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Sample records for sex ratio patterns

  1. Sex ratios

    OpenAIRE

    West, Stuart A; Reece, S E; Sheldon, Ben C

    2002-01-01

    Sex ratio theory attempts to explain variation at all levels (species, population, individual, brood) in the proportion of offspring that are male (the sex ratio). In many cases this work has been extremely successful, providing qualitative and even quantitative explanations of sex ratio variation. However, this is not always the situation, and one of the greatest remaining problems is explaining broad taxonomic patterns. Specifically, why do different organisms show so ...

  2. 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.

  3. 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...

  4. 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.

  5. 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.

  6. 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.

  7. Sex Ratio Elasticity Influences the Selection of Sex Ratio Strategy

    Science.gov (United States)

    Wang, Yaqiang; Wang, Ruiwu; Li, Yaotang; (Sam) Ma, Zhanshan

    2016-12-01

    There are three sex ratio strategies (SRS) in nature—male-biased sex ratio, female-biased sex ratio and, equal sex ratio. It was R. A. Fisher who first explained why most species in nature display a sex ratio of ½. Consequent SRS theories such as Hamilton’s local mate competition (LMC) and Clark’s local resource competition (LRC) separately explained the observed deviations from the seemingly universal 1:1 ratio. However, to the best of our knowledge, there is not yet a unified theory that accounts for the mechanisms of the three SRS. Here, we introduce the price elasticity theory in economics to define sex ratio elasticity (SRE), and present an analytical model that derives three SRSs based on the following assumption: simultaneously existing competitions for both resources A and resources B influence the level of SRE in both sexes differently. Consequently, it is the difference (between two sexes) in the level of their sex ratio elasticity that leads to three different SRS. Our analytical results demonstrate that the elasticity-based model not only reveals a highly plausible mechanism that explains the evolution of SRS in nature, but also offers a novel framework for unifying two major classical theories (i.e., LMC & LRC) in the field of SRS research.

  8. The evolution of sex ratios and sex-determining systems

    NARCIS (Netherlands)

    Uller, Tobias; Pen, Ido; Wapstra, Erik; Beukeboom, Leo W.; Komdeur, Jan

    Sex determination is a fundamental process governed by diverse mechanisms. Sex ratio selection is commonly implicated in the evolution of sex-determining systems, although formal models are rare. Here, we argue that, although sex ratio selection can induce shifts in sex determination, genomic

  9. 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

  10. A father effect explains sex-ratio bias.

    Science.gov (United States)

    Malo, Aurelio F; Martinez-Pastor, Felipe; Garcia-Gonzalez, Francisco; Garde, Julián; Ballou, Jonathan D; Lacy, Robert C

    2017-08-30

    Sex ratio allocation has important fitness consequences, and theory predicts that parents should adjust offspring sex ratio in cases where the fitness returns of producing male and female offspring vary. The ability of fathers to bias offspring sex ratios has traditionally been dismissed given the expectation of an equal proportion of X- and Y-chromosome-bearing sperm (CBS) in ejaculates due to segregation of sex chromosomes at meiosis. This expectation has been recently refuted. Here we used Peromyscus leucopus to demonstrate that sex ratio is explained by an exclusive effect of the father, and suggest a likely mechanism by which male-driven sex-ratio bias is attained. We identified a male sperm morphological marker that is associated with the mechanism leading to sex ratio bias; differences among males in the sperm nucleus area (a proxy for the sex chromosome that the sperm contains) explain 22% variation in litter sex ratio. We further show the role played by the sperm nucleus area as a mediator in the relationship between individual genetic variation and sex-ratio bias. Fathers with high levels of genetic variation had ejaculates with a higher proportion of sperm with small nuclei area. This, in turn, led to siring a higher proportion of sons (25% increase in sons per 0.1 decrease in the inbreeding coefficient). Our results reveal a plausible mechanism underlying unexplored male-driven sex-ratio biases. We also discuss why this pattern of paternal bias can be adaptive. This research puts to rest the idea that father contribution to sex ratio variation should be disregarded in vertebrates, and will stimulate research on evolutionary constraints to sex ratios-for example, whether fathers and mothers have divergent, coinciding, or neutral sex allocation interests. Finally, these results offer a potential explanation for those intriguing cases in which there are sex ratio biases, such as in humans. © 2017 The Author(s).

  11. 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.

  12. 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

  13. 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 ...

  14. 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

  15. Determining sex ratios of turtle hatchlings

    Data.gov (United States)

    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...

  16. 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

  17. 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

  18. Mother's occupation and sex ratio at birth

    Directory of Open Access Journals (Sweden)

    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

  19. 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

  20. Sex ratios at birth after induced abortion.

    Science.gov (United States)

    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.

  1. Going All In: Unfavorable Sex Ratios Attenuate Choice Diversification.

    Science.gov (United States)

    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.

  2. 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...

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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

  11. 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 ...

  12. Exploring the possibilities for stabilizing the sex ratio in India

    Directory of Open Access Journals (Sweden)

    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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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...

  18. 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...

  19. 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

  20. Extraordinary sex ratios: cultural effects on ecological consequences.

    Directory of Open Access Journals (Sweden)

    Ferenc Molnár

    Full Text Available We model sex-structured population dynamics to analyze pairwise competition between groups differing both genetically and culturally. A sex-ratio allele is expressed in the heterogametic sex only, so that assumptions of Fisher's analysis do not apply. Sex-ratio evolution drives cultural evolution of a group-associated trait governing mortality in the homogametic sex. The two-sex dynamics under resource limitation induces a strong Allee effect that depends on both sex ratio and cultural trait values. We describe the resulting threshold, separating extinction from positive growth, as a function of female and male densities. When initial conditions avoid extinction due to the Allee effect, different sex ratios cannot coexist; in our model, greater female allocation always invades and excludes a lesser allocation. But the culturally transmitted trait interacts with the sex ratio to determine the ecological consequences of successful invasion. The invading female allocation may permit population persistence at self-regulated equilibrium. For this case, the resident culture may be excluded, or may coexist with the invader culture. That is, a single sex-ratio allele in females and a cultural dimorphism in male mortality can persist; a low-mortality resident trait is maintained by father-to-son cultural transmission. Otherwise, the successfully invading female allocation excludes the resident allele and culture and then drives the population to extinction via a shortage of males. Finally, we show that the results obtained under homogeneous mixing hold, with caveats, in a spatially explicit model with local mating and diffusive dispersal in both sexes.

  1. 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.

  2. 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 ...

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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.

  5. 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...

  6. 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

  7. 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.

  8. Abnormal sex ratios in human populations: causes and consequences.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  10. India’s Distorted Sex Ratio: Dire Consequences for Girls

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  12. 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.

  13. 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

  14. 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 ...

  15. 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.

  16. 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…

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

    Directory of Open Access Journals (Sweden)

    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

  18. [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

  19. 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.

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

    Science.gov (United States)

    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.

  1. 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.

  2. 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.

  3. 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...

  4. Socioeconomic status influences sex ratios in a Chinese rural population.

    Science.gov (United States)

    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.

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. Could changes in reported sex ratios at birth during China's 1958-1961 famine support the adaptive sex ratio adjustment hypothesis?

    Directory of Open Access Journals (Sweden)

    Anna Reimondos

    2013-10-01

    Full Text Available Background: The adaptive sex ratio adjustment hypothesis suggests that when mothers are in poor conditions the sex ratio of their offspring will be biased towards females. Major famines provide opportunities for testing this hypothesis because they lead to the widespread deterioration of living conditions in the affected population. Objective: This study examines changes in sex ratio at birth before, during, and after China's 1958-1961 famine, to see whether they provide any support for the adaptive sex ratio adjustment hypothesis. Methods: We use descriptive statistics to analyse data collected by both China's 1982 and 1988 fertility sample surveys and examine changes in sex ratio at birth in recent history. In addition, we examine the effectiveness of using different methods to model changes in sex ratio at birth and compare their differences. Results: During China's 1958-1961 famine, reported sex ratio at birth remained notably higher than that observed in most countries in the world. The timing of the decline in sex ratio at birth did not coincide with the timing of the famine. After the famine, although living conditions were considerably improved, the sex ratio at birth was not higher but lower than that recorded during the famine. Conclusions: The analysis of the data collected by the two fertility surveys has found no evidence that changes in sex ratio at birth during China's 1958-1961 famine and the post-famine period supported the adaptive sex ratio adjustment hypothesis.

  10. 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.

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

    Science.gov (United States)

    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.

  12. 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

  13. 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.

  14. 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

    mortality has decreased since 1990 for the vast majority of countries with outlying sex ratios, the ratios of estimated to expected female mortality did not change substantially for most countries, and worsened for India. Important differences exist between boys and girls with respect to survival up to the age of 5 years. Survival chances tend to improve more rapidly for girls compared with boys as total mortality decreases, with a reversal of this trend at very low infant mortality. For many countries, sex ratios follow this pattern but important exceptions exist. An explanation needs to be sought for selected countries with outlying sex ratios and action should be undertaken if sex discrimination is present. The National University of Singapore and the United Nations Children's Fund (UNICEF). Copyright © 2014 Alkema et al. Open Access article distributed under the terms of CC BY-NC-SA. Published by .. All rights reserved.

  15. 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...

  16. 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.

  17. 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.

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

    Science.gov (United States)

    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.

  19. 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

  20. Patterns and Processes of Recruitment and Trafficking into sex Work ...

    African Journals Online (AJOL)

    Patterns and Processes of Recruitment and Trafficking into sex Work in Nigeria. ... The recruitment patterns and trafficking processes were characterized with incidences of deception, extortion, violence and ... AJOL African Journals Online.

  1. Sexual orientation, handedness, sex ratio and fetomaternal tolerance-rejection

    Directory of Open Access Journals (Sweden)

    Carlos Y Valenzuela

    2010-01-01

    Full Text Available Fraternal birth order (FBO appears as a prenatal cause of 15% of homosexual males (gays through mnemonic maternal anti-male factors. Non-right-handed men seem to be protected from homosexuality. Four hypotheses are proposed: (1 androgenic factors of non-right-handedness neutralize anti-male factors; (2 non-right-handedness and homosexuality are lethal or produce mental impairment; (3 non-right-handed male embryos are insensitive to anti-male factors; (4 mothers of non-right-handed fetuses do not produce anti-male factors. Studies of the sex ratio (SR of older and younger siblings show: (1 a significant heterogeneity in the SR of siblings of right or non-right handed heterosexual men and women; (2 lesbians are born among siblings with high SR; (3 siblings of right-handed gays show a higher SR than non-right-handed gays that present a low SR. Based on our discovery of maternal tolerance-rejection processes, associated with genetic systems (ABO, Rh, where zygotes or embryos different from their mother induce better pregnancy and maternal tolerance than do those that share antigens with their mothers, I propose a new explanation for sexual relationships, sexual orientation, handedness and sibling SR. Lesbian embryos could induce tolerance from mothers with anti-female factors. Non-right-handedness could induce maternal tolerance, or change the maternal compatibility of "gay" embryos. Alternatively, gay embryos could be poor inducers of maternal tolerance towards male traits.

  2. Sexual orientation, handedness, sex ratio and fetomaternal tolerance-rejection.

    Science.gov (United States)

    Valenzuela, Carlos Y

    2010-01-01

    Fraternal birth order (FBO) appears as a prenatal cause of 15% of homosexual males (gays) through mnemonic maternal anti-male factors. Non-right-handed men seem to be protected from homosexuality. Four hypotheses are proposed: (1) androgenic factors of non-right-handedness neutralize anti-male factors; (2) non-right-handedness and homosexuality are lethal or produce mental impairment; (3) non-right-handed male embryos are insensitive to anti-male factors; (4) mothers of non-right-handed fetuses do not produce anti-male factors. Studies of the sex ratio (SR) of older and younger siblings show: (1) a significant heterogeneity in the SR of siblings of right or non-right handed heterosexual men and women; (2) lesbians are born among siblings with high SR; (3) siblings of right-handed gays show a higher SR than non-right-handed gays that present a low SR. Based on our discovery of maternal tolerance-rejection processes, associated with genetic systems (ABO, Rh), where zygotes or embryos different from their mother induce better pregnancy and maternal tolerance than do those that share antigens with their mothers, I propose a new explanation for sexual relationships, sexual orientation, handedness and sibling SR. Lesbian embryos could induce tolerance from mothers with anti-female factors. Non-right-handedness could induce maternal tolerance, or change the maternal compatibility of "gay" embryos. Alternatively, gay embryos could be poor inducers of maternal tolerance towards male traits.

  3. 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);

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

    Science.gov (United States)

    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…

  5. An unstable social environment affects sex ratio in guinea pigs : an adaptive maternal effect?

    NARCIS (Netherlands)

    Kemme, Kristina; Kaiser, Sylvia; von Engelhardt, Nikolaus; Wewers, Dirk; Groothuis, Ton; Sachser, Norbert

    2009-01-01

    Evolutionary theory suggests that offspring sex should be adjusted to environmental conditions in order to maximize future reproductive success. In several animal taxa environmental factors indeed affect the secondary sex ratio. In humans, changes in the sex ratio at birth have been associated with

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

    Science.gov (United States)

    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…

  7. 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...

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Maternal condition but not corticosterone is linked to offspring sex ratio in a passerine bird.

    Directory of Open Access Journals (Sweden)

    Lindsay J Henderson

    Full Text Available There is evidence of offspring sex ratio adjustment in a range of species, but the potential mechanisms remain largely unknown. Elevated maternal corticosterone (CORT is associated with factors that can favour brood sex ratio adjustment, such as reduced maternal condition, food availability and partner attractiveness. Therefore, the steroid hormone has been suggested to play a key role in sex ratio manipulation. However, despite correlative and causal evidence CORT is linked to sex ratio manipulation in some avian species, the timing of adjustment varies between studies. Consequently, whether CORT is consistently involved in sex-ratio adjustment, and how the hormone acts as a mechanism for this adjustment remains unclear. Here we measured maternal baseline CORT and body condition in free-living blue tits (Cyanistes caeruleus over three years and related these factors to brood sex ratio and nestling quality. In addition, a non-invasive technique was employed to experimentally elevate maternal CORT during egg laying, and its effects upon sex ratio and nestling quality were measured. We found that maternal CORT was not correlated with brood sex ratio, but mothers with elevated CORT fledged lighter offspring. Also, experimental elevation of maternal CORT did not influence brood sex ratio or nestling quality. In one year, mothers in superior body condition produced male biased broods, and maternal condition was positively correlated with both nestling mass and growth rate in all years. Unlike previous studies maternal condition was not correlated with maternal CORT. This study provides evidence that maternal condition is linked to brood sex ratio manipulation in blue tits. However, maternal baseline CORT may not be the mechanistic link between the maternal condition and sex ratio adjustment. Overall, this study serves to highlight the complexity of sex ratio adjustment in birds and the difficulties associated with identifying sex biasing mechanisms.

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

    Science.gov (United States)

    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).

  16. 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

  17. 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....

  18. Sex ratio in two species of Pegoscapus wasps (Hymenoptera: Agaonidae) that develop in figs: can wasps do mathematics, or play sex ratio games?

    Science.gov (United States)

    Ramírez-Benavides, William; Monge-Nájera, Julián; Chavarría, Juan B

    2009-09-01

    The fig pollinating wasps (Hymenoptera: Agaonidae) have obligate arrhenotoky and a breeding structure that fits local mate competition (LMC). It has been traditionally assumed that LMC organisms adjust the sex ratio by laying a greater proportion of male eggs when there is superparasitism (several foundresses in a host). We tested the assumption with two wasp species, Pegoscapus silvestrii, pollinator of Ficus pertusa and Pegoscapus tonduzi, pollinator of Ficus eximia (= F citrifolia), in the Central Valley of Costa Rica. Total number of wasps and seeds were recorded in individual isolated naturally colonized syconia. There was a constant additive effect between the number of foundresses and the number of males produced in the brood of a syconium, while the number of females decreased. Both wasp species seem to have precise sex ratios and probably lay the male eggs first in the sequence, independently of superparasitism and clutch size: consequently, they have a non-random sex allocation. Each syconium of Ficus pertusa and of F. eximia colonized by one foundress had similar mean numbers of females, males, and seeds. The two species of wasps studied do not seem to adjust the sex ratio when there is superparasitism. Pollinating fig wasp behavior is better explained by those models not assuming that females do mathematical calculations according to other females' sex ratios, size, number of foundresses, genetic constitution, clutch size or environmental conditions inside the syconium. Our results are in agreement with the constant male number hypothesis, not with sex ratio games.

  19. No evidence for selective follicle abortion underlying primary sex ratio adjustment in pigeons

    NARCIS (Netherlands)

    Goerlich, Vivian C.; Dijkstra, Cornelis; Groothuis, Antonius

    Primary sex ratio adjustment in birds has been extensively studied, yet the underlying physiological mechanisms are far from understood. Avian females are the heterogametic sex (ZW), and the future sex of the offspring is determined at chromosome segregation during meiosis I, shortly before the

  20. 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,

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

    Science.gov (United States)

    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.

  2. 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.

  3. 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.

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

    Science.gov (United States)

    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.

  5. 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....

  6. 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

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

    Science.gov (United States)

    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...

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

    OpenAIRE

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

    2014-01-01

    Background: 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. Methods: For this systematic anal...

  9. 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...

  10. 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.

  11. Sex Dimorphism of the Heart Diameters and Cardiothoracic Ratios ...

    African Journals Online (AJOL)

    Objective: To determine gender associated differences in the cardiothoracic ratio (CTR) and heart diameters in a normal Nigerian population. Subject and Method: The normal heart diameters and cardiothoracic ratios were measured from posteroanterior (PA) chest radiographs of healthy 510 male and 508 female ...

  12. 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.

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

    Science.gov (United States)

    Vandenbergh, J G; Huggett, C L

    1994-11-08

    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 longer than that of females not between two males (OM). We have found that the IUP, as determined by cesarean section and by an index of the AGD, correlates with the sex ratio of the litters produced by female mice. The sex ratio of the first litter born to 2M females was 58% males, for 1M females was 51% males and for OM females was 42% males. The effect on sex ratio continues into the second litter. The number of pups produced by mothers of different IUPs in her first two litters did not differ, suggesting that the sex ratio adjustment occurs prior to parturition. These results provide a basis for the natural variability observed in sex ratios of litter-bearing mammals and suggest that one or more intrauterine mechanisms may be responsible for environmentally related sex ratio alterations.

  14. 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...

  15. 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

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

    Science.gov (United States)

    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.

  17. 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...

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

    Science.gov (United States)

    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.

  19. Paternal effects on the human sex ratio at birth: evidence from interracial crosses.

    Science.gov (United States)

    Khoury, M J; Erickson, J D; James, L M

    1984-01-01

    The effects of interracial crossing on the human sex ratio at birth were investigated using United States birth-certificate data for 1972-1979. The sex ratio was 1.059 for approximately 14 million singleton infants born to white couples, 1.033 for 2 million born to black couples, and 1.024 for 64,000 born to American Indian couples. Paternal and maternal race influences on the observed racial differences in sex ratio were analyzed using additional data on approximately 97,000 singleton infants born to white-black couples and 60,000 born to white-Indian couples. After adjustment for mother's race, white fathers had significantly more male offspring than did black fathers (ratio of sex ratios [RSR] = 1.027) and Indian fathers (RSR = 1.022). On the other hand, after adjustment for father's race, white mothers did not have more male offspring than did black mothers (RSR = 0.998) or Indian mothers (RSR = 1.009). The paternal-race effect persisted after adjustment for parental ages, education, birth order, and maternal marital status. The study shows that the observed racial differences in the sex ratio at birth are due to the effects of father's race and not the mother's. The study points to paternal determinants of the human sex ratio at fertilization and/or of the prenatal differential sex survival. PMID:6496474

  20. 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.

  1. Sex ratio in two species of Pegoscapus wasps (Hymenoptera: Agaonidae that develop in figs: can wasps do mathematics, or play sex ratio games?

    Directory of Open Access Journals (Sweden)

    William Ramírez-Benavides

    2009-09-01

    Full Text Available The fig pollinating wasps (Hymenoptera: Agaonidae have obligate arrhenotoky and a breeding structure that fits local mate competition (LMC. It has been traditionally assumed that LMC organisms adjust the sex ratio by laying a greater proportion of male eggs when there is superparasitism (several foundresses in a host. We tested the assumption with two wasp species, Pegoscapus silvestrii, pollinator of Ficus pertusa and Pegoscapus tonduzi, pollinator of Ficus eximia (= F. citrifolia, in the Central Valley of Costa Rica. Total number of wasps and seeds were recorded in individual isolated naturally colonized syconia. There was a constant additive effect between the number of foundresses and the number of males produced in the brood of a syconium, while the number of females decreased. Both wasp species seem to have precise sex ratios and probably lay the male eggs first in the sequence, independently of superparasitism and clutch size: consequently, they have a non-random sex allocation. Each syconium of Ficus pertusa and of F. eximia colonized by one foundress had similar mean numbers of females, males, and seeds. The two species of wasps studied do not seem to adjust the sex ratio when there is superparasitism. Pollinating fig wasp behavior is better explained by those models not assuming that females do mathematical calculations according to other females’ sex ratios, size, number of foundresses, genetic constitution, clutch size or environmental conditions inside the syconium. Our results are in agreement with the constant male number hypothesis, not with sex ratio games. Rev. Biol. Trop. 57 (3: 605-621. Epub 2009 September 30.

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

    Science.gov (United States)

    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.

  3. Persistent sex-by-environment effects on offspring fitness and sex-ratio adjustment in a wild bird population.

    Science.gov (United States)

    Bowers, E Keith; Thompson, Charles F; Sakaluk, Scott K

    2015-03-01

    A major component of sex-allocation theory, the Trivers-Willard model (TWM), posits that sons and daughters are differentially affected by variation in the rearing environment. In many species, the amount of parental care received is expected to have differing effects on the fitness of males and females. When this occurs, the TWM predicts that selection should favour adjustment of the offspring sex ratio in relation to the expected fitness return from offspring. However, evidence for sex-by-environment effects is mixed, and little is known about the adaptive significance of producing either sex. Here, we test whether offspring sex ratios vary according to predictions of the TWM in the house wren (Troglodytes aedon, Vieillot). We also test the assumption of a sex-by-environment effect on offspring using two experiments, one in which we manipulated age differences among nestlings within broods, and another in which we held nestling age constant but manipulated brood size. As predicted, females with high investment ability overproduced sons relative to those with lower ability. Males were also overproduced early within breeding seasons. In our experiments, the body mass of sons was more strongly affected by the sibling-competitive environment and resource availability than that of daughters: males grew heavier than females when reared in good conditions but were lighter than females when in poor conditions. Parents rearing broods with 1:1 sex ratios were more productive than parents rearing broods biased more strongly towards sons or daughters, suggesting that selection favours the production of mixed-sex broods. However, differences in the condition of offspring as neonates persisted to adulthood, and their reproductive success as adults varied with the body mass of sons, but not daughters, prior to independence from parental care. Thus, selection should favour slight but predictable variations in the sex ratio in relation to the quality of offspring that parents are

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  7. 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...

  8. 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

  9. 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

  10. 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

  11. 3. Pattern of Inheritance of Autosome and Sex. Chromosome Linked ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 4; Issue 10. Teaching and Learning Genetics with Drosophila – Pattern of Inheritance of Autosome and Sex Chro-mosome Linked Genes/Characters. H A Ranganath M T Tanuja. Classroom Volume 4 Issue 10 October 1999 pp 78-87 ...

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  14. 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....

  15. 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...

  16. 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...

  17. 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

  18. 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.

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

    Science.gov (United States)

    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.

  20. 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...

  1. 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,

  2. 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....

  3. 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.

  4. 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.

  5. 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.

  6. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. 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

  9. 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

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

    Science.gov (United States)

    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.

  11. 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.

  12. 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.

  13. 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...

  14. 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.

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

    Science.gov (United States)

    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

  16. 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.   

  17. 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

  18. 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...

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Genes and chromosome arrangements affecting sex ratio in the Mediterranean fruit fly, Ceratitis capitata (Wied.)

    International Nuclear Information System (INIS)

    Wood, R.J.; Kafu, A.A.; Rendon Arana, P.A.; Owusu-Daaku, K.; Alcock, R.M.; Hallows, J.A.; Busch-Petersen, E.; Mani, G.S.

    1997-01-01

    The MP (male producing) factor, which shows temperature sensitive meiotic drive favoring the Y chromosome, proved to be highly variable in spermatozoal deficiency in different cysts within a single testis. However, the overall loss of sperm corresponded almost precisely with the loss of females. The minimum proportion of females consistently obtained in inbred lines was about 30-35%. On the basis of parallel studies with the mosquito Aedes aegypti, variability between cysts is open to interpretation in terms of different rates of senescence. The T:Y(wp + )30C genetic sexing strain, which is designed to generate males with brown (wild type) puparia and females with white puparia, was contaminated artificially in a series of population experiments to investigate the pattern of breakdown. Wild type contamination with either sex caused an increase of brown pupae. The sex ratio became progressively distorted in favour of females after contamination with females, mated or unmated, but not after male contamination. The experiments revealed evidence of a low frequency of natural recombination between wp + and the translocation breakpoint on the Y chromosome, shown by the appearance of wp males. The frequency of male recombination (r) and the selection coefficient (s) against wp/wp were measured over 11 generations. The best fit to the observed data was obtained with r = (0.14 ± 0.04)% and s=(26.0 ± 2.7)%. Using these estimates to predict the frequency of wp + females and wp males for up to 100 generations, it was concluded that white males would never exceed 0.5% whereas the frequency of brown females was expected to exceed 33% after 25 generations. Published data on the mass reared strain, maintained with a population size of 240,000 adult flies, were subjected to the same analysis. A higher value of s between (38.0 ± 3.2)% and (52.0 ± 0.3)% was obtained under these conditions. Electrophoretic studies on esterases revealed a significantly higher activity in a recently

  1. Behavioral tactics of male sockeye salmon (Oncorhynchus nerka) under varying operating sex ratios

    Science.gov (United States)

    Quinn, Thomas P.; Adkison, Milo D.; Ward, Michael B.

    1996-01-01

    Previous studies have demonstrated several reproductive-behavior patterns in male salmon, including competitive and sneaking tactics, the formation of hierarchies, and non-hierarchical aggregations around ripe females. Through behavioral observations at varying spatial and temporal scales, we examined the hypothesis that operational sex ratio (OSR) determines male sockeye salmon (Oncorhynchus nerka) distribution and breeding tactics. Patterns of male distribution and behavior varied over both coarse and fine scales, associated with apparent shifts in reproductive opportunities, the physical characteristics of the breeding sites, and the deterioration of the fish as they approached death. Females spawned completely within a few days of arriving on the spawning grounds, whereas males courted the available ripe females from the date of their arrival on the spawning ground until their death. This difference in reproductive lifespans tended to elevate late-season OSRs but was partially counterbalanced by male departures and the arrival of other ripe females. The proportion of males able to dominate access to ripe females decreased and the number of large courting groups increased over the course of the season, apparently related to both increasing OSR and the deteriorating physical condition of males. However, great variation in OSR was observed within the spawning sites on a given day. OSRs were generally higher in shallow than in deep water, perhaps because larger females or more desirable breeding sites were concentrated in shallow water. The aggregations of males courting females were not stable (i.e. many arrivals and departures took place) and male aggression varied with group size. Aggression was most frequent at low OSRs and in groups of intermediate size (2–4 males per female), and much less frequent in larger groups, consistent with the needs of maximizing reproductive opportunities while minimizing unproductive energy expenditure. These results indicate

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

    Directory of Open Access Journals (Sweden)

    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.

  3. 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.

  4. [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.

  5. 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...

  6. 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…

  7. 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.

  8. 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

  9. 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

  10. Female starlings adjust primary sex ratio in response to aromatic plants in the nest.

    Science.gov (United States)

    Polo, Vicente; Veiga, José P; Cordero, Pedro J; Viñuela, Javier; Monaghan, Pat

    2004-09-22

    Adjustment of offspring sex ratios should be favoured by natural selection when parents are capable of facultatively altering brood sex ratios and of recognizing the circumstances that predict the probable fitness benefit of producing sons and daughters. Although experimental studies have shown that female birds may adjust offspring sex ratios in response to changes in their own condition and in the external appearance of their mate, and male attributes other than his external morphology are also thought to act as signals of male quality, it is not known whether females will respond to changes in such signals, in the absence of any change in the appearance of the male himself. Here, we experimentally manipulated a male courtship display, the green plants carried to the nest by male spotless starlings (Sturnus unicolor), without changing any physical attributes of the male himself, and examined whether this influenced female decisions on offspring sex ratio. We found that in an environment in which female starlings were producing more daughters than sons, experimental enhancement of the green nesting material caused females to significantly increase the number of male eggs produced and thereby removed the female bias. This effect was consistent in 2 years and at two localities. This demonstrates that the green material, whose function has long puzzled biologists, conveys important information to the female and that she facultatively adjusts offspring production accordingly.

  11. 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 ...

  12. 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

  13. 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

  14. 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...

  15. 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.

  16. Sex differences in Hadza dental wear patterns : a preliminary report.

    Science.gov (United States)

    Berbesque, J Colette; Marlowe, Frank W; Pawn, Ian; Thompson, Peter; Johnson, Guy; Mabulla, Audax

    2012-09-01

    Among hunter-gatherers, the sharing of male and female foods is often assumed to result in virtually the same diet for males and females. Although food sharing is widespread among the hunting and gathering Hadza of Tanzania, women were observed eating significantly more tubers than men. This study investigates the relationship between patterns of dental wear, diet, and extramasticatory use of teeth among the Hadza. Casts of the upper dentitions were made from molds taken from 126 adults and scored according to the Murphy dental attrition scoring system. Females had significantly greater anterior occlusal wear than males when we controlled for age. Males exhibited greater asymmetry in wear, with greater wear on the left side in canines, first premolars, and first molars. We suggest that these sex differences in wear patterns reflect the differences seen in the diet, as well as in the use of teeth as tools.

  17. Sex- and Size-Related Patterns of Carrion Visitation in Necrodes littoralis (Coleoptera: Silphidae) and Creophilus maxillosus (Coleoptera: Staphylinidae).

    Science.gov (United States)

    Mądra-Bielewicz, Anna; Frątczak-Łagiewska, Katarzyna; Matuszewski, Szymon

    2017-09-01

    The estimation of postmortem interval (PMI) based on successional patterns of adult insects is largely limited, due to the lack of potential PMI markers. Sex and size of adult insects could be easily used for such estimation. In this study, sex- and size-related patterns of carrion attendance by adult insects were analyzed in Necrodes littoralis (Coleoptera: Silphidae) and Creophilus maxillosus (Coleoptera: Staphylinidae). For both species, abundance of males and females changed similarly during decomposition. A slightly female-biased sex ratio was recorded in N. littoralis. Females of N. littoralis started visiting carcasses, on average, one day earlier than males. There was a rise in size of males of N. littoralis at the end of decomposition, whereas for females of both species and males of C. maxillosus, no size-related patterns of carrion visitation were found. Current results demonstrate that size and sex of adult carrion beetles are poor indicators of PMI. © 2016 American Academy of Forensic Sciences.

  18. 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...

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

    Science.gov (United States)

    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.

  20. 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.

  1. Transgenerational plasticity mitigates the impact of global warming to offspring sex ratios.

    Science.gov (United States)

    Donelson, Jennifer M; Munday, Philip L

    2015-08-01

    Global warming poses a threat to organisms with temperature-dependent sex determination because it can affect operational sex ratios. Using a multigenerational experiment with a marine fish, we provide the first evidence that parents developing from early life at elevated temperatures can adjust their offspring gender through nongenetic and nonbehavioural means. However, this adjustment was not possible when parents reproduced, but did not develop, at elevated temperatures. Complete restoration of the offspring sex ratio occurred when parents developed at 1.5 °C above the present-day average temperature for one generation. However, only partial improvement in the sex ratio occurred at 3.0 °C above average conditions, even after two generations, suggesting a limitation to transgenerational plasticity when developmental temperature is substantially increased. This study highlights the potential for transgenerational plasticity to ameliorate some impacts of climate change and that development from early life may be essential for expression of transgenerational plasticity in some traits. © 2015 John Wiley & Sons Ltd.

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

    Directory of Open Access Journals (Sweden)

    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

  3. Causes and consequences of adult sex ratio imbalance in a historical U.S. population.

    Science.gov (United States)

    Schacht, Ryan; Smith, Ken R

    2017-09-19

    The responsiveness of individuals to partner availability has been well-documented across the literature. However, there is disagreement regarding the direction of the consequences of sex ratio imbalance. Specifically, does an excess of males or females promote male-male mating competition? In an attempt to clarify the role of the adult sex ratio (ASR) on behaviour, here we evaluate both competing and complimentary expectations derived from theory across the social and biological sciences. We use data drawn from a historical, nineteenth century population in North America and target several life-history traits thought to be affected by partner availability: age at first birth, relationship status, completed fertility and longevity. Furthermore, we assess the role of various contributors to a population's ASR. We find that both the contributors to and consequences of sex ratio imbalance vary over time. Our results largely support predictions of greater male pairbond commitment and lesser male mating effort, as well as elevated bargaining power of women in response to female scarcity. After reviewing our findings, and others from across the literature, we highlight the need to adjust predictions in response to ASR imbalance by the: (i) culturally mediated mating arena, (ii) variable role of demographic inputs across time and place, (iii) constraints to behavioural outcomes across populations, and (iv) ability and accuracy of individuals to assess partner availability.This article is part of the themed issue 'Adult sex ratios and reproductive strategies: a critical re-examination of sex differences in human and animal societies'. © 2017 The Author(s).

  4. Analysis of sex-specific injury patterns and risk factors in young high-level athletes.

    Science.gov (United States)

    Frisch, A; Seil, R; Urhausen, A; Croisier, J L; Lair, M L; Theisen, D

    2009-12-01

    This study analyzed sex-specific injury patterns and risk factors in young athletes (n=256) from 12 sport disciplines practicing at the national or the international level in the Grand-Duchy of Luxembourg. Injury occurrence as a result of sport practice was analyzed retrospectively over the year 2006 using a standardized self-administered questionnaire. Overall incidence was not different between girls and boys (1.20 and 1.21 injuries/1000 athlete-hours, respectively), but in the context of team sport competition girls tended to be at a greater risk (rate ratio 2.05, P=0.053). Girls had a higher proportion of injuries in the ankle/foot region compared with boys (34.8% vs 16.8%). No sex-related differences were found regarding injury severity. Multivariate logistic regression (controlling for age and practice volume) revealed that girls' team sports were associated with a greater injury risk compared with individual sports [odds ratio (OR) of 4.76], while in boys this was observed for racket sports (OR=3.31). Furthermore, physical or emotional stress tended to be a specific risk factor in girls. There was a tendency for injury outside sports to be coupled to a higher injury risk in girls and boys. Consideration of sex-specific injury patterns and risk factors could be of importance for effective injury prevention.

  5. Effects of age and sex ratios on offspring recruitment rates in translocated black rhinoceros.

    Science.gov (United States)

    Gedir, Jay V; Law, Peter R; du Preez, Pierre; Linklater, Wayne L

    2018-06-01

    Success of animal translocations depends on improving postrelease demographic rates toward establishment and subsequent growth of released populations. Short-term metrics for evaluating translocation success and its drivers, like postrelease survival and fecundity, are unlikely to represent longer-term outcomes. We used information theory to investigate 25 years of data on black rhinoceros (Diceros bicornis) translocations. We used the offspring recruitment rate (ORR) of translocated females-a metric integrating survival, fecundity, and offspring recruitment at sexual maturity-to detect determinants of success. Our unambiguously best model (AICω = 0.986) predicted that ORR increases with female age at release as a function of lower postrelease adult rhinoceros sex ratio (males:females). Delay of first postrelease reproduction and failure of some females to recruit any calves to sexual maturity most influenced the pattern of ORRs, and the leading causes of recruitment failure were postrelease female death (23% of all females) and failure to calve (24% of surviving females). We recommend translocating older females (≥6 years old) because they do not exhibit the reproductive delay and low ORRs of juveniles (recruitment failure of juveniles and young adults (4-5.9 years old). Where translocation of juveniles is necessary, they should be released into female-biased populations, where they have higher ORRs. Our study offers the unique advantage of a long-term analysis across a large number of replicate populations-a science-by-management experiment as a proxy for a manipulative experiment, and a rare opportunity, particularly for a large, critically endangered taxon such as the black rhinoceros. Our findings differ from previous recommendations, reinforce the importance of long-term data sets and comprehensive metrics of translocation success, and suggest attention be shifted from ecological to social constraints on population growth and species recovery, particularly

  6. 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.

  7. 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...

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  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.

  15. 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...

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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...

  4. 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.

  5. 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.

  6. Interference patterns and extinction ratio of the diatom Coscinodiscus granii

    DEFF Research Database (Denmark)

    Maibohm, Christian; Friis, Søren Michael Mørk; Ellegaard, M.

    2015-01-01

    We report experimental and theoretical verification of the nature and position of multiple interference points of visible light transmitted through the valve of the centric diatom species Coscinodiscus granii. Furthermore, by coupling the transmitted light into an optical fiber and moving...... the diatom valve between constructive and destructive interference points, an extinction ratio of 20 dB is shown...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  9. 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.

  10. 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...

  11. 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...

  12. Plant species occurrence patterns in Eurasian grasslands reflect adaptation to nutrient ratios

    NARCIS (Netherlands)

    Roeling, Ineke S.; Ozinga, Wim A.; van Dijk, Jerry; Eppinga, Maarten B.; Wassen, Martin J.

    2018-01-01

    Previous studies of Eurasian grasslands have suggested that nutrient ratios, rather than absolute nutrient availabilities and associated productivity, may be driving plant species richness patterns. However, the underlying assumption that species occupy distinct niches along nutrient ratio gradients

  13. Seasonal changes in the gonadossomatic index, allometric condition factor and sex ratio of an auchenipterid catfish from eastern Amazonia

    Directory of Open Access Journals (Sweden)

    Tiago Magalhães da Silva Freitas

    Full Text Available The aim of the present study was to evaluate the seasonal pattern of the gonadosomatic index (GSI, condition factor (K, and sex ratio in the catfish Auchenipterichthys longimanus (Siluriformes: Auchenipteridae as an approach to identify its reproductive period. A total of 589 A. longimanus specimens (251 males and 338 females were captured in the rivers of the Caxiuanã National Forest, in the Brazilian state of Pará, between July, 2008 and July, 2009. Among the male specimens, 171 were classified as adults and 80 as juveniles, while there were 249 adults and 89 juvenile females. Using a sinusoidal equation, analysis of the GSI revealed a reproductive asynchrony between the genders, with males attaining their highest GSI values in January, while females peaked in March. For males, the sinusoidal regression for GSI values was significant only when used the complete data set (P=0.001, wears no trend was identified for bimonthly means (P=0.136. For females, by contrast, significant values were obtained for both the complete data set (P=0.012 and bimonthly GSI means (P=0.026. For the condition factor, the sinusoidal equation returned significant seasonal variation in both raw data (P=0.02 and with mean values (P=0.00 for males, but only with raw data for females (P=0.04, which appears to reflect variation in the energy budget between genders. With regard to the sex ratio, more reproductive females were captured than males in January and March, 2009, which suggests a pattern of segregation related to the reproductive process. These parameters are fundamental to the assessment, protection, and management of natural fish stocks, as well as providing guidelines for the development of conservation strategies.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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...

  1. Planktonic benthonic foraminiferal ratios: Modern patterns and Tertiary applicability

    Science.gov (United States)

    Gibson, T.G.

    1989-01-01

    The abundance of planktonic specimens in foraminiferal assemblages was determined in numerous bottom samples from inner neritic to deep oceanic depths along the Atlantic margin of the northeastern United States. The results augment previous studies in other areas that have shown a general increase in percentage of planktonic specimens in total foraminiferal bottom assemblages as water depth increases. The patterns found in this area of complex shelf bathymetry and hydrography illustrate the influence on the planktonic-benthonic percentages of water depth, distance from shore, different water mass properties and downslope movement of tests in high energy areas. The patterns found in the 661 samples from the Atlantic margin were compared with results from 795 stations in the Gulf of Mexico, Pacific Ocean and Red Sea. The relative abundance of planktonic specimens and water depth correlates positively in all open oceanic areas even though taxonomic composition and diversity of the faunas from different areas is variable. The variation of planktonic percentages in bottom samples within most depth intervals is large so that a precise depth determination cannot be made for any given value. However, an approximate upper depth limit for given percentages can be estimated for open ocean environments. A decrease in planktonic percentages is seen in the lower salinity and higher turbidity coastal waters of the Gulf of Maine. Planktonic percentages intermediate between the lower values in the less saline coastal waters and the higher values in the normal open oceanic conditions occur in the transitional area between the Gulf of Maine and the open marine Atlantic Ocean to the east. Similarly lowered values in another area of restricted oceanic circulation occur in the high salinity, clear, but nutrient-poor waters of the Gulf of Aqaba off the Red Sea. A comparison of the similarity of modern planktonic percentage values to those found in earlier Tertiary assemblages was made to

  2. 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...

  3. 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

  4. 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.

  5. 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

  6. Ecological and pest-management implications of sex differences in scarab landing patterns on grape vines.

    Science.gov (United States)

    González-Chang, Mauricio; Boyer, Stéphane; Lefort, Marie-Caroline; Nboyine, Jerry; Wratten, Steve D

    2017-01-01

    Melolonthinae beetles, comprising different white grub species, are a globally-distributed pest group. Their larvae feed on roots of several crop and forestry species, and adults can cause severe defoliation. In New Zealand, the endemic scarab pest Costelytra zealandica (White) causes severe defoliation on different horticultural crops, including grape vines ( Vitis vinifera ). Understanding flight and landing behaviours of this pest can help inform pest management decisions. Adult beetles were counted and then removed from 96 grape vine plants from 21:30 until 23:00 h, every day from October 26 until December 2, during 2014 and 2015. Also, adults were removed from the grape vine foliage at dusk 5, 10, 15, 20 and 25 min after flight started on 2015. Statistical analyses were performed using generalised linear models with a beta-binomial distribution to analyse proportions and with a negative binomial distribution for beetle abundance. By analysing C. zealandica sex ratios during its entire flight season, it is clear that the proportion of males is higher at the beginning of the season, gradually declining towards its end. When adults were successively removed from the grape vines at 5-min intervals after flight activity begun, the mean proportion of males ranged from 6-28%. The male proportion suggests males were attracted to females that had already landed on grape vines, probably through pheromone release. The seasonal and daily changes in adult C. zealandica sex ratio throughout its flight season are presented for the first time. Although seasonal changes in sex ratio have been reported for other melolonthines, changes during their daily flight activity have not been analysed so far. Sex-ratio changes can have important consequences for the management of this pest species, and possibly for other melolonthines, as it has been previously suggested that C. zealandica females land on plants that produce a silhouette against the sky. Therefore, long-term management

  7. Ecological and pest-management implications of sex differences in scarab landing patterns on grape vines

    Directory of Open Access Journals (Sweden)

    Mauricio González-Chang

    2017-04-01

    Full Text Available Background Melolonthinae beetles, comprising different white grub species, are a globally-distributed pest group. Their larvae feed on roots of several crop and forestry species, and adults can cause severe defoliation. In New Zealand, the endemic scarab pest Costelytra zealandica (White causes severe defoliation on different horticultural crops, including grape vines (Vitis vinifera. Understanding flight and landing behaviours of this pest can help inform pest management decisions. Methods Adult beetles were counted and then removed from 96 grape vine plants from 21:30 until 23:00 h, every day from October 26 until December 2, during 2014 and 2015. Also, adults were removed from the grape vine foliage at dusk 5, 10, 15, 20 and 25 min after flight started on 2015. Statistical analyses were performed using generalised linear models with a beta-binomial distribution to analyse proportions and with a negative binomial distribution for beetle abundance. Results By analysing C. zealandica sex ratios during its entire flight season, it is clear that the proportion of males is higher at the beginning of the season, gradually declining towards its end. When adults were successively removed from the grape vines at 5-min intervals after flight activity begun, the mean proportion of males ranged from 6–28%. The male proportion suggests males were attracted to females that had already landed on grape vines, probably through pheromone release. Discussion The seasonal and daily changes in adult C. zealandica sex ratio throughout its flight season are presented for the first time. Although seasonal changes in sex ratio have been reported for other melolonthines, changes during their daily flight activity have not been analysed so far. Sex-ratio changes can have important consequences for the management of this pest species, and possibly for other melolonthines, as it has been previously suggested that C. zealandica females land on plants that produce a

  8. 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.

  9. Low reproductive skew despite high male-biased operational sex ratio in a glass frog with paternal care.

    Science.gov (United States)

    Mangold, Alexandra; Trenkwalder, Katharina; Ringler, Max; Hödl, Walter; Ringler, Eva

    2015-09-03

    Reproductive skew, the uneven distribution of reproductive success among individuals, is a common feature of many animal populations. Several scenarios have been proposed to favour either high or low levels of reproductive skew. Particularly a male-biased operational sex ratio and the asynchronous arrival of females is expected to cause high variation in reproductive success among males. Recently it has been suggested that the type of benefits provided by males (fixed vs. dilutable) could also strongly impact individual mating patterns, and thereby affecting reproductive skew. We tested this hypothesis in Hyalinobatrachium valerioi, a Neotropical glass frog with prolonged breeding and paternal care. We monitored and genetically sampled a natural population in southwestern Costa Rica during the breeding season in 2012 and performed parentage analysis of adult frogs and tadpoles to investigate individual mating frequencies, possible mating preferences, and estimate reproductive skew in males and females. We identified a polygamous mating system, where high proportions of males (69 %) and females (94 %) reproduced successfully. The variance in male mating success could largely be attributed to differences in time spent calling at the reproductive site, but not to body size or relatedness. Female H. valerioi were not choosy and mated indiscriminately with available males. Our findings support the hypothesis that dilutable male benefits - such as parental care - can favour female polyandry and maintain low levels of reproductive skew among males within a population, even in the presence of direct male-male competition and a highly male-biased operational sex ratio. We hypothesize that low male reproductive skew might be a general characteristic in prolonged breeders with paternal care.

  10. Education and gender bias in the sex ratio at birth: evidence from India.

    Science.gov (United States)

    Echávarri, Rebeca A; Ezcurra, Roberto

    2010-02-01

    This article investigates the possible existence of a nonlinear link between female disadvantage in natality and education. To this end, we devise a theoretical model based on the key role of social interaction in explaining people's acquisition of preferences, which justifies the existence of a nonmonotonic relationship between female disadvantage in natality and education. The empirical validity of the proposed model is examined for the case of India, using district-level data. In this context, our econometric analysis pays particular attention to the role of spatial dependence to avoid any potential problems of misspecification. The results confirm that the relationship between the sex ratio at birth and education in India follows an inverted U-shape. This finding is robust to the inclusion of additional explanatory variables in the analysis, and to the choice of the spatial weight matrix used to quantify the spatial interdependence between the sample districts.

  11. Population and colony-level determinants of tertiary sex ratio in the declining barn swallow.

    Directory of Open Access Journals (Sweden)

    Nicola Saino

    Full Text Available Sex ratio of adults (tertiary sex ratio, TSR is a major feature of animal populations with consequences for their behaviour, genetic structure and viability. Spatial and temporal variation in TSR occurs within species but the mechanisms behind it are poorly understood. In this long-term study of a declining population of a socially monogamous, colonial, migratory bird, the barn swallow (Hirundo rustica, we first analyzed population-level variation in TSR ( =  proportion of males of yearlings at sexual maturation in relation to ecological conditions as gauged by annual survival rate of adults. TSR was male-biased both among yearlings and older individuals, but male bias of yearlings was more pronounced after years with larger decline in adult survival. Thus, male offspring were less susceptible to the adverse ecological conditions that cause increased mortality. Dispersal and settling site decisions can have major consequences on fitness via the effects of local TSR on mating and sperm competition. Breeding barn swallows are highly philopatric while natal dispersal is high and, together with mortality, is the main determinant of colony TSR. We thus also investigated the mechanisms of breeding colony choice by yearlings and found that TSR of new-settlers in a given colony and year was negatively predicted by TSR of returning, early arriving older individuals in that year, but not by overall TSR at the colony in the previous year. This suggests that in our male-biased population new-settler males respond to local TSR upon arrival to choose the sites with larger breeding opportunities. Hence, variation in ecological conditions as reflected by adult survival can shift the TSR of individuals recruiting into a local population, with potentially various demographic consequences. However, breeding site choice based on TSR tends to homogenize TSR at a population level likely by facilitating settling of dispersing males in colonies with less male

  12. 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)

  13. Sex differences in confidence influence patterns of conformity.

    Science.gov (United States)

    Cross, Catharine P; Brown, Gillian R; Morgan, Thomas J H; Laland, Kevin N

    2017-11-01

    Lack of confidence in one's own ability can increase the likelihood of relying on social information. Sex differences in confidence have been extensively investigated in cognitive tasks, but implications for conformity have not been directly tested. Here, we tested the hypothesis that, in a task that shows sex differences in confidence, an indirect effect of sex on social information use will also be evident. Participants (N = 168) were administered a mental rotation (MR) task or a letter transformation (LT) task. After providing an answer, participants reported their confidence before seeing the responses of demonstrators and being allowed to change their initial answer. In the MR, but not the LT, task, women showed lower levels of confidence than men, and confidence mediated an indirect effect of sex on the likelihood of switching answers. These results provide novel, experimental evidence that confidence is a general explanatory mechanism underpinning susceptibility to social influences. Our results have implications for the interpretation of the wider literature on sex differences in conformity. © 2016 The British Psychological Society.

  14. EFFECTS OF STRESSFUL EVENTS IN FRANCE (1968) AND JAPAN (1995) ON THE SEX RATIO AT BIRTH.

    Science.gov (United States)

    Grech, Victor; Zammit, Dorota; Scherb, Hagen

    2017-09-01

    Males are usually born in excess of females. The sex ratio at birth (SR) is often expressed as the ratio of male to total births. A wide variety of factors have been shown to influence SR, including terrorist attacks, which have been shown to reduce SR. This paper reviews the effects on SR outcomes of the stressful events in France in 1968 (in association with the student and worker riots) and in Japan following the Aum Shinrikyo religious cult's attack on the Tokyo subway using sarin nerve gas in 1995. Both countries displayed seasonal variation in SR. France exhibited a decline in SR in 1968 (p=0.042), with a particularly strong dip in May of that year (p=0.015). For Japan, there was no statistically significant dip for 1995 but there was a significant dip in June of that year (p=0.026). The SR dips follow catastrophic or tragic events if these are perceived to be momentous enough by a given populace. It is believed that SR slumps may be caused by population stress, which is known to lead to the culling of frail/small male fetuses. It has been observed that these fluctuations are comparable in intensity to a substantial proportion of quoted values for perinatal mortality, potentially making this a public health issue.

  15. 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.

  16. 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...

  17. 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

  18. 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.

  19. 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.

  20. Do brood sex ratio, nestling development and sex affect fledging timing and order? An experimental study on great tits

    NARCIS (Netherlands)

    Radersma, Reinder; Tinbergen, Joost M.; Komdeur, Jan

    The process of nest leaving (fledging) in hole-breeding passerines is largely unexplored, although it is potentially an important facet of reproduction. We used the great tit, Parus major, to investigate whether fledging timing and order were affected by nestling development and sex, as well as the

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

    Science.gov (United States)

    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

  2. Changes in Income at Macro Level Predict Sex Ratio at Birth in OECD Countries.

    Science.gov (United States)

    Kanninen, Ohto; Karhula, Aleksi

    2016-01-01

    The human sex ratio at birth (SRB) is approximately 107 boys for every 100 girls. SRB was rising until the World War II and has been declining slightly after the 1950s in several industrial countries. Recent studies have shown that SRB varies according to exposure to disasters and socioeconomic conditions. However, it remains unknown whether changes in SRB can be explained by observable macro-level socioeconomic variables across multiple years and countries. Here we show that changes in disposable income at the macro level positively predict SRB in OECD countries. A one standard deviation increase in the change of disposable income is associated with an increase of 1.03 male births per 1000 female births. The relationship is possibly nonlinear and driven by extreme changes. The association varies from country to country being particular strong in Estonia. This is the first evidence to show that economic and social conditions are connected to SRB across countries at the macro level. This calls for further research on the effects of societal conditions on general characteristics at birth.

  3. Outline on populations of Nagasaki A-bomb survivors and sex ratio in their children

    International Nuclear Information System (INIS)

    Yoshikawa, Isao; Inoue, Akira; Shiomi, Toshio

    1978-01-01

    On the basis of file delivered together with A-bomb surrivor's health Cards in Nagasaki, statistical management was performed on a mass of A-bomb survivors. The number of A-bomb survivors in a mass was 97,032. A family investigation by census registration was performed on 2,547 of A-bomb survivor group (the distance from the center of explosion recorded on cards was within 1.5 km) and 2,791 of its control group. As to 2,547 of A-bomb survivor group, each exposure place was determined, the distance from the center of explosion was measured again, and exposure dose was presumed. The mean exposure dose of A-bomb survivor group was 577 rad in male, and 681 rad in female. By adding A-bomb survivor group to the control group, 4,452 pairs of marriage were confirmed by census registration, and the number of their children was 10,073. With respect to changes of sex ratio, in case of exposed mother, it was expected theoretically that the number of male would decrease together with an decrease of dose, but an opposite change was recognized in a result of the investigation. A result in case of exposed father showed an increase of the male number although not significantly and a change towards the expected direction. (Tsunoda, M.)

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. Hyperbolically Patterned 3D Graphene Metamaterial with Negative Poisson's Ratio and Superelasticity.

    Science.gov (United States)

    Zhang, Qiangqiang; Xu, Xiang; Lin, Dong; Chen, Wenli; Xiong, Guoping; Yu, Yikang; Fisher, Timothy S; Li, Hui

    2016-03-16

    A hyperbolically patterned 3D graphene metamaterial (GM) with negative Poisson's ratio and superelasticity is highlighted. It is synthesized by a modified hydrothermal approach and subsequent oriented freeze-casting strategy. GM presents a tunable Poisson's ratio by adjusting the structural porosity, macroscopic aspect ratio (L/D), and freeze-casting conditions. Such a GM suggests promising applications as soft actuators, sensors, robust shock absorbers, and environmental remediation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Sex hormones affect acute and chronic stress responses in sexually dimorphic patterns: Consequences for depression models.

    Science.gov (United States)

    Guo, Lei; Chen, Yi-Xi; Hu, Yu-Ting; Wu, Xue-Yan; He, Yang; Wu, Juan-Li; Huang, Man-Li; Mason, Matthew; Bao, Ai-Min

    2018-05-21

    Alterations in peripheral sex hormones may play an important role in sex differences in terms of stress responses and mood disorders. It is not yet known whether and how stress-related brain systems and brain sex steroid levels fluctuate in relation to changes in peripheral sex hormone levels, or whether the different sexes show different patterns. We aimed to investigate systematically, in male and female rats, the effect of decreased circulating sex hormone levels following gonadectomy on acute and chronic stress responses, manifested as changes in plasma and hypothalamic sex steroids and hypothalamic stress-related molecules. Experiment (Exp)-1: Rats (14 males, 14 females) were gonadectomized or sham-operated (intact); Exp-2: gonadectomized and intact rats (28 males, 28 females) were exposed to acute foot shock or no stressor; and Exp-3: gonadectomized and intact rats (32 males, 32 females) were exposed to chronic unpredictable mild stress (CUMS) or no stressor. For all rats, plasma and hypothalamic testosterone (T), estradiol (E2), and the expression of stress-related molecules were determined, including corticotropin-releasing hormone, vasopressin, oxytocin, aromatase, and the receptors for estrogens, androgens, glucocorticoids, and mineralocorticoids. Surprisingly, no significant correlation was observed in terms of plasma sex hormones, brain sex steroids, and hypothalamic stress-related molecule mRNAs (p > 0.113) in intact or gonadectomized, male or female, rats. Male and female rats, either intact or gonadectomized and exposed to acute or chronic stress, showed different patterns of stress-related molecule changes. Diminished peripheral sex hormone levels lead to different peripheral and central patterns of change in the stress response systems in male and female rats. This has implications for the choice of models for the study of the different types of mood disorders which also show sex differences. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Molecular signature of epistatic selection: interrogating genetic interactions in the sex-ratio meiotic drive of Drosophila simulans.

    Science.gov (United States)

    Chevin, Luis-Miguel; Bastide, Héloïse; Montchamp-Moreau, Catherine; Hospital, Frédéric

    2009-06-01

    Fine scale analyses of signatures of selection allow assessing quantitative aspects of a species' evolutionary genetic history, such as the strength of selection on genes. When several selected loci lie in the same genomic region, their epistatic interactions may also be investigated. Here, we study how the neutral polymorphism pattern was shaped by two close recombining loci that cause 'sex-ratio' meiotic drive in Drosophila simulans, as an example of strong selection with potentially strong epistasis. We compare the polymorphism data observed in a natural population with the results of forward stochastic simulations under several contexts of epistasis between the candidate loci for the drive. We compute the likelihood of different possible scenarios, in order to determine which configuration is most consistent with the data. Our results highlight that fine scale analyses of well-chosen candidate genomic regions provide information-rich data that can be used to investigate the genotype-phenotype-fitness map, which can hardly be studied in genome-wide analyses. We also emphasize that initial conditions and time of observation (here, time after the interruption of a partial selective sweep) are crucial parameters in the interpretation of real data, while these are often overlooked in theoretical studies.

  11. 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.

  12. 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.

  13. Drug Abuse Patterns, Personality Characteristics, and Relationships with Sex, Race, and Sensation Seeking.

    Science.gov (United States)

    Sutker, Patricia B.; And Others

    1978-01-01

    Examined interrelationships among sex, race, drug-use patterns, and personality variables in chronic users of illicit drugs. Blacks were characterized by lower levels of sensation seeking, less psychopathology, use of fewer drug categories, and later drug use than Whites. Use and personality patterns among women differed little from men.…

  14. 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....

  15. 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...

  16. 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

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

    Directory of Open Access Journals (Sweden)

    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

  18. 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,

  19. 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

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

    Science.gov (United States)

    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…

  1. 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

  2. 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

  3. 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

  4. 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

  5. The human operational sex ratio: effects of marriage, concealed ovulation, and menopause on mate competition.

    Science.gov (United States)

    Marlowe, Frank W; Berbesque, J Colette

    2012-12-01

    Among mammals, male-male competition for sexual access to females frequently involves fighting. Larger body size gives males an advantage in fighting, which explains why males tend to be larger than females in many species, including anthropoid primates. Mitani et al. derived a formula to measure the operational sex ratio (OSR) to reflect the degree of male-male competition using the number of reproductively available males to females who are cycling and capable of conceiving. The OSR should predict the degree of sexual dimorphism in body mass-at least if male-male competition involves much fighting or threatening. Here, we use hunter-gatherer demographic data and the Mitani et al. formula to calculate the human OSR. We show that humans have a much lower degree of body mass sexual dimorphism than is predicted by our OSR. We suggest this is because human competition rarely involves fighting. In human hunter-gatherer societies, differences in the ages of marriage have an impact on competition in that the age of males at first marriage is younger when there is a lower percentage of married men with two or more wives, and older when there is a higher percentage of married men with two or more wives. We discuss the implications of this for females, along with the effects of two key life history traits that influence the OSR, concealed ovulation and menopause. While menopause decreases the number of reproductively available females to males and thus increases male-male competition, concealed ovulation decreases male-male competition. Finally, we discuss the importance of mostly monogamous mate bonds in human evolution. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. CHANGES IN SEX RATIO AT BIRTH IN CHINA: A DECOMPOSITION BY BIRTH ORDER.

    Science.gov (United States)

    Jiang, Quanbao; Yu, Qun; Yang, Shucai; Sánchez-Barricarte, Jesús J

    2017-11-01

    The long-term high sex ratio at birth (SRB) is a serious issue in China. In this study, changes in SRB were decomposed into variations in SRB by birth order and compositional changes in female births by birth order. With SRB data from China's surveys and censuses, and SRB data from South Korea's vital registration and censuses from 1980-2015, the trend and decomposition results in SRB were compared between China and South Korea, and the decomposition results for urban and rural SRBs, and for provinces, are presented. In both China and South Korea the rise in the SRB was driven by a rise in the SRB at all birth orders, which was only partly counteracted by the change in the distribution of births by order. The overall rise in the SRB ended when there was a decline in the SRB at second birth or above in South Korea. In China the total effect of variations in SRB of all birth orders increased more for the rural population than for the urban population before 2000, resulting in a higher total SRB for rural than urban population. After 2000, the total effect of variations in SRB of all birth orders lowered the total SRB for the rural population, whereas the effect of compositional change increased the total SRB, leading to a very slight rise in the total SRB for the rural population. At the province level, there was no spatial autocorrelation for the changes in total SRB by province, the total effect of variations in SRB of all birth orders or the effect of compositional change. The effect of variations in SRB by birth order accounted for the majority of changes in total SRB in most provinces.

  7. Superparasitism Drives Heritable Symbiont Epidemiology and Host Sex Ratio in a Wasp.

    Directory of Open Access Journals (Sweden)

    Steven R Parratt

    2016-06-01

    Full Text Available Heritable microbial symbionts have profound impacts upon the biology of their arthropod hosts. Whilst our current understanding of the dynamics of these symbionts is typically cast within a framework of vertical transmission only, horizontal transmission has been observed in a number of cases. For instance, several symbionts can transmit horizontally when their parasitoid hosts share oviposition patches with uninfected conspecifics, a phenomenon called superparasitism. Despite this, horizontal transmission, and the host contact structures that facilitates it, have not been considered in heritable symbiont epidemiology. Here, we tested for the importance of host contact, and resulting horizontal transmission, for the epidemiology of a male-killing heritable symbiont (Arsenophonus nasoniae in parasitoid wasp hosts. We observed that host contact through superparasitism is necessary for this symbiont's spread in populations of its primary host Nasonia vitripennis, such that when superparasitism rates are high, A. nasoniae almost reaches fixation, causes highly female biased population sex ratios and consequently causes local host extinction. We further tested if natural interspecific variation in superparasitism behaviours predicted symbiont dynamics among parasitoid species. We found that A. nasoniae was maintained in laboratory populations of a closely related set of Nasonia species, but declined in other, more distantly related pteromalid hosts. The natural proclivity of a species to superparasitise was the primary factor determining symbiont persistence. Our results thus indicate that host contact behaviour is a key factor for heritable microbe dynamics when horizontal transmission is possible, and that 'reproductive parasite' phenotypes, such as male-killing, may be of secondary importance in the dynamics of such symbiont infections.

  8. 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.

  9. Sex differences in patterns of genital sexual arousal: measurement artifacts or true phenomena?

    Science.gov (United States)

    Suschinsky, Kelly D; Lalumière, Martin L; Chivers, Meredith L

    2009-08-01

    Sex differences in patterns of sexual arousal have been reported recently. Men's genital arousal is typically more category-specific than women's, such that men experience their greatest genital arousal to stimuli depicting their preferred sex partners whereas women experience significant genital arousal to stimuli depicting both their preferred and non-preferred sex partners. In addition, men's genital and subjective sexual arousal patterns are more concordant than women's: The correlation between genital and subjective sexual arousal is much larger in men than in women. These sex differences could be due to low response-specificity in the measurement of genital arousal in women. The most commonly used measure of female sexual arousal, vaginal photoplethysmography, has not been fully validated and may not measure sexual arousal specifically. A total of 20 men and 20 women were presented with various sexual and non-sexual emotionally laden short film clips while their genital and subjective sexual arousal were measured. Results suggest that vaginal photoplethysmography is a measure of sexual arousal exclusively. Women's genital responses were highest during sexual stimuli and absent during all non-sexual stimuli. Sex differences in degree of category-specificity and concordance were replicated: Men's genital responses were more category-specific than women's and men's genital and subjective sexual arousal were more strongly correlated than women's. The results from the current study support the continued use of vaginal photoplethysmography in investigating sex differences in patterns of sexual arousal.

  10. Associating sex-biased and seasonal behaviour with contact patterns and transmission risk in Gopherus agassizii

    Science.gov (United States)

    Aiello, Christina M.; Esque, Todd; Nussear, K. E.; Emblidge, P. G.; Hudson, P. J.

    2018-01-01

    Interactions between wildlife hosts act as transmission routes for directly transmitted pathogens and vary in ways that affect transmission efficiency. Identifying drivers of contact variation can allow both contact inference and estimation of transmission dynamics despite limited data. In desert tortoises, mating strategy, burrow use and seasonal change influence numerous behaviours and likely shape contact patterns. In this study, we ask to what extent tortoise contact behaviour varies between sexes and seasons, and whether space or burrow-use data can be used to infer contact characteristics consistent with those recorded by proximity loggers. We identified sex and season-biased contact behaviour in both wild and captive populations indicative of female-female avoidance and seasonal male mate-seeking behaviour. Space and burrow-use patterns were informative, but did not always predict the extent of sex or seasonal biases on contact. We discuss the implications these findings have for transmission patterns and disease mitigation in tortoise populations.

  11. 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

  12. Allergen Sensitization Pattern by Sex: A Cluster Analysis in Korea.

    Science.gov (United States)

    Ohn, Jungyoon; Paik, Seung Hwan; Doh, Eun Jin; Park, Hyun-Sun; Yoon, Hyun-Sun; Cho, Soyun

    2017-12-01

    Allergens tend to sensitize simultaneously. Etiology of this phenomenon has been suggested to be allergen cross-reactivity or concurrent exposure. However, little is known about specific allergen sensitization patterns. To investigate the allergen sensitization characteristics according to gender. Multiple allergen simultaneous test (MAST) is widely used as a screening tool for detecting allergen sensitization in dermatologic clinics. We retrospectively reviewed the medical records of patients with MAST results between 2008 and 2014 in our Department of Dermatology. A cluster analysis was performed to elucidate the allergen-specific immunoglobulin (Ig)E cluster pattern. The results of MAST (39 allergen-specific IgEs) from 4,360 cases were analyzed. By cluster analysis, 39items were grouped into 8 clusters. Each cluster had characteristic features. When compared with female, the male group tended to be sensitized more frequently to all tested allergens, except for fungus allergens cluster. The cluster and comparative analysis results demonstrate that the allergen sensitization is clustered, manifesting allergen similarity or co-exposure. Only the fungus cluster allergens tend to sensitize female group more frequently than male group.

  13. Divorce, Abortion and Children's Sex Ratio: The Impact of Divorce Reform in China

    OpenAIRE

    Sun, Ang; Zhao, Yaohui

    2014-01-01

    This paper explores how the relative circumstances of men and women following marital dissolution affect sex-selection behavior within marriages. China's 2001 divorce reform liberalized divorce in favor of women and secured women's property rights after separation. We use this improvement in women's bargaining power in marriage for a regression discontinuity analysis of the demand for sex-selective abortions. We show that the increase in women's bargaining power reduces the propensity to have...

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

    Directory of Open Access Journals (Sweden)

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. Birth Order and Sibling Sex Ratio in a Population with High Fertility: Are Turkish Male to Female Transsexuals Different?

    Science.gov (United States)

    Bozkurt, Ali; Bozkurt, Ozlem Hekim; Sonmez, Ipek

    2015-07-01

    Western studies have consistently found that androphilic (sexually attracted to men) male-to-female transsexuals have a later birth order and a relative excess of brothers compared with appropriate control participants. However, non-Western studies on birth order and sibling sex ratio in androphilic males (transsexual or non-transsexual) are rare. The objective of the study was to test the hypothesis that androphilic male-to-female transsexuals have a late birth order and a relative excess of brothers in a non-Western culture with a higher fertility rate. The participants were 60 androphilic male-to-female transsexuals and 61 male heterosexual controls. The transsexual participants had significantly more older brothers than the control participants, but the groups did not differ in their numbers of older sisters, younger brothers, or younger sisters. The foregoing pattern is usually referred to as the "fraternal birth order effect." Slater's and Berglin's Indexes both showed that the mean birth order of the control participants was very close to that expected from a random sample drawn from a demographically stable population whereas the mean birth order of the transsexual participants was later. A measure of sibship composition, brothers/all siblings, showed that the transsexual group had a higher proportion of male siblings compared with the control group. In conclusion, the present study found that Turkish androphilic male-to-female transsexuals show the same high fraternal birth order that has been found in comparable androphilic samples in Western Europe, North America, and the South Pacific, which suggests a common underlying biological causal mechanism.

  20. Changing trend? Sex ratios of children born to Indian immigrants in Norway revisited.

    Science.gov (United States)

    Tønnessen, Marianne; Aalandslid, Vebjørn; Skjerpen, Terje

    2013-09-05

    In some Western countries, a disturbingly low share of girls has been observed among new-borns from Indian immigrants. Also in Norway, a previous study based on figures from 1969-2005 showed a high percentage of boys among children of Indian origin living in Norway, when the birth was of higher order (third birth or later). This was suggested to reflect a practice of sex-selective abortions in the Indian immigrant population. In this article we have seen whether extended time series for the period 2006-2012 give further support to this claim. Based on data from the Norwegian Central Population Register we used observations for the sex of all live births in Norway for the period 1969-2012 where the mother was born in India. The percentage of boys was calculated for each birth order, during four sub periods. Utilising a binomial probability model we tested whether the observed sex differences among Indian-born women were significantly different from sex differences among all births. Contrary to findings from earlier periods and other Western countries, we found that Indian-born women in Norway gave birth to more girls than boys of higher order in the period 2006-2012. This is somewhat surprising, since sex selection is usually expected to be stronger if the mother already has two or more children. The extended time series do not suggest a prevalence of sex selective abortions among Indian-born women in Norway. We discuss whether the change from a majority of boys to a majority of girls in higher order could be explained by new waves of immigrant women, by new preferences among long-residing immigrant women in Norway - or by mere coincidence.

  1. 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)

  2. 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.

  3. 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....

  4. 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.

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

    Science.gov (United States)

    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.

  6. Sex-ratio control erodes sexual selection, revealing evolutionary feedback from adaptive plasticity

    NARCIS (Netherlands)

    Fawcett, Tim W.; Kuijper, Bram; Weissing, Franz J.; Pen, Ido

    2011-01-01

    Female choice is a powerful selective force, driving the elaboration of conspicuous male ornaments. This process of sexual selection has profound implications for many life-history decisions, including sex allocation. For example, females with attractive partners should produce more sons, because

  7. Effect of time of artificial insemination on embryo sex ratio in dairy cattle

    NARCIS (Netherlands)

    Roelofs, J.B.; Bouwman, E.B.; Pedersen, H.G.; Riestra Rasmussen, Z.; Soede, N.M.; Thomsen, P.D.; Kemp, B.

    2006-01-01

    The objective of the present study was to examine whether different intervals between insemination and ovulation have an influence on the sex of seven-day-old embryos in dairy cattle. Cows were inseminated once with semen of one of two bulls of proven fertility between 36 h before ovulation and 12 h

  8. 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 ...

  9. 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.

  10. Using RNA-seq to determine patterns of sex-bias in gene expression in the brain of the sex-role reversed Gulf Pipefish (Syngnathus scovelli).

    Science.gov (United States)

    Beal, Andria P; Martin, F Douglas; Hale, Matthew C

    2018-02-01

    Sex-bias in gene expression is a widespread mechanism for controlling the development of phenotypes that differ between males and females. Most studies on sex-bias in gene expression have focused on species that exhibit traditional sex-roles (male-male competition and female parental care). By contrast the Syngnathid fishes (sea horses, pipefish, and sea dragons) are a group of organisms where many species exhibit male brooding and sex-role reversal (female-female competition for mates and paternal parental care), and little is known about how patterns of sex-bias in gene expression vary in species with sex-role reversal. Here we utilize RNA-seq technology to investigate patterns of sex-bias in gene expression in the brain tissue of the Gulf Pipefish (Syngnathus scovelli) a species that exhibits sex-role reversal. Gene expression analysis identified 73 sex-biased genes, 26 genes upregulated in females and 47 genes upregulated in males. Gene ontology analysis found 52 terms enriched for the sex-biased genes in a wide range of pathways suggesting that multiple functions and processes differ between the sexes. We focused on two areas of interest: sex steroids/hormones and circadian rhythms, both of which exhibited sex-bias in gene expression, and are known to influence sexual development in other species. Lastly, the work presented herein contributes to a growing body of genome data available for the Syngnathids, increasing our knowledge on patterns of gene expression in these unusual fishes. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Gender perceptions predict sex differences in growth patterns of indigenous Guatemalan infants and young children.

    Science.gov (United States)

    Tumilowicz, Alison; Habicht, Jean-Pierre; Pelto, Gretel; Pelletier, David L

    2015-11-01

    Nearly one-half of Guatemalan children experience growth faltering, more so in indigenous than in nonindigenous children. On the basis of ethnographic interviews in Totonicapán, Guatemala, which revealed differences in maternal perceptions about food needs in infant girls and boys, we predicted a cumulative sex difference in favor of girls that occurred at ∼6 mo of age and diminished markedly thereafter. We examined whether the predicted differences in age-sex patterns were observed in the village, replicated the examination nationally for indigenous children, and examined whether the pattern in nonindigenous children was different. Ethnographic interviews (n = 24) in an indigenous village were conducted. Anthropometric measurements of the village children aged 0-35 mo (n = 119) were obtained. National-level growth patterns were analyzed for indigenous (n = 969) and nonindigenous (n = 1374) children aged 0-35 mo with the use of Demographic and Health Survey (DHS) data. Mothers reported that, compared with female infants, male infants were hungrier, were not as satisfied with breastfeeding alone, and required earlier complementary feeding. An anthropometric analysis confirmed the prediction of healthier growth in indigenous girls than in indigenous boys throughout the first year of life, which resulted in a 2.98-cm height-for-age difference (HAD) between sexes in the village and a 1.61-cm HAD (P differences diminished in the second year of life (P differences in the HAD that first favor girls and then favor boys in the indigenous growth patterns are due to feeding patterns on the basis of gendered cultural perceptions. Circumstances that result in differential sex growth patterns need to be elucidated, in particular the favorable growth in girls in the first year of life. © 2015 American Society for Nutrition.

  12. Diversity of palatal rugae patterns and their reliability in sex discrimination in a South Indian population

    Directory of Open Access Journals (Sweden)

    Sai Madhavi Nallamilli

    2015-01-01

    Full Text Available Introduction and Aims: Array of palatal rugae in the realm of forensic odontology has been constantly explored owing to their individual uniqueness and resistance to postmortem procedures, while their scope in sex determination and racial profiling remains understated. In this context, the present study aimed to record the diversity of palatal rugae patterns in a South Indian population. Materials and Methods: A descriptive cross-sectional study was conducted among people who reported to the outpatient department of a dental institution. Sample comprised a total of 200 subjects divided into two groups of 100 each, based upon gender. Impressions of anterior maxilla were made of all the study subjects and casts obtained subsequently. Outline of palatal rugae pattern was traced on these models and the data computed. Z test and unpaired t-test were used for statistical analysis and the probability value calculated. In addition, logistic regression analysis was performed to estimate the accuracy of sex allocation. Results: The shape of rugae exhibited highly significant sex difference in the curved type, which was found to be higher in males, and in the wavy type which was higher in females, enabling sex differentiation using palatal rugae patterns. Logistic regression analysis predicted high power of sex allocation for males rather than females in the study population. Conclusion: This study highlighted the uniqueness and greater sex discrimination potential of curved shape of palatal rugae in categorizing males of South Indian population, substantiating their use in the identification of deceased, by relating the antemortem and postmortem dental records.

  13. 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

  14. Spatiotemporal Patterns in a Ratio-Dependent Food Chain Model with Reaction-Diffusion

    Directory of Open Access Journals (Sweden)

    Lei Zhang

    2014-01-01

    Full Text Available Predator-prey models describe biological phenomena of pursuit-evasion interaction. And this interaction exists widely in the world for the necessary energy supplement of species. In this paper, we have investigated a ratio-dependent spatially extended food chain model. Based on the bifurcation analysis (Hopf and Turing, we give the spatial pattern formation via numerical simulation, that is, the evolution process of the system near the coexistence equilibrium point (u2*,v2*,w2*, and find that the model dynamics exhibits complex pattern replication. For fixed parameters, on increasing the control parameter c1, the sequence “holes → holes-stripe mixtures → stripes → spots-stripe mixtures → spots” pattern is observed. And in the case of pure Hopf instability, the model exhibits chaotic wave pattern replication. Furthermore, we consider the pattern formation in the case of which the top predator is extinct, that is, the evolution process of the system near the equilibrium point (u1*,v1*,0, and find that the model dynamics exhibits stripes-spots pattern replication. Our results show that reaction-diffusion model is an appropriate tool for investigating fundamental mechanism of complex spatiotemporal dynamics. It will be useful for studying the dynamic complexity of ecosystems.

  15. Shading Ratio Impact on Photovoltaic Modules and Correlation with Shading Patterns

    Directory of Open Access Journals (Sweden)

    Alonso Gutiérrez Galeano

    2018-04-01

    Full Text Available This paper presents the study of a simplified approach to model and analyze the performance of partially shaded photovoltaic modules using the shading ratio. This approach integrates the characteristics of shaded area and shadow opacity into the photovoltaic cell model. The studied methodology is intended to improve the description of shaded photovoltaic systems by specifying an experimental procedure to quantify the shadow impact. Furthermore, with the help of image processing, the analysis of the shading ratio provides a set of rules useful for predicting the current–voltage behavior and the maximum power points of shaded photovoltaic modules. This correlation of the shading ratio and shading patterns can contribute to the supervision of actual photovoltaic installations. The experimental results validate the proposed approach in monocrystalline and polycrystalline technologies of solar panels.

  16. A study of distribution, sex differences and stability of lip print patterns in an Indian population.

    Science.gov (United States)

    Kapoor, Neeti; Badiye, Ashish

    2017-09-01

    Lip prints are very useful in forensic investigations. The objective of this study is to determine predominant lip print pattern found among a central Indian population, to evaluate whether any sex difference exists and to study the permanence of the pattern over a 6 month duration. This study included 200 healthy adult subjects comprising of 100 males and 100 females in the age group of 18-25 years. A convenient and easier method of data collection i.e., digital photography was used instead of the traditional lipstick methods. Lip prints were then divided into four quadrants and recognized as per Suzuki and Tsuchihashi's classification. Type I (30.63%) was found to be most predominant overall in the Marathi population. Type I (29.75%) and Type III (35.75%) were found most prevalent in males and females respectively. Applying the Chi-Square test, statistically significant differences ( p  < 0.05) were observed between male and female lip print patterns in each of the quadrants individually and all quadrants taken together. The lip print patterns remained stable over a period of six-months. Being stable and with significant sex differences, lip prints can be effectively used as an important tool in forensic investigations for individualization as well as identification of sex of the donor, thus, narrowing down the scope of investigation to almost half.

  17. 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.

  18. Exposure to persistent organic pollutants and sperm sex chromosome ratio in men from the Faroe Islands

    DEFF Research Database (Denmark)

    Kvist, L; Giwercman, A; Weihe, P

    2014-01-01

    People in the Arctic as well as fishermen on the polluted Swedish east coast are highly exposed to persistent organic pollutants (POPs). These compounds have been shown to affect the sperm Y:X chromosome ratio. In present study, the aim was to investigate whether polychlorinated biphenyl (PCB......,p'-DDE and ΣPCB correlated significantly (r=0.927, pboth Inuit and Swedish fishermen (0.512 for both......). In conclusion, Faroese men presented with lower Y:X ratio than Greenland Inuit and Swedish fishermen. Although no direct health effects are expected due to the lower Faroese Y:X ratio, it could be indicative of adverse effects on the reproductive system....

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

    Directory of Open Access Journals (Sweden)

    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

  20. Smoking and increased risk of multiple sclerosis: parallel trends in the sex ratio reinforce the evidence

    DEFF Research Database (Denmark)

    Palacios, Natalia; Alonso, Alvaro; Brønnum-Hansen, Henrik

    2011-01-01

    Smoking behavior in industrialized nations has changed markedly over the second half of the 20th century, with diverging patterns in male and female smoking rates. We examined whether the female/male incidence of multiple sclerosis (MS) changed concomitantly with smoking, as would be expected if ...

  1. Spatial pattern of Baccharis platypoda shrub as determined by sex and life stages

    Science.gov (United States)

    Fonseca, Darliana da Costa; de Oliveira, Marcio Leles Romarco; Pereira, Israel Marinho; Gonzaga, Anne Priscila Dias; de Moura, Cristiane Coelho; Machado, Evandro Luiz Mendonça

    2017-11-01

    Spatial patterns of dioecious species can be determined by their nutritional requirements and intraspecific competition, apart from being a response to environmental heterogeneity. The aim of the study was to evaluate the spatial pattern of populations of a dioecious shrub reporting to sex and reproductive stage patterns of individuals. Sampling was carried out in three areas located in the meridional portion of Serra do Espinhaço, where in individuals of the studied species were mapped. The spatial pattern was determined through O-ring analysis and Ripley's K-function and the distribution of individuals' frequencies was verified through x2 test. Populations in two areas showed an aggregate spatial pattern tending towards random or uniform according to the observed scale. Male and female adults presented an aggregate pattern at smaller scales, while random and uniform patterns were verified above 20 m for individuals of both sexes of the areas A2 and A3. Young individuals presented an aggregate pattern in all areas and spatial independence in relation to adult individuals, especially female plants. The interactions between individuals of both genders presented spatial independence with respect to spatial distribution. Baccharis platypoda showed characteristics in accordance with the spatial distribution of savannic and dioecious species, whereas the population was aggregated tending towards random at greater spatial scales. Young individuals showed an aggregated pattern at different scales compared to adults, without positive association between them. Female and male adult individuals presented similar characteristics, confirming that adult individuals at greater scales are randomly distributed despite their distinct preferences for environments with moisture variation.

  2. Digit ratio (2D:4D) and social integration: an effect of prenatal sex hormones

    Czech Academy of Sciences Publication Activity Database

    Kovářík, Jaromír; Brañas-Garza, P.; Davidson, M. W.; Haim, D. A.; Carcelli, S.; Fowler, J. H.

    2017-01-01

    Roč. 5, č. 4 (2017), s. 476-489 ISSN 2050-1242 R&D Projects: GA ČR(CZ) GA14-22044S Institutional support: RVO:67985998 Keywords : social networks * digit ratio * prenatal and rogens Subject RIV: AH - Economics OBOR OECD: Applied Economics, Econometrics

  3. Differences in Patterns of Reproductive Allocation between the Sexes in Nicrophorus orbicollis.

    Directory of Open Access Journals (Sweden)

    Ashlee N Smith

    Full Text Available Organisms are selected to maximize lifetime reproductive success by balancing the costs of current reproduction with costs to future survival and fecundity. Males and females typically face different reproductive costs, which makes comparisons of their reproductive strategies difficult. Burying beetles provide a unique system that allows us to compare the costs of reproduction between the sexes because males and females are capable of raising offspring together or alone and carcass preparation and offspring care represent the majority of reproductive costs for both sexes. Because both sexes perform the same functions of carcass preparation and offspring care, we predict that they would experience similar costs and have similar life history patterns. In this study we assess the cost of reproduction in male Nicrophorus orbicollis and compare to patterns observed in females. We compare the reproductive strategies of single males and females that provided pre- and post-hatching parental care. There is a cost to reproduction for both males and females, but the sexes respond to these costs differently. Females match brood size with carcass size, and thus maximize the lifetime number of offspring on a given size carcass. Males cull proportionately more offspring on all carcass sizes, and thus have a lower lifetime number of offspring compared to females. Females exhibit an adaptive reproductive strategy based on resource availability, but male reproductive strategies are not adaptive in relation to resource availability.

  4. Differences in Patterns of Reproductive Allocation between the Sexes in Nicrophorus orbicollis.

    Science.gov (United States)

    Smith, Ashlee N; Creighton, J Curtis; Belk, Mark C

    2015-01-01

    Organisms are selected to maximize lifetime reproductive success by balancing the costs of current reproduction with costs to future survival and fecundity. Males and females typically face different reproductive costs, which makes comparisons of their reproductive strategies difficult. Burying beetles provide a unique system that allows us to compare the costs of reproduction between the sexes because males and females are capable of raising offspring together or alone and carcass preparation and offspring care represent the majority of reproductive costs for both sexes. Because both sexes perform the same functions of carcass preparation and offspring care, we predict that they would experience similar costs and have similar life history patterns. In this study we assess the cost of reproduction in male Nicrophorus orbicollis and compare to patterns observed in females. We compare the reproductive strategies of single males and females that provided pre- and post-hatching parental care. There is a cost to reproduction for both males and females, but the sexes respond to these costs differently. Females match brood size with carcass size, and thus maximize the lifetime number of offspring on a given size carcass. Males cull proportionately more offspring on all carcass sizes, and thus have a lower lifetime number of offspring compared to females. Females exhibit an adaptive reproductive strategy based on resource availability, but male reproductive strategies are not adaptive in relation to resource availability.

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

    Directory of Open Access Journals (Sweden)

    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

  6. The effects of cavity length on nest size, sex ratio and mortality of Centris (Heterocentris) analis (Hymenoptera, Apidae, Centridini)

    OpenAIRE

    Alonso , Juliana; Silva , Janaina; Garófalo , Carlos

    2012-01-01

    International audience; This study investigated the effects of different cavity lengths in trap-nests on the number of cells constructed per nest, sex ratio and mortality of offspring of Centris analis at three sites in Ribeirão Preto, São Paulo, Brazil. Cavity length did not affect the occupation rates of the trap-nests, with the exception of a preference for the shortest trap-nests found at one site. The number of cells per nest increased with trap-nest length. Cavity length affected neithe...

  7. The dynamics of male brooding, mating patterns, and sex roles in pipefishes and seahorses (family Syngnathidae).

    Science.gov (United States)

    Wilson, Anthony B; Ahnesjö, Ingrid; Vincent, Amanda C J; Meyer, Axel

    2003-06-01

    Modern theory predicts that relative parental investment of the sexes in their young is a key factor responsible for sexual selection. Seahorses and pipefishes (family Syngnathidae) are extraordinary among fishes in their remarkable adaptations for paternal care and frequent occurrences of sex-role reversals (i.e., female-female competition for mates), offering exceptional opportunities to test predictions of sexual selection theory. During mating, the female transfers eggs into or onto specialized egg-brooding structures that are located on either the male's abdomen or its tail, where they are osmoregulated, aerated, and nourished by specially adapted structures. All syngnathid males exhibit this form of parental care but the brooding structures vary, ranging from the simple ventral gluing areas of some pipefishes to the completely enclosed pouches found in seahorses. We present a molecular phylogeny that indicates that the diversification of pouch types is positively correlated with the major evolutionary radiation of the group, suggesting that this extreme development and diversification of paternal care may have been an important evolutionary innovation of the Syngnathidae. Based on recent studies that show that the complexity of brooding structures reflects the degree of paternal investment in several syngnathid species, we predicted sex-role reversals to be more common among species with more complex brooding structures. In contrast to this prediction, however, both parsimony- and likelihood-based reconstructions of the evolution of sex-role reversal in pipefishes and seahorses suggest multiple shifts in sex roles in the group, independent from the degree of brood pouch development. At the same time, our data demonstrate that sex-role reversal is positively associated with polygamous mating patterns, whereas most nonreversed species mate monogamously, suggesting that selection for polygamy or monogamy in pipefishes and seahorses may strongly influence sex

  8. Seasonal changes in the gonadossomatic index, allometric condition factor and sex ratio of an auchenipterid catfish from eastern Amazonia

    Directory of Open Access Journals (Sweden)

    Tiago Magalhães da Silva Freitas

    2011-01-01

    Full Text Available The aim of the present study was to evaluate the seasonal pattern of the gonadosomatic index (GSI, condition factor (K, and sex ratio in the catfish Auchenipterichthys longimanus (Siluriformes: Auchenipteridae as an approach to identify its reproductive period. A total of 589 A. longimanus specimens (251 males and 338 females were captured in the rivers of the Caxiuanã National Forest, in the Brazilian state of Pará, between July, 2008 and July, 2009. Among the male specimens, 171 were classified as adults and 80 as juveniles, while there were 249 adults and 89 juvenile females. Using a sinusoidal equation, analysis of the GSI revealed a reproductive asynchrony between the genders, with males attaining their highest GSI values in January, while females peaked in March. For males, the sinusoidal regression for GSI values was significant only when used the complete data set (P=0.001, wears no trend was identified for bimonthly means (P=0.136. For females, by contrast, significant values were obtained for both the complete data set (P=0.012 and bimonthly GSI means (P=0.026. For the condition factor, the sinusoidal equation returned significant seasonal variation in both raw data (P=0.02 and with mean values (P=0.00 for males, but only with raw data for females (P=0.04, which appears to reflect variation in the energy budget between genders. With regard to the sex ratio, more reproductive females were captured than males in January and March, 2009, which suggests a pattern of segregation related to the reproductive process. These parameters are fundamental to the assessment, protection, and management of natural fish stocks, as well as providing guidelines for the development of conservation strategies.O objetivo deste estudo foi avaliar alterações sazonais no índice gonadossomático (IGS%, fator de condição (K e proporção sexual, a fim de determinar o período de atividade reprodutiva do bagre Auchenipterichthys longimanus (Siluriformes

  9. Digit ratio (2D:4D) and social integration: an effect of prenatal sex hormones

    OpenAIRE

    Kovářík, Jaromír; Branas-Garza, Pablo; Davidson, Michael W.; Haim, Dotan A.; Carcelli, Shannon; Fowler, James H.

    2017-01-01

    The position people occupy in their social and professional networks is related to their social status and has strong effects on their access to social resources. While attainment of particular positions is driven by behavioral traits, many biological factors predispose individuals to certain behaviors and motivations. Prior work on exposure to fetal androgens (measured by second-to-fourth digit ratio, 2D:4D) shows that it correlates with behaviors and traits related to social status, which m...

  10. Association of UV radiation with multiple sclerosis prevalence and sex ratio in France.

    Science.gov (United States)

    Orton, S-M; Wald, L; Confavreux, C; Vukusic, S; Krohn, J P; Ramagopalan, S V; Herrera, B M; Sadovnick, A D; Ebers, G C

    2011-02-01

    French farmers and their families constitute an informative population to study multiple sclerosis (MS) prevalence and related epidemiology. We carried out an ecological study to evaluate the association of MS prevalence and ultraviolet (UV) radiation, a candidate climatologic risk factor. Mean annual and winter (December-March) UVB irradiation values were systematically compared to MS prevalence rates in corresponding regions of France. UVB data were obtained from the solar radiation database (SoDa) service and prevalence rates from previously published data on 2,667 MS cases registered with the national farmer health insurance system, Mutualité Sociale Agricole (MSA). Pearson correlation was used to examine the relationship of annual and winter UVB values with MS prevalence. Male and female prevalence were also analyzed separately. Linear regression was used to test for interaction of annual and winter UVB with sex in predicting MS prevalence. There was a strong association between MS prevalence and annual mean UVB irradiation (r = -0.80, p role for gender-specific effects of UVB exposure.

  11. Normalized burn ratios link fire severity with patterns of avian occurrence

    Science.gov (United States)

    Rose, Eli T.; Simons, Theodore R.; Klein, Rob; McKerrow, Alexa

    2016-01-01

    ContextRemotely sensed differenced normalized burn ratios (DNBR) provide an index of fire severity across the footprint of a fire. We asked whether this index was useful for explaining patterns of bird occurrence within fire adapted xeric pine-oak forests of the southern Appalachian Mountains.ObjectivesWe evaluated the use of DNBR indices for linking ecosystem process with patterns of bird occurrence. We compared field-based and remotely sensed fire severity indices and used each to develop occupancy models for six bird species to identify patterns of bird occurrence following fire.MethodsWe identified and sampled 228 points within fires that recently burned within Great Smoky Mountains National Park. We performed avian point counts and field-assessed fire severity at each bird census point. We also used Landsat™ imagery acquired before and after each fire to quantify fire severity using DNBR. We used non-parametric methods to quantify agreement between fire severity indices, and evaluated single season occupancy models incorporating fire severity summarized at different spatial scales.ResultsAgreement between field-derived and remotely sensed measures of fire severity was influenced by vegetation type. Although occurrence models using field-derived indices of fire severity outperformed those using DNBR, summarizing DNBR at multiple spatial scales provided additional insights into patterns of occurrence associated with different sized patches of high severity fire.ConclusionsDNBR is useful for linking the effects of fire severity to patterns of bird occurrence, and informing how high severity fire shapes patterns of bird species occurrence on the landscape.

  12. Female biased sex-ratio in Schistosoma mansoni after exposure to an allopatric intermediate host strain of Biomphalaria glabrata.

    Science.gov (United States)

    Lepesant, Julie M J; Boissier, Jérôme; Climent, Déborah; Cosseau, Céline; Grunau, Christoph

    2013-10-01

    For parasites that require multiple hosts to complete their development, the interaction with the intermediate host may have an impact on parasite transmission and development in the definitive host. The human parasite Schistosoma mansoni needs two different hosts to complete its life cycle: the freshwater snail Biomphalaria glabrata (in South America) as intermediate host and a human or rodents as final host. To investigate the influence of the host environment on life history traits in the absence of selection, we performed experimental infections of two B. glabrata strains of different geographic origin with the same clonal population of S. mansoni. One B. glabrata strain is the sympatric host and the other one the allopatric host. We measured prevalence in the snail, the cercarial infectivity, sex-ratio, immunopathology in the final host and microsatellite frequencies of individual larvae in three successive generations. We show that, even if the parasite population is clonal based on neutral markers, S. mansoni keeps the capacity of generating phenotypic plasticity and/or variability for different life history traits when confront to an unusual environment, in this study the intermediate host. The most dramatic change was observed in sex-ratio: in average 1.7 times more female cercariae were produced when the parasite developed in an allopatric intermediate host. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. 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.

  14. Sex ratio, poverty, and concurrent partnerships among men and women in the United States: a multilevel analysis.

    Science.gov (United States)

    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.

  15. 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.)

  16. Depleted uranium induces sex- and tissue-specific methylation patterns in adult zebrafish

    International Nuclear Information System (INIS)

    Gombeau, Kewin; Pereira, Sandrine; Ravanat, Jean-Luc; Camilleri, Virginie; Cavalie, Isabelle; Bourdineaud, Jean-Paul; Adam-Guillermin, Christelle

    2016-01-01

    We examined the effects of chronic exposure to different concentrations (2 and 20 μg L"−"1) of environmentally relevant waterborne depleted uranium (DU) on the DNA methylation patterns both at HpaII restriction sites (5′-CCGG-3′) and across the whole genome in the zebrafish brain, gonads, and eyes. We first identified sex-dependent differences in the methylation level of HpaII sites after exposure. In males, these effects were present as early as 7 days after exposure to 20 μg L"−"1 DU, and were even more pronounced in the brain, gonads, and eyes after 24 days. However, in females, hypomethylation was only observed in the gonads after exposure to 20 μg L"−"1 DU for 24 days. Sex-specific effects of DU were also apparent at the whole-genome level, because in males, exposure to 20 μg L"−"1 DU for 24 days resulted in cytosine hypermethylation in the brain and eyes and hypomethylation in the gonads. In contrast, in females, hypermethylation was observed in the brain after exposure to both concentrations of DU for 7 days. Based on our current knowledge of uranium toxicity, several hypotheses are proposed to explain these findings, including the involvement of oxidative stress, alteration of demethylation enzymes and the calcium signaling pathway. This study reports, for the first time, the sex- and tissue-specific epigenetic changes that occur in a nonhuman organism after exposure to environmentally relevant concentrations of uranium, which could induce transgenerational epigenetic effects. - Highlights: • This study demonstrates a sex-related effect of DU exposure on DNA methylation patterns. • Impacts on DNA methylation patterns revealed a tissue-specific effect of DU exposure. • The MS–AFLP and HPLC–MS/MS sensitively and complementarily demonstrated the responses to environmental concentrations of DU.

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

    Science.gov (United States)

    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 the circadian rhythm of the two sexes was not constant over time and changed during the light period. There was also an effect of density on locomotor activity, where males at intermediate densities showed higher activity. Further, the predictability of the locomotor activity, estimated as the degree of autocorrelation of the activity data, increased with the number of males present in the vials both with and without the presence of females. Overall, this study demonstrates that locomotor activity in M. domestica is affected by sex—ratio and density. Furthermore, the predictability of locomotor activity is affected by both sex—ratio, density, and circadian rhythm. These results add to our understanding of the behavioral interactions between houseflies and highlight the importance of these factors when designing behavioral experiments using M. domestica.

  18. 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

  19. 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

  20. Foot strike pattern in preschool children during running: sex and shod-unshod differences.

    Science.gov (United States)

    Latorre-Román, Pedro Á; Párraga-Montilla, Juan A; Guardia-Monteagudo, Ignacio; García-Pinillos, Felipe

    2018-04-01

    This study aims to determine the foot strike patterns (FSPs) and neutral support (no inversion [INV]/eversion [EVE] and no foot rotation) in preschool children, as well as to determine the influence of shod/unshod conditions and sex. A total of 1356 children aged 3-6 years (673 boys and 683 girls) participated in this study. A sagittal and frontal-plane video (240 Hz) was recorded using a high-speed camcorder to record the following variables: rearfoot strike (RFS), midfoot strike (MFS), forefoot strike (FFS), inversion/ eversion (INV/EVE) and foot rotation on initial contact. There were no between-sex significant differences in both shod and unshod conditions in RFS. In the unshod condition, there was a significant reduction (p < 0.001) of RFS prevalence in both boys (shod condition = 44.2% vs. 34.7% unshod condition) and girls (shod condition = 48.5% vs. 36.1% unshod condition). As for neutral support, there were no between-sex differences in both shod and unshod conditions or in the shod-unshod comparison. In preschool children, no between-sex differences were found in relation to prevalence of RFS and neutral support (no INV/EVE). Shod running alters FSP of running barefoot, producing a significant increase of RFS prevalence.

  1. SECULAR TRENDS AND LATITUDE GRADIENTS IN SEX RATIOS AT BIRTH IN THE FORMER SOVIET REPUBLICS

    Directory of Open Access Journals (Sweden)

    Victor Grech

    2013-01-01

    Full Text Available Background: The male-female ratio at birth (M/F: male births divided by total births, which is anticipated to approximate 0.515, has been shown to exhibit latitude gradients and secular trends. Methods: Annual national data for male and female live births for the 15 countries that comprise the former Soviet Union were obtained from the World Health Organisation for the period 1980–2009 (115,167,569 total live births and analysed with contingency tables. Spearman correlation was also carried out to compare percentage annual gross domestic product growth (GDP% – downloaded from the World Bank and M/F. In this context, GDP% is used as a measure for economic hardship or wellbeing within the populace. Results: There have been overall highly significant secular increases in M/F (p < 0.0001 in the countries and regions investigated. M/F is significantly lower in the three more northern regions (Russian Federation, Baltic States and Central Asia. M/F 0.51324, 0.51335-0.51314 than the two more southern regions (Southern Caucasus and Eastern Europe. M/F 0.51654, 0.51635-0.51672. There was a male excess of 113,818 live births.There was a significant positive correlation between GDP% and M/F for Armenia, Azerbaijan and Uzbekistan. There was a significant negative correlation in Estonia. Conclusion: Previous studies have shown that improving socioeconomic conditions increase M/F, and the converse has also been demonstrated. This is a potential influence in this geographical area since this region has relatively recently emerged from communist rule and experienced an overall economic upturn, but is only partially supported using GDP%. Another factor may be the selective termination of female pregnancies. The latitude gradient parallels that of neighbouring Europe but no theory has been put forward to convincingly explain this finding to date.

  2. 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.

    Directory of Open Access Journals (Sweden)

    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

  3. The effects of sex, sexual orientation, and digit ratio (2D:4D) on mental rotation performance.

    Science.gov (United States)

    Peters, Michael; Manning, John T; Reimers, Stian

    2007-04-01

    In spite of the reduced level of experimental control, this large scale study brought some clarity into the relation between mental rotation task (MRT) performance and a number of variables where contradictory associations had previously been reported in the literature. Clear sex differences in MRT were observed for a sample of 134,317 men and 120,783 women, with men outperforming women. There were also MRT differences as a function of sexual orientation: heterosexual men performed better than homosexual men and homosexual women performed better than heterosexual women. Although bisexual men performed better than homosexual men but less well than heterosexual men, no significant differences were observed between bisexual and homosexual women. MRT performance in both men and women peaked in the 20-30 year range, and declined significantly and markedly thereafter. Both men and women showed a significant negative correlation between left and right digit finger ratio and MRT scores, such that individuals with smaller digit ratios (relatively longer ring finger than index finger) performed better than individuals with larger digit ratios.

  4. Sex-specific sleep patterns among university students in Lebanon: impact on depression and academic performance.

    Science.gov (United States)

    Kabrita, Colette S; Hajjar-Muça, Theresa A

    2016-01-01

    Good sleep quality and quantity are fundamental to the maintenance of normal physiological processes. Changes in sleep patterns are commonly observed among young adults and are shown to impact neurocognitive, academic, and psychological well-being. Given the scarcity of sleep information about Lebanon and acknowledging the sex differences in various sleep dimensions, we conducted a study that aimed at assessing sex differences in sleep habits among university students in Lebanon in relation to psychoacademic status. A total of 540 students (50.6% females) completed a questionnaire that inquired about sociodemographics and evaluated sleep quality and depression using the Pittsburg Sleep Quality Index (PSQI) and Center for Epidemiological Studies Depression Scale (CES-D), respectively. The mean PSQI global score (6.57±3.49) indicated poor sleep, with no significant differences between men and women. The sleep/wake rhythm was delayed on weekends for both sexes. Females exhibited earlier bedtimes and rise times and longer sleep durations on both weekdays and weekends. However, unlike males females showed a greater phase delay in wake times than bedtimes on weekends (149 minutes vs 74 minutes, respectively). In all, 70.9% of females suffered from depressive symptoms, which was a significantly higher proportion compared with 58.5% of males (Pacademic performance of females was significantly better than that of males (2.8±0.61 vs 2.65±0.61, Psleep duration (r=-0.221, Psleep timing, such as bedtime/rise time and nocturnal sleep duration, rather than sleep quality exist among Lebanese university students. Sex-specific sleep patterns have differential impact on psychological and academic well-being.

  5. Impacts of temperature and crowding on sex ratio, fecundity and Wolbachia infection intensity in the copepod, Mesocyclops thermocyclopoides.

    Science.gov (United States)

    Wiwatanaratanabutr, Itsanun; Grandjean, Frederic

    2016-11-01

    Wolbachia are a group of intracellular bacteria that cause reproductive alterations in arthropods. Here, we describe the effects of two environmental factors (crowding and temperature) on phenotypic expression of feminization, the host's fecundity and Wolbachia infection intensity among life cycle stages in the naturally Wolbachia-infected copepod, Mesocyclops thermocyclopoides. The copepod was first found to be co-infected with Wolbachia A- and B-supergroups Wolbachia strains based on wsp primers. The relative Wolbachia infection intensity within individuals was determined using quantitative real-time PCR and was significantly higher in the B-supergroup than in the A-supergroup. Experimental results of temperature effect on bacterial density in each developmental stage revealed a significant decrease in Wolbachia infection intensity following exposure to high temperature (37°C) in both sexes and implied that Wolbachia might survive in room temperature (25°C) better than in high temperature. Experimental results of crowding effects on Wolbachia infection intensity suggested a negative correlation between copepod nauplii and Wolbachia infection intensity. No effect of rearing temperature on the sex ratio was reported although the fecundity was significantly decreased by high temperature. The results showed that Wolbachia infection intensity to be correlated with crowding conditions and was decreased following exposure of elevated temperature. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Effects of reproductive status, social rank, sex and group size on vigilance patterns in Przewalski's gazelle.

    Directory of Open Access Journals (Sweden)

    Chunlin Li

    Full Text Available Quantifying vigilance and exploring the underlying mechanisms has been the subject of numerous studies. Less attention has focused on the complex interplay between contributing factors such as reproductive status, social rank, sex and group size. Reproductive status and social rank are of particular interest due to their association with mating behavior. Mating activities in rutting season may interfere with typical patterns of vigilance and possibly interact with social rank. In addition, balancing the tradeoff between vigilance and life maintenance may represent a challenge for gregarious ungulate species rutting under harsh winter conditions. We studied vigilance patterns in the endangered Przewalski's gazelle (Procapra przewalskii during both the rutting and non-rutting seasons to examine these issues.Field observations were carried out with focal sampling during rutting and non-rutting season in 2008-2009. Results indicated a complex interplay between reproductive status, social rank, sex and group size in determining vigilance in this species. Vigilance decreased with group size in female but not in male gazelles. Males scanned more frequently and thus spent more time vigilant than females. Compared to non-rutting season, gazelles increased time spent scanning at the expense of bedding in rutting season. During the rutting season, territorial males spent a large proportion of time on rutting activities and were less vigilant than non-territorial males. Although territorial males may share collective risk detection with harem females, we suggest that they are probably more vulnerable to predation because they seemed reluctant to leave rut stands under threats.Vigilance behavior in Przewalski's gazelle was significantly affected by reproductive status, social rank, sex, group size and their complex interactions. These findings shed light on the mechanisms underlying vigilance patterns and the tradeoff between vigilance and other crucial

  7. Sex-role patterns, paternal rearing attitudes and child development in different social classes.

    Science.gov (United States)

    Nettelbladt, P; Uddenberg, N; Englesson, I

    1981-07-01

    Sex-role patterns, the father's rearing attitude and the child's intellectual and emotional development in different social classes were studied in a randomly selected sample of 58 Swedish unbroken families of a small child. Working class men and women married younger and the women were more often house-wives. Working class men had more often been reared in an "authoritarian" way and more often reared their children in the same way. Upper middle class men had taken a more active part in the care of the child. Working class children scored lower on the intelligence tests, especially the verbal ones and were more often estimated as socially immature.

  8. Experimentally manipulated brood sex ratios : Growth and survival in the black-headed gull (Larus ridibundus), a sexually dimorphic species

    NARCIS (Netherlands)

    Mueller, Wendt; Kalmbach, E; Eising, C.M; Groothuis, TGG; Dijkstra, C

    2005-01-01

    In sexually size dimorphic species, individuals of the larger sex often suffer from enhanced mortality during the nestling period. This has been attributed to higher nutritional requirements of the larger sex, which may render this sex more vulnerable to adverse food conditions. However, sex-biased

  9. Determination of Groundwater Flows Pattern in Surakarta Region Using the Activity Ratio of Tritium

    International Nuclear Information System (INIS)

    Wisjachudin Faisal; Agus Sulistyono; Brotopuspito, Kirbani Sri; Budi Legowo

    2002-01-01

    Tritium activity analysis on groundwater samples has been carried out at 13 different locations in Surakarta regency in order to determine the groundwater flow pattern. Tritium activity in the groundwater is measured by LSC (Liquid Scintillation Counter) Tri-Carb 2700TR Measurement of the optimum activity is done on sample volume ratio with cocktail 7.4 : 12.6 in operation 0.5 - 4.5 keV. The highest result fulfilled in the location of Lor In Hotel for 1566 dpm and the lowest is in the location of Kadipiro for 0.03 dpm. Those data have shown that groundwater flow come from western area to eastern area of Surakarta city. (author)

  10. 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.

  11. Reproductive and behavioral aspects of red-winged tinamous (Rhynchotus rufescens in groups with different sex ratios

    Directory of Open Access Journals (Sweden)

    VU Cromberg

    2007-09-01

    Full Text Available The aim of this research study was to evaluate the reproductive performance of tinamous submitted to five different male:female ratios. The study was carried out with 72 birds in a randomized experimental design with 4 replications. Tinamous were housed in cages, using the ratios of one (1:1, two (2:1, three (3:1 and four (4:1 females per male, and also one male was housed with three females individually (3R:1, in a rotational system. Reproductive records of the breeding season from September 2004 to March 2005 were used. The reproductive traits studied were: number of eggs laid, fertility, and percentage of eggs damaged and cracked by pecking. Nonparametric analyses of these traits were performed using Kruskal-Wallis test. Two replications of treatments 1:1 and 4:1, and one of treatment 2:1 were video-taped for three days, 12 hours/day. The videotapes were sampled according to the scan method to fit an ethogram. Birds were also watched for one hour per day to study dominance and agonistic behavior. None of the reproductive traits was affected by mating sex ratio (p<0.05. Female dominance could be related to displacement behavior (r=1.00, and male sitting in immobility plus sitting in activity behaviors were related to lower number of damaged eggs (r=-0.90. Social dominance was indirectly determined by displacement behavior in the study situation. A large number of damaged eggs occurred in all treatments, thereby not allowing a clear conclusion on the best male:female ratio.

  12. Impact of Glucose Tolerance Status, Sex, and Body Size on Glucose Absorption Patterns During OGTTs

    DEFF Research Database (Denmark)

    Faerch, K.; Pacini, G.; Nolan, J. J.

    2013-01-01

    OBJECTIVEWe studied whether patterns of glucose absorption during oral glucose tolerance tests (OGTTs) were abnormal in individuals with impaired glucose regulation and whether they were related to sex and body size (height and fat-free mass). We also examined how well differences in insulin......, reflected the differences for these parameters between those with normal and impaired glucose regulation as measured by gold-standard tests.CONCLUSIONSGlucose absorption patterns during an OGTT are significantly related to plasma glucose levels and body size, which should be taken into account when.......RESULTSMore rapid glucose absorption (P 0.036) and reduced late glucose absorption (P 0.039) were observed in the i-IFG group relative to NGT and i-IGT groups. Women with i-IGT had a lower early glucose absorption than did men with i-IGT (P = 0.041); however, this difference did not persist when differences in body...

  13. 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...

  14. 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.

  15. Sex-specific sleep patterns among university students in Lebanon: impact on depression and academic performance

    Directory of Open Access Journals (Sweden)

    Kabrita CS

    2016-06-01

    Full Text Available Colette S Kabrita,1 Theresa A Hajjar-Muça,2 1Department of Sciences, 2Department of Mathematics and Statistics, Faculty of Natural and Applied Sciences, Notre Dame University – Louaize, Zouk Mosbeh, Lebanon Abstract: Good sleep quality and quantity are fundamental to the maintenance of normal physiological processes. Changes in sleep patterns are commonly observed among young adults and are shown to impact neurocognitive, academic, and psychological well-being. Given the scarcity of sleep information about Lebanon and acknowledging the sex differences in various sleep dimensions, we conducted a study that aimed at assessing sex differences in sleep habits among university students in Lebanon in relation to psychoacademic status. A total of 540 students (50.6% females completed a questionnaire that inquired about sociodemographics and evaluated sleep quality and depression using the Pittsburg Sleep Quality Index (PSQI and Center for Epidemiological Studies Depression Scale (CES-D, respectively. The mean PSQI global score (6.57±3.49 indicated poor sleep, with no significant differences between men and women. The sleep/wake rhythm was delayed on weekends for both sexes. Females exhibited earlier bedtimes and rise times and longer sleep durations on both weekdays and weekends. However, unlike males females showed a greater phase delay in wake times than bedtimes on weekends (149 minutes vs 74 minutes, respectively. In all, 70.9% of females suffered from depressive symptoms, which was a significantly higher proportion compared with 58.5% of males (P<0.01. Based on the mean cumulative self-reported grade point average (GPA, the academic performance of females was significantly better than that of males (2.8±0.61 vs 2.65±0.61, P<0.05, respectively. Depression, as scored by CES-D, in females was significantly negatively correlated with the cumulative GPA (r=-0.278, P<0.01, earlier wake time (r=-0.168, P<0.05, and average sleep duration (r=-0

  16. Measurement, methods, and divergent patterns: Reassessing the effects of same-sex parents.

    Science.gov (United States)

    Cheng, Simon; Powell, Brian

    2015-07-01

    Scholars have noted that survey analysis of small subsamples-for example, same-sex parent families-is sensitive to researchers' analytical decisions, and even small differences in coding can profoundly shape empirical patterns. As an illustration, we reassess the findings of a recent article by Regnerus regarding the implications of being raised by gay and lesbian parents. Taking a close look at the New Family Structures Study (NFSS), we demonstrate the potential for misclassifying a non-negligible number of respondents as having been raised by parents who had a same-sex romantic relationship. We assess the implications of these possible misclassifications, along with other methodological considerations, by reanalyzing the NFSS in seven steps. The reanalysis offers evidence that the empirical patterns showcased in the original Regnerus article are fragile-so fragile that they appear largely a function of these possible misclassifications and other methodological choices. Our replication and reanalysis of Regnerus's study offer a cautionary illustration of the importance of double checking and critically assessing the implications of measurement and other methodological decisions in our and others' research. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Factors affecting incubation patterns and sex roles of black oystercatchers in Alaska

    Science.gov (United States)

    Spiegel, Caleb S.; Haig, Susan M.; Goldstein, Michael I.; Huso, Manuela M. P.

    2012-01-01

    Studies examining the effects of human disturbance on avian parental behavior and reproductive success are fundamental to bird conservation. However, many such studies fail to also consider the influence of natural threats, a variable environment, and parental roles. Our work examines interactive relationships of cyclical (time of day, tide, temperature, seasonality) and stochastic (natural/human disturbance) processes with incubation patterns (attendance, bout lengths, recess rates) of the Black Oystercatcher (Haematopus bachmani), a shorebird of conservation concern. We used 24-hour-per-day video monitoring of 13 molecularly-sexed breeding pairs to systematically examine incubation, revealing previously undocumented information that may inform conservation practices for the genus. Seven of 22 video-monitored nests failed, primarily from egg depredation by nocturnally-active mammals. Analyses of 3177 hrs of video footage indicated a near doubling of incubation bout lengths at night, corresponding to the increased risk of nighttime egg predation. Females had higher overall nest attendance (54% vs. 42%) and longer mean incubation bout lengths than males (88 min vs. 73 min). Uninterrupted incubation bouts were over twice as long as bouts interrupted by disturbance. Incubating males departed nests substantially more frequently due to nest-area disturbances than females in one, but not both, years of our study. Our findings suggest that sexes exhibit different, but complimentary, incubation patterns, facilitating efficient egg care in a dynamic environment with several nest threats. We emphasize the importance of considering natural influences when evaluating human threats to shorebird reproductive behavior and success.

  18. Does sex matter? Temporal and spatial patterns of cougar-human conflict in British Columbia.

    Science.gov (United States)

    Teichman, Kristine J; Cristescu, Bogdan; Nielsen, Scott E

    2013-01-01

    Wildlife-human conflicts occur wherever large carnivores overlap human inhabited areas. Conflict mitigation can be facilitated by understanding long-term dynamics and examining sex-structured conflict patterns. Predicting areas with high probability of conflict helps focus management strategies in order to proactively decrease carnivore mortality. We investigated the importance of cougar (Puma concolor) habitat, human landscape characteristics and the combination of habitat and human features on the temporal and spatial patterns of cougar-human conflicts in British Columbia. Conflicts (n = 1,727; 1978-2007) involved similar numbers of male and female cougars with conflict rate decreasing over the past decade. Conflicts were concentrated within the southern part of the province with the most conflicts per unit area occurring on Vancouver Island. For both sexes, the most supported spatial models for the most recent (1998-2007) conflicts contained both human and habitat variables. Conflicts were more likely to occur close to roads, at intermediate elevations and far from the northern edge of the cougar distribution range in British Columbia. Male cougar conflicts were more likely to occur in areas of intermediate human density. Unlike cougar conflicts in other regions, cattle density was not a significant predictor of conflict location. With human populations expanding, conflicts are expected to increase. Conservation tools, such as the maps predicting conflict hotspots from this study, can help focus management efforts to decrease carnivore-human conflict.

  19. Does sex matter? Temporal and spatial patterns of cougar-human conflict in British Columbia.

    Directory of Open Access Journals (Sweden)

    Kristine J Teichman

    Full Text Available Wildlife-human conflicts occur wherever large carnivores overlap human inhabited areas. Conflict mitigation can be facilitated by understanding long-term dynamics and examining sex-structured conflict patterns. Predicting areas with high probability of conflict helps focus management strategies in order to proactively decrease carnivore mortality. We investigated the importance of cougar (Puma concolor habitat, human landscape characteristics and the combination of habitat and human features on the temporal and spatial patterns of cougar-human conflicts in British Columbia. Conflicts (n = 1,727; 1978-2007 involved similar numbers of male and female cougars with conflict rate decreasing over the past decade. Conflicts were concentrated within the southern part of the province with the most conflicts per unit area occurring on Vancouver Island. For both sexes, the most supported spatial models for the most recent (1998-2007 conflicts contained both human and habitat variables. Conflicts were more likely to occur close to roads, at intermediate elevations and far from the northern edge of the cougar distribution range in British Columbia. Male cougar conflicts were more likely to occur in areas of intermediate human density. Unlike cougar conflicts in other regions, cattle density was not a significant predictor of conflict location. With human populations expanding, conflicts are expected to increase. Conservation tools, such as the maps predicting conflict hotspots from this study, can help focus management efforts to decrease carnivore-human conflict.

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

    Science.gov (United States)

    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.

  1. 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.

  2. Birth order, sibling sex ratio, handedness, and sexual orientation of male and female participants in a BBC internet research project.

    Science.gov (United States)

    Blanchard, Ray; Lippa, Richard A

    2007-04-01

    This study investigated the relations among sexual orientation, fraternal birth order (number of older brothers), and hand-preference. The participants were 87,798 men and 71,981 women who took part in a Web-based research project sponsored by the British Broadcasting Corporation (BBC). The results yielded some evidence confirming prior findings that non-right-handedness is associated with homosexuality in men and women, that older brothers increase the odds of homosexuality in men, and that the effect of older brothers on sexual orientation is limited to right-handed men. The evidence was weaker than in previous studies, however, probably because the usual relations among the variables of interest were partially obscured by the effects of other factors. Thus, the homosexual men and women had higher rates of non-right-handedness than their heterosexual counterparts, but the strongest handedness finding for both sexes was a marked tendency for participants who described themselves as ambidextrous also to describe themselves as bisexual. The birth order data were strongly affected by a tendency for the male participants to report an excess of older sisters, and the female participants to report an excess of older brothers. Statistical analyses confirmed that this was an artifact of the parental stopping rule, "Continue having children until you have offspring of both sexes." In subsequent analyses, participants were divided into those who did and did not have younger siblings, on the grounds that the data of the former would be less contaminated by the stopping rule. In the former subsample, the right-handed homo/bisexual males showed the typical high ratio of older brothers to older sisters, whereas the non-right-handed homo/bisexual males did not.

  3. 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...

  4. Influence of depth on sex-specific energy allocation patterns in a tropical reef fish

    Science.gov (United States)

    Hoey, J.; McCormick, M. I.; Hoey, A. S.

    2007-09-01

    The effect of depth on the distribution and sex-specific energy allocation patterns of a common coral reef fish, Chrysiptera rollandi (Pomacentridae), was investigated using depth-stratified collections over a broad depth range (5-39 m) and a translocation experiment. C. rollandi consistently selected rubble habitats at each depth, however abundance patterns did not reflect the availability of the preferred microhabitat suggesting a preference for depth as well as microhabitat. Reproductive investment (gonado-somatic index), energy stores (liver cell density and hepatocyte vacuolation), and overall body condition (hepato-somatic index and Fulton’s K) of female fish varied significantly among depths and among the three reefs sampled. Male conspecifics displayed no variation between depth or reef. Depth influenced growth dynamics, with faster initial growth rates and smaller mean asymptotic lengths with decreasing depth. In female fish, relative gonad weight and overall body condition (Fulton’s K and hepato-somatic index) were generally higher in shallower depths (≤10 m). Hepatic lipid storage was highest at the deepest sites sampled on each reef, whereas hepatic glycogen stores tended to decrease with depth. Depth was found to influence energy allocation dynamics in C. rollandi. While it is unclear what processes directly influenced the depth-related patterns in energy allocation, this study shows that individuals across a broad depth gradient are not all in the same physiological state and may contribute differentially to the population reproductive output.

  5. Size, sex and seasonal patterns in the assemblage of Carcharhiniformes in a sub-tropical bay.

    Science.gov (United States)

    Taylor, S M; Bennett, M B

    2013-01-01

    Size, sex and seasonal patterns among Carcharhiniformes were examined in shallow regions of Moreton Bay, Queensland, Australia. A total of 1259 sharks were caught, comprising 13 species. The Australian sharpnose shark Rhizoprionodon taylori and the blacktip complex Carcharhinus limbatus-Carcharhinus tilstoni comprised 55% of all shark individuals. Neonates were observed for five species including the dusky shark Carcharhinus obscurus, which contrary to previous reports was relatively abundant in shallow, predominantly estuarine waters. Three contrasting patterns of occurrence were observed: smaller species were abundant and present throughout much of their ontogeny, larger species were mainly caught as neonates or juveniles and vagrant species were only caught during the warmer months. The shark assemblage differed significantly among seasons. While many species were observed during the warmer months, species diversity was lower in winter when C. obscurus comprised 43% of the catch. Overall, the results indicated that spatial and temporal distribution patterns were not synchronous for all species. The capture of small numbers of neonate C. obscurus in late autumn and winter demonstrates that parturition among Carcharhiniformes is not confined to spring and summer in sub-tropical waters. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  6. Breeding of Djungarian hamsters (Phodopus sungorus): influence of parity and litter size on weaning success and offspring sex ratio.

    Science.gov (United States)

    Lerchl, A

    1995-04-01

    The reproduction of 368 breeding pairs of Djungarian hamsters (Phodopus sungorus) has been recorded and evaluated during 5 consecutive years. Three-hundred-and-eight pairs (= 83.7%) were successful breeders giving birth to 2113 litters (up to 13 per dam) with a total of 12,591 offspring (mean: 6.0 +/- 2.2 [+/- SD] per litter). One-hundred-and-fifty dams delivered within 25 days after pairing, indicating a breeding success in the first oestrous cycle of 40.8% of all pairs (95% confidence interval: 35.7%-46.0%). The average number of offspring was higher in the 2nd than in the first litter, reaching a maximum in the 3rd (6.8 +/- 2.0), and decreasing thereafter. The loss of offspring (mean: 24.2%) was higher in older parents and influenced by the number of offspring per litter, indicating that experience and stress contribute to breeding success. A small, but significantly higher number of females was recorded only when no loss of offspring occurred until weaning (females: 2.36 +/- 1.75; males: 2.16 +/- 1.63, P sex ratio towards favouring females with increased litter numbers, in contrast to the predictions of the Trivers-Willard hypothesis, at least with respect to the species and the breeding conditions as described in this report. Since all breeders were kept under long-day type photoperiods (16L:8D), no signs of seasonality in breeding outcome were noted.

  7. Sex-Specific Sociodemographic Correlates of Dietary Patterns in a Large Sample of French Elderly Individuals

    Directory of Open Access Journals (Sweden)

    Valentina A. Andreeva

    2016-08-01

    Full Text Available This cross-sectional analysis provides up-to-date information about dietary patterns (DP and their sociodemographic correlates in European elderly individuals. We studied 6686 enrollees aged 65+ (55% women in the ongoing French population-based NutriNet-Santé e-cohort. Diet was assessed via three 24 h records. The sex-specific correlates of factor analysis derived DP were identified with multivariable linear regression. Using 22 pre-defined food groups, three DP were extracted. The “healthy” DP (fruit, vegetables, grains, nuts, fish was positively associated with education, living alone, and being a former smoker (women, and negatively associated with being overweight, current smoker (men, age 75+ years, having hypertension, and obesity (women. The “western” DP (meat, appetizers, cheese, alcohol was positively associated with BMI (men and being a former/current smoker; it was negatively associated with age 75+ years (women and living alone. The “traditional” DP (bread, potatoes, milk, vegetables, butter, stock was positively associated with age and negatively associated with being a former/current smoker, education (men, and residing in an urban/semi-urban area. The findings support the diversity of DP among the elderly, highlighting sex-specific differences. The “healthy” DP explained the largest amount of variance in intake. Future studies could replicate the models in longitudinal and international contexts.

  8. Does the silver moss Bryum argenteum exhibit sex-specific patterns in vegetative growth rate, asexual fitness or prezygotic reproductive investment?

    Science.gov (United States)

    Horsley, Kimberly; Stark, Lloyd R; McLetchie, D Nicholas

    2011-05-01

    Expected life history trade-offs associated with sex differences in reproductive investment are often undetected in seed plants, with the difficulty arising from logistical issues of conducting controlled experiments. By controlling genotype, age and resource status of individuals, a bryophyte was assessed for sex-specific and location-specific patterns of vegetative, asexual and sexual growth/reproduction across a regional scale. Twelve genotypes (six male, six female) of the dioecious bryophyte Bryum argenteum were subcultured to remove environmental effects, regenerated asexually to replicate each genotype 16 times, and grown over a period of 92 d. Plants were assessed for growth rates, asexual and sexual reproductive traits, and allocation to above- and below-ground regenerative biomass. The degree of sexual versus asexual reproductive investment appears to be under genetic control, with three distinct ecotypes found in this study. Protonemal growth rate was positively correlated with asexual reproduction and sexual reproduction, whereas asexual reproduction was negatively correlated (appeared to trade-off) with vegetative growth (shoot production). No sex-specific trade-offs were detected. Female sex-expressing shoots were longer than males, but the sexes did not differ in growth traits, asexual traits, sexual induction times, or above- and below-ground biomass. Males, however, had much higher rates of inflorescence production than females, which translated into a significantly higher (24x) prezygotic investment for males relative to females. Evidence for three distinct ecotypes is presented for a bryophyte based on regeneration traits. Prior to zygote production, the sexes of this bryophyte did not differ in vegetative growth traits but significantly differed in reproductive investment, with the latter differences potentially implicated in the strongly biased female sex ratio. The disparity between males and females for prezygotic reproductive investment is

  9. Sex hormones affect acute and chronic stress responses in sexually dimorphic patterns : Consequences for depression models

    NARCIS (Netherlands)

    Guo, Lei; Chen, Yi-Xi; Hu, Yu-Ting; Wu, Xue-Yan; He, Yang; Wu, Juan-Li; Huang, Man-Li; Mason, M.R.J.; Bao, Ai-Min

    2018-01-01

    BACKGROUND: Alterations in peripheral sex hormones may play an important role in sex differences in terms of stress responses and mood disorders. It is not yet known whether and how stress-related brain systems and brain sex steroid levels fluctuate in relation to changes in peripheral sex hormone

  10. Patterns of international normalized ratio values among new warfarin patients with nonvalvular atrial fibrillation.

    Science.gov (United States)

    Nelson, Winnie W; Milentijevic, Dejan; Wang, Li; Baser, Onur; Damaraju, C V; Schein, Jeffrey R

    2016-12-01

    Limited information exists regarding the relationship between international normalized ratio (INR) control/stability and the discontinuation of warfarin therapy among patients with nonvalvular atrial fibrillation (NVAF). This study evaluated the association between INR stabilization and warfarin discontinuation and assessed INR patterns before and after INR stabilization among patients (≥18 years) with NVAF who newly initiated warfarin (Veterans Health Administration datasets; October 1, 2007 through September 30, 2012). Achievement of INR stabilization (≥3 consecutive in-range therapeutic INR measurements ≥7 days apart) was examined from warfarin initiation through the end of warfarin exposure. Proportion of time in therapeutic range during warfarin exposure was calculated (Rosendaal method) and categorized as at least 60% or less than 60%. Among 34 346 patients, 49.4% achieved INR stabilization (mean time to stabilization, 98 days). Approximately 40% of INR values were out-of-range, even after achieving stabilization. During 30 days following an INR 4.0 or higher, patients had more INR testing than the overall mean (2.51 vs. 1.67 tests). Warfarin discontinuation was 4.2 times more likely among patients without INR stabilization versus those with INR stabilization (P < 0.00001). Patients with poor INR control (time in therapeutic range <60%) were 1.76 times more likely to discontinue warfarin within 1 year (P < 0.0001). INR stabilization is a better predictor of warfarin discontinuation than poor INR control. Improved approaches are necessary to maintain appropriate anticoagulation levels among patients with NVAF.

  11. 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.

  12. Transactional relationships and sex with a woman in prostitution: prevalence and patterns in a representative sample of South African men.

    Science.gov (United States)

    Jewkes, Rachel; Morrell, Robert; Sikweyiya, Yandisa; Dunkle, Kristin; Penn-Kekana, Loveday

    2012-05-02

    Sex motivated by economic exchange is a public health concern as a driver of the Sub-Saharan African HIV epidemic. We describe patterns of engagement in transactional sexual relationships and sex with women in prostitution of South African men, and suggest interpretations that advance our understanding of the phenomenon. Cross-sectional study with a randomly-selected sample of 1645 sexually active men aged 18-49 years who completed interviews in a household study and were asked whether they had had sex with a woman in prostitution, or had had a relationship or sex they took to be motivated by the expectation of material gain (transactional sex). 18% of men had ever had sex with a woman in prostitution, 66% at least one type of transactional sexual relationship, only 30% of men had done neither. Most men had had a transactional relationship/sex with a main partner (58% of all men), 42% with a concurrent partner (or makhwapheni) and 44% with a once off partner, and there was almost no difference in reports of what was provided to women of different partner types. The majority of men distinguished the two types of sexual relationships and even among men who had once-off transactional sex and gave cash (n = 314), few (34%) reported that they had had sex with a 'prostitute'. Transactional sex was more common among men aged 25-34 years, less educated men and low income earners rather than those with none or higher income. Having had sex with a woman in prostitution varied little between social and demographic categories, but was less common among the unwaged or very low earners. The notion of 'transactional sex' developed through research with women does not translate easily to men. Many perceive expectations that they fulfil a provider role, with quid pro quo entitlement to sex. Men distinguished these circumstances of sex from having sex with a woman in prostitution. Whilst there may be similarities, when viewed relationally, these are quite distinct practices

  13. 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.

  14. 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

  15. 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...

  16. Are natural scientists more masculine than humanists? The association patterns between 2D:4D ratio and field of study.

    Science.gov (United States)

    Kainz, Sarah; Weitzer, Jacob; Zingale, Stefania; Köllner, Johanna; Albrecht, Cornelia; Gaidora, Angelika; Rudorfer, Marie-Theres; Nürnberger, Anna; Kirchengast, Sylvia

    2018-06-11

    Natural sciences are still considered as typical male fields, while humanities are interpreted as typical female topics. Economic, social but also biological factors are discussed to influence the choice of study field. In the present study, the impact of prenatal sex hormone exposure - estimated by 2D:4D ratio - on the choice of study field was analyzed. Two hundred Viennese students between the ages 18 and 28 years were enrolled. Lengths of the index finger and the ring finger were measured directly from the hand of the participants. 2D:4D ratios were calculated. Male and female students differed significantly in 2D:4D ratio. As expected, female students showed significantly higher 2D:4D ratios than their male counterparts ( p < 0.001). Male scientists and male humanists differed significantly in 2D:4D ratio. The 2D:4D of male humanists was significantly higher than that of scientists ( p = 0.037). Female scientists and female humanists however, did not differ significantly in 2D:4D ratio. Both showed a typical female 2D:4D ratio. This was also true of male humanists. Consequently low prenatal androgen exposure may be associated with the choice of humanities among male students.

  17. Transactional relationships and sex with a woman in prostitution: prevalence and patterns in a representative sample of South African men

    Science.gov (United States)

    2012-01-01

    Background Sex motivated by economic exchange is a public health concern as a driver of the Sub-Saharan African HIV epidemic. We describe patterns of engagement in transactional sexual relationships and sex with women in prostitution of South African men, and suggest interpretations that advance our understanding of the phenomenon. Methods Cross-sectional study with a randomly-selected sample of 1645 sexually active men aged 18–49 years who completed interviews in a household study and were asked whether they had had sex with a woman in prostitution, or had had a relationship or sex they took to be motivated by the expectation of material gain (transactional sex). Results 18% of men had ever had sex with a woman in prostitution, 66% at least one type of transactional sexual relationship, only 30% of men had done neither. Most men had had a transactional relationship/sex with a main partner (58% of all men), 42% with a concurrent partner (or makhwapheni) and 44% with a once off partner, and there was almost no difference in reports of what was provided to women of different partner types. The majority of men distinguished the two types of sexual relationships and even among men who had once-off transactional sex and gave cash (n = 314), few (34%) reported that they had had sex with a ‘prostitute’. Transactional sex was more common among men aged 25–34 years, less educated men and low income earners rather than those with none or higher income. Having had sex with a woman in prostitution varied little between social and demographic categories, but was less common among the unwaged or very low earners. Conclusions The notion of ‘transactional sex’ developed through research with women does not translate easily to men. Many perceive expectations that they fulfil a provider role, with quid pro quo entitlement to sex. Men distinguished these circumstances of sex from having sex with a woman in prostitution. Whilst there may be similarities, when

  18. Sex-specific differences in hemodialysis prevalence and practices and the male-to-female mortality rate: the Dialysis Outcomes and Practice Patterns Study (DOPPS.

    Directory of Open Access Journals (Sweden)

    Manfred Hecking

    2014-10-01

    Full Text Available BACKGROUND: A comprehensive analysis of sex-specific differences in the characteristics, treatment, and outcomes of individuals with end-stage renal disease undergoing dialysis might reveal treatment inequalities and targets to improve sex-specific patient care. Here we describe hemodialysis prevalence and patient characteristics by sex, compare the adult male-to-female mortality rate with data from the general population, and evaluate sex interactions with mortality. METHODS AND FINDINGS: We assessed the Human Mortality Database and 206,374 patients receiving hemodialysis from 12 countries (Australia, Belgium, Canada, France, Germany, Italy, Japan, New Zealand, Spain, Sweden, the UK, and the US participating in the international, prospective Dialysis Outcomes and Practice Patterns Study (DOPPS between June 1996 and March 2012. Among 35,964 sampled DOPPS patients with full data collection, we studied patient characteristics (descriptively and mortality (via Cox regression by sex. In all age groups, more men than women were on hemodialysis (59% versus 41% overall, with large differences observed between countries. The average estimated glomerular filtration rate at hemodialysis initiation was higher in men than women. The male-to-female mortality rate ratio in the general population varied from 1.5 to 2.6 for age groups <75 y, but in hemodialysis patients was close to one. Compared to women, men were younger (mean = 61.9 ± standard deviation 14.6 versus 63.1 ± 14.5 y, were less frequently obese, were more frequently married and recipients of a kidney transplant, more frequently had coronary artery disease, and were less frequently depressed. Interaction analyses showed that the mortality risk associated with several comorbidities and hemodialysis catheter use was lower for men (hazard ratio [HR] = 1.11 than women (HR = 1.33, interaction p<0.001. This study is limited by its inability to establish causality for the observed sex

  19. Patterns and Environmental Determinants of Medicinal Plant : Vascular Plant Ratios in Xinjiang, Northwest China

    Science.gov (United States)

    Zhang, Bengang; Xiao, Peigen; Qi, Yaodong; Zhang, Zhao; Liu, Haitao; Li, Xiaojin; Wang, Guoping; Terwei, André

    2016-01-01

    With both a full collection of native vascular plant distributions and a full checklist of source plants of the Chinese Materia Medica (CMM), the Uygur Medicine (UM), and the Kazak Medicine (KM) for the Xinjiang region, we defined medicinal plant: vascular plant ratios (simplified as medicinal plant ratios hereafter) as the value of medicinal plant richness divided by vascular plant richness. We aimed to find whether the ratios are constant or change in different environments, which environmental variables determine medicinal plant ratios, and whether the ratios are more influenced by human or by natural environments. Finally, suggestions for medicinal plant conservation were addressed. We found that (1) medicinal plant ratios were not constant, and they were high in the Tarim Basin which was largely covered by desert, while they were relatively low in mountainous areas, especially in the Tianshan Mountains where the general species richness was high; (2) medicinal plant ratios were not significantly influenced by human activities, indicated by human population density distributions, but they were highly correlated with plant species richness and climate, i.e. ratios decreased with plant species richness and MAP, and were related quadratically with MAT; (3) CMM ratio and UM ratio were more influenced by plant richness than by climate, while KM ratio was more influenced by climate. We concluded that the percentages of plants used as medicines were not influenced by distances from human settlements, but were determined by species richness or climate. We suggest that (1), in general, the medicinal plant ratio could be a complementary indicator for medicinal plant conservation planning and (2), for the region of Xinjiang, not only high diversity areas, but also some extreme environments should be considered as compensation for a better protection of medicinal plants. PMID:27391239

  20. Patterns and Environmental Determinants of Medicinal Plant : Vascular Plant Ratios in Xinjiang, Northwest China.

    Directory of Open Access Journals (Sweden)

    Liping Li

    Full Text Available With both a full collection of native vascular plant distributions and a full checklist of source plants of the Chinese Materia Medica (CMM, the Uygur Medicine (UM, and the Kazak Medicine (KM for the Xinjiang region, we defined medicinal plant: vascular plant ratios (simplified as medicinal plant ratios hereafter as the value of medicinal plant richness divided by vascular plant richness. We aimed to find whether the ratios are constant or change in different environments, which environmental variables determine medicinal plant ratios, and whether the ratios are more influenced by human or by natural environments. Finally, suggestions for medicinal plant conservation were addressed. We found that (1 medicinal plant ratios were not constant, and they were high in the Tarim Basin which was largely covered by desert, while they were relatively low in mountainous areas, especially in the Tianshan Mountains where the general species richness was high; (2 medicinal plant ratios were not significantly influenced by human activities, indicated by human population density distributions, but they were highly correlated with plant species richness and climate, i.e. ratios decreased with plant species richness and MAP, and were related quadratically with MAT; (3 CMM ratio and UM ratio were more influenced by plant richness than by climate, while KM ratio was more influenced by climate. We concluded that the percentages of plants used as medicines were not influenced by distances from human settlements, but were determined by species richness or climate. We suggest that (1, in general, the medicinal plant ratio could be a complementary indicator for medicinal plant conservation planning and (2, for the region of Xinjiang, not only high diversity areas, but also some extreme environments should be considered as compensation for a better protection of medicinal plants.

  1. Patterns and Environmental Determinants of Medicinal Plant : Vascular Plant Ratios in Xinjiang, Northwest China.

    Science.gov (United States)

    Li, Liping; Zhang, Bengang; Xiao, Peigen; Qi, Yaodong; Zhang, Zhao; Liu, Haitao; Li, Xiaojin; Wang, Guoping; Terwei, André

    2016-01-01

    With both a full collection of native vascular plant distributions and a full checklist of source plants of the Chinese Materia Medica (CMM), the Uygur Medicine (UM), and the Kazak Medicine (KM) for the Xinjiang region, we defined medicinal plant: vascular plant ratios (simplified as medicinal plant ratios hereafter) as the value of medicinal plant richness divided by vascular plant richness. We aimed to find whether the ratios are constant or change in different environments, which environmental variables determine medicinal plant ratios, and whether the ratios are more influenced by human or by natural environments. Finally, suggestions for medicinal plant conservation were addressed. We found that (1) medicinal plant ratios were not constant, and they were high in the Tarim Basin which was largely covered by desert, while they were relatively low in mountainous areas, especially in the Tianshan Mountains where the general species richness was high; (2) medicinal plant ratios were not significantly influenced by human activities, indicated by human population density distributions, but they were highly correlated with plant species richness and climate, i.e. ratios decreased with plant species richness and MAP, and were related quadratically with MAT; (3) CMM ratio and UM ratio were more influenced by plant richness than by climate, while KM ratio was more influenced by climate. We concluded that the percentages of plants used as medicines were not influenced by distances from human settlements, but were determined by species richness or climate. We suggest that (1), in general, the medicinal plant ratio could be a complementary indicator for medicinal plant conservation planning and (2), for the region of Xinjiang, not only high diversity areas, but also some extreme environments should be considered as compensation for a better protection of medicinal plants.

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

    NARCIS (Netherlands)

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

    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. In sexual size dimorphic

  3. Determine sex ratios of green turtles along the U.S. West Coast through examinations of hormones

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A testosterone (T) enzyme-linked immunosorbent assay (ELISA) was validated for use with green turtle plasma in order to determine the sex of juvenile turtles. We...

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Sex differences in the aging pattern of renin-angiotensin system serum peptidases.

    Science.gov (United States)

    Fernández-Atucha, A; Izagirre, A; Fraile-Bermúdez, A B; Kortajarena, M; Larrinaga, G; Martinez-Lage, P; Echevarría, E; Gil, J

    2017-01-01

    Serum peptidases, such as angiotensin-converting enzyme (ACE), angiotensin-converting enzyme-2 (ACE2), neutral endopeptidase (NEP), aminopeptidase N (APN), and aminopeptidase A (APA), are important elements of the renin-angiotensin system (RAS). Dysregulation of these enzymes has been associated with hypertension and cardiovascular risk. In the present study, serum activities of RAS peptidases were analyzed to evaluate the existence of sexual differences, with a possible different pattern in pre- and post-andropausal/post-menopausal participants. One hundred and eighteen healthy men and women between 41 and 70 years of age (58 women and 60 men) were recruited to participate in the study. Serum RAS-regulating enzymes were measured by spectrofluorimetry. Enzymatic activity was recorded as units of enzyme per milliliter of serum (U/mL). Significantly lower serum APA activity was observed in men with respect to women; no sex differences were detected for ACE, ACE2, NEP, or APN. Significantly lower APA and ACE serum activity were observed in older men compared to older women. In contrast, younger (menopausia, on the critical serum enzymatic activities of the RAS, which could correlate with sexual differences in cardiovascular risk.

  6. 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.

  7. Effect of extra-pair paternity and parental quality on brood sex ratio in the scarlet rosefinch Carpodacus erythrinus

    Czech Academy of Sciences Publication Activity Database

    Poláková, Radka; Schnitzer, J.; Vinkler, Michal; Bryja, Josef; Munclinger, P.; Albrecht, Tomáš

    2012-01-01

    Roč. 61, 3-4 (2012), s. 225-232 ISSN 0139-7893 R&D Projects: GA MŠk LC06073; GA ČR GA206/06/0851 Institutional support: RVO:68081766 Keywords : sex allocation * extra-pair mating * parental attractiveness Subject RIV: EG - Zoology Impact factor: 0.494, year: 2012

  8. Seasonal dynamics in community structure, abundance, body size and sex ratio in two species of Neotropical annual fishes

    Czech Academy of Sciences Publication Activity Database

    Lanés, L. E. K.; Godoy, R. S.; Maltchik, L.; Polačik, Matej; Blažek, Radim; Vrtílek, Milan; Reichard, Martin

    2016-01-01

    Roč. 89, č. 5 (2016), s. 2345-2364 ISSN 0022-1112 Institutional support: RVO:68081766 Keywords : coastal floodplain * coexistence * Lagoa do Peixe * life cycle * sex-biased mortality * temporary habitat Subject RIV: EG - Zoology Impact factor: 1.519, year: 2016

  9. Attend or defend? Sex differences in behavioral, autonomic, and respiratory response patterns to emotion-eliciting films.

    Science.gov (United States)

    Wilhelm, Frank H; Rattel, Julina A; Wegerer, Melanie; Liedlgruber, Michael; Schweighofer, Simon; Kreibig, Sylvia D; Kolodyazhniy, Vitaliy; Blechert, Jens

    2017-12-01

    Sex differences in emotional reactivity have been studied primarily for negative but less so for positive stimuli; likewise, sex differences in the psychophysiological response-patterning during such stimuli are poorly understood. Thus, the present study examined sex differences in response to negative/positive and high/low arousing films (classified as threat-, loss-, achievement-, and recreation-related, vs. neutral films), while measuring 18 muscular, autonomic, and respiratory parameters. Sex differences emerged for all films, but were most prominent for threat-related films: Despite equivalent valence and arousal ratings, women displayed more facial-muscular and respiratory responding than men and pronounced sympathetic activation (preejection period, other cardiovascular and electrodermal measures), while men showed coactivated sympathetic/parasympathetic responding (including increased respiratory sinus arrhythmia). This indicates a prototypical threat-related defense response in women, while men showed a pattern of sustained orienting, which can be understood as a shift toward less threat proximity in the defense cascade model. Clinical implications are discussed within a socio-evolutionary framework. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. African American women and sexually transmitted infections: The contextual influence of unbalanced sex ratios and individual risk behaviors.

    Science.gov (United States)

    Oser, Carrie B; Pullen, Erin; Stevens-Watkins, Danelle; Perry, Brea L; Havens, Jennifer R; Staton-Tindall, Michele; Leukefeld, Carl G

    2017-10-01

    This study uses data from 564 African American women to examine the correlates of lifetime prevalence of a sexually transmitted infection (STI). Specifically, we test the effects of perceptions about the availability of African American males, five partner characteristics, and drug history. At the bivariate-level, women with an STI diagnosis were significantly more likely to have dated a man who was married, older, had sex with another man, involved in concurrent partnerships, and had been incarcerated. About half of the participants stated it was difficult to find an eligible African American male and attributed the limited pool of same-race partners to drug trafficking, a lack of monogamy, and high rates of incarceration. Multivariate analyses revealed having dated a man who had concurrent sexual partnerships or had been incarcerated, as well as drug use during sex were positively associated with ever having an STI. Individual and contextual implications are addressed.

  11. Laboratory studies on insecticide resistance, alcohol tolerance and sex ratio distortion by meiotic drive in the Mediterranean fruit fly, Ceratitis capitata (Wied.)

    International Nuclear Information System (INIS)

    Wood, R.J.

    1990-01-01

    Three approaches to developing a genetic sexing technique for the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann), are discussed. Laboratory studies in late third instar larvae of the medfly revealed a potential for dieldrin resistance. A programme of sib selection produced the DiR strain, more than 60x resistante to dieldrin with cross-resistance to other cyclodienes, HCH, malathion and permethrin. Adults were not resistant. Crosses showed dieldrin resistance to be monofactorial, subject to a modifying effect from the genetic background on the expression of the homozygote. The 'backcrossing with selection' technique was used to separate dieldrin and malathion resistance but, in the process, resistance to both insecticides was lost after four to eight generations. Attempts to induce male linkage of the R gene by X irradiation were unsuccessful. Further genetic studies on resistance are recommended. With a view to producing an ethanol sensitive strain homozygous for an ADH null mutation (Adh - /Adh - ), pentenol selection of late third instar larvae was carried out, combined with ethyl methane sulphonate (EMS) treatments of adults. This produced a maximum of 15x tolerance of pentenol but no associated change in ethanol tolerance. Electrophoresis (PAGE) showed that two major ADH systems were at their most active in late third instar larvae. A gene causing a male distorted sex ratio in the progeny of males carrying it was isolated after X irradiation. The expression of the gene, which appears to be an example of meiotic drive, was enhanced by reducing the ambient temperature of parent flies from 26 deg. C+-2.0 to 18 deg. C+-1.5 during days 2-5 of pupal development. Selection to increase the expression of the gene produced families with less than 20% females but sex ratio tended to revert towards normal in subsequent generations. A potential is seen for producing strains in which sex ratio can be regulated by temperature. (author). 30 refs, 5 figs, 2

  12. Sex-ratio, seasonality and long-term variation in maturation and spawning of the brown shrimp Crangon crangon (L.) in the German Bight (North Sea)

    Science.gov (United States)

    Siegel, V.; Damm, U.; Neudecker, T.

    2008-12-01

    Aspects of the reproductive and maturation biology of the brown shrimp Crangon crangon (L.) were studied in various subareas of the German Bight (North Sea). The size-specific sex ratio of C. crangon was examined based on length frequency distribution data. The sex ratio for the smallest size groups at which sex was determined was typically around 0.5, indicating an even ratio between males and females. The proportion of females decreased in the 30-45 mm size range. In length classes larger than 50 mm, the proportion of females constantly increases to 100% at around 60 mm total length. We concluded that sex reversal from male to female may not occur in C. crangon. Size at sexual maturity was determined from the proportion of ovigerous females. Size at maturity ( L 50) was estimated as 55.4 and 62.0 mm total length for spring and winter data, respectively. The seasonal spawning cycle was studied over the period 1958-2005. Between mid February and late June and for size classes larger than 65 mm ovigerous shrimps exceeded 80% and reached up to 100% of the females in the population. This period can be seen as the core spawning season. From early August to early December the proportion of ovigerous shrimps in the female population is very low. Interannual differences in the seasonal process are obvious with a dramatic decline in C. crangon reproductive success in the late 1980s. Various options are discussed for the reasons of the decline and recovery of the reproductive performance.

  13. Patterns of molecular evolution of an avian neo-sex chromosome.

    Science.gov (United States)

    Pala, Irene; Hasselquist, Dennis; Bensch, Staffan; Hansson, Bengt

    2012-12-01

    Newer parts of sex chromosomes, neo-sex chromosomes, offer unique possibilities for studying gene degeneration and sequence evolution in response to loss of recombination and population size decrease. We have recently described a neo-sex chromosome system in Sylvioidea passerines that has resulted from a fusion between the first half (10 Mb) of chromosome 4a and the ancestral sex chromosomes. In this study, we report the results of molecular analyses of neo-Z and neo-W gametologs and intronic parts of neo-Z and autosomal genes on the second half of chromosome 4a in three species within different Sylvioidea lineages (Acrocephalidea, Timaliidae, and Alaudidae). In line with hypotheses of neo-sex chromosome evolution, we observe 1) lower genetic diversity of neo-Z genes compared with autosomal genes, 2) moderate synonymous and weak nonsynonymous sequence divergence between neo-Z and neo-W gametologs, and 3) lower GC content on neo-W than neo-Z gametologs. Phylogenetic reconstruction of eight neo-Z and neo-W gametologs suggests that recombination continued after the split of Alaudidae from the rest of the Sylvioidea lineages (i.e., after ~42.2 Ma) and with some exceptions also after the split of Acrocephalidea and Timaliidae (i.e., after ~39.4 Ma). The Sylvioidea neo-sex chromosome shares classical evolutionary features with the ancestral sex chromosomes but, as expected from its more recent origin, shows weaker divergence between gametologs.

  14. Cross-sex pattern of bone mineral density in early onset gender identity disorder.

    Science.gov (United States)

    Haraldsen, I R; Haug, E; Falch, J; Egeland, T; Opjordsmoen, S

    2007-09-01

    Hormonally controlled differences in bone mineral density (BMD) between males and females are well studied. The effects of cross-sex hormones on bone metabolism in patients with early onset gender identity disorder (EO-GID), however, are unclear. We examined BMD, total body fat (TBF) and total lean body mass (TLBM) in patients prior to initiation of sex hormone treatment and during treatment at months 3 and 12. The study included 33 EO-GID patients who were approved for sex reassignment and a control group of 122 healthy Norwegians (males, n=77; females, n=45). Male patients (n=12) received an oral dose of 50 mug ethinylestradiol daily for the first 3 months and 100 mug daily thereafter. Female patients (n=21) received 250 mg testosterone enantate intramuscularly every third week. BMD, TBF and TLBM were estimated using dual energy X-ray absorptiometry (DXA). In male patients, the DXA measurements except TBF were significantly lower compared to their same-sex control group at baseline and did not change during treatment. In female patients, the DXA measurements were slightly higher than in same-sex controls at baseline and also remained unchanged during treatment. In conclusion, this study reports that body composition and bone density of EO-GID patients show less pronounced sex differences compared to controls and that bone density was unaffected by cross-sex hormone treatment.

  15. The Eyes Have It: Sex and Sexual Orientation Differences in Pupil Dilation Patterns

    Science.gov (United States)

    Rieger, Gerulf; Savin-Williams, Ritch C.

    2012-01-01

    Recent research suggests profound sex and sexual orientation differences in sexual response. These results, however, are based on measures of genital arousal, which have potential limitations such as volunteer bias and differential measures for the sexes. The present study introduces a measure less affected by these limitations. We assessed the pupil dilation of 325 men and women of various sexual orientations to male and female erotic stimuli. Results supported hypotheses. In general, self-reported sexual orientation corresponded with pupil dilation to men and women. Among men, substantial dilation to both sexes was most common in bisexual-identified men. In contrast, among women, substantial dilation to both sexes was most common in heterosexual-identified women. Possible reasons for these differences are discussed. Because the measure of pupil dilation is less invasive than previous measures of sexual response, it allows for studying diverse age and cultural populations, usually not included in sexuality research. PMID:22870196

  16. The Dynamics of Male Brooding, Mating Patterns, ad Sex Roles in Pipefishes and Seahorses (Family Syngnathidae)

    OpenAIRE

    Wilson, Anthony Bruce; Ahnesjö, Ingrid; Vincent, Amanda C. J.; Meyer, Axel

    2003-01-01

    Modern theory predicts that relative parental investment of the sexes in their young is a key factor responsible for sexual selection. Seahorses and pipefishes (family Syngnathidae) are extraordinary among fishes in their remarkable adaptations for paternal care and frequent occurrences of sex-role reversals (i.e., female-female competition for mates), offering exceptional opportunities to test predictions of sexual selection theory. During mating, the female transfers eggs into or onto speci...

  17. 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.

  18. An investigation of application of the golden ratio and Fibonacci sequence in fashion design and pattern making

    Science.gov (United States)

    Kazlacheva, Z. I.

    2017-10-01

    The Golden ratio and Fibonacci sequence are used as proportions in design as symbols of beauty and harmony. That symbolism is a result of the strong connections in their mathematical nature. The Golden section is a number, introduced with Greek letter φ, which is found by dividing a line into two parts as the longer part divided by the smaller part is equal as the whole length of longer and smaller parts divided by the longer part. Fibonacci sequence is a series of numbers where every number is equal to the two numbers before it. An investigation of application of proportions based on the Golden ratio and Fibonacci sequence in the fashion design and pattern making of ladies’ clothing is the main aim of the paper. Based on the study it may be concluded that in fashion design and pattern making the Golden ratio and Fibonacci sequence can be used in creation of beautiful and harmonic forms directly or with the help of geometrical figures as: In directly use the Golden and Fibonacci numbers proportions can be in one and the same or different directions. In the application with the help of geometrical shapes the Golden and Fibonacci figures combine proportioning and form creation. The Golden and Fibonacci shapes can be used directly as forms or as frames of forms creation of elements and pieces. Its application can be in different directions and location according the bodice. The Golden section and Fibonacci sequence can combine proportions with other principles of design as symmetry, rhythm, etc.

  19. Sex ratio and body size in Cobitis elongatoides and Sabanejewia balcanica (Cypriniformes; Cobitidae) from a thermal spring

    Czech Academy of Sciences Publication Activity Database

    Bohlen, Jörg; Freyhof, J.; Nolte, A.

    2008-01-01

    Roč. 57, 1-2 (2008), s. 191-197 ISSN 0139-7893. [International Conference Loaches of the genus Cobitis and related genera. Šibenik, 24.09.2006-29.09.2006] R&D Projects: GA ČR GA206/05/2556; GA AV ČR IAA600450508 Institutional research plan: CEZ:AV0Z50450515 Keywords : environmental sex determination * Fisher's principle * cobitine loach Subject RIV: EG - Zoology Impact factor: 0.522, year: 2008

  20. Estrogenic exposure affects metamorphosis and alters sex ratios in the northern leopard frog (Rana pipiens): identifying critically vulnerable periods of development.

    Science.gov (United States)

    Hogan, Natacha S; Duarte, Paula; Wade, Michael G; Lean, David R S; Trudeau, Vance L

    2008-05-01

    During the transformation from larval tadpole to juvenile frog, there are critical periods of metamorphic development and sex differentiation that may be particularly sensitive to endocrine disruption. The aim of the present study was to identify sensitive developmental periods for estrogenic endocrine disruption in the northern leopard frog (Rana pipiens) using short, targeted exposures to the synthetic estrogen, ethinylestradiol (EE2). Post-hatch tadpoles (Gosner stage 27) were exposed over five distinct periods of metamorphosis: early (stage 27-30), mid (stage 30-36), early and mid (stage 27-36), late (stage 36-42), and the entire metamorphic period (chronic; stage 27-42). For each period, animals were sampled immediately following the EE2 exposure and at metamorphic climax (stage 42). The effects of EE2 on metamorphic development and sex differentiation were assessed through measures of length, weight, developmental stage, days to metamorphosis, sex ratios and incidence of gonadal intersex. Our results show that tadpoles exposed to EE2 during mid-metamorphosis were developmentally delayed immediately following exposure and took 2 weeks longer to reach metamorphic climax. In the unexposed groups, there was low proportion (0.15) of intersex tadpoles at stage 30 and gonads appeared to be morphologically distinct (male and female) in all individuals by stage 36. Tadpoles exposed early in development displayed a strong female-biased sex ratio compared to the controls. Moreover, these effects were also seen at metamorphic climax, approximately 2-3 months after the exposure period, demonstrating that transient early life-stage exposure to estrogen can induce effects on the reproductive organs that persist into the beginning of adult life-stages.

  1. Predicting healthy lifestyle patterns among retirement age older adults in the WELL study: a latent class analysis of sex differences.

    Science.gov (United States)

    Södergren, Marita; Wang, Wei Chun; Salmon, Jo; Ball, Kylie; Crawford, David; McNaughton, Sarah A

    2014-01-01

    The aim of this study was to identify subgroups of retirement age older adults with respect to their lifestyle patterns of eating, drinking, smoking, physical activity and TV viewing behaviors, and to examine the association between these patterns and socio-demographic covariates. The sample consisted of 3133 older adults aged 55-65 years from the Wellbeing, Eating and Exercise for a Long Life (WELL) study, 2010. This study used latent class analysis (stratified by sex), with a set of lifestyle indicators and including socio-demographic covariates. Statistical analyses were performed by generalized linear latent and mixed models in Stata. Two classes of lifestyle patterns were identified: Healthy (53% men and 72% women) and less healthy lifestyles. Physical activity, TV-viewing time, and fruit intake were good indicators distinguishing the "Healthier" class, whereas consumption of vegetables, alcohol (men) and fast food (women) could not clearly discriminate older adults in the two classes. Class membership was associated with education, body mass index, and self-rated health. This study contributes to the literature on lifestyle behaviors among older adults, and provides evidence that there are meaningful sex differences in lifestyle behaviors between subgroups of older adults. From a policy perspective, understanding indicators or "markers" of healthy and less healthy lifestyle patterns is important for identifying target groups for interventions. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  2. Antidepressant-like effects of guanfacine and sex-specific differences in effects on c-fos immunoreactivity and paired-pulse ratio in male and female mice.

    Science.gov (United States)

    Mineur, Yann S; Bentham, Matthew P; Zhou, Wen-Liang; Plantenga, Margreet E; McKee, Sherry A; Picciotto, Marina R

    2015-10-01

    The a2A-noradrenergic agonist guanfacine can decreases stress-induced smoking in female, but not male, human smokers. It is not known whether these effects are due to effects on mood regulation and/or result from nicotinic-cholinergic interactions. The objective of the study was to determine whether there are sex differences in the effect of guanfacine in tests of anxiolytic and antidepressant efficacy in mice at baseline and in a hypercholinergic model of depression induced by the acetylcholinesterase inhibitor physostigmine. The effects of guanfacine were measured in the light/dark box, tail suspension, and the forced swim test in female and male C57BL/6J mice. In parallel, electrophysiological properties were evaluated in the prefrontal cortex, a critical brain region involved in stress responses. c-fos immunoreactivity was measured in other brain regions known to regulate mood. Despite a baseline sex difference in behavior in the forced swim test (female mice were more immobile), guanfacine had similar, dose-dependent, antidepressant-like effects in mice of both sexes (optimal dose, 0.15 mg/kg). An antidepressant-like effect of guanfacine was also observed following pre-treatment with physostigmine. A sex difference in the paired-pulse ratio in the prefrontal cortex (PFC) (male, 1.4; female, 2.1) was observed at baseline that was normalized by guanfacine. Other brain areas involved in cholinergic control of depression-like behaviors, including the basolateral amygdala and lateral septum, showed sex-specific changes in c-fos expression. Guanfacine has a robust antidepressant-like effect and can reverse a depression-like state induced by increased acetylcholine (ACh) signaling. These data suggest that different brain areas are recruited in female and male mice, despite similar behavioral responses to guanfacine.

  3. Sex differences in vocal patterns in the northern muriqui (Brachyteles hypoxanthus).

    Science.gov (United States)

    Arnedo, Luisa F; Mendes, Francisco D C; Strier, Karen B

    2010-02-01

    We investigated whether sex differences in spatial dynamics correlate with rates of staccato and neigh vocalizations in northern muriquis (Brachyteles hypoxanthus) at the Reserva Particular do Patrimônio Natural-Feliciano Miguel Abdala, Minas Gerais, Brazil. A total of 2,727 10 min focal subject samples were collected on 32 adult females and 31 adult males between April 2007 and March 2008. Compared with males, females spent a significantly lower proportion of their time in proximity to other group members and gave staccatos at significantly higher rates while feeding, resting, and traveling. Conversely, males emitted neigh vocalizations at significantly higher rates than females when feeding and resting only. Both sexes gave significantly more staccatos when feeding than when they were engaged in other activities, but their respective rates of neighs did not vary across activities. Both females and males emitted staccato vocalizations at significantly higher rates during times of the year when preferred foods were scarce, but no seasonal differences in the rates of neigh vocalizations were observed in either sex. Females and males showed a reduction in the number of neighbors following staccato vocalizations and an increase in the number of neighbors following neigh vocalizations. Our findings of sex differences in the rates of staccato and neigh vocalizations and the effects of these vocalizations on interindividual spacing are consistent with sex differences in spatial dynamics, and confirm the role of vocal communication in mediating spatial associations in this species.

  4. Sex Differences in Neurophysiological Activation Patterns During Phonological Input Processing: An Influencing Factor for Normative Data.

    Science.gov (United States)

    Aerts, Annelies; van Mierlo, Pieter; Hartsuiker, Robert J; Santens, Patrick; De Letter, Miet

    2015-11-01

    In the context of neurophysiological normative data, it has been established that aging has a significant impact on neurophysiological correlates of auditory phonological input processes, such as phoneme discrimination (PD) and word recognition (WR). Besides age, sex is another demographic factor that influences several language processes. We aimed to disentangle whether sex has a similar effect on PD and WR. Event-related potentials (ERPs) were recorded in 20 men and 24 women. During PD, three phonemic contrasts (place and manner of articulation and voicing) were compared using the attentive P300 and pre-attentive Mismatch Negativity. To investigate WR, real words were contrasted with pseudowords in a pre-attentive oddball task. Women demonstrated a larger sensitivity to spectrotemporal differences, as evidenced by larger P300 responses to the place of articulation (PoA) contrast and larger P300 and MMN responses than men in PoA-based PD. Men did not display such sensitivity. Attention played an important role, considering that women needed more attentional resources to differentiate between PoA and the other phonemic contrasts. During WR, pseudowords evoked larger amplitudes already 100 ms post-stimulus independent of sex. However, women had decreased P200 latencies, but longer N400 latencies in response to pseudowords, whereas men showed increased N400 latencies compared to women in response to real words. The current results demonstrate significant sex-related influences on phonological input processes. Therefore, existing neurophysiological normative data for age should be complemented for the factor sex.

  5. The Slow:Fast substitution ratio reveals changing patterns of natural selection in gamma-proteobacterial genomes

    Energy Technology Data Exchange (ETDEWEB)

    Alm, Eric; Shapiro, B. Jesse

    2009-04-15

    Different microbial species are thought to occupy distinct ecological niches, subjecting each species to unique selective constraints, which may leave a recognizable signal in their genomes. Thus, it may be possible to extract insight into the genetic basis of ecological differences among lineages by identifying unusual patterns of substitutions in orthologous gene or protein sequences. We use the ratio of substitutions in slow versus fast-evolving sites (nucleotides in DNA, or amino acids in protein sequence) to quantify deviations from the typical pattern of selective constraint observed across bacterial lineages. We propose that elevated S:F in one branch (an excess of slow-site substitutions) can indicate a functionally-relevant change, due to either positive selection or relaxed evolutionary constraint. In a genome-wide comparative study of gamma-proteobacterial proteins, we find that cell-surface proteins involved with motility and secretion functions often have high S:F ratios, while information-processing genes do not. Change in evolutionary constraints in some species is evidenced by increased S:F ratios within functionally-related sets of genes (e.g., energy production in Pseudomonas fluorescens), while other species apparently evolve mostly by drift (e.g., uniformly elevated S:F across most genes in Buchnera spp.). Overall, S:F reveals several species-specific, protein-level changes with potential functional/ecological importance. As microbial genome projects yield more species-rich gene-trees, the S:F ratio will become an increasingly powerful tool for uncovering functional genetic differences among species.

  6. A cohort study of the association between secondary sex ratio and parental exposure to polybrominated biphenyl (PBB and polychlorinated biphenyl (PCB

    Directory of Open Access Journals (Sweden)

    Terrell Metrecia L

    2009-08-01

    Full Text Available Abstract Background Polybrominated biphenyl (PBB, a brominated flame retardant, was accidently mixed into animal feed in Michigan (1973–1974 resulting in human exposure through consumption of contaminated meat, milk and eggs. Beginning in 1976 individuals who consumed contaminated products were enrolled in the Michigan Long-Term PBB Study. This cohort presents a unique opportunity to study the association between parental exposures to PBB and offspring sex ratio. Methods We identified offspring of female PBB cohort participants (born 1975–1988 and obtained electronic birth records for those born in the state of Michigan. We linked this information to parental serum PBB and PCB concentrations collected at enrollment into the cohort. We modeled the odds of a male birth with generalized estimating equations accounting for the non-independence of siblings born to the same parents. We explored potential confounders: parental age and education at offspring's birth, parental body mass index at cohort enrollment, birth order, gestational age and year of offspring's birth. Results The overall proportion of male offspring among 865 live births to cohort mothers was 0.542. This was higher than the national male proportion of 0.514 (binomial test: p = 0.10. When both parents were in the cohort (n = 300, we found increased odds of a male birth with combined parents' enrollment PBB exposure ≥ the median concentrations (3 μg/L for mothers; 6 μg/L for fathers compared to combined parents' PBB exposure Conclusion This study adds to the body of literature on secondary sex ratio and exposure to environmental contaminants. In this population, combined parental exposure to PBBs or PCBs increased the odds of a male birth. Further research is needed to corroborate these findings and shed light on the biological mechanisms by which these types of chemicals may influence the secondary sex ratio.

  7. Sex-Specific Patterns of Aberrant Brain Function in First-Episode Treatment-Naive Patients with Schizophrenia.

    Science.gov (United States)

    Lei, Wei; Li, Mingli; Deng, Wei; Zhou, Yi; Ma, Xiaohong; Wang, Qiang; Guo, Wanjun; Li, Yinfei; Jiang, Lijun; Han, Yuanyuan; Huang, Chaohua; Hu, Xun; Li, Tao

    2015-07-16

    Male and female patients with schizophrenia show significant differences in a number of important clinical features, yet the neural substrates of these differences are still poorly understood. Here we explored the sex differences in the brain functional aberrations in 124 treatment-naïve patients with first-episode schizophrenia (61 males), compared with 102 age-matched healthy controls (50 males). Maps of degree centrality (DC) and amplitude of low-frequency fluctuations (ALFF) were constructed using resting-state functional magnetic resonance imaging data and compared between groups. We found that: (1) Selective DC reduction was observed in the right putamen (Put_R) in male patients and the left middle frontal gyrus (MFG) in female patients; (2) Functional connectivity analysis (using Put_R and MFG as seeds) found that male and female patients have disturbed functional integration in two separate networks, i.e., the sensorimotor network and the default mode network; (3) Significant ALFF alterations were also observed in these two networks in both genders; (4) Sex specific brain functional alterations were associated with various symptoms in patients. These results suggested that sex-specific patterns of functional aberration existed in schizophrenia, and these patterns were associated with the clinical features both in male and female patients.

  8. Sex-Specific Patterns of Aberrant Brain Function in First-Episode Treatment-Naive Patients with Schizophrenia

    Directory of Open Access Journals (Sweden)

    Wei Lei

    2015-07-01

    Full Text Available Male and female patients with schizophrenia show significant differences in a number of important clinical features, yet the neural substrates of these differences are still poorly understood. Here we explored the sex differences in the brain functional aberrations in 124 treatment-naïve patients with first-episode schizophrenia (61 males, compared with 102 age-matched healthy controls (50 males. Maps of degree centrality (DC and amplitude of low-frequency fluctuations (ALFF were constructed using resting-state functional magnetic resonance imaging data and compared between groups. We found that: (1 Selective DC reduction was observed in the right putamen (Put_R in male patients and the left middle frontal gyrus (MFG in female patients; (2 Functional connectivity analysis (using Put_R and MFG as seeds found that male and female patients have disturbed functional integration in two separate networks, i.e., the sensorimotor network and the default mode network; (3 Significant ALFF alterations were also observed in these two networks in both genders; (4 Sex specific brain functional alterations were associated with various symptoms in patients. These results suggested that sex-specific patterns of functional aberration existed in schizophrenia, and these patterns were associated with the clinical features both in male and female patients.

  9. 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

  10. Verbal communication about sex in marriage: patterns of language use and its connection with relational outcomes.

    Science.gov (United States)

    Hess, Jon A; Coffelt, Tina A

    2012-01-01

    This study examined the vocabulary husbands and wives use for talking to each other about sex, and connections between language use and relational qualities. Married people (n = 293) responded to a questionnaire about their use of common sex-related terms and about several characteristics of their marriage: sexual communication satisfaction, relational satisfaction, and relational closeness. Cluster analysis based on reported use revealed that sexual terms fell into clusters characterized as clinical terms, slang, or standard English. Results showed an association between use of sexual terms, particularly slang terms, and both satisfaction and closeness. This connection was stronger for women than for men. The findings offer insight into sexual talk and marital relationships.

  11. Task Selection is Critical for the Demonstration of Reciprocal Patterns of Sex Differences in Hand/Arm Motor Control and Near/Far Visual Processing

    Directory of Open Access Journals (Sweden)

    Geoff Sanders

    2008-04-01

    Full Text Available Women have been reported to perform better with hand rather than arm movements (Sanders and Walsh, 2007 and with visual stimuli in near rather than far space (Sanders, Sinclair and Walsh, 2007. Men performed better with the arm and in far space. These reciprocal patterns of sex differences appear as Muscle*Sex and Space*Sex interactions. We investigated these claims using target cancellation tasks in which task difficulty was manipulated by varying target size or the number of distracters. In Study 1 we did not find the Muscle*Sex or the Space*Sex interaction. We argue that ballistic movement was too simple to reveal the Muscle*Sex interaction. However, a trend for the Space*Sex interaction suggested task difficulty was set too high. Study 2 introduced easier levels of difficulty and the overall Space*Sex interaction narrowly failed to reach significance (p = 0.051. In Study 3 the Space*Sex interaction was significant (p = 0.001. A review of the present, and four previously published, studies indicates that task selection is critical if the Space*Sex interaction and its associated reciprocal within-sex differences are to be demonstrated without the obscuring effects of Space and Difficulty. These sex differences are compatible with predictions from the hunter-gatherer hypothesis. Implications for two-visual-system-models are considered.

  12. HIV infection among foreign transsexual sex workers in Rome: prevalence, behavior patterns, and seroconversion rates.

    Science.gov (United States)

    Spizzichino, L; Zaccarelli, M; Rezza, G; Ippolito, G; Antinori, A; Gattari, P

    2001-07-01

    The Azienda Sanitaria Locale Roma E (ASL-RME) outpatient clinic is the main reference center in Rome for HIV testing of foreign people. To define the prevalence and incidence of HIV infection among foreign transsexual sex workers attending the center. A cross-sectional, follow-up study was conducted. Between 1993 and 1999, 353 transsexuals attended the ASL-RME. They were from Colombia (n = 208), Brazil (n = 122), and other countries (n = 23). Most of these transsexuals reported having 5 to 10 partners per day. The overall HIV prevalence was 38.2%, which multivariate analysis found to be associated with origin from Brazil and a higher number of sex partners. The observed HIV seroconversion rate was 4.1 per 100 person-years, and non-regular condom use was the only factor related to seroconversion. The data from this study suggest that promotion of safer sex practices and regular condom use still is the main priority among marginalized population subgroups, such as foreign prostitutes, involved in sex activities that put them at risk for HIV infection.

  13. Sex and Race Disparities in Health: Cohort Variations in Life Course Patterns

    Science.gov (United States)

    Yang, Yang; Lee, Linda C.

    2009-01-01

    This study assesses changes in sex and race disparities in health over the life course and across cohorts by conducting growth curve analyses of nationally representative longitudinal data that spans 15 years. It finds that changes in disparities in depressive symptoms, disability and self-assessments of health across the life course are…

  14. Cell adhesion molecules expression pattern indicates that somatic cells arbitrate gonadal sex of differentiating bipotential fetal mouse gonad.

    Science.gov (United States)

    Piprek, Rafal P; Kolasa, Michal; Podkowa, Dagmara; Kloc, Malgorzata; Kubiak, Jacek Z

    2017-10-01

    Unlike other organ anlagens, the primordial gonad is sexually bipotential in all animals. In mouse, the bipotential gonad differentiates into testis or ovary depending on the genetic sex (XY or XX) of the fetus. During gonad development cells segregate, depending on genetic sex, into distinct compartments: testis cords and interstitium form in XY gonad, and germ cell cysts and stroma in XX gonad. However, our knowledge of mechanisms governing gonadal sex differentiation remains very vague. Because it is known that adhesion molecules (CAMs) play a key role in organogenesis, we suspected that diversified expression of CAMs should also play a crucial role in gonad development. Using microarray analysis we identified 129 CAMs and factors regulating cell adhesion during sexual differentiation of mouse gonad. To identify genes expressed differentially in three cell lines in XY and XX gonads: i) supporting (Sertoli or follicular cells), ii) interstitial or stromal cells, and iii) germ cells, we used transgenic mice expressing EGFP reporter gene and FACS cell sorting. Although a large number of CAMs expressed ubiquitously, expression of certain genes was cell line- and genetic sex-specific. The sets of CAMs differentially expressed in supporting versus interstitial/stromal cells may be responsible for segregation of these two cell lines during gonadal development. There was also a significant difference in CAMs expression pattern between XY supporting (Sertoli) and XX supporting (follicular) cells but not between XY and XX germ cells. This indicates that differential CAMs expression pattern in the somatic cells but not in the germ line arbitrates structural organization of gonadal anlagen into testis or ovary. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. The spatial patterns of water management practices are reflected in the strontium isotope ratios of human hair

    Science.gov (United States)

    Tipple, B. J.; Valenzuela, L. O.; Ehleringer, J.

    2012-12-01

    Element concentrations and isotopes of human tissues are commonly used to understand how emissions and processes within urban ecosystems affect health. Thus, it is important to understand how these elements are incorporated and flow through the urban environment and are ultimately incorporated into human tissues. Here, we designed an experiment to identify the relative importance of strontium (Sr) sources (bedrock, dust, food, and water) to hair Sr isotope ratios (87Sr/86Sr). To understand the contribution of Sr to human hair, we collected hair from individuals living in Salt Lake City, Utah. In addition to sample location, we compiled information regarding age, sex, ethnicity, and dietary habits. We found a significant association between 87Sr/86Sr value of hair and collection location. There were no significant relationships between 87Sr/86Sr value of hair and age, ethnicity, or sex. We had not predicted a relationship between 87Sr/86Sr values and collection location, because of the close proximities of sites to one another (all within an 8-km radius). We found that tap water 87Sr/86Sr values across the Salt Lake Valley varied with water management practice and this variation corresponded to hair 87Sr/86Sr value. These data suggest an additional geographically controlled source of Sr may be an important contributor to the 87Sr/86Sr value of hair. These findings suggest that local water is an important source of Sr in human hair and that hair is a sensitive temporal carrier of this environmental information. These observations have important implications to future studies of humans with regard to urban ecology, human health, forensic sciences, and anthropology.

  16. Does the radiation from the interim storage in Gorleben affect the sex ratio of newborn children?; Beeinflusst die Strahlung aus dem Zwischenlager in Gorleben das Geschlechterverhaeltnis von Neugeborenen?

    Energy Technology Data Exchange (ETDEWEB)

    Engelmann, H.W.; Schulze, H.; Wede, S. [GNS Gesellschaft fuer Nuklear-Service mbH, Gorleben (Germany); Mueller, S. [Studsvik GmbH, Pforzheim (Germany)

    2015-07-01

    In the professional world but especially in public, the question is discussed whether ionizing radiation from nuclear facilities has a significant impact on the secondary sex ratio of newborn children in the vicinity of the plants. This issue is of exceptional importance in the region around Gorleben, where the opposition to nuclear facilities and activities for decades is particularly strong. At the site borders of the interim storage facility (TBL-G) of GNS the effective individual dose is about 0.2 mSv per year, mainly caused by neutron irradiation from 108 casks with high-level radioactive waste from reprocessing. In the surrounding villages there is no radiation measurable. Statistical studies allegedly have shown evidence that in some villages in the area and during certain periods, proportionately fewer girls were born in comparison to the average for the Federal Republic of Germany. Based on these purely statistical results henceforward was also alleged that neutron-induced secondary effects such as activation or secondary gamma radiation would be responsible for it. Monte Carlo calculations and special measurements yielded values of the dose at the plant border for activation products less than E-04 mSv/a and for secondary gamma radiation of about E-03 mSv/a. These results indicate that the ionizing radiation from the Gorleben interim storage facility cannot be held accountable for shifts of the secondary sex ratio.

  17. Socioeconomic status and sex ratios at birth in Sweden: No evidence for a Trivers-Willard effect for a wide range of status indicators.

    Science.gov (United States)

    Kolk, Martin; Schnettler, Sebastian

    2016-01-01

    This study examines if there exists a positive association between socioeconomic status and the proportion of male births in humans, as proposed by Trivers and Willard in 1973, using individual-level data drawn from the complete population of Sweden. We examine more than 3,000,000 births between 1960 and 2007 using administrative register data with comprehensive information on various dimensions of socioeconomic status. We use six different operationalizations of socioeconomic status, including earnings, post-transfer income (including government allowances), wealth, parental wealth, educational level, and occupational class. We apply regression models that compare both changes in status for the same woman over time and differences in status across different women. We also measure socioeconomic status both at the year of child birth and the year of conception. Our results show the absence of any relationship between socioeconomic status and sex ratios, using a large number of different operationalizations of status. We conclude that no substantive relationship between socioeconomic status and sex ratios exists for the population and period of our study. © 2015 Wiley Periodicals, Inc.

  18. Sex ratio at birth: scenario from normal- and high-level natural radiation areas of Kerala coast in south-west India

    International Nuclear Information System (INIS)

    Koya, P.K.M.; Jaikrishan, G.; Sudheer, K.R.; Madhusoodhanan, M.; Jagadeesan, C.K.; Das, Birajalaxmi; Andrews, V.J.

    2015-01-01

    Newborns were monitored for congenital malformations in four government hospitals located in high-level (ambient dose >1.5 mGy/year) and normal-level (≤1.5 mGy/year) natural radiation areas of Kerala, India, from August 1995 to December 2012. Sex ratio at birth (SRB) among live singleton newborns and among previous children, if any, of their mothers without history of any abortion, stillbirth or twins is reported here. In the absence of environmental stress or selective abortion of females, global average of SRB is about 1050 males to 1000 females. A total of 151,478 singleton, 1031 twins, 12 triplets and 1 quadruplet deliveries were monitored during the study period. Sex ratio among live singleton newborns was 1046 males (95 % CI 1036-1057) for 1000 females (77,153 males:73,730 females) and was comparable to the global average. It was similar in high-level and normal-level radiation areas of Kerala with SRB of 1050 and 1041, respectively. It was consistently more than 1000 and had no association with background radiation levels, maternal and paternal age at birth, parental age difference, gravida status, ethnicity, consanguinity or year of birth. Analysis of SRB of the children of 139,556 women whose reproductive histories were available suggested that couples having male child were likely to opt for more children and this, together with enhanced rate of males at all birth order, was skewing the overall SRB in favour of male children. Though preference for male child was apparent, extreme steps of sex-selective abortion or infanticide were not prevalent. (orig.)

  19. 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.

  20. Sex ratio at birth: scenario from normal- and high-level natural radiation areas of Kerala coast in south-west India

    Energy Technology Data Exchange (ETDEWEB)

    Koya, P.K.M.; Jaikrishan, G.; Sudheer, K.R. [Bhabha Atomic Research Centre, Low Level Radiation Research Laboratory, Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Kollam (India); Madhusoodhanan, M. [Victoria Hospital, Department of Paediatrics, Kollam (India); Jagadeesan, C.K. [Directorate of Health Services, Thiruvananthapuram (India); Das, Birajalaxmi [Bhabha Atomic Research Centre, Low Level Radiation Research Section, Radiation Biology and Health Sciences Division, Bio-Science Group, Mumbai (India); Andrews, V.J.

    2015-11-15

    Newborns were monitored for congenital malformations in four government hospitals located in high-level (ambient dose >1.5 mGy/year) and normal-level (≤1.5 mGy/year) natural radiation areas of Kerala, India, from August 1995 to December 2012. Sex ratio at birth (SRB) among live singleton newborns and among previous children, if any, of their mothers without history of any abortion, stillbirth or twins is reported here. In the absence of environmental stress or selective abortion of females, global average of SRB is about 1050 males to 1000 females. A total of 151,478 singleton, 1031 twins, 12 triplets and 1 quadruplet deliveries were monitored during the study period. Sex ratio among live singleton newborns was 1046 males (95 % CI 1036-1057) for 1000 females (77,153 males:73,730 females) and was comparable to the global average. It was similar in high-level and normal-level radiation areas of Kerala with SRB of 1050 and 1041, respectively. It was consistently more than 1000 and had no association with background radiation levels, maternal and paternal age at birth, parental age difference, gravida status, ethnicity, consanguinity or year of birth. Analysis of SRB of the children of 139,556 women whose reproductive histories were available suggested that couples having male child were likely to opt for more children and this, together with enhanced rate of males at all birth order, was skewing the overall SRB in favour of male children. Though preference for male child was apparent, extreme steps of sex-selective abortion or infanticide were not prevalent. (orig.)

  1. The effects of bis(tributyltin) oxide on the development, reproduction and sex ratio of calanoid copepod Pseudodiaptomus marinus

    Science.gov (United States)

    Huang, Ying; Zhu, Liyan; Liu, Guangxing

    2006-08-01

    In order to study the biological effects by bis(tributyltin) oxide (TBTO) exposure, chronic toxicity tests were conducted on the calanoid copepod Pseudodiaptomus marinus over two generations. The results indicated that nauplii were more sensitive than copepodites. F1 copepods were more vulnerable than F0 copepods and a drastic increase in mortality was observed as the TBTO concentration became higher. Exposure of copepods to 60 ng l -1 TBTO concentration reduced the fecundity and resulted in some females being infecund (in the F0 generation). The time to the first egg sac for females in the F1 generation exposed to 6 ng l -1 TBTO concentration was significantly reduced, and the fecundity of this generation was increased. The female-to-male ratio in the F1 generation exposed to 20 ng l -1 TBTO concentration was significantly reduced. These results show that the current ambient TBT concentration may influence populations of copepods in the coastal environment.

  2. Secular Trends and Latitude Gradients in Sex Ratios at Birth in Czechoslovakia and the Post-Czechoslovakian States

    Directory of Open Access Journals (Sweden)

    Victor Grech

    2012-01-01

    Full Text Available Latitude gradients and secular trends in Europe and North America have been found in the male-female ratio at birth (M/F: male births divided by total births which is expected to be 0.515. Annual national data for Czechoslovakia and the post-Czechoslovakian (Czech Republic and Slovakia countries for male and female live births were obtained from the World Health Organisation and analysed with contingency tables. This study analysed 13,123,538 live births. An overall decreasing trend in M/F was found (p < 00001. No latitude gradient was noted. There was an overall deficit of 15,232 male births based on an M/F of 0.515. M/F is declining in this region, despite well developing economies that have resisted the worldwide slowdown. An interplay of several poorly understood factors is likely.

  3. Flow patterns and heat transfer characteristics of flat plate pulsating heat pipes with various asymmetric and aspect ratios of the channels

    International Nuclear Information System (INIS)

    Jang, Dong Soo; Lee, Joo Seong; Ahn, Jae Hwan; Kim, Dongwoo; Kim, Yongchan

    2017-01-01

    Highlights: • Flat plate pulsating heat pipes with asymmetric and aspect ratios were tested. • Flow patterns were investigated according to channel geometry and flow condition. • Heat transfer characteristics were analyzed with various heat inputs. • Optimum asymmetric and aspect ratios were suggested for maximum thermal performance. - Abstract: The thermal performance of flat plate pulsating heat pipes (PHPs) in compact electronic devices can be improved by adopting asymmetric channels with increased pressure differences and an unbalanced driving force. The objective of this study is to investigate the heat transfer characteristics of flat plate PHPs with various asymmetric ratios and aspect ratios in the channels. The thermal performance and flow pattern of the flat plate PHPs were measured by varying the asymmetric ratio from 1.0 to 4.0, aspect ratio from 2.5 to 5.0, and heat input from 2 to 28 W. The effects of the asymmetric ratio and aspect ratio on the thermal resistance were analyzed with the measured evaporator temperature and flow patterns at various heat inputs. With heat inputs of 6 W and 12 W, the optimum asymmetric ratio and aspect ratio for the flat plate PHPs were determined to be 4.0 and 2.5, respectively. With the heat input of 18 W, the optimum asymmetric ratio and aspect ratio were determined to be 1.5 and 2.5, respectively.

  4. Effects of long term feeding of Quillaja saponins on sex ratio, muscle and serum cholesterol and LH levels in Nile tilapia (Oreochromis niloticus (L)).

    Science.gov (United States)

    Francis, George; Levavi-Sivan, Berta; Avitan, Ayelet; Becker, Klaus

    2002-12-01

    Seventeen-day-old Nile tilapia fry were fed a standard diet (C) or diets containing 50-700 mg kg(-1) Quillaja saponin (QS) extract (groups S50, S150, S300, S500 and S700). After the first 8 weeks, 30 randomly selected tilapia from each of the treatments were placed in separate aquaria and fed the standard diet without saponins from then on (these were designated S50/C, S150/C, S300/C, S500/C and S700/C). The fish grew from an initial average weight of approximately 30 mg to a final average weight of 79 g during the 6-month feeding period. The difference between the average weight of C-fed tilapia and the treatment with the highest average weight after 6 months was 53.5%. The sex ratio of tilapia in the saponin-fed groups deviated from the normal 50:50 male:female ratio, with the S700 group showing a significantly higher number of males. Quillaja saponin stimulated LH release from dispersed tilapia pituitary cells in vitro. This effect was abolished in the presence of dilute calf serum. Serum LH values did not show any diet-dependent trend in either male or female tilapia in vivo. In both continuously saponin-fed and only-initially saponin-fed groups, the average serum (but not muscle) cholesterol levels in males showed an increasing trend (R(2) values of 0.62 and 0.69) with increasing dietary saponin level. It was concluded that dietary QS has the potential to change the sex-ratio in favour of males. More investigations are required to determine the mechanism of action and the optimum dietary level of QS for maximum effects.

  5. ACC oxidase and miRNA 159a, and their involvement in fresh fruit bunch yield (FFB) via sex ratio determination in oil palm.

    Science.gov (United States)

    Somyong, Suthasinee; Poopear, Supannee; Sunner, Supreet Kaur; Wanlayaporn, Kitti; Jomchai, Nukoon; Yoocha, Thippawan; Ukoskit, Kittipat; Tangphatsornruang, Sithichoke; Tragoonrung, Somvong

    2016-06-01

    Oil palm (Elaeis guineesis Jacq.) is the most productive oil-bearing crop, yielding more oil per area than any other oil-bearing crops. However, there are still efforts to improve oil palm yield, in order to serve consumer and manufacturer demand. Oil palm produces female and male inflorescences in an alternating cycle. So, high sex ratio (SR), the ratio of female inflorescences to the total inflorescences, is a favorable trait in term of increasing yields in oil palm. This study aims to understand the genetic control for SR related traits, such as fresh fruit bunch yield (FFB), by characterizing genes at FFB quantitative trait loci (QTLs) on linkage 10 (chromosome 6) and linkage 15 (chromosome 10). Published oil palm sequences at the FFB QTLs were used to develop gene-based and simple sequence repeat (SSR) markers. We used the multiple QTL analysis model (MQM) to characterize the relationship of new markers with the SR traits in the oil palm population. The RNA expression of the most linked QTL genes was also evaluated in various tissues of oil palm. We identified EgACCO1 (encoding aminocyclopropane carboxylate (ACC) oxidase) at chromosome 10 and EgmiR159a (microRNA 159a) at chromosome 6 to be the most linked QTL genes or determinants for FFB yield and/or female inflorescence number with a phenotype variance explained (PVE) from 10.4 to 15 % and suggest that these play the important roles in sex determination and differentiation in oil palm. The strongest expression of EgACCO1 and the predicted precursor of EgmiR159a was found in ovaries and, to a lesser extent, fruit development. In addition, highly normalized expression of EgmiR159a was found in female flowers. In summary, the QTL analysis and the RNA expression reveal that EgACCO1 and EgmiR159a are the potential genetic factors involved in female flower determination and hence would affect yield in oil palm. However, to clarify how these genetic factors regulate female flower determination, more investigation

  6. 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

  7. 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.

  8. Sex-specific patterns of morphological diversification: evolution of reaction norms and static allometries in neriid flies.

    Science.gov (United States)

    Cassidy, Elizabeth J; Bath, Eleanor; Chenoweth, Stephen F; Bonduriansky, Russell

    2014-02-01

    The consequences of sex-specific selection for patterns of diversification remain poorly known. Because male secondary sexual traits are typically costly to express, and both costs and benefits are likely to depend on ambient environment and individual condition, such traits may be expected to diversify via changes in reaction norms as well as the scaling of trait size with body size (static allometry). We investigated morphological diversification within two species of Australian neriid flies (Telostylinus angusticollis, Telostylinus lineolatus) by rearing larvae from several populations on larval diets varying sixfold in nutrient concentration. Mean body size varied among populations of T. angusticollis, but body size reaction norms did not vary within either species. However, we detected diversification of reaction norms for body shape in males and females within both species. Moreover, unlike females, males also diversified in static allometry slope and reaction norms for static allometry slope of sexual and nonsexual traits. Our findings reveal qualitative sex differences in patterns of morphological diversification, whereby shape-size relationships diversify extensively in males, but remain conserved in females despite extensive evolution of trait means. Our results highlight the importance of incorporating plasticity and allometry in studies of adaptation and diversification. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

  9. Stable nitrogen isotope analysis of dentine serial sections elucidate sex differences in weaning patterns of wild chimpanzees (Pan troglodytes).

    Science.gov (United States)

    Fahy, Geraldine E; Richards, Michael P; Fuller, Benjamin T; Deschner, Tobias; Hublin, Jean-Jacques; Boesch, Christophe

    2014-04-01

    Offspring provisioning is one of the most energetically demanding aspects of reproduction for female mammals. Variation in lactation length and weaning strategies between chimpanzees (Pan troglodytes), our closest living relative, and modern human societies have been reported. When and why these changes occurred is frequently debated. Our study used stable nitrogen isotope data of tooth root dentine from wild Western chimpanzees (Pan troglodytes verus) in Taï National Park, Côte d'Ivoire, to quantify weaning in these chimpanzees and explore if infant sex plays a role in maternal investment. We analyzed serial sections of deciduous lateral incisor root dentine from four Taï chimpanzees to establish the δ(15) N signal of nursing infants; we then analyzed serial sections of first permanent mandibular molar root dentine from 12 Taï chimpanzees to provide quantitative δ(15) N data on weaning in this population. Up to 2 years of age both sexes exhibited dentine δ(15) N values ≈2-3‰ higher than adult female Taï chimpanzees, consistent with a nursing signal. Thereafter a steady decrease in δ(15) N values consistent with the onset, and progression, of weaning, was visible. Sex differences were also evident, where male δ(15) N values decreased at a significantly slower rate compared to females. Confirmation of sex differences in maternal investment among Taï chimpanzees, demonstrates the viability of using isotope analysis to investigate weaning in non-human primates. Additionally, assuming that behaviors observed in the Taï chimpanzees are illustrative of the ancestral pattern, our results provide a platform to enable the trajectory of weaning in human evolution to be further explored. Copyright © 2013 Wiley Periodicals, Inc.

  10. Age- and sex-specific mortality patterns in an emerging wildlife epidemic: the phocine distemper in European harbour seals.

    Directory of Open Access Journals (Sweden)

    Tero Härkönen

    Full Text Available Analyses of the dynamics of diseases in wild populations typically assume all individuals to be identical. However, profound effects on the long-term impact on the host population can be expected if the disease has age and sex dependent dynamics. The Phocine Distemper Virus (PDV caused two mass mortalities in European harbour seals in 1988 and in 2002. We show the mortality patterns were highly age specific on both occasions, where young of the year and adult (>4 yrs animals suffered extremely high mortality, and sub-adult seals (1-3 yrs of both sexes experienced low mortality. Consequently, genetic differences cannot have played a main role explaining why some seals survived and some did not in the study region, since parents had higher mortality levels than their progeny. Furthermore, there was a conspicuous absence of animals older than 14 years among the victims in 2002, which strongly indicates that the survivors from the previous disease outbreak in 1988 had acquired and maintained immunity to PDV. These specific mortality patterns imply that contact rates and susceptibility to the disease are strongly age and sex dependent variables, underlining the need for structured epidemic models for wildlife diseases. Detailed data can thus provide crucial information about a number of vital parameters such as functional herd immunity. One of many future challenges in understanding the epidemiology of the PDV and other wildlife diseases is to reveal how immune system responses differ among animals in different stages during their life cycle. The influence of such underlying mechanisms may also explain the limited evidence for abrupt disease thresholds in wild populations.

  11. Sex-differentiated migration patterns, protandry and phenology in North European songbird populations

    DEFF Research Database (Denmark)

    Tøttrup, Anders Peter; Thorup, Kasper

    2008-01-01

    with the largest change for the first arriving individuals. These findings seem in support of the "mate opportunity" hypothesis, as the arrival of males and females is strongly coupled and both sexes seem to compete for early arrival. Changes in timing of arrival in males and females as a response to climatic...... changes may influence subsequent mating decisions, with subsequent feedbacks on population dynamics such as reproductive success and individual fitness. However, during decades of consistent earlier spring arrival in all phases of migration we found no evidence of inter-sexual phenological differences....

  12. Application of sulphur isotope ratios to examine weaning patterns and freshwater fish consumption in Roman Oxfordshire, UK

    Science.gov (United States)

    Nehlich, Olaf; Fuller, Benjamin T.; Jay, Mandy; Mora, Alice; Nicholson, Rebecca A.; Smith, Colin I.; Richards, Michael P.

    2011-09-01

    This study investigates the application of sulphur isotope ratios (δ 34S) in combination with carbon (δ 13C) and nitrogen (δ 15N) ratios to understand the influence of environmental sulphur on the isotopic composition of archaeological human and faunal remains from Roman era sites in Oxfordshire, UK. Humans ( n = 83), terrestrial animals ( n = 11), and freshwater fish ( n = 5) were analysed for their isotope values from four locations in the Thames River Valley, and a broad range of δ 34S values were found. The δ 34S values from the terrestrial animals were highly variable (-13.6‰ to +0.5‰), but the δ 34S values of the fish were clustered and 34S-depleted (-20.9‰ to -17.3‰). The results of the faunal remains suggest that riverine sulphur influenced the terrestrial sulphur isotopic signatures. Terrestrial animals were possibly raised on the floodplains of the River Thames, where highly 34S-depleted sulphur influenced the soil. The humans show the largest range of δ 34S values (-18.8‰ to +9.6‰) from any archaeological context to date. No differences in δ 34S values were found between the males (-7.8 ± 6.0‰) and females (-5.3 ± 6.8‰), but the females had a linear correlation ( R2 = 0.71; p eating solely terrestrial protein resources and others showing a diet almost exclusively based on freshwater protein such as fish. Such large dietary variability was not visible by analysing only the carbon and nitrogen isotope ratios, and this research represents the largest and most detailed application of δ 34S analysis to examine dietary practices (including breastfeeding and weaning patterns) during the Romano-British Period.

  13. Signal-to-noise ratio of bilateral nonimaging transcranial Doppler recordings of the middle cerebral artery is not affected by age and sex.

    Science.gov (United States)

    Katsogridakis, Emmanuel; Dineen, Nicky E; Brodie, Fiona G; Robinson, Thompson G; Panerai, Ronney B

    2011-04-01

    Differences between transcranial Doppler ultrasonography (TCD) recordings of symmetrical vessels can show true physiologic differences, but can also be caused by measurement error and other sources of noise. The aim of this project was to assess the influence of noise on estimates of dynamic cerebral autoregulation (dCA), and of age, sex and breathing manoeuvres on the signal-to-noise ratio (SNR). Cerebral blood flow (CBF) was monitored in 30 young (60 years) during baseline conditions, breath-holding and hyperventilation. Noise was defined as the difference between beat-to-beat values of the two mean CBF velocity (CBFV) signals. Magnitude squared coherence estimates of noise vs. ABP and ABP vs. CBFV were obtained and averaged. A similar approach was adopted for the CBFV step response. The effect of age and breathing manoeuvre on the SNR was assessed using a two-way analysis of variance (ANOVA), whilst the effect of sex was investigated using a Student's t test. No significant differences were observed in SNR (baseline 6.07 ± 3.07 dB and 7.33 ± 3.84 dB, breath-hold: 13.53 ± 3.93 dB and 14.64 ± 4.52 dB, and hyperventilation: 14.69 ± 4.04 dB and 14.84 ± 4.05 dB) estimates between young and old groups, respectively. The use of breathing manoeuvres significantly improved the SNR (p < 10(-4)) without a significant difference between manoeuvres. Sex does not appear to have an effect on SNR (p = 0.365). Coherence estimates were not influenced by the SNR, but significant differences were found in the amplitude of the CBFV step response. Copyright © 2011 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  14. 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.

  15. Predicting the variation in Echinogammarus marinus at its southernmost limits under global warming scenarios: can the sex-ratio make a difference?

    Science.gov (United States)

    Guerra, Alexandra; Leite, Nuno; Marques, João Carlos; Ford, Alex T; Martins, Irene

    2014-01-01

    Understanding the environmental parameters that constrain the distribution of a species at its latitudinal extremes is critical for predicting how ecosystems react to climate change. Our first aim was to predict the variation in the amphipod populations of Echinogammarus marinus from the southernmost limit of its distribution under global warming scenarios. Our second aim was to test whether sex-ratio fluctuations - a mechanism frequently displayed by amphipods - respond to the variations in populations under altered climate conditions. To achieve these aims, scenarios were run with a validated model of E. marinus populations. Simulations were divided into: phase I - simulation of the effect of climate change on amphipod populations, and phase II - simulation of the effect of climate change on populations with male and female proportions. In both phases, temperature (T), salinity (S) and temperature and salinity (T-S) were tested. Results showed that E. marinus populations are highly sensitive to increases in temperature (>2 °C), which has adverse effects on amphipod recruitment and growth. Results from the climate change scenarios coupled with the sex-ratio fluctuations depended largely on the degree of female bias within population. Temperature increase of 2 °C had less impact on female-biased populations, particularly when conjugated with increases in salinity. Male-biased populations were highly sensitive to any variation in temperature and/or salinity; these populations exhibited a long-term decline in density. Simulations in which temperature increased more than 4 °C led to a continuous decline in the E. marinus population. According to this work, E. marinus populations at their southernmost limit are vulnerable to global warming. We anticipate that in Europe, temperature increases of 2 °C will incite a withdrawal of the population of 5°N from the amphipod species located at southernmost geographical borders. This effect is discussed in relation to the

  16. Temporal expression pattern of genes during the period of sex differentiation in human embryonic gonads

    DEFF Research Database (Denmark)

    Mamsen, Linn S; Ernst, Emil H; Borup, Rehannah

    2017-01-01

    The precise timing and sequence of changes in expression of key genes and proteins during human sex-differentiation and onset of steroidogenesis was evaluated by whole-genome expression in 67 first trimester human embryonic and fetal ovaries and testis and confirmed by qPCR and immunohistochemistry...... (IHC). SRY/SOX9 expression initiated in testis around day 40 pc, followed by initiation of AMH and steroidogenic genes required for androgen production at day 53 pc. In ovaries, gene expression of RSPO1, LIN28, FOXL2, WNT2B, and ETV5, were significantly higher than in testis, whereas GLI1...... was significantly higher in testis than ovaries. Gene expression was confirmed by IHC for GAGE, SOX9, AMH, CYP17A1, LIN28, WNT2B, ETV5 and GLI1. Gene expression was not associated with the maternal smoking habits. Collectively, a precise temporal determination of changes in expression of key genes involved in human...

  17. Sex differences in functional activation patterns revealed by increased emotion processing demands.

    Science.gov (United States)

    Hall, Geoffrey B C; Witelson, Sandra F; Szechtman, Henry; Nahmias, Claude

    2004-02-09

    Two [O(15)] PET studies assessed sex differences regional brain activation in the recognition of emotional stimuli. Study I revealed that the recognition of emotion in visual faces resulted in bilateral frontal activation in women, and unilateral right-sided activation in men. In study II, the complexity of the emotional face task was increased through tje addition of associated auditory emotional stimuli. Men again showed unilateral frontal activation, in this case to the left; whereas women did not show bilateral frontal activation, but showed greater limbic activity. These results suggest that when processing broader cross-modal emotional stimuli, men engage more in associative cognitive strategies while women draw more on primary emotional references.

  18. Sex-specific sleep patterns among university students in Lebanon: impact on depression and academic performance

    OpenAIRE

    Kabrita, Colette S; Hajjar-Mu?a, Theresa A

    2016-01-01

    Colette S Kabrita,1 Theresa A Hajjar-Muça,2 1Department of Sciences, 2Department of Mathematics and Statistics, Faculty of Natural and Applied Sciences, Notre Dame University – Louaize, Zouk Mosbeh, Lebanon Abstract: Good sleep quality and quantity are fundamental to the maintenance of normal physiological processes. Changes in sleep patterns are commonly observed among young adults and are shown to impact neurocognitive, academic, and psychological well-being. Given the ...

  19. 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

    DEFF Research Database (Denmark)

    Søeborg, Tue; Frederiksen, Hanne; Mouritsen, Annette

    2014-01-01

    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....... 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...

  20. Antibiotic prophylaxis among commercial sex workers in Cebu City, Philippines. Patterns of use and perceptions of efficacy.

    Science.gov (United States)

    Abellanosa, I; Nichter, M

    1996-01-01

    This study describes the extent to which commercial sex workers (CSW) in Cebu City, Philippines perceive prophylactic antibiotic use to be an effective form of prevention for sexually transmitted diseases (STD) and human immunodeficiency virus (HIV), as well as the prevalence of this self-treatment practice. A survey instrument was developed and pretested after 3 months of intensive ethnographic research on STD and acquired immune deficiency syndrome (AIDS). A multistage sampling procedure was followed to ensure that a representative sample of CSW from four distinct work environments would be interviewed. Commercial sex workers registered at the Cebu City social hygiene clinic were sampled randomly from coded work establishment lists, and a convenience sample of unregistered freelance CSW was secured. In total, 200 CSW were interviewed. Of these 200 CSW, all were sexually active, but only 160 had been engaged actively in commercial sexual exchange the month before their interviews. Popular use of antibiotics as prophylaxis against STD is commonplace in the Philippines among CSW, with 38% reporting routine or occasional use and 31% reporting use in the last 2 weeks. Unregistered CSW are five times more likely to use prophylactic antibiotics than registered CSW, and they are seven times less likely to use condoms with 80% or more of their customers. They also have sex with three times as many customers. Use of prophylactic antibiotics by CSW offers them a false sense of security in a high-risk work environment. Self-treatment with low-dose prophylactic antibiotics provides no protection against STD, impedes STD screening efforts, and contributes to antibiotic resistance. An alarming percentage of CSW consider antibiotics a potential means of protecting themselves against AIDS. Public health interventions focusing on STD and AIDS in developing countries must address current patterns of prophylactic antibiotic use.

  1. The effect of PCSK1 variants on waist, waist-hip ratio and glucose metabolism is modified by sex and glucose tolerance status

    DEFF Research Database (Denmark)

    Gjesing, Anette P; Vestmar, Marie A; Jørgensen, Torben

    2011-01-01

    Background: We aimed to evaluate the effects of the G-allele of rs6232 and the C-allele of rs6235 within PCSK1 on measures of body fat and glucose homeostasis in Danish individuals and to assess interactions of genotypes with age, sex and glucose tolerance status. Data were included in meta.......008) and increased waist-to-hip ratio of 0.004 (0.0005–0.008, p = 0.027). In the meta-analyses where men and women were combined, the rs6232 G-allele associated with increased waist-to-hip ratio (p = 0.02) and the rs6235 C-allele associated with increased waist circumference (p = 0.01). Furthermore, the rs6235 C......-allele was associated nominally with a 0.6% (0.1–1%, p = 0.01) reduction in fasting glucose, it interacted with glucose tolerance status for traits related to glucose metabolism and analysis among individuals having abnormal glucose tolerance revealed a 5% (20.7–9%, p = 0.02) elevated level of acute insulin response...

  2. Patterns of neuroendocrine coupling in 9-year-old children: Effects of sex, body-mass index, and life stress.

    Science.gov (United States)

    Black, Sarah R; Lerner, Matthew D; Shirtcliff, Elizabeth A; Klein, Daniel N

    2018-02-01

    Previous investigations have explored stress and pubertal hormones in parallel; it has been a recent development, however, to explore the relationships between different hormones during puberty, and how this hormonal cross-talk may be influenced by the environment. The current study investigated neuroendocrine coupling, or the extent to which hormones are correlated within the individual, and also investigated early life stressors that may influence coupling. Participants were 405 adrenarcheal children (mean Tanner stage=1.73 for girls and 1.38 for boys) from a longitudinal study who provided saliva samples for analysis of cortisol, dehydroepiandrosterone (DHEA), and testosterone. Saliva was collected when children were 9-years-old, while early life stressors were assessed at each longitudinal assessment (ages 3, 6, and 9). Results from multi-level modeling (MLM) analyses provided evidence of positive cortisol-dehydroepiandrosterone (DHEA) and cortisol-testosterone coupling in middle childhood, and identified body mass index as a predictor of the strength of hormone coordination. While exposure to stressful life events did not impact cortisol-DHEA coupling patterns, stress interacted with sex to predict looser cortisol-testosterone coupling in girls, but not boys. The current study adds to the existing literature on the development of neuroendocrine coupling, and provided further evidence of sex differences in the impact of stress. Furthermore, hormone coupling may be investigated in the future as a mechanism by which puberty is associated with negative behavioral outcomes. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Sex- and brain region-specific patterns of gene expression associated with socially-mediated puberty in a eusocial mammal.

    Directory of Open Access Journals (Sweden)

    Mariela Faykoo-Martinez

    Full Text Available The social environment can alter pubertal timing through neuroendocrine mechanisms that are not fully understood; it is thought that stress hormones (e.g., glucocorticoids or corticotropin-releasing hormone influence the hypothalamic-pituitary-gonadal axis to inhibit puberty. Here, we use the eusocial naked mole-rat, a unique species in which social interactions in a colony (i.e. dominance of a breeding female suppress puberty in subordinate animals. Removing subordinate naked mole-rats from this social context initiates puberty, allowing for experimental control of pubertal timing. The present study quantified gene expression for reproduction- and stress-relevant genes acting upstream of gonadotropin-releasing hormone in brain regions with reproductive and social functions in pre-pubertal, post-pubertal, and opposite sex-paired animals (which are in various stages of pubertal transition. Results indicate sex differences in patterns of neural gene expression. Known functions of genes in brain suggest stress as a key contributing factor in regulating male pubertal delay. Network analysis implicates neurokinin B (Tac3 in the arcuate nucleus of the hypothalamus as a key node in this pathway. Results also suggest an unappreciated role for the nucleus accumbens in regulating puberty.

  4. Mental health help seeking patterns and associations among Australian same sex attracted women, trans and gender diverse people: a survey-based study

    OpenAIRE

    McNair, Ruth P.; Bush, Rachel

    2016-01-01

    Background Same sex attracted women (SSAW) are disproportionately affected by depression and anxiety, due to experiences of sexuality and gender based discrimination. They access mental health services at higher rates than heterosexual women, however with lower levels of satisfaction. This study examined the range of professional and social help seeking by same-sex attracted women, and patterns according to sexual orientation and gender identity subgroup. Methods Eight key stakeholders were i...

  5. Induction of Metamorphosis Causes Differences in Sex-Specific Allocation Patterns in Axolotls (Ambystoma mexicanum) that Have Different Growth Histories.

    Science.gov (United States)

    Clarkson, Pamela M; Beachy, Christopher K

    2015-12-01

    We tested the hypothesis that salamanders growing at different rates would have allocation patterns that differ among male and female metamorphic and larval salamanders. We raised individual axolotls, Ambystoma mexicanum , on four food regimes: constant high growth (throughout the experiment), constant low growth (restricted throughout the experiment), high growth switched to low growth (ad libitum switched after 140 d to restricted), and low growth switched to high growth (restricted switched after 140 d to ad libitum). Because axolotls are obligate paedomorphs, we exposed half of the salamanders to thyroid hormone to induce metamorphosis. We assayed growth and dissected and weighed gonads and fat bodies. Salamanders that were switched from restricted to ad libitum food regime delayed metamorphosis. In all treatment groups, females had larger gonads than males and males had larger fat bodies than females. The association between storage and reproduction differed between larvae and metamorphs and depended on sex.

  6. Patterns of Social Affiliations and Healthcare Engagement Among Young, Black, Men Who Have Sex With Men.

    Science.gov (United States)

    Behler, Rachel L; Cornwell, Benjamin T; Schneider, John A

    2018-03-01

    Little work has examined how individuals' social affiliations-the venues in which they meet friends and engage in informal social interaction-influence their engagement with public health services. We investigate how links to these local places shape access to information and exposure to health-seeking behavior. Using longitudinal data from a respondent-driven sample of 618 young black men who have sex with men (YBMSM) in Chicago, we identify different sets of social venues that connect YBMSM. We then examine how YBMSM's connections within this network influence their receipt of HIV prevention and treatment services and knowledge of pre-exposure prophylaxis (PrEP). Our results show that YBMSM's positions within Chicago's venue network shape the types of health-related services they access, net of demographic, structural, and community covariates. Men with affiliations that are linked to the city's gay enclave are most likely to know about PrEP, while men with affiliations that are predominately in the black community demonstrate improved HIV treatment outcomes. Outreach engaging MSM beyond venues in gay enclaves is needed.

  7. Sex-specific patterns in cortical and trabecular bone microstructure in the Kirsten Skeletal Collection, South Africa.

    Science.gov (United States)

    Beresheim, Amy C; Pfeiffer, Susan K; Grynpas, Marc D; Alblas, Amanda

    2018-02-07

    The purpose of this study was to provide bone histomorphometric reference data for South Africans of the Western Cape who likely dealt with health issues under the apartheid regime. The 206 adult individuals ( n female = 75, n male = 131, mean = 47.9 ± 15.8 years) from the Kirsten Skeletal Collection, U. Stellenbosch, lived in the Cape Town metropole from the late 1960s to the mid-1990s. To study age-related changes in cortical and trabecular bone microstructure, photomontages of mid-thoracic rib cross-sections were quantitatively examined. Variables include relative cortical area (Rt.Ct.Ar), osteon population density (OPD), osteon area (On.Ar), bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp). All cortical variables demonstrated significant relationships with age in both sexes, with women showing stronger overall age associations. Peak bone mass was compromised in some men, possibly reflecting poor nutritional quality and/or substance abuse issues throughout adolescence and early adulthood. In women, greater predicted decrements in On.Ar and Rt.Ct.Ar suggest a structural disadvantage with age, consistent with postmenopausal bone loss. Age-related patterns in trabecular bone microarchitecture are variable and difficult to explain. Except for Tb.Th, there are no statistically significant relationships with age in women. Men demonstrate significant negative correlations between BV/TV, Tb.N, and age, and a significant positive correlation between Tb.Sp and age. This research highlights sex-specific differences in patterns of age-related bone loss, and provides context for discussion of contemporary South African bone health. While the study sample demonstrates indicators of poor bone quality, osteoporosis research continues to be under-prioritized in South Africa. © 2018 Wiley Periodicals, Inc.

  8. Circulating and intraprostatic sex steroid hormonal profiles in relation to male pattern baldness and chest hair density among men diagnosed with localized prostate cancers.

    Science.gov (United States)

    Zhou, Cindy Ke; Stanczyk, Frank Z; Hafi, Muhannad; Veneroso, Carmela C; Lynch, Barlow; Falk, Roni T; Niwa, Shelley; Emanuel, Eric; Gao, Yu-Tang; Hemstreet, George P; Zolfghari, Ladan; Carroll, Peter R; Manyak, Michael J; Sesterhenn, Isabell A; Levine, Paul H; Hsing, Ann W; Cook, Michael B

    2017-12-01

    Prospective cohort studies of circulating sex steroid hormones and prostate cancer risk have not provided a consistent association, despite evidence from animal and clinical studies. However, studies using male pattern baldness as a proxy of early-life or cumulative androgen exposure have reported significant associations with aggressive and fatal prostate cancer risk. Given that androgens underlie the development of patterned hair loss and chest hair, we assessed whether these two dermatological characteristics were associated with circulating and intraprostatic concentrations of sex steroid hormones among men diagnosed with localized prostate cancer. We included 248 prostate cancer patients from the NCI Prostate Tissue Study, who answered surveys and provided a pre-treatment blood sample as well as fresh frozen adjacent normal prostate tissue. Male pattern baldness and chest hair density were assessed by trained nurses before surgery. General linear models estimated geometric means and 95% confidence intervals (95%CIs) of each hormone variable by dermatological phenotype with adjustment for potential confounding variables. Subgroup analyses were performed by Gleason score (balding status with serum testosterone, dihydrotestosterone (DHT), estradiol, and sex hormone-binding globulin (SHBG), and a weak association with elevated intraprostatic testosterone. Conversely, neither circulating nor intraprostatic sex hormones were statistically significantly associated with chest hair density. Age-adjusted correlation between binary balding status and three-level chest hair density was weak (r = 0.05). There was little evidence to suggest that Gleason score or race modified these associations. This study provides evidence that balding status assessed at a mean age of 60 years may serve as a clinical marker for circulating sex hormone concentrations. The weak-to-null associations between balding status and intraprostatic sex hormones reaffirm differences in organ

  9. Correlation of maternal age, gravida status, major malformations, stillbirth and sex ratio in high level natural radiation areas of Kerala coast

    International Nuclear Information System (INIS)

    Sudheer, K.R.; Koya, P.K.M.; Jaikrishan, G.; Das, Birajalaxmi

    2016-01-01

    As a part of the ongoing study on biological and health effects of chronic low dose and/or dose rate on human population, consecutive births were monitored in selected Govt. hospitals located in normal and high level natural radiation areas (HLNRA) of Kerala coast. This area is unique because of its vast population size and varied range of background radiation level due to natural deposit of monazite containing thorium. The objective is to elucidate the role of chronic low dose radiation, if any, on the adverse pregnancy outcome. Since 1995, ∼1,70,000 newborns were monitored in this area, of which 74,238 singleton first births were monitored. Of these, 634 (0.85%) cases were observed with detectable major congenital malformations (that include serious structural, functional or cosmetic disability requiring surgical or medical management) and 240 (0.32%) cases were stillborn. Sex ratio at first birth was observed in the ratio of 1050 males to 1000 females. The distribution of age at marriage of the mothers was stratified into the following groups: d"18 years (15.5%), 19 20 years (25.9%), 21 22 years (25.6%), 23 24 years (17.2%) and >25 years (15.8%). It was observed that about 78.9% mothers had their first birth within one year of marriage, 13.7% had their first birth within 1.1 2 years and 5.2% within 2.1 4 years. About 2.2% (1613) mothers had their first child after 4 years or more. Individual, combined and interactive effects of age at marriage, first birth interval (first gravida status), background radiation levels and gender of the newborn on major congenital malformation and stillbirth will be discussed. (author)

  10. Effects of salinity on egg and fecal pellet production, development and survival, adult sex ratio and total life span in the calanoid copepod, Acartia tonsa: a laboratory study

    Science.gov (United States)

    Shayegan, Majid; Esmaeili Fereidouni, Abolghasem; Agh, Naser; Jani Khalili, Khosrow

    2016-07-01

    The effects of salinity on the copepod, Acartia tonsa in terms of daily egg production rate (EPR), hatching success, fecal pellet production rate (FPR), naupliar development time and survival, sex ratio, and total life span were determined in laboratory conditions through three experiments. In experiment 1, EPR, hatching success, and FPR of individual females were monitored at salinities of 13, 20, 35 and 45 during short-periods (seven consecutive days). Results show EPR was affected by salinity with the highest outputs recorded at 20 and 35, respectively, which were considerably higher than those at 13 and 45. Mean FPR was also higher in 35 and 20. In experiment 2, the same parameters were evaluated over total life span of females (long-term study). The best EPR and FPR were observed in 35, which was statistically higher than at 13 and 20. In experiment 3, survival rates of early nauplii until adult stage were lowest at a salinity of 13. The development time increased with increasing of salinity. Female percentage clearly decreased with increasing salinity. Higher female percentages (56.7% and 52.2%, respectively) were significantly observed at two salinities of 13 and 20 compared to that at 35 (25%). Total longevity of females was not affected by salinity increment. Based on our results, for mass culture we recommend that a salinity of 35 be adopted due to higher reproductive performances, better feeding, and faster development of A. tonsa.

  11. Inherited Sterility Induced in Progeny of Gamma Irradiated Males Spiny Bollworm, Earias insulana Boisd. II. Effect on Larval and Pupal Mortality, Development and Sex Ratio

    International Nuclear Information System (INIS)

    Amin, A.R.H.; Sallam, H.A.; Mohamed, H.F.

    2010-01-01

    Spiny bollworm, Earias insulana Boisd. adult males were irradiated with sub sterilizing doses of 50,80,100 and 150 Gray (Gy) of gamma radiation. The number of surviving larvae was dose dependant and larval/pupal mortality increased as the dose applied to P1 males was increased. The larval mortality among F3 was reduced compared with that of the F1 and F2. The average developmental time from egg hatch to adult emergence at the four tested doses was slightly affected among the progeny descendant of irradiated P1 males through the three successive generations. The percentage of adult emergence was evidently reduced among F1 and F2 progeny resulting from parental males exposed to the three higher irradiation doses (80,100 and 150 Gy).The sex ratio was slightly altered in favor of males among the majority of all treatments. Raman studies of irradiated and unirradiated stones at different temperatures and irradiation times showed a relation between the bands of scattered peaks corresponding to (OH) stretching modes of vibration with the color changes

  12. Can Sex Differences in Science Be Tied to the Long Reach of Prenatal Hormones? Brain Organization Theory, Digit Ratio (2D/4D), and Sex Differences in Preferences and Cognition.

    Science.gov (United States)

    Valla, Jeffrey; Ceci, Stephen J

    2011-03-01

    Brain organization theory posits a cascade of physiological and behavioral changes initiated and shaped by prenatal hormones. Recently, this theory has been associated with outcomes including gendered toy preference, 2D/4D digit ratio, personality characteristics, sexual orientation, and cognitive profile (spatial, verbal, and mathematical abilities). We examine the evidence for this claim, focusing on 2D/4D and its putative role as a biomarker for organizational features that influence cognitive abilities/interests predisposing males toward mathematically and spatially intensive careers. Although massive support exists for early brain organization theory overall, there are myriad inconsistencies, alternative explanations, and outright contradictions that must be addressed while still taking the entire theory into account. Like a fractal within the larger theory, the 2D/4D hypothesis mirrors this overall support on a smaller scale while likewise suffering from inconsistencies (positive, negative, and sex-dependent correlations), alternative explanations (2D/4D related to spatial preferences rather than abilities per se), and contradictions (feminine 2D/4D in men associated with higher spatial ability). Using the debate over brain organization theory as the theoretical stage, we focus on 2D/4D evidence as an increasingly important player on this stage, a demonstrative case in point of the evidential complexities of the broader debate, and an increasingly important topic in its own right.

  13. Sex chromosome repeats tip the balance towards speciation.

    Science.gov (United States)

    O'Neill, Michael J; O'Neill, Rachel J

    2018-04-06

    Because sex chromosomes, by definition, carry genes that determine sex, mutations that alter their structural and functional stability can have immediate consequences for the individual by reducing fertility, but also for a species by altering the sex ratio. Moreover, the sex-specific segregation patterns of heteromorphic sex chromosomes make them havens for selfish genetic elements that not only create sub-optimal sex ratios, but can also foster sexual antagonism. Compensatory mutations to mitigate antagonism or return sex ratios to a Fisherian optimum can create hybrid incompatibility and establish reproductive barriers leading to species divergence. The destabilizing influence of these selfish elements is often manifest within populations as copy number variants (CNVs) in satellite repeats and transposable elements (TE) or as CNVs involving sex determining genes, or genes essential to fertility and sex chromosome dosage compensation. This review catalogs several examples of well-studied sex chromosome CNVs in Drosophilids and mammals that underlie instances of meiotic drive, hybrid incompatibility and disruptions to sex differentiation and sex chromosome dosage compensation. While it is difficult to pinpoint a direct cause/effect relationship between these sex chromosome CNVs and speciation, it is easy to see how their effects in creating imbalances between the sexes, and the compensatory mutations to restore balance, can lead to lineage splitting and species formation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  14. Patterns of repeated anal cytology results among HIV-positive and HIV-negative men who have sex with men

    Directory of Open Access Journals (Sweden)

    Hilary A. Robbins

    2018-06-01

    Full Text Available Background: Men who have sex with men (MSM are at increased risk for anal cancer. In cervical cancer screening, patterns of repeated cytology results are used to identify low- and high-risk women, but little is known about these patterns for anal cytology among MSM. Methods: We analyzed Multicenter AIDS Cohort Study (MACS data for MSM who were offered anal cytology testing annually (HIV-positive or every 2 years (HIV-negative for 4 years. Results: Following an initial negative (normal cytology, the frequency of a second negative cytology was lower among HIV-positive MSM with CD4 ≥ 500 (74% or CD4 < 500 (68% than HIV-negative MSM (83% (p < 0.001. After an initial abnormal cytology, the frequency of a second abnormal cytology was highest among HIV-positive MSM with CD4 < 500 (70% compared to CD4 ≥ 500 (53% or HIV-negative MSM (46% (p = 0.003. Among HIV-positive MSM with at least three results, 37% had 3 consecutive negative results; 3 consecutive abnormal results were more frequent among CD4 < 500 (22% than CD4 ≥ 500 (10% (p = 0.008. Conclusions: More than one-third of HIV-positive MSM have consistently negative anal cytology over three years. Following abnormal anal cytology, a repeated cytology is commonly negative in HIV-negative or immunocompetent HIV-positive men, while persistent cytological abnormality is more likely among HIV-positive men with CD4 < 500. Keywords: Anal cancer, Anal cytology, HIV, MSM, Anal cancer screening

  15. How Good Is Your Rule of Thumb? Validating Male-to-Female Case Ratio as a Proxy for Men Who Have Sex With Men Involvement in N. gonorrhoeae Incidence at the County Level.

    Science.gov (United States)

    Stenger, Mark; Bauer, Heidi; Klingler, Ellen; Bell, Teal; Donnelly, Jennifer; Eaglin, Margaret; Jespersen, Megan; Madera, Robbie; Mattson, Melanie; Torrone, Elizabeth

    2018-03-01

    Lacking information on men who have sex with men (MSM) for most reported cases, sexually transmitted disease (STD) programs in the United States have used crude measures such as male-to-female case ratios (MFCR) as a rule of thumb to gauge MSM involvement at the local level, primarily with respect to syphilis cases in the past. Suitability of this measure for gonorrhea incidence has not previously been investigated. A random sample of gonorrhea cases reported from January 2010 through June 2013 were interviewed in selected counties participating in the STD Surveillance Network to obtain gender of sex partners and history of transactional sex. Weighted estimates of proportion of cases among MSM and proportion reporting transactional sex were developed; correlation between MFCR and proportion MSM was assessed. Male-to-female case ratio ranged from 0.66 to 8.7, and the proportion of cases occurring among MSM varied from 2.5% to 62.3%. The MFCR was strongly correlated with proportion of cases among MSM after controlling for transactional sex (Pearson partial r = 0.754, P < 0.0001). Male-to-female case ratio for gonorrhea at the county level is a reliable proxy measure indicating MSM involvement in gonorrhea case incidence and should be used by STD programs to tailor their programmatic mix to include MSM-specific interventions.

  16. Tissue specificity of the hormonal response in sex accessory tissues is associated with nuclear matrix protein patterns.

    Science.gov (United States)

    Getzenberg, R H; Coffey, D S

    1990-09-01

    The DNA of interphase nuclei have very specific three-dimensional organizations that are different in different cell types, and it is possible that this varying DNA organization is responsible for the tissue specificity of gene expression. The nuclear matrix organizes the three-dimensional structure of the DNA and is believed to be involved in the control of gene expression. This study compares the nuclear structural proteins between two sex accessory tissues in the same animal responding to the same androgen stimulation by the differential expression of major tissue-specific secretory proteins. We demonstrate here that the nuclear matrix is tissue specific in the rat ventral prostate and seminal vesicle, and undergoes characteristic alterations in its protein composition upon androgen withdrawal. Three types of nuclear matrix proteins were observed: 1) nuclear matrix proteins that are different and tissue specific in the rat ventral prostate and seminal vesicle, 2) a set of nuclear matrix proteins that either appear or disappear upon androgen withdrawal, and 3) a set of proteins that are common to both the ventral prostate and seminal vesicle and do not change with the hormonal state of the animal. Since the nuclear matrix is known to bind androgen receptors in a tissue- and steroid-specific manner, we propose that the tissue specificity of the nuclear matrix arranges the DNA in a unique conformation, which may be involved in the specific interaction of transcription factors with DNA sequences, resulting in tissue-specific patterns of secretory protein expression.

  17. Polytene chromosomes of monogenic and amphogenic Chrysomya species (Calliphoridae, Diptera): analysis of banding patterns and in situ hybridization with Drosophila sex determining gene sequences.

    Science.gov (United States)

    Puchalla, S

    1994-03-01

    Standard maps for the five banded polytene chromosomes found in trichogen cell nuclei of the monogenic blowfly Chrysomya rufifacies and the amphogenic Chrysomya pinguis are presented. The chromosomes are highly homologous in the two species; differences in banding patterns are predominantly caused by one pericentric and ten paracentric inversions. In chromosome 5 of the amphogenic Chrysomya phaonis, also analysed in this paper, an additional paracentric inversion was observed. The distribution of species specific inversions indicates that the monogenic C. rufifacies is phylogenetically older than the amphogenic species. The maternal sex realizer locus F'/f on polytene chromosome 5 of C. rufifacies is not associated with a structural heterozygosity. Chromosome pair 6 of C. rufifacies and the sex chromosome pair of C. pinguis are under-replicated in polytene nuclei; they consist of irregular chromatin granules, frequently associated with nucleolus material. Evolution of heteromorphic sex chromosomes in Chrysomya is probably correlated with heterochromatin accumulation. A search for sex determining genes in Chrysomya was initiated using sex determining sequences from Drosophila melanogaster for in situ hybridization. The polytene band 41A1 on chromosome 5 of monogenic and amphogenic Chrysomya species contains sequences homologous to the maternal sex determining gene daughterless (da). Homology to the zygotic gene Sex-lethal (Sxl) of Drosophila is detected in band 39A1 on chromosome 5 of C. rufifacies. The findings reported here are the first evidence for a possible homology between the da gene of Drosophila and the maternal sex realizer F' of C. rufifacies. An hypothesis for the evolution of the maternal effect sex determination of C. rufifacies is proposed.

  18. Patterns of Gender-Based Violence and Associations with Mental Health and HIV Risk Behavior Among Female Sex Workers in Mombasa, Kenya: A Latent Class Analysis.

    Science.gov (United States)

    Roberts, Sarah T; Flaherty, Brian P; Deya, Ruth; Masese, Linnet; Ngina, Jacqueline; McClelland, R Scott; Simoni, Jane; Graham, Susan M

    2018-03-30

    Gender-based violence (GBV) is common among female sex workers (FSWs) and is associated with multiple HIV risk factors, including poor mental health, high-risk sexual behavior, and sexually transmitted infections (STIs). Prior studies have focused on GBV of one type (e.g. physical or sexual) or from one kind of perpetrator (e.g., clients or regular partners), but many FSWs experience overlapping types of violence from multiple perpetrators, with varying frequency and severity. We examined the association between lifetime patterns of GBV and HIV risk factors in 283 FSWs in Mombasa, Kenya. Patterns of GBV were identified with latent class analysis based on physical, sexual, or emotional violence from multiple perpetrators. Cross-sectional outcomes included depressive symptoms, post-traumatic stress disorder (PTSD) symptoms, disordered alcohol and other drug use, number of sex partners, self-reported unprotected sex, prostate-specific antigen (PSA) in vaginal secretions, and a combined unprotected sex indicator based on self-report or PSA detection. We also measured HIV/STI incidence over 12 months following GBV assessment. Associations between GBV patterns and each outcome were modeled separately using linear regression for mental health outcomes and Poisson regression for sexual risk outcomes. Lifetime prevalence of GBV was 87%. We identified 4 GBV patterns, labeled Low (21% prevalence), Sexual (23%), Physical/Moderate Emotional (18%), and Severe (39%). Compared to women with Low GBV, those with Severe GBV had higher scores for depressive symptoms, PTSD symptoms, and disordered alcohol use, and had more sex partners. Women with Sexual GBV had higher scores for disordered alcohol use than women with Low GBV, but similar sexual risk behavior. Women with Physical/Moderate Emotional GBV had more sex partners and a higher prevalence of unprotected sex than women with Low GBV, but no differences in mental health. HIV/STI incidence did not differ significantly by GBV

  19. The discriminative ability of waist circumference, body mass index and waist-to-hip ratio in identifying metabolic syndrome: Variations by age, sex and race.

    Science.gov (United States)

    Cheong, Kee C; Ghazali, Sumarni M; Hock, Lim K; Subenthiran, Soobitha; Huey, Teh C; Kuay, Lim K; Mustapha, Feisul I; Yusoff, Ahmad F; Mustafa, Amal N

    2015-01-01

    Many studies have suggested that there is variation in the capabilities of BMI, WC and WHR in predicting cardiometabolic risk and that it might be confounded by gender, ethnicity and age group. The objective of this study is to examine the discriminative abilities of body mass index (BMI), waist circumference (WC) and waist-hip ratio (WHR) to predict two or more non-adipose components of the metabolic syndrome (high blood pressure, hypertriglyceridemia, low high density lipoprotein-cholesterol and high fasting plasma glucose) among the adult Malaysian population by gender, age group and ethnicity. Data from 2572 respondents (1044 men and 1528 women) aged 25-64 years who participated in the Non Communicable Disease Surveillance 2005/2006, a population-based cross sectional study, were analysed. Participants' socio-demographic details, anthropometric indices (BMI, WC and WHR), blood pressure, fasting lipid profile and fasting glucose level were assessed. Receiver operating characteristics curves analysis was used to evaluate the ability of each anthropometric index to discriminate MetS cases from non-MetS cases based on the area under the curve. Overall, WC had better discriminative ability than WHR for women but did not perform significantly better than BMI in both sexes, whereas BMI was better than WHR in women only. Waist circumference was a better discriminator of MetS compared to WHR in Malay men and women. Waist circumference and BMI performed better than WHR in Chinese women, men aged 25-34 years and women aged 35-44 years. The discriminative ability of BMI and WC is better than WHR for predicting two or more non-adipose components of MetS. Therefore, either BMI or WC measurements are recommended in screening for metabolic syndrome in routine clinical practice in the effort to combat cardiovascular disease and type II diabetes mellitus. Copyright © 2015 Diabetes India. Published by Elsevier Ltd. All rights reserved.

  20. Impact of insecticides used to control Spodoptera frugiperda (J.E. Smith in corn on survival, sex ratio, and reproduction of Trichogramma pretiosum Riley offspring

    Directory of Open Access Journals (Sweden)

    Jander R Souza

    2013-06-01

    Full Text Available Corn (Zea mays L. is cultivated in large areas and considered one of the world's major cereal crops. There are several arthropod pests that can reduce its production such as the fall armyworm, Spodoptera frugiperda (J.E. Smith (Lep.: Noctuidae, which is considered to be the main pest for corn. Fall armyworm is primarily controlled by insecticides. The use of biological control agents to manage this pest is growing with an emphasis on the egg parasitoid Trichogramma pretiosum Riley (Hym.: Trichogrammatidae. Thus, the aim of this research was to evaluate the impact of the following insecticides (g ai L-1 beta-cypermethrin (0.03, chlorfenapyr (0.60, chlorpyrifos (0.96, spinosad (0.16, etofenprox (0.10, triflumuron (0.08, alfa-cypermethrin/teflubenzuron (0.0425/0.0425, and lambda-cyhalothrin/thiamethoxam (0.11/0.083 on survival, sex ratio, reproduction, and T. pretiosum offspring. Distilled water was used as a control. Commercial insecticide formulations were diluted in distilled water. Bioassays used Anagasta kuehniella eggs treated with insecticides which were afterwards exposed to parasitism. Bioassays were conducted under controlled conditions at 25 ± 2 °C, 70 ± 10% RH, and 12:12 h photoperiod. Alfa-cypermethrin/teflubenzuron, beta-cypermethrin, chlorpyrifos, chlorfenapyr, spinosad, etofenprox, and lambda-cyhalothrin/thiamethoxam reduced parasitism capacity of maternal generation females as well as the percentage of insect emergence from the F1 generation. Only triflumuron was selective for T. pretiosum and can be recommended along with this parasitoid in fall armyworm management programs in corn.

  1. Characterization of the factor VIII defect in 147 patients with sporadic hemophilia A: Family studies indicate a mutation type-dependent sex ratio of mutation frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Becker, J.; Schmidt, W.; Olek, K. [Univ. of Bonn (Germany)] [and others

    1996-04-01

    The clinical manifestation of hemophilia A is caused by a wide range of different mutations. In this study the factor VIII genes of 147 severe hemophilia A patients-all exclusively from sporadic families-were screened for mutations by use of the complete panel of modern DNA techniques. The pathogenous defect could be characterized in 126 patients (85.7%). Fifty-five patients (37.4%) showed a F8A-gene inversion, 47 (32.0%) a point mutation, 14 (9.5%) a small deletion, 8 (5.4%) a large deletion, and 2 (1.4%) a small insertion. Further, four (2.7%) mutations were localized but could not be sequenced yet. No mutation could be identified in 17 patients (11.6%). Sixteen (10.9%) of the P identified mutations occurred in the B domain. Four of these were located in an adenosine nucleotide stretch at codon 1192, indicating a mutation hotspot. Somatic mosaicisms were detected in 3 (3.9%) of 76 patients` mothers, comprising 3 of 16 de novo mutations in the patients` mothers. Investigation of family relatives allowed detection of a de novo mutation in 16 of 76 two-generation and 28 of 34 three-generation families. On the basis of these data, the male:female ratio of mutation frequencies (k) was estimated as k = 3.6. By use of the quotients of mutation origin in maternal grandfather to patient`s mother or to maternal grandmother, k was directly estimated as k = 15 and k = 7.5, respectively. Considering each mutation type separately, we revealed a mutation type-specific sex ratio of mutation frequencies. Point mutations showed a 5-to-10-fold-higher and inversions a >10-fold- higher mutation rate in male germ cells, whereas deletions showed a >5-fold-higher mutation rate in female germ cells. Consequently, and in accordance with the data of other diseases like Duchenne muscular dystrophy, our results indicate that at least for X-chromosomal disorders the male:female mutation rate of a disease is determined by its proportion of the different mutation types. 68 refs., 1 fig., 5 tabs.

  2. Temporal patterns of charcoal burning suicides among the working age population in Hong Kong SAR: the influence of economic activity status and sex

    Directory of Open Access Journals (Sweden)

    Law Chi-kin

    2012-07-01

    Full Text Available Abstract Background Charcoal burning in a sealed room has recently emerged as the second most common suicide means in Hong Kong, causing approximately 200 deaths each year. As charcoal burning suicide victims have a unique sociodemographic profile (i.e., predominantly economically active men, they may commit suicide at specific times. However, little is known about the temporal patterns of charcoal burning suicides. Methods Suicide data from 2001 to 2008 on victims of usual working age (20–59 were obtained from the registered death files of the Census and Statistics Department of Hong Kong. A total of 1649 cases of charcoal burning suicide were analyzed using a two-step procedure, which first examined the temporal asymmetries in the incidence of suicide, and second investigated whether these asymmetries were influenced by sex and/or economic activity status. Poisson regression analyses were employed to model the monthly and daily patterns of suicide by economic activity status and sex. Results Our findings revealed pronounced monthly and daily temporal variations in the pattern of charcoal burning suicides in Hong Kong. Consistent with previous findings on overall suicide deaths, there was an overall spring peak in April, and Monday was the common high risk day for all groups. Although sex determined the pattern of variation in charcoal burning suicides, the magnitude of the variation was influenced by the economic activity status of the victims. Conclusion The traditional classification of suicide methods as either violent or nonviolent tends to elide the temporal variations of specific methods. The interaction between sex and economic activity status observed in the present study indicates that sex should be taken into consideration when investigating the influence of economic activity status on temporal variations of suicide. This finding also suggests that suicide prevention efforts should be both time- and subgroup-specific.

  3. Temporal patterns of charcoal burning suicides among the working age population in Hong Kong SAR: the influence of economic activity status and sex.

    Science.gov (United States)

    Law, Chi-kin; Leung, Candi M C

    2012-07-06

    Charcoal burning in a sealed room has recently emerged as the second most common suicide means in Hong Kong, causing approximately 200 deaths each year. As charcoal burning suicide victims have a unique sociodemographic profile (i.e., predominantly economically active men), they may commit suicide at specific times. However, little is known about the temporal patterns of charcoal burning suicides. Suicide data from 2001 to 2008 on victims of usual working age (20-59) were obtained from the registered death files of the Census and Statistics Department of Hong Kong. A total of 1649 cases of charcoal burning suicide were analyzed using a two-step procedure, which first examined the temporal asymmetries in the incidence of suicide, and second investigated whether these asymmetries were influenced by sex and/or economic activity status. Poisson regression analyses were employed to model the monthly and daily patterns of suicide by economic activity status and sex. Our findings revealed pronounced monthly and daily temporal variations in the pattern of charcoal burning suicides in Hong Kong. Consistent with previous findings on overall suicide deaths, there was an overall spring peak in April, and Monday was the common high risk day for all groups. Although sex determined the pattern of variation in charcoal burning suicides, the magnitude of the variation was influenced by the economic activity status of the victims. The traditional classification of suicide methods as either violent or nonviolent tends to elide the temporal variations of specific methods. The interaction between sex and economic activity status observed in the present study indicates that sex should be taken into consideration when investigating the influence of economic activity status on temporal variations of suicide. This finding also suggests that suicide prevention efforts should be both time- and subgroup-specific.

  4. Temporal patterns of charcoal burning suicides among the working age population in Hong Kong SAR: the influence of economic activity status and sex

    Science.gov (United States)

    2012-01-01

    Background Charcoal burning in a sealed room has recently emerged as the second most common suicide means in Hong Kong, causing approximately 200 deaths each year. As charcoal burning suicide victims have a unique sociodemographic profile (i.e., predominantly economically active men), they may commit suicide at specific times. However, little is known about the temporal patterns of charcoal burning suicides. Methods Suicide data from 2001 to 2008 on victims of usual working age (20–59) were obtained from the registered death files of the Census and Statistics Department of Hong Kong. A total of 1649 cases of charcoal burning suicide were analyzed using a two-step procedure, which first examined the temporal asymmetries in the incidence of suicide, and second investigated whether these asymmetries were influenced by sex and/or economic activity status. Poisson regression analyses were employed to model the monthly and daily patterns of suicide by economic activity status and sex. Results Our findings revealed pronounced monthly and daily temporal variations in the pattern of charcoal burning suicides in Hong Kong. Consistent with previous findings on overall suicide deaths, there was an overall spring peak in April, and Monday was the common high risk day for all groups. Although sex determined the pattern of variation in charcoal burning suicides, the magnitude of the variation was influenced by the economic activity status of the victims. Conclusion The traditional classification of suicide methods as either violent or nonviolent tends to elide the temporal variations of specific methods. The interaction between sex and economic activity status observed in the present study indicates that sex should be taken into consideration when investigating the influence of economic activity status on temporal variations of suicide. This finding also suggests that suicide prevention efforts should be both time- and subgroup-specific. PMID:22770504

  5. Otolith elemental ratios of flathead mullet Mugil cephalus in Taiwanese waters reveal variable patterns of habitat use

    Science.gov (United States)

    Wang, C. H.

    2014-12-01

    The migratory history of the flathead mullet (Mugil cephalus) in the coastal waters of Taiwan was evaluated by examining the elemental composition in the otoliths of 74 fish collected from 3 habitats of varying salinity by using laser-ablation inductively coupled plasma mass spectrometry. The mean (±SD) Sr:Ca ratio for the otolith edge differed significantly among the 3 habitats of varying ambient salinity. The otolith mean Sr:Ca ratio for offshore fish was 6.7 ± 2.0 × 10-3 and 4.2 ± 1.5 × 10-3 in the estuary, which was significantly higher than that for freshwater fish (2.8 ± 1.1 × 10-3). By contrast, the mean Ba:Ca ratio for the otolith edge of offshore fish was 87.1 ± 113.0 × 10-6 and 52.1 ± 22.3 × 10-6 in the estuary, which was significantly lower than that for the fish in the freshwater habitat (144.5 ± 54.8 × 10-6). Thus, the Ba:Ca ratio can be used as an alternative to the Sr:Ca ratio for evaluating the migration of M. cephalus between freshwater and saline water. However, the Mn:Ca and Mg:Ca ratios were not significantly different among the 3 habitats. Accordingly, the Sr:Ca and Ba:Ca ratios for the otoliths can be used to reconstruct the salinity history of M. cephalus. The variation in Sr:Ca and Ba:Ca ratios among life history profiles also suggested seasonal migratory behavior in relation to salinity in M. cephalus. These results have implications for developing additional extensive studies to resolve the relative importance of marine estuarine and freshwater habitats for sustaining production of M. cephalus fisheries.

  6. A decadal time series of water vapor and D / H isotope ratios above Zugspitze: transport patterns to central Europe

    Science.gov (United States)

    Hausmann, Petra; Sussmann, Ralf; Trickl, Thomas; Schneider, Matthias

    2017-06-01

    We present vertical soundings (2005-2015) of tropospheric water vapor (H2O) and its D / H isotope ratio (δD) derived from ground-based solar Fourier transform infrared (FTIR) measurements at Zugspitze (47° N, 11° E, 2964 m a.s.l.). Beside water vapor profiles with optimized vertical resolution (degrees of freedom for signal, DOFS, = 2.8), {H2O, δD} pairs with consistent vertical resolution (DOFS = 1.6 for H2O and δD) applied in this study. The integrated water vapor (IWV) trend of 2.4 [-5.8, 10.6] % decade-1 is statistically insignificant (95 % confidence interval). Under this caveat, the IWV trend estimate is conditionally consistent with the 2005-2015 temperature increase at Zugspitze (1.3 [0.5, 2.1] K decade-1), assuming constant relative humidity. Seasonal variations in free-tropospheric H2O and δD exhibit amplitudes of 140 and 50 % of the respective overall means. The minima (maxima) in January (July) are in agreement with changing sea surface temperature of the Atlantic Ocean. Using extensive backward-trajectory analysis, distinct moisture pathways are identified depending on observed δD levels: low column-based δD values (δDcol 95th percentile: 46° N, 4.6 km). Backward-trajectory classification indicates that {H2O, δD} observations are influenced by three long-range-transport patterns towards Zugspitze assessed in previous studies: (i) intercontinental transport from North America (TUS; source region: 25-45° N, 70-110° W, 0-2 km altitude), (ii) intercontinental transport from northern Africa (TNA; source region: 15-30° N, 15° W-35° E, 0-2 km altitude), and (iii) stratospheric air intrusions (STIs; source region: > 20° N, above zonal mean tropopause). The FTIR data exhibit significantly differing signatures in free-tropospheric {H2O, δD} pairs (5 km a.s.l.) - given as the mean with uncertainty of ±2 standard error (SE) - for TUS (VMRH2O = 2.4 [2.3, 2.6] × 103 ppmv, δD = -315 [-326, -303] ‰), TNA (2.8 [2.6, 2.9] × 103 ppmv, -251 [-257

  7. Change in ranking order of prescribing patterns by age and sex standardization of the practice population--audit may be misleading

    DEFF Research Database (Denmark)

    Olesen, Frede; Vedsted, Peter; Nielsen, Jørgen Nørskov

    1996-01-01

    OBJECTIVE: To demonstrate whether standardization of practice populations by age and sex changes the internal prescription ranking order of a group of practices. DESIGN: Data on the prescribing of cardiovascular drugs in a group of practices were obtained from a county-based database. Information...... on the age, sex, and numbers of patients per practice was also obtained. The direct standardization method was used to adjust practice populations for age and sex. SETTING: The town of Randers, Aarhus County, Denmark. SUBJECTS: 35 practices, 41 GPs. MAIN OUTCOME MEASURES: Ranking of the 35 practices...... of the practices. Only four practices did not change ranking position, while four moved more than ten places. The slope between highest and lowest ranked practice did not diminish after standardization. CONCLUSION: Care should be taken when comparing peer prescribing patterns from crude utilization data, and we...

  8. A distinct seasonal pattern of the ratio of soil respiration to total ecosystem respiration in a spruce-dominated forest

    Science.gov (United States)

    E.A. Davidson; A.D. Richardson; K.E. Savage; D.Y. Hollinger

    2006-01-01

    Annual budgets and fitted temperature response curves for soil respiration and ecosystem respiration provide useful information for partitioning annual carbon budgets of ecosystems, but they may not adequately reveal seasonal variation in the ratios of these two fluxes. Soil respiration (Rs) typically contributes 30-80% of...

  9. Development of a versatile sample preparation method and its application for rare-earth pattern and Nd isotope ratio analysis in nuclear forensics

    International Nuclear Information System (INIS)

    Krajko, J.

    2015-01-01

    An improved sample preparation procedure for trace-levels of lanthanides in uranium-bearing samples was developed. The method involves a simple co-precipitation using Fe(III) carrier in ammonium carbonate medium to remove the uranium matrix. The procedure is an effective initial pre-concentration step for the subsequent extraction chromatographic separations. The applicability of the method was demonstrated by the measurement of REE pattern and 143 Nd/ 144 Nd isotope ratio in uranium ore concentrate samples. (author)

  10. Seasonal variations in 228Ra/226Ra ratio within coastal waters of the Sea of Japan: implications for water circulation patterns in coastal areas

    International Nuclear Information System (INIS)

    Inoue, M.; Tanaka, K.; Watanabe, S.; Kofuji, H.; Yamamoto, M.; Komura, K.

    2006-01-01

    In this study, low-background γ-spectrometry was used to determine the 228 Ra/ 226 Ra ratio of 131 coastal water samples from various environments around Honshu Island, Japan (mainly around Noto Peninsula) at 1-3 month intervals from April 2003 until September 2005. Spatial variation in 228 Ra/ 226 Ra ratios was also assessed by analyzing 34 coastal water samples from five areas within the Sea of Japan during May and June 2004. The 228 Ra/ 226 Ra ratio of coastal water from all sites around Noto Peninsula shows seasonal variation, with minimum values during summer ( 228 Ra/ 226 Ra = 0.7) and maximum values during autumn-winter ( 228 Ra/ 226 Ra = 1.7-2). This seasonal variation is similar to that recorded for coastal water between Tsushima Strait and Noto Peninsula. The measured lateral variation in 228 Ra/ 226 Ra ratios within coastal water between Tsushima Strait and Noto Peninsula is only minor (0.5-0.7; May-June 2004). Coastal waters from two other sites (Pacific shore and Tsugaru Strait, north Honshu) show no clear seasonal variation in 228 Ra/ 226 Ra ratio. These measured variations in 228 Ra/ 226 Ra ratio, especially the temporal variations, have important implications for seasonal changes in patterns of coastal water circulation within the Sea of Japan

  11. Sex-specific variation in signaling pathways and gene expression patterns in human leukocytes in response to endotoxin and exercise.

    Science.gov (United States)

    Abbasi, Asghar; de Paula Vieira, Rodolfo; Bischof, Felix; Walter, Michael; Movassaghi, Masoud; Berchtold, Nicole C; Niess, Andreas M; Cotman, Carl W; Northoff, Hinnak

    2016-11-10

    While exercise effects on the immune system have received increasing attention in recent years, it remains unclear to what extent gender and fluctuations in sex hormones during menstrual cycle influence immunological responses to exercise. We investigated mRNA changes induced through exhaustive exercise (half-marathon; pre-exercise and post-exercise [30 min, 3 h, 24 h] on whole blood cultures ± lipopolysaccharide [LPS] [1 h]) with a specific focus on sex differences (men vs women in luteal phase) as an extension of our previous study. Inflammation related signaling pathways, TLRs, cytosolic DNA sensing and RIG-I like receptors were differentially activated between sexes in LPS-stimulated cultures. Genes differentially regulated between sexes included TNIP-1, TNIP-3, IL-6, HIVEP1, CXCL3, CCR3, IL-8, and CD69, revealing a bias towards less anti-inflammatory gene regulation in women compared to men. In addition, several genes relevant to brain function (KMO, DDIT4, VEGFA, IGF1R, IGF2R, and FGD4) showed differential activation between sexes. Some of these genes (e.g., KMO in women, DDIT4 in both sexes) potentially constitute neuroprotective mechanisms. These data reveal that the exercise-induced change in gene expression might be gender and menstrual cycle phase dependent.

  12. The Heart´s rhythm 'n' blues: Sex differences in circadian variation patterns of vagal activity vary by depressive symptoms in predominantly healthy employees.

    Science.gov (United States)

    Jarczok, Marc N; Aguilar-Raab, Corina; Koenig, Julian; Kaess, Michael; Borniger, Jeremy C; Nelson, Randy J; Hall, Martica; Ditzen, Beate; Thayer, Julian F; Fischer, Joachim E

    2018-03-15

    Successful regulation of emotional states is positively associated to mental health, while difficulties in regulating emotions are negatively associated to overall mental health and in particular associated with anxiety or depression symptoms. A key structure associated to socio-emotional regulatory processes is the central autonomic network. Activity in this structure is associated to vagal activity can be indexed noninvasively and simply by measures of peripheral cardiac autonomic modulations such as heart rate variability. Vagal activity exhibits a circadian variation pattern, with a maximum during nighttime. Depression is known to affect chronobiology. Also, depressive symptoms are known to be associated with decreased resting state vagal activity, but studies investigating the association between circadian variation pattern of vagal activity and depressive symptoms are scarce. We aim to examine these patterns in association to symptom severity of depression using chronobiologic methods. Data from the Manheim Industrial Cohort Studies (MICS) were used. A total of 3,030 predominantly healthy working adults underwent, among others, ambulatory 24-h hear rate-recordings, detailed health examination and online questionnaires and were available for this analysis. The root mean sum of successive differences (RMSSD) was used as an indicator of vagally mediated heart rate variability. Three individual-level cosine function parameters (MESOR, amplitude, acrophase) were estimated to quantify circadian variation pattern. Multivariate linear regression models including important covariates such as age, sex, and lifestyle factors as well as an interaction effect of sex with depressive symptoms were used to estimate the association of circadian variation pattern of vagal activity with depressive symptoms simultaneously. The analysis sample consisted of 20.2% females and an average age 41 with standard deviation of 11 years. Nonparametric bivariate analysis revealed

  13. Repeated in utero and lactational 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure affects male gonads in offspring, leading to sex ratio changes in F2 progeny

    International Nuclear Information System (INIS)

    Ikeda, Masahiko; Tamura, Masashi; Yamashita, Junko; Suzuki, Chinatsu; Tomita, Takako

    2005-01-01

    The effects of in utero and lactational 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the reproductive system of male rat offspring (F 1 ) and the sex ratio of the subsequent generation (F 2 ) were examined. Female Holtzman rats were gavaged with an initial loading dose of 400 ng/kg TCDD prior to mating, followed by weekly maintenance doses of 80 ng/kg during mating, pregnancy, and the lactation period. Maternal exposure to TCDD had no significant effects on fetus/pup (F 1 ) mortality, litter size, or sex ratio on gestation day (GD) 20 or postnatal day (PND) 2. The TCDD concentration in maternal livers and adipose tissue on GD20 was 1.21 and 1.81 ng/kg, respectively, and decreased at weaning to 0.72 in the liver and 0.84 in the adipose tissue. In contrast, the TCDD concentration in pup livers was 1.32 ng/kg on PND2 and increased to 1.80 ng/kg at weaning. Ventral prostate weight of male offspring was significantly decreased by TCDD exposure on PND28 and 120 compared with that of controls. Weight of the testes, cauda epididymides, and seminal vesicle, and sperm number in the cauda epididymis were not changed by TCDD exposure at PND120. TCDD- or vehicle-exposed male offspring were mated with unexposed females. The sex ratio (percentage of male pups) of F 2 offspring was significantly reduced in the TCDD-exposed group compared with controls. These results suggest that in utero and lactational TCDD exposures affect the development of male gonads in offspring (F 1 ), leading to changes in the sex ratio of the subsequent generation (F 2 )

  14. Influence of different aspect ratios on the structural and electrical properties of GaN thin films grown on nanoscale-patterned sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Fang-Wei [Department of Electrophysics, National Chiao-Tung University, Hsinchu 300, Taiwan (China); Ke, Wen-Cheng, E-mail: wcke@mail.ntust.edu.tw [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Cheng, Chun-Hong; Liao, Bo-Wei; Chen, Wei-Kuo [Department of Electrophysics, National Chiao-Tung University, Hsinchu 300, Taiwan (China)

    2016-07-01

    Highlights: • Nanoscale patterned sapphire substrate was prepared by anodic-aluminum-oxide etching mask. • Influence of aspect ratio of NPSS on structural and electrical properties of GaN films was studied. • Low dislocation density and high carrier mobility of GaN films were grown on high aspect ratio NPSS. - Abstract: This study presents GaN thin films grown on nanoscale-patterned sapphire substrates (NPSSs) with different aspect ratios (ARs) using a homemade metal-organic chemical vapor deposition system. The anodic aluminum oxide (AAO) technique is used to prepare the dry etching mask. The cross-sectional view of the scanning electron microscope image shows that voids exist between the interface of the GaN thin film and the high-AR (i.e. ∼2) NPSS. In contrast, patterns on the low-AR (∼0.7) NPSS are filled full of GaN. The formation of voids on the high-AR NPSS is believed to be due to the enhancement of the lateral growth in the initial growth stage, and the quick-merging GaN thin film blocks the precursors from continuing to supply the bottom of the pattern. The atomic force microscopy images of GaN on bare sapphire show a layer-by-layer surface morphology, which becomes a step-flow surface morphology for GaN on a high-AR NPSS. The edge-type threading dislocation density can be reduced from 7.1 × 10{sup 8} cm{sup −2} for GaN on bare sapphire to 4.9 × 10{sup 8} cm{sup −2} for GaN on a high-AR NPSS. In addition, the carrier mobility increases from 85 cm{sup 2}/Vs for GaN on bare sapphire to 199 cm{sup 2}/Vs for GaN on a high-AR NPSS. However, the increased screw-type threading dislocation density for GaN on a low-AR NPSS is due to the competition of lateral growth on the flat-top patterns and vertical growth on the bottom of the patterns that causes the material quality of the GaN thin film to degenerate. Thus, the experimental results indicate that the AR of the particular patterning of a NPSS plays a crucial role in achieving GaN thin film with

  15. Dietary patterns among girls aged 16–18 years old according to their body mass index and waist-to-hip ratio

    Directory of Open Access Journals (Sweden)

    Agnieszka Dmitruk

    2018-03-01

    Full Text Available Aim: The study has been aimed at evaluating dietary patterns of girls aged 16–18 years old in groups identified according to measures such as their body mass index and waist-to-hip ratio. Material and methods: The study covered a total of 151 girls aged 16–18 years old from selected higher secondary schools in Biała Podlaska, Poland. Based on height, weight, waist and hip circumference measurements, body mass index was calculated for each of the participants of the study, allowing to identify two groups: group 1 with normal index and group 2 with overweight or obesity. Also, to determine the type of obesity in the overweight and obese respondents, their waist-to-hip ratio was calculated, identifying the subgroup of girls with abdominal obesity. The respondents’ dietary patterns were identified with the use of a diagnostic survey. The statistical significance of the differences between the participants with normal body mass index and the overweight and obese respondents (including those with abdominal obesity was tested with the chi-square test. Results: Numerous nutritional mistakes/unhealthy dietary patterns were identified in the studied group, largely involving the overweight and obese girls, including those with abdominal obesity. The respondents whose body mass index and waist-to-hip ratio were too high ate fewer meals per day, skipped breakfast more frequently, had their last meal of the day later than 8 p.m., reported less frequent fish and wholemeal bread intake, as opposed to more frequent fast food, sweets and sweetened beverages intake. Conclusion: The unhealthy dietary patterns found in the population of girls with high body mass index and abdominal obesity highlight the need for education in the scope of healthy nutrition aimed both at overweight/obese individuals and their families.

  16. Sex-specific patterns in abundance, temporary emigration and survival of Indo-Pacific bottlenose dolphins (Tursiops aduncus in coastal and estuarine waters

    Directory of Open Access Journals (Sweden)

    Kate R Sprogis

    2016-02-01

    Full Text Available Inherent difficulties in determining the sex of free-ranging sexually monomorphic species often prevents a sex-specific focus on estimating abundance, movement patterns and survival rates. This study provides insights into sex-specific population parameters of Indo-Pacific bottlenose dolphins (Tursiops aduncus. Systematic, boat-based photo-identification surveys (n = 417 were conducted year-round from 2007-2013 in coastal and estuarine waters off Bunbury, Western Australia. Pollock’s Robust Design was used to quantify population parameters for three datasets: i adults and juveniles combined, ii adult females and iii adult males. For all datasets, abundance estimates varied seasonally, with general highs during summer and/or autumn, and lows during winter. Dolphins had seasonally structured temporary emigration rates with similar trends between sexes. The derived return rate (1-γ’ of temporary emigrants into the study area was highest from winter to spring, indicating that dolphins had a high probability of return into the study area during spring. We suggest that the return of dolphins into the study area and increase in abundance is influenced by the breeding season (summer/autumn. Prey availability is likely a main driver responsible for the movement of dolphins out of the study area during winter. Seasonal apparent survival rates were constant and high (0.98-0.99 for all datasets. High apparent survival rates suggest there is no permanent emigration from the study area. Our sex-specific modeling approach offers a comprehensive interpretation of the population dynamics of a top predator in a coastal and estuarine environment and acts as a model for future sex-based population studies on sexually monomorphic species.

  17. Attentional Bias for Pain and Sex, and Automatic Appraisals of Sexual Penetration: Differential Patterns in Dyspareunia vs Vaginismus?

    Science.gov (United States)

    Melles, Reinhilde J; Dewitte, Marieke D; Ter Kuile, Moniek M; Peters, Madelon M L; de Jong, Peter J

    2016-08-01

    Current information processing models propose that heightened attention bias for sex-related threats (eg, pain) and lowered automatic incentive processes ("wanting") may play an important role in the impairment of sexual arousal and the development of sexual dysfunctions such as genitopelvic pain/penetration disorder (GPPPD). Differential threat and incentive processing may also help explain the stronger persistence of coital avoidance in women with vaginismus compared to women with dyspareunia. As the first aim, we tested if women with GPPPD show (1) heightened attention for pain and sex, and (2) heightened threat and lower incentive associations with sexual penetration. Second, we examined whether the stronger persistence of coital avoidance in vaginismus vs dyspareunia might be explained by a stronger attentional bias or more dysfunctional automatic threat/incentive associations. Women with lifelong vaginismus (n = 37), dyspareunia (n = 29), and a no-symptoms comparison group (n = 51) completed a visual search task to assess attentional bias, and single target implicit-association tests to measure automatic sex-threat and sex-wanting associations. There were no group differences in attentional bias or automatic associations. Correlational analysis showed that slowed detection of sex stimuli and stronger automatic threat associations were related to lowered sexual arousal. The findings do not corroborate the view that attentional bias for pain or sex contributes to coital pain, or that differences in coital avoidance may be explained by differences in attentional bias or automatic threat/incentive associations. However, the correlational findings are consistent with the view that automatic threat associations and impaired attention for sex stimuli may interfere with the generation of sexual arousal. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

  18. Patterns and risk factors of inconsistent condom use among men who have sex with men in Viet Nam: Results from an Internet-based cross-sectional survey.

    Science.gov (United States)

    García, Macarena C; Duong, Quyen L; Mercer, Licelot C Eralte; Meyer, Samantha B; Koppenhaver, Todd; Ward, Paul R

    2014-01-01

    Survey data from men who have sex with men (MSM) in Asian cities indicate drastic increases in HIV prevalence. It is unknown which factors are most important in driving these epidemics. The objective of this study was to identify patterns of condom use among MSM Internet users living in Viet Nam, as well as risk factors associated with inconsistent condom use and non-condom use. A national Internet-based survey of sexual behaviours was administered in 2011. Results showed that 44.9% of MSM reported not using a condom during their last anal sex encounter with a male partner. MSM were less likely to report condom use during anal sex with long-term partners than with casual partners. Twenty-three and a half per cent of MSM surveyed had ever taken an HIV test and received the results. Study findings highlight the urgent need for targeted strategies focused on increasing the rate of consistent condom use during anal sex with male partners among MSM in Viet Nam.

  19. Sexual patterns and protogynous sex reversal in the rusty parrotfish, Scarus ferrugineus (Scaridae): histological and physiological studies.

    Science.gov (United States)

    Abdel-Aziz, El-Sayedah H; Bawazeer, Fayzah A; El-Sayed Ali, Tamer; Al-Otaibi, Mashael

    2012-08-01

    Gonadal histology confirmed that Scarus ferrugineus is a diandric protogynous fish. The process of protogynous sex reversal was investigated through histological observations on the gonads of females changing sex to male. This process was divided into three stages on the basis of changes in the structure of the germinal and somatic elements. Ovaries of functional females (stages IV-V) were filled with vitellogenic oocytes during the breeding season but contained no trace of spermatogenic tissue. During post-spawning period, the remaining vitellogenic oocytes began to degenerate and accompanied by a drop in plasma levels of estradiol-17β. At the commencement of sex change, previtellogenic oocytes began to degenerate and stromal cell aggregation was observed in the central region of the lamellae. At mid-reversal stage, steroid-producing cells (Leydig cells) developed at the border of the stromal aggregate and spermatogonial cysts appear at the periphery of lamellae. Finally, sex change to secondary males was considered complete, with the beginning of active spermatogenesis and spermiation. Plasma levels of testosterone remained low throughout the sex change, but II-KT increased rapidly parallel to the increased number of Leydig cells while the level of estradiol-17β decreased. The results indicate also that the sex-changed males had higher level of II-KT than primary males, while primary males had higher level of testosterone. Histological examination revealed that testes of primary and secondary males are almost identical in organization of the spermatogenic cysts, association of sertoli cells, and developing germ cells but differ in clustering and development of Leydig cells.

  20. The ultimate intrinsic signal-to-noise ratio of loop- and dipole-like current patterns in a realistic human head model.

    Science.gov (United States)

    Pfrommer, Andreas; Henning, Anke

    2018-03-13

    The ultimate intrinsic signal-to-noise ratio (UISNR) represents an upper bound for the achievable SNR of any receive coil. To reach this threshold a complete basis set of equivalent surface currents is required. This study systematically investigated to what extent either loop- or dipole-like current patterns are able to reach the UISNR threshold in a realistic human head model between 1.5 T and 11.7 T. Based on this analysis, we derived guidelines for coil designers to choose the best array element at a given field strength. Moreover, we present ideal current patterns yielding the UISNR in a realistic body model. We distributed generic current patterns on a cylindrical and helmet-shaped surface around a realistic human head model. We excited electromagnetic fields in the human head by using eigenfunctions of the spherical and cylindrical Helmholtz operator. The electromagnetic field problem was solved by a fast volume integral equation solver. At 7 T and above, adding curl-free current patterns to divergence-free current patterns substantially increased the SNR in the human head (locally >20%). This was true for the helmet-shaped and the cylindrical surface. On the cylindrical surface, dipole-like current patterns had high SNR performance in central regions at ultra-high field strength. The UISNR increased superlinearly with B0 in most parts of the cerebrum but only sublinearly in the periphery of the human head. The combination of loop and dipole elements could enhance the SNR performance in the human head at ultra-high field strength. © 2018 International Society for Magnetic Resonance in Medicine.

  1. Low-temperature plasma etching of high aspect-ratio densely packed 15 to sub-10 nm silicon features derived from PS-PDMS block copolymer patterns

    International Nuclear Information System (INIS)

    Liu, Zuwei; Sassolini, Simone; Olynick, Deirdre L; Gu, Xiaodan; Hwu, Justin

    2014-01-01

    The combination of block copolymer (BCP) lithography and plasma etching offers a gateway to densely packed sub-10 nm features for advanced nanotechnology. Despite the advances in BCP lithography, plasma pattern transfer remains a major challenge. We use controlled and low substrate temperatures during plasma etching of a chromium hard mask and then the underlying substrate as a route to high aspect ratio sub-10 nm silicon features derived from BCP lithography. Siloxane masks were fabricated using poly(styrene-b-siloxane) (PS-PDMS) BCP to create either line-type masks or, with the addition of low molecular weight PS-OH homopolymer, dot-type masks. Temperature control was essential for preventing mask migration and controlling the etched feature’s shape. Vertical silicon wire features (15 nm with feature-to-feature spacing of 26 nm) were etched with aspect ratios up to 17 : 1; higher aspect ratios were limited by the collapse of nanoscale silicon structures. Sub-10 nm fin structures were etched with aspect ratios greater than 10 : 1. Transmission electron microscopy images of the wires reveal a crystalline silicon core with an amorphous surface layer, just slightly thicker than a native oxide. (paper)

  2. Seasonal variation of 228Ra/226Ra ratio in seaweed: implications for water circulation patterns in coastal areas of the Noto Peninsula, Japan

    International Nuclear Information System (INIS)

    Inoue, M.; Kofuji, H.; Yamamoto, M.; Komura, K.

    2005-01-01

    To examine water circulation patterns of coastal water, 72 seaweed (Sargasso) samples and 27 coastal water samples were collected from coastal areas of the Noto Peninsula, Japan, during the period from December 1998 to June 2002. The 228 Ra and 226 Ra activities of those samples were measured by low-background γ-ray spectrometry. There was a wide range of activities of 228 Ra (0.5-2 Bq/kg-fresh) and 226 Ra (0.5-1.2 Bq/kg-fresh) in the Sargasso samples. The 228 Ra/ 226 Ra activity ratio of Sargasso samples exhibited seasonal variation with minimum values in June ( 228 Ra/ 226 Ra = ∼1) and maximum values in December (1.5-2.5), which was mainly governed by changes in 228 Ra activity. It is also notable that the seasonal variation of the 228 Ra/ 226 Ra ratio of Sargasso is in approximate agreement with that of the ambient coastal water. Sargasso samples appear to have retained the 228 Ra/ 226 Ra ratio of the ambient coastal waters, and the temporal variations in that ratio provide insight into seasonal changes in water circulation in the Noto Peninsula coastal area

  3. Using a Classification of Occupations to Describe Age, Sex, and Time Differences in Employment Patterns. Report No. 223.

    Science.gov (United States)

    Gottfredson, Gary D.; Daiger, Denise C.

    Employment data from the 1960 and 1970 censuses were organized using the occupational classification system of John Holland to examine age, sex, and level differences in employment and to detect changes over the 10-year period. Data were organized by both kind and level of work in an attempt to answer the following questions: What are the relative…

  4. Attentional bias for pain and sex, and automatic appraisals of sexual penetration : Differential patterns in dyspareunia versus vaginismus?

    NARCIS (Netherlands)

    Melles, Reinhilde J.; Dewitte, Marieke D.; ter Kuile, Moniek M.; Peters, Madelon M.L.; Jong, de Peter J.

    Introduction Current information processing models propose that heightened attention bias for sex-related threats (eg, pain) and lowered automatic incentive processes (“wanting”) may play an important role in the impairment of sexual arousal and the development of sexual dysfunctions such as

  5. From swing to cane: Sex differences of EEG resting-state temporal patterns during maturation and aging

    Directory of Open Access Journals (Sweden)

    M.I. Tomescu

    2018-06-01

    Full Text Available While many insights on brain development and aging have been gained by studying resting-state networks with fMRI, relating these changes to cognitive functions is limited by the temporal resolution of fMRI. In order to better grasp short-lasting and dynamically changing mental activities, an increasing number of studies utilize EEG to define resting-state networks, thereby often using the concept of EEG microstates. These are brief (around 100 ms periods of stable scalp potential fields that are influenced by cognitive states and are sensitive to neuropsychiatric diseases. Despite the rising popularity of the EEG microstate approach, information about age changes is sparse and nothing is known about sex differences. Here we investigated age and sex related changes of the temporal dynamics of EEG microstates in 179 healthy individuals (6–87 years old, 90 females, 204-channel EEG. We show strong sex-specific changes in microstate dynamics during adolescence as well as at older age. In addition, males and females differ in the duration and occurrence of specific microstates. These results are of relevance for the comparison of studies in populations of different age and sex and for the understanding of the changes in neuropsychiatric diseases.

  6. Putative pathway of sex pheromone biosynthesis and degradation by expression patterns of genes identified from female pheromone gland and adult antenna of Sesamia inferens (Walker).

    Science.gov (United States)

    Zhang, Ya-Nan; Xia, Yi-Han; Zhu, Jia-Yao; Li, Sheng-Yun; Dong, Shuang-Lin

    2014-05-01

    The general pathway of biosynthesis and degradation for Type-I sex pheromones in moths is well established, but some genes involved in this pathway remain to be characterized. The purple stem borer, Sesamia inferens, employs a pheromone blend containing components with three different terminal functional groups (Z11-16:OAc, Z11-16:OH, and Z11-16:Ald) of Type-I sex pheromones. Thus, it provides a good model to study the diversity of genes involved in pheromone biosynthesis and degradation pathways. By analyzing previously obtained transcriptomic data of the sex pheromone glands and antennae, we identified 73 novel genes that are possibly related to pheromone biosynthesis (46 genes) or degradation (27 genes). Gene expression patterns and phylogenetic analysis revealed that one desaturase (SinfDes4), one fatty acid reductase (SinfFAR2), and one fatty acid xtransport protein (SinfFATP1) genes were predominantly expressed in pheromone glands, and clustered with genes involved in pheromone synthesis in other moth species. Ten genes including five carboxylesterases (SinfCXE10, 13, 14, 18, and 20), three aldehyde oxidases (SinfAOX1, 2 and 3), and two alcohol dehydrogenases (SinfAD1 and 3) were expressed specifically or predominantly in antennae, and could be candidate genes involved in pheromone degradation. SinfAD1 and 3 are the first reported alcohol dehydrogenase genes with antennae-biased expression. Based on these results we propose a pathway involving these potential enzyme-encoding gene candidates in sex pheromone biosynthesis and degradation in S. inferens. This study provides robust background information for further elucidation of the genetic basis of sex pheromone biosynthesis and degradation, and ultimately provides potential targets to disrupt sexual communication in S. inferens for control purposes.

  7. The influence of environment, sex, and innate timing mechanisms on body temperature patterns of free-ranging black-tailed prairie dogs (Cynomys ludovicianus).

    Science.gov (United States)

    Lehmer, Erin M; Bossenbroek, Jonathan M; Van Horne, Beatrice

    2003-01-01

    Mechanisms that influence body temperature patterns in black-tailed prairie dogs are not well understood. Previous research on both free-ranging and laboratory populations of black-tailed prairie dogs (Cynomys ludovicianus) has suggested that reductions in ambient temperature and food and water deprivation are the primary factors that stimulate torpor in this species. In other species, however, torpor has been shown to be influenced by a multitude of factors, including innate circadian and circannual timing mechanisms, energy status, and reproductive behaviors. Our objective was to clarify the influence of weather, sex, and intrinsic timing mechanisms on the body temperature patterns of free-ranging black-tailed prairie dogs. We monitored body temperatures of eight adult (>1 yr) prairie dogs from November 1999 to June 2000. Prairie dogs showed distinct daily and seasonal body temperature patterns, which reflected changes in ambient temperatures that occurred during these periods. These patterns of daily and seasonal heterothermy suggest that body temperature patterns of black-tailed prairie dogs may be driven by an innate timing mechanism. All prairie dogs entered torpor intermittently throughout winter and spring. Torpor bouts appeared to be influenced by precipitation and reductions in ambient temperature. Our results also suggest that reproductive behaviors and circadian timing may influence torpor in this species.

  8. Exploring Patterns of Awareness and Use of HIV Pre-Exposure Prophylaxis Among Young Men Who Have Sex with Men.

    Science.gov (United States)

    Strauss, Benjamin B; Greene, George J; Phillips, Gregory; Bhatia, Ramona; Madkins, Krystal; Parsons, Jeffrey T; Mustanski, Brian

    2017-05-01

    Pre-exposure prophylaxis (PrEP) has shown promise as a safe and effective HIV prevention strategy, but there is limited research on awareness and use among young men who have sex with men (YMSM). Using baseline data from the "Keep It Up! 2.0" randomized control trial, we examined differences in PrEP awareness and use among racially diverse YMSM (N = 759; mean age = 24.2 years). Participants were recruited from study sites in Atlanta, Chicago, and New York City, as well as through national advertising on social media applications. While 67.5 % of participants reported awareness of PrEP, 8.7 % indicated using the medication. Awareness, but not use, varied by demographic variables. PrEP-users had twice as many condomless anal sex partners (ERR = 2.05) and more condomless anal sex acts (ERR = 1.60) than non-users. Future research should aim to improve PrEP awareness and uptake among YMSM and address condom use.

  9. Safe sex

    Science.gov (United States)

    ... sex; Sexually transmitted - safe sex; GC - safe sex; Gonorrhea - safe sex; Herpes - safe sex; HIV - safe sex; ... contact. STIs include: Chlamydia Genital herpes Genital warts Gonorrhea Hepatitis HIV HPV Syphilis STIs are also called ...

  10. Socialization Patterns and Their Association with Unprotected Anal Intercourse, HIV, and Syphilis Among High-Risk Men Who Have Sex with Men and Transgender Women in Peru

    Science.gov (United States)

    Verre, MC; Peinado, J; Segura, ER; Clark, JC; Gonzales, P; Benites, C; Cabello, R; Sanchez, J; Lama, JR

    2014-01-01

    The association of socialization patterns with unprotected anal intercourse (UAI) and HIV/STI prevalence remains underexplored in men who have sex with men (MSM) and transgender women (TW) in developing country settings. We evaluated the correlation of UAI, HIV, and syphilis with MSM/TW venue attendance and social network size among high-risk MSM and TW in Peru according to self-reported sexual identity. Frequency of venue attendance and MSM/TW social network size were lowest among heterosexual MSM and highest among TW respondents. Attendance (frequent or occasional) at MSM/TW venues was associated with increased odds of insertive UAI among heterosexual participants. Frequent venue attendance was associated with increased odds of receptive UAI among gay/homosexual, bisexual, and TW participants. Further investigation of the differing socialization patterns and associations with HIV/STI transmission within subgroups of Peruvian MSM and TW will enable more effective prevention interventions for these populations. PMID:24788782

  11. Pod-1/Capsulin shows a sex- and stage-dependent expression pattern in the mouse gonad development and represses expression of Ad4BP/SF-1.

    Science.gov (United States)

    Tamura, M; Kanno, Y; Chuma, S; Saito, T; Nakatsuji, N

    2001-04-01

    Mammalian sex-determination and differentiation are controlled by several genes, such as Sry, Sox-9, Dax-1 and Mullerian inhibiting substance (MIS), but their upstream and downstream genes are largely unknown. Ad4BP/SF-1, encoding a zinc finger transcription factor, plays important roles in gonadogenesis. Disruption of this gene caused disappearance of the urogenital system including the gonad. Ad4BP/SF-1, however, is also involved in the sex differentiation of the gonad at later stages, such as the regulation of steroid hormones and MIS. Pod-1/Capsulin, a member of basic helix-loop-helix transcription factors, is expressed in a pattern closely related but mostly complimentary to that of the Ad4BP/SF-1 expression in the developing gonad. In the co-transfection experiment using cultured cells, overexpression of Pod-1/Capsulin repressed expression of a reporter gene that carried the upstream regulatory region of the Ad4BP/SF-1 gene. Furthermore, forced expression of Pod-1/Capsulin repressed expression of Ad4BP/SF-1 in the Leydig cell-derived I-10 cells. These results suggest that Pod-1/Capsulin may play important roles in the development and sex differentiation of the mammalian gonad via transcriptional regulation of Ad4BP/SF-1.

  12. Influences of Gender, Religion, Dietary Patterns, and Mixed-sex Education on Aggressiveness in Children: A Sociodemographic Study in Municipal Primary Schools of South Delhi.

    Science.gov (United States)

    Jain, Khushbu; Sharma, Schweta; Prajna, Samani Chaitanya; Jain, Viney

    2018-01-01

    Increasing antisocial and violent behaviors in adolescents and young adults present serious challenges for public health. Children with persistent high levels of aggressiveness are often associated with developing conduct disorders later in life. Early detection of highly aggressive children and sociodemographic risk-modifying factors are important for developing effective preventive strategies. The present study was undertaken to assess levels of aggressiveness for detecting highly aggressive children in sample populations of primary school children in an urban setting and determine significant biosociocultural risk-modifying factors in this scenario. The study was conducted during August-September, 2015 in 5 primary schools of South Delhi Municipal Corporation. Sociodemographic data on 2080 students were collected. Overall aggressiveness scores (OA-Scores) were estimated using a self-report questionnaire in Hindi. Categorizing students according to their OA-Scores, the data revealed that highly aggressive children constituted 4.3% of the study population. Analysis showed significant influence of (a) gender: boys displayed higher levels of aggressiveness compared to girls; (b) dietary pattern: omnivores showed higher aggressiveness than vegetarians; and (c) school environment: boys in mixed-sex (coeducational) schools displayed lower aggressiveness than from single-sex schools. Statistically significant influences of religion (Hindu/Muslim) and family type (joint/nuclear) on aggressiveness profiles were not noticeable. Vegetarian diets and mixed-sex education act as protective factors in the development of aggressiveness in children, especially among boys. Extending investigations to populations differing in geography and cultural backgrounds are warranted to verify present results.

  13. Adult sex ratio effects on male survivorship of Drosophila melanogaster Meigen (Diptera, Drosophilidae Efeito da razão sexual de adultos na curva de sobrevivência de machos de Drosophila melanogaster Meigen (Diptera, Drosophilidae

    Directory of Open Access Journals (Sweden)

    Marcelo Costa

    2010-01-01

    Full Text Available The behavioral biology has a central role in evolutionary biology mainly because the antagonistic relations that occur in the sexual reproduction. One involves the effect of reproduction on the future life expectation. In this scenario, changes in male operational sex ratio could lead to an increase in mortality due to costs associated with excessive courtship and mating displays. Thus, this work experimentally altered the male sex ratio of Drosophila melanogaster Meigen, 1830, to determine its impact on mortality. The results indicated that mortality increases as the sex ratio changes, including modifications in the survivorship curve type and in the curve concavity, measured by entropy.A biologia comportamental tem um papel central na biologia evolutiva principalmente pelas relações antagônicas que ocorrem na reprodução sexuada. Uma destas relações envolve o efeito da reprodução sobre a expectativa de vida futura. Neste cenário, alterações na razão sexual operacional de machos podem levar a um aumento na mortalidade por causa dos custos associados com o excesso de displays de corte e cópulas. Neste sentido este trabalho alterou experimentalmente a razão sexual em machos de Drosophila melanogaster Meigen, 1830, para determinar os efeitos em termos de mortalidade. Os resultados indicam que a mortalidade aumenta a medida que a razão sexual se enviesa incluindo alterações no tipo de curva de sobrevivência e da concavidade da curva, medida pela entropia.

  14. In the Pursuit of Sons: Additional Births or Sex-Selective Abortion in Pakistan?

    Science.gov (United States)

    Zaidi, Batool; Morgan, S Philip

    2016-12-01

    Even though Pakistan is a highly patriarchal society, it has not featured prominently in studies focusing on sex-selective abortion and sex ratios at birth. But with fertility declining and existing strong son preference-Pakistan has one of the highest desired sex ratios in the world-how will Pakistani families respond? In the pursuit of sons, will they have additional children or resort to sex-selective abortions? Or is there evidence that the pursuit of sons is weakening? Using data from three rounds of the demographic and health survey, we show clear evidence of son preference in fertility intentions, patterns of contraceptive use and parity progression ratios. More specifically, we find pervasive evidence that Pakistanis continue childbearing to have a son, to have more than one son and to have at least one daughter. We do not find consistent and convincing evidence that sex ratios at birth (which indicate sex-selective abortion) are increasing.

  15. Weight-length Relationships, Gonadosomatic Indeces, Sex Ratios and Relative Weight of the Omani-Indian Oil sardine, Sardinella longiceps (Valenciennes1847) from Al-Seeb Area; Sultanate of Oman

    OpenAIRE

    Al-Jufaili Saud

    2011-01-01

    This study presents the weight-length relationship and spawning period of the Omani Indian Oil sardine Sardinella longiceps (Valenciennes 1847) which inhabits the near shore zone along the Omani coast. A total of 1744 specimens were collected between January 1997 to February 1998 from Al-Seeb; a suburban area situated by the sea in Muscat, Oman. Samples were obtained on a monthly basis from beach seine and gillnet catches. The female to male sex ratio was obtained to be 0.6. The monthly varia...

  16. [Seasonal variation patterns of NH4(+) -N/NO3(-) -N ratio and delta 15 NH4(+) value in rainwater in Yangtze River Delta].

    Science.gov (United States)

    Xie, Ying-Xin; Zhang, Shu-Li; Zhao, Xu; Xiong, Zheng-Qin; Xing, Guang-Xi

    2008-09-01

    By using a customized manual rainwater sampler made of polyvinyl chloride plastic, the molar ratio of NH4(+) -N/NO3(-) -N and the natural 15N abundance of NH4(+) (delta 15 NH4(+) in rainwater was monitored all year round from June 2003 to July 2005 at three observation sites (Changshu, Nanjing, and Hangzhou) in the Yangtze River Delta. The results indicated that at the three sites, the NH4(+) -N/NO3(-) -N ratio and the delta 15 NH4(+) value in rainwater had the similar seasonal variation trend, being more obvious in Changshu (rural monitoring type) site than in Nanjing (urban monitoring type) and Hangzhou (urban-rural monitoring type) sites. The NH4(+) -N/NO3(-) -N ratio peaked from early June to early August, declined gradually afterwards, and reached the bottom in winter; while the delta 15 NH4(+) value was negative from late June to mid-August, turned positive from late August to mid or late November, became negative again when winter dominated from December to March, but turned positive again in next May and negative again in next July. These seasonal variation patterns of NH4(+) -N/NO3(-) -N ratio and delta 15 NH4(+) value were found in relation to the application of chemical nitrogen fertilizers during different crop growth periods, and also, the alternation of seasons and the NH3 volatilization from other NH3 emission sources (including excrements of human and animals, nitrogen- polluted water bodies, and organic nitrogen sources, etc.), which could be taken as an indicator of defining the sources and form composition of NH4(+) in atmospheric wet deposition and the intensity of various terrestrial NH3 emission sources.

  17. Meerkat close calling patterns are linked to sex, social category, season and wind, but not fecal glucocorticoid metabolite concentrations.

    Directory of Open Access Journals (Sweden)

    Jelena Mausbach

    Full Text Available It is well established that animal vocalizations can encode information regarding a sender's identity, sex, age, body size, social rank and group membership. However, the association between physiological parameters, particularly stress hormone levels, and vocal behavior is still not well understood. The cooperatively breeding African meerkats (Suricata suricatta live in family groups with despotic social hierarchies. During foraging, individuals emit close calls that help maintain group cohesion. These contact calls are acoustically distinctive and variable in rate across individuals, yet, information on which factors influence close calling behavior is missing. The aim of this study was to identify proximate factors that influence variation in call rate and acoustic structure of meerkat close calls. Specifically, we investigated whether close calling behavior is associated with sex, age and rank, or stress hormone output (i.e., measured as fecal glucocorticoid metabolite (fGCM concentrations as individual traits of the caller, as well as with environmental conditions (weather and reproductive seasonality. To disentangle the effects of these factors on vocal behavior, we analyzed sound recordings and assessed fGCM concentrations in 64 wild but habituated meerkats from 9 groups during the reproductive and non-reproductive seasons. Dominant females and one-year old males called at significantly higher rates compared to other social categories during the reproductive season. Additionally, dominant females produced close calls with the lowest mean fundamental frequencies (F0 and the longest mean pulse durations. Windy conditions were associated with significantly higher call rates during the non-reproductive season. Fecal GCM concentrations were unrelated to close calling behavior. Our findings suggest that meerkat close calling behavior conveys information regarding the sex and social category of the caller, but shows no association with f

  18. Sex- and age-specific trends in antibiotic resistance patterns of Escherichia coli urinary isolates from outpatients.

    Science.gov (United States)

    McGregor, Jessina C; Elman, Miriam R; Bearden, David T; Smith, David H

    2013-02-22

    Urinary tract infections (UTIs) are one of the most common infections treated in ambulatory care settings, however the epidemiology differs by age and sex. The incidence of UTI is far greater in females than males, and infection in pediatric patients is more often due to anatomical abnormalities. The purpose of this research was to describe age- and sex-specific trends in antibiotic susceptibility to common urinary anti-infectives among urinary isolates of Escherichia coli from ambulatory primary care patients in a regional health maintenance organization. Clinical microbiology data were collected for all urine cultures from patients with visits to primary care clinics in a regional health maintenance organization between 2005 and 2010. The first positive culture for E. coli tested for antibiotic susceptibilities per patient per year was included in the analysis dataset. The frequency of susceptibility to ampicillin, amoxicillin-clavulanate, ciprofloxacin, nitrofurantoin, and trimethoprim/sulfamethoxazole (TMP/SMX) was calculated for male and female patients. The Cochrane-Mantel-Haenzel test was used to test for differences in age-stratified susceptibility to each antibiotic between males and females. A total of 43,493 E. coli isolates from 34,539 unique patients were identified for study inclusion. After stratifying by age, E. coli susceptibility to ampicillin, amoxicillin-clavulanate, ciprofloxacin, and nitrofurantoin differed significantly between males and females. However, the magnitude of the differences was less than 10% for all strata except amoxicillin-clavulanate susceptibility in E. coli isolated from males age 18-64 compared to females of the same age. We did not observe clinically meaningful differences in antibiotic susceptibility to common urinary anti-infectives among E. coli isolated from males versus females. These data suggest that male sex alone should not be used as an indication for empiric use of second-line broad-spectrum antibiotic agents

  19. Being both and acting 'man': exploring patterns of masculinisation among young same-sex-attracted men in Thailand.

    Science.gov (United States)

    de Lind van Wijngaarden, Jan W

    2014-01-01

    Twenty-five same-sex-attracted rural young Thai men were interviewed three times to investigate how their sexual subjectivity changed over an 18-month period after they completed high school and moved into a new life-phase. Many young men grew up with strong gender-based understandings of homosexuality, in which a masculine (top) partner is seen as complementing a feminine (bottom) partner. The discursive division between the masculine and feminine domains became increasingly blurred in the actual practice of dating, forcing the young men to develop new understandings of homosexuality and same-sex relations. The shift from a rural to urban environment, the use of the Internet and the experience of falling in love played important roles in this experimentation with new, increasingly masculine presentations of the self, also influenced by a modern urban masculine aesthetic. The paper concludes that the encounter between 'traditional' gender-based homosexuality and new ideas, in which masculine object-choice is important in defining sexual identity leads to a variety of fluid ideas and expressions. This process created confusion among some, and opportunities for exploration of new ways of defining sexual subjectivities among others.

  20. Evidence of oligogenic sex determination in the apple snail Pomacea canaliculata.

    Science.gov (United States)

    Yusa, Yoichi; Kumagai, Natsumi

    2018-02-26

    A small number of genes may interact to determine sex, but few such examples have been demonstrated in animals, especially through comprehensive mating experiments. The highly invasive apple snail Pomacea canaliculata is gonochoristic and shows a large variation in brood sex ratio, and the involvement of multiple genes has been suggested for this phenomenon. We conducted mating experiments to determine whether their sex determination involves a few or many genes (i.e., oligogenic or polygenic sex determination, respectively). Full-sib females or males that were born from the same parents were mated to an adult of the opposite sex, and the brood sex ratios of the parents and their offspring were investigated. Analysis of a total of 4288 offspring showed that the sex ratios of offspring from the full-sib females were variable but clustered into only a few values. Similar patterns were observed for the full-sib males, although the effect was less clear because fewer offspring were used (n = 747). Notably, the offspring sex ratios of all full-sib females in some families were nearly 0.5 (proportion of males) with little variation. These results indicate that the number of genotypes of the full-sibs, and hence genes involved in sex determination, is small in this snail. Such oligogenic systems may be a major sex-determining system among animals, especially those with variable sex ratios.

  1. The binding patterns of antisera to sex steroids and human gonadotropins on human and rhesus monkey spermatozoa.

    Science.gov (United States)

    Allag, I S; Das, R P; Roy, S

    1983-01-01

    The presence of different hormones on the surface of ejaculated spermatozoa was determined by immunofluorescence studies of the binding patterns of specific antisera to these hormones. There were striking similarities in the binding pattern of antisera to steroid hormones found on human and monkey spermatozoa. Assuming the intensity of fluorescence is proportional to the concentration of the hormone, concentrations of testosterone on the acrosomal and the postacrosomal regions were higher than levels of progesterone and estrogens.