sorted semen is tedious and expensive. In this study, a rapid, cost effective and reliable method for determining the sex ratio was developed using a multiplex real-time polymerase chain reaction (PCR assay. In this assay, the X and Y chromosome-specific markers, i.e., bovine proteolipid protein (PLP gene and sex-determining region Y (SRY were simultaneously quantified in a single tube. The multiplex real-time PCR assay was shown to have high amplification efficiencies (97% to 99% comparable to the separated-tube simplex real-time PCR assay. The results obtained from both assays were not significantly different (p>0.05. The multiplex assay was validated using reference DNA of known X ratio (10%, 50%, and 90% as templates. The measured %X in semen samples were the same within 95% confidence intervals as the expected values, i.e., >90% in X-sorted semen, <10% in Y-sorted semen and close to 50% in the unsorted semen. The multiplex real-time PCR assay as shown in this study can thus be used to assess purity of sex-sorted semen.

Birth order and sibling sex ratio of children and adolescents referred to a gender identity service.

Science.gov (United States)

Vanderlaan, Doug P; Blanchard, Ray; Wood, Hayley; Zucker, Kenneth J

2014-01-01

In adult male samples, homosexuality is associated with a preponderance of older brothers (i.e., the fraternal birth order effect). In several studies comparing gender dysphoric youth, who are likely to be homosexual in adulthood, to clinical or non-clinical control groups, the findings have been consistent with the fraternal birth order effect in males; however, less is known about unique sibship characteristics of gender dysphoric females. The current study investigated birth order and sibling sex ratio in a large sample of children and adolescents referred to the same Gender Identity Service (N = 768). Probands were classified as heterosexual males, homosexual males, or homosexual females based on clinical diagnostic information. Groups differed significantly in age and sibship size, and homosexual females were significantly more likely to be only children. Subsequent analyses controlled for age and for sibship size. Compared to heterosexual males, homosexual males had a significant preponderance of older brothers and homosexual females had a significant preponderance of older sisters. Similarly, the older sibling sex ratio of homosexual males showed a significant excess of brothers whereas that of homosexual females showed a significant excess of sisters. Like previous studies of gender dysphoric youth and adults, these findings were consistent with the fraternal birth order effect. In addition, the greater frequency of only children and elevated numbers of older sisters among the homosexual female group adds to a small literature on sibship characteristics of potential relevance to the development of gender identity and sexual orientation in females.

Digit Ratio (2D:4D): A Biomarker for Prenatal Sex Steroids and Adult Sex Steroids in Challenge Situations.

Science.gov (United States)

Manning, John; Kilduff, Liam; Cook, Christian; Crewther, Blair; Fink, Bernhard

2014-01-01

Digit ratio (2D:4D) denotes the relative length of the second and fourth digits. This ratio is considered to be a biomarker of the balance between fetal testosterone (T) and estrogen (E) in a narrow window of early ontogeny. Evidence for this assertion is derived from direct and indirect measures of prenatal hormonal exposure (in experimental animals, via amniotic fluid samples and in the study of sex-typical traits) in relation to 2D:4D. In contrast, the relationships between 2D:4D and levels of sex steroids in adults are less clear, as many correlational studies of 2D:4D and adult sex steroids have concluded that this association is statistically non-significant. Here, we suggest that in order to understand the link between 2D:4D and sex hormones, one must consider both fetal organizing and adult activating effects of T and E. In particular, we hypothesize that 2D:4D correlates with organizing effects on the endocrine system that moderate activating effects in adulthood. We argue that this is particularly evident in "challenging" conditions such as aggressive and sexual encounters, in which individuals show increased levels of T. We discuss this refinement of the 2D:4D paradigm in relation to the links between 2D:4D and sports performance, and aggression.

XY sex chromosome complement, compared with XX, in the CNS confers greater neurodegeneration during experimental autoimmune encephalomyelitis.

Science.gov (United States)

Du, Sienmi; Itoh, Noriko; Askarinam, Sahar; Hill, Haley; Arnold, Arthur P; Voskuhl, Rhonda R

2014-02-18

Women are more susceptible to multiple sclerosis (MS) and have more robust immune responses than men. However, men with MS tend to demonstrate a more progressive disease course than women, suggesting a disconnect between the severity of an immune attack and the CNS response to a given immune attack. We have previously shown in an MS model, experimental autoimmune encephalomyelitis, that autoantigen-sensitized XX lymph node cells, compared with XY, are more encephalitogenic. These studies demonstrated an effect of sex chromosomes in the induction of immune responses, but did not address a potential role of sex chromosomes in the CNS response to immune-mediated injury. Here, we examined this possibility using XX versus XY bone marrow chimeras reconstituted with a common immune system of one sex chromosomal type. We found that experimental autoimmune encephalomyelitis mice with an XY sex chromosome complement in the CNS, compared with XX, demonstrated greater clinical disease severity with more neuropathology in the spinal cord, cerebellum, and cerebral cortex. A candidate gene on the X chromosome, toll-like receptor 7, was then examined. Toll-like receptor 7 expression in cortical neurons was higher in mice with XY compared with mice with XX CNS, consistent with the known neurodegenerative role for toll-like receptor 7 in neurons. These results suggest that sex chromosome effects on neurodegeneration in the CNS run counter to effects on immune responses, and may bear relevance to the clinical enigma of greater MS susceptibility in women but faster disability progression in men. This is a demonstration of a direct effect of sex chromosome complement on neurodegeneration in a neurological disease.

Adjustment and sex-role orientation in adolescence.

Science.gov (United States)

Lamke, L K

1982-06-01

The purpose of the present study was to reexamine the relationship between sex-role orientation and self-esteem in adolescence. One hundred and six senior high school students completed the Rosenberg self-esteem measure (Rosenberg, 1965) and two measures of sex-role orientation, the Bem Sex Role Inventory, Short Form (BSRI; Bem, 1981), and the Personal Attributes Questionnaire Short Form (PAQ; Spence et al., 1975). The relationship between sex-role orientation and self-esteem was found to vary depending on the sex-role measure employed. Results of the BSRI revealed that androgynous individuals had higher levels of self-esteem than masculine, feminine, and undifferentiated adolescents. PAQ results indicated that androgynous individuals had higher levels of self-esteem than feminine and undifferentiated individuals. When the independent contributions of masculinity and femininity were assessed, both BSRI and PAQ masculinity and femininity significantly predicted self-esteem. Analyses also revealed that the effects of sex-role orientation on self-esteem varied by sex across both the BSRI and PAQ. Implications of the present findings for previous work on sex-role development in adolescence are discussed.

Missing girls in India: infanticide, feticide and made-to-order pregnancies? Insights from hospital-based sex-ratio-at-birth over the last century.

Science.gov (United States)

Sahni, Mohit; Verma, Neeraj; Narula, D; Varghese, Raji Mathew; Sreenivas, V; Puliyel, Jacob M

2008-05-21

There are 44 million missing women in India. Gender bias; neglect of girls, infanticides and feticides are responsible. The sex ratio at birth can be used to examine the influence of antenatal sex selection on the sex ratio. Records from 321,991 deliveries at one hospital over 11 decades were utilized. The middle year in each decade was taken as representative of the decade. Data from 33,524 deliveries were then analyzed. Data for each decade was combined with that of previous decades and compared to the data of subsequent decades to look for any change in the trend. Sex ratio in the second children against sex of the first child was studied separately. The mean sex ratio for the 110 years examined was 910 girls to 1000 boys (95% CI; 891 to 930). The sex ratio dropped significantly from 935 (CI: 905 to 967) before 1979, to 892 (CI: 868 to 918) after 1980 (P = 0.04). The sex ratio in the second child was significantly lower if the first child was a girl [716 (CI: 672 to 762] (Psex ratio fell significantly after 1980 when ultra sound machines for antenatal sex determination became available. The sex ratio in second children if the first was a girl was even lower. Sex selective abortions after antenatal sex determination are thus implicated. However data on second children especially the excess of girls born to mothers who have a previous boy seen in the decade before the advent of antenatal ultra sound machines, suggests that other means of sex selection are also used.

Predictors of unprotected sex among female sex workers in Madagascar: comparing semen biomarkers and self-reported data.

Science.gov (United States)

Gallo, Maria F; Steiner, Markus J; Hobbs, Marcia M; Weaver, Mark A; Hoke, Theresa Hatzell; Van Damme, Kathleen; Jamieson, Denise J; Macaluso, Maurizio

2010-12-01

Research on the determinants of condom use and condom non-use generally has relied on self-reported data with questionable validity. We identified predictors of recent, unprotected sex among 331 female sex workers in Madagascar using two outcome measures: self-reports of unprotected sex within the past 48 h and detection of prostate-specific antigen (PSA), a biological marker of recent semen exposure. Multivariable logistic regression revealed that self-reported unprotected sex was associated with three factors: younger age, having a sipa (emotional partner) in the prior seven days, and no current use of hormonal contraception. The sole factor related to having PSA detected was prevalent chlamydial infection (adjusted odds ratio, 4.5; 95% confidence interval, 2.0-10.1). Differences in predictors identified suggest that determinants of unprotected sex, based on self-reported behaviors, might not correlate well with risk of semen exposure. Caution must be taken when interpreting self-reported sexual behavior measures or when adjusting for them in analyses evaluating interventions for the prevention of HIV/STIs.

Differences in the triglyceride to HDL-cholesterol ratio between Palestinian and Israeli adults.

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Ram Weiss

Full Text Available AIMS: To evaluate differences in the triglyceride to HDL-cholesterol ratio (TG/HDL, thought to be a proxy measure of insulin resistance, between Palestinian and Israeli adults in view of the greater incidence of coronary heart disease and high prevalence of diabetes in Palestinian Arabs. RESEARCH METHODS: A population-based observational prevalence study of cardiovascular and diabetes risk factors in Jerusalem. Participants (968 Palestinians, 707 Israelis, sampled at ages 25-74 years underwent fasting and 2 h post-75 g oral challenge plasma glucose determinations. Metabolic risk was assessed using the surrogate index TG/HDL. Sex-specific comparisons were stratified by categories of body mass index and sex-specific waist circumference quartiles, adjusted by regression for age, glucose tolerance status and use of statins. RESULTS: Prevalence of overweight and obesity was substantially larger in Palestinians (p = 0.005. Prevalence of diabetes was 2.4 and 4 fold higher among Palestinian men and women, respectively (p<0.001. Adjusted TG/HDL was higher in Palestinians than Israelis across BMI and waist circumference categories (p<0.001 for both. Higher TG/HDL in Palestinians persisted in analyses restricted to participants with normal glucose tolerance and off statins. Notably, higher TG/HDL among Palestinians prevailed at a young age (25-44 years and in normal weight individuals of both sexes. CONCLUSIONS: Palestinians have a higher TG/HDL ratio than Israelis. Notably, this is evident also in young, healthy and normal weight participants. These findings indicate the need to study the determinants of this biomarker and other measures of insulin resistance in urban Arab populations and to focus research attention on earlier ages: childhood and prenatal stages of development.

Parallel distribution of sexes within left and right uterine horns in Holstein dairy cows: evidence that the effect of side of pregnancy on sex ratio could be breed-specific in cattle.

Science.gov (United States)

Gharagozlou, F; Vojgani, M; Akbarinejad, V; Niasari-Naslaji, A; Hemmati, M; Youssefi, R

2013-11-30

Dissimilar distribution of male and female calves within left and right uterine horns has been observed in beef cows. A retrospective study was conducted to investigate the effect of side of pregnancy on secondary sex ratio in Holstein dairy cows. Data associated with sex of calves, side of pregnancy, sire, dam, parity number of dam, AI technician, season and year were retrieved from the database of a Holstein dairy farm. In total, data consisted of 6515 birth records from 3155 dams and 244 sires across years 2001-2010. Data were analyzed using logistic regression. There was no difference in proportion of male and female calves between left (52.9% and 47.1%, respectively) and right (53.2% and 46.8%, respectively) uterine horns (P>0.05). AI technician, year, season and parity of dam did not affect secondary sex ratio (P>0.05). Secondary sex ratio of left and right uterine horns, and consequently, overall secondary sex ratio (53.1%) were skewed toward males as compared with hypothetical secondary sex ratio of 50% (Pcows. Copyright © 2013 Elsevier B.V. All rights reserved.

The Facial Width-to-Height Ratio Predicts Sex Drive, Sociosexuality, and Intended Infidelity.

Science.gov (United States)

Arnocky, Steven; Carré, Justin M; Bird, Brian M; Moreau, Benjamin J P; Vaillancourt, Tracy; Ortiz, Triana; Marley, Nicole

2017-09-19

Previous research has linked the facial width-to-height ratio (FWHR) to a host of psychological and behavioral characteristics, primarily in men. In two studies, we examined novel links between FWHR and sex drive. In Study 1, a sample of 145 undergraduate students revealed that FWHR positively predicted sex drive. There were no significant FWHR × sex interactions, suggesting that FWHR is linked to sexuality among both men and women. Study 2 replicated and extended these findings in a sample of 314 students collected from a different Canadian city, which again demonstrated links between the FWHR and sex drive (also in both men and women), as well as sociosexuality and intended infidelity (men only). Internal meta-analytic results confirm the link between FWHR and sex drive among both men and women. These results suggest that FWHR may be an important morphological index of human sexuality.

Does the sex ratio at sexual maturity affect men's later-life mortality risks? Evidence from historical China.

Science.gov (United States)

Zang, Emma; Zheng, Hui

2018-04-01

This study examines the relationship between the male-to-female sex ratio (measured as the proportion male) at sexual maturity and later-life mortality risks in the context of pre-industrial northeast China, using registration data from the Qing Dynasty. We find that a higher male-to-female sex ratio at sexual maturity is associated with a higher later-life mortality risk among men. This association is likely due to the long-term adverse consequences of stress caused by low mate availability at sexual maturity. We further find that a high sex ratio at sexual maturity mitigates the health benefits of marriage and exacerbates the health disadvantages of holding an official position in Qing China. Copyright © 2018 Elsevier Ltd. All rights reserved.

Missing Girls in India: Infanticide, Feticide and Made-to-Order Pregnancies? Insights from Hospital-Based Sex-Ratio-at-Birth over the Last Century

Science.gov (United States)

Sahni, Mohit; Verma, Neeraj; Narula, D.; Varghese, Raji Mathew; Sreenivas, V.; Puliyel, Jacob M.

2008-01-01

Background There are 44 million missing women in India. Gender bias; neglect of girls, infanticides and feticides are responsible. The sex ratio at birth can be used to examine the influence of antenatal sex selection on the sex ratio. Materials and Methods Records from 321,991 deliveries at one hospital over 11 decades were utilized. The middle year in each decade was taken as representative of the decade. Data from 33,524 deliveries were then analyzed. Data for each decade was combined with that of previous decades and compared to the data of subsequent decades to look for any change in the trend. Sex ratio in the second children against sex of the first child was studied separately. Results The mean sex ratio for the 110 years examined was 910 girls to 1000 boys (95% CI; 891 to 930). The sex ratio dropped significantly from 935 (CI: 905 to 967) before 1979, to 892 (CI: 868 to 918) after 1980 (P = 0.04). The sex ratio in the second child was significantly lower if the first child was a girl [716 (CI: 672 to 762] (P<0.001). On the other hand, there was an excess of girls born to mothers whose first child was boy [1140 girls per 1000 boys (CI: 1072 to 1212 P<0.001)]. Conclusions The sex ratio fell significantly after 1980 when ultra sound machines for antenatal sex determination became available. The sex ratio in second children if the first was a girl was even lower. Sex selective abortions after antenatal sex determination are thus implicated. However data on second children especially the excess of girls born to mothers who have a previous boy seen in the decade before the advent of antenatal ultra sound machines, suggests that other means of sex selection are also used. PMID:18493614

Investigating the effect of adjusted DuPont ratio and its components on investor's decisions in short and long term

Directory of Open Access Journals (Sweden)

Parvaneh Khaleghi Kasbi

2014-03-01

Full Text Available This paper investigates the effect of adjusted DuPont ratio and its components on investors’ decisions in short and long term. The primary objective of this study is to find the effect of adjusted DuPont ratio and its components on herding behavior of investors in one and several year period. Hence, 85 corporations as the member of Tehran stock exchange over the period 2006-2011 are selected. In order to recognize the herding, by market index consideration, the herded β and in order to hypothesis validity SPSS software and multivariable linear regression have been used. As the results of this study indicate, the adjusted DuPont ratio and its components have more effect on investors’ decisions in short term but in long the period, the effect of this ratio on herding investors’ behavior are reduced. Furthermore, from the two components of adjusted DuPont ratio, profit margin has more effect on investor's decisions.

A scale on beliefs about children's adjustment in same-sex families: reliability and validity.

Science.gov (United States)

Frias-Navarro, Dolores; Monterde-I-Bort, Hector

2012-01-01

In this study, we developed a new instrument named Scale Beliefs about Children's Adjustment on Same-Sex Families (SBCASSF). The scale was developed to assess of the adults' beliefs about negative impacts on children who are raised by same-sex parents. An initial pool of 95 items was generated by the authors based on a review of the literature on homophobia and feedback from several focus groups. Research findings, based on a sample of 212 university students (mean age 22 years, SD = 8.28), supported the reliability and validity of the scale. The final versions of the SBCASSF included items reflecting the following two factors: individual opposition (α = .87) and normative opposition (α = .88). Convergent validity of the scale is demonstrated by predictable correlations with beliefs about the cause of same-sex sexual orientation and the support for gay and lesbian rights. Our study reveals a strong positive association between high scores on SBCASSF and beliefs that the origin of same-sex sexual orientation is learned and opposition to gay and lesbian rights.

Sex Ratio And Size At First Maturity Of Blue Swimming Crab (Portunus pelagicus Salemo Island Pangkep Regency

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Muh. Saleh Nurdin

2016-03-01

Full Text Available Blue swimming crab (Portunuspelagicus is aeconomical valuable fisheries importantcommodity  due to the high demand and availability jobs created for the fishermen. Due to their high demand blue swimming crab heavily exploited from Salemo Island. This study aimed at comparing the sex ratio and the size at first maturity of blue swimming crab caught in mangrove ecosystems, coral reefs, and seagrass. Sex ratio was analyzed using chi square test and the size at first maturity was analyzed using the Spearman-Karber formula. The results showed the sex ratio ofmales and femalessmall crab caught in every ecosystem is balanced. The size at first maturity of blue swimming crab caught in mangrove, seagrass and coral reefs, each to the male 81,08 mm, 102,36 mm and 102,87 mm in width and size of female 94,54 mm, 83,35 mm, 98,31 mm width. In a reference to government regulations, the blue male swimming crab caught in the coral reef and seagrass ecosystems have yet to size at first maturity is allowed to be captured. Keywords: blue swimming crab, sex ratio,size at first maturity, Salemo Island

The Effects of Sex-Ratio and Density on Locomotor Activity in the House Fly, Musca domestica

OpenAIRE

Bahrndorff, Simon; Kjærsgaard, Anders; Pertoldi, Cino; Loeschcke, Volker; Schou, Toke M.; Skovgård, Henrik; Hald, Birthe

2012-01-01

Although locomotor activity is involved in almost all behavioral traits, there is a lack of knowledge on what factors affect it. This study examined the effects of sex-ratio and density on the circadian rhythm of locomotor activity of adult Musca domestica L. (Diptera: Muscidae) using an infra-red light system. Sex-ratio significantly affected locomotor activity, increasing with the percentage of males in the vials. In accordance with other studies, males were more active than females, but th...

Marriage season, promptness of successful pregnancy and first-born sex ratio in a historical natural fertility population - evidence for sex-dependent early pregnancy loss?

Science.gov (United States)

Nonaka, K.; Desjardins, Bertrand; Charbonneau, Hubert; Légaré, Jacques; Miura, Teiji

We investigated population-based vital records of the seventeenth and eighteenth century French Canadian population to assess the effects of marriage season on the outcome of the first births under natural fertility conditions (n=21,698 marriages). Promptness of the first successful conception after marriage differed according to marriage season; the proportion of marriages with a marriage-first birth interval of 8.0-10.0 months was lowest (34%) for marriages in August-October (P=0.001). Although the male/female sex ratio of the babies born with an interval of 8.0-10.0 months was generally higher (1.10) than those with an interval of 10.0-24.0 months (1.05), the marriages in August-October resulted in a significantly reduced sex ratio (0.96) among only the prompt conceptions (P=0.026). We discuss whether this seasonal reduction of the sex ratio could be partly explained by a clustered pregnancy loss of male zygotes in early pregnancy.

The effects of sex-ratio and density on locomotor activity in the house fly, Musca domestica

DEFF Research Database (Denmark)

Bahrndorff, Simon; Kjaersgaard, Anders; Pertoldi, Cino

2012-01-01

Although locomotor activity is involved in almost all behavioral traits, there is a lack of knowledge on what factors affect it. This study examined the effects of sex-ratio and density on the circadian rhythm of locomotor activity of adult Musca domestica L. (Diptera: Muscidae) using an infra......-red light system. Sex-ratio significantly affected locomotor activity, increasing with the percentage of males in the vials. In accordance with other studies, males were more active than females, but the circadian rhythm of the two sexes was not constant over time and changed during the light period...... of the behavioral interactions between houseflies and highlight the importance of these factors when designing behavioral experiments using M. domestica....

Is the sex hormone binding globulin related to preeclampsia independent of insulin resistance

International Nuclear Information System (INIS)

Rahmanian, M.; Salari, Z.; Mirmohammadkhani, M.; Ghorbani, R.

2014-01-01

Objective: To evaluate the association between Sex Hormone Binding Globulin and preeclampsia in Iranian women considering the probable confounding effect of insulin resistance. Methods: The case-control study was conducted at the Semnan University of Medical Sciences, Iran, and comprised pregnant women who received prenatal care at Amiralmomenin Hospital in 2011. Cases represented patients admitted because of preeclampsia, while controls were randomly selected eligible pregnant women without hypertension and/or proteinuria. Fasting blood sugar and insulin were assessed for all participants as well as their blood concentration of Sex Hormone Binding Globulin. The Homeostasis Model Assessment of Insulin Resistance Score was used. The correlation between dependant and independent variables was reported by crude and adjusted odds ratio applying logistic regression models. SPSS 16.0 was used for statistical analysis. Results: Of the 100 pregnant women in the study, 45(45%) were cases. Insulin resistance was found to be significantly more frequent in the cases compared to the controls (adjusted odds ratio=2.78; 95% Confidence Interval: 1.11, 6.90; p<0.01). There was a significant reverse correlation between level of Sex Hormone Binding Globulin in blood and being a case of preeclampsia (adjusted odds ratio=0.99; 95% Confidence Interval: 0.98, 1.00; p=0.04). Conclusion: Independent of insulin resistance, every 1nmol/l increase in Sex Hormone Binding Globulin, decreases the odds of preeclampsia by 1%, notifying Sex Hormone Binding Globulin as an important biomarker about its etiology and prediction. (author)

Birth order and sibling sex ratio of children and adolescents referred to a gender identity service.

Directory of Open Access Journals (Sweden)

Doug P Vanderlaan

Full Text Available In adult male samples, homosexuality is associated with a preponderance of older brothers (i.e., the fraternal birth order effect. In several studies comparing gender dysphoric youth, who are likely to be homosexual in adulthood, to clinical or non-clinical control groups, the findings have been consistent with the fraternal birth order effect in males; however, less is known about unique sibship characteristics of gender dysphoric females. The current study investigated birth order and sibling sex ratio in a large sample of children and adolescents referred to the same Gender Identity Service (N = 768. Probands were classified as heterosexual males, homosexual males, or homosexual females based on clinical diagnostic information. Groups differed significantly in age and sibship size, and homosexual females were significantly more likely to be only children. Subsequent analyses controlled for age and for sibship size. Compared to heterosexual males, homosexual males had a significant preponderance of older brothers and homosexual females had a significant preponderance of older sisters. Similarly, the older sibling sex ratio of homosexual males showed a significant excess of brothers whereas that of homosexual females showed a significant excess of sisters. Like previous studies of gender dysphoric youth and adults, these findings were consistent with the fraternal birth order effect. In addition, the greater frequency of only children and elevated numbers of older sisters among the homosexual female group adds to a small literature on sibship characteristics of potential relevance to the development of gender identity and sexual orientation in females.

Flight patterns and sex ratio of beetles of the subfamily Dynastinae (Coleoptera, Melolonthidae

Directory of Open Access Journals (Sweden)

Larissa Simões Corrêa de Albuquerque

2016-09-01

Full Text Available ABSTRACT Dynastinae is one of the most representative subfamilies of Melolonthidae (Scarabaeoidea and has considerable ecological importance due mainly to interactions with plants of the families Araceae and Annonaceae. This relationship has led to the evolution of nocturnal activity patterns, which are influenced by environmental conditions. In the present study, abiotic factors were investigated to comprehend the influence on the flight patterns and identify the sex ratio of beetles from this subfamily. A study was conducted at Campo de Instrução Marechal Newton Cavalcanti in northeastern Brazil between December 2010 and November 2011. Thirteen species of Dynastinae were identified, most of which were from the genus Cyclocephala. Abundance and richness were greater in the dry season. Six species exhibited peak flight activity at specific periods of the night. More females than males were recorded for Cyclocephala distincta and C. paraguayensis. The present findings suggest that rainfall reduces the flight activity of these beetles and different time schedules may be related to mating behavior, foraging behavior and the avoidance of interspecific resource competition.

Effect of Corticosterone and Hen Body Mass on Primary Sex Ratio in Laying Hen (Gallusgallus), Using Unincubated Eggs1

NARCIS (Netherlands)

Aslam, M.A.; Groothuis, T.G.G.; Smits, M.A.; Woelders, H.

2014-01-01

In various studies, chronic elevation of corticosterone levels in female birds under natural or experimental conditions resulted in female biased offspring sex ratios. In chicken, one study with injected corticosterone resulted in a male sex ratio bias. In the current study, we chronically elevated

Effect of corticosterone and hen body mass on primary sex ratio in laying hen (Gallus gallus), using unincubated eggs

NARCIS (Netherlands)

Aslam, Muhammad Aamir; Groothuis, Ton G. G.; Smits, Mari A.; Woelders, Henri

In various studies, chronic elevation of corticosterone levels in female birds under natural or experimental conditions resulted in female biased offspring sex ratios. In chicken, one study with injected corticosterone resulted in a male sex ratio bias. In the current study, we chronically elevated

Postzygotic incompatibilities between the pupfishes, Cyprinodon elegans and Cyprinodon variegatus: hybrid male sterility and sex ratio bias.

Science.gov (United States)

Tech, C

2006-11-01

I examined the intrinsic postzygotic incompatibilities between two pupfishes, Cyprinodon elegans and Cyprinodon variegatus. Laboratory hybridization experiments revealed evidence of strong postzygotic isolation. Male hybrids have very low fertility, and the survival of backcrosses into C. elegans was substantially reduced. In addition, several crosses produced female-biased sex ratios. Crosses involving C. elegans females and C. variegatus males produced only females, and in backcrosses involving hybrid females and C. elegans males, males made up approximately 25% of the offspring. All other crosses produced approximately 50% males. These sex ratios could be explained by genetic incompatibilities that occur, at least in part, on sex chromosomes. Thus, these results provide strong albeit indirect evidence that pupfish have XY chromosomal sex determination. The results of this study provide insight on the evolution of reproductive isolating mechanisms, particularly the role of Haldane's rule and the 'faster-male' theory in taxa lacking well-differentiated sex chromosomes.

Associations Between Sex Education and Contraceptive Use Among Heterosexually Active, Adolescent Males in the United States.

Science.gov (United States)

Jaramillo, Nicole; Buhi, Eric R; Elder, John P; Corliss, Heather L

2017-05-01

This study examined associations between reports of receiving education on topics commonly included in sex education (e.g., abstinence only, comprehensive) prior to age 18 years and contraceptive use at the last sex among heterosexually active, 15- to 20-year-old males in the United States. Cross-sectional data from 539 males participating in the 2011-2013 National Survey of Family Growth were analyzed. Bivariate and multinomial logistic regression analyses adjusting for confounding estimated associations between receipt of seven sex education topics (e.g., information on HIV/AIDS, how to say no to sex) and contraceptive use at the last sex (i.e., dual barrier and female-controlled effective methods, female-controlled effective method only, barrier method only, and no method). Nearly, all participants (99%) reported receiving sex education on at least one topic. Education on sexually transmitted diseases (94.7%) and HIV/AIDS (92.0%) were the most commonly reported topics received; education on where to get birth control was the least common (41.6%). Instruction about birth control methods (adjusted odds ratio [AOR] = 3.01; 95% confidence interval [CI] = 1.32-6.87) and how to say no to sex (AOR = 3.39; CI = 1.33-8.64) were positively associated with dual contraception compared to no use. For each additional sex education topic respondents were exposed to, their odds of using dual methods compared to no method was 47% greater (AOR = 1.47; CI = 1.16-1.86). Exposure to a larger number of sex education topics is associated with young men's report of dual contraception use at the last sex. Comprehensive sex education, focusing on a range of topics, may be most effective at promoting safer sex among adolescent males. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Induction of inherited sterility and sex ratio distribution due to exposure to substerilising doses of gamma radiation in cotton bollworm Earias vittella fabricius

International Nuclear Information System (INIS)

Tamhankar, A.J.; Shantharam, K.

2005-01-01

Substerilising doses of gamma radiation induced inherited sterility and sex ratio distortion in the cotton bollworm Earias vittella fabricius. Adults irradiated with 75 Gy and self-crossed, provided sterile F 1 adults, suitable for direct use in sterile insect technique (SIT). In case of 50 Gy, the F 1 adults, when backcrossed, produced F 2 progeny with sex ratio in favour of females (1: >3). With 25 Gy, a sex ratio distortion was recorded in F 1 (1 male: 2.25 females) and self-crossing of F 1 resulted in progeny with a sex ratio of 3:1. Backcrossing of the F 1 female produced F 2 progeny with a sex ratio of 1:5. These results have implications in improving cost/benefit ratio of SIT for this species. (author)

Sex-ratio biasing towards daughters among lower-ranking co-wives in Rwanda

NARCIS (Netherlands)

Pollet, Thomas V.; Fawcett, Tim W.; Buunk, Abraham P.; Nettle, Daniel

2009-01-01

There is considerable debate as to whether human females bias the sex ratio of their offspring as a function of their own condition. We apply the Trivers-Willard prediction-that mothers in poor condition will overproduce daughters-to a novel measure of condition, namely wife rank within a polygynous

Brood size and sex ratio in response to host quality and wasp traits in the gregarious parasitoid Oomyzus sokolowskii (Hymenoptera: Eulophidae

Directory of Open Access Journals (Sweden)

Xianwei Li

2017-01-01

Full Text Available This laboratory study investigated whether the larval-pupal parasitoid Oomyzus sokolowskii females adjust their brood size and sex ratio in response to body size and stage of Plutella xylostella larval hosts, as well as to their own body size and the order of oviposition. These factors were analyzed using multiple regression with simultaneous entry of them and their two-way interactions. Parasitoids brood size tended to increase with host body size at parasitism when the 4th instar larval host was attacked, but did not change when the 2nd and 3rd instar larvae were attacked. Parasitoids did not vary in brood size according to their body size, but decreased with their bouts of oviposition on a linear trend from 10 offspring adults emerged per host in the first bout of oviposition down to eight in the third. Parasitoid offspring sex ratio did not change with host instar, host body weight, wasp body size, and oviposition bout. Proportions of male offspring per brood were from 11% to 13% from attacking the 2nd to 4th instar larvae and from 13% to 16% across three successive bouts of oviposition, with a large variation for smaller host larvae and wasps. When fewer than 12 offspring were emerged from a host, one male was most frequently produced; when more than 12 offspring were emerged, two or more males were produced. Our study suggests that O. sokolowskii females may optimize their clutch size in response to body size of mature P. xylostella larvae, and their sex allocation in response to clutch size.

Sex Determination, Sex Ratios, and Genetic Conflict

NARCIS (Netherlands)

Werren, John H.; Beukeboom, Leo W.

1998-01-01

Genetic mechanisms of sex determination are unexpectedly diverse and change rapidly during evolution. We review the role of genetic conflict as the driving force behind this diversity and turnover. Genetic conflict occurs when different components of a genetic system are subject to selection in

Comparative AFLP reveals paternal sex ratio chromosome specific DNA sequences in the parasitoid wasp Trichogramma kaykai

NARCIS (Netherlands)

Vugt, van J.J.F.A.; Hulst, van der R.G.M.; Pruijssers, A.; Verbaarschot, P.G.H.; Stouthamer, R.; Jong, de H.

2009-01-01

The parasitoid wasp Trichogramma kaykai with a haplo-diploid sex determination has a B chromosome called the paternal sex ratio (PSR) chromosome that confers paternal genome loss during early embryogenesis, resulting in male offspring. So far, it is not well known whether the PSR chromosome has

Common vole (Microtus arvalis) population sex ratio: biases and process variation

Czech Academy of Sciences Publication Activity Database

Bryja, Josef; Nesvadbová, Jiřina; Heroldová, Marta; Jánová, Eva; Losík, J.; Trebatická, L.; Tkadlec, Emil

2005-01-01

Roč. 83, č. 11 (2005), s. 1391-1399 ISSN 0008-4301 R&D Projects: GA ČR(CZ) GA524/01/1316; GA ČR(CZ) GP206/02/P068; GA ČR(CZ) GA206/04/2003 Institutional research plan: CEZ:AV0Z60930519 Keywords : common vole * population sex ratio Subject RIV: EH - Ecology, Behaviour Impact factor: 1.175, year: 2005

Sex Differences in Mortality Based on United Network for Organ Sharing Status While Awaiting Heart Transplantation.

Science.gov (United States)

Hsich, Eileen M; Blackstone, Eugene H; Thuita, Lucy; McNamara, Dennis M; Rogers, Joseph G; Ishwaran, Hemant; Schold, Jesse D

2017-06-01

There are sex differences in mortality while awaiting heart transplantation, and the reason remains unclear. We included all adults in the Scientific Registry of Transplant Recipients placed on the heart transplant active waitlist from 2004 to 2015. The primary end point was all-cause mortality. Multivariable Cox proportional hazards models were performed to evaluate survival by United Network for Organ Sharing (UNOS) status at the time of listing. Random survival forest was used to identify sex interactions for the competing risk of death and transplantation. There were 33 069 patients (25% women) awaiting heart transplantation. This cohort included 7681 UNOS status 1A (26% women), 13 027 UNOS status 1B (25% women), and 12 361 UNOS status 2 (26% women). During a median follow-up of 4.3 months, 1351 women and 4052 men died. After adjusting for >20 risk factors, female sex was associated with a significant risk of death among UNOS status 1A (adjusted hazard ratio, 1.14; 95% confidence interval, 1.01-1.29) and UNOS status 1B (adjusted hazard ratio, 1.17; 95% confidence interval, 1.05-1.30). In contrast, female sex was significantly protective for time to death among UNOS status 2 (adjusted hazard ratio, 0.85; 95% confidence interval, 0.76-0.95). Sex differences in probability of transplantation were present for every UNOS status, and >20 sex interactions were identified for mortality and transplantation. When stratified by initial UNOS status, women had a higher mortality than men as UNOS status 1 and a lower mortality as UNOS status 2. With >20 sex interactions for mortality and transplantation, further evaluation is warranted to form a more equitable allocation system. © 2017 American Heart Association, Inc.

Coping, goal adjustment, and psychological well-being in HIV-infected men who have sex with men

NARCIS (Netherlands)

Kraaij, Vivian; der Veek, Shelley M.C.; Garnefski, Nadia; Schroevers, Maya; Witlox, Robert; Maes, Stan

2008-01-01

The relationships between coping strategies, goal adjustment, and symptoms of depression and anxiety were studied in 104 HIV-positive men who have sex with men, in December 2006. The mean age of the respondents was 50 years, and almost were of Dutch nationality. On average people had known about

The paternal-sex-ratio (PSR) chromosome in natural populations of Nasonia (Hymenoptera Chalcidoidea)

NARCIS (Netherlands)

Beukeboom, L.W.; Werren, J.H.

2000-01-01

Selfish genetic elements may be important in promoting evolutionary change. Paternal sex ratio (PSR) is a selfish B chromosome that causes all-male families in the haplodiploid parasitic wasp Nasonia vitripennis, by inducing paternal genome loss in fertilized eggs. The natural distribution and

Beyond anal sex: sexual practices associated with HIV risk reduction among men who have sex with men in Boston, Massachusetts.

Science.gov (United States)

Reisner, Sari L; Mimiaga, Matthew J; Skeer, Margie; Mayer, Kenneth H

2009-07-01

Men who have sex with men (MSM) continue to bear a disproportionate HIV and sexually transmitted disease (STD) burden. The current study examined the frequency and associations of sexual risk reduction behaviors among a sample of MSM in the greater Boston, Massachusetts area. One hundred eighty-nine MSM completed a one-time behavioral and psychosocial assessment between March 2006 and May 2007. Logistic regression procedures examined the association of demographic, psychosocial, and behavioral factors with risk reduction practices. Twenty percent of the sample reported rimming, mutual masturbation, digital penetration, using sex toys, or 100% condom use as a means to reduce their risk of acquiring or transmitting HIV in the prior 12 months. In bivariate analyses, risk reducers were more likely to disclose their MSM status (i.e., be "out"; odds ratio [OR] = 3.64; p < 0.05), and report oral sex with a condom in the prior 12 months (OR = 4.85; p < 0.01). They were less likely to report: depression (Center for Epidemiologic Studies Depression Scale [CES-D] score 16+; OR = 0.48; p < 0.05), a history of one or more sexually transmitted diseases (STDs; OR = 0.40; p < 0.05), and meeting sexual partners at public cruising areas (OR = 0.32; p < 0.01). In a multivariable model, risk reducers were less likely to report: alcohol use during sex (adjusted odds ratio [AOR] = 0.33; p < 0.05), depression (CESD score 16+; AOR = 0.32; p < 0.05), or meeting sexual partners at public cruising areas (AOR = 0.30; p < 0.05), or via the Internet (AOR = 0.12; p < 0.05) in the previous 12 months. Identifying and understanding such factors associated with risk reduction behaviors may be important to consider in designing effective prevention interventions to promote sexual health for MSM.

Sex ratio at birth and racial differences: Why do Black women give ...

African Journals Online (AJOL)

The two important questions that this paper will attempt to answer are: (1) why is it that regardless of race/ethnicity or geographic location, the sex ratio data at birth show more males than females?; and (2) Why is it that regardless of geographic location compared to other racial/ethnic groups, Black women or Women of ...

Establishing sex ratios of sea turtle foraging populations: validation of a novel testosterone hormone assay technology and sex assessment for five species.

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Demographic data are essential for developing sound management and conservation plans for marine turtle populations. Sex ratios, even though they are an essential...

Seasonal Sex Ratio Trend in the European Kestrel : An Evolutionarily Stable Strategy Analysis

NARCIS (Netherlands)

Pen, I.R.; Weissing, F.J.; Daan, S.

We present an evolutionarily stable strategy (ESS) model to analyze selection on seasonal variation in the brood sex ratio, as observed in several species of raptorial birds. The model is specifically tailored to the life history of the European kestrel, and it reflects the maturation time

Regulation of gonadal sex ratios and pubertal development by the thyroid endocrine system in zebrafish (Danio rerio).

Science.gov (United States)

Sharma, Prakash; Patiño, Reynaldo

2013-04-01

We examined associations between thyroid condition, gonadal sex and pubertal development in zebrafish. Seventy-two-hour postfertilization larvae were reared in untreated medium or in the presence of goitrogens (sodium perchlorate, 0.82 mM; methimazole, 0.15 and 0.3 mM) or thyroxine (1 and 10 nM) for 30 days. Thyrocyte height, gonadal sex and gonadal development were histologically determined at 45 and 60 days postfertilization (dpf). Thyrocyte hypertrophy, an index of hypothyroidism, was observed at 45 and 60 dpf in perchlorate-treated but only at 45 dpf in methimazole-treated fish. Similarly, gonadal sex ratios were biased toward ovaries relative to control animals at 45 and 60 dpf in perchlorate-treated fish but only at 45 dpf in methimazole-treated fish. Gonadal sex ratios were biased toward testes at 45 and 60 dpf in thyroxine-treated fish. Spermatogenesis was delayed in testes from goitrogen-treated fish at 60 dpf relative to control values, but was unaffected in testes from thyroxine-treated individuals. Oogenesis seemed to be nonspecifically delayed in all treatments relative to control at 60 dpf. This study confirmed the previously reported association between hypothyroid condition and ovarian-skewed ratios, and hyperthyroid condition and testicular-skewed ratios, and also showed that male pubertal development is specifically delayed by experimental hypothyroidism. The simultaneous recovery from the hypothyroid and ovary-inducing effects of methimazole by 60 dpf (27 days post-treatment) suggests that the ovary-skewing effect of goitrogens is reversible when thyroid conditions return to basal levels before developmental commitment of gonadal sex. Conversely, the masculinizing effect of hyperthyroidism seems to be stable and perhaps permanent. Published by Elsevier Inc.

Regulation of gonadal sex ratios and pubertal development by the thyroid endocrine system in zebrafish (Danio rerio)

Science.gov (United States)

Sharma, Prakash; Patino, Reynaldo

2013-01-01

We examined associations between thyroid condition, gonadal sex and pubertal development in zebrafish. Seventy-two-hour postfertilization larvae were reared in untreated medium or in the presence of goitrogens (sodium perchlorate, 0.82 mM; methimazole, 0.15 and 0.3 mM) or thyroxine (1 and 10 nM) for 30 days. Thyrocyte height, gonadal sex and gonadal development were histologically determined at 45 and 60 days postfertilization (dpf). Thyrocyte hypertrophy, an index of hypothyroidism, was observed at 45 and 60 dpf in perchlorate-treated but only at 45 dpf in methimazole-treated fish. Similarly, gonadal sex ratios were biased toward ovaries relative to control animals at 45 and 60 dpf in perchlorate-treated fish but only at 45 dpf in methimazole-treated fish. Gonadal sex ratios were biased toward testes at 45 and 60 dpf in thyroxine-treated fish. Spermatogenesis was delayed in testes from goitrogen-treated fish at 60 dpf relative to control values, but was unaffected in testes from thyroxine-treated individuals. Oogenesis seemed to be nonspecifically delayed in all treatments relative to control at 60 dpf. This study confirmed the previously reported association between hypothyroid condition and ovarian-skewed ratios, and hyperthyroid condition and testicular-skewed ratios, and also showed that male pubertal development is specifically delayed by experimental hypothyroidism. The simultaneous recovery from the hypothyroid and ovary-inducing effects of methimazole by 60 dpf (27 days post-treatment) suggests that the ovary-skewing effect of goitrogens is reversible when thyroid conditions return to basal levels before developmental commitment of gonadal sex. Conversely, the masculinizing effect of hyperthyroidism seems to be stable and perhaps permanent.

Differences in the Triglyceride to HDL-Cholesterol Ratio between Palestinian and Israeli Adults

Science.gov (United States)

Weiss, Ram; Nassar, Hisham; Sinnreich, Ronit; Kark, Jeremy D.

2015-01-01

Aims To evaluate differences in the triglyceride to HDL-cholesterol ratio (TG/HDL), thought to be a proxy measure of insulin resistance, between Palestinian and Israeli adults in view of the greater incidence of coronary heart disease and high prevalence of diabetes in Palestinian Arabs. Research Methods A population-based observational prevalence study of cardiovascular and diabetes risk factors in Jerusalem. Participants (968 Palestinians, 707 Israelis, sampled at ages 25-74 years) underwent fasting and 2h post-75g oral challenge plasma glucose determinations. Metabolic risk was assessed using the surrogate index TG/HDL. Sex-specific comparisons were stratified by categories of body mass index and sex-specific waist circumference quartiles, adjusted by regression for age, glucose tolerance status and use of statins. Results Prevalence of overweight and obesity was substantially larger in Palestinians (p = 0.005). Prevalence of diabetes was 2.4 and 4 fold higher among Palestinian men and women, respectively (psexes. Conclusions Palestinians have a higher TG/HDL ratio than Israelis. Notably, this is evident also in young, healthy and normal weight participants. These findings indicate the need to study the determinants of this biomarker and other measures of insulin resistance in urban Arab populations and to focus research attention on earlier ages: childhood and prenatal stages of development. PMID:25635396

Prevalence and structural correlates of gender based violence among a prospective cohort of female sex workers.

Science.gov (United States)

Shannon, Kate; Kerr, T; Strathdee, S A; Shoveller, J; Montaner, J S; Tyndall, M W

2009-08-11

To examine the prevalence and structural correlates of gender based violence against female sex workers in an environment of criminalised prostitution. Prospective observational study. Vancouver, Canada during 2006-8. Female sex workers 14 years of age or older (inclusive of transgender women) who used illicit drugs (excluding marijuana) and engaged in street level sex work. Self reported gender based violence. Of 267 female sex workers invited to participate, 251 women returned to the study office and consented to participate (response rate of 94%). Analyses were based on 237 female sex workers who completed a baseline visit and at least one follow-up visit. Of these 237 female sex workers, 57% experienced gender based violence over an 18 month follow-up period. In multivariate models adjusted for individual and interpersonal risk practices, the following structural factors were independently correlated with violence against female sex workers: homelessness (adjusted odds ratio for physical violence (aOR(physicalviolence)) 2.14, 95% confidence interval 1.34 to 3.43; adjusted odds ratio for rape (aOR(rape)) 1.73, 1.09 to 3.12); inability to access drug treatment (adjusted odds ratio for client violence (aOR(clientviolence)) 2.13, 1.26 to 3.62; aOR(physicalviolence) 1.96, 1.03 to 3.43); servicing clients in cars or public spaces (aOR(clientviolence) 1.50, 1.08 to 2.57); prior assault by police (aOR(clientviolence) 3.45, 1.98 to 6.02; aOR(rape) 2.61, 1.32 to 5.16); confiscation of drug use paraphernalia by police without arrest (aOR(physicalviolence) 1.50, 1.02 to 2.41); and moving working areas away from main streets owing to policing (aOR(clientviolence) 2.13, 1.26 to 3.62). Our results demonstrate an alarming prevalence of gender based violence against female sex workers. The structural factors of criminalisation, homelessness, and poor availability of drug treatment independently correlated with gender based violence against street based female sex workers. Socio

Sex Ratios, Economic Power, and Women's Roles: A Theoretical Extension and Empirical Test.

Science.gov (United States)

South, Scott J.

1988-01-01

Tested hypotheses concerning sex ratios, women's roles, and economic power with data from 111 countries. Found undersupply of women positively associated with proportion of women who marry and fertility rate; inversely associated with women's average age at marriage, literacy rate, and divorce rate. Suggests women's economic power may counteract…

Mixture Analysis and Mammalian Sex Ratio Among Middle Pleistocene Mouflon of Arago Cave, France

Science.gov (United States)

Monchot, Hervé

1999-09-01

In archaeological studies, it is often important to be able assess sexual dimorphism and sex ratios in populations. Obtaining sex ratio is easy if each individual in the population can be accurately sexed through the use of one more objective variables. But this is often impossible, due to incompleteness of the osteological record. A modern statistical approach to handle this problem is Mixture Analysis using the method of maximum likelihood. It consists of determining how many groups are present in the sample, two in this case, in which proportions they occur, and to estimate the parameters accordingly. This paper shows the use of this method on vertebrate fossil populations in a prehistoric context with implications on prey acquisition by early humans. For instance, the analysis of mouflon bones from Arago cave (Tautavel, France) indicates that there are more females than males in the F layer. According to the ethology of the animal, this indicates that the hunting strategy could be the result of selective choice of the prey. Moreover, we may deduce the presence of Anteneandertalians on the site during spring and summer periods.

Auger electron spectroscopy for the determination of sex and age related Ca/P ratio at different bone sites

International Nuclear Information System (INIS)

Balatsoukas, Ioannis; Kourkoumelis, Nikolaos; Tzaphlidou, Margaret

2010-01-01

The Ca/P ratio of normal cortical and trabecular rat bone was measured by Auger electron spectroscopy (AES). Semiquantitative analysis was carried out using ratio techniques to draw conclusions on how age, sex and bone site affect the relative composition of calcium and phosphorus. Results show that Ca/P ratio is not sex dependent; quite the opposite, bone sites exhibit variations in elemental stoichiometry where femoral sections demonstrate higher Ca/P ratio than rear and front tibias. Age-related changes are more distinct for cortical bone in comparison with the trabecular bone. The latter's Ca/P ratio remains unaffected from all the parameters under study. This study confirms that AES is able to successfully quantify bone mineral main elements when certain critical points, related to the experimental conditions, are addressed effectively.

Basel III : how have banks adjusted to increase CET1 ratios?

OpenAIRE

Bjerketvedt, Oda; Arneberg-Bauer, Tonje

2013-01-01

In 2010 the Basel Committee finalised the global framework called Basel III, which will have a significant impact on the global banking sector. A large part of the framework focuses on capital adequacy, where the Common Equity Tier 1 (CET1) ratio is essential. Through an analysis of four banks from the United Kingdom – HSBC, Barclays, Lloyds Banking Group and Standard Chartered – this thesis aim to examine how these banks have adjusted to the new CET1 requirements. In the EU the Basel III ...

Resource Elasticity of Offspring Survival and the Optimal Evolution of Sex Ratios

Science.gov (United States)

Wang, Rui-Wu; Wang, Ya-Qiang; He, Jun-Zhou; Li, Yao-Tang

2013-01-01

The fitness of any organisms includes the survival and reproductive rate of adults and the survival of their offspring. Environmental selection pressures might not affect these two aspects of an organism equally. Assuming that an organism first allocates its limited resources to maintain its survival under environmental selection pressure, our model, based on the evolutionarily stable strategy theory, surprisingly shows that the sex ratio is greatly affected by the environmental pressure intensity and by the reproductive resource elasticity of offspring survival. Moreover, the concept of the resource elasticity of offspring survival intrinsically integrates the ecological concepts of K selection and r selection. The model shows that in a species with reproductive strategy K, increased environmental selection pressure will reduce resource allocation to the male function. By contrast, in a species with reproductive strategy r, harsher environmental selection pressure will increase allocation to the male function. The elasticity of offspring survival might vary not only across species, but also across many other factors affecting the same species (e.g., age structure, spatial heterogeneity), which explains sex ratio differences across species or age structures and spatial heterogeneity in the same species. PMID:23468826

First Assessment of the Sex Ratio for an East Pacific Green Sea Turtle Foraging Aggregation: Validation and Application of a Testosterone ELISA.

Directory of Open Access Journals (Sweden)

Camryn D Allen

Full Text Available Determining sex ratios of endangered populations is important for wildlife management, particularly species subject to sex-specific threats or that exhibit temperature-dependent sex determination. Sea turtle sex is determined by incubation temperature and individuals lack external sex-based traits until sexual maturity. Previous research utilized serum/plasma testosterone radioimmunoassays (RIA to determine sex in immature/juvenile sea turtles. However, there has been a growing application of enzyme-linked immunosorbent assay (ELISA for wildlife endocrinology studies, but no study on sea turtles has compared the results of ELISA and RIA. This study provides the first sex ratio for a threatened East Pacific green sea turtle (Chelonia mydas foraging aggregation, a critical step for future management of this species. Here, we validate a testosterone ELISA and compare results between RIA and ELISA of duplicate samples. The ELISA demonstrated excellent correspondence with the RIA for providing testosterone concentrations for sex determination. Neither assay proved reliable for predicting the sex of reproductively active females with increased testosterone production. We then applied ELISA to examine the sex ratio of 69 green turtles foraging in San Diego Bay, California. Of 45 immature turtles sampled, sex could not be determined for three turtles because testosterone concentrations fell between the ranges for either sex (females: 4.1-113.1 pg/mL, males: 198.4-2,613.0 pg/mL and these turtles were not subsequently recaptured to enable sex determination; using a Bayesian model to predict probabilities of turtle sex we predicted all three 'unknowns' were female (> 0.86. Additionally, the model assigned all turtles with their correct sex (if determined at recapture with 100% accuracy. Results indicated a female bias (2.83F:1M among all turtles in the aggregation; when focusing only on putative immature turtles the sex ratio was 3.5F:1M. With appropriate

Differential timing and latitudinal variation in sex ratio of Aquatic Warblers during the autumn migration

Science.gov (United States)

Wojczulanis-Jakubas, Katarzyna; Chrostek, Małgorzata E.; Jiguet, Frédéric; Martínez, Carlos Zumalacárregui; Miguélez, David; Neto, Júlio M.

2017-12-01

Differential migration has been extensively reported in spring, but less so in autumn, particularly in relation to sex in monomorphic bird species. Here, we analysed the autumn passage of a monomorphic, globally threatened passerine, the Aquatic Warbler Acrocephalus paludicola throughout Western Europe, with regard to age and sex. We showed that, overall, adults migrated earlier than first-year birds, and males migrated earlier than females during the autumn migration. This may be caused by an overall social dominance of adults over immatures, and differentiated migration strategy of males and females. In addition, we found male-skewed sex proportions, with a tendency to an equalised ratio in more southern stopover sites. This may indicate a male bias in the global population or different migration strategies of the sexes. Differential migration may cause the age and sex classes to be exposed differently to various threats affecting demographic structure of the species.

Haldane’s Rule Is Linked to Extraordinary Sex Ratios and Sperm Length in Stalk-Eyed Flies

Science.gov (United States)

Wilkinson, Gerald S.; Christianson, Sarah J.; Brand, Cara L.; Ru, George; Shell, Wyatt

2014-01-01

We use three allopatric populations of the stalk-eyed fly Teleopsis dalmanni from Southeast Asia to test two predictions made by the sex chromosome drive hypothesis for Haldane’s rule. The first is that modifiers that suppress or enhance drive should evolve rapidly and independently in isolated populations. The second is that drive loci or modifiers should also cause sterility in hybrid males. We tested these predictions by assaying the fertility of 2066 males derived from backcross experiments involving two pairs of populations and found that the proportion of mated males that fail to produce any offspring ranged from 38 to 60% among crosses with some males producing strongly female-biased or male-biased sex ratios. After genotyping each male at 25–28 genetic markers we found quantitative trait loci (QTL) that jointly influence male sterility, sperm length, and biased progeny sex ratios in each pair of populations, but almost no shared QTL between population crosses. We also discovered that the extant XSR chromosome has no effect on sex ratio or sterility in these backcross males. Whether shared QTL are caused by linkage or pleiotropy requires additional study. Nevertheless, these results indicate the presence of a “cryptic” drive system that is currently masked by suppressing elements that are associated with sterility and sperm length within but not between populations and, therefore, must have evolved since the populations became isolated, i.e., in hybrid sterility. PMID:25164880

Mating Frequency and Effects on Sex Ratio in Female Parasitoids of xanthopimpla Stemmator (Thunberg). Implications in biological control Programmes

International Nuclear Information System (INIS)

Gitau, C.W.

2002-01-01

Cereals, especially maize and sorghum are the most important field crops in Africa. classical biological Control is a management strategy that employs natural enemies against exotic pests on cereal crops. The method has been used against Chilo partellus (Swinhoe) (Lepidoptera: Crambidae), an introduced pest of maize, using the larval parasitoid cotesia flavipes (Cameron). However, C. flavipes is not able to attack all stem borer species in targeted areas. to complement its work, Xanthopimpla stemmator has successfully been established in Mauritius on Chilo sacchariphagus (Bojer). It is a common phenomenon for haplo-diploid parasitoids to give rise to male progeny when insemination does not take place. Mating becomes important to the parasitoid population since a male biased sex ratio can bring about collapse of the population. The aim of this study was to determine wether xanthopimpla stemmator females mat more than once and wether sex ratio of progeny is affected by multiple mating in female X. stemmator. The female showed a tendency to mate once. Multiple mating did not have any significant effect on either sex ratio or longevity. More males were produced in multiple mated females than once mated females.The effect of multiple mating in X. stemmator on sex ratio in relation to biocontrol programmes are discussed

Further observations on sex ratio among infants born to survivors of the atomic bombs, Hiroshima and Nagasaki

Energy Technology Data Exchange (ETDEWEB)

Schull, W J; Neel, J V; Hashizume, Asaji

1965-11-18

Data are presented on the sex ratio of 47,624 children born in Hiroshima and Nagasaki during 1956 to 1962. The total number of births in these two cities for which information is available is now 140,542, and of this number in 73,994 instances one or both parents were exposed to the atomic bombs. The suggestion of an effect of exposure on sex ratio in the earlier data is not borne out by the present findings. One can argue either that a small early effect has disappeared or that the original observation had no biological significance. 27 references, 4 tables.

African American adolescents meeting sex partners online: closing the digital research divide in STI/HIV prevention.

Science.gov (United States)

Whiteley, Laura B; Brown, Larry K; Swenson, Rebecca R; Valois, Robert F; Vanable, Peter A; Carey, Michael P; DiClemente, Ralph; Salazar, Laura F; Romer, Daniel

2012-02-01

Minority adolescents are affected disproportionately by HIV and STIs, and the Internet is a popular venue to meet sex partners. Little is known about the risks of this behavior for minority adolescents. The majority of studies that have examined sexual risk behavior online or STI/HIV prevention programs online have been among adult MSM. In this study, data from 1,045 African American youth found that 6% met sex partners online and in chat rooms. Odds ratios, adjusting for gender, found this behavior was associated with alcohol (AOR = 2.33, 95% CI [1.1, 4.7]) and drug use (AOR = 3.45, 95% CI [1.9, 6.1]), unprotected vaginal (AOR = 4.71, 95% CI [1.9, 8.4]) and anal sex (AOR = 4.77, 95% CI [1.3,17.1]) in the last 90 days, more lifetime vaginal (AOR = 3.65, 95% CI [2.0, 6.8]) and anal sex (AOR = 2.74, 95% CI [1.5, 4.8]), greater sexual sensation seeking (AOR = 2.92, 95% CI [1.5, 5.7]) and greater depression (AOR = 2.06, 95% CI [1.2, 3.6]. A final multiple logistic regression analyses found that male gender (AOR = 3.13, 95% CI [1.7, 5.8]), drug use at last sex (AOR = 2.41, 95% CI [1.3, 4.5]), lifetime history of vaginal (AOR = 2.90, 95% CI [1.5, 5.5]) and anal sex (AOR = 2.09, 95% CI [1.2, 3.6]), and cocaine use (AOR = 8.53, 95% CI [2.7, 27.3]) were independently associated with having sex with a partner met online. Meeting sex partners online is associated with a variety of risks among African American youth; however, the Internet may be an opportunity for intervention.

How Does Sex Trafficking Increase the Risk of HIV Infection? An Observational Study From Southern India

Science.gov (United States)

Wirth, Kathleen E.; Tchetgen Tchetgen, Eric J.; Silverman, Jay G.; Murray, Megan B.

2013-01-01

Studies have documented the substantial risk of human immunodeficiency virus (HIV) infection endured by sex-trafficked women, but it remains unclear how exposure to trafficking puts its victims at risk. We assessed whether the association between sex trafficking and HIV could be explained by self-reported forced prostitution or young age at entry into prostitution using cross-sectional data collected from 1,814 adult female sex workers in Karnataka, India, between August 2005 and August 2006. Marginal structural logistic regression was used to estimate adjusted odds ratios for HIV infection. Overall, 372 (21%) women met 1 or both criteria used to define sex trafficking: 278 (16%) began sex work before age 18 years, and 107 (5%) reported being forcibly prostituted. Thirteen (0.7%) met both criteria. Forcibly prostituted women were more likely to be HIV-infected than were women who joined the industry voluntarily, independent of age at entering prostitution (odds ratio = 2.30, 95% confidence interval: 1.08, 4.90). Conversely, after adjustment for forced prostitution and other confounders, no association between age at entry into prostitution and HIV was observed. The association between forced prostitution and HIV infection became stronger in the presence of sexual violence (odds ratio = 11.13, 95% confidence interval: 2.41, 51.40). These findings indicate that forced prostitution coupled with sexual violence probably explains the association between sex trafficking and HIV. PMID:23324332

Sex pheromone component ratios and mating isolation among three Lygus plant bug species of North America

Science.gov (United States)

Byers, John A.; Fefer, Daniela; Levi-Zada, Anat

2013-12-01

The plant bugs Lygus hesperus, Lygus lineolaris, and Lygus elisus (Hemiptera: Miridae) are major pests of many agricultural crops in North America. Previous studies suggested that females release a sex pheromone attractive to males. Other studies showed that males and females contain microgram amounts of ( E)-4-oxo-2-hexenal, hexyl butyrate, and ( E)-2-hexenyl butyrate that are emitted as a defense against predators. Using gas chromatography-mass spectrometry, we found that female L. lineolaris and L. elisus have a 4:10 ratio of hexyl butyrate to ( E)-2-hexenyl butyrate that is reversed from the 10:1 ratio in female L. hesperus (males of the three species have ~10:1 ratio). These reversed ratios among females of the species suggest a behavioral role. Because both sexes have nearly equal amounts of the major volatiles, females should release more to attract males. This expectation was supported because L. hesperus females released more hexyl butyrate (mean of 86 ng/h) during the night (1800-0700 hours) than did males (pheromone component for all three species, ( E)-2-hexenyl butyrate is essential for L. elisus and L. lineolaris, and hexyl butyrate is essential for L. hesperus. However, all three components are recognized by each species since ratios of the butyrate esters are critical for conspecific attraction and heterospecific avoidance by males and thus play a role in reproductive isolation among the three species. Because L. hesperus males and females are known to emit these major volatiles for repelling ant predators, our study links defensive allomones in Lygus bugs with an additional use as sex pheromones.

Sex differences in outcomes of primary prevention implantable cardioverter defibrillator therapy

DEFF Research Database (Denmark)

Sticherling, Christian; Arendacka, Barbora; Svendsen, Jesper Hastrup

2018-01-01

measures were overall mortality and first appropriate and first inappropriate shocks. A multivariable model enforcing a common hazard ratio for sex category across the centres, but allowing for centre-specific baseline hazards and centre specific effects of other covariates, was adjusted for age...

Prognostic utility of sestamibi lung uptake does not require adjustment for stress-related variables: A retrospective cohort study

International Nuclear Information System (INIS)

Leslie, William D; Yogendran, Marina S; Ward, Linda M; Nour, Khaled A; Metge, Colleen J

2006-01-01

Increased 99m Tc-sestamibi stress lung-to-heart ratio (sLHR) has been shown to predict cardiac outcomes similar to pulmonary uptake of thallium. Peak heart rate and use of pharmacologic stress affect the interpretation of lung thallium uptake. The current study was performed to determine whether 99m Tc-sestamibi sLHR measurements are affected by stress-related variables, and whether this in turn affects prognostic utility. sLHR was determined in 718 patients undergoing 99m Tc-sestamibi SPECT stress imaging. sLHR was assessed in relation to demographics, hemodynamic variables and outcomes (mean follow up 5.6 ± 1.1 years). Mean sLHR was slightly greater in males than in females (P < 0.01) and also showed a weak negative correlation with age (P < 0.01) and systolic blood pressure (P < 0.01), but was unrelated to stress method or heart rate at the time of injection. In patients undergoing treadmill exercise, sLHR was also positively correlated with peak workload (P < 0.05) but inversely with double product (P < 0.05). The combined explanatory effect of sex, age and hemodynamic variables on sLHR was less than 10%. The risk of acute myocardial infarction (AMI) or death increased by a factor of 1.7–1.8 for each SD increase in unadjusted sLHR, and was unaffected by adjustment for sex, age and hemodynamic variables (hazard ratios 1.6–1.7). The area under the ROC curve for the unadjusted sLHR was 0.65 (95% CI 0.59–0.71, P < 0.0001) and was unchanged for the adjusted sLHR (0.65, 95% CI 0.61–0.72, P < 0.0001). Stress-related variables have only a weak effect on measured sLHR. Unadjusted and adjusted sLHR provide equivalent prognostic information for prediction of AMI or death

Cognitive ability correlates positively with son birth and predicts cross-cultural variation of the offspring sex ratio

Science.gov (United States)

Dama, Madhukar Shivajirao

2013-06-01

Human populations show remarkable variation in the sex ratio at birth which is believed to be related to the parental condition. In the present study, the global variation of sex ratio at birth (SRB, proportion of male offspring born) was analyzed with respect to indirect measure of condition, the intelligence quotient (IQ). IQ correlates strongly with lifespan across nations, which makes it a good indicator of health of the large populations. Relation between three standard measures of average national IQ and SRB was studied using multiple linear regression models. Average national IQ was positively correlated with SRB ( r = 0.54 to 0.57, p difference in general condition of populations.

Temporal patterns in capture rate and sex ratio of forest bats in Arkansas

Science.gov (United States)

Roger W. Perry; S. Andrew Carter; Ronald E. Thill

2010-01-01

We quantified changes in capture rates and sex ratios from May to Sept. for eight species of bats, derived from 8 y of extensive mist netting in forests of the Ouachita Mountains, Arkansas. Our primary goal was to determine patterns of relative abundance for each species of bat captured over forest streams and to determine if these patterns were similar to patterns of...

Social and behavioural factors associated with condom use among direct sex workers in Siem Reap, Cambodia.

Science.gov (United States)

Wong, M L; Lubek, I; Dy, B C; Pen, S; Kros, S; Chhit, M

2003-04-01

To determine the social and behavioural factors associated with condom use among direct sex workers in Siem Reap, Cambodia. Using a structured behavioural questionnaire, interviews were conducted with 140 direct sex workers attending a health centre in Siem Reap for HIV screening. Consistent condom use with their clients was reported by 78% of sex workers compared to only 20% with their non-paying partners. Consistent condom use with clients was significantly higher among higher income than lower income sex workers (adjusted prevalence ratio: 1.91, 95% CI: 1.15 to 3.18) and those with good rather than poor negotiation skills (adjusted prevalence ratio: 1.51, 95% CI: 1.01 to 2.26), after adjustment for age, educational level, marital status, number of sexual encounters per week, and knowledge of AIDS/HIV and sexually transmitted infections. The most frequently reported reason for not using condoms with clients was not being able to persuade them (66.7%), while for non-paying partners, the reason was that they loved them (60.0%). To complement the government's current programme of client education, 100% condom policy and brothel administrative measures, additional strategies to increase condom use among clients and non-paying partners should be directed at (i) the social policy and community levels to address sex workers' economic and cultural barriers to condom use, and (ii) personal level empowerment through developing sex workers' condom negotiation skills.

Normal Female Germ Cell Differentiation Requires the Female X Chromosome to Autosome Ratio and Expression of Sex-Lethal in DROSOPHILA MELANOGASTER

OpenAIRE

Schüpbach, Trudi

1985-01-01

In somatic cells of Drosophila, the ratio of X chromosomes to autosomes (X:A ratio) determines sex and dosage compensation. The present paper addresses the question of whether germ cells also use the X:A ratio for sex determination and dosage compensation. Triploid female embryos were generated which, through the loss of an unstable ring-X chromosome, contained some germ cells of 2X;3A constitution in their ovaries. Such germ cells were shown to differentiate along one of two alternative pat...

An Adjusted Likelihood Ratio Approach Analysing Distribution of Food Products to Assist the Investigation of Foodborne Outbreaks

Science.gov (United States)

Norström, Madelaine; Kristoffersen, Anja Bråthen; Görlach, Franziska Sophie; Nygård, Karin; Hopp, Petter

2015-01-01

In order to facilitate foodborne outbreak investigations there is a need to improve the methods for identifying the food products that should be sampled for laboratory analysis. The aim of this study was to examine the applicability of a likelihood ratio approach previously developed on simulated data, to real outbreak data. We used human case and food product distribution data from the Norwegian enterohaemorrhagic Escherichia coli outbreak in 2006. The approach was adjusted to include time, space smoothing and to handle missing or misclassified information. The performance of the adjusted likelihood ratio approach on the data originating from the HUS outbreak and control data indicates that the adjusted approach is promising and indicates that the adjusted approach could be a useful tool to assist and facilitate the investigation of food borne outbreaks in the future if good traceability are available and implemented in the distribution chain. However, the approach needs to be further validated on other outbreak data and also including other food products than meat products in order to make a more general conclusion of the applicability of the developed approach. PMID:26237468

Biogas Improvement by Adding Australian Zeolite During the Anaerobic Digestion of C:N Ratio Adjusted Swine Manure

DEFF Research Database (Denmark)

Wijesinghe, D. Thushari N.; Dassanayake, Kithsiri B.; Sommer, Sven G.

2018-01-01

Abstract: Maintenance of the ideal carbon: nitrogen (C:N) ratio with a minimum level of TAN is a key challenge for achieving maximum potential CH4 production through the anaerobic digestion process of agricultural waste such as swine manure. Biogas production can be enhanced by adding zeolite...... into the anaerobic digestion medium. However, the effects of zeolite addition to C:N ratio adjusted feedstock, on the digester performance is unknown. The objectives of this study were to investigate the effect of Australian zeolite on anaerobic digestion of swine manure with a C:N ratio adjusted to 30...... and to determine the optimal zeolite application rate to achieve the best performance. The Australian zeolite significantly enhanced CH4 production and reduced the lag phase of anaerobic digestion in batch production. The optimal addition rate of zeolite was appeared to be around 40 g/L. The better digester...

Air pollution and respiratory hospital admissions in greater Paris: exploring sex differences.

Science.gov (United States)

Granados-Canal, D J; Chardon, B; Lefranc, A; Gremy, I

2005-01-01

The subject of sex and gender differences is relevant to the study of health effects of environmental exposures. In this study the authors aim at assessing the differences that may exist between males and females regarding short-term air pollution health effects. They studied the short-term relationships between air pollution levels and respiratory hospital admissions in greater Paris area for patients older than 15 years between 2000 and 2003. They also conducted time series analyses by using generalized additive models. For an increase of 10 microg/m3 in the air pollutant levels, the increase in relative risk of hospitalization was higher for males than for females and was significant only for males. These differences may not result solely from differences in biological susceptibility to air pollution because other factors related to gender (differences in individual exposures, in health care management, and so on) may play a role.

Gender and sex differences in job status and hypertension.

Science.gov (United States)

Clougherty, Jane E; Eisen, Ellen A; Slade, Martin D; Kawachi, Ichiro; Cullen, Mark R

2011-01-01

Studies have shown greater health risks associated with blue-collar manufacturing employment for women than men. It remains challenging, however, to distinguish gendered job status (affected by family composition and other personal characteristics) from sex-linked biological differences influencing physiological response to workplace physical hazards. We examined the effects of hourly (blue-collar) status on incident hypertension among men and women, using health claims data for 14, 618 white- and blue-collar aluminium manufacturing employees in eight US states. To explore gender differences in job status, we developed sex-stratified propensity score models identifying key socioeconomic predictors of hourly status for men and women. To examine the effects of hourly employment on hypertension risk, after adjusting for gender differences in job status, we applied time-weighted logistic regression models, stratified by propensity score, with additional adjustment for socioeconomic confounders. Family structure (partnership, parity) influenced job status for both sexes; single mothers were more likely to hold hourly jobs (OR 2.02; 95% CI 1.37 to 2.97) and partnered men with children less likely (OR 0.68; 95% CI 0.56 to 0.83). Education, age at hire and race influenced job status for both sexes. The effect of hourly status on hypertension was significant only among women predicted to be hourly (OR 1.78; 95% CI 1.34 to 2.35). Our results indicate significant risks of hypertension associated with hourly status for women, possibly exacerbated by sociodemographic factors predicting hourly status (eg, single parenthood, low education). Greater attention to gender differences in job status, and finer exploration of sex-linked biological differences influencing responsivity to workplace exposures, is warranted.

Conservation of Sex-Linked Markers among Conspecific Populations of a Viviparous Skink, Niveoscincus ocellatus, Exhibiting Genetic and Temperature-Dependent Sex Determination

Science.gov (United States)

Burridge, Christopher P; Ezaz, Tariq; Wapstra, Erik

2018-01-01

Abstract Sex determination systems are exceptionally diverse and have undergone multiple and independent evolutionary transitions among species, particularly reptiles. However, the mechanisms underlying these transitions have not been established. Here, we tested for differences in sex-linked markers in the only known reptile that is polymorphic for sex determination system, the spotted snow skink, Niveoscincus ocellatus, to quantify the genomic differences that have accompanied this transition. In a highland population, sex is determined genetically, whereas in a lowland population, offspring sex ratio is influenced by temperature. We found a similar number of sex-linked loci in each population, including shared loci, with genotypes consistent with male heterogamety (XY). However, population-specific linkage disequilibrium suggests greater differentiation of sex chromosomes in the highland population. Our results suggest that transitions between sex determination systems can be facilitated by subtle genetic differences. PMID:29659810

PCB concentrations and activity of sea lamprey Petromyzon marinus vary by sex

Science.gov (United States)

Madenjian, Charles P.; Johnson, Nicholas S.; Binder, Thomas R.; Rediske, Richard R.; O'Keefe, James P.

2013-01-01

We determined the polychlorinated biphenyl (PCB) concentrations of 40 male and 40 female adult sea lampreys Petromyzon marinus captured in the Cheboygan River, a tributary to Lake Huron, during May 2011. In addition, we performed a laboratory experiment using passive integrated transponder tags to determine whether male adult sea lampreys were more active than female adult sea lampreys. Sex had a significant effect on PCB concentration, and PCB concentration at a given level of sea lamprey condition was approximately 25 % greater in males than in females. Adjusting for the difference in condition between the sexes, males averaged a 17 % greater PCB concentration compared with females. Results from the laboratory experiment indicated that males were significantly more active than females. The observed sex difference in PCB concentrations was not due to female sea lampreys releasing eggs at spawning because the sea lamprey is semelparous, and we caught the sea lampreys before spawning. Rather, we attributed the sex difference in PCB concentrations to a greater rate of energy expenditure in males compared with females. We proposed that this greater rate of energy expenditure was likely due to greater activity. Our laboratory experiment results supported this hypothesis. A greater resting metabolic rate may also have contributed to a greater rate of energy expenditure. Our findings should eventually be applicable toward improving control of sea lamprey, a pest responsible for considerable damage to fisheries in lakes where it is not native.

The association between angiogenic markers and fetal sex

DEFF Research Database (Denmark)

Andersen, Louise Bjørkholt; Jørgensen, J S; Herse, F

2016-01-01

OBJECTIVE: Current research suggests sexual dimorphism between the male and female fetoplacental units, but with unknown relevance for preeclampsia. We investigated the association between fetal sex and concentrations of the angiogenic markers soluble Fms-like kinase 1 (sFlt-1), placental growth...... factor (PlGF), and sFlt-1/PlGF ratio in first and second-third trimester in women with/without preeclampsia, and the impact of fetal sex on the prognostic value of angiogenic markers for preeclampsia. STUDY DESIGN: Observational study in a prospective, population-based cohort of 2110 singleton...... (preeclampsia cases) associated with fetal sex in adjusted analyses (pfetal sex (all, p=0.028; preeclampsia, p=0.067) In receiver operating curve analysis, prediction of early-onset preeclampsia by sFlt-1/PlGF tended to be superior...

Maternal fructose and/or salt intake and reproductive outcome in the rat: effects on growth, fertility, sex ratio, and birth order.

Science.gov (United States)

Gray, Clint; Long, Sophie; Green, Charlotte; Gardiner, Sheila M; Craigon, Jim; Gardner, David S

2013-09-01

Maternal diet can significantly skew the secondary sex ratio away from the expected value of 0.5 (proportion males), but the details of how diet may do this are unclear. Here, we altered dietary levels of salt (4% salt in the feed) and/or fructose (10% in the drinking water) of pregnant rats to model potential effects that consumption of a "Western diet" might have on maternofetal growth, development, and sex ratio. We demonstrate that excess fructose consumption before and during pregnancy lead to a marked skew in the secondary sex ratio (proportion of males, 0.60; P < 0.006). The effect was not mediated by selective developmental arrest of female embryos or influenced by fetal position in the uterine horn or sex-specific effects on sperm motility, suggesting a direct effect of glycolyzable monosaccharide on the maternal ovary and/or ovulated oocyte. Furthermore, combined excess maternal consumption of salt and fructose-sweetened beverage significantly reduced fertility, reflected as a 50% reduction in preimplantation and term litter size. In addition, we also noted birth order effects in the rat, with sequential implantation sites tending to be occupied by the same sex.

Great tit hatchling sex ratios

NARCIS (Netherlands)

Lessells, C.M.; Mateman, A.C.; Visser, J.

1996-01-01

The sex of Great Tit Parus major nestlings was determined using PCR RAPDs. Because this technique requires minute amounts of DNA, chicks could be sampled soon (0-2d) after hatching, before any nestling mortality occurred. The proportion of males among 752 chicks hatching in 102 broods (98.9% of

Sex ratio variation in the bumblebee Bombus terrestris

DEFF Research Database (Denmark)

Duchateau, Marie José; Velthuis, Hayo H. W.; Boomsma, Jacobus Jan

2004-01-01

Bombus terrestris, bumblebees, colony development, queen control, reproductive strategies, sex allocation......Bombus terrestris, bumblebees, colony development, queen control, reproductive strategies, sex allocation...

National Differences in Trends for Heart Failure Hospitalizations by Sex and Race/Ethnicity.

Science.gov (United States)

Ziaeian, Boback; Kominski, Gerald F; Ong, Michael K; Mays, Vickie M; Brook, Robert H; Fonarow, Gregg C

2017-07-01

National heart failure (HF) hospitalization rates have not been appropriately age standardized by sex or race/ethnicity. Reporting hospital utilization trends by subgroup is important for monitoring population health and developing interventions to eliminate disparities. The National Inpatient Sample (NIS) was used to estimate the crude and age-standardized rates of HF hospitalization between 2002 and 2013 by sex and race/ethnicity. Direct standardization was used to age-standardize rates to the 2000 US standard population. Relative differences between subgroups were reported. The national age-adjusted HF hospitalization rate decreased 30.8% from 526.86 to 364.66 per 100 000 between 2002 and 2013. Although hospitalizations decreased for all subgroups, the ratio of the age-standardized rate for men compared with women increased from 20% greater to 39% ( P trend=0.002) between 2002 and 2013. Black men had a rate that was 229% ( P trend=0.141) and black women, 240% ( P trend=0.725) with reference to whites in 2013 with no significant change between 2002 and 2013. Hispanic men had a rate that was 32% greater in 2002 and the difference narrowed to 4% ( P trend=0.047) greater in 2013 relative to whites. For Hispanic women, the rate was 55% greater in 2002 and narrowed to 8% greater ( P trend=0.004) in 2013 relative to whites. Asian/Pacific Islander men had a 27% lower rate in 2002 that improved to 43% ( P trend=0.040) lower in 2013 relative to whites. For Asian/Pacific Islander women, the hospitalization rate was 24% lower in 2002 and improved to 43% ( P trend=0.021) lower in 2013 relative to whites. National HF hospitalization rates have decreased steadily during the recent decade. Disparities in HF burden and hospital utilization by sex and race/ethnicity persist. Significant population health interventions are needed to reduce the HF hospitalization burden among blacks. An evaluation of factors explaining the improvements in the HF hospitalization rates among

Influence of gender preference and sex composition of surviving ...

African Journals Online (AJOL)

Women who have GP and same LCSC were 1.35 and 2.4 times significantly more likely to have intention to bear more children than those who have no GP and different sexes composition respectively. These odd ratios changed to 1.38 for GP and 2.44 for LCSC after adjusting for other socio-demographic variables.

Effect of Temperature on Reproduction and Sex Ratio of Guppy (Poecilia reticulata Peters

Directory of Open Access Journals (Sweden)

H. Arfah

2007-01-01

Full Text Available Water temperature could affect the reproduction of broodstock and sex ratio of progeny.  In this study, broodstock of guppy (Poecilia reticulata Peters was reared in different temperature to determine its effect on reproduction of broodstock and sex ratio of their progeny. The result of study show that broodstock reared at 27°C produced more fry (16 males mean than that of 30°C (10 males, while broodstock reared at 33°C produced no progeny.  Percentage of male fish produced by broodstock reared at 30°C is higher than that of 27°C.  Incubation time of embryo before birth is sorter in broodstock reared at 30°C (4-12 days compared with 27°C (18-22 days.  However, several progeny of broodstock reared at 30°C had abnormal vertebrae. Keywords: guppy, Poecilia reticulata, sex reversal, reproduction, monosex   ABSTRAK Suhu air inkubasi diduga dapat mempengaruhi reproduksi induk ikan dan nisbah kelamin keturunannya.  Pada penelitian ini, induk ikan gapi (Poecilia reticulata Peters dipelihara pada suhu 27°C, 30°C dan suhu 33°C untuk mengetahui pengaruhnya terhadap reproduksi dan rasio kelamin keturunannya.  Hasil penelitian menunjukkan bahwa induk ikan gapi yang dipelihara pada suhu 27°C menghasilkan anak lebih banyak (rata-rata 16 ekor daripada di suhu 30°C (10 ekor, sementara induk gagal melahirkan pada suhu pemeliharaan 33°C. Proporsi anak jantan yang dihasilkan oleh induk yang dipelihara pada suhu 30°C lebih banyak dibandingkan pada suhu 27°C.  Waktu inkubasi embrio sebelum dilahirkan oleh induk yang dipelihara pada suhu 30°C lebih singkat, yaitu 4-12 hari, dibandingkan pada  suhu 27°C, 18-22 hari.  Namun demikian beberapa anak ikan yang lahir dari induk yang dipelihara pada suhu suhu 30°C mengalami abnormalitas pada bagian tulang belakangnya.  Kata kunci: ikan gapi, Poecilia reticulata, sex reversal, reproduksi, monoseks

Arterial stiffness and wave reflection: sex differences and relationship with left ventricular diastolic function.

Science.gov (United States)

Russo, Cesare; Jin, Zhezhen; Palmieri, Vittorio; Homma, Shunichi; Rundek, Tatjana; Elkind, Mitchell S V; Sacco, Ralph L; Di Tullio, Marco R

2012-08-01

Increased arterial stiffness and wave reflection have been reported in heart failure with normal ejection fraction (HFNEF) and in asymptomatic left ventricular (LV) diastolic dysfunction, a precursor of HFNEF. It is unclear whether women, who have higher frequency of HFNEF, are more vulnerable than men to the deleterious effects of arterial stiffness on LV diastolic function. We investigated, in a large community-based cohort, whether sex differences exist in the relationship among arterial stiffness, wave reflection, and LV diastolic function. Arterial stiffness and wave reflection were assessed in 983 participants from the Cardiovascular Abnormalities and Brain Lesions study using applanation tonometry. The central pulse pressure/stroke volume index, total arterial compliance, pulse pressure amplification, and augmentation index were used as parameters of arterial stiffness and wave reflection. LV diastolic function was evaluated by 2-dimensional echocardiography and tissue-Doppler imaging. Arterial stiffness and wave reflection were greater in women compared with men, independent of body size and heart rate (all Pfunction in both sexes. Further adjustment for cardiovascular risk factors attenuated these relationships; however, a higher central pulse pressure/stroke volume index predicted LV diastolic dysfunction in women (odds ratio, 1.54; 95% confidence intervals, 1.03 to 2.30) and men (odds ratio, 2.09; 95% confidence interval, 1.30 to 3.39), independent of other risk factors. In conclusion, in our community-based cohort study, higher arterial stiffness was associated with worse LV diastolic function in men and women. Women's higher arterial stiffness, independent of body size, may contribute to their greater susceptibility to develop HFNEF.

Delimitation of the embryonic thermosensitive period for sex determination using an embryo growth model reveals a potential bias for sex ratio prediction in turtles.

Science.gov (United States)

Girondot, Marc; Monsinjon, Jonathan; Guillon, Jean-Michel

2018-04-01

The sexual phenotype of the gonad is dependent on incubation temperature in many turtles, all crocodilians, and some lepidosaurians. At hatching, identification of sexual phenotype is impossible without sacrificing the neonates. For this reason, a general method to infer sexual phenotype from incubation temperatures is needed. Temperature influences sex determination during a specific period of the embryonic development, starting when the gonad begins to form. At constant incubation temperatures, this thermosensitive period for sex determination (TSP) is located at the middle third of incubation duration (MTID). When temperature fluctuates, the position of the thermosensitive period for sex determination can be shifted from the MTID because embryo growth is affected by temperature. A method is proposed to locate the thermosensitive period for sex determination based on modelling the embryo growth, allowing its precise identification from a natural regime of temperatures. Results from natural nests and simulations show that the approximation of the thermosensitive period for sex determination to the middle third of incubation duration may create a quasi-systematic bias to lower temperatures when computing the average incubation temperature during this period and thus a male-bias for sex ratio estimate. Copyright © 2018 Elsevier Ltd. All rights reserved.

Testosterone has a long-term effect on primary sex ratio of first eggs in pigeons-in search of a mechanism

NARCIS (Netherlands)

Goerlich, V. C.; Dijkstra, C.; Schaafsma, S. M.; Groothuis, T. G. G.

2009-01-01

Despite accumulating evidence that birds, in which females are the heterogametic sex, are able to manipulate primary offspring sex ratio, the underlying mechanism remains elusive. Steroid hormones. which govern female reproduction and are also accumulated by the developing follicle could potentially

Selective interactions among Rh, ABO, and sex ratio of newborns.

Science.gov (United States)

Valenzuela, C Y; Walton, R

1985-01-01

The hypothesis that the Rh and ABO blood systems behave like the HLA system in relation to mother-conception tolerance-rejection mechanisms was tested in 25,501 mother-infant pairs. According to this hypothesis, heterozygotes carrying a paternal gene that is not present in their mothers should be better tolerated than homozygotes. Significantly more BO infants born to AO mothers. AO infants born to BO mothers, Rh(+) heterozygotes born to Rh(-) mothers, and less significantly AO infants born to OO mothers confirm the hypothesis. Fewer homozygotes occurred in Rh(-) infants born to Rh(+) mothers and in O infants born to non-O mothers. Deviations from the Hardy-Weinberg equilibrium found in the ABO system were modified by the Rh and sex of the infant. These data strongly support the hypothesis that at least two feto-maternal systems influence the destiny of pregnancies: the classical known incompatibility system which operates late in pregnancy and a new one which is based on the induction of maternal tolerance early in pregnancy: maternal tolerance seems to be better elicited by heterozygous eggs or embryos carrying a gene not present in the mother. The data also support the hypothesis that the sex ratio is influenced by feto-maternal tolerance-rejection mechanisms associated with the ABO and Rh systems.

Sex allocation in fungus-growing ants: worker or queen control without symbiont-induced female bias

DEFF Research Database (Denmark)

Dijkstra, Michiel B.; Boomsma, Jacobus Jan

2008-01-01

The fungal cultivars of fungus-growing ants are vertically transmitted by queens but not males. Selection would therefore favor cultivars that bias the ants' sex ratio towards gynes, beyond the gyne bias that is optimal for workers and queens. We measured sex allocation in 190 colonies of six...... sympatric fungus-growing ant species. As predicted from relatedness, female bias was greater in four singly mated Sericomyrmex and Trachymyrmex species than in two multiply mated Acromyrmex species. Colonies tended to raise mainly a single sex, which could be partly explained by variation in queen number......, colony fecundity, and fungal garden volume for Acromyrmex and Sericomyrmex, but not for Trachymyrmex. Year of collection, worker number and mating frequency of Acromyrmex queens did not affect the colony sex ratios. We used a novel sensitivity analysis to compare the population sex allocation ratios...

Seasonal variation in Eurasian Wigeon Anas penelope sex and age ratios from hunter-based surveys

DEFF Research Database (Denmark)

Clausen, Kevin Kuhlmann; Dalby, Lars; Sunde, Peter

2013-01-01

dominated by adult males, and juvenile proportions were highest in November and significantly lower before and after this peak. Nationwide field assessments undertaken in January 2012 showed no significant differences from sex and age ratios in the wing survey data from that particular hunting season (2011...... schemes. This study found consistent seasonal variation in Eurasian Wigeon Anas penelope sex and age ratios among Danish hunter-based wing surveys, and describes how accounting for this variation might explain reported discrepancies between this and other monitoring methods. Early season flocks were....../2012), indicating that this survey is a good predictor of Wigeon demography. These results highlight the need to account for consistent temporal variation in such demographic time series when using the results to model population parameters....

Mapping Causes and Implications of India's Skewed Sex Ratio and Poverty problem using Fuzzy & Neutrosophic Relational Maps

OpenAIRE

Gaurav; Kumar, Megha; Bhutani, Kanika; Aggarwal, Swati

2016-01-01

Numerous studies by different researchers have confirmed that skewed sex ratio is a critical social problem in India. This enduring problem of gender imbalance is the collective result of factors like sex selective abortion, gender discrimination, son preference for the preservation of tribe, emergence of new technologies in medical field and many more factors. Another severe problem to be addressed in India is poverty. Many factors contribute to the perpetuation of poverty such as illiteracy...

The evolution of sex roles in birds is related to adult sex ratio

OpenAIRE

Liker, András; Freckleton, Robert P.; Székely, Tamás

2013-01-01

Sex-role reversal represents a formidable challenge for evolutionary biologists, since it is not clear which ecological, life-history or social factors facilitated conventional sex roles (female care and male-male competition for mates) to be reversed (male care and female-female competition). Classic theories suggested ecological or life-history predictors of role reversal, but most studies failed to support these hypotheses. Recent theory however predicts that sex-role reversal should be dr...

Sex work, injection drug use, and abscesses: Associations in women, but not men.

Science.gov (United States)

Wurcel, Alysse G; Burke, Deirdre; Skeer, Margie; Landy, David; Heimer, Robert; Wong, John B; Chui, Kenneth K H; Stopka, Thomas J

2018-04-01

Abscesses commonly occur among people who inject drugs (PWID). However, whether the risks are comparable between males and females, and the impact of sex work on abscess risk is unclear. The goal of this study was to examine the contemporary associations of gender and sex work with the risk of abscesses in PWID. Combining data from two cross-sectional studies conducted in the Greater Boston Area with people at risk for HIV and hepatitis C virus (HCV), we used the following inclusion criteria: age 18-45 years and report of illicit or non-prescription drug injection within the 30 days prior to the survey. Information on demographics, injection-mediated risks, and sexual behaviors was collected using Audio Computer-Assisted Self-Interview Software. Multivariable logistic regressions were used to model associations. The study sample included 298 people including 30% were female. Females were more likely than men to report sex work (28% vs. 16%, p = .012) and abscess during their lifetime (55% vs. 37% p = .004). Among the females, engaging in sex work increased by >5-fold the odds of reporting abscesses [Adjusted odds ratio 5.42; 95% CI: 1.27, 23.10]. There was no association between sex work and abscesses among men. We found a female-specific association between sex work, injection drug use, and abscesses among PWID. Although the cross-sectional designs precluded causal inferences, longitudinal studies could enhance understanding of gender-associated risks for abscesses and inform the development of harm reduction interventions. Published by Elsevier B.V.

Considering sex and gender in Alzheimer disease and other dementias.

Science.gov (United States)

Podcasy, Jessica L; Epperson, C Neill

2016-12-01

Suffering related to dementia is multifaceted because cognitive and physical functioning slowly deteriorates. Advanced age and sex, two of the most prominent risk factors for dementia, are not modifiable. Lifestyle factors such as smoking, excessive alcohol use, and poor diet modulate susceptibility to dementia in both males and females. The degree to which the resulting health conditions (eg, obesity, type 2 diabetes, and cardiovascular disease) impact dementia risk varies by sex. Depending on the subtype of dementia, the ratio of male to female prevalence differs. For example, females are at greater risk of developing Alzheimer disease dementia, whereas males are at greater risk of developing vascular dementia. This review examines sex and gender differences in the development of dementia with the goal of highlighting factors that require further investigation. Considering sex as a biological variable in dementia research promises to advance our understanding of the pathophysiology and treatment of these conditions.

'Female condoms give women greater control': a qualitative assessment of the experiences of commercial sex workers in Swaziland.

Science.gov (United States)

Mathenjwa, Thulile; Maharaj, Pranitha

2012-10-01

To explore commercial sex workers' experiences with the female condom in Swaziland. This is a qualitative study that draws on two focus group discussions and ten individual in-depth interviews with female commercial sex workers in Lavumisa, Swaziland. The findings suggest that the majority of female sex workers prefer to use the female condom with their clients because it offers them greater control over the sexual encounter. Other factors that facilitate its use include the absence of side effects, the enhancement of sexual pleasure and protection against the risk of STIs (including HIV). In addition, the women reported that the female condom is stronger and more resistant to breakage than the male condom. Moreover, the female condoms can be inserted well in advance of sexual intercourse. Difficulties of insertion, partner objection and limited product availability were some of the barriers to the use of the device. There was also a tendency to reuse the female condoms because of lack of product availability and privacy to insert it. Although female condom use involves negotiation with clients, the fact that it offers sex workers an independent method of protection gives them more power and also, increases their ability to control their sexual and reproductive health.

Genome-wide association study uncovers a novel QTL allele of AtS40-3 that affects the sex ratio of cyst nematodes in Arabidopsis.

Science.gov (United States)

Anwer, Muhammad Arslan; Anjam, Muhammad Shahzad; Shah, Syed Jehangir; Hasan, M Shamim; Naz, Ali A; Grundler, Florian M W; Siddique, Shahid

2018-03-24

Plant-parasitic cyst nematodes are obligate sedentary parasites that infect the roots of a broad range of host plants. Cyst nematodes are sexually dimorphic, but differentiation into male or female is strongly influenced by interactions with the host environment. Female populations typically predominate under favorable conditions, whereas male populations predominate under adverse conditions. Here, we performed a genome-wide association study (GWAS) in an Arabidopsis diversity panel to identify host loci underlying variation in susceptibility to cyst nematode infection. Three different susceptibility parameters were examined, with the aim of providing insights into the infection process, the number of females and males present in the infected plant, and the female-to-male sex ratio. GWAS results suggested that variation in sex ratio is associated with a novel quantitative trait locus allele on chromosome 4. Subsequent candidate genes and functional analyses revealed that a senescence-associated transcription factor, AtS40-3, and PPR may act in combination to influence nematode sex ratio. A detailed molecular characterization revealed that variation in nematode sex ratio was due to the disturbed common promoter of AtS40-3 and PPR genes. Additionally, single nucleotide polymorphisms in the coding sequence of AtS40-3 might contribute to the natural variation in nematode sex ratio.

Sex ratio of the offspring of Sprague-Dawley rats exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in utero and lactationally in a three-generation study

International Nuclear Information System (INIS)

Rowlands, J.C.; Budinsky, R.A.; Aylward, L.L.; Faqi, A.S.; Carney, E.W.

2006-01-01

Reports of a decreased male/female sex ratio in children born to males exposed to TCDD in Seveso, Italy, at a young age have sparked examinations of this endpoint in other populations exposed to TCDD or related compounds. Overall, the male/female sex ratio results reported in these studies, with slightly different age-exposed male populations, have shown mixed results. Experimental studies of the effects of in utero exposure to TCDD in laboratory animals have reported no effect on the f 1 sex ratio and mixed results for the sex ratio of the f 2 generation. In order to better understand the potential effects of TCDD on second generation sex ratio, we retrieved archived data from a comprehensive three-generation feeding study of TCDD in rats that was conducted and published in the 1970s, but which did not publish data on sex ratio of the offspring [Murray, F.J., Smith, F.A., Nitschke, K.D., Humiston, C.G., Kociba, R.J., Schwetz, B.A., 1979. Three-generation reproduction study of rats given 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the diet. Toxicol. Appl. Pharmacol. 50, 241-252]. A re-examination of the original Murray et al. data found no statistically significant treatment-related changes in postnatal day 1 sex ratio in any generation of treated animals, consistent with one other relatively large study reporting on this endpoint. We discuss mechanistic data underlying a potential effect of TCDD on this endpoint. We conclude that the inconsistency in findings on sex ratio of the offspring of male rats exposed to TCDD in utero is likely due to random variation associated with a relatively small sample size, although differences between studies in strain of rat, dose regimen, and day of ascertainment of sex ratio cannot be ruled out

Optimization of Sex Ratio in a Selection Plan for Palas Prolificacy Line

Directory of Open Access Journals (Sweden)

Răzvan Popa

2011-05-01

Full Text Available The aim of the paper work is to optimize the sex ratio in a selection plan, according to model developed by King (1961, which will be proposed to be applied for prolificacy improvement in Prolific Line Palas. The method used in this paper work is modeling, which exist in the most animal breeding scientifically papers. After the simulations, we observed that the most convenient variant was that which prefigure use of 13 rams on reproduction activity. This variant offer a genetic gain per generation by 0.47497 additive standard deviations.

Crop Condition Assessment with Adjusted NDVI Using the Uncropped Arable Land Ratio

Directory of Open Access Journals (Sweden)

Miao Zhang

2014-06-01

Full Text Available Crop condition assessment in the early growing stage is essential for crop monitoring and crop yield prediction. A normalized difference vegetation index (NDVI-based method is employed to evaluate crop condition by inter-annual comparisons of both spatial variability (using NDVI images and seasonal dynamics (based on crop condition profiles. Since this type of method will generate false information if there are changes in crop rotation, cropping area or crop phenology, information on cropped/uncropped arable land is integrated to improve the accuracy of crop condition monitoring. The study proposes a new method to retrieve adjusted NDVI for cropped arable land during the growing season of winter crops by integrating 16-day composite Moderate Resolution Imaging Spectroradiometer (MODIS reflectance data at 250-m resolution with a cropped and uncropped arable land map derived from the multi-temporal China Environmental Satellite (Huan Jing Satellite charge-coupled device (HJ-1 CCD images at 30-m resolution. Using the land map’s data on cropped and uncropped arable land, a pixel-based uncropped arable land ratio (UALR at 250-m resolution was generated. Next, the UALR-adjusted NDVI was produced by assuming that the MODIS reflectance value for each pixel is a linear mixed signal composed of the proportional reflectance of cropped and uncropped arable land. When UALR-adjusted NDVI data are used for crop condition assessment, results are expected to be more accurate, because: (i pixels with only uncropped arable land are not included in the assessment; and (ii the adjusted NDVI corrects for interannual variation in cropping area. On the provincial level, crop growing profiles based on the two kinds of NDVI data illustrate the difference between the regular and the adjusted NDVI, with the difference depending on the total area of uncropped arable land in the region. The results suggested that the proposed method can be used to improve the assessment of

Colony size, sex ratio and cohabitation in roosts of Phyllostomus hastatus (Pallas (Chiroptera: Phyllostomidae

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LM. Costa

Full Text Available Phyllostomus hastatus bat is species broadly distributed over the Neotropical region, which uses as diurnal roosts caves, hollow trees, palm leaves and human buildings. Thirteen diurnal roosts of P. hastatus were analysed from 1990 to 2009 in several localities of Rio de Janeiro State, regarding environment (rural, urban or protected area, type of roost (hollow tree, basement or roof, sex ratio and cohabitation. A nocturnal roost was also analysed. Sex ratio of P. hastatus varied considerably among roosts what may be explained by the fact this species can roost alone, in couples, in harems or in groups of bachelor males. Phyllostomus hastatus was observed in cohabitation with three other species: Molossus rufus, Molossus molossus and Myotis nigricans. Due to the frequency of cohabitation observed between P. hastatus and species of the genus Molossus, one or more advantages for the members of this association may be expected. The simultaneous usage of a feeding roost by a group of bachelor males is unknown information in the literature, and may suggest that this kind of group may interact with each other even when away from their diurnal roosts.

Positive selection of deleterious alleles through interaction with a sex-ratio suppressor gene in African Buffalo: a plausible new mechanism for a high frequency anomaly.

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Pim van Hooft

Full Text Available Although generally rare, deleterious alleles can become common through genetic drift, hitchhiking or reductions in selective constraints. Here we present a possible new mechanism that explains the attainment of high frequencies of deleterious alleles in the African buffalo (Syncerus caffer population of Kruger National Park, through positive selection of these alleles that is ultimately driven by a sex-ratio suppressor. We have previously shown that one in four Kruger buffalo has a Y-chromosome profile that, despite being associated with low body condition, appears to impart a relative reproductive advantage, and which is stably maintained through a sex-ratio suppressor. Apparently, this sex-ratio suppressor prevents fertility reduction that generally accompanies sex-ratio distortion. We hypothesize that this body-condition-associated reproductive advantage increases the fitness of alleles that negatively affect male body condition, causing genome-wide positive selection of these alleles. To investigate this we genotyped 459 buffalo using 17 autosomal microsatellites. By correlating heterozygosity with body condition (heterozygosity-fitness correlations, we found that most microsatellites were associated with one of two gene types: one with elevated frequencies of deleterious alleles that have a negative effect on body condition, irrespective of sex; the other with elevated frequencies of sexually antagonistic alleles that are negative for male body condition but positive for female body condition. Positive selection and a direct association with a Y-chromosomal sex-ratio suppressor are indicated, respectively, by allele clines and by relatively high numbers of homozygous deleterious alleles among sex-ratio suppressor carriers. This study, which employs novel statistical techniques to analyse heterozygosity-fitness correlations, is the first to demonstrate the abundance of sexually-antagonistic genes in a natural mammal population. It also has

Sex ratio of offspring and occupational exposure to fly ash : a historical cohort study of municipal solid waste incinerator workers in Japan

Energy Technology Data Exchange (ETDEWEB)

Mori, I.; Ogawa, Y. [National Inst. of Industrial Health, Tokyo (Japan); Kumagai, S. [Osaka Prefectural Inst. of Public Health, Osaka (Japan); Koda, S. [Kochi Medical School, Nangoku (Japan); Ueno, M. [All-Japan Prefectural and Municipal Workers Union, Tokyo (Japan)

2005-07-01

This paper described a cohort study which focused on risk assessment for cancer mortality and changes in the sex ratio of offspring among municipal solid waste incinerator (MSWI) workers in Japan. A baseline survey was conducted by survey with both MSWI workers as well as a reference population of waste collection workers. Questions were related to offspring, job history, and frequency of exposure to fly ash during incinerator work. A total of 5211 records were then analyzed as well as 10,571 children. Duration of exposure to fly ash was used as a surrogate exposure index. Results showed that longer exposure to fly ash influenced the sex ratio. Results of a multivariate analysis conducted to compute the odds ratio of female birth by different exposure indices were similar to results obtained in a univariate analysis. It was concluded that an association between duration of exposure to fly ash and changes in sex ratio was determined. 5 refs., 3 tabs.

Germ-line origins of mutation in families with hemophilia B: The sex ratio varies with the type of mutation

Energy Technology Data Exchange (ETDEWEB)

Ketterling, R.P.; Vielhaber, E.; Bottema, C.D.K.; Schaid, D.J.; Sommer, S.S. (Mayo Clinic/Foundation, Rochester, MN (United States)); Cohen, M.P. (Vanderbilt Univ., Nashville, TN (United States)); Sexauer, C.L. (Children' s Hospital, Oklahoma City, OK (United States))

1993-01-01

Previous epidemiological and biochemical studies have generated conflicting estimates of the sex ratio of mutation. Direct genomic sequencing in combination with haplotype analysis extends previous analyses by allowing the precise mutation to be determined in a given family. From analysis of the factor IX gene of 260 consecutive families with hemophilia B, the authors report the germ-line origin of mutation in 25 families. When combined with 14 origins of mutation reported by others and with 4 origins previously reported by them, a total of 25 occur in the female germ line, and 18 occur in the male germ line. The excess of germ-line origins in females does not imply an overall excess mutation rate per base pair in the female germ line. Bayesian analysis of the data indicates that the sex ratio varies with the type of mutation. The aggregate of single-base substitutions shows a male predominance of germ-line mutations (P < .002). The maximum-likelihood estimate of the male predominance is 3.5-fold. Of the single-base substitutions, deletions display a sex ratio of unity. Analysis of the parental age at transmission of a new mutation suggests that germ-line mutations are associated with a small increase in parental age in females but little, if any, increase in males. Although direct genomic sequencing offers a general method for defining the origin of mutation in specific families, accurate estimates of the sex ratios of different mutational classes require large sample sizes and careful correction for multiple biases of ascertainment. The biases in the present data result in an underestimate of the enhancement of mutation in males. 62 refs., 1 fig., 5 tabs.

Considering sex and gender in Alzheimer disease and other dementias

Science.gov (United States)

Podcasy, Jessica L.; Epperson, C. Neill

2016-01-01

Suffering related to dementia is multifaceted because cognitive and physical functioning slowly deteriorates. Advanced age and sex, two of the most prominent risk factors for dementia, are not modifiable. Lifestyle factors such as smoking, excessive alcohol use, and poor diet modulate susceptibility to dementia in both males and females. The degree to which the resulting health conditions (eg, obesity, type 2 diabetes, and cardiovascular disease) impact dementia risk varies by sex. Depending on the subtype of dementia, the ratio of male to female prevalence differs. For example, females are at greater risk of developing Alzheimer disease dementia, whereas males are at greater risk of developing vascular dementia. This review examines sex and gender differences in the development of dementia with the goal of highlighting factors that require further investigation. Considering sex as a biological variable in dementia research promises to advance our understanding of the pathophysiology and treatment of these conditions. PMID:28179815

Influence of Propylparaben on Vitellogenesis and Sex Ratio in Juvenile Zebrafish (Danio rerio

Directory of Open Access Journals (Sweden)

Přemysl Mikula

2009-01-01

Full Text Available The aim of the study was to evaluate the xeno-oestrogenic potential of propylparaben in vivo using zebrafish (Danio rerio. Experimental juvenile zebrafish (20 days post hatching were fed a feed containing 500, 1000, or 2000 mg kg-1 of propylparaben, fish in a positive control group were given a feed treated with 20 mg kg-1 of 17β-oestradiol, and the control fish were given the feed free of either tested substance. The exposure of fish to propylparaben did not affect vitellogenesis after 20 days exposure but seemed to influence the sex differentiation processes, as evidenced by a sex ratio significantly skewed towards females in the group fed 500 mg kg-1 of propylparaben following 45 days of exposure. The potential of the fish to respond to oestrogenic stimulation was confirmed, since significantly higher vitellogenin concentrations were detected in the fish from the positive control group.

Juvenile exposure to vinclozolin shifts sex ratios and impairs reproductive capacity of zebrafish.

Science.gov (United States)

Lor, Yer; Revak, Andrew; Weigand, Jenna; Hicks, Elisabeth; Howard, David R; King-Heiden, Tisha C

2015-12-01

Exposure to endocrine disruptors during critical periods of development can impact the sustainability of wild fish populations. Anti-androgenic compounds have received less attention, but are capable of modulating gonad differentiation and maturation, and impairing reproduction in fish. The fungicide vinclozolin (VZ) has been shown to impair reproduction in adult fish, but less is known about its effects following exposure earlier in development. Here we show that waterborne exposure to 400μg VZ/L during critical periods of sex differentiation (21-35 days post fertilization) permanently shifts sex ratios towards females, and alters the maturation of the gonad. Both fecundity and fertility were reduced, even when oogenesis and spermatogenesis recover and sperm motility is not altered. These results demonstrate the need to better understand the impacts of early exposure to anti-androgenic compounds on fish. Copyright © 2015 Elsevier Inc. All rights reserved.

Individual, Psychosocial, and Social Correlates of Unprotected Anal Intercourse in a New Generation of Young Men Who Have Sex With Men in New York City

Science.gov (United States)

Kapadia, Farzana; Siconolfi, Daniel E.; Moeller, Robert W.; Figueroa, Rafael Perez; Barton, Staci C.; Blachman-Forshay, Jaclyn

2013-01-01

Objectives. We examined associations of individual, psychosocial, and social factors with unprotected anal intercourse (UAI) among young men who have sex with men in New York City. Methods. Using baseline assessment data from 592 young men who have sex with men participating in an ongoing prospective cohort study, we conducted multivariable logistic regression analyses to examine the associations between covariates and likelihood of recently engaging in UAI with same-sex partners. Results. Nineteen percent reported recent UAI with a same-sex partner. In multivariable models, being in a current relationship with another man (adjusted odds ratio [AOR] = 4.87), an arrest history (AOR = 2.01), greater residential instability (AOR = 1.75), and unstable housing or homelessness (AOR = 3.10) was associated with recent UAI. Although high levels of gay community affinity and low internalized homophobia were associated with engaging in UAI in bivariate analyses, these associations did not persist in multivariable analyses. Conclusions. Associations of psychosocial and socially produced conditions with UAI among a new generation of young men who have sex with men warrant that HIV prevention programs and policies address structural factors that predispose sexual risk behaviors. PMID:23488487

Factorial Invariance of the Scale Beliefs about Children's Adjustment in Same-Sex Families in Spanish, Chilean, and Hispanic University Students

Science.gov (United States)

Pascual-Soler, Marcos; Frias-Navarro, Dolores; Barrientos-Delgado, Jaime; Badenes-Ribera, Laura; Monterde-i-Bort, Hector; Cárdenas-Castro, Manuel; Berrios-Riquelme, José

2017-01-01

This study examines the factorial invariance of the Scale on Beliefs About Children's Adjustment in Same-Sex Families (SBCASSF) across countries in three samples: Chilean, Spanish, and Hispanic university students. The scale analyzes attitudes toward the consequences of the rearing and education of children by parents with a homosexual sexual…

Sex and death: the effects of innate immune factors on the sexual reproduction of malaria parasites.

Directory of Open Access Journals (Sweden)

Ricardo S Ramiro

2011-03-01

Full Text Available Malaria parasites must undergo a round of sexual reproduction in the blood meal of a mosquito vector to be transmitted between hosts. Developing a transmission-blocking intervention to prevent parasites from mating is a major goal of biomedicine, but its effectiveness could be compromised if parasites can compensate by simply adjusting their sex allocation strategies. Recently, the application of evolutionary theory for sex allocation has been supported by experiments demonstrating that malaria parasites adjust their sex ratios in response to infection genetic diversity, precisely as predicted. Theory also predicts that parasites should adjust sex allocation in response to host immunity. Whilst data are supportive, the assumptions underlying this prediction - that host immune responses have differential effects on the mating ability of males and females - have not yet been tested. Here, we combine experimental work with theoretical models in order to investigate whether the development and fertility of male and female parasites is affected by innate immune factors and develop new theory to predict how parasites' sex allocation strategies should evolve in response to the observed effects. Specifically, we demonstrate that reactive nitrogen species impair gametogenesis of males only, but reduce the fertility of both male and female gametes. In contrast, tumour necrosis factor-α does not influence gametogenesis in either sex but impairs zygote development. Therefore, our experiments demonstrate that immune factors have complex effects on each sex, ranging from reducing the ability of gametocytes to develop into gametes, to affecting the viability of offspring. We incorporate these results into theory to predict how the evolutionary trajectories of parasite sex ratio strategies are shaped by sex differences in gamete production, fertility and offspring development. We show that medical interventions targeting offspring development are more likely

Changes in the sex ratio of the Common Pochard Aythya ferina in Europe and North Africa

NARCIS (Netherlands)

Brides, Kane; Wood, Kevin; Hearn, Richard; Fijen, T.P.M.

2017-01-01

Assessments of the sex ratio among Common Pochard Aythya ferina flocks were undertaken in countries across Europe and into North Africa in January 2016, for comparison with results from surveys carried out over the same area in January 1989 and January 1990. The mean (± 95% CI) proportions of males

The influence of sex and obesity on gait biomechanics in people with severe knee osteoarthritis scheduled for arthroplasty.

Science.gov (United States)

Paterson, K L; Sosdian, L; Hinman, R S; Wrigley, T V; Kasza, J; Dowsey, M; Choong, P; Bennell, K L

2017-11-01

Sex and body mass may influence knee biomechanics associated with poor total knee arthroplasty (TKA) outcomes for knee osteoarthritis (OA). This study aimed to determine if gait differed between men and women, and overweight and class I obese patients with severe knee OA awaiting TKA. 34 patients with severe knee OA (average age 70.0 (SD 7.2) years, body mass index 30.3 (4.1kg/m 2 )) were recruited from a TKA waiting list. Three-dimensional gait analysis was performed at self-selected walking speed. Comparisons were made between men and women, and overweight (body mass index (BMI) 25.0-29.9kg/m 2 ) and class I obese (BMI 30.0-34.9kg/m 2 ) participants. Biomechanical outcomes included absolute and body size-adjusted peak knee adduction moment (KAM), KAM impulse, peak knee flexion moment, as well as peak knee flexion and varus-valgus angles, peak varus-valgus thrust, and peak vertical ground reaction force (GRF). Men had a higher absolute peak KAM, KAM impulse and peak GRF compared to women, and this sex-difference in frontal plane moments remained after adjusting for body size. However, when additionally adjusting for static knee alignment, differences disappeared. Knee biomechanics were similar between obesity groups after adjusting for the greater body weight of those with class I obesity. Men had greater KAM and KAM impulse even after adjustment for body size; however adjustment for their more varus knees removed this difference. Obesity group did not influence knee joint kinematics or moments. This suggests sex- and obesity-differences in these variables may not be associated with TKA outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Different association between renal hyperfiltration and mortality by sex.

Science.gov (United States)

Yoo, Kyung Don; Yoon, Hyung-Jin; Hwang, Seung-Sik; Heo, Nam Ju; Chin, Ho Jun; Yang, Seung Hee; Joo, Kwon Wook; Kim, Yon Su; Lee, Hajeong

2017-10-01

Renal hyperfiltration (RHF) is a marker of early kidney injury that was recently shown to be a novel marker of mortality. However, it has no clear definition. In this study, we suggested an age- and sex-adjusted RHF definition and explored the association between RHF and mortality by sex. We analyzed data from individuals receiving routine health examinations from 1995 to 2009. RHF was defined as an estimated glomerular filtration rate over the 95th percentile matched for age and sex. A total of 114 966 individuals were included. During the 75-month of observation period, 2559 (2.2%) participants died. Among those, 71.4% were men. Because sex and RHF had a significant interaction for mortality (P for interaction sex. RHF was related to lower body weight and a higher proportion of cigarette smoking in men, whereas these relationships were not found in women. In the Kaplan-Meier curve, RHF was associated with higher mortality rate than non-RHF in both sexes, but this relationship was more prominent in men. In the multivariate analysis, RHF remained as an independent risk factor for all-cause mortality even after adjustment for confounding in men (hazard ratio, 1.34; 95% confidence interval, 1.12-1.59; P = 0.001). In women, RHF was not associated with increased mortality. We demonstrated that RHF was a significant risk factor for mortality in men but not in women. The mechanisms and clinical implications of these different associations according to sex require a further clarification. © 2016 Asian Pacific Society of Nephrology.

Bioaccumulation of lead, mercury, and cadmium in the greater white-toothed shrew, Crocidura russula, from the Ebro Delta (NE Spain); Sex- and age-dependent variation

Energy Technology Data Exchange (ETDEWEB)

Sanchez-Chardi, Alejandro [Departament de Biologia Animal (Vertebrats), Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 645, 08028 Barcelona (Spain)]. E-mail: a.sanchez.chardi@ub.edu; Lopez-Fuster, Maria Jose [Departament de Biologia Animal (Vertebrats), Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 645, 08028 Barcelona (Spain); Nadal, Jacint [Departament de Biologia Animal (Vertebrats), Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 645, 08028 Barcelona (Spain)

2007-01-15

We quantified bioaccumulation of lead, mercury, and cadmium in bones from 105 greater white-toothed shrews (Crocidura russula) collected at the Ebro Delta, a polluted area, and the Medas Islands, a control site. Lead and mercury levels varied with site, age, and sex, although statistical significances depended on each factor. Globally, shrews from the polluted area exhibited significantly higher concentrations of Pb and Hg. Increment of Pb with age was particularly remarkable in wetland animals and was interpreted in relation to human activities, namely hunting. Unlike males, females from the Ebro Delta maintained low Hg levels, which were associated with gestation and lactation. Cadmium levels did not differ between sites, sexes, or ages. This study provides the first data on heavy metals in mammals from this wetland and suggests that C. russula is a good bioindicator of metal pollution. We concluded that sex and age may represent an important source of variation in the bioaccumulation of these metals in wild populations. - Bioaccumulation patterns of Pb and Hg reveal sex and age-related differences in the large bones of the greater white-toothed shrew from a polluted Mediterranean wetland.

The intersection of sex, marital status, and cardiovascular risk factors in shaping stroke incidence: results from the health and retirement study.

Science.gov (United States)

Maselko, Joanna; Bates, Lisa M; Avendaño, Mauricio; Glymour, M Maria

2009-12-01

To examine the role of sex and marital status in the distribution and consequences of cardiovascular risk factors for stroke. Longitudinal cohort. U.S. national sample, community based. U.S. adults aged 50 and older and their spouses. Health and Retirement Study (HRS) participants born between 1900 and 1947 (N=22,818), aged 50 and older, and stroke-free at baseline were followed an average of 9.4 years for self- or proxy-reported stroke (2,372 events). Financial resources, behavioral risk factors, and cardiovascular conditions were used to predict incident stroke in Cox proportional hazard models stratified according to sex and marital status (married, widowed, divorced or separated, or never married). Women were less likely to be married than men. The distribution of risk factors differed according to sex and marital status. Men had higher incident stroke rates than women, even after full risk factor adjustment (hazard ratio (HR)=1.22, 95% confidence interval (CI)=1.11-1.34). For both sexes, being never married or widowed predicted greater risk, associations that were attenuated after adjustment for financial resources. Widowed men had the highest risk (HR=1.40, 95% CI=1.12-1.74 vs married women). Lower income and wealth were associated with similarly high risk across subgroups, although this risk factor especially affected unmarried women, with this group reporting the lowest income and wealth levels. Most other risk factors had similar HRs across subgroups, although moderate alcohol use did not predict lower stroke risk in unmarried women. Stroke incidence and risk factors vary substantially according to sex and marital status. It is likely that gendered social experiences, such as marriage and socioeconomic disadvantage, mediate pathways linking sex and stroke.

Offer of financial incentives for unprotected sex in the context of sex work.

Science.gov (United States)

Johnston, Caitlin L; Callon, Cody; Li, Kathy; Wood, Evan; Kerr, Thomas

2010-03-01

Commercial sex workers (CSW) are often portrayed as vectors of disease transmission. However, the role clients play in sexual risk taking and related decision making has not been thoroughly characterised. Participants were drawn from the Vancouver Injection Drug Users Study, a longitudinal cohort. Analyses were restricted to those who reported selling sex between June 2001 and December 2005. Using multivariate generalised estimating equation, we evaluated the prevalence of and factors associated with being offered money for sex without a condom. A total of 232 CSW were included in the analyses, with 73.7% reporting being offered more money for condom non-use, and 30.6% of these CSW accepting. Variables independently associated with being offered money for sex without a condom included daily speedball use [adjusted odds ratio (AOR) = 1.21, 95% confidence interval (CI): 0.23-0.62], daily crack smoking (AOR = 1.51, 95% CI: 1.04-2.19), daily heroin injection (AOR = 1.76, 95% CI: 1.27-2.43) and drug use with clients (AOR = 3.22, 95% CI: 2.37-4.37). Human immunodeficiency virus seropositivity was not significant (AOR = 0.98, 95% CI: 0.67-1.44). Findings highlight the role clients play in contributing to unprotected sex through economic influence and exploitation of CSW drug use. HIV serostatus has no bearing on whether more money is offered for sex without a condom. Novel interventions should target both CSW and clients.

Effect of estradiol-17β on the sex ratio, growth and survival of juvenile common snook (Centropomus undecimalis)

OpenAIRE

Cristina Vaz Avelar de Carvalho; Gabriel Passini; Wanessa de Melo Costa; Beatriz Nunes Vieira; Vinicius Ronzani Cerqueira

2014-01-01

Sex control in fish is a promising technique for aquaculture, since it gives advantages associated with one sex. The aim of this study was to investigate the feminization of common snook (Centropomus undecimalis) by oral administration of two doses of estradiol-17β (50 and 100 mg E2 kg-1 feed) and control treatment for 45 days and to evaluate their effects on the sex ratio, growth and survival of common snook juveniles. After this period, fish were fed only with commercial feed without hormon...

Influence of postzygotic reproductive isolation on the interspecific transmission of the paternal sex ratio chromosome in Trichogramma

NARCIS (Netherlands)

Jeong, G.S.; Stouthamer, R.

2006-01-01

The paternal sex ratio (PSR) chromosome is a supernumerary chromosome that causes the destruction of the paternal chromosome set in the first mitosis in a fertilized egg. It is known from parasitoid wasps in the genera Nasonia and Trichogramma (Hymenoptera). In these haplodiploids, the egg

The origin of a selfish B chromosome triggering paternal sex ratio in the parasitoid wasp Trichogramma kaykai

NARCIS (Netherlands)

Vugt, van J.J.F.A.; Jong, de J.H.S.G.M.; Stouthamer, R.

2009-01-01

This study uses molecular and cytogenetic methods to determine the origin of a B chromosome in some males of the wasp Trichogramma kaykai. This so-called paternal sex ratio (PSR) chromosome transmits only through sperm and shortly after fertilization triggers degeneration of the paternal genome,

Second to fourth digit ratio (2D:4D and concentrations of circulating sex hormones in adulthood

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Morris Howard A

2011-04-01

Full Text Available Abstract Background The second to fourth digit ratio (2D:4D is used as a marker of prenatal sex hormone exposure. The objective of this study was to examine whether circulating concentrations of sex hormones and SHBG measured in adulthood was associated with 2D:4D. Methods This analysis was based on a random sample from the Melbourne Collaborative Cohort Study. The sample consisted of of 1036 men and 620 post-menopausal women aged between 39 and 70 at the time of blood draw. Concentrations of circulating sex hormones were measured from plasma collected at baseline (1990-1994, while digit length was measured from hand photocopies taken during a recent follow-up (2003-2009. The outcome measures were circulating concentrations of testosterone, oestradiol, dehydroepiandrosterone sulphate, androstenedione, Sex Hormone Binding Globulin, androstenediol glucoronide for men only and oestrone sulphate for women only. Free testosterone and oestradiol were estimated using standard formulae derived empirically. Predicted geometric mean hormone concentrations (for tertiles of 2D:4D and conditional correlation coefficients (for continuous 2D:4D were obtained using mixed effects linear regression models. Results No strong associations were observed between 2D:4D measures and circulating concentrations of hormones for men or women. For males, right 2D:4D was weakly inversely associated with circulating testosterone (predicted geometric mean testosterone was 15.9 and 15.0 nmol/L for the lowest and highest tertiles of male right 2D:4D respectively (P-trend = 0.04. There was a similar weak association between male right 2D:4D and the ratio of testosterone to oestradiol. These associations were not evident in analyses of continuous 2D:4D. Conclusions There were no strong associations between any adult circulating concentration of sex hormone or SHGB and 2D:4D. These results contribute to the growing body of evidence indicating that 2D:4D is unrelated to adult sex

Effect of semen quality on human sex ratio in in vitro fertilization and intracytoplasmic sperm injection: an analysis of 27,158 singleton infants born after fresh single-embryo transfer.

Science.gov (United States)

Arikawa, Mikiko; Jwa, Seung Chik; Kuwahara, Akira; Irahara, Minoru; Saito, Hidekazu

2016-04-01

To evaluate the effect of semen quality on human sex ratio in in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). Retrospective cohort study. Not applicable. A total of 27,158 singleton infants born between 2007 and 2012 after fresh single-embryo transfer. None. Proportion of male infants among liveborn infants. There were 14,996 infants born after IVF, 12,164 infants born after ICSI with ejaculated sperm, and 646 infants born after ICSI with nonejaculated sperm. The sex ratio of IVF was 53.1% (95% confidence interval [CI], 52.3-53.9); the sex ratio of ICSI with ejaculated and nonejaculated sperm demonstrated as statistically significant reduction (48.2%; 95% CI, 47.3-49.1 and 47.7%; 95% CI, 43.8-51.6, respectively). In IVF, lower sperm motility, including asthenozoospermia (sperm motility ratio compared with normal sperm (51.0%; 95% CI, 48.6-53.3 vs. 53.4%; 95% CI, 52.5-54.3). In ICSI with ejaculated sperm, there was no association between sperm motility and sex ratio. Sperm concentration was not associated with sex ratio in both IVF and ICSI. In IVF, lower sperm motility was associated with a statistically significant reduction in sex ratio; ICSI with either ejaculated or nonejaculated sperm was associated with a statistically significant reduction in sex ratio regardless of semen quality. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

The impact of age and sex adjusted body mass index (ISO-BMI) in obese versus non-obese children and adolescents with cholecystectomy.

Science.gov (United States)

Kiuru, Eveliina; Kokki, Hannu; Juvonen, Petri; Lintula, Hannu; Paajanen, Hannu; Gissler, Mika; Eskelinen, Matti

2014-01-01

The impact of the age and sex adjusted body mass index (ISO-BMI) in the obese vs. non-obese children and adolescents with cholecystectomy for cholelithias is rarely reported. The national database was searched for cholecystectomies performed in paediatric patients between 1997 and 2011, and the 59 paediatric and adolescent patients having cholecystectomy in the Kuopio University Hospital district were divided in two groups by age and sex adjusted BMI (ISO-BMI) using the cut-off point of overweight (ISO-BMI 25 kg/m(2)) based on the Finnish growth standards. Nationwide a total of 840 cholecystectomies were performed during the 15 years study period in Finland, most of which included females (77%), resulting in a mean of annual frequency of 4.8 (range: 3.9-6.1) procedures/100,000 population. In the study sample, most of the patients with the cholelithiasis were female (50/59, 85%). The gender distribution was equal among the younger patients, but among adolescents 6/52 (12%) of the patients with cholelithiasis were boys and 46/52 (88%) of the patients with cholelithiasis were girls. Obesity did not affect on operative parameters. The median operative time was 70 min (range, 30-155) and 66 min (44-130) in the high ISO-BMI-group. The recovery was similar in the two groups: the median length of hospital stay was 4 days in both groups. The patients in the low ISO-BMI-group vs. high ISO-BMI-group had a trend of higher serum bilirubin (p=0.16) and serum AFOS values (p=0.19). In the histological examination of the gallbladders 19/28 (68%) patients in the low ISO-BMI-group had inflammation vs. 26/31 (84%) patients in the high ISO-BMI-group (p=0.15). Our results between obese and non-obese children and adolescents with cholelithiasis are not statistically significant. The obese adolescents with female gender are in greater risk for cholelithiasis. Copyright © 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

The ecology of sex explains patterns of helping in arthropod societies.

Science.gov (United States)

Davies, Nicholas G; Ross, Laura; Gardner, Andy

2016-08-01

Across arthropod societies, sib-rearing (e.g. nursing or nest defence) may be provided by females, by males or by both sexes. According to Hamilton's 'haplodiploidy hypothesis', this diversity reflects the relatedness consequences of diploid vs. haplodiploid inheritance. However, an alternative 'preadaptation hypothesis' instead emphasises an interplay of ecology and the co-option of ancestral, sexually dimorphic traits for sib-rearing. The preadaptation hypothesis has recently received empirical support, but remains to be formalised. Here, we mathematically model the coevolution of sex-specific helping and sex allocation, contrasting these hypotheses. We find that ploidy per se has little effect. Rather, the ecology of sex shapes patterns of helping: sex-specific preadaptation strongly influences who helps; a freely adjustable sex ratio magnifies sex biases and promotes helping; and sib-mating, promiscuity, and reproductive autonomy also modulate the sex and abundance of helpers. An empirical survey reveals that patterns of sex-specific helping in arthropod taxa are consistent with the preadaptation hypothesis. © 2016 The Authors. Ecology Letters published by CNRS and John Wiley & Sons Ltd.

Masculine sex ratios, population age structure and the potential spread of HIV in China

OpenAIRE

M. Giovanna Merli; Sara Hertog

2010-01-01

There is much speculation regarding the contribution of China's changing demography to the spread of HIV/AIDS. We employ a bio-behavioral macrosimulation model of the heterosexual spread of HIV/AIDS to evaluate the roles that China's unique demographic conditions -- (1) masculine sex ratios at birth and (2) a population age structure that reflects rapid fertility decline since the 1970's -- play in altering the market for sexual partners, thereby potentially fueling an increase...

Sexually transmitted infections, sexual risk behavior, and intimate partner violence among African American adolescent females with a male sex partner recently released from incarceration.

Science.gov (United States)

Swartzendruber, Andrea; Brown, Jennifer L; Sales, Jessica M; Murray, Colleen C; DiClemente, Ralph J

2012-08-01

Social networks directly and indirectly influence sexually transmitted infections (STIs) risk. The objective was to explore associations between sex with a male recently released from incarceration and sexual risk and intimate partner violence (IPV) among African American adolescent females. Sociodemographic, psychosocial, and sexual behavior data were collected at baseline, 6, and 12 months from African American females, aged 15-21 years, participating in an HIV/STI prevention trial. Among 653 participants with ≥1 follow-up assessments, generalized estimating equations tested associations during follow-up between having a recently released partner and STI acquisition, sexual risk behaviors, and IPV, adjusting for age, treatment assignment, and corresponding baseline measure. Eighty-three (13.6%) participants had a recently released partner at 6 months and 56 (9.3%) at 12 months. Participants with a recently released partner were more likely to have the following: vaginal (adjusted odds ratio [AOR]: 5.48), anal (AOR: 2.43), and oral (AOR: 1.51) sex, a casual partner (AOR: 1.66), sex while high/drunk (AOR: 1.57) or with a high/drunk partner (AOR: 2.27); use condoms inconsistently (AOR: .58); acquire Chlamydia (AOR: 1.80), and experience emotional (AOR: 4.09), physical (AOR: 2.59), or sexual abuse (AOR: 4.10) by a boyfriend. They had a greater number of sex partners, lower partner communication and refusal self-efficacy, were high/drunk during sex more frequently, and used condoms during oral sex less frequently. A recently released sex partner is associated with sexual risk and IPV among African American adolescent females. Prevention programs should inform adolescents about potential risks associated with recently released partners as well as provide adolescents with skills to establish and maintain healthy sexual relationships. Copyright © 2012 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Genetic Diversity of the Invasive Gall Wasp Leptocybe invasa (Hymenoptera: Eulophidae) and of its Rickettsia Endosymbiont, and Associated Sex-Ratio Differences

Science.gov (United States)

Nugnes, Francesco; Gebiola, Marco; Monti, Maurilia Maria; Gualtieri, Liberata; Giorgini, Massimo; Wang, Jianguo; Bernardo, Umberto

2015-01-01

The blue-gum chalcid Leptocybe invasa Fisher & LaSalle (Hymenoptera: Eulophidae) is a gall wasp pest of Eucalyptus species, likely native to Australia. Over the past 15 years it has invaded 39 countries on all continents where eucalypts are grown. The worldwide invasion of the blue gum chalcid was attributed to a single thelytokous morphospecies formally described in 2004. Subsequently, however, males have been recorded in several countries and the sex ratio of field populations has been found to be highly variable in different areas. In order to find an explanation for such sex ratio differences, populations of L. invasa from a broad geographical area were screened for the symbionts currently known as reproductive manipulators, and both wasps and symbionts were genetically characterized using multiple genes. Molecular analyses suggested that L. invasa is in fact a complex of two cryptic species involved in the rapid and efficient spread of the wasp, the first recovered from the Mediterranean region and South America, the latter from China. All screened specimens were infected by endosymbiotic bacteria belonging to the genus Rickettsia. Two closely related Rickettsia strains were found, each infecting one of the two putative cryptic species of L. invasa and associated with different average sex ratios. Rickettsia were found to be localized in the female reproductive tissues and transovarially transmitted, suggesting a possible role of Rickettsia as the causal agent of thelytokous parthenogenesis in L. invasa. Implications for the variation of sex ratio and for the management of L. invasa are discussed. PMID:25970681

Genetic Diversity of the Invasive Gall Wasp Leptocybe invasa (Hymenoptera: Eulophidae and of its Rickettsia Endosymbiont, and Associated Sex-Ratio Differences.

Directory of Open Access Journals (Sweden)

Francesco Nugnes

Full Text Available The blue-gum chalcid Leptocybe invasa Fisher & LaSalle (Hymenoptera: Eulophidae is a gall wasp pest of Eucalyptus species, likely native to Australia. Over the past 15 years it has invaded 39 countries on all continents where eucalypts are grown. The worldwide invasion of the blue gum chalcid was attributed to a single thelytokous morphospecies formally described in 2004. Subsequently, however, males have been recorded in several countries and the sex ratio of field populations has been found to be highly variable in different areas. In order to find an explanation for such sex ratio differences, populations of L. invasa from a broad geographical area were screened for the symbionts currently known as reproductive manipulators, and both wasps and symbionts were genetically characterized using multiple genes. Molecular analyses suggested that L. invasa is in fact a complex of two cryptic species involved in the rapid and efficient spread of the wasp, the first recovered from the Mediterranean region and South America, the latter from China. All screened specimens were infected by endosymbiotic bacteria belonging to the genus Rickettsia. Two closely related Rickettsia strains were found, each infecting one of the two putative cryptic species of L. invasa and associated with different average sex ratios. Rickettsia were found to be localized in the female reproductive tissues and transovarially transmitted, suggesting a possible role of Rickettsia as the causal agent of thelytokous parthenogenesis in L. invasa. Implications for the variation of sex ratio and for the management of L. invasa are discussed.

Associations Between Internalized Homophobia and Sexual Risk Behaviors Among Young Black Men Who Have Sex With Men.

Science.gov (United States)

Crosby, Richard A; Salazar, Laura F; Mena, Leandro; Geter, Angelica

2016-10-01

To assess internalized homophobia (IH) and its relationship to sexual risk behaviors and prevalence of sexually transmitted infection (STIs) in a clinic-based sample of young black men who have sex with men (YBMSM). Six hundred YBMSM completed a self-interview and provided specimens for testing. A 7-item scale assessed IH, and 19 sexual risk behaviors were assessed. In adjusted models, compared with men with less IH, those with greater IH were more likely to report: any condomless anal receptive sex (P = 0.01) and sex with women (P < 0.001). Alternatively, men with greater IH were less likely to: discuss acquired immune deficiency syndrome prevention with sex partners (P = 0.009), disclose their same sex sexual behavior to providers (P = 0.01), be tested for human immunodeficiency virus in the past 12 months (P = 0.04), report condomless oral sex (P = 0.049), and test RPR positive (P = 0.01). With some exceptions, IH among YBMSM attending STI clinics may influence their sexual risk behaviors; however, STI prevalence was not associated with this construct.

Reproductive behaviour of female rosy bitterling Rhodeus ocellatus in response to a female-biased operational sex ratio

Czech Academy of Sciences Publication Activity Database

Liao, C.; Yu, D.; Chen, Y.; Reichard, Martin; Liu, H.

2014-01-01

Roč. 151, č. 6 (2014), s. 755-768 ISSN 0005-7959 R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:68081766 Keywords : alternative reproductive behaviour * female aggression * operational sex ratio * bitterling Subject RIV: EG - Zoology Impact factor: 1.230, year: 2014

Interpersonal and structural contexts of intimate partner violence among female sex workers in conflict-affected northern Uganda.

Science.gov (United States)

Erickson, Margaret; Goldenberg, Shira M; Master, Aditi; Muzaaya, Godfrey; Akello, Monica; Braschel, Melissa; Birungi, Josephine; Shannon, Kate

2017-07-06

Intimate partner violence (IPV) is the most prevalent form of violence against women, yet remains under-researched among sex workers in sub-Saharan Africa. We explored the interpersonal and structural determinants of recent IPV among female sex workers in northern Uganda. This analysis drew on data from a community-based cross-sectional study (conducted May 2011-January 2012), involving 379 female sex workers in Gulu, northern Uganda. Using logistic regression and multivariable modeling, we examined the correlates of recent male-perpetrated physical or sexual IPV. Of 379 women with noncommercial partners, 59 percent reported having experienced recent moderate/severe physical or sexual IPV. Reporting recent client violence (adjusted odds ratio (AOR): 3.67; 95 percent confidence interval [CI]: 2.31-5.83), doing what their partner wanted (AOR: 2.46; 95 percent CI: 1.46-4.13), and forced sexual debut (AOR: 1.92; 95 percent CI: 1.20-3.05) were independently associated with moderate/severe IPV; recent police arrest and/or incarceration were/was marginally significantly associated with IPV (AOR: 2.25; 95 percent CI: 0.86-5.88, p = 0.097). Greater odds of IPV among sex workers were associated with recent workplace violence, forced sexual debut, and gendered power dynamics favoring male partner control. Programs and policies promoting the safety and health of marginalized women and addressing gender dynamics and violence are needed.

HOW TO STEER THE TRANSMISSION RATIO OF PLANETARY CONTINUOUSLY ADJUSTABLE GEAR TRAIN

Directory of Open Access Journals (Sweden)

A. M. Dankov

2016-01-01

Full Text Available The known attempts to create a continuously-adjustable gear train with solid gears have led to development of some so-called adaptive gears. The most structurally simple version of continuously- adjustable gear train is a two-wheel planetary gear. It is an obvious fact that an active regulation of gear ratio for the gear should be based on the presence of con- trolled elements (parameters and a mechanism for their control. In respect of the mentioned gear one of the controlled elements that is a compound central toothed gear has such controlled parameter as a nominal pitch diameter. In this case it can rotate or remain motionless. Other controlled element which is a planetary carrier has its own radius as a controlled parameter and makes a rotary motion with a great speed of a leading element. The purpose of the control mechanism is to ensure radial displacement of central toothed gear and planet gear sectors in the working gear. The paper describes the mechanism modifications and considers two variants for transfer of control action from its source to an object to be controlled. The transfer is ensured by mechanical gears (two variants and hydraulics.

E2,M1 multipole mixing ratios in even--even nuclei, A greater than or equal to 152

International Nuclear Information System (INIS)

Krane, K.S.

1975-01-01

A survey is presented of E2,M1 mixing ratios of gamma-ray transitions in even-even nuclei with mass numbers A greater than or equal to 152. Angular distribution and correlation data from the literature are analyzed in terms of a consistent choice of the phase relationship between the E2 and M1 matrix elements. The cutoff date for the literature was June 1975. Based on an average of the experimental results from the literature, a recommended value of the E2,M1 mixing ratio for each transition is included

A framework for analyzing sex-selective abortion: the example of changing sex ratios in Southern Caucasus

Science.gov (United States)

Hohmann, Sophie A; Lefèvre, Cécile A; Garenne, Michel L

2014-01-01

The paper proposes a socioeconomic framework of supply, demand, and regulation to explain the development of sex-selective abortion in several parts of the world. The framework is then applied to three countries of southern Caucasus (Armenia, Azerbaijan, and Georgia) where sex-selective abortion has developed since the collapse of the Soviet Union. The authors argue that sex-selective abortion cannot be explained simply by patriarchal social systems, sex discrimination, or son preference. The emphasis is put on the long-term acceptability of abortion in the region, on acceptability of sex-screening by both the medical establishment and by the population, on newly imported techniques of sex-screening, and on the changing demand for children associated with the major economic and social changes that followed the dismantlement of the Soviet Union. PMID:25349481

Updating Financial Ratios: Seeking Greater Understanding, Precision, and Practicality.

Science.gov (United States)

Jenny, Hans H.; Minter, W. John

1993-01-01

Modifications to current methods of calculating and reporting financial ratios are outlined for college managers. The modified ratios, felt to be more realistic, are illustrated with applications in three areas: (1) student revenues; (2) endowment and other investment income; and (3) public and private gifts, grants, and contracts revenue. (MSE)

Influences of supplemental feeding on winter elk calf:cow ratios in the southern Greater Yellowstone Ecosystem

Science.gov (United States)

M. Foley, Aaron; Cross, Paul C.; Christianson, David A; Scurlock, Brandon M.; Creely, Scott

2015-01-01

Several elk herds in the Greater Yellowstone Ecosystem are fed during winter to alleviate interactions with livestock, reduce damage to stored crops, and to manage for high elk numbers. The effects of supplemental feeding on ungulate population dynamics has rarely been examined, despite the fact that supplemental feeding is partially justified as necessary for maintaining or enhancing population growth rates. We used linear regression to assess how the presence of feedgrounds, snowpack, summer rainfall, indices of grizzly bear density and wolves per elk, elk population trend counts, brucellosis seroprevalence, and survey date were correlated with midwinter calf:cow ratios, a metric correlated with population growth, from 1983–2010 from 12 ecologically similar elk herd units (7 fed and 5 unfed) in Wyoming, USA. Our statistical approach allowed for rigorous tests of the hypotheses that supplemental feeding had positive effects on calf:cow ratios and reduced sensitivity of calf:cow ratios to bottom-up limitation relative to top-down limitation from native predators. Calf:cow ratios generally declined across all herd units over the study period and varied widely among units with feedgrounds. We found no evidence that the presence of feedgrounds had positive effects on midwinter calf:cow ratios in Wyoming. Further, fed elk showed stronger correlations with environmental factors, whereas calf:cow ratios for unfed elk showed stronger correlations with predator indices. Although we found no consistent association between winter feeding and higher calf:cow ratios, we did not assess late winter mortality and differences in human offtake between fed and unfed regions, which remain a priority for future research. 

Status hierarchy, attractiveness hierarchy and sex ratio : Three contextual factors explaining the status-aggression link among adolescents

NARCIS (Netherlands)

Zwaan, Michiel; Dijkstra, Jan; Veenstra, René

The moderating effects of three specific conditions (status hierarchy, attractiveness hierarchy and sex ratio) on the link between status (popularity) and physical and relational aggression were examined in a large sample of adolescent boys (N = 1,665) and girls (N = 1,637) (M age = 13.60). In line

Reproductive seasonality, sex ratio and philopatry in Argentina's common vampire bats

Science.gov (United States)

Delpietro, H. A.; Russo, R. G.; Lord, R. D.; Delpietro, G. L.

2017-01-01

Common vampire bats (Desmodus rotundus) are a key rabies vector in South America. Improved management of this species requires long-term, region-specific information. To investigate patterns of demography and dispersal, we analysed 13 642 captures of common vampire bats in Northern Argentina from the period 1969–2004. In contrast with findings from more tropical regions, we found reproductive seasonality with peak pregnancy in September and peak lactation in February. Curiously, sex ratios were consistently male-biased both in maternity roosts and at foraging sites. Males comprised 57% of 9509 adults caught at night, 57% of 1078 juveniles caught at night, 57% of 603 juveniles caught in roosts during the day, and 55% of 103 newborns and mature fetuses. Most observed roosts were in man-made structures. Movements of 1.5–54 km were most frequent in adult males, followed by young males, adult females and young females. At night, males visited maternity roosts, and non-pregnant, non-lactating females visited bachelor roosts. Males fed earlier in the night. Finally, we report new longevity records for free-ranging vampire bats: 16 and 17 years of age for a female and male, respectively. Our results are consistent with model predictions that sex-biased movements might play a key role in rabies transmission between vampire bat populations. PMID:28484615

Reproductive seasonality, sex ratio and philopatry in Argentina's common vampire bats.

Science.gov (United States)

Delpietro, H A; Russo, R G; Carter, G G; Lord, R D; Delpietro, G L

2017-04-01

Common vampire bats ( Desmodus rotundus ) are a key rabies vector in South America. Improved management of this species requires long-term, region-specific information. To investigate patterns of demography and dispersal, we analysed 13 642 captures of common vampire bats in Northern Argentina from the period 1969-2004. In contrast with findings from more tropical regions, we found reproductive seasonality with peak pregnancy in September and peak lactation in February. Curiously, sex ratios were consistently male-biased both in maternity roosts and at foraging sites. Males comprised 57% of 9509 adults caught at night, 57% of 1078 juveniles caught at night, 57% of 603 juveniles caught in roosts during the day, and 55% of 103 newborns and mature fetuses. Most observed roosts were in man-made structures. Movements of 1.5-54 km were most frequent in adult males, followed by young males, adult females and young females. At night, males visited maternity roosts, and non-pregnant, non-lactating females visited bachelor roosts. Males fed earlier in the night. Finally, we report new longevity records for free-ranging vampire bats: 16 and 17 years of age for a female and male, respectively. Our results are consistent with model predictions that sex-biased movements might play a key role in rabies transmission between vampire bat populations.

Sibling relationship quality and Mexican-origin adolescents' and young adults' familism values and adjustment

Science.gov (United States)

Killoren, Sarah E.; De Jesús, Sue A. Rodríguez; Updegraff, Kimberly A.; Wheeler, Lorey A.

2015-01-01

We examined profiles of sibling relationship qualities in 246 Mexican-origin families living in the United States using latent profile analyses. Three profiles were identified: Positive, Negative and Affect-Intense. Links between profiles and youths’ familism values and adjustment were assessed using longitudinal data. Siblings in the Positive profile reported the highest familism values, followed by siblings in the Affect-Intense profile and, finally, siblings in the Negative profile. Older siblings in the Positive and Affect-Intense profiles reported fewer depressive symptoms than siblings in the Negative profile. Further, in the Positive and Negative profiles, older siblings reported less involvement in risky behaviors than younger siblings. In the Negative profile, younger siblings reported greater sexual risk behaviors in late adolescence than older siblings; siblings in opposite-sex dyads, as compared to same-sex dyads, engaged in riskier sexual behaviors. Our findings highlight sibling relationship quality as promotive and risky, depending on sibling characteristics and adjustment outcomes. PMID:28239217

[Sex ratio and environmental influence on population growth rate of Callinectes bellicosus (Decapoda: Portunidae) in the Gulf of California].

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Rodríguez-Félix, Demetrio; Cisneros-Mata, Miguel Angel; Aragón-Noriega, Eugenio Alberto; Arreola-Lizárraga, José Alfredo

2016-09-01

The brown swimming crab (Callinectes bellicosus) is an economically important species in the Gulf of California, and its fishing activity, held in Sonora from 1986, has been affected by a 20-year declining trend in its biomass. With the aim to understand the possible reasons of this species population changes along time, we estimated population growth rate (r) and sex ratio of C. bellicosus, and combined them with three parameters describing its habitat: sea temperature, wetland extension and habitat size in four areas along the coast of Sonora. For this, monthly mean sex ratio was estimated from crabs samples obtained from commercial catches during 1998-2002 and 2012; mean sea surface temperature for the spawning period (May-August) were derived from remote sensors for the same years; while wetland coverages were obtained from published reports, and habitat size was estimated as the fishing surface. For each area, r was estimated using a method developed for limited data situations using commercial landings (t) from 1986-2013. With data from the four areas, simple and multiple linear regression models were developed to ascertain theoretical sensitivities of r to variations in sex ratio and environmental parameters. A total of 24 556 crabs were sampled; males dominated (68.8 %) over females during the study period and in all areas; a cluster analysis identified two groups according to sex ratio: a Northern group with zones 1 and 2, and a Southern group with zones 3 and 4. r values were different in all zones (P0.995). Both the estimated data and sensitivity analyses suggest the existence of a direct and positive dependence of r on the proportion of female crabs and wetland size. We hypothesize that excess fishing of females caused the declining biomass trend of the brown swimming crab in Sonora, and concluded on the convenience of implementing harvest refugia inside coastal wetlands to protect females during the spawning season.

Adjustment of the ratio of Ca/P in the ceramic coating on Mg alloy by plasma electrolytic oxidation

International Nuclear Information System (INIS)

Yao Zhongping; Li Liangliang; Jiang Zhaohua

2009-01-01

The ceramic coatings containing Ca and P were prepared on AZ91D Mg alloy by plasma electrolytic oxidation technique in NaOH system and Na 2 SiO 3 system, respectively. The phase composition, morphology and the element distribution of the coatings was studied by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The corrosion resistance of the coatings was examined by polarizing curve methods in a 0.9% NaCl solution. In NaOH system, there were a large number of micro-holes distributing evenly on the surface of the coating, and the coating was mainly composed of Mg, Al, P and Ca. In Na 2 SiO 3 system, the micro-holes in the coatings were reduced greatly in number and the distribution of the micro-holes was uneven, and the coating was mainly composed of Mg, Al, Si, P and Ca. The ratio of Ca/P in the coating can be controlled by the adjustment of the technique parameters to a certain extent. The adjustment of the concentration of Ca 2+ in the electrolyte was an effective method to change the ratio of Ca/P in the coating in both systems; the reaction time and the working voltage for the adjustment of the ratio of Ca/P in the coating was more suitable for the NaSi 2 O 3 system than the NaOH system. The polarizing curve tests showed the coatings improved the corrosion resistance of the AZ91D Mg alloy in 0.9% NaCl solution by nearly two orders of magnitude.

Sex ratio and breeding of white-lipped peccaries Tayassu pecari (Artiodactyla: Tayassuidae in a Costa Rican rain forest

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Mariana Altrichter

2001-03-01

Full Text Available White-lipped peccaries are non-seasonal breeders in South America, but little is known about their reproduction in Central America. There are few studies about the sex ratio of this species in the field. We studied the reproduction and sex ratio of white-lipped peccaries during 200 hours of field observation of four radiomarked and two unmarked herds, from July 1996 to April 1997, in Corcovado National Park, Costa Rica. Sex ratio data of three additional, radiomarked herds observed in 1998 were also included. We recorded numbers of mountings, presence of newborns and numbers of nursing interactions. The peccaries showed a distinct reproductive seasonality, with one mating peak in February and another in July. The greatest number of newborns and the peak in nursing activity were observed during July and August, when fruit availability for the peccaries was high. The adult sex ratio was significantly female biased (1.4:1 - 1.8:1, also in contrast with South American populations.Los "chanchos cariblancos" Tayassu pecari no son reproductores estacionales en Sur América. En Centro América se conoce muy poco sobre la reproducción de esta especie en la naturaleza. Estudiamos reproducción y la proporción de sexos durante 200 horas de observación de cuatro manadas marcadas con radiocollares y de dos manadas sin marcar, desde julio de 1996 hasta abril de 1997 en el Parque Nacional Corcovado, Costa Rica, agregando datos de proporción sexual de tres manadas observadas en 1998. Registramos el número de cópulas y de amamantamientos, así como la presencia de recién nacidos en las manadas. Observamos una marcada estacionalidad en la reproducción, con un pico en el número de cópulas en febrero y otro en julio. La mayor cantidad de recién nacidos y el pico de actividad de amamantamiento fueron en julio y agosto, cuando la disponibilidad de alimento era alta. Entre adultos predominaron numéricamente las hembras (1.4:1 - 1.8:1, lo cual difiere de lo

Status Hierarchy, Attractiveness Hierarchy and Sex Ratio: Three Contextual Factors Explaining the Status-Aggression Link among Adolescents

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Zwaan, Michiel; Dijkstra, Jan Kornelis; Veenstra, Rene

2013-01-01

The moderating effects of three specific conditions (status hierarchy, attractiveness hierarchy and sex ratio) on the link between status (popularity) and physical and relational aggression were examined in a large sample of adolescent boys ("N" = 1,665) and girls ("N" = 1,637) ("M" age = 13.60). In line with the…

Sex Differences in Cardiovascular Mortality in Diabetics and Nondiabetic Subjects: A Population-Based Study (Italy

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Paola Ballotari

2015-01-01

Full Text Available The objective of this study is to assess the impact of diabetes on cardiovascular mortality, focusing on sex differences. The inhabitants of Reggio Emilia province on December 31, 2009, aged 20–84 were followed up for three years for mortality. The exposure was determined using Reggio Emilia diabetes register. The age-adjusted death rates were estimated as well as the incidence rate ratios using Poisson regression model. Interaction terms for diabetes and sex were tested by the Wald test. People with diabetes had an excess of mortality, compared with nondiabetic subjects (all cause: IRR = 1.68; 95%CI 1.60–1.78; CVD: IRR = 1.61; 95%CI 1.47–1.76; AMI: IRR = 1.59; 95%CI 1.27–1.99; renal causes: IRR = 1.71; 95%CI 1.22–2.38. The impact of diabetes is greater in females than males for all causes (P=0.0321 and for CVD, IMA, and renal causes. Further studies are needed to investigate whether the difference in cardiovascular risk profile or in the quality of care delivered justifies the higher excess of mortality in females with diabetes compared to males.

Sex differences in cardiovascular mortality in diabetics and nondiabetic subjects: a population-based study (Italy).

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Ballotari, Paola; Ranieri, Sofia Chiatamone; Luberto, Ferdinando; Caroli, Stefania; Greci, Marina; Giorgi Rossi, Paolo; Manicardi, Valeria

2015-01-01

The objective of this study is to assess the impact of diabetes on cardiovascular mortality, focusing on sex differences. The inhabitants of Reggio Emilia province on December 31, 2009, aged 20-84 were followed up for three years for mortality. The exposure was determined using Reggio Emilia diabetes register. The age-adjusted death rates were estimated as well as the incidence rate ratios using Poisson regression model. Interaction terms for diabetes and sex were tested by the Wald test. People with diabetes had an excess of mortality, compared with nondiabetic subjects (all cause: IRR = 1.68; 95%CI 1.60-1.78; CVD: IRR = 1.61; 95%CI 1.47-1.76; AMI: IRR = 1.59; 95%CI 1.27-1.99; renal causes: IRR = 1.71; 95%CI 1.22-2.38). The impact of diabetes is greater in females than males for all causes (P = 0.0321) and for CVD, IMA, and renal causes. Further studies are needed to investigate whether the difference in cardiovascular risk profile or in the quality of care delivered justifies the higher excess of mortality in females with diabetes compared to males.

Polybrominated diphenyl ethers affect the reproduction and development, and alter the sex ratio of zebrafish (Danio rerio)

International Nuclear Information System (INIS)

Han, X.B.; Yuen, Karen W.Y.; Wu, Rudolf S.S.

2013-01-01

Polybrominated diphenyl ethers (PBDEs) have been commonly used as flame retardants and now become ubiquitous in the global environment. Using zebrafish as a model, we tested the hypothesis that PBDEs may affect the reproduction and development of fish. Zebrafish were exposed to environmentally relevant concentrations of DE-71 (a congener of PBDE commonly found in the environment) throughout their whole life cycle, and the effects of DE-71 on gonadal development, gamete quality, fertilization success, hatching success, embryonic development and sex ratio were investigated. Despite gonadal development was enhanced, reductions in spawning, fertilization success, hatching success and larval survival rate were evident, while significant increases in malformation and percentage of male were also observed in the F1 generation. Our laboratory results suggest that PBDEs may pose a risk to reproductive success and alter the sex ratio of fish in environments highly contaminated with PBDEs. -- Highlights: •Zebrafish were exposed to PBDE from eggs to adults. •An increase in Gonadal-Somatic Index and enhanced gonadal development was enhanced. •Fertilization and hatching successes were reduced, while malformation was increased. •PBDE alters sex differentiation, leading to a male biased F1 population. •Environmental relevant concentrations of PBDE threaten natural fish populations. -- PBDE reduces fertilization and hatching successes, causes malformation and leads to a male biased F1 generation in fish

Race and Sex Differences of Long-Term Blood Pressure Profiles From Childhood and Adult Hypertension: The Bogalusa Heart Study.

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Shen, Wei; Zhang, Tao; Li, Shengxu; Zhang, Huijie; Xi, Bo; Shen, Hongbing; Fernandez, Camilo; Bazzano, Lydia; He, Jiang; Chen, Wei

2017-07-01

This study aims to characterize longitudinal blood pressure (BP) trajectories from childhood in black-white and sex groups and examine the association between childhood level-independent trajectories of BP and adult hypertension. The longitudinal cohort consisted of 2732 adults who had body mass index and BP measured 4 to 15 times from childhood (4-19 years) to adulthood (20-51 years). Model-estimated levels and linear slopes of BP and body mass index at childhood age points were calculated at 1-year intervals using the growth curve parameters and their first derivatives, respectively. Linear and nonlinear curve parameters differed significantly between race-sex groups; BP levels showed race and sex differences 15 years of age onward. Hypertensives had higher long-term BP levels than normotensives in race-sex groups. Although linear and nonlinear slope parameters of BP were race and sex specific, they differed consistently, significantly between hypertension and normotension groups. BP trajectories during young adulthood (20-35 years) were significantly greater in hypertensives than in normotensives; however, the trajectories during middle-aged adulthood (36-51 years) were significantly smaller in hypertensives than in normotensives. Level-independent linear slopes of systolic BP showed significantly negative associations (odds ratio=0.50≈0.76; P hypertension, adjusting for covariates. These associations were consistent across race-sex groups. These observations indicate that adult hypertension originates in childhood, with different longitudinal BP trajectory profiles during young and middle-aged adulthood in black-white and sex groups. Puberty is a crucial period for the development of hypertension in later life. © 2017 American Heart Association, Inc.

Racial and/or Ethnic Differences in Formal Sex Education and Sex Education by Parents among Young Women in the United States.

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Vanderberg, Rachel H; Farkas, Amy H; Miller, Elizabeth; Sucato, Gina S; Akers, Aletha Y; Borrero, Sonya B

2016-02-01

We sought to investigate the associations between race and/or ethnicity and young women's formal sex education and sex education by parents. Cross-sectional analysis of a nationally representative sample of 1768 women aged 15-24 years who participated in the 2011-2013 National Survey of Family Growth. We assessed 6 main outcomes: participants' report of: (1) any formal sex education; (2) formal contraceptive education; (3) formal sexually transmitted infection (STI) education; (4) any sex education by parents; (5) contraceptive education by parents; and (6) STI education by parents. The primary independent variable was self-reported race and/or ethnicity. Nearly all of participants (95%) reported any formal sex education, 68% reported formal contraceptive education, and 92% reported formal STI education. Seventy-five percent of participants reported not having any sex education by parents and only 61% and 56% reported contraceptive and STI education by parents, respectively. US-born Hispanic women were more likely than white women to report STI education by parents (adjusted odds ratio = 1.87; 95% confidence interval, 1.17-2.99). No other significant racial and/or ethnic differences in sex education were found. There are few racial and/or ethnic differences in formal sex education and sex education by parents among young women. Copyright © 2016 North American Society for Pediatric and Adolescent Gynecology. All rights reserved.

Seeking sex partners through the internet and mobile phone applications among men who have sex with men in Taiwan.

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Ko, Nai-Ying; Tseng, Po-Chia; Huang, Yu-Chao; Chen, Yen-Chin; Hsu, Su-Ting

2016-07-01

It has become popular for men who have sex with men (MSM) to use mobile-phone geosocial networking applications (mobile apps) to find sex partners. A cross-sectional online survey was conducted in Taiwan to compare the sexual and substance-use behaviors of MSM seeking sex partners through the internet and mobile apps. Of the 1060 participants, 65.8% used the internet via computer and 37.7% used a mobile app to find sexual partners, while 30.3% used recreational drugs or alcohol in the previous 6 months. MSM who exclusively used mobile apps to seek sex partners were significantly more likely than MSM seeking sex via computer to be older, to have used recreational drugs or alcohol, and to have sex with HIV-positive partners. Additionally, using mobile apps to seek sex partners was significantly associated with having sex with online partners through either mobile apps or computer-based internet use (adjusted odds ratio (AOR), 7.12 [3.87-13.11]), self-reporting as HIV-positive (AOR, 2.24 [1.12-4.12]), using recreational drugs (AOR, 1.67 [1.21-2.32]), having disclosed HIV status to sexual partners (AOR, 1.44 [1.03-2.02]), and having sex with HIV-positive partners (AOR, 1.81 [1.06-3.10]). In conclusion, the mobile apps may serve as a feasible platform for HIV-positive MSM to find other HIV-positive partners.

Determinants of Heterosexual Adolescents Having Sex with Female Sex Workers in Singapore.

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Junice Y S Ng

Full Text Available We assessed the proportion of and socio-ecological factors associated with ever having had sex with female sex workers (FSWs among heterosexual adolescents. We also described the characteristics of the adolescents who reported inconsistent condom use with FSWs.This is a cross-sectional study (response rate: 73% of 300 heterosexually active male adolescents of 16 to 19 years attending a national STI clinic in Singapore between 2009 and 2014. We assessed the ecological factors (individual, parental, peer, school and medial influences and sexual risk behaviors using a self-reported questionnaire. Poisson regression was used to obtain the adjusted prevalence ratios (aPR and confidence intervals (CI.The proportion of heterosexual male adolescents who had ever had sex with FSWs was 39%. Multivariate analysis showed that significant factors associated with ever having had sex with FSWs were sex initiation before 16 years old (aPR 1.79 CI: 1.30-2.46, never had a sexually active girlfriend (aPR 1.75 CI 1.28-2.38, reported lower self-esteem score (aPR 0.96 CI: 0.93-0.98, higher rebelliousness score (aPR 1.03 CI: 1.00-1.07 and more frequent viewing of pornography (aPR 1.47 CI: 1.04-2.09. Lifetime inconsistent condom use with FSWs was 30%.A significant proportion of heterosexual male adolescents attending the public STI clinic had ever had sex with FSWs. A targeted intervention that addresses different levels of influence to this behavior is needed. This is even more so because a considerable proportion of adolescents reported inconsistent condom use with FSWs, who may serve as a bridge of STI transmission to the community. National surveys on adolescent health should include the assessment of frequency of commercial sex visits and condom use with FSWs for long-term monitoring and surveillance.

Data storage on Russian pesticide producers exposed to dioxin. Sex ratios of third generation of Russian cohort

Energy Technology Data Exchange (ETDEWEB)

Amirova, Z.; Kruglov, E. [Environmental Research and Protection Center, Ufa (Russian Federation); Dardynskaia, I. [Univ. of Illinois, School of Public Health, Chicago (United States)

2004-09-15

A cohort of Russian workers who produced 2,4,5-T and 2,4,5-TrCP at a chemical factory in Ufa was brought to light in the papers of A. Schecter, J. Ryan and O. Papke. Dioxin exposure was experimentally confirmed by PCDD/Fs determination in blood samples first for a small group of workers and their children. This study permitted to connect the information of medical institutions about chloracne from which a group of young 2,4,5-T workers suffered in 1965-67 with exposure to dioxin. This report presents the results of the detailed study of the third generation of the Russian cohort (247 workers, 314 children and 260 grandchildren). We also present the data on the sex ratio of the second generation for the initial group enlarged by 25% as compared with the group of workers analyzed by J. Ryan et al. (198 workers and 227 children). Besides, as skewed sex ratio had earlier been stated only for paternal descendants, genealogical branches of the cohort representatives were studied.

On the masculinization of population: The contribution of demographic development -- A look at sex ratios in Sweden over 250 years

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Thomas Spoorenberg

2016-06-01

Full Text Available Background: Almost everywhere, women live longer than men, but the world population includes increasingly more men than women. This fact is observed not only in populations where gender-based discrimination is practised, but also in developed countries like Sweden. Objective: Whereas discrimination against female infants and women is usually given as an explanation for this paradox, demographic development (through improved survival also plays a role. This study examines the largely unnoticed role of demographic development in the masculinization of population, taking the case of Sweden. Methods: Using high-quality data from the Human Mortality Database for Sweden over the last 250 years, changes in the sex ratio at various ages are described and linked to the continuing survival gains achieved over the mortality transition. Results: Thanks to the reduction of secular mortality in Sweden, the natural sex imbalance observed at birth has been progressively prolonged later in life, and the age at which women outnumber men has been postponed to older ages. Similar developments are found in Norway and Denmark. Conclusions: The general decline of mortality is one of humanity's biggest achievements, but the accompanying change in age- and sex-specific survival patterns, coupled with the natural sex imbalance at birth, influences the age and sex composition of a population and, therefore, the sex ratio at successive ages. In a world where each new generation can expect to enjoy a longer life than the previous one, an increasing number of men can also be expected. Contribution: The role of demographic development in the masculinization of population has remained largely unnoticed so far.

Effects of a sex-ratio distorting endosymbiont on mtDNA variation in a global insect pest

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Cook James M

2009-03-01

Full Text Available Abstract Background Patterns of mtDNA variation within a species reflect long-term population structure, but may also be influenced by maternally inherited endosymbionts, such as Wolbachia. These bacteria often alter host reproductive biology and can drive particular mtDNA haplotypes through populations. We investigated the impacts of Wolbachia infection and geography on mtDNA variation in the diamondback moth, a major global pest whose geographic distribution reflects both natural processes and transport via human agricultural activities. Results The mtDNA phylogeny of 95 individuals sampled from 10 countries on four continents revealed two major clades. One contained only Wolbachia-infected individuals from Malaysia and Kenya, while the other contained only uninfected individuals, from all countries including Malaysia and Kenya. Within the uninfected group was a further clade containing all individuals from Australasia and displaying very limited sequence variation. In contrast, a biparental nuclear gene phylogeny did not have infected and uninfected clades, supporting the notion that maternally-inherited Wolbachia are responsible for the mtDNA pattern. Only about 5% (15/306 of our global sample of individuals was infected with the plutWB1 isolate and even within infected local populations, many insects were uninfected. Comparisons of infected and uninfected isofemale lines revealed that plutWB1 is associated with sex ratio distortion. Uninfected lines have a 1:1 sex ratio, while infected ones show a 2:1 female bias. Conclusion The main correlate of mtDNA variation in P. xylostella is presence or absence of the plutWB1 infection. This is associated with substantial sex ratio distortion and the underlying mechanisms deserve further study. In contrast, geographic origin is a poor predictor of moth mtDNA sequences, reflecting human activity in moving the insects around the globe. The exception is a clade of Australasian individuals, which may

Behaviour change and associated factors among female sex workers in Kenya.

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Nyagero, Josephat; Wangila, Samuel; Kutai, Vincent; Olango, Susan

2012-01-01

Initiatives aimed at behaviour change of key populations such as the female sex workers (FSWs) are pivotal in reducing the transmission of HIV. An 8-year implementation research to establish the predictor factors of behaviour change among FSWs in Kenya was initiated by the African Medical Research Foundation (AMREF) with Sida and DfID support. This cross-sectional survey interviewed 159 female sex workers (FSWs) identified through snowball procedure. The measurement of behaviour change was based on: the consistent use of condoms with both regular and non regular clients, reduced number of clients, routine checks for STIs, and involvement in alternative income generating activities. The adjusted odds ratios at 95% confidence interval computed during binary logistic regression analysis were used to determine the behaviour change predictor factors. Most FSWs (84%) had participated in AMREF's integrated intervention programme for at least one year and 59.1% had gone through behaviour change. The adjusted odds ratio showed that the FSWs with secondary education were 2.23 times likely to change behaviour, protestants were 4.61 times, those in sex work for >4 years were 2.36 times, FSWs with good HIV prevention knowledge were 4.37 times, and those engaged in alternative income generating activities were 2.30 times more likely to change their behaviour compared to respective counterparts. Behaviour change among FSWs was possible and is associated with the level of education, religious affiliation, number of years in sex work and one's level of HIV prevention knowledge. A re-orientation on the peer education programme to focus on HIV preventive measures beyond use of condoms is emphasized.

Mapping Causes and Implications of India’s Skewed Sex Ratio and Poverty problem using Fuzzy & Neutrosophic Relational Maps

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Gaurav

2016-08-01

Full Text Available Numerous studies by different researchers have confirmed that skewed sex ratio is a critical social problem in India. This enduring problem of gender imbalance is the collective result of factors like sex selective abortion, gender discrimination, son preference for the preservation of tribe, emergence of new technologies in medical field and many more factors. Another severe problem to be addressed in India is poverty. Many factors contribute to the perpetuation of poverty such as illiteracy, bad governance, under employment and various other reasons. Despite of India's accelerated growth rate, poverty in India is still prevalent.

A review of terrorism and its reduction of the gender ratio at birth after seasonal adjustment.

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Grech, Victor; Zammit, Dorota

2017-12-01

Males are born in excess of females, a ratio expressed as M/T (males:total births). The ratio exhibits seasonal variation. Furthermore, acute stressful events may result in a transient dip in male births due to excess foetal losses, reducing M/T. This study was carried out in order to identify significant M/T dips after adjusting for seasonality. Live births by gender and month were sought for acute stressful events. After seasonal correction (where appropriate), M/T dips were sought. Live births. M/T dips. This paper studied 112,226,306 live births. The following events showed dips ≤5th percentile 3-5months after these acute episodes: the Brooklyn Bridge protests, Katrina Hurricane for all 4 states and for each individual state (Alabama, Florida, Louisiana, Mississippi), the Battle in Seattle, the London bombings, The Madrid bombings (for Madrid and for Spain), the Breivik shooting, the Oklahoma City bombing and the Sandy Hook Elementary School shooting. The Virginia Polytechnic Institute and State University shooting the Fukushima Daiichi nuclear disaster also showed dips albeit slightly later. Seasonal adjustments should be taken into consideration in order to avoid Type 1 or 2 error pitfalls. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

Christopher C. Downs; Robert G. White; Bradley B. Shepard

1997-01-01

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...

Borderline personality disorder and regularly drinking alcohol before sex.

Science.gov (United States)

Thompson, Ronald G; Eaton, Nicholas R; Hu, Mei-Chen; Hasin, Deborah S

2017-07-01

Drinking alcohol before sex increases the likelihood of engaging in unprotected intercourse, having multiple sexual partners and becoming infected with sexually transmitted infections. Borderline personality disorder (BPD), a complex psychiatric disorder characterised by pervasive instability in emotional regulation, self-image, interpersonal relationships and impulse control, is associated with substance use disorders and sexual risk behaviours. However, no study has examined the relationship between BPD and drinking alcohol before sex in the USA. This study examined the association between BPD and regularly drinking before sex in a nationally representative adult sample. Participants were 17 491 sexually active drinkers from Wave 2 of the National Epidemiologic Survey on Alcohol and Related Conditions. Logistic regression models estimated effects of BPD diagnosis, specific borderline diagnostic criteria and BPD criterion count on the likelihood of regularly (mostly or always) drinking alcohol before sex, adjusted for controls. Borderline personality disorder diagnosis doubled the odds of regularly drinking before sex [adjusted odds ratio (AOR) = 2.26; confidence interval (CI) = 1.63, 3.14]. Of nine diagnostic criteria, impulsivity in areas that are self-damaging remained a significant predictor of regularly drinking before sex (AOR = 1.82; CI = 1.42, 2.35). The odds of regularly drinking before sex increased by 20% for each endorsed criterion (AOR = 1.20; CI = 1.14, 1.27) DISCUSSION AND CONCLUSIONS: This is the first study to examine the relationship between BPD and regularly drinking alcohol before sex in the USA. Substance misuse treatment should assess regularly drinking before sex, particularly among patients with BPD, and BPD treatment should assess risk at the intersection of impulsivity, sexual behaviour and substance use. [Thompson Jr RG, Eaton NR, Hu M-C, Hasin DS Borderline personality disorder and regularly drinking alcohol

Gender identity: a multidimensional analysis with implications for psychosocial adjustment.

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Egan, S K; Perry, D G

2001-07-01

This study examined the relations between components of gender identity and psychosocial adjustment. The aspects of gender identity assessed were (a) feelings of psychological compatibility with one's gender (i.e.. feeling one is a typical member of one's sex and feeling content with one's biological sex), (b) feelings of pressure from parents, peers, and self for conformity to gender stereotypes. and (c) the sentiment that one's own sex is superior to the other (intergroup bias). Adjustment was assessed in terms of self-esteem and peer acceptance. Participants were 182 children in Grades 4 through 8. Felt gender compatibility (when operationalized as either self-perceived gender typicality or feelings of contentment with one's biological sex) was positively related to adjustment, whereas felt pressure and intergroup bias were negatively associated with adjustment. The results provide new insights into the role of gender identity in children's well-being, help identify sources of confusion in previous work, and suggest directions for future inquiry.

Mode of action, origin and structure of the Paternal Sex Ratio chromosome in the parasitoid wasp Trichogramma kaykai

NARCIS (Netherlands)

Vugt, van J.J.F.A.

2005-01-01

Selfish genetic elements are defined as genetic elements that have a replication advantage relative to the rest of the genome. They are ubiquitous in nature and were extensively reported for almost all species studied so far. A special type of selfish genetic element, the sex ratio distorter, is

Female bias in the adult sex ratio of African annual fishes: interspecific differences, seasonal trends and environmental predictors

Czech Academy of Sciences Publication Activity Database

Reichard, Martin; Polačik, Matej; Blažek, Radim; Vrtílek, Milan

2014-01-01

Roč. 28, č. 6 (2014), s. 1105-1120 ISSN 0269-7653 R&D Projects: GA ČR(CZ) GAP506/11/0112 Institutional support: RVO:68081766 Keywords : Killifish * Tertiary sex ratio * Predator bias * Temporary savanna pools * Demographic consequences Subject RIV: EG - Zoology Impact factor: 2.517, year: 2014

DNA methylation of the gonadal aromatase (cyp19a promoter is involved in temperature-dependent sex ratio shifts in the European sea bass.

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Laia Navarro-Martín

2011-12-01

Full Text Available Sex ratio shifts in response to temperature are common in fish and reptiles. However, the mechanism linking temperature during early development and sex ratios has remained elusive. We show in the European sea bass (sb, a fish in which temperature effects on sex ratios are maximal before the gonads form, that juvenile males have double the DNA methylation levels of females in the promoter of gonadal aromatase (cyp19a, the enzyme that converts androgens into estrogens. Exposure to high temperature increased the cyp19a promoter methylation levels of females, indicating that induced-masculinization involves DNA methylation-mediated control of aromatase gene expression, with an observed inverse relationship between methylation levels and expression. Although different CpGs within the sb cyp19a promoter exhibited different sensitivity to temperature, we show that the increased methylation of the sb cyp19a promoter, which occurs in the gonads but not in the brain, is not a generalized effect of temperature. Importantly, these effects were also observed in sexually undifferentiated fish and were not altered by estrogen treatment. Thus, methylation of the sb cyp19a promoter is the cause of the lower expression of cyp19a in temperature-masculinized fish. In vitro, induced methylation of the sb cyp19a promoter suppressed the ability of SF-1 and Foxl2 to stimulate transcription. Finally, a CpG differentially methylated by temperature and adjacent to a Sox transcription factor binding site is conserved across species. Thus, DNA methylation of the aromatase promoter may be an essential component of the long-sought-after mechanism connecting environmental temperature and sex ratios in vertebrate species with temperature-dependent sex determination.

Project STYLE: a multisite RCT for HIV prevention among youths in mental health treatment.

Science.gov (United States)

Brown, Larry K; Hadley, Wendy; Donenberg, Geri R; DiClemente, Ralph J; Lescano, Celia; Lang, Delia M; Crosby, Richard; Barker, David; Oster, Danielle

2014-03-01

The study examined the efficacy of family-based and adolescent-only HIV prevention programs in decreasing HIV risk and improving parental monitoring and sexual communication among youths in mental health treatment. A randomized controlled trial (RCT) with 721 adolescents (ages 13-18 years) and their caregivers from mental health settings in three U.S. cities were randomly assigned to one of three theory-based, structured group interventions: family-based HIV prevention, adolescent-only HIV prevention, and adolescent-only health promotion. Interventions were delivered during an all-day workshop. Assessments were completed at baseline and three months postintervention. Compared with those in the health intervention, adolescents in the HIV prevention interventions reported fewer unsafe sex acts (adjusted rate ratio=.49, p=.01), greater condom use (adjusted relative change=59%, p=.01), and greater likelihood of avoiding sex (adjusted odds ratio=1.44, p=.05). They also showed improved HIV knowledge (pprevention interventions reduced sexual risk behavior over three months in a large, diverse sample of youths in mental health treatment and that the family-based intervention improved parental monitoring and communication with teens about sex. These interventions show promise.

Angiogenesis in symptomatic intracranial atherosclerosis: predominance of the inhibitor endostatin is related to a greater extent and risk of recurrence.

Science.gov (United States)

Arenillas, Juan F; Alvarez-Sabín, José; Montaner, Joan; Rosell, Anna; Molina, Carlos A; Rovira, Alex; Ribó, Marc; Sánchez, Esther; Quintana, Manuel

2005-01-01

Angiogenesis may be beneficial in chronic myocardial and limb ischemia, but its role in intracranial atherosclerosis remains unknown. We aimed to investigate the relationship between the pro-angiogenic vascular endothelial growth factor (VEGF) and the anti-angiogenic endostatin, and the extent and risk of recurrence of symptomatic intracranial atherosclerosis. Of a total of 94 consecutive patients with symptomatic intracranial stenoses, 40 fulfilled all inclusion criteria. Intracranial stenoses were confirmed by magnetic resonance angiography. Magnetic resonance imaging (MRI) including diffusion-weighted sequences was conducted. Plasmatic VEGF and endostatin were determined from blood samples obtained 3 months after stroke onset, and patients were followed-up thereafter. A total of 144 intracranial stenoses were confirmed (median number per patient=3). Endostatin/VEGF ratio gradually augmented with the increasing number of intracranial stenoses (r=0.35, P=0.02). Diabetes mellitus (OR, 6.04; CI, 1.1 to 32.2; P=0.03) and a higher endostatin/VEGF ratio (OR, 15.7; CI, 2.2 to 112.3; P=0.006) were independently associated with a greater extent of intracranial atherosclerosis. During a median follow-up of 13 months, 8 patients (20%) experienced a new cerebral ischemic event. A higher baseline endostatin concentration was an independent predictor of new events (hazard ratio, 7.24; CI, 1.6 to 33.8; P=0.011) in a Cox regression model after adjustment for age, sex, number of stenotic vessels, and risk factors. Patients with a higher endostatin level had a lower survival free of new events (P=0.01, log-rank test). A predominance of the inhibitor endostatin within the endogenous angiogenic response is associated with a greater extent and risk of recurrence of symptomatic intracranial atherosclerosis, suggesting that angiogenesis may be beneficial in this condition.

Sex differences in muscle morphology of the knee flexors and knee extensors.

Directory of Open Access Journals (Sweden)

Fearghal P Behan

Full Text Available Females experience higher risk of anterior cruciate ligament (ACL injuries; males experience higher risk of hamstring strain injuries. Differences in injury may be partially due to sex differences in knee flexor (KF to knee extensor (KE muscle size ratio and the proportional size of constituent muscles.To compare the absolute and proportional size, and mass distribution, of individual KE and KF muscles, as well as overall size and balance (size ratio of these muscle groups between the sexes.T1-weighted axial plane MR images (1.5T of healthy untrained young males and females (32 vs 34 were acquired to determine thigh muscle anatomical cross-sectional area (ACSA. Maximal ACSA (ACSAmax of constituent muscles, summated for KF and KE muscle groups, and the KF:KE ratio were calculated.Females had 25.3% smaller KE ACSAmax (70.9±12.1 vs 93.6±10.3 cm2; P<0.001 and 29.6% smaller KF ACSAmax than males (38.8±7.3cm2 vs 55.1±7.3cm2; P<0.001. Consequently, females had lower KF:KE ACSA ratio (P = 0.031. There were sex differences in the proportional size of 2/4 KE and 5/6 KF. In females, vastus lateralis (VL, biceps femoris long-head (BFlh and semimembranosus (SM were a greater proportion and sartorius (SA, gracilis (GR and biceps femoris short-head (BFsh a smaller proportion of their respective muscle groups compared to males (All P<0.05.Sex differences in KF:KE ACSAmax ratio may contribute to increased risk of ACL injury in females. Sex discrepancies in absolute and proportional size of SA, GR, VL and BFlh may contribute further anatomical explanations for sex differences in injury incidence.

Transcriptome profiling of Nasonia vitripennis testis reveals novel transcripts expressed from the selfish B chromosome, paternal sex ratio.

Science.gov (United States)

Akbari, Omar S; Antoshechkin, Igor; Hay, Bruce A; Ferree, Patrick M

2013-09-04

A widespread phenomenon in nature is sex ratio distortion of arthropod populations caused by microbial and genetic parasites. Currently little is known about how these agents alter host developmental processes to favor one sex or the other. The paternal sex ratio (PSR) chromosome is a nonessential, paternally transmitted centric fragment that segregates in natural populations of the jewel wasp, Nasonia vitripennis. To persist, PSR is thought to modify the hereditary material of the developing sperm, with the result that all nuclear DNA other than the PSR chromosome is destroyed shortly after fertilization. This results in the conversion of a fertilized embryo--normally a female--into a male, thereby insuring transmission of the "selfish" PSR chromosome, and simultaneously leading to wasp populations that are male-biased. To begin to understand this system at the mechanistic level, we carried out transcriptional profiling of testis from WT and PSR-carrying males. We identified a number of transcripts that are differentially expressed between these conditions. We also discovered nine transcripts that are uniquely expressed from the PSR chromosome. Four of these PSR-specific transcripts encode putative proteins, whereas the others have very short open reading frames and no homology to known proteins, suggesting that they are long noncoding RNAs. We propose several different models for how these transcripts could facilitate PSR-dependent effects. Our analyses also revealed 15.71 MB of novel transcribed regions in the N. vitripennis genome, thus increasing the current annotation of total transcribed regions by 53.4%. Finally, we detected expression of multiple meiosis-related genes in the wasp testis, despite the lack of conventional meiosis in the male sex.

Pregravid hypertension may have different secondary sex ratio effects in different races in the United States.

Science.gov (United States)

Grech, Victor

2017-12-01

Males are born in excess of females and the ratio is expressed as M/F (male/female births=secondary sex ratio, also known as secondary sex ratio). This is expected to approximate 1.048. Racial M/F disparities are known. A recent study in China showed that pregravid systolic hypertension is higher in women who delivered a boy than in those who had a girl. This study was carried out in order to identify the effect of pregravid hypertension in the United States on M/F by race. Monthly male and female live births by race for the entire US along with the presence/absence of hypertension were obtained from the website of the Centers for Disease Control and Prevention for 2007-2015 for the four racial groups: American Indian or Alaska Native, Asian or Pacific Islander, Black or African American and White. This study analysed 36,364,253 live births. For White births, mothers who had chronic hypertension were likelier to have male than female offspring when compared to non-hypertensives (p=0.003). Conversely, Black or African American mothers who had hypertension were less likely to have male than female offspring when compared to non-hypertensives (p=0.022). There were F differences for/F differences for the presence or absence of hypertension for the other two races or for the total. It is possible that hypothesised innate interracial periconceptual hormonal differences may modulate M/F responses to hypertension in different races. Copyright © 2017 Elsevier B.V. All rights reserved.

Genetically significant dose and sex ratio of the offsprings of patient treated with 131I for hyperthyroidism

International Nuclear Information System (INIS)

Takeshita, Akihisa

1975-01-01

The gonadal doses following the 131 I treatment of 6 male and 14 female patients with hyperthyroidism were calculated by the method of MIRD, measuring daily radioactivity in the thyroid gland and circulating blood. The testicular dose was 0.52 +- 0.256 rads and the ovarian dose was 0.632 +- 0.488 rads per mCi. In 1965, the genetically significant dose from 131 I treatment of 925 patients with hyperthyroidism was estimated to be 0.0136 mrads/person/year. The genetically significant dose would amount to 0.0613 mrads/person/year, assuming that the total amount of 131 I supplied for treatment in 1965 was administered to treat the hyperthyroid patients with an age-and sex distribution similar to that of the above mentioned group of patients. Sex ratios of the offspring of male and female patients treated with 131 I from 1953 to 1966 were compared with those of offspring born to male and female patients before the treatment. The proportion of males was higher among the offspring of male patients after 131 I treatment than among the offspring of the controls, but the difference was not statistically significant. The sex ratio of the offspring of female patients was not different from that of controls. The mean age of the parents at the times of their children's birth after 131 I treatment was 2.6 - 6.0 year older in male patients and 2.8 - 2.9 year older in female patients than that of controls. (J.P.N.)

Risky business: Is there an association between casual sex and mental health among emerging adults?

Science.gov (United States)

Bersamin, Melina M; Zamboanga, Byron L; Schwartz, Seth J; Donnellan, M Brent; Hudson, Monika; Weisskirch, Robert S; Kim, Su Yeong; Agocha, V Bede; Whitbourne, Susan Krauss; Caraway, S Jean

2014-01-01

A multiethnic sample of single, heterosexual, emerging-adult college students (N = 3,907) ages 18 to 25, from 30 institutions across the United States, participated in a study about identity, culture, psychological well-being, and risky behaviors. Given ongoing debates about the connection between casual sex and psychological adjustment, in the current study we assessed the cross-sectional association of participation in casual sex with psychological well-being and distress. A greater proportion of men (18.6%) compared to women (7.4%) reported having had casual sex in the month prior to assessment. Structural equation modeling indicated that casual sex was negatively associated with well-being (ß = .20, p < .001) and positively associated with psychological distress (ß = .16, p < .001). Gender did not moderate these associations. For emerging-adult college students, engaging in casual sex may elevate risk for negative psychological outcomes.

Levels and correlates of internalized homophobia among men who have sex with men in Pretoria, South Africa.

Science.gov (United States)

Vu, Lung; Tun, Waimar; Sheehy, Meredith; Nel, Dawie

2012-04-01

This study examines levels and correlates of internalized homophobia among men who have sex with men (MSM) in Pretoria, South Africa. Using respondent-driven sampling, we recruited 324 MSM from February to August 2009. Results were adjusted using RDSAT analysis to yield population-based estimates. High levels of internalized homophobia exist among South African MSM: 10-15% reported "often/very often" and over 20% reported "sometimes" having feelings of internalized homophobia. A greater level of internalized homophobia was significantly associated with a lower level of education [Adjusted Odds Ratio = 2.2; 95% CI = 1.1-4.9], a higher level of HIV misinformation [AOR = 2.7; 95% CI: 1.3-5.3], bisexual identity (vs. homosexual) [AOR = 5.5; 95% CI: 2.5-12.0], and HIV-related conspiracy beliefs [AOR = 2.4; 95% CI: 1.02-5.8]. These findings contribute valuable information to our understanding of internalized homophobia in South Africa, highlighting the need to empower the gay community, promote self-acceptance of homosexual identity, and address conspiracy beliefs among MSM to reduce internalized homophobia and increase access to HIV prevention interventions.

Long-term follow-up of transsexual persons undergoing sex reassignment surgery: cohort study in Sweden.

Directory of Open Access Journals (Sweden)

Cecilia Dhejne

Full Text Available CONTEXT: The treatment for transsexualism is sex reassignment, including hormonal treatment and surgery aimed at making the person's body as congruent with the opposite sex as possible. There is a dearth of long term, follow-up studies after sex reassignment. OBJECTIVE: To estimate mortality, morbidity, and criminal rate after surgical sex reassignment of transsexual persons. DESIGN: A population-based matched cohort study. SETTING: Sweden, 1973-2003. PARTICIPANTS: All 324 sex-reassigned persons (191 male-to-females, 133 female-to-males in Sweden, 1973-2003. Random population controls (10:1 were matched by birth year and birth sex or reassigned (final sex, respectively. MAIN OUTCOME MEASURES: Hazard ratios (HR with 95% confidence intervals (CI for mortality and psychiatric morbidity were obtained with Cox regression models, which were adjusted for immigrant status and psychiatric morbidity prior to sex reassignment (adjusted HR [aHR]. RESULTS: The overall mortality for sex-reassigned persons was higher during follow-up (aHR 2.8; 95% CI 1.8-4.3 than for controls of the same birth sex, particularly death from suicide (aHR 19.1; 95% CI 5.8-62.9. Sex-reassigned persons also had an increased risk for suicide attempts (aHR 4.9; 95% CI 2.9-8.5 and psychiatric inpatient care (aHR 2.8; 95% CI 2.0-3.9. Comparisons with controls matched on reassigned sex yielded similar results. Female-to-males, but not male-to-females, had a higher risk for criminal convictions than their respective birth sex controls. CONCLUSIONS: Persons with transsexualism, after sex reassignment, have considerably higher risks for mortality, suicidal behaviour, and psychiatric morbidity than the general population. Our findings suggest that sex reassignment, although alleviating gender dysphoria, may not suffice as treatment for transsexualism, and should inspire improved psychiatric and somatic care after sex reassignment for this patient group.

Are environmental factors responsible for geographic variation in the sex ratio of the Greenlandic seed-bug Nysius groenlandicus?

DEFF Research Database (Denmark)

Bøcher, Jens Jensenius; Nachman, Gøsta Støger

2010-01-01

Until recently nothing indicated an unequal sex ratio in the widespread Greenland seed-bug Nysius groenlandicus (Zetterstedt) (Heteroptera: Lygaeidae). However, recently populations more or less devoid of males were discovered in high arctic Northeast Greenland. This initiated an inspection of th...

The Influence of Age and Sex on Genetic Associations with Adult Body Size and Shape

DEFF Research Database (Denmark)

Winkler, Thomas W; Justice, Anne E; Graff, Mariaelisa

2015-01-01

Genome-wide association studies (GWAS) have identified more than 100 genetic variants contributing to BMI, a measure of body size, or waist-to-hip ratio (adjusted for BMI, WHRadjBMI), a measure of body shape. Body size and shape change as people grow older and these changes differ substantially...... (G x AGE), sex-specific effects (G x SEX) or age-specific effects that differed between men and women (G x AGE x SEX). For BMI, we identified 15 loci (11 previously established for main effects, four novel) that showed significant (FDR... effects on WHRadjBMI. These results may provide further insights into the biology that underlies weight change with age or the sexually dimorphism of body shape....

Sex differences in physical and mental functioning of Japanese civil servants: explanations from work and family characteristics.

Science.gov (United States)

Sekine, Michikazu; Chandola, Tarani; Martikainen, Pekka; Marmot, Michael; Kagamimori, Sadanobu

2010-12-01

Poor physical and mental functioning are more common among women than men and those with disadvantaged work and family characteristics. This study aims to clarify whether sex differences in health functioning can be explained by sex differences in work and family characteristics. The subjects were 3787 civil servants (2525 men and 1262 women), aged 20-65, working in a local government on the west coast of Japan. A questionnaire survey was conducted in January 2003. Low employment grade, high demands, long work hours, shift work, being unmarried, having no young children, high family-to-work conflict and high work-to-family conflict were more common among women than men and were independently associated with poor physical and mental functioning. The age-adjusted odds ratios (ORs) of women for poor health functioning were 1.80 for poor physical functioning and 1.77 for poor mental functioning. When adjusted for employment grade and work characteristics (control, demand, support, work hours, and shift work), the sex differences in health functioning attenuated. When adjusted for family characteristics (family structure and work-family conflicts), the sex differences in health functioning further attenuated and were no longer statistically significant. Sex differences in family characteristics contributed more to sex difference in mental functioning than sex differences in work characteristics. Japan belongs to conservative welfare regimes. In such countries, men are able to concentrate on their work with relative freedom from their family tasks and responsibilities, whereas women feel difficulties in maintaining their work-life balances. Such sex differences in work- and family-related stresses may contribute to sex difference in health. Longitudinal research is necessary to clarify the causal nature of these associations. Copyright © 2010 Elsevier Ltd. All rights reserved.

Parental behaviour is unrelated to experimentally manipulated great tit brood sex ratio

NARCIS (Netherlands)

Lessells, C.M.; Oddie, K.R.; Mateman, A.C.

1998-01-01

Parental investment may be biased with respect to parental sex or offspring sex or there may be an interaction between parental and offspring sex. We investigated whether any of these types of bias occurred in great tits, Parus major. By sexing chicks using random amplified polymorphic DNA (RAPD)

Sex differences in college students' free drawings and their relationship to 2D:4D ratio and recalled childhood play behavior.

Science.gov (United States)

Rothkopf, Ian; Turgeon, Sarah M

2014-02-01

In a prior study, we observed that female-typical characteristics in elementary school girls' drawings were correlated with a feminized digit ratio (2D:4D), a marker for prenatal androgen exposure. However, this observation was limited to older girls, suggesting that social factors mediate the relationship between 2D:4D and drawing. To examine the hypothesis that the influence of prenatal androgen on girls' drawing is mediated by an effect of early androgens on sex-typical behavior, we examined 2D:4D, free drawings, and scores on the Recalled Childhood Gender Identity (RCGI) Questionnaire in a population of college students. Characteristics of participants' free drawings were assessed and those that showed sex differences were compared with 2D:4D and RCGI scores. Men had smaller 2D:4D ratios than women, used fewer total colors, used fewer pinks, purples, and blues, and had higher gender-typical scores on the RCGI. Women's drawings were more likely to contain flowers and animals and men's drawings were more likely to represent sports. Within-sex RCGI and 2D:4D scores were not significantly correlated. Significant within-sex relationships between 2D:4D and RCGI and drawing behavior were observed but the effects appeared to be independent; the hypothesis that gender-typical childhood behavior mediates the effect of prenatal androgen on drawing characteristics was not supported.

Should the Sexes Be Separated for Secondary Education--Comparisons of Single-Sex and Co-Educational Schools?

Science.gov (United States)

Robinson, Pamela; Smithers, Alan

1999-01-01

English researchers compared the academic and social benefits of single sex and coeducational schools, examining test scores and interviewing 100 college students (balanced for sex and type of school) about their experiences and their ease of adjustment to higher education. Results indicated that segregating the sexes did not increase…

Psychosocial Adjustment to Sex Reassignment Surgery: A Qualitative Examination and Personal Experiences of Six Transsexual Persons in Croatia

Science.gov (United States)

Jokić-Begić, Nataša; Jurin, Tanja

2014-01-01

In Croatia, transgender individuals face numerous social and medical obstacles throughout the process of transition. The aim of this study was to depict the factors contributing to the psychosocial adjustment of six transsexual individuals living in Croatia following sex reassignment surgery (SRS). A combination of quantitative and qualitative self-report methods was used. Due to the specificity of the sample, the data were collected online. Standardized questionnaires were used to assess mental health and quality of life alongside a series of open-ended questions divided into 4 themes: the decision-making process regarding SRS; social and medical support during the SRS process; experience of discrimination and stigmatizing behaviors; psychosocial adjustment after SRS. Despite the unfavorable circumstances in Croatian society, participants demonstrated stable mental, social, and professional functioning, as well as a relative resilience to minority stress. Results also reveal the role of pretransition factors such as high socioeconomic status, good premorbid functioning, and high motivation for SRS in successful psychosocial adjustment. During and after transition, participants reported experiencing good social support and satisfaction with the surgical treatment and outcomes. Any difficulties reported by participants are related to either sexual relationships or internalized transphobia. The results also demonstrate the potentially protective role that a lengthier process of transition plays in countries such as Croatia. PMID:24790589

Sex differences in the prevalence, symptoms, and associated features of migraine, probable migraine and other severe headache: results of the American Migraine Prevalence and Prevention (AMPP) Study.

Science.gov (United States)

Buse, Dawn C; Loder, Elizabeth W; Gorman, Jennifer A; Stewart, Walter F; Reed, Michael L; Fanning, Kristina M; Serrano, Daniel; Lipton, Richard B

2013-09-01

the prevalence of migraine and PM, but not for other severe headache. Adjusted female to male prevalence ratios ranged from 1.48 to 3.25 across the lifetime for migraine and from 1.22 to 1.53 for PM. Sex differences were also observed in associated symptomology, aura, headache-related disability, healthcare resource utilization, and diagnosis for migraine and PM. Despite higher rates of migraine diagnosis by a healthcare professional, females with migraine were less likely than males to be using preventive pharmacologic treatment for headache. In this large, US population sample, both migraine and PM were more common among females, but a sex difference was not observed in the prevalence of other severe headache. The sex difference in migraine and PM held true across age and for most other sociodemographic variables with the exception of race for PM. Females with migraine and PM had higher rates of most migraine symptoms, aura, greater associated impairment, and higher healthcare resource utilization than males. Corresponding sex differences were not observed among individuals with other severe headache on the majority of these comparisons. Results suggest that PM is part of the migraine spectrum whereas other severe headache types are not. Results also substantiate existing literature on sex differences in primary headaches and extend results to additional headache types and related factors. © 2013 American Headache Society.

Sexual satisfaction, sexual compatibility, and relationship adjustment in couples: the role of sexual behaviors, orgasm, and men's discernment of women's intercourse orgasm.

Science.gov (United States)

Klapilová, Kateřina; Brody, Stuart; Krejčová, Lucie; Husárová, Barbara; Binter, Jakub

2015-03-01

Research indicated that (i) vaginal orgasm consistency is associated with indices of psychological, intimate relationship, and physiological functioning, and (ii) masturbation is adversely associated with some such measures. The aim of this study was to examine the association of various dyadic and masturbation behavior frequencies and percentage of female orgasms during these activities with: (i) measures of dyadic adjustment; (ii) sexual satisfaction; and (iii) compatibility perceived by both partners. In a sample of 85 Czech long-term couples (aged 20-40; mean relationship length 5.4 years), both partners provided details of recent sexual behaviors and completed sexual satisfaction, Spanier dyadic adjustment, and Hurlbert sexual compatibility measures. Multiple regression analyses were used. The association of sexual behaviors with dyadic adjustment, sexual compatibility, and satisfaction was analyzed. In multivariate analyses, women's dyadic adjustment is independently predicted by greater vaginal orgasm consistency and lower frequency of women's masturbation. For both sexes, sexual compatibility was independently predicted by higher frequency of penile-vaginal intercourse and greater vaginal orgasm consistency. Women's sexual satisfaction score was significantly predicted by greater vaginal orgasm consistency, frequency of partner genital stimulation, and negatively with masturbation. Men's sexual satisfaction score was significantly predicted by greater intercourse frequency and any vaginal orgasm of their female partners. Concordance of partner vaginal orgasm consistency estimates was associated with greater dyadic adjustment. The findings suggest that specifically penile-vaginal intercourse frequency and vaginal orgasm consistency are associated with indices of greater intimate relationship adjustment, satisfaction, and compatibility of both partners, and that women's masturbation is independently inversely associated with measures of dyadic and personal

Social-environmental factors and protective sexual behavior among sex workers: the Encontros intervention in Brazil.

Science.gov (United States)

Lippman, Sheri A; Donini, Angela; Díaz, Juan; Chinaglia, Magda; Reingold, Arthur; Kerrigan, Deanna

2010-04-01

We sought to determine the association of social-environmental factors with condom use and sexually transmitted infections (STIs) among 420 sex workers participating in an STI/HIV prevention study in Corumbá, Brazil, to inform future intervention efforts. Participants provided urine samples for polymerase chain reaction testing of chlamydia and gonorrhea and responded to multi-item scales addressing perceived social cohesion, participation in networks, and access to and management of resources. We conducted multivariate log-linear and negative binomial regression analyses of these data. Increased social cohesion was inversely associated with number of unprotected sex acts in the preceding week among women (adjusted incidence rate ratio [IRR] = 0.80; P < .01), and there was a marginal association among men (adjusted IRR = 0.41; P = .08). Women's increased participation in social networks was associated with a decrease in frequency of unprotected sex acts (adjusted IRR = 0.83; P = .04), as was men's access to and management of social and material resources (IRR = 0.15; P = .01). Social-environmental factors were not associated with STIs. The social context within which populations negotiate sexual behaviors is associated with condom use. Future efforts to prevent STI/HIV should incorporate strategies to modify the social environment.

Effects of Age and Sex on Hospital Readmission in Traumatic Brain Injury.

Science.gov (United States)

Li, Chih-Ying; Karmarkar, Amol; Adhikari, Deepak; Ottenbacher, Kenneth; Kuo, Yong-Fang

2018-01-04

To investigate the effects of age and sex on 30-, 60-, and 90-day hospital readmission after acute hospital discharge for individuals with traumatic brain injury (TBI). Retrospective cohort study. Acute hospitals and postacute discharge settings. Individuals (N=52,877) with Diagnosis Related Group codes of TBI, who were divided into 4 age groups: 18 to 40, 41 to 65, 66 to 75, and ≥76 years. Not applicable. All-cause hospital readmission. Sex differences in 30-, 60-, and 90-day hospital readmission were found among all age groups (Preadmission were in the 2 oldest groups (66-75 and ≥76y). For both sexes, the oldest group (≥76y) had the highest adjusted 90-day readmission risk (eg, 90-d readmission: odds ratio, 2.32 [95% confidence interval, 2.01-2.69] for men; odds ratio, 1.96 [95% confidence interval, 1.59-2.43] for women). Among those readmitted within 90 days, the youngest group (18-40y) had the highest cumulative readmission percentage (35% for both sexes) within the first week of hospital discharge. Age and sex were significantly associated with hospital readmission during the first 90 days postdischarge in our TBI sample. Specifically, those aged 66 to 75 or ≥76 years had the highest readmission risk over 90 days for both sexes. The findings suggest that clinicians should consider age and sex in discharge planning and for the entire episode of care for the population with TBI. Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Where is the bride? Progressively declining sex ratio in India: an alarming signal for imbalanced society

OpenAIRE

Nirmala Sharma; Kana Ram; Anand Sharma; Shashi Sharma

2014-01-01

Female feticide is an extreme form of violence against women, the most active part is being played by the women themselves just for the mere want of a boy, mothers dont feel bad in strangulating their own daughters in their wombs. From decades of sex determination and female feticide is creating a statistical imbalance regarding the commonly expected and lsquo;male: female' birth ratio in India. This offense have been spreaded to the states in India like Punjab, Haryana, Delhi, Gujarat and R...

Sex, age, pubertal development and use of oral contraceptives in relation to serum concentrations of DHEA, DHEAS, 17α-hydroxyprogesterone, Δ4-androstenedione, testosterone and their ratios in children, adolescents and young adults.

Science.gov (United States)

Søeborg, Tue; Frederiksen, Hanne; Mouritsen, Annette; Johannsen, Trine Holm; Main, Katharina Maria; Jørgensen, Niels; Petersen, Jørgen Holm; Andersson, Anna-Maria; Juul, Anders

2014-11-01

The influence of sex, age, pubertal development and oral contraceptives on dehydroepiandrosterone (DHEA), DHEA sulfate (DHEAS), 17α-hydroxyprogesterone (17-OHP), Δ4-androstenedione (Adione), testosterone (T), calculated free testosterone (fT), free androgen index (FAI) and selected ratios in 1798 serum samples from healthy children, adolescents and young adults was evaluated. Samples were analyzed by Turboflow-LC-MS/MS. Sex hormone-binding globulin was analyzed by immunoassay. All steroid metabolite concentrations were positively associated with age and pubertal development in both sexes and generally higher in males than in females except for Adione. The pubertal rise in T in males was more pronounced compared to females, reflecting contribution from the testes. Ratios between steroid metabolites varied and depended on sex and age. All ratios were lower during infancy compared to later in life. Use of oral contraceptives significantly lowered serum concentrations of all steroid metabolites, fT, FAI, the 17-OHP/Adione, the Adione/T and the DHEA/Adione ratios, but not the DHEA/DHEAS ratio. We provide reference ranges for DHEA, DHEAS, 17-OHP, Adione, T, fT, FAI and selected ratios in relation to sex, age and pubertal development. Use of oral contraceptives strongly influences adrenal steroidogenesis and should be considered when diagnosing and monitoring treatment of patients with disorders of sex development. Copyright © 2014 Elsevier B.V. All rights reserved.

Unmet need for contraception among sex workers in Madagascar☆,☆☆

Science.gov (United States)

Khan, Maria R.; Turner, Abigail Norris; Pettifor, Audrey; Van Damme, Kathleen; Rabenja, Ny Lovaniaina; Ravelomanana, Noro; Swezey, Teresa; Williams, D’Nyce; Jamieson, Denise; Behets, Frieda

2018-01-01

Background The study was conducted to investigate past and future pregnancy preferences and contraceptive need among Malagasy sex workers. Study Design We analyzed data on pregnancy and contraceptive use collected during the baseline visit of a randomized, prospective formative trial which assessed diaphragm and microbicide acceptability among sex workers. To be eligible, women could not be pregnant or planning pregnancy for the next 2 months. Results Women (N=192) from four cities (Antananarivo, Antsiranana, Mahajanga and Toamasina) reported a median of 10 sex acts per week. Fifty-two percent reported a prior unwanted pregnancy, 45% at least one induced abortion and 86% that preventing future pregnancy was moderately to very important. During the last sex act, 24% used a hormonal method, 36% used a male condom, 2% used a traditional method and 38% used no method. Nearly 30% of participants reported that pregnancy prevention was moderately or very important but used no contraception at last sex; these women were categorized as having “unmet need” for contraception. In multivariable binomial regression analyses, factors associated with unmet need included low knowledge of contraceptive effectiveness [age- and site-adjusted prevalence ratio (PR): 2.1; 95% confidence interval (CI): 1.4–3.0] and low self-efficacy to negotiate condom use (age- and site-adjusted PR: 2.0; 95% CI: 1.4–3.0). Conclusions Among these women, prior unwanted pregnancy and induced abortion were common and preventing future pregnancy was important, yet gaps in contraceptive use were substantial. Contraceptive knowledge and self-efficacy should be improved to promote contraceptive use by sex workers. PMID:19185677

Impact of consanguineous marriages and degrees of inbreeding on fertility, child mortality, secondary sex ratio, selection intensity, and genetic load: a cross-sectional study from Northern India.

Science.gov (United States)

Fareed, Mohd; Kaisar Ahmad, Mir; Azeem Anwar, Malik; Afzal, Mohammad

2017-01-01

The aim of our study was to understand the relationship between consanguineous marriages and reproductive outcomes. A total of 999 families were recruited from five Muslim populations of Jammu region. Family pedigrees were drawn to access the family history and inbreeding status in terms of coefficient of inbreeding (F). Fertility, mortality, secondary sex ratio, selection intensity, and lethal equivalents were measured using standard methods. The significant differences for gross fertility was found to be higher among inbred groups as compared to the unrelated families (P consanguineous families of all populations in comparison with the non-consanguineous family groups. Moreover, the prenatal and postnatal child mortality rates (i.e., U5MR and U18MR) have presented a persuasive increase with an upsurge in the homozygosity level. The mortality rate was found to be maximum among families with the highest value of coefficient of inbreeding (F). The selection intensity (SI) also showed inflations among families with respect to their increasing inbreeding coefficients. The greater values of lethal equivalents per gamete (LEs/gamete) were observed for autosomal inheritance in comparison with sex-linked inheritance. Our conclusive assessment brings out the deleterious consequence of consanguineous marriages on reproductive outcomes.

Associations of sexually transmitted infections with condom problems among young men who have sex with men.

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Mustanski, Brian; Ryan, Daniel T; Garofalo, Robert

2014-07-01

Young men who have sex with men (YMSM) are disproportionately infected with sexually transmitted infections (STIs). Condom use is the most widely available means of preventing the transmission of STIs, but effectiveness depends on correct use. Condom errors such as using an oil-based lubricant have been associated with condom failures such as breakage. Little research has been done on the impact of condom problems on the likelihood of contracting an STI. Data came from Crew 450, a longitudinal study of HIV risk among YMSM (N = 450). All self-report data were collected using computer-assisted self-interview technology, and clinical testing was done for gonorrhea, chlamydia, and HIV. Nearly all participants made at least 1 error, with high rates of using oil-based lubricant and incomplete use. No differences were found in rates of condom problems during anal sex with a man versus vaginal sex with a woman. Black YMSM reported significantly higher use of oil-based lubricants than white and Hispanic YMSM, an error significantly associated with HIV status (adjusted odds ratio, 2.60; 95% confidence interval, 1.04-6.51). Participants who reported a condom failure were significantly more likely to have an STI (adjusted odds ratio, 3.27; 95% confidence interval, 1.31-8.12). Young men who have sex with men report high rates of condom problems, and condom failures were significantly associated with STIs after controlling for unprotected sex. Educational programs are needed to enhance correct condom use among YMSM. Further research is needed on the role of oil-based lubricants in explaining racial disparities in STIs and HIV.

Sex ratio, poverty, and concurrent partnerships among men and women in the United States: a multilevel analysis.

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Adimora, Adaora A; Schoenbach, Victor J; Taylor, Eboni M; Khan, Maria R; Schwartz, Robert J; Miller, William C

2013-11-01

Social and economic contextual factors may promote concurrent sexual partnerships, which can accelerate population HIV transmission and are more common among African Americans than U.S. Whites. We investigated the relationship between contextual factors and concurrency. We analyzed past 12-month concurrency prevalence in the 2002 National Survey of Family Growth and its contextual database in relation to county sex ratio (among respondent's racial and ethnic group), percentage in poverty (among respondent's racial and ethnic group), and violent crime rate. Analyses examined counties with balanced (0.95-1.05 males/female) or low (poverty (OR, 1.18; 95% CI, 0.98-1.42 per 10 percentage-point increase), and higher crime rates (OR, 1.04; 95% CI, 1.00-1.09 per 1000 population/year). Notably, 99.5% of Whites and 93.7% of Hispanics, but only 7.85% of Blacks, lived in balanced sex ratio counties; about 5% of Whites, half of Hispanics, and three-fourths of Blacks resided in counties with >20% same-race poverty. The dramatic Black-White differences in contextual factors in the United States and their association with sexual concurrency could contribute to the nation's profound racial disparities in HIV infection. Copyright © 2013 Elsevier Inc. All rights reserved.

Impact and determinants of sex preference in Nepal.

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Leone, Tiziana; Matthews, Zoë; Dalla Zuanna, Gianpiero

2003-06-01

Gender discrimination and son preference are key demographic features of South Asia and are well documented for India. However, gender bias and sex preference in Nepal have received little attention. 1996 Nepal Demographic and Health Survey data on ever-married women aged 15-49 who did not desire any more children were used to investigate levels of gender bias and sex preference. The level of contraceptive use and the total fertility rate in the absence of sex preference were estimated, and logistic regression was performed to analyze the association between socioeconomic and demographic variables and stopping childbearing after the birth of a son. Commonly used indicators of gender bias, such as sex ratio at birth and sex-specific immunization rates, do not suggest a high level of gender discrimination in Nepal. However, sex preference decreases contraceptive use by 24% and increases the total fertility rate by more than 6%. Women's contraceptive use, exposure to the media, parity, last birth interval, educational level and religion are linked to stopping childbearing after the birth of a boy, as is the ethnic makeup of the local area. The level of sex preference in Nepal is substantial. Sex preference is an important barrier to the increase of contraceptive use and decline of fertility in the country; its impact will be greater as desired family size declines.