THE CHERNOBYL ACCIDENT, THE MALE TO FEMALE RATIO AT BIRTH AND BIRTH RATES

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Victor Grech

2014-01-01

Full Text Available Introduction: The male:female ratio at birth (male births divided by total live births – M/T has been shown to increase in response to ionizing radiation due to gender-biased fetal loss, with excess female loss. M/T rose sharply in 1987 in central-eastern European countries following the Chernobyl accident in 1986. This study analyses M/T and births for the former Soviet Republics and for the countries most contaminated by the event. Methods: Annual birth data was obtained from the World Health Organisation. The countries with the highest exposure levels (by 137Cs were identified from an official publication of the International Atomic Energy Agency. All of the former Soviet states were also analysed and the periods before and after 1986 were compared. Results: Except for the Baltic States, all regions in the former USSR showed a significant rise in M/T from 1986. There were significant rises in M/T in the three most exposed (Belarus, Ukraine and the Russian Federation. The birth deficit in the post-Soviet states for the ten years following Chernobyl was estimated at 2,072,666, of which 1,087,924 are accounted by Belarus and Ukraine alone. Discussion: Chernobyl has resulted in the loss of millions of births, a process that has involved female even more than male fetuses. This is another and oft neglected consequence of widespread population radiation contamination.

Genomics and relative expression analysis identifies key genes associated with high female to male flower ratio in Jatropha curcas L.

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Gangwar, Manali; Sood, Hemant; Chauhan, Rajinder Singh

2016-04-01

Jatropha curcas, has been projected as a major source of biodiesel due to high seed oil content (42 %). A major roadblock for commercialization of Jatropha-based biodiesel is low seed yield per inflorescence, which is affected by low female to male flower ratio (1:25-30). Molecular dissection of female flower development by analyzing genes involved in phase transitions and floral organ development is, therefore, crucial for increasing seed yield. Expression analysis of 42 genes implicated in floral organ development and sex determination was done at six floral developmental stages of a J. curcas genotype (IC561235) with inherently higher female to male flower ratio (1:8-10). Relative expression analysis of these genes was done on low ratio genotype. Genes TFL1, SUP, AP1, CRY2, CUC2, CKX1, TAA1 and PIN1 were associated with reproductive phase transition. Further, genes CUC2, TAA1, CKX1 and PIN1 were associated with female flowering while SUP and CRY2 in female flower transition. Relative expression of these genes with respect to low female flower ratio genotype showed up to ~7 folds increase in transcript abundance of SUP, TAA1, CRY2 and CKX1 genes in intermediate buds but not a significant increase (~1.25 folds) in female flowers, thereby suggesting that these genes possibly play a significant role in increased transition towards female flowering by promoting abortion of male flower primordia. The outcome of study has implications in feedstock improvement of J. curcas through functional validation and eventual utilization of key genes associated with female flowering.

Mortality of tyrophagus putrescentiae (Schrank) females exposed to a high ratio of gamma-irradiated males as an index of radiation impact on sexual vigor of males

International Nuclear Information System (INIS)

Ignatowicz, S.

1990-01-01

A 40 or 60 krad dose of gamma radiation reduce slightly sexual activity of the males but male activity is greatly reduced as the radiation dose increases from 60 to 120 krad. Females of the mold mite, Tyrophagus, putrescentiae (Schrank), molested by males present at a 3:1 or 5:1 ratio live shorter than females kept with one male. The SAG test can be applied to compare sexual activity of males treated with different dosage of gamma irradiation

Effects of the distribution of female primates on the number of males.

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Laurel Mariah Carnes

Full Text Available The spatiotemporal distribution of females is thought to drive variation in mating systems, and hence plays a central role in understanding animal behavior, ecology and evolution. Previous research has focused on investigating the links between female spatiotemporal distribution and the number of males in haplorhine primates. However, important questions remain concerning the importance of spatial cohesion, the generality of the pattern across haplorhine and strepsirrhine primates, and the consistency of previous findings given phylogenetic uncertainty. To address these issues, we examined how the spatiotemporal distribution of females influences the number of males in primate groups using an expanded comparative dataset and recent advances in bayesian phylogenetic and statistical methods. Specifically, we investigated the effect of female distributional factors (female number, spatial cohesion, estrous synchrony, breeding season duration and breeding seasonality on the number of males in primate groups. Using bayesian approaches to control for uncertainty in phylogeny and the model of trait evolution, we found that the number of females exerted a strong influence on the number of males in primate groups. In a multiple regression model that controlled for female number, we found support for temporal effects, particularly involving female estrous synchrony: the number of males increases when females are more synchronously receptive. Similarly, the number of males increases in species with shorter birth seasons, suggesting that greater breeding seasonality makes defense of females more difficult for male primates. When comparing primate suborders, we found only weak evidence for differences in traits between haplorhines and strepsirrhines, and including suborder in the statistical models did not affect our conclusions or give compelling evidence for different effects in haplorhines and strepsirrhines. Collectively, these results demonstrate that

Brain arginine vasotocin and isotocin in breeding female three-spined sticklebacks (Gasterosteus aculeatus): the presence of male and egg deposition.

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Kulczykowska, Ewa; Kleszczyńska, Agnieszka

2014-08-01

Arginine vasotocin (AVT) and isotocin (IT) are fish hypothalamic nonapeptides involved in numerous social and reproductive behaviors. Vasotocinergic and isotocinergic fibers project to different brain areas where peptides act as neurotransmitters and/or neuromodulators. In this study, we measured whole brain levels of bioactive AVT and IT in breeding females of three-spined stickleback (Gasterosteus aculeatus) when they were kept with: (i) courting nest-owners, (ii) courting males that did not build the nest, (iii) non-courting males, and (iv) alone. Only some of the females kept with courting nest-owners deposited eggs. The highest and similar brain AVT levels were in those of females that did not deposit eggs, regardless of whether they were kept with non-courting or courting male, having the nest or not. The highest IT levels were in females that did not deposit eggs but only in those kept with courting male. We suggest that production of AVT in females' brain is stimulated by the presence of male in close proximity, irrespective of whether or not it displays courting behavior, but that of IT is stimulated by male courtship proxies. Moreover, presence of courting or non-courting male that stimulate IT or/and AVT producing neurones may be decisive for final oocyte maturation or egg deposition, because brain levels of both nonapeptides decrease after egg deposition. Similar AVT levels in brains of aggressive and non-aggressive individuals and lack of correlation between brain IT levels and aggressive behavior of females suggest that the nonapeptides are not related to females aggressiveness in three-spined sticklebacks. Copyright © 2014. Published by Elsevier Inc.

Natural selection for earlier male arrival to breeding grounds through direct and indirect effects in a migratory songbird

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Velmala, William; Helle, Samuli; Ahola, Markus P.; Klaassen, M.R.J.; Lehikoinen, Esa; Rainio, Kalle; Sirkia, Paivi M.; Laaksonen, Toni

2015-01-01

For migratory birds, the earlier arrival of males to breeding grounds is often expected to have fitness benefits. However, the selection differential on male arrival time has rarely been decomposed into the direct effect of male arrival and potential indirect effects through female traits. We

A diagnostic-ratio approach to measuring beliefs about the leadership abilities of male and female managers.

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Martell, R F; Desmet, A L

2001-12-01

This study departed from previous research on gender stereotyping in the leadership domain by adopting a more comprehensive view of leadership and using a diagnostic-ratio measurement strategy. One hundred and fifty-one managers (95 men and 56 women) judged the leadership effectiveness of male and female middle managers by providing likelihood ratings for 14 categories of leader behavior. As expected, the likelihood ratings for some leader behaviors were greater for male managers, whereas for other leader behaviors, the likelihood ratings were greater for female managers or were no different. Leadership ratings revealed some evidence of a same-gender bias. Providing explicit verification of managerial success had only a modest effect on gender stereotyping. The merits of adopting a probabilistic approach in examining the perception and treatment of stigmatized groups are discussed.

Facing aggression: cues differ for female versus male faces.

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Shawn N Geniole

Full Text Available The facial width-to-height ratio (face ratio, is a sexually dimorphic metric associated with actual aggression in men and with observers' judgements of aggression in male faces. Here, we sought to determine if observers' judgements of aggression were associated with the face ratio in female faces. In three studies, participants rated photographs of female and male faces on aggression, femininity, masculinity, attractiveness, and nurturing. In Studies 1 and 2, for female and male faces, judgements of aggression were associated with the face ratio even when other cues in the face related to masculinity were controlled statistically. Nevertheless, correlations between the face ratio and judgements of aggression were smaller for female than for male faces (F(1,36 = 7.43, p = 0.01. In Study 1, there was no significant relationship between judgements of femininity and of aggression in female faces. In Study 2, the association between judgements of masculinity and aggression was weaker in female faces than for male faces in Study 1. The weaker association in female faces may be because aggression and masculinity are stereotypically male traits. Thus, in Study 3, observers rated faces on nurturing (a stereotypically female trait and on femininity. Judgements of nurturing were associated with femininity (positively and masculinity (negatively ratings in both female and male faces. In summary, the perception of aggression differs in female versus male faces. The sex difference was not simply because aggression is a gendered construct; the relationships between masculinity/femininity and nurturing were similar for male and female faces even though nurturing is also a gendered construct. Masculinity and femininity ratings are not associated with aggression ratings nor with the face ratio for female faces. In contrast, all four variables are highly inter-correlated in male faces, likely because these cues in male faces serve as "honest signals".

Facing aggression: cues differ for female versus male faces.

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Geniole, Shawn N; Keyes, Amanda E; Mondloch, Catherine J; Carré, Justin M; McCormick, Cheryl M

2012-01-01

The facial width-to-height ratio (face ratio), is a sexually dimorphic metric associated with actual aggression in men and with observers' judgements of aggression in male faces. Here, we sought to determine if observers' judgements of aggression were associated with the face ratio in female faces. In three studies, participants rated photographs of female and male faces on aggression, femininity, masculinity, attractiveness, and nurturing. In Studies 1 and 2, for female and male faces, judgements of aggression were associated with the face ratio even when other cues in the face related to masculinity were controlled statistically. Nevertheless, correlations between the face ratio and judgements of aggression were smaller for female than for male faces (F(1,36) = 7.43, p = 0.01). In Study 1, there was no significant relationship between judgements of femininity and of aggression in female faces. In Study 2, the association between judgements of masculinity and aggression was weaker in female faces than for male faces in Study 1. The weaker association in female faces may be because aggression and masculinity are stereotypically male traits. Thus, in Study 3, observers rated faces on nurturing (a stereotypically female trait) and on femininity. Judgements of nurturing were associated with femininity (positively) and masculinity (negatively) ratings in both female and male faces. In summary, the perception of aggression differs in female versus male faces. The sex difference was not simply because aggression is a gendered construct; the relationships between masculinity/femininity and nurturing were similar for male and female faces even though nurturing is also a gendered construct. Masculinity and femininity ratings are not associated with aggression ratings nor with the face ratio for female faces. In contrast, all four variables are highly inter-correlated in male faces, likely because these cues in male faces serve as "honest signals".

Facing Aggression: Cues Differ for Female versus Male Faces

Science.gov (United States)

Geniole, Shawn N.; Keyes, Amanda E.; Mondloch, Catherine J.; Carré, Justin M.; McCormick, Cheryl M.

2012-01-01

The facial width-to-height ratio (face ratio), is a sexually dimorphic metric associated with actual aggression in men and with observers' judgements of aggression in male faces. Here, we sought to determine if observers' judgements of aggression were associated with the face ratio in female faces. In three studies, participants rated photographs of female and male faces on aggression, femininity, masculinity, attractiveness, and nurturing. In Studies 1 and 2, for female and male faces, judgements of aggression were associated with the face ratio even when other cues in the face related to masculinity were controlled statistically. Nevertheless, correlations between the face ratio and judgements of aggression were smaller for female than for male faces (F1,36 = 7.43, p = 0.01). In Study 1, there was no significant relationship between judgements of femininity and of aggression in female faces. In Study 2, the association between judgements of masculinity and aggression was weaker in female faces than for male faces in Study 1. The weaker association in female faces may be because aggression and masculinity are stereotypically male traits. Thus, in Study 3, observers rated faces on nurturing (a stereotypically female trait) and on femininity. Judgements of nurturing were associated with femininity (positively) and masculinity (negatively) ratings in both female and male faces. In summary, the perception of aggression differs in female versus male faces. The sex difference was not simply because aggression is a gendered construct; the relationships between masculinity/femininity and nurturing were similar for male and female faces even though nurturing is also a gendered construct. Masculinity and femininity ratings are not associated with aggression ratings nor with the face ratio for female faces. In contrast, all four variables are highly inter-correlated in male faces, likely because these cues in male faces serve as “honest signals”. PMID:22276184

Female harbor seal (Phoca vitulina) behavioral response to playbacks of underwater male acoustic advertisement displays.

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Matthews, Leanna P; Blades, Brittany; Parks, Susan E

2018-01-01

During the breeding season, male harbor seals ( Phoca vitulina ) make underwater acoustic displays using vocalizations known as roars. These roars have been shown to function in territory establishment in some breeding areas and have been hypothesized to be important for female choice, but the function of these sounds remains unresolved. This study consisted of a series of playback experiments in which captive female harbor seals were exposed to recordings of male roars to determine if females respond to recordings of male vocalizations and whether or not they respond differently to roars from categories with different acoustic characteristics. The categories included roars with characteristics of dominant males (longest duration, lowest frequency), subordinate males (shortest duration, highest frequency), combinations of call parameters from dominant and subordinate males (long duration, high frequency and short duration, low frequency), and control playbacks of water noise and water noise with tonal signals in the same frequency range as male signals. Results indicate that overall females have a significantly higher level of response to playbacks that imitate male vocalizations when compared to control playbacks of water noise. Specifically, there was a higher level of response to playbacks representing dominant male vocalization when compared to the control playbacks. For most individuals, there was a greater response to playbacks representing dominant male vocalizations compared to playbacks representing subordinate male vocalizations; however, there was no statistical difference between those two playback types. Additionally, there was no difference between the playbacks of call parameter combinations and the controls. Investigating female preference for male harbor seal vocalizations is a critical step in understanding the harbor seal mating system and further studies expanding on this captive study will help shed light on this important issue.

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

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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.

Aedes albopictus (Skuse) males in laboratory and semi-field cages: release ratios and mating competitiveness.

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Madakacherry, Odessa; Lees, Rosemary Susan; Gilles, Jeremie Roger Lionel

2014-04-01

To control the container-breeding mosquito and major vector of dengue and chikungunya Aedes albopictus, the sterile insect technique (SIT) is proposed as a component of integrated vector management programs in endemic areas. For the technique to be successful, released males, sterilized with 35 Gy of ionizing radiation during the pupal stage, must be able to compete for mating opportunities with wild counterparts and successfully copulate with wild females to induce sterility in the population. Any reduction in competitiveness can be compensated for by increasing the ratio of released sterile to wild males, a ratio which must be optimized for effectiveness and efficiency. Fruit fly SIT programs use field enclosures to test the competitiveness of sterile males to monitor the quality of the colony and adjust release ratios. This is laborious and time consuming, and for mosquito programs it would be advantageous if similarly useful results could be obtained by smaller scale laboratory tests, conducted on a more regular basis. In the present study we compared the competitiveness, as measured by hatching rate of resulting egg batches, of irradiated males measured in small and large laboratory cages and semi-field enclosures in a greenhouse setting, when competing in a 1:1, 3:1, and 5:1 ratio with fertile males. The sterile males were found to be equally competitive when compared to unirradiated counterparts, and a 5:1 ratio was sufficient to reduce, but not eliminate, the fertility of the female populations, irrespective of cage size. Variability in hatch rate in eggs laid by individual females and so-called indeterminate matings, when we could not be certain whether a female had mated a fertile or a sterile male, could be investigated by closer investigation of mating status and the frequency of multiple matings in Ae. albopictus. The laboratory results are encouraging for the effectiveness of the SIT using irradiated males of this species, and we support further

Testosterone-dependency of male solo song in a duetting songbird--evidence from females.

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Voigt, Cornelia; Leitner, Stefan

2013-01-01

For male songbirds of the temperate zone there is a tight link between seasonal song behaviour and circulating testosterone levels. Such a relationship does not seem to hold for tropical species where singing can occur year-round and breeding seasons are often extended. White-browed sparrow weavers (Plocepasser mahali) are cooperatively breeding songbirds with a dominant breeding pair and male and female subordinates found in eastern and southern Africa. Each group defends an all-purpose territory year-round. While all group members sing duets and choruses, the most dominant male additionally sings a solo song that comprises a distinct and large syllable repertoire. Previous studies suggested this type of song being associated with reproduction but failed to support a relationship with males' circulating testosterone levels. The present study aimed to investigate the steroid hormone sensitivity of the solo song in more detail. We found that dominant males had significantly higher circulating testosterone levels than subordinates during the early and late breeding seasons. No changes in solo song characteristics were found between both time points. Further, experimental implantation of captive adult females with exogenous testosterone induced solo singing within one week of treatment. Such females produced male-typical song regarding overall structure and syllable composition. Sex differences existed, however, concerning singing activity, repertoire size and temporal organisation of song. These results suggest that solo singing in white-browed sparrow weavers is under the control of gonadal steroid hormones. Moreover, the behaviour is not male-specific but can be activated in females under certain conditions. Copyright © 2012 Elsevier Inc. All rights reserved.

The association between living through a prolonged economic depression and the male:female birth ratio--a longitudinal study from Cuba, 1960-2008.

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Venero Fernández, Silvia Josefina; Medina, Ramon Suárez; Britton, John; Fogarty, Andrew W

2011-12-15

The Trivers-Willard hypothesis suggests that populations respond to scarcity by decreasing the ratio of males to females at livebirth. Cuba experienced an extreme economic depression in the 1990s called the "special period." Using time-series analysis, the authors studied the impact of this event on the male:female sex ratio at birth in Cuba from 1960 to 2008. From 1990 to 1993, the per capita gross domestic product in Cuba decreased by 36%. By use of a definition of the special period from 1991 to 1998, there was a prolonged increase in the male:female ratio of livebirths during this period of economic depression (P Cuba, contrary to the Trivers-Willard hypothesis, the human population responded to conditions of scarcity by increasing the ratio of males to females at livebirth. These data may be relevant in the modeling of demographic projections in countries that experience prolonged economic depression and in understanding adaptive human reproductive responses to environmental change.

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

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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.

Male Rock Sparrow (Petronia petronia) Nest Defence Correlates with Female Ornament Size

DEFF Research Database (Denmark)

Griggio, Matteo; Matessi, Giuliano; Pilastro, Andrea

2003-01-01

We investigated the relationship between male nest defence and female breast patch size in an alpine population of rock sparrow (Petronia petronia) in northern Italy. We presented a mounted weasel (Mustela nivalis), a common nest predator, to 28 pairs breeding in nest boxes, with 12-13-d-old nest......We investigated the relationship between male nest defence and female breast patch size in an alpine population of rock sparrow (Petronia petronia) in northern Italy. We presented a mounted weasel (Mustela nivalis), a common nest predator, to 28 pairs breeding in nest boxes, with 12-13-d...... defence factor was significantly related only to female breast patch size. We argue that male rock sparrows apparently make parental investment decisions according to their mate's quality, and examine possible alternative hypotheses....

Male mice ultrasonic vocalizations enhance female sexual approach and hypothalamic kisspeptin neuron activity.

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Asaba, Akari; Osakada, Takuya; Touhara, Kazushige; Kato, Masahiro; Mogi, Kazutaka; Kikusui, Takefumi

2017-08-01

Vocal communication in animals is important for ensuring reproductive success. Male mice emit song-like "ultrasonic vocalizations (USVs)" when they encounter female mice, and females show approach to the USVs. However, it is unclear whether USVs of male mice trigger female behavioral and endocrine responses in reproduction. In this study, we first investigated the relationship between the number of deliveries in breeding pairs for 4months and USVs syllables emitted from those paired males during 3min of sexual encounter with unfamiliar female mice. There was a positive correlation between these two indices, which suggests that breeding pairs in which males could emit USVs more frequently had more offspring. Further, we examined the effect of USVs of male mice on female sexual behavior. Female mice showed more approach behavior towards vocalizing males than devocalized males. Finally, to determine whether USVs of male mice could activate the neural system governing reproductive function in female mice, the activation of kisspeptin neurons, key neurons to drive gonadotropin-releasing hormone neurons in the hypothalamus, was examined using dual-label immunocytochemistry with cAMP response element-binding protein phosphorylation (pCREB). In the arcuate nucleus (Arc), the number of kisspeptin neurons expressing pCREB significantly increased after exposure to USVs of male as compared with noise exposure group. In conclusion, our results suggest that USVs of male mice promote fertility in female mice by activating both their approaching behavior and central kisspeptin neurons. Copyright © 2017 Elsevier Inc. All rights reserved.

Facing Aggression: Cues Differ for Female versus Male Faces

OpenAIRE

Geniole, Shawn N.; Keyes, Amanda E.; Mondloch, Catherine J.; Carr?, Justin M.; McCormick, Cheryl M.

2012-01-01

The facial width-to-height ratio (face ratio), is a sexually dimorphic metric associated with actual aggression in men and with observers' judgements of aggression in male faces. Here, we sought to determine if observers' judgements of aggression were associated with the face ratio in female faces. In three studies, participants rated photographs of female and male faces on aggression, femininity, masculinity, attractiveness, and nurturing. In Studies 1 and 2, for female and male faces, judge...

When the ball is in the female's court: How the scramble-competition mating system of the North American red squirrel has shaped male physiology and testosterone dynamics.

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Boonstra, Rudy; Dušek, Adam; Lane, Jeffrey E; Boutin, Stan

2017-10-01

Male reproductive success in most mammals is determined by their success in direct inter-male competition through aggression and conflict, resulting in female-defense mating systems being predominant. This is linked to male testosterone levels and its dynamics. However, in certain environments, a scramble-competition mating system has evolved, where female reproductive behavior takes precedence and male testosterone dynamics are unlikely to be related to inter-male competition. We studied the North American red squirrel (Tamiasciurus hudsonicus), a species with a well-established scramble-competition system. Using an ACTH hormonal challenge protocol as a proxy for competitive interactions, we compared the testosterone dynamics in breeding males in late winter with that in nonbreeding males in late spring in the Yukon. To gain an integrated picture of their physiological state, we also assessed changes in their stress response, body mass, energy mobilization, and indices of immune function. Testosterone levels at the base bleed were high in breeding males (2.72ng/mL) and virtually absent in non-breeding males (0.04ng/mL). Breeding males were in better condition (heavier body mass, higher hematocrit, and higher erythrocytes), had higher indices of immune function (neutrophil:lymphocyte ratio), but a similar ability to mobilize energy (glucose) compared with non-breeding males. Though total cortisol was higher in non-breeding males, free cortisol was twice as high in breeding males as their corticosteroid binding globulin levels were half as high. In response to the ACTH challenge, testosterone levels in breeding males declined 49% over the first hour and increased 36% over the next hour; in non-breeding males levels showed no change. Free cortisol increased only modestly (26% in breeding males; 23% in non-breeding males). Glucose levels changed similarly in breeding and nonbreeding males, declining for the first 30min and then increasing for the next 60min. Thus

Construction of a male sterility system for hybrid rice breeding and seed production using a nuclear male sterility gene.

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Chang, Zhenyi; Chen, Zhufeng; Wang, Na; Xie, Gang; Lu, Jiawei; Yan, Wei; Zhou, Junli; Tang, Xiaoyan; Deng, Xing Wang

2016-12-06

The breeding and large-scale adoption of hybrid seeds is an important achievement in agriculture. Rice hybrid seed production uses cytoplasmic male sterile lines or photoperiod/thermo-sensitive genic male sterile lines (PTGMS) as female parent. Cytoplasmic male sterile lines are propagated via cross-pollination by corresponding maintainer lines, whereas PTGMS lines are propagated via self-pollination under environmental conditions restoring male fertility. Despite huge successes, both systems have their intrinsic drawbacks. Here, we constructed a rice male sterility system using a nuclear gene named Oryza sativa No Pollen 1 (OsNP1). OsNP1 encodes a putative glucose-methanol-choline oxidoreductase regulating tapetum degeneration and pollen exine formation; it is specifically expressed in the tapetum and miscrospores. The osnp1 mutant plant displays normal vegetative growth but complete male sterility insensitive to environmental conditions. OsNP1 was coupled with an α-amylase gene to devitalize transgenic pollen and the red fluorescence protein (DsRed) gene to mark transgenic seed and transformed into the osnp1 mutant. Self-pollination of the transgenic plant carrying a single hemizygous transgene produced nontransgenic male sterile and transgenic fertile seeds in 1:1 ratio that can be sorted out based on the red fluorescence coded by DsRed Cross-pollination of the fertile transgenic plants to the nontransgenic male sterile plants propagated the male sterile seeds of high purity. The male sterile line was crossed with ∼1,200 individual rice germplasms available. Approximately 85% of the F1s outperformed their parents in per plant yield, and 10% out-yielded the best local cultivars, indicating that the technology is promising in hybrid rice breeding and production.

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.

Pair housing differentially affects motivation to self-administer cocaine in male and female rats.

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Westenbroek, Christel; Perry, Adam N; Becker, Jill B

2013-09-01

Female rats exhibit greater intake and motivation to self-administer cocaine. In females but not males, isolation by itself is a stressor, which could lead to increased drug intake. Therefore, we hypothesized that social housing would buffer against stress and reduce the motivation to self-administer cocaine primarily in females. Male and female Sprague-Dawley rats were housed individually or in same-sex pairs. The individually housed rats and one of each pair were allowed to self-administer (SA) a low dose of cocaine (0.2 mg/kg/inf) on a fixed ratio (FR1) schedule for one week. Motivation for cocaine SA was measured for an additional 2 weeks on a progressive ratio schedule. Isolated females had greater cocaine-intake on the FR1 schedule and greater motivation to take cocaine than males. Pair-housing in females, but not males, attenuated the motivation to take cocaine. Isolated females, but not males, showed escalation of their motivation to take cocaine, which was attenuated by pair housing of females. Concluding, the motivation to take cocaine escalates in females but not males, and pair-housing of females attenuates this escalation. Copyright © 2013 Elsevier B.V. All rights reserved.

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

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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.

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

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João Fabrício Mota Rodrigues

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

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

Science.gov (United States)

Rodrigues, João Fabrício Mota; Coelho, Marco Túlio Pacheco

2016-01-01

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

The Great Recession of 2007 in the United States and the male: female ratio at birth

OpenAIRE

Grech, Victor

2015-01-01

OBJECTIVE: Male live births slightly exceed female live births by approximately 3%. The ratio of male to total live births is conventionally represented as M/F. Many factors have been shown to affect M/F, mainly privation, toxins, and stress, all of which reduce M/F. Population stress may be engendered by natural phenomena such as earthquakes and man-made events such as short wars, terrorist attacks, and contracting economies. This study was conducted to ascertain whether the onset of the "Gr...

Spacing behaviour of juvenile corn mice, Calomys musculinus , at the beginning of the breeding period, in absence of adult males

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Steinmann, Andrea; Priotto, José; Sommaro, Lucia; Polop, Jaime

2006-05-01

This research was carried out to examine the hypothesis that the absence of fathers promotes a different spacing behaviour in juveniles Calomys musculinus at the beginning of the breeding period. The study was carried out in four 0.25-ha enclosures (two control and two experimental), in a natural pasture, between November 2003 and February 2004. In this study the fathers were removed from the experimental enclosures after juveniles were born. Home-range size depended on sex of juveniles and treatment (father removal). In control and experimental enclosures, female home-range sizes were always smaller than male home-ranges. Male home-ranges were always larger in experimental enclosures than in control enclosures. Treatment and overlap type (intra- and inter-sexual) were not independent. The overlap proportions of male home-ranges were greatest in experimental enclosures than in control enclosures, in both the overlap types (male/male, males/females). The intra- (females/females) and inter-sexual (females/males) overlap proportions of female home-ranges were independent of treatment. In C. musculinus, at the beginning of the breeding period and in absence of adult males, juvenile males increase their home-range size and therefore the degree of inter- and intra-sexual home-range overlap as a mechanism for enlarging the number of receptive females that they encounter.

Climate change is associated with male:female ratios of fetal deaths and newborn infants in Japan

DEFF Research Database (Denmark)

Fukuda, Misao; Fukuda, Kiyomi; Shimizu, Takashi

2014-01-01

. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Yearly sex ratios of fetal deaths and newborn infants and monthly fetal death rates and sex ratios of newborn infants. RESULT(S): A statistically significant positive association was found between yearly temperature differences and sex ratios of fetal deaths......; a statistically significant negative association was found between temperature differences and sex ratios of newborn infants from 1968 to 2012, and between sex ratios of births and of fetal deaths. The sex ratios of fetal deaths have been increasing steadily along with temperature differences, whereas the sex......OBJECTIVE: To evaluate whether climate change is associated with male:female ratios (sex ratios) of fetal deaths and births in Japan. DESIGN: A population-based cohort study. SETTING: Not applicable. PATIENT(S): Newborn infants and fetuses spontaneously aborted after 12 weeks of gestation...

Mate choice for a male carotenoid-based ornament is linked to female dietary carotenoid intake and accumulation

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Toomey Matthew B

2012-01-01

Full Text Available Abstract Background The coevolution of male traits and female mate preferences has led to the elaboration and diversification of sexually selected traits; however the mechanisms that mediate trait-preference coevolution are largely unknown. Carotenoid acquisition and accumulation are key determinants of the expression of male sexually selected carotenoid-based coloration and a primary mechanism maintaining the honest information content of these signals. Carotenoids also influence female health and reproduction in ways that may alter the costs and benefits of mate choice behaviours and thus provide a potential biochemical link between the expression of male traits and female preferences. To test this hypothesis, we manipulated the dietary carotenoid levels of captive female house finches (Carpodacus mexicanus and assessed their mate choice behavior in response to color-manipulated male finches. Results Females preferred to associate with red males, but carotenoid supplementation did not influence the direction or strength of this preference. Females receiving a low-carotenoid diet were less responsive to males in general, and discrimination among the colorful males was positively linked to female plasma carotenoid levels at the beginning of the study when the diet of all birds was carotenoid-limited. Conclusions Although female preference for red males was not influenced by carotenoid intake, changes in mating responsiveness and discrimination linked to female carotenoid status may alter how this preference is translated into choice. The reddest males, with the most carotenoid rich plumage, tend to pair early in the breeding season. If carotenoid-related variations in female choice behaviour shift the timing of pairing, then they have the potential to promote assortative mating by carotenoid status and drive the evolution of carotenoid-based male plumage coloration.

Captive breeding of the white rhinoceros, Ceratotherium simum, and the Cape buffalo, Syncerus caffer : research communication

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J.D. Skinner

2006-09-01

Full Text Available Breeding records of 40 white rhinoceros and 155 Cape buffalo were analysed. Three rhinoceros cows bred in captivity, themselves conceived for the first time at 84, 87 and 95 months of age, respectively. Rhinoceros cows breed throughout the year. There is no evidence of a relationship between calving interval and month of birth. Calving intervals were normally distributed about the mean of 34 months and there were no significant differences between bulls, cows or sex of calf. There was no difference in the sex ratio of calves born to young cows nor older cows. The male:female ratio of the calves was Younger cows did not have shorter birth intervals. Although captive Cape buffaloes breed throughout the year, there is a preponderance of births in midsummer. There was some evidence that larger cows produce heavier calves and that season of birth may influence birth weight. Male calves weighed 41.20 + 0.68 kg vs 39.00 + 0.73 kg (range 24-60 kg for female calves but this difference was not significant. Calving intervals were normally distributed about the mean of 395 days and the male:female ratio of the calves was 1:1.2.

Females lead population collapse of the endangered Hawaii creeper.

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Leonard A Freed

Full Text Available Population collapses result from drastic environmental changes, but the sexes may differ in vulnerability. Collapse of the endangered Hawaii creeper (Oreomystis mana at Hakalau Forest National Wildlife Refuge resulted from food limitation associated with increased numbers of an introduced bird (Japanese white-eye, Zosterops japonicus, which competes with the creeper for food. Both creeper sexes had stunted bill growth and the greatest change in molt of native species in the community. With a surge in numbers of white-eyes, a recent cohort of adult females had very low survival after breeding, while adult males from the same cohort, and older females and males, continued to have high survival. Lower female survival resulted in a significantly more male-biased adult sex ratio. Recent low female survival was based on a great cost of reproduction, indicated by molt-breeding overlap that was previously avoided, and lower fat during the lengthy fledgling period. The difference in female survival between cohorts was associated with stunted bills from being reared in and then breeding in an increasingly poor food environment. Trend analysis of survey data indicate that the bird is declining throughout the refuge, with males being 72-80% of adults left six years after the white-eye increased. Competition over time was consistent with that previously documented over space on the Island of Hawaii. Adaptive management to recover the bird in this protected area needs to focus on improving both adult female survival and the adult sex ratio.

Females lead population collapse of the endangered Hawaii creeper.

Science.gov (United States)

Freed, Leonard A; Cann, Rebecca L

2013-01-01

Population collapses result from drastic environmental changes, but the sexes may differ in vulnerability. Collapse of the endangered Hawaii creeper (Oreomystis mana) at Hakalau Forest National Wildlife Refuge resulted from food limitation associated with increased numbers of an introduced bird (Japanese white-eye, Zosterops japonicus), which competes with the creeper for food. Both creeper sexes had stunted bill growth and the greatest change in molt of native species in the community. With a surge in numbers of white-eyes, a recent cohort of adult females had very low survival after breeding, while adult males from the same cohort, and older females and males, continued to have high survival. Lower female survival resulted in a significantly more male-biased adult sex ratio. Recent low female survival was based on a great cost of reproduction, indicated by molt-breeding overlap that was previously avoided, and lower fat during the lengthy fledgling period. The difference in female survival between cohorts was associated with stunted bills from being reared in and then breeding in an increasingly poor food environment. Trend analysis of survey data indicate that the bird is declining throughout the refuge, with males being 72-80% of adults left six years after the white-eye increased. Competition over time was consistent with that previously documented over space on the Island of Hawaii. Adaptive management to recover the bird in this protected area needs to focus on improving both adult female survival and the adult sex ratio.

Terrorist attacks and the male-to-female ratio at birth: The Troubles in Northern Ireland, the Rodney King riots, and the Breivik and Sandy Hook shootings.

Science.gov (United States)

Grech, Victor

2015-12-01

Males are usually born in excess of females. The ratio is often expressed as M/F (male divided by total births). A wide variety of factors have been shown to influence M/F. Terrorist attacks reduce M/F. This study was carried out in order to ascertain whether individual terrorist attacks influenced M/F in relevant populations. The following events were studied: the Troubles in Northern Ireland, the Los Angeles Riots (the Rodney King affair), the Breivik shooting (Norway), and the Sandy Hook shooting (Connecticut). Northern Ireland M/F was significantly lower during the Troubles (1969-1998) than during the period before (p=0.0006). There was a very sharp dip in 1978 (p≤0.004) during this particular year of renewed violence and heavy civilian attacks. Rodney King riots-late April 1992 M/F dipped significantly in August 1992, 4months after the riots (p=0.044). Breivik Shooting-22/07/2011 M/F dipped significantly in December 2011, 5months after the event (p=0.004). Sandy Hook Shooting-14/12/2012 M/F dipped significantly in April 2013, 4months after the event (p=0.009). M/F dips follow catastrophic or tragic events if these are felt to be momentous enough by a given population. All of the above events caused significant population stress. The M/F dips noted may have been caused by population stress which is known to lead to the culling of frail/small male foetuses. The dips noted are comparable to a substantial proportion of quoted values for perinatal mortality, potentially elevating this a public health issue. 1. The male-to-female ratio at birth is decreased by stressful events. 2. This is due to an excess of male foetal losses in established pregnancies. 3. Such losses in response to acute events are transient. 4. This ratio may be a useful indicator of population stress. RESEARCH DIRECTIONS: 1. Gender ratios in populations could be routinely monitored in order to assess the impact of stressful events that may reduce the male-to-female birth ratio. Copyright �

Immunocompetence of breeding females is sensitive to cortisol levels but not to communal rearing in the degu (Octodon degus).

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Ebensperger, Luis A; León, Cecilia; Ramírez-Estrada, Juan; Abades, Sebastian; Hayes, Loren D; Nova, Esteban; Salazar, Fabián; Bhattacharjee, Joydeep; Becker, María Inés

2015-03-01

One hypothesis largely examined in social insects is that cooperation in the context of breeding benefits individuals through decreasing the burden of immunocompetence and provide passive immunity through social contact. Similarly, communal rearing in social mammals may benefit adult female members of social groups by reducing the cost of immunocompetence, and through the transfer of immunological compounds during allonursing. Yet, these benefits may come at a cost to breeders in terms of a need to increase investment in individual immunocompetence. We examined how these potential immunocompetence costs and benefits relate to reproductive success and survival in a natural population of the communally rearing rodent, Octodon degus. We related immunocompetence (based on ratios of white blood cell counts, total and specific immunoglobulins of G isotype titers) and fecal glucocorticoid metabolite (FGC) levels of adults immunized with hemocyanin from the mollusk Concholepas concholepas to measures of sociality (group size) and communal rearing (number of breeding females). Offspring immunocompetence was quantified based on circulating levels of the same immune parameters. Neither female nor offspring immunocompetence was influenced by communal rearing or sociality. These findings did not support that communal rearing and sociality enhance the ability of females to respond to immunological challenges during lactation, or contribute to enhance offspring condition (based on immunocompetence) or early survival (i.e., to 3months of age). Instead, levels of humoral and cellular components of immunocompetence were associated with variation in glucorcorticoid levels of females. We hypothesize that this covariation is driven by physiological (life-history) adjustments needed to sustain breeding. Copyright © 2014 Elsevier Inc. All rights reserved.

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

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

2013-01-01

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

Differences in personality traits between male-to-female and female-to-male gender identity disorder subjects.

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Miyajima, Eiichi; Taira, Naoki; Koda, Munenaga; Kondo, Tsuyoshi

2014-12-15

The present study aimed to investigate differences in personality traits among male-to-female (MtF), female-to-male (FtM) gender identity disorder (GID) subjects and non-transsexual male (M) and female (F) controls. Subjects were 72 MtF and 187 FtM GID subjects without psychiatric comorbidities together with 184 male and 159 female non-transsexual controls. Personality traits were assessed using a short version of the Temperament and Character Inventory (TCI-125). Group comparisons were made by two-way ANOVA. Statistical significances were observed as follows: 1) lower novelty seeking in FtM than in M or MtF, 2) higher reward dependence in FtM than in M, 3) higher cooperativeness in FtM than in M or MtF, 4) the highest self-transcendence in MtF among all the groups. The highest self-transcendence in MtF subjects may reflect their vulnerable identity and constrained adaptation to society as the minority. Nevertheless, higher reward dependence and cooperativeness in FtM subjects can be related to more determined motivation for the treatments of GID and might promise better social functioning and adjustment than MtF subjects. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Professional recognition of female and male doctors.

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Bruguera, M; Arrizabalaga, P; Londoño, M C; Padrós, J

2014-03-01

The awards for the excellence of the Official College of Physicians of Barcelona (COMB) were instituted in 2004 to recognize the excellence of the professional exercise. The winners are yearly chosen by juries appointed by the board of government, whose members propose for the award doctors who, in their opinion, have an exemplary professional and human behaviour. The number of male and female doctors who have obtained this recognition has been analysed in relation with the sex distribution in the juries. Likewise it has been compared the ratios men-to-women of those who have been rewarded and this ratio among physicians of more than 45 years. Between the awarded physicians the ratio men-to-women was of 2.7/1 (range, from 1.2/1 for awardees in primary care to 6/1 in research). The men-to-women ratio among those who were awarded was in parallel to the man-to-women ratios of the juries. The ratio between men and women among members of the COMB of more than 45 years was 1.4/1, whereas in those who were awarded it was of 2.7/1. The increase in the proportion of women in the juries in the last four years has been followed by an increase in the number of female physicians awarded. This data demonstrates that the predominance of male doctors among those who were awarded does not depend so much on the age factor, but basically on the proportion of male and female doctors in the juries. Copyright © 2013 Elsevier España, S.L. All rights reserved.

Characters analysis of genetic improvement at the males population from Romanian Mioritic Shepherd Dog breed

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Dorel Dronca

2017-05-01

Full Text Available The aim of this paper was to analyze, within a group of 26 males from Romanian Mioritic Shepherd Dog breed, 13 characters of genetically improved, characters stipulated in, „Selection sheet and body measurements for Romanian shepherds".The animals were registered with the Romanian Mioritic Association Club fromRomania.  Romanian Mioritic Shepherd Dog, was selected from a natural population breed inCarpathian Mountains. In order to develop a genetic improvement program at this effective of 26 males from Romanian Sheperd Dog breed, found in evidence of Romanian Mioritic Association Club from Romania, should be considered the following conclusions on variance those 13 characters studied in this paper, respectively, the variability was middle for the width of skull and ear  and low for the other 11 characters analyzed. Also, this paper highlighted the following reports of the characters analyzed at the males taken in the study: the ratio between the average of length and width skull was 1.005:1, the ratio between the average of length skull and the average of length muzzle was 1.31:1 and between average of the width of skull and the muzzle was 1.82:1. By Comparing between them length, width and depth of muzzle, resulted a ratio of 1.38:1:1.10.

SECULAR TRENDS AND LATITUDE GRADIENTS IN THE MALE-FEMALE RATIO AT BIRTH IN YUGOSLAVIA AND THE EX-YUGOSLAVIAN STATES

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Victor Grech

2013-01-01

Full Text Available Background: 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 approximates 0.515. Methods: Annual national data for Yugoslavia and the post-Yugoslavia States for male and female live births were obtained from the World Health Organisation and analysed with contingency tables. Results: This study analysed 22,020,729 live births. There was a increasing trend in M/F prior to the breakup of the former Yugoslavia (1950–1990, p = 0.002, followed by a decreasing trend after 1990 (p = 0.02. A latitude gradient was also noted, with more males being born in southern, warmer latitudes (p < 0.0001. There was an overall excess of 42,753 male births based on an anticipated M/F of 0.515. Conclusion: M/F is decreasing in this region, similar to the rest of Europe and North America. A latitude gradient is also present with more males being born in warmer (more Southern latitudes (p < 0.0001, even in this small region and over the short time-frame studied.

Daily movements of female white-tailed deer relative to parturition and breeding.

Energy Technology Data Exchange (ETDEWEB)

Gino J. D' Angelo; Christopher E. Comer; John C. Kilgo; Cory D. Drennan; David A. Osborn; Karl V. Miller

2005-10-01

Abstract: To assess how white-tailed deer (Odocoileus virginianus) herd demographics influence reproductive behaviors, we examined 24-h diel movements of female whitetailed deer relative to parturition and breeding in a low-density population with a near even sex ratio at the Savannah River Site (SRS), South Carolina. We conducted a series of intensive, 24-h radio-tracking periods of 13 females during spring and fall 2002. We compared daily range (ha), rate of travel (m/h), and distance between extreme daily locations (m), among the periods of pre-parturition and post-parturition and pre-, peak-, and post-rut. From pre-parturition to post-parturition, we observed decreases in diel range size (–38.2%), distance between extreme diel locations (–17.0%), and diel rate of travel (–18.2%). Diel range size, distance between extreme diel locations, and diel rate of travel during the pre-rut and rut exceeded those observed during post-rut. We further identified substantial increases in mobility during 12 24-h diel periods for eight females during our fall monitoring. Our data suggest that female white-tailed deer reduce mobility post-fawning following exaggerated movements during pre-parturition. Furthermore, despite a near equal sex ratio, estrous does may be required to actively seek potential mates due to low population density.

Male red ornamentation is associated with female red sensitivity in sticklebacks.

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Ingolf P Rick

Full Text Available Sexual selection theory proposes correlated evolutionary changes in mating preferences and secondary sexual characters based on a positive genetic correlation between preference and the preferred trait. Empirical work has provided support for a genetic covariation between female preference and male attractiveness in several taxa. Here, we study parent and offspring visual traits in threespine sticklebacks, Gasterosteus aculeatus. While focusing on the proximate basis of mating preferences, we compare the red breeding coloration of males, which strongly contributes to female choice, with their daughters' red sensitivity measured by optomotor response thresholds. We show that the red color expression of fathers correlates well with their daughters' red sensitivity. Given that a within-population genetic correlation between signal and preference was experimentally confirmed for the red coloration in sticklebacks, our results indicate a proximate mechanism in terms of perceptual sensitivity being involved in the co-evolution of female preferences and male mating signals.

Sex-Specific Habitat Utilization and Differential Breeding Investments in Christmas Island Frigatebirds throughout the Breeding Cycle.

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Janos C Hennicke

Full Text Available In seabirds, equal bi-parental care is the rule, as it is considered crucial for raising chicks successfully because seabirds forage in an environment with unpredictable and highly variable food supply. Frigatebirds forage in poor tropical waters, yet males reduce and even stop parental care soon after chick brooding, leaving the female to provision the chick alone for an extended fledging period. Using bird-borne tracking devices, male and female Christmas Island Frigatebirds (Fregata andrewsi were investigated during the brooding, late chick rearing and post-fledging period to examine whether sexes exhibit foraging strategies that may be linked to differential breeding investments. During brooding, males and females showed similar foraging behaviour under average marine productivity of oceanic waters close to the colony, but males shifted to more distant and more productive habitats when conditions deteriorated to continue with reduced chick provisioning. During the late chick rearing period, females progressively increased their foraging range to the more distant but productive marine areas that only males had visited during brooding. Birds spent the non-breeding period roosting in highly productive waters of the Sunda Shelf. The sex-specific utilisation of three different foraging habitats with different primary productivity (oceanic, coastal, and shelf areas allowed for temporal and spatial segregation in the exploitation of favourable habitats which seems to enable each sex to optimise its foraging profitability. In addition, post-fledging foraging movements of females suggest a biennial breeding cycle, while limited information on males suggests the possibility of an annual breeding cycle.

An International Comparison of Female and Male Students' Attitudes to the Use of Animals

Science.gov (United States)

Phillips, Clive; Izmirli, Serdar; Aldavood, Javid; Alonso, Marta; Choe, Bi; Hanlon, Alison; Handziska, Anastasija; Illmann, Gudrun; Keeling, Linda; Kennedy, Mark; Lee, Gwi; Lund, Vonne; Mejdell, Cecilie; Pelagic, Veselinas; Rehn, Therese

2011-01-01

Simple Summary We surveyed university students in 11 Eurasian countries for their attitudes to animals, using an internet-based questionnaire to which 1,902 female and 1,530 male student responded from 102 universities. Across countries female students had greater concern for animal welfare and rights than males, but especially so in more gender empowered countries. One contributing factor appeared to be the greater association of females than males with pets, and a possible outcome was greater female avoidance of meat consumption, especially red meat. Abstract Previous research has demonstrated that in households where the male partner is more dominant, there is convergence in male and female attitudes towards animals, whereas if the female partner is empowered they exhibit greater empathy towards animals than the male partner. We tested this theory of ‘female empowered empathy’ internationally in a survey of female and male students' attitudes towards use of animals, conducted in 11 Eurasian countries: China, Czech Republic, Great Britain, Iran, Ireland, South Korea, Macedonia, Norway, Serbia, Spain and Sweden. Gender empowerment was estimated for each country using the Gender Empowerment Measure designed by the United Nations. The survey was administered via the internet in universities within countries, and 1,902 female and 1,530 male student responses from 102 universities were received. Respondents rated the acceptability of 43 major concerns about human use of animals, and the importance of 13 world social issues, including animal protection, environmental protection and sustainable development. Females had greater concern for animal welfare and rights than males. There was a positive correlation between the Gender Empowerment Measure and the ratio of female to male concern for animal welfare and rights, but not for other world issues. Thus in countries where females were more empowered, principally Sweden, Norway and Great Britain, females had much

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

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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

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

Baseline and stress-induced levels of corticosterone in male and female Afrotropical and European temperate stonechats during breeding.

Science.gov (United States)

Apfelbeck, Beate; Helm, Barbara; Illera, Juan Carlos; Mortega, Kim G; Smiddy, Patrick; Evans, Neil P

2017-05-22

Latitudinal variation in avian life histories falls along a slow-fast pace of life continuum: tropical species produce small clutches, but have a high survival probability, while in temperate species the opposite pattern is found. This study investigated whether differential investment into reproduction and survival of tropical and temperate species is paralleled by differences in the secretion of the vertebrate hormone corticosterone (CORT). Depending on circulating concentrations, CORT can both act as a metabolic (low to medium levels) and a stress hormone (high levels) and, thereby, influence reproductive decisions. Baseline and stress-induced CORT was measured across sequential stages of the breeding season in males and females of closely related taxa of stonechats (Saxicola spp) from a wide distribution area. We compared stonechats from 13 sites, representing Canary Islands, European temperate and East African tropical areas. Stonechats are highly seasonal breeders at all these sites, but vary between tropical and temperate regions with regard to reproductive investment and presumably also survival. In accordance with life-history theory, during parental stages, post-capture (baseline) CORT was overall lower in tropical than in temperate stonechats. However, during mating stages, tropical males had elevated post-capture (baseline) CORT concentrations, which did not differ from those of temperate males. Female and male mates of a pair showed correlated levels of post-capture CORT when sampled after simulated territorial intrusions. In contrast to the hypothesis that species with low reproduction and high annual survival should be more risk-sensitive, tropical stonechats had lower stress-induced CORT concentrations than temperate stonechats. We also found relatively high post-capture (baseline) and stress-induced CORT concentrations, in slow-paced Canary Islands stonechats. Our data support and refine the view that baseline CORT facilitates energetically

Evidence That the Microbiota Counteracts Male Outbreeding Strategy by Inhibiting Sexual Signaling in Females

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Chloe Heys

2018-03-01

Full Text Available The microbiota is increasingly being recognized as having important impacts on many host biological processes. However, evidence of its effects on animal communication and breeding strategy is lacking. In this three-factorial study, we show that females were more willing to mate with related males, with relatedness likely being assessed through the microbiota. By contrast, male mating investment is concurrently determined by both the relatedness and microbiota status of the female. When the microbiota in female Drosophila melanogaster is altered by an antibiotic, male investment in sperm number increased when mating with unrelated females compared to related ones. Contrastingly, the presence of an intact microbiota in females canceled this male outbreeding strategy. As a consequence, the microbiota, when intact, decreased the fitness of the mating couple. Furthermore, we showed that female sexual signaling (cuticular hydrocarbons, with regards to kin recognition, significantly interacts with microbiota. Interestingly, the interaction is significant for hydrocarbons expressed by both sexes, but not for female-specific compounds. Taken together, our results suggest that microbiota can influence kin recognition by disfavoring male outbreeding strategies, likely by inhibiting key olfactory sexual signaling. This represents the first evidence of a host outbreeding strategy counteracted by their microbiota.

Don't get the blues: conspicuous nuptial colouration of male moor frogs (Rana arvalis) supports visual mate recognition during scramble competition in large breeding aggregations.

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Sztatecsny, Marc; Preininger, Doris; Freudmann, Anita; Loretto, Matthias-Claudio; Maier, Franziska; Hödl, Walter

2012-12-01

Conspicuous male colouration is expected to have evolved primarily through selection by female choice. In what way conspicuous colours could be advantageous to males scrambling for mates remains largely unknown. The moor frog (Rana arvalis) belongs to the so-called explosive breeders in which spawning period is short; intrasexual competition is strong, and males actively search and scramble for females. During breeding, male body colouration changes from a dull brown (similar to females) to a conspicuous blue, and we wanted to test if male blueness influences mating success or facilitates male mate recognition. To do so, we first measured the colour of mated and non-mated males using a spectrophotometer. In an experiment, we then analysed interactions of actual male moor frogs in natural spawning aggregations with a brown (resembling a female or a non-breeding male) and a blue model frog. Mated and non-mated males did not differ in colouration, suggesting that female choice based on colour traits was unlikely. In our behavioural experiment, male moor frogs spent significantly more time in contact and in amplexus with the brown model than with the blue model. Our results suggest that the nuptial colouration in moor frogs can act as a new type of visual signal in anurans evolved to promote instantaneous mate recognition allowing males to quickly move between rivals while scrambling for females. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00265-012-1412-6) contains supplementary material, which is available to authorized users.

Serum levels at moment of breeding of triiodothyronine (T3), thyroxine (T4), and progesterone in Saanen goats females during normal and induced heat and testosterone in 12 Saanen goats males

International Nuclear Information System (INIS)

Prestes, Nereu C.; Vulcano, Luiz C.; Mamprim, Maria J.; Oba, Eunice

1996-01-01

The aim of this experiment was to measure the level of triiodothyronine(T 3 ), thyroxine(T 4 ) and progesterone in the serum of females Saanen goats. The progesterone levels were: 0.59 and 0.79 ng/μl considering breeding during normal and induced heat respectively. The T 3 values were: 192.8 and 251.32 ng/dl while T 4 values were: 36.38 and 31.68 ng/dl in the same condition above. The average testosterone level at the moment of breeding in the serum of 12 males was 1.38 pg/ml. (author)

Prevalence of congenital heart disease in 76,301 mixed-breed dogs and 57,025 mixed-breed cats.

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Schrope, Donald P

2015-09-01

Assess the prevalence of congenital heart disease (CHD) in a large population of mixed-breed dogs and cats. 76,301 mixed-breed dogs and 57,025 mixed-breed cats. Retrospective review of records and examinations based on specified diagnostic criteria. Among mixed-breed dogs, the prevalence of CHD was 0.13% (51.4% female) and of innocent murmurs was 0.10% (53.0% male). Pulmonic stenosis was the most common defect followed by patent ductus arteriosus, aortic stenosis, and ventricular septal defect. Among mixed-breed cats, prevalence of CHD was 0.14% (55.2% male) and of innocent murmurs was 0.16% (54.4% male). When the 25 cats with dynamic left or right ventricular outflow obstruction were counted with cases of innocent murmurs, the overall prevalence was 0.2%. Ventricular septal defects were the most common feline CHD followed closely by aortic stenosis and hypertrophic obstructive cardiomyopathy. There was no overall sex predilection for CHD in mixed-breed cats or dogs, and no significant difference in CHD prevalence between cats or dogs. Among dogs, subvalvular aortic stenosis and mitral valve dysplasia had a male predisposition while patent ductus arteriosus had a female predisposition. Among cats, valvular pulmonic stenosis, subvalvular and valvular aortic stenosis, and ventricular septal defects had a male predisposition while pulmonary artery stenosis had a female predisposition. The prevalence of CHD in a mixed-breed dogs and cats is lower than for prior studies, perhaps due to the lack of purebreds in the study population or actual changes in disease prevalence. Copyright © 2015 Elsevier B.V. All rights reserved.

Den site activity patterns of adult male and female swift foxes, Vulpes velox, in Northwestern Texas

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Lemons, P.R.; Ballard, W.B.; Sullivan, R.M.; Sovada, M.A.

2003-01-01

Activity of Swift Foxes (Vulpes velox) at den sites was studied in northwestern Texas during pup rearing seasons in 2000 and 2001 to determine role of males in parental care. Twenty-four percent of radio-collared females with a potential to breed successfully raised pups to eight weeks of age. We intensively monitored presence and absence of male and female Swift Foxes at two den sites each year. Females were present >2.6 times more at den sites than males during the pup rearing season. Female and male Swift Foxes largely stayed at dens during diurnal hours and were active away from dens during nocturnal and crepuscular hours. Females and males spent 12.4% and 3.0% more time at dens before pups emerged, than after pups emerged, respectively. Following depredation of one male parent, the female spent 29% less time at the den site. Decrease in time spent at the den by the female following loss of her mate suggested that loss of one parent might severely impact recruitment of Swift Foxes. Our observations indicated that intense Coyote (Canis latrans) depredation may severely impact pup-rearing success as well as the parental care within Swift Fox family groups.

Balancing in- and out-breeding by the predatory mite Phytoseiulus persimilis.

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Atalay, Demet; Schausberger, Peter

2018-02-01

In- and out-breeding depressions are commonly observed phenomena in sexually reproducing organisms with a patchy distribution pattern, and spatial segmentation and/or isolation of groups. At the genetic level, inbreeding depression is due to increased homozygosity, whereas outbreeding depression is due to inferior genetic compatibility of mates. Optimal outbreeding theory suggests that intermediate levels of mate relatedness should provide for the highest fitness gains. Here, we assessed the fitness consequences of genetic relatedness between mates in plant-inhabiting predatory mites Phytoseiulus persimilis, which are obligatory sexually reproducing but haplo-diploid. Both females and males arise from fertilized eggs but males lose the paternal chromosome set during embryogenesis, dubbed pseudo-arrhenotoky. Phytoseiulus persimilis are highly efficacious in reducing crop-damaging spider mite populations and widely used in biological control. Using iso-female lines of two populations, from Sicily and Greece, we assessed the fecundity of females, and sex ratio of their offspring, that mated with either a sibling, a male from the same population or a male from the other population. Additionally, we recorded mating latency and duration. Females mating with a male from the same population produced more eggs, with a lower female bias, over a longer time than females mating with a sibling or with a male from the other population. Mating latency was unaffected by mate relatedness; mating duration was disproportionally long in sibling couples, likely indicating female reluctance to mate and sub-optimal spermatophore transfer. Our study provides a rare example of in- and out-breeding depression in a haplo-diploid arthropod, supporting the optimal outbreeding theory.

Cortical activation during mental rotation in male-to-female and female-to-male transsexuals under hormonal treatment.

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Carrillo, Beatriz; Gómez-Gil, Esther; Rametti, Giuseppina; Junque, Carme; Gomez, Angel; Karadi, Kazmer; Segovia, Santiago; Guillamon, Antonio

2010-09-01

There is strong evidence of sex differences in mental rotation tasks. Transsexualism is an extreme gender identity disorder in which individuals seek cross-gender treatment to change their sex. The aim of our study was to investigate if male-to-female (MF) and female-to-male (FM) transsexuals receiving cross-sex hormonal treatment have different patterns of cortical activation during a three-dimensional (3D) mental rotation task. An fMRI study was performed using a 3-T scan in a sample of 18 MF and 19 FM under chronic cross-sex hormonal treatment. Twenty-three males and 19 females served as controls. The general pattern of cerebral activation seen while visualizing the rotated and non-rotated figures was similar for all four groups showing strong occipito-parieto-frontal brain activation. However, compared to control males, the activation of MF transsexuals during the task was lower in the superior parietal lobe. Compared to control females, MF transsexuals showed higher activation in orbital and right dorsolateral prefrontal regions and lower activation in the left prefrontal gyrus. FM transsexuals did not differ from either the MF transsexual or control groups. Regression analyses between cerebral activation and the number of months of hormonal treatment showed a significant negative correlation in parietal, occipital and temporal regions in the MF transsexuals. No significant correlations with time were seen in the FM transsexuals. In conclusion, although we did not find a specific pattern of cerebral activation in the FM transsexuals, we have identified a specific pattern of cerebral activation during a mental 3D rotation task in MF transsexuals under cross-sex hormonal treatment that differed from control males in the parietal region and from control females in the orbital prefrontal region. The hypoactivation in MF transsexuals in the parietal region could be due to the hormonal treatment or could reflect a priori cerebral differences between MF transsexual

Male depression in females?

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Möller-Leimkühler, Anne Maria; Yücel, Mete

2010-02-01

Scientific evidence for a male-typed depression ("male depression") is still limited, but mainly supports this concept with respect to single externalizing symptoms or symptom clusters. In particular, studies on non-clinical populations including males and females are lacking. The present study aims at assessing general well-being, the risk and the symptoms of male depression dependent on biological sex and gender-role orientation on instrumental (masculine) and expressive (feminine) personality traits in an unselected community sample of males and females. Students (518 males, 500 females) of the Ludwig-Maximilians-University of Munich, Germany, were asked to participate in a "stress study" and complete the following self-report questionnaires: the WHO-5 Well-being Index [Bech, P., 1998. Quality of Life in the Psychiatric Patient. Mosby-Wolfe, London], the Gotland Scale for Male Depression [Walinder, J., Rutz, W., 2001. Male depression and suicide. International Clinical Psychopharmacology 16 (suppl 2), 21-24] and the German Extended Personal Attribute Questionnaire [Runge, T.E., Frey, D., Gollwitzer, P.M., et al., 1981. Masculine (instrumental) and feminine (expressive) traits. A comparison between students in the United States and West Germany. Journal of Cross-Cultural Psychology 12, 142-162]. General well-being of the students was significantly lower compared to population norms. Contrary to expectations, female students had a greater risk of male depression than male students (28.9% vs. 22.4%; p<0.05). Overall, prototypic depressive symptoms as well as externalizing symptoms were more pronounced in females. In the subgroup of those at risk for male depression, biological sex and kind of symptoms were unrelated. Principal component analyses revealed a similar symptom structure for males and females. Low scores on masculinity/instrumentality significantly predicted higher risk of male depression, independent of biological sex. The study sample is not

Tracking males and females: investigating protandry throughout the annual cycle in a small migratory songbird

DEFF Research Database (Denmark)

Pedersen, Lykke; Tøttrup, Anders P.; Thorup, Kasper

Protandry, the phenomenon of males arriving earlier at the breeding grounds than females, has been demonstrated in several migratory bird species. The pattern is linked to reproductive success and often ascribed to selection for securing the highest quality territories or mates. Protandry can...

Male sexual harassment alters female social behaviour towards other females.

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Darden, Safi K; Watts, Lauren

2012-04-23

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

Subordinate females in the cooperatively breeding Seychelles warbler obtain direct benefits by joining unrelated groups.

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Groenewoud, Frank; Kingma, Sjouke A; Hammers, Martijn; Dugdale, Hannah L; Burke, Terry; Richardson, David S; Komdeur, Jan

2018-05-11

-breeders, obtaining maternity in the new territory, and were likely to inherit the territory in the future, leading to higher lifetime reproductive success compared to females that floated. Males never reproduced as subordinates, which may be one explanation why subordinate between-group dispersal by males is rare. 6.Our results suggest that subordinate between-group dispersal is used by females to obtain reproductive benefits when options to disperse to an independent breeding position are limited. This provides important insight into the additional strategies that individuals can use to obtain reproductive benefits. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Dynamic endocrine responses to stress: evidence for energetic constraints and status dependence in breeding male green turtles.

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Jessop, Tim S; Knapp, Rosemary; Whittier, Joan M; Limpus, Col J

2002-03-01

During reproduction, male vertebrates may exhibit a continuum of interactions between sex and adrenal steroids during stressful events, the outcome of which may be important in either reducing or promoting male reproductive success. We studied adult male green turtles (Chelonia mydas) to examine if they altered plasma corticosterone (CORT) and androgen levels in response to a standardized capture/restraint stressor as potential mechanisms to maintain reproductive activity during stressful events. At the population level, we found that migrant breeding males had a significantly smaller CORT response to the capture/restraint stressor compared to nonbreeding males and that this decreased response coincided with the generally poorer body condition of migrant breeders. In contrast, plasma androgen levels decreased significantly in response to the capture/restraint stressor in migrant breeding males, but not in nonbreeding and pre-migrant breeding males. For individual migrant breeding males, the magnitude of their CORT and androgen responses to the capture/restraint stressor was highly correlated with their body condition and body length, respectively. Our results demonstrate that male green turtles exhibit complex interactions in their endocrine responses to a capture/restraint stressor and that variation in these interactions is associated with differences in males' reproductive, energetic, and physical state. We hypothesize that interplay between physical status and plasma hormone responses to stressors could have important consequences for male green turtle reproduction.

Female choice impacts residential male takeover in golden snub-nosed monkeys (Rhinopithecus roxellana).

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Fang, Gu; Chen, Jing; Pan, Ru-Liang; Qi, Xiao-Guang; Li, Bao-Guo

2018-07-18

In primate species with social systems consisting of one-male breeding units (OMUs), resident male takeover represents a major challenge to individual reproductive success and mating strategies. The golden snub-nosed monkey (Rhinopithecus roxellana) is characterized by large multilevel societies (MLS) comprised of several OMUs and all-male units (AMUs); however, the factors and mechanisms associated with resident male takeover, which offer important insight into primate reproduction and social strategies, are still poorly understood. Based on 5-year monitoring data from a free-ranging herd of golden monkeys from the Qinling Mountains in China, we categorized three phases of an OMU, that is, a rising phase, developing phase, and declining phase. The rising and declining phases were unstable periods in which male takeover in an OMU might occur. Factors causing takeover, such as leader male rank, fighting ability, reproduction rate, and affiliation (proximity, allogrooming), were analyzed for males and females and for different OMUs. Results indicated that the new resident male's fighting ability was lower than that of the former resident male in 23 cases. After replacement, the rank order of the new resident male significantly declined. Females involved in a takeover increased their distance from the resident male and decreased mating frequency during the three months prior to takeover. Females with infants under one-year-old had a marked effect on the specific time of takeover occurrence. These results suggested that female choice was the main factor deciding whether a takeover attempt was successful. Furthermore, rather than male conflict, females more often initiated and affected takeover and outcome, implying that the social status and competitive ability of the males played lesser roles during takeover.

Sexual harassment and female gregariousness in the South American sea lion, Otaria flavescens

Science.gov (United States)

Cappozzo, Humberto L.; Túnez, Juan I.; Cassini, Marcelo H.

2008-07-01

Most colonial pinnipeds form extreme clusters of breeding females that cannot be entirely explained by the distribution of sites for reproduction. Avoidance of male harassment has been postulated as an important determinant of reproductive aggregation in this group of mammals. Female gregariousness can reduce harassment by resident males by two mechanisms; directly by the ‘dilution effect’ or indirectly because resident males that defend large female groups are less harassing. In order to investigate the relationship between male harassment and female gregariousness in relation to the size of breeding groups, we analysed the behaviour of dominant males and their females in a breeding colony of Otaria flavescens. Females in large breeding groups received less harassment by resident males due to dilution effects and because males that defended a large group interacted less frequently with females than males with small groups.

Impact of mimicking natural dispersion on breeding success of captive North American Cheetahs (Acinonyx jubatus).

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Gillman, Sierra J; Ziegler-Meeks, Karen; Eager, Carol; Tenhundfeld, Thomas A; Shaffstall, Wendy; Stearns, Mary Jo; Crosier, Adrienne E

2017-09-01

This paper examines the effects of transfer away from natal facility and littermate presence on cheetah breeding success in the AZA Species Survival Plan (SSP) population. Transfer and breeding history data for captive males and females were gathered from seven and four AZA SSP breeding facilities, respectively, to identify factors influencing breeding success. The results indicate that transfer history (p = 0.032), age at transfer (p = 0.013), and female littermate presence/absence (p = 0.04) was associated with breeding success, with females transferred away from their natal facility before sexual maturity and without littermates present accounting for the highest breeding success. Keeping males at their natal facility and/or removing them from their coalitions did not negatively affect their breeding success. Males appeared to demonstrate the same fecundity regardless of transfer history or coalition status, indicating that dispersal away from natal environment was not as critical for the breeding success of males compared with female cheetahs. These results highlight the significance of moving females away from their natal environment, as would occur in the wild, and separating them from their female littermates for optimization of breeding success in the ex situ population. © 2017 Wiley Periodicals, Inc.

Is higher risk sex common among male or female youths?

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Berhan, Yifru; Berhan, Asres

2015-01-01

There are several studies that showed the high prevalence of high-risk sexual behaviors among youths, but little is known how significant the proportion of higher risk sex is when the male and female youths are compared. A meta-analysis was done using 26 countries' Demographic and Health Survey data from and outside Africa to make comparisons of higher risk sex among the most vulnerable group of male and female youths. Random effects analytic model was applied and the pooled odds ratios were determined using Mantel-Haenszel statistical method. In this meta-analysis, 19,148 male and 65,094 female youths who reported to have sexual intercourse in a 12-month period were included. The overall OR demonstrated that higher risk sex was ten times more prevalent in male youths than in female youths. The practice of higher risk sex by male youths aged 15-19 years was more than 27-fold higher than that of their female counterparts. Similarly, male youths in urban areas, belonged to a family with middle to highest wealth index, and educated to secondary and above were more than ninefold, eightfold and sixfold at risk of practicing higher risk sex than their female counterparts, respectively. In conclusion, this meta-analysis demonstrated that the practice of risky sexual intercourse by male youths was incomparably higher than female youths. Future risky sex protective interventions should be tailored to secondary and above educated male youths in urban areas.

Recurrent population improvement of rice breeding facilitated with male sterility

International Nuclear Information System (INIS)

Fujimaki, Hiroshi

1982-01-01

A new rice breeding system has been developed, making use of genic male sterility to utilize diverse breeding materials and to promote genetic recombination. In this system, recurrent selection technique and introgressive hybridization were used to increase the frequencies of producing desired genotypes and to improve the population in succession. To promote genetic recombination by the recurrent selection technique, intermating within the population is necessary, and to introduce useful germ plasms by the introgressive hybridization, back crossing with new genetic material is necessary. These can be done efficiently by using the recessive alleles for male sterility, and the representative models for thisF type of breeding were presented. (Kaihara, S.)

Can persistence hunting signal male quality? A test considering digit ratio in endurance athletes.

Directory of Open Access Journals (Sweden)

Daniel Longman

Full Text Available Various theories have been posed to explain the fitness payoffs of hunting success among hunter-gatherers. 'Having' theories refer to the acquisition of resources, and include the direct provisioning hypothesis. In contrast, 'getting' theories concern the signalling of male resourcefulness and other desirable traits, such as athleticism and intelligence, via hunting prowess. We investigated the association between androgenisation and endurance running ability as a potential signalling mechanism, whereby running prowess, vital for persistence hunting, might be used as a reliable signal of male reproductive fitness by females. Digit ratio (2D:4D was used as a proxy for prenatal androgenisation in 439 males and 103 females, while a half marathon race (21km, representing a distance/duration comparable with that of persistence hunting, was used to assess running ability. Digit ratio was significantly and positively correlated with half-marathon time in males (right hand: r = 0.45, p<0.001; left hand: r = 0.42, p<0.001 and females (right hand: r = 0.26, p<0.01; left hand: r = 0.23, p = 0.02. Sex-interaction analysis showed that this correlation was significantly stronger in males than females, suggesting that androgenisation may have experienced stronger selective pressure from endurance running in males. As digit ratio has previously been shown to predict reproductive success, our results are consistent with the hypothesis that endurance running ability may signal reproductive potential in males, through its association with prenatal androgen exposure. However, further work is required to establish whether and how females respond to this signalling for fitness.

Specific cerebral activation due to visual erotic stimuli in male-to-female transsexuals compared with male and female controls: an fMRI study.

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Gizewski, Elke R; Krause, Eva; Schlamann, Marc; Happich, Friederike; Ladd, Mark E; Forsting, Michael; Senf, Wolfgang

2009-02-01

Transsexuals harbor the strong feeling of having been born to the wrong sex. There is a continuing controversial discussion of whether or not transsexualism has a biological representation. Differences between males and females in terms of functional imaging during erotic stimuli have been previously described, revealing gender-specific results. Therefore, we postulated that male-to-female (MTF) transsexuals may show specific cerebral activation differing from their biological gender. Cerebral activation patterns during viewing of erotic film excerpts in functional magnetic resonance imaging (fMRI). Twelve male and 12 female heterosexual volunteers and 12 MTF transsexuals before any treatment viewed erotic film excerpts during fMRI. Additionally, subjective rating of sexual arousal was assessed. Statistics were performed using the Statistical Parametric Mapping software. Significantly enhanced activation for men compared with women was revealed in brain areas involved in erotic processing, i.e., the thalamus, the amygdala, and the orbitofrontal and insular cortex, whereas no specific activation for women was found. When comparing MTF transsexuals with male volunteers, activation patterns similar to female volunteers being compared with male volunteers were revealed. Sexual arousal was assessed using standard rating scales and did not differ significantly for the three groups. We revealed a cerebral activation pattern in MTF transsexuals compared with male controls similar to female controls compared with male controls during viewing of erotic stimuli, indicating a tendency of female-like cerebral processing in transsexualism.

Female burying beetles benefit from male desertion: sexual conflict and counter-adaptation over parental investment.

Directory of Open Access Journals (Sweden)

Giuseppe Boncoraglio

Full Text Available Sexual conflict drives the coevolution of sexually antagonistic traits, such that an adaptation in one sex selects an opposing coevolutionary response from the other. Although many adaptations and counteradaptations have been identified in sexual conflict over mating interactions, few are known for sexual conflict over parental investment. Here we investigate a possible coevolutionary sequence triggered by mate desertion in the burying beetle Nicrophorus vespilloides, where males commonly leave before their offspring reach independence. Rather than suffer fitness costs as a consequence, our data suggest that females rely on the male's absence to recoup some of the costs of larval care, presumably because they are then free to feed themselves on the carcass employed for breeding. Consequently, forcing males to stay until the larvae disperse reduces components of female fitness to a greater extent than caring for young singlehandedly. Therefore we suggest that females may have co-evolved to anticipate desertion by their partners so that they now benefit from the male's absence.

Female Burying Beetles Benefit from Male Desertion: Sexual Conflict and Counter-Adaptation over Parental Investment

Science.gov (United States)

Boncoraglio, Giuseppe; Kilner, Rebecca M.

2012-01-01

Sexual conflict drives the coevolution of sexually antagonistic traits, such that an adaptation in one sex selects an opposing coevolutionary response from the other. Although many adaptations and counteradaptations have been identified in sexual conflict over mating interactions, few are known for sexual conflict over parental investment. Here we investigate a possible coevolutionary sequence triggered by mate desertion in the burying beetle Nicrophorus vespilloides, where males commonly leave before their offspring reach independence. Rather than suffer fitness costs as a consequence, our data suggest that females rely on the male's absence to recoup some of the costs of larval care, presumably because they are then free to feed themselves on the carcass employed for breeding. Consequently, forcing males to stay until the larvae disperse reduces components of female fitness to a greater extent than caring for young singlehandedly. Therefore we suggest that females may have co-evolved to anticipate desertion by their partners so that they now benefit from the male's absence. PMID:22355390

Domestic chickens defy Rensch's rule: sexual size dimorphism in chicken breeds.

Science.gov (United States)

Remeš, V; Székely, T

2010-12-01

Sexual size dimorphism (SSD), i.e. the difference in sizes of males and females, is a key evolutionary feature that is related to ecology, behaviour and life histories of organisms. Although the basic patterns of SSD are well documented for several major taxa, the processes generating SSD are poorly understood. Domesticated animals offer excellent opportunities for testing predictions of functional explanations of SSD theory because domestic stocks were often selected by humans for particular desirable traits. Here, we analyse SSD in 139 breeds of domestic chickens Gallus gallus domesticus and compare them to their wild relatives (pheasants, partridges and grouse; Phasianidae, 53 species). SSD was male-biased in all chicken breeds, because males were 21.5 ± 0.55% (mean ± SE) heavier than females. The extent of SSD did not differ among breed categories (cock fighting, ornamental and breeds selected for egg and meat production). SSD of chicken breeds was not different from wild pheasants and allies (23.5 ± 3.43%), although the wild ancestor of chickens, the red jungle fowl G. gallus, had more extreme SSD (male 68.8% heavier) than any domesticated breed. Male mass and female mass exhibited positive allometry among pheasants and allies, consistently with the Rensch's rule reported from various taxa. However, body mass scaled isometrically across chicken breeds. The latter results suggest that sex-specific selection on males vs. females is necessary to generate positive allometry, i.e. the Rensch's rule, in wild populations. © 2010 The Authors. Journal Compilation © 2010 European Society For Evolutionary Biology.

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

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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.

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.

Mating competitiveness of irradiated males and females of the indian meal moth (Lepidoptera: Pyralidae)

International Nuclear Information System (INIS)

Brower, J.H.

1978-01-01

One-day-old adults of the Indian meal moth, Plodia interpunctella (Huebner), were irradiated (I) with either 35 krad (a partially sterilizing dose) or 50 krad (a sterilizing dose) and combined with untreated (U) adults at numbers of 1, 5, 10, 15, or 25 treated males or females per pair of untreated adults. At 25 males per pair, egg hatch was reduced to 4.8 and 22.2% at 35 and 50 krad, respectively. The calculated degree of competitiveness showed that both males and females were more competitive after treatment with 35 krad than after treatment with 50 krad and that treated females were more competitive (based on percentage egg hatch) at both doses than corresponding males. Irradiated females were fully competitive at most release ratios, but I males were not fully competitive even at the higher release ratios, although the decreases were not large enough to seriously affect their use for field control. (author)

Differentiating the evolution of female song and male-female duets in the New World blackbirds: can tropical natural history traits explain duet evolution?

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Odom, Karan J; Omland, Kevin E; Price, J Jordan

2015-03-01

Female bird song and combined vocal duets of mated pairs are both frequently associated with tropical, monogamous, sedentary natural histories. Little is known, however, about what selects for duetting behavior versus female song. Female song likely preceded duet evolution and could drive apparent relationships between duets and these natural histories. We compared the evolution of female song and male-female duets in the New World blackbirds (Icteridae) by investigating patterns of gains and losses of both traits and their relationships with breeding latitude, mating system, nesting pattern, and migratory behavior. We found that duets evolved only in lineages in which female song was likely ancestral. Both female song and duets were correlated with tropical breeding, social monogamy, territorial nesting, and sedentary behavior when all taxa were included; however, correlations between duets and these natural history traits disappeared when comparisons were limited to taxa with female song. Also, likelihood values supported stronger relationships between the natural history traits and female song than between these traits and duets. Our results suggest that the natural histories thought to favor the evolution of duetting may in fact be associated with female song and that additional selection pressures are responsible for the evolution of duets. © 2015 The Author(s).

A Nightmare for Males? A Maternally Transmitted Male-Killing Bacterium and Strong Female Bias in a Green Lacewing Population.

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Masayuki Hayashi

Full Text Available For maternally transmitted microbes, a female-biased host sex ratio is of reproductive advantage. Here we found a strong female bias in a field population of the green lacewing, Mallada desjardinsi (Insecta; Neuroptera. This bias was attributed to the predominance of individuals harboring a maternally inherited male-killing bacterium that was phylogenetically closely related to the plant-pathogenic Spiroplasma phoeniceum and Spiroplasma kunkelii. Among 35 laboratory-reared broods produced by wild-caught females, 21 broods (60%-all infected with Spiroplasma-consisted of only females (940 individuals. Among 14 broods consisting of both males and females (516 and 635 individuals, respectively, 4 broods were doubly infected with Spiroplasma and Rickettsia, 6 broods were singly infected with Rickettsia, and 3 broods were uninfected (remaining one brood was unknown. Mortality during embryonic and larval development was prominent in all-female broods but not in normal sex ratio broods. Following antibiotic treatment on all-female broods, mortality was significantly reduced and the sex ratio was restored to 1:1. Strong expression and high prevalence of this male-killer is remarkable considering its low density (~10-5-10-4 cells per host mitochondrial gene copy based on quantitative PCR. In addition, a bacterium closely related to Rickettsia bellii was present in 25 of 34 broods (73.5%, irrespective of the sex ratio, with the infection density comparable to other cases of endosymbiosis (~10-2-10-1 cells per mitochondrial gene copy. Higher density of Rickettsia than Spiroplasma was also demonstrated by electron microscopy which visualized both Spiroplasma-like cells and Rickettsia-like cells inside and outside the ovarian cells.

Hormonal regulation of steroid receptor coactivator-1 mRNA in the male and female green anole brain.

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Kerver, H N; Wade, J

2015-03-01

Green anole lizards are seasonal breeders, with male sexual behaviour primarily regulated by an annual increase in testosterone. Morphological, biochemical and behavioural changes associated with reproduction are activated by testosterone, generally with a greater effect in the breeding season (BS) than in the nonbreeding season (NBS). The present study investigates the possibility that differences in a steroid receptor coactivator may regulate this seasonal difference in responsiveness to testosterone. In situ hybridisation was used to examine the expression of steroid receptor coactivator-1 (SRC-1) in the brains of gonadally intact male and female green anoles across breeding states. A second experiment examined gonadectomised animals with and without testosterone treatment. Gonadally intact males had more SRC-1 expressing cells in the preoptic area and larger volumes of this region as defined by these cells than females. Main effects of both sex and season (males > females and BS > NBS) were present in cell number and volume of the ventromedial hypothalamus. An interaction between sex and season suggested that high expression in BS males was driving these effects. In hormone-manipulated animals, testosterone treatment increased both the number of SRC-1 expressing cells in and volumes of the preoptic area and amygdala. These results suggest that testosterone selectively regulates SRC-1, and that this coactivator may play a role in facilitating reproductive behaviours across both sexes. However, changes in SRC-1 expression are not likely responsible for the seasonal change in responsiveness to testosterone. © 2014 British Society for Neuroendocrinology.

The dyadic adjustment of female-to-male transsexuals.

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Fleming, M; MacGowan, B; Costos, D

1985-02-01

Dyadic adjustment, sexual activities, and marital stability in the relationships of female-to-male transsexuals and their spouses were examined. Participants were 22 female-to-male transsexuals who had undergone some form of surgery to alter their anatomical sex, their spouses, and a control group of married or cohabitating nontranssexual men and women. Participants were administered the Dyadic Adjustment Scale and additional items to assess quantitatively their marital relationships. The transsexuals and their spouses were also asked open-ended interview questions concerning marital and life adjustments. Generally, the transsexuals and their spouses reported good and mutually satisfying interpersonal relationships that are in many ways comparable to those of the matched control group. These findings lend support to the previous clinical interview studies that have reported that female-to-male transsexuals form stable and enduring intimate relationships.

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

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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.

Responses of female rock lizards to multiple scent marks of males: effects of male age, male density and scent over-marking.

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Martín, José; López, Pilar

2013-03-01

Scent-marked substrates may inform conspecifics on the characteristics of territorial males. Scent-marks of male Carpetan rock lizards (Iberolacerta cyreni) affect space use of females, which by selecting an area may increase the probability of mating with the male that has scent-marked that area. However, males do not hold exclusive territories, and scent-marks of different individual males are often together. This may provide complex information from multiple sources on the social structure. Here, we examined female preference in response to scent marks of various males and combinations in a laboratory experiment. Females preferred areas scent-marked by territorial old males against those scent-marked by young satellite-sneaker males. This reflected the known preference of females for mating with old males. In a second experiment, females preferred areas scent-marked by two males to areas of similar size marked by a single male. This may increase the probability of obtaining multiple copulations with different males, which may favour sperm competition and cryptic female choice, or may be a way to avoid infertile males. Finally, when we experimentally over-marked the scent-marks of an old male with scent-marks of a young male, females did not avoid, nor prefer, the over-marked area, suggesting that the quality of the old male may override the presence of a satellite male. We suggest that, irrespective of the causes underlying why a female selects a scent-marked area, this strategy may affect her reproductive success, which may have the same evolutionary consequences that "direct" mate choice decisions of other animals. Copyright © 2013 Elsevier B.V. All rights reserved.

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.

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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.

Adolescents' Contribution to Household Production: Male and Female Differences.

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Sanik, Margaret Mietus; Stafford, Kathryn

1985-01-01

Develops a model to predict the contribution adolescent males and females make to household work, based upon family characteristics, human capital of the adolescent, geographic location, and societal expectations. Adolescent females worked longer than males, regardless of birth order. Time use for household work was largely unaffected by family…

Adolescent Male-to-Female Transgender Voice and Communication Therapy

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Hancock, Adrienne; Helenius, Lauren

2012-01-01

Current research to describe and evaluate effectiveness of voice and communication therapy for male-to-female transgender people is limited to adults. This paper provides rationale, procedures, and outcomes from voice and communication therapy for a male-to-female transgender adolescent 15 years of age. Treatment addressed vocal hygiene, breath…

Female nurses' sensitivity to male genitalia-related care in mainland China.

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Zang, Yu-Li; Chung, Loretta Y F; Wong, Thomas K S; Chan, Moon Fai

2012-02-01

To discover the latent psychosocial construct of female nurses' sensitivity to male genitalia-related care in the context of sexual conservativeness. Many nursing activities involve direct exposure or contact with male external genitalia. In the sexually conservative culture and the predominance of female nurses, this area is the subject of continuing interest and investigation. Methodological research design. An item pool related to male genitalia-related care was generated through a panel of experts and then reduced to a short form questionnaire, the Female Nurses' Sensitivity to Male Genitalia Related Care scale. Using data from a purposive sample of 588 female nurses, the structure of the questionnaire was examined using structural equation modelling. The validity was examined against existing scales. The 13-item Female Nurses' Sensitivity to Male Genitalia Related Care scale has a two-factor structure with high internal consistency (α = 0·87) and test-retest reliability of 0·90. Nearly all model fit measures reach the criteria of being an acceptable model fit except chi-squared statistics. Scores on Female Nurses' Sensitivity to Male Genitalia Related Care can be best predicted by that of brief Fear of Negative Evaluation Scale, Embarrassability Scale and Situational Susceptibility to Embarrassment Scale. The anxiety of projecting a positive image and the pursuit of sexual propriety may underpin female nurses' sensitivity to male genitalia-related care. This trait can be measured by the 13-item female nurses' sensitivity-male genitalia-related care scale with satisfactory psychometric properties including internal consistency, reliability, content validity and construct validity. Particular attention shall be paid to the negative effects of social rules or norms including sexual propriety rules over (female) nurses' perceptions, attitudes and behaviours. Strengthening nursing education in this regard is important to overcome negative effects on female

Both male and female identity influence variation in male signalling effort

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Svensson P Andreas

2011-08-01

Full Text Available Abstract Background Male sexual displays play an important role in sexual selection by affecting reproductive success. However, for such displays to be useful for female mate choice, courtship should vary more among than within individual males. In this regard, a potentially important source of within male variation is adjustment of male courtship effort in response to female traits. Accordingly, we set out to dissect sources of variation in male courtship effort in a fish, the desert goby (Chlamydogobius eremius. We did so by designing an experiment that allowed simultaneous estimation of within and between male variation in courtship, while also assessing the importance of the males and females as sources of courtship variation. Results Although males adjusted their courtship depending on the identity of the female (a potentially important source of within-male variation, among-male differences were considerably greater. In addition, male courtship effort towards a pair of females was highly repeatable over a short time frame. Conclusion Despite the plasticity in male courtship effort, courtship displays had the potential to reliably convey information about the male to mate-searching females. Our experiment therefore underscores the importance of addressing the different sources contributing to variation in the expression of sexually-selected traits.

A structural comparison of female-male and female-female mounting in Japanese macaques (Macaca fuscata).

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Ottenheimer Carrier, Lydia; Leca, Jean-Baptiste; Pellis, Sergio; Vasey, Paul L

2015-10-01

In certain populations, female Japanese macaques (Macaca fuscata) mount both males and females. Vasey (2007) proposed that female-female sexual mounting in Japanese macaques may be a neutral evolutionary by-product of a purported adaptation, namely, female-male mounting. In this study, we aim to further examine the proposed link between female-male and female-female mounting in Japanese macaques by comparing the structural characteristics that define both forms of mounting. We do so using Eshkol-Wachman Movement Notation (EWMN), a globographic reference system that can be used to describe the position of body segments. No significant differences were observed in the female mounters' positioning of eight different body segments (i.e., lower torso, mid-torso, upper torso, upper arm, lower arm, upper leg, lower leg, and foot) during female-male and female-female mounting. This finding lends support to the conclusion that female-female and female-male mounting are structurally, and thus, evolutionarily, related. Copyright © 2015 Elsevier B.V. All rights reserved.

Natal and breeding philopatry of female Steller sea lions in southeastern Alaska.

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Kelly K Hastings

Full Text Available Information on drivers of dispersal is critical for wildlife conservation but is rare for long-lived marine mammal species with large geographic ranges. We fit multi-state mark-recapture models to resighting data of 369 known-aged Steller sea lion (Eumetopias jubatus females marked as pups on their natal rookeries in southeastern Alaska from 1994-2005 and monitored from 2001-15. We estimated probabilities of females being first observed parous at their natal site (natal philopatry, and of not moving breeding sites among years (breeding philopatry at large (> 400 km, all five rookeries in southeastern Alaska and small (< 4 km, all islands within the largest rookery, Forrester Island Complex, F spatial scales. At the rookery scale, natal philopatry was moderately high (0.776-0.859 for most rookeries and breeding philopatry was nearly 1, with < 3% of females switching breeding rookeries between years. At more populous islands at F, natal philopatry was 0.500-0.684 versus 0.295-0.437 at less populous islands, and breeding philopatry was 0.919-0.926 versus 0.604-0.858. At both spatial scales, the probability of pupping at a non-natal site increased with population size of, and declined with distance from, the destination site. Natal philopatry of < 1 would increase gene flow, improve population resilience, and promote population recovery after decline in a heterogeneous environment. Very high breeding philopatry suggests that familiarity with neighboring females and knowledge of the breeding site (the topography of pupping sites and nearby foraging locations may be a critical component to reproductive strategies of sea lions.

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

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Célia Bordier

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

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

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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.

Cricothyroid approximation and subluxation in 21 male-to-female transsexuals

NARCIS (Netherlands)

Kanagalingam, Jeeve; Georgalas, Christos; Wood, Gary R.; Ahluwalia, Suki; Sandhu, Guri; Cheesman, Anthony D.

2005-01-01

OBJECTIVES: To evaluate the medium-term outcome of cricothyroid approximation and subluxation (CTAS) with postoperative speech therapy for pitch elevation in male-to-female transsexuals. STUDY DESIGN: Retrospective study of male-to-female transsexuals who underwent pitch-raising surgery between

Separate patient serum sodium medians from males and females provide independent information on analytical bias.

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Hansen, Steen Ingemann; Petersen, Per Hyltoft; Lund, Flemming; Fraser, Callum G; Sölétormos, György

2017-10-26

During monitoring of monthly medians of results from patients undertaken to assess analytical stability in routine laboratory performance, the medians for serum sodium for male and female patients were found to be significantly related. Daily, weekly and monthly patient medians of serum sodium for both male and female patients were calculated from results obtained on samples from the population >18 years on three analysers in the hospital laboratory. The half-range of medians was applied as an estimate of the maximum bias. Further, the ratios between the two medians were calculated. The medians of both genders demonstrated dispersions over time, but they were closely connected in like patterns, which were confirmed by the half-range of the ratios of medians for males and females that varied from 0.36% for daily, 0.14% for weekly and 0.036% for monthly ratios over all instruments. The tight relationship between the gender medians for serum sodium is only possible when raw laboratory data are used for calculation. The two patient medians can be used to confirm both and are useful as independent estimates of analytical bias during constant calibration periods. In contrast to the gender combined median, the estimate of analytical bias can be confirmed further by calculation of the ratios of medians for males and females.

Female vs. Male Ampelmännchen-Gender-Specific Reaction Times to Male and Female Traffic Light Figures

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Farid I. Kandil

2017-05-01

Full Text Available Traffic signs are important visual guiding signals for the safe navigation through complex road traffic. Interestingly, there is little variation in the traffic signs for cars around the world. However, remarkable variation exists for pedestrian traffic signs. Following up from an earlier study, we investigated the visual efficacy of female vs. male German Ampelmännchen pedestrian traffic signs. In a Stroop-like test, 30 subjects were presented with female and male go and no-go traffic light figures that were shown either in the corresponding or opposing color. Subjects had to indicate, based either solely on the form or the color of the figure, whether they were allowed to go. Accuracy and response times across all subjects did not differ for the female vs. male signs, indicating that Ampelfrau and Ampelmann signs have equal visual efficacy. However, subjects responded faster to signs of their own vs. the opposite gender. This preference for signs of one's own gender is in accordance with effects in social psychology described by social learning theory. An introduction of such novel traffic lights may, thus, contribute to higher compliance with the traffic sign signals.

Environmental concentrations of an androgenic progestin disrupts the seasonal breeding cycle in male three-spined stickleback (Gasterosteus aculeatus).

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Svensson, Johan; Fick, Jerker; Brandt, Ingvar; Brunström, Björn

2014-02-01

Synthetic steroid hormones from contraceptive pharmaceuticals have become global aquatic contaminants. Progestins, the synthetic analogs to progesterone, are receiving increasing attention as contaminants and have been shown to impair reproduction in fish and amphibians at low ng L(-1) concentrations. Certain progestins, such as levonorgestrel have androgenic properties and seem to be several orders of magnitude more potent in terms of reproductive impairment in fish than non-androgenic progestins and progestagens. We recently reported that levonorgestrel has strong androgenic effects in female three-spined sticklebacks (Gasterosteus aculeatus), including induction of the normally male-specific glue protein spiggin and suppression of vitellogenesis. In light of this we investigated if exposure to levonorgestrel could disrupt the highly androgen-dependent seasonal reproductive cycle in male sticklebacks. Male sticklebacks that were in the final stage of a breeding period were exposed to various concentrations of levonorgestrel for six weeks in winter conditions in terms of light and temperature, after which reproductive status was evaluated from gross morphology, histology and key gene transcript levels. During the experimental period the controls had transitioned from full breeding condition into the non-breeding state, including regression of secondary sex characteristics, cessation of spiggin production in the kidney, and resumption of spermatogenesis in the testes. This is ascribed to the natural drop in plasma androgen levels after breeding. However, in the groups concurrently exposed to levonorgestrel, transition to the non-breeding condition was dose-dependently inhibited. Our results show that levonorgestrel can disrupt the seasonal breeding cycle in male sticklebacks. The fitness costs of such an effect could be detrimental to natural stickleback populations. Some effects occurred at a levonorgestrel concentration of 6.5 ng L(-1), well within the range of

Sexual Selection on male cuticular hydrocarbons via male-male competition and female choice.

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Lane, S M; Dickinson, A W; Tregenza, T; House, C M

2016-07-01

Traditional views of sexual selection assumed that male-male competition and female mate choice work in harmony, selecting upon the same traits in the same direction. However, we now know that this is not always the case and that these two mechanisms often impose conflicting selection on male sexual traits. Cuticular hydrocarbons (CHCs) have been shown to be linked to both social dominance and male attractiveness in several insect species. However, although several studies have estimated the strength and form of sexual selection imposed on male CHCs by female mate choice, none have established whether these chemical traits are also subject to sexual selection via male-male competition. Using a multivariate selection analysis, we estimate and compare sexual selection exerted by male-male competition and female mate choice on male CHC composition in the broad-horned flour beetle Gnatocerus cornutus. We show that male-male competition exerts strong linear selection on both overall CHC abundance and body size in males, while female mate choice exerts a mixture of linear and nonlinear selection, targeting not just the overall amount of CHCs expressed but the relative abundance of specific hydrocarbons as well. We discuss the potential implications of this antagonistic selection with regard to male reproductive success. © 2016 The Authors. Journal of Evolutionary Biology published by John Wiley & Sons Ltd on behalf of European Society for Evolutionary Biology.

Adaptive capacity of female rabbits submitted to a change in breeding practices

Directory of Open Access Journals (Sweden)

M. Theau.Clément

2016-12-01

Full Text Available The aim of this study was to test the consequences of a change in breeding practices on 219 multiparous rabbit does over 2 reproductive cycles (5th and 6th insemination. Three rabbit breeding systems were defined I: intensive, S: semi-intensive and E: extensive, which varied for the females in terms of reproductive rhythm (RR: 35, 42 and 49 d, respectively and age at first insemination (20.6, 19.6 and 16.6 wk, respectively, and for kits in terms of age at weaning (32, 35 and 30 d, respectively and age at slaughter (63, 70 and 70 d, respectively. Females were submitted to one of the 3 systems from the 1st to the 4th artificial insemination (AI, and to another system from the 5th to the 6th AI, before returning to the initial system at the 7th AI. Consequently, they were allocated to 4 groups: I-S-I, S-I-S, S-E-S and E-S-E. Because of poor reproductive performance in the I system and despite a high growth of kits before weaning due to a more energetic diet for does, a sudden change from an I system to an S system significantly increased productivity at 28 d, from 3.37 to 5.04 kg/AI. Conversely, in the S and E systems, the females were not very sensitive to an intensification (groups S-I-S and E-S-E or an extensification (S-E-S of the breeding system, leading to similar productivity at 63 d (14.4 and 14.3 kg/AI, 14.4 and 13.5 kg/AI, 16.5 and 16.2 kg/AI, respectively, for groups S-I-S, E-S-E and S-E-S. The consequences of a return to the initial system deserve to be tested over a longer period.

Wolf (Canis lupus) generation time and proportion of current breeding females by age

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Mech, L. David; Barber-Meyer, Shannon M.; Erb, John

2016-01-01

Information is sparse about aspects of female wolf (Canis lupus) breeding in the wild, including age of first reproduction, mean age of primiparity, generation time, and proportion of each age that breeds in any given year. We studied these subjects in 86 wolves (113 captures) in the Superior National Forest (SNF), Minnesota (MN), during 1972–2013 where wolves were legally protected for most of the period, and in 159 harvested wolves from throughout MN wolf range during 2012–2014. Breeding status of SNF wolves were assessed via nipple measurements, and wolves from throughout MN wolf range, by placental scars. In the SNF, proportions of currently breeding females (those breeding in the year sampled) ranged from 19% at age 2 to 80% at age 5, and from throughout wolf range, from 33% at age 2 to 100% at age 7. Excluding pups and yearlings, only 33% to 36% of SNF females and 58% of females from throughout MN wolf range bred in any given year. Generation time for SNF wolves was 4.3 years and for MN wolf range, 4.7 years. These findings will be useful in modeling wolf population dynamics and in wolf genetic and dog-domestication studies.

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

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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.

Neutronics studies on the feasibility of developing fast breeder reactor with flexible breeding ratio

International Nuclear Information System (INIS)

Xiao Yunlong; Wu Hongchun; Zheng Youqi; Wang Kunpeng

2016-01-01

This paper investigates the feasibility of designing a flexible fast breeder reactor from the view of neutronics. It requires that the variable breeding ratio can be achieved in operating a fast reactor without significant changes of the core, including the minimum change of fuel assembly design, the minimum change of the core configuration and the same control system arrangement in the core. The sodium cooled fast reactor is investigated. Two difficulties are overcome: (1) the different excess reactivity is well controlled for different cores, especially for the one with small breeding ratio; (2) the maximum linear power density is well controlled while the breeding ratio changes. The optimizations are done to meet the requirements. The U–Pu–Zr alloy is applied to enhance the breeding. The enrichment-zoning technique with unfixed blanket assembly loading position is searched to get acceptable power distributions when the breeding ratio changes. And the control system is designed redundantly to fulfill the control needs. Then, the achieved breeding ratio can be adjusted from 1.1 to 1.4. The reactivity coefficients, temperature distributions and preliminary safety performances are evaluated to investigate the feasibility of the new concept. All the results show that it is feasible to develop the fast reactor with flexible breeding ratios, although it still highly relies on the advancement of the coolant flow control technology. (author)

Comparison of male and female foot shape.

Science.gov (United States)

Luo, Gangming; Houston, Vern L; Mussman, Martin; Garbarini, Maryanne; Beattie, Aaron C; Thongpop, Chaiya

2009-01-01

Morphological and geometric differences between male and female feet can be the decisive factor of whether well-fitting, functional, and comfortable footwear is available for both men and women. Optical scans, plaster wrap casts, and a set of manual measurements from the right feet of 51 female participants, aged 20 to 59 years (32 +/- 10.2 years), and 39 male participants, aged 22 to 71 years (47.1 +/- 12.1 years), were taken to determine which parameters were the most significant in characterizing pedal geometry and which had the largest difference between male and female feet. Analysis showed that the heel-to-ball length (ball length) of the male participants' feet (181.5 mm) was significantly longer, on average, than that of the female participants' feet (165.0 mm). The width of the male paticipants' feet at the ball, instep, and heel regions, as well as the ball circumference, normalized by the ball length, were all significantly larger on average, than the female test participants' feet. However, toe region, instep, and medial and lateral malleoli heights were larger, on average, for the female participants than for the male. The results show that female feet differ in size and shape from male feet and are not algebraically scaled, smaller versions of male feet, as is often assumed. The study shows that the average male participants' feet are longer than that of the female participants' feet, while the female feet are relatively narrower but higher than those of the male participants.

Morphostructural characterization of female and young male of naturalized Sul-mato-grossenses “Pantaneiros” sheep

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Daniele Portela de Oliveira

2014-02-01

Full Text Available Morphometric measurements are important to evaluate the variability, determine the racial standard and the existence of sexual dimorphism in genetic group. With this objective, were measured 20 morphometric measurements and one measurements of weight for 338 animals of the genetic group of Sul-mato-grossenses naturalized sheep belonging to Manoel de Barros Foundation and breeding at Centro Tecnologico de Ovinos from Anhanguera-Uniderp University and Federal University of the Grande Dourados. The statistical analyses were realized through software SAS. The females and young males showed short variation for morphometric measured of head and limbs region. However, higher variation was observed in the morphometric measurements taken from torso region, indicate that this region could be inserted in breeding programs like a selection criterion. The Pearson correlation coefficients between the morphostructural characteristics of females and young males, appears to have certain harmony degree in the morphostructural model. The females are characterized by animals with relatively large head, torso with proportional features and good angulations. The gender did not influence characteristics of the head region and body weight in the young animals. However, the characteristics of other regions, such as thoracic perimeter and posterior width of rump measured in the head region, and the perimeter of carpal and metacarpal in the limbs were influenced by gender in young animals.

Breeding performance in the Italian chicken breed Mericanel della Brianza

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Stefano P. Marelli

2010-11-01

Full Text Available In Italy, 90 local avian breeds were described, the majority (61% were classified extinct and only 8.9 % still diffused. Therefore, efforts for conservation of Italian avian breeds are urgently required. The aim of this study was to record the breeding performance of the Italian breed Mericanel della Brianza and multiply a small population, in order to develop a conservation program. Fourteen females and 8 males were available at the beginning of the reproductive season in 2009 and organized in 8 families (1 male/1-2 females kept in floor pens. Birds received a photoperiod of 14L:10D and fed ad libitum. Breeding performance was recorded from March to June. Egg production and egg weight were recorded daily; eggs were set every 2 weeks and fertility, embryo mortality and hatchability were recorded. Mean egg production was 37% and mean egg weight was 34±3.49 g. High fertility values were recorded in the first three settings, from 94 to 87%, and the overall mean fertility value was 81.6%. Overall hatchability was only 49.6% due to a high proportion of dead embryos. Embryo mortality occurred mainly between day 2 and 7 of incubation and during hatch. Highest hatchability values were recorded in setting 1 and 2, 69 and 60% respectively, and a great decrease was found in the following settings. Great variations in egg production, fertility, hatchability and embryo mortality were found among families. The present results are the basic knowledge on reproductive parameters necessary to improve the reproductive efficiency of the breed within a conservation plan.

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

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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.

BIRTH ORDER AND ANDROPHILIC MALE-TO-FEMALE TRANSSEXUALISM IN BRAZIL.

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Vanderlaan, Doug P; Blanchard, Ray; Zucker, Kenneth J; Massuda, Raffael; Fontanari, Anna Martha Vaitses; Borba, André Oliveira; Costa, Angelo Bradelli; Schneider, Maiko Abel; Mueller, Andressa; Soll, Bianca Machado Borba; Schwarz, Karine; Da Silva, Dhiordan Cardoso; Lobato, Maria Inês Rodrigues

2017-07-01

Previous research has indicated that biological older brothers increase the odds of androphilia in males. This finding has been termed the fraternal birth order effect. The maternal immune hypothesis suggests that this effect reflects the progressive immunization of some mothers to male-specific antigens involved in fetal male brain masculinization. Exposure to these antigens, as a result of carrying earlier-born sons, is hypothesized to produce maternal immune responses towards later-born sons, thus leading to female-typical neural development of brain regions underlying sexual orientation. Because this hypothesis posits mechanisms that have the potential to be active in any situation where a mother gestates repeated male fetuses, a key prediction is that the fraternal birth order effect should be observable in diverse populations. The present study assessed the association between sexual orientation and birth order in androphilic male-to-female transsexuals in Brazil, a previously unexamined population. Male-to-female transsexuals who reported attraction to males were recruited from a specialty gender identity service in southern Brazil (n=118) and a comparison group of gynephilic non-transsexual men (n=143) was recruited at the same hospital. Logistic regression showed that the transsexual group had significantly more older brothers and other siblings. These effects were independent of one another and consistent with previous studies of birth order and male sexual orientation. The presence of the fraternal birth order effect in the present sample provides further evidence of the ubiquity of this effect and, therefore, lends support to the maternal immune hypothesis as an explanation of androphilic sexual orientation in some male-to-female transsexuals.

Effects of playing a violent video game as male versus female avatar on subsequent aggression in male and female players.

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Yang, Grace S; Huesmann, L Rowell; Bushman, Brad J

2014-01-01

Previous research has shown that violent video games can increase aggression in players immediately after they play. The present research examines the effects of one subtle cue within violent video games that might moderate these effects-whether the avatar is male or female. One common stereotype is that males are more aggressive than females. Thus, playing a violent video game as a male avatar, compared to a female avatar, should be more likely to prime aggressive thoughts and inclinations in players and lead to more aggressive behavior afterwards. Male and female university students (N = 242) were randomly assigned to play a violent video game as a male or female avatar. After gameplay, participants gave an ostensible partner who hated spicy food hot sauce to eat. The amount of hot sauce given was used to measure aggression. Consistent with priming theory, results showed that both male and female participants who played a violent game as a male avatar behaved more aggressively afterwards than those who played as female avatar. The priming effects of the male avatar were somewhat stronger for male participants than for female participants, suggesting that male participants identified more with the male avatar than did the female participants. These results are particularly noteworthy because they are consistent with another recent experiment showing that playing a violent game as an avatar with a different stereotypically aggressive attribute (black skin color) stimulates more aggression than playing as an avatar without the stereotypically aggressive attribute (Yang et al., 2014, Social Psychological and Personality Science). © 2014 Wiley Periodicals, Inc.

Does hatching failure breed infidelity?

OpenAIRE

Malika Ihle; Bart Kempenaers; Wolfgang Forstmeier

2013-01-01

In socially monogamous species, the reasons for female infidelity are still controversial. It has been suggested that females could seek extra-pair copulations as an insurance against hatching failure caused by male infertility or incompatibility. In species where couples breed repeatedly, females could use previous hatching success as a cue to assess their partner’s infertility (or incompatibility). Hence, it has been predicted that females should increase their infidelity after experiencing...

When not to copy: female fruit flies use sophisticated public information to avoid mated males

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Loyau, Adeline; Blanchet, Simon; van Laere, Pauline; Clobert, Jean; Danchin, Etienne

2012-10-01

Semen limitation (lack of semen to fertilize all of a female's eggs) imposes high fitness costs to female partners. Females should therefore avoid mating with semen-limited males. This can be achieved by using public information extracted from watching individual males' previous copulating activities. This adaptive preference should be flexible given that semen limitation is temporary. We first demonstrate that the number of offspring produced by males Drosophila melanogaster gradually decreases over successive copulations. We then show that females avoid mating with males they just watched copulating and that visual public cues are sufficient to elicit this response. Finally, after males were given the time to replenish their sperm reserves, females did not avoid the males they previously saw copulating anymore. These results suggest that female fruit flies may have evolved sophisticated behavioural processes of resistance to semen-limited males, and demonstrate unsuspected adaptive context-dependent mate choice in an invertebrate.

Blood biochemical parameters in male American mink (Neovison vison before and during the breeding season

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Bogdan Lasota

2014-05-01

Full Text Available This study was aimed at selected blood biochemical parameters in the male American mink before (September-November and during the breeding (January-March season. Blood from 143 Black and Sapphire male mink at one year age was collected. The plasma was assayed for the concentration of glucose, total protein, cholesterol, HDL and LDL fractions, triacylglycerides (TG, and the activity of ALT and AST. Concentrations of glucose, protein, total and HDL/LDL cholesterol, and AST activity were generally slightly higher during the breeding season than during the non-breeding season, but remained within the reference range. In the case of ALT activity and TG concentration, the relations were reversed. The parameters studied in the Sapphire mink showed greater variation, both in- and out of the season. In Black and Sapphire males of the American mink, the studied parameters revealed slightly higher values during the breeding season than the non-breeding season. This will vary depending on the color variety. The decrease in TG concentration during the breeding season may indicate an increased energy demand due to ambient temperature falls, and/or may be a sign of increased energy consumption associated with physical exertion during mating. Consideration should be given to the nutrition of male mink during the breeding season.

Infants prefer female body phenotypes; infant girls prefer they have an hourglass shape.

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Gerianne M Alexander

2016-06-01

Full Text Available Adolescents and adults show preferences for male and female body shapes consistent with evolutionary theories of reproductive fitness and mate selection. However, when these preferences for females with narrow waists (i.e., 0.7 waist-to-hip ratio and men with broad shoulders (i.e., mesomorphic body shape emerge during the lifespan is largely unknown. To address this knowledge gap, eye-movements were tracked in 144 infants (3 to 18 months of age during computer presentation of three-dimensional human figures varying in body features thought relevant for reproductive success (e.g., secondary sex characteristics, waist-to-hip ratio. When presented with pairs of figures differing in apparent sex, male and female infants looked significantly longer at the female figure compared to the male figure, a new finding that extends previous research showing preferences for female faces in infancy. When presented with same-sex figures differing in characteristics associated with mate value, male and female infants looked longer at a low mate value male (i.e., an endomorphic body type compared to a high mate value male (i.e., a mesomorphic body type, a finding that replicates the results of previous research. In addition, the novel use of high and low mate value female figures showed a sex difference in visual attention, such that female infants looked longer at the high mate value female figure compared to the low mate female figure whereas male infants showed the opposite pattern of results. In sum, these findings suggest that infants generally do not possess preferences for adult-defined attractive male body shapes. However, infant girls’ greater attention to a female figure with an adult-preferred waist-to-hip ratio raises the possibility that evolved preferences for 0.7 waist-to-hip ratio influence girls’ later preference for toys representing females with an hourglass shape, perhaps supporting elaboration of adult social behaviors that enhance

Markers of bone resorption and calcium metabolism are related to dietary intake patterns in male and female bed rest subjects

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Smith, Scott M.; Zwart, S. R.; Hargens, A. r.

2006-01-01

Dietary potassium and protein intakes predict net endogenous acid production in humans. Intracellular buffers, including exchangeable bone mineral, play a crucial role in balancing chronic acid-base perturbations in the body; subsequently, chronic acid loads can potentially contribute to bone loss. Bone is lost during space flight, and a dietary countermeasure would be desirable for many reasons. We studied the ability of diet protein and potassium to predict levels of bone resorption markers in males and females. Identical twin pairs (8 M, 7 F) were assigned to 2 groups: bed rest (sedentary, SED) or bed rest with supine treadmill exercise in a lower body negative pressure chamber (EX). Diet was controlled for 3 d before and 30 d of bed rest (BR). Urinary Ca, N-telopeptide (NTX), and pyridinium crosslinks (PYD) were measured before and on days 5, 12, 19, and 26 of BR. Data were analyzed by Pearson correlation (P<0.05). The ratio of dietary animal protein/potassium intake was not correlated with NTX before BR for males or females, but they were positively correlated in both groups of males during bed rest. Dietary animal protein/potassium and urine Ca were correlated before and during bed rest for the males, and only during bed rest for the females. Conversely, the ratio of dietary vegetable protein/potassium intake was negatively correlated with urinary calcium during bed rest for the females, but there was no relationship between vegetable protein/potassium intake and bone markers for the males. These data suggest that the ratio of animal protein/potassium intake may affect bone, particularly in bed rest subjects. These data show that the type of protein and gender may be additional factors that modulate the effect of diet on bone metabolism during bed rest. Altering this ratio may help prevent bone loss on Earth and during space flight.

Condition-dependent female preference for male genitalia length is based on male reproductive tactics.

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Hernandez-Jimenez, Armando; Rios-Cardenas, Oscar

2017-12-06

There is extensive morphological variation of male genitalia across animals with internal fertilization, even among closely related species. Most studies attempting to explain this extraordinary diversity have focused on processes that occur post-copula (e.g. sperm competition, cryptic female choice). Only a few studies have focused on the pre-copula process of female preference. In addition, the extent to which this variation could be associated with the use of different reproductive tactics has yet to be explored. Here, we show that female preference for male genitalia length in two livebearing fishes depends on the type of reproductive tactic of the males being evaluated as well as the body condition of the female. In a species where all males coax females to acquire matings (courters), females preferred males with short genitalia. In a species with genetically influenced alternative reproductive tactics (courter males that only court and produce courter sons, sneaker males that use the coercive tactic of sneak chase and produce sneaker sons), female preference depended on an interaction between male tactic and female condition: females in good condition preferred courter males with short genitalia, and sneaker males with long genitalia. Our results suggest that female preference for male traits favourable to their sons may be an important factor contributing to the diversification of male genitalia. Despite the contrasting selection for genitalia length that our female preference tests suggest, we found no significant differences in genitalia length between coaxing (courters) and coercive (sneakers) males. Our study represents a starting point to more clearly understand the role of alternative reproductive tactics and variation in female mate preference in the evolution of male genitalia. © 2017 The Author(s).

Infants Prefer Female Body Phenotypes; Infant Girls Prefer They Have an Hourglass Shape.

Science.gov (United States)

Alexander, Gerianne M; Hawkins, Laura B; Wilcox, Teresa; Hirshkowitz, Amy

2016-01-01

Adolescents and adults show preferences for male and female body shapes consistent with evolutionary theories of reproductive fitness and mate selection. However, when these preferences for females with narrow waists (i.e., 0.7 waist-to-hip ratio) and men with broad shoulders (i.e., mesomorphic body shape) emerge during the lifespan is largely unknown. To address this knowledge gap, eye-movements were tracked in 146 infants (3-18 months of age) during computer presentation of three-dimensional human figures varying in body features thought relevant for reproductive success (e.g., secondary sex characteristics, waist-to-hip ratio). When presented with pairs of figures differing in apparent sex, male and female infants looked significantly longer at the female figure compared to the male figure, a new finding that extends previous research showing preferences for female faces in infancy. When presented with same-sex figures differing in characteristics associated with mate value, male and female infants looked longer at a low mate value male (i.e., an endomorphic body type) compared to a high mate value male (i.e., a mesomorphic body type), a finding that replicates the results of previous research. In addition, the novel use of high and low mate value female figures showed a sex difference in visual attention, such that female infants looked longer at the high mate value female figure compared to the low mate female figure whereas male infants showed the opposite pattern of results. In sum, these findings suggest that infants generally do not possess preferences for adult-defined attractive male body shapes. However, infant girls' greater attention to a female figure with an adult-preferred waist-to-hip ratio raises the possibility that evolved preferences for 0.7 waist-to-hip ratio influence girls' later preference for toys representing females with an hourglass shape, perhaps supporting elaboration of adult social behaviors that enhance reproductive success (e

Comparative toxic responses of male and female lizards (Eremias argus) exposed to (S)-metolachlor-contaminated soil.

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Chen, Li; Wang, Dezhen; Tian, Zhongnan; Di, Shanshan; Zhang, Wenjun; Wang, Fang; Zhou, Zhiqiang; Diao, Jinling

2017-08-01

Soil contamination caused by the widespread use of pesticides is one of the main environmental problems facing conservation organizations. (S)-metolachlor (SM) is a selective pre-emergent herbicide that poses potential risks to soil-related organisms such as reptiles. The present study elucidated the toxic effects of SM (3 and 30 mg/kg soil weight) in Eremias argus. The results showed that growth pattern was similar between the sexes in breeding season. For males, both kidney coefficient (KC) and testis coefficient in the exposure group were significantly different from those in the control group, while only KC in the high-dose group was significantly higher for females. Based on histopathological analysis, the livers of female lizards were more vulnerable than those of males in the exposure group. A reduction in total egg output was observed in SM exposed lizards. Accumulation studies indicated that skin exposure may be an important route for SM uptake in E. argus, and that the liver and lung have strong detoxification abilities. In addition, the body burdens of the lizards increased with increasing SM concentration in the soil. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fitness consequences of cooperative breeding in the Seychelles warbler

NARCIS (Netherlands)

Komdeur, Jan; Richardson, David; Burke, Terry

2006-01-01

Inclusive fitness benefits have been suggested as the selective force behind the evolution of cooperative breeding. Assessing the benefits accrued to individual males and females is crucial to understanding the sex-specific helping behavior observed in many cooperatively breeding species. We

Survival rates and lifetime reproduction of breeding male Cooper’s Hawks in Wisconsin, 1980-2005

Science.gov (United States)

Rosenfield, Robert N.; Bielefeldt, John; Rosenfield, Laura J.; Booms, Travis L.; Bozek, Michael A.

2009-01-01

There are few published data on annual survival and no reports of lifetime reproduction for breeding Cooper's Hawks (Accipiter cooperii). Breeding males (n  =  105) in central and southeastern Wisconsin had an annual mortality rate of 19%, or a survival rate of 81% for birds ≤10 years of age. We did not detect significant differences in mortality rates between urban and rural habitats, nor between the earlier 13 years and later 13 years of this study. Male Cooper's Hawks produced from zero to 32 nestlings during their lifetimes. Body mass or size appeared unrelated to annual survivorship and lifetime reproduction, although lifetime reproduction was correlated strongly with longevity of breeding males. Fifteen of 66 males (23%) produced most (53%) of the nestlings. Our studies occurred in an area where breeding populations may be increasing with some of the highest reported productivity indices and nesting densities for this species. Habitat used for nesting on our Wisconsin study areas may be less important for survivorship and lifetime reproduction than acquisition of a nesting area in which a male will breed throughout his life.

Optimization of temperature coefficient and breeding ratio for a graphite-moderated molten salt reactor

Energy Technology Data Exchange (ETDEWEB)

Zou, C.Y.; Cai, X.Z.; Jiang, D.Z.; Yu, C.G.; Li, X.X.; Ma, Y.W.; Han, J.L. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); CAS Center for Excellence in TMSR Energy System, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Chen, J.G., E-mail: chenjg@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); CAS Center for Excellence in TMSR Energy System, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Chinese Academy of Sciences, Shanghai 201800 (China)

2015-01-15

Highlights: • The temperature feedback coefficient with different moderation ratios for TMSR in thermal neutron region is optimized. • The breeding ratio and doubling time of a thermal TMSR with three different reprocessing schemes are analyzed. • The smaller hexagon size and larger salt fraction with more negative feedback coefficient can better satisfy the safety demands. • A shorter reprocessing time can achieve a better breeding ratio in a thermal TMSR. • The graphite moderator lifespan is compared with other MSRs and discussed. - Abstract: Molten salt reactor (MSR) has fascinating features: inherent safety, no fuel fabrication, online fuel reprocessing, etc. However, the graphite moderated MSR may present positive feedback coefficient which has severe implications for the transient behavior during operation. In this paper, the feedback coefficient and the breeding ratio are optimized based on the fuel-to-graphite ratio variation for a thorium based MSR (TMSR). A certain thermal core with negative feedback coefficient and relative high initial breeding ratio is chosen for the reprocessing scheme analysis. The breeding performances for the TMSR under different online fuel reprocessing efficiencies and frequencies are evaluated and compared with other MSR concepts. The results indicate that the thermal TMSR can get a breeding ratio greater than 1.0 with appropriate reprocessing scheme. The low fissile inventory in thermal TMSR leads to a short doubling time and low transuranic (TRU) inventory. The lifetime of graphite used for the TMSR is also discussed.

Female scent signals enhance the resistance of male mice to influenza.

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Ekaterina A Litvinova

Full Text Available BACKGROUND: The scent from receptive female mice functions as a signal, which stimulates male mice to search for potential mating partners. This searching behavior is coupled with infection risk due to sniffing both scent marks as well as nasal and anogenital areas of females, which harbor bacteria and viruses. Consideration of host evolution under unavoidable parasitic pressures, including helminthes, bacteria, viruses, etc., predicts adaptations that help protect hosts against the parasites associated with mating. METHODS AND FINDINGS: We propose that the perception of female signals by BALB/c male mice leads to adaptive redistribution of the immune defense directed to protection against respiratory infection risks. Our results demonstrate migration of macrophages and neutrophils to the upper airways upon exposure to female odor stimuli, which results in an increased resistance of the males to experimental influenza virus infection. This moderate leukocyte intervention had no negative effect on the aerobic performance in male mice. CONCLUSIONS: Our data provide the first demonstration of the adaptive immunological response to female odor stimuli through induction of nonspecific immune responses in the upper respiratory tract.

Baseline simple and complex reaction times in female compared to male boxers.

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Bianco, M; Ferri, M; Fabiano, C; Giorgiano, F; Tavella, S; Manili, U; Faina, M; Palmieri, V; Zeppilli, P

2011-06-01

The aim of the study was to compare baseline cognitive performance of female in respect to male amateur boxers. Study population included 28 female amateur boxers. Fifty-six male boxers, matched for age, employment and competitive level to female athletes, formed the control group. All boxers had no history of head concussions (except boxing). Each boxer was requested to: 1) fulfill a questionnaire collecting demographic data, level of education, occupational status, boxing record and number of head concussions during boxing; 2) undergo a baseline computerized neuropsychological (NP) test (CogSport) measuring simple and complex reaction times (RT). Female were lighter than male boxers (56±7 vs. 73.1±9.8 kg, Pknock-outs, etc.) correlated with NP scores. Female and male Olympic-style boxers have no (or minimal) differences in baseline cognitive performance. Further research with larger series of female boxers is required to confirm these findings.

Darcin: a male pheromone that stimulates female memory and sexual attraction to an individual male's odour

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McLean Lynn

2010-06-01

Full Text Available Abstract Background Among invertebrates, specific pheromones elicit inherent (fixed behavioural responses to coordinate social behaviours such as sexual recognition and attraction. By contrast, the much more complex social odours of mammals provide a broad range of information about the individual owner and stimulate individual-specific responses that are modulated by learning. How do mammals use such odours to coordinate important social interactions such as sexual attraction while allowing for individual-specific choice? We hypothesized that male mouse urine contains a specific pheromonal component that invokes inherent sexual attraction to the scent and which also stimulates female memory and conditions sexual attraction to the airborne odours of an individual scent owner associated with this pheromone. Results Using wild-stock house mice to ensure natural responses that generalize across individual genomes, we identify a single atypical male-specific major urinary protein (MUP of mass 18893Da that invokes a female's inherent sexual attraction to male compared to female urinary scent. Attraction to this protein pheromone, which we named darcin, was as strong as the attraction to intact male urine. Importantly, contact with darcin also stimulated a strong learned attraction to the associated airborne urinary odour of an individual male, such that, subsequently, females were attracted to the airborne scent of that specific individual but not to that of other males. Conclusions This involatile protein is a mammalian male sex pheromone that stimulates a flexible response to individual-specific odours through associative learning and memory, allowing female sexual attraction to be inherent but selective towards particular males. This 'darcin effect' offers a new system to investigate the neural basis of individual-specific memories in the brain and give new insights into the regulation of behaviour in complex social mammals. See associated

Darcin: a male pheromone that stimulates female memory and sexual attraction to an individual male's odour.

Science.gov (United States)

Roberts, Sarah A; Simpson, Deborah M; Armstrong, Stuart D; Davidson, Amanda J; Robertson, Duncan H; McLean, Lynn; Beynon, Robert J; Hurst, Jane L

2010-06-03

Among invertebrates, specific pheromones elicit inherent (fixed) behavioural responses to coordinate social behaviours such as sexual recognition and attraction. By contrast, the much more complex social odours of mammals provide a broad range of information about the individual owner and stimulate individual-specific responses that are modulated by learning. How do mammals use such odours to coordinate important social interactions such as sexual attraction while allowing for individual-specific choice? We hypothesized that male mouse urine contains a specific pheromonal component that invokes inherent sexual attraction to the scent and which also stimulates female memory and conditions sexual attraction to the airborne odours of an individual scent owner associated with this pheromone. Using wild-stock house mice to ensure natural responses that generalize across individual genomes, we identify a single atypical male-specific major urinary protein (MUP) of mass 18893Da that invokes a female's inherent sexual attraction to male compared to female urinary scent. Attraction to this protein pheromone, which we named darcin, was as strong as the attraction to intact male urine. Importantly, contact with darcin also stimulated a strong learned attraction to the associated airborne urinary odour of an individual male, such that, subsequently, females were attracted to the airborne scent of that specific individual but not to that of other males. This involatile protein is a mammalian male sex pheromone that stimulates a flexible response to individual-specific odours through associative learning and memory, allowing female sexual attraction to be inherent but selective towards particular males. This 'darcin effect' offers a new system to investigate the neural basis of individual-specific memories in the brain and give new insights into the regulation of behaviour in complex social mammals.See associated Commentary http://www.biomedcentral.com/1741-7007/8/71.

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.

Adult Gli2+/-;Gli3Δ699/+ Male and Female Mice Display a Spectrum of Genital Malformation.

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Fei He

Full Text Available Disorders of sexual development (DSD encompass a broad spectrum of urogenital malformations and are amongst the most common congenital birth defects. Although key genetic factors such as the hedgehog (Hh family have been identified, a unifying postnatally viable model displaying the spectrum of male and female urogenital malformations has not yet been reported. Since human cases are diagnosed and treated at various stages postnatally, equivalent mouse models enabling analysis at similar stages are of significant interest. Additionally, all non-Hh based genetic models investigating DSD display normal females, leaving female urogenital development largely unknown. Here, we generated compound mutant mice, Gli2+/-;Gli3Δ699/+, which exhibit a spectrum of urogenital malformations in both males and females upon birth, and also carried them well into adulthood. Analysis of embryonic day (E18.5 and adult mice revealed shortened anogenital distance (AGD, open ventral urethral groove, incomplete fusion of scrotal sac, abnormal penile size and structure, and incomplete testicular descent with hypoplasia in male mice, whereas female mutant mice displayed reduced AGD, urinary incontinence, and a number of uterine anomalies such as vaginal duplication. Male and female fertility was also investigated via breeding cages, and it was identified that male mice were infertile while females were unable to deliver despite becoming impregnated. We propose that Gli2+/-;Gli3Δ699/+ mice can serve as a genetic mouse model for common DSD such as cryptorchidism, hypospadias, and incomplete fusion of the scrotal sac in males, and a spectrum of uterine and vaginal abnormalities along with urinary incontinence in females, which could prove essential in revealing new insights into their equivalent diseases in humans.

Ego development in female-to-male transsexual couples.

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Fleming, M; Costos, D; MacGowan, B

1984-12-01

The ego development of 22 postoperative female-to-male transsexuals and their spouses or lovers with whom they had been living for a year or more was investigated. The transsexuals, their spouses, and a control group of 22 couples were administered the Washington University Sentence Completion Test of Ego Development, a projective measure of ego functioning. Ego development refers to the framework of meaning that the individual brings to an experience. The construct of ego development incorporates a series of sequential stages that integrate various frames of reference including cognitive style, interpersonal style, conscious preoccupation, and impulse control. These processes have received little attention in studies on female-to-male transsexuals who have successfully negotiated the social barrier of cross-living to the extent that they are living the male role in a heterosexual relationship. No significant differences in the distribution of ego development scores were found between the transsexuals and the control males, or between the transsexuals' spouses and the control spouses. Over 93% of the transsexuals and their spouses scored above the conformist level of ego development. These findings are discussed in terms of some of the previous literature on conformist thinking by transsexuals.

Non-invasive assessment of glucocorticoid and androgen metabolite levels in cooperatively breeding Damaraland mole-rats (Fukomys damarensis).

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Medger, Katarina; Bennett, Nigel C; Lutermann, Heike; Ganswindt, Andre

2018-05-18

Dominant females of cooperative breeding species often use aggression to suppress reproduction of subordinate females, resulting in subordinates experiencing stress-related increases in glucocorticoid levels, which may cause reproductive down-regulation. This would suggest a general pattern with higher glucocorticoid levels in subordinate compared to dominant individuals; however, the opposite was found in a number of cooperatively breeding species. Furthermore, breeding females of the cooperatively breeding Damaraland mole-rats (Fukomys damarensis) exhibit very high androgen concentrations during the wet season, presumably to support their breeding monopoly. Hormone analysis in Damaraland mole-rats have typically been measured using plasma and urine, but faecal analysis offers additional advantages especially for field studies on this species. The present study examines the suitability of Damaraland mole-rat faecal samples for determining glucocorticoid metabolite (fGCM) and androgen metabolite (fAM) concentrations using enzyme immunoassays. Using these assays, we further evaluated the effects of breeding status on fGCM and fAM concentrations in wild-caught and captive Damaraland mole-rats. Wild-caught breeding and non-breeding males and females exhibited no differences in fAM concentrations. Immunoreactive fGCM concentrations were only high in male breeders and comparatively low in non-breeders and breeding females. Concentrations of fAMs and fGCMs were similar in captive males and females, but fAM concentrations were elevated in captive compared to wild-caught individuals, which may be related to a higher reproductive activity due to removal from the breeding female. The relatively uniform fAM and fGCM concentrations found in wild-caught mole-rats may be explained by a stable colony structure during the dry season during which this study was conducted. Limited dispersal opportunities result in lower aggression and stress levels within a colony and as a result

Post-breeding migration routes of marine turtles from Bonaire and Klein Bonaire, Caribbean Netherlands

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Becking, L.E.; Christianen, M.J.A.; Nava, M.I.; Miller, N.; Willis, S.; Dam, Van, R.P.

2016-01-01

The management of small rookeries is key to conserving the regional genetic diversity of marine turtle populations and requires knowledge on population connectivity between breeding and foraging areas. To elucidate the geographic scope of the populations of marine turtles breeding at Bonaire and Klein Bonaire (Caribbean Netherlands) we examined the post-breeding migratory behavior of 5 female loggerheads Caretta caretta, 4 female green turtles Chelonia mydas, and 2 male and 13 female hawksbil...

A design study of high breeding ratio sodium cooled metal fuel core without blanket fuels

International Nuclear Information System (INIS)

Kobayashi, Noboru; Ogawa, Takashi; Ohki, Shigeo; Mizuno, Tomoyasu; Ogata, Takanari

2009-01-01

The metal fuel core is superior to the mixed oxide fuel core because of its high breeding ratio and compact core size resulting from hard neutron spectrum and high heavy metal densities. Utilizing these characteristics, a conceptual design for a high breeding ratio was performed without blanket fuels. The design conditions were set so a sodium void worth of less than 8 $, a core height of less than 150 cm, the maximum cladding temperature of 650degC, and the maximum fuel pin bundle pressure drop of 0.4 MPa. The breeding ratio of the resultant core was 1.34 with 6wt% zirconium content fuel. Applying 3wt% zirconium content fuel enhanced the breeding ratio up to 1.40. (author)

Supplementation of male pheromone on rock substrates attracts female rock lizards to the territories of males: a field experiment.

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José Martín

Full Text Available Many animals produce elaborated sexual signals to attract mates, among them are common chemical sexual signals (pheromones with an attracting function. Lizards produce chemical secretions for scent marking that may have a role in sexual selection. In the laboratory, female rock lizards (Iberolacerta cyreni prefer the scent of males with more ergosterol in their femoral secretions. However, it is not known whether the scent-marks of male rock lizards may actually attract females to male territories in the field.In the field, we added ergosterol to rocks inside the territories of male lizards, and found that this manipulation resulted in increased relative densities of females in these territories. Furthermore, a higher number of females were observed associated to males in manipulated plots, which probably increased mating opportunities for males in these areas.These and previous laboratory results suggest that female rock lizards may select to settle in home ranges based on the characteristics of scent-marks from conspecific males. Therefore, male rock lizards might attract more females and obtain more matings by increasing the proportion of ergosterol when scent-marking their territories. However, previous studies suggest that the allocation of ergosterol to secretions may be costly and only high quality males could afford it, thus, allowing the evolution of scent-marks as an honest sexual display.

Supplementation of Male Pheromone on Rock Substrates Attracts Female Rock Lizards to the Territories of Males: A Field Experiment

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Martín, José; López, Pilar

2012-01-01

Background Many animals produce elaborated sexual signals to attract mates, among them are common chemical sexual signals (pheromones) with an attracting function. Lizards produce chemical secretions for scent marking that may have a role in sexual selection. In the laboratory, female rock lizards (Iberolacerta cyreni) prefer the scent of males with more ergosterol in their femoral secretions. However, it is not known whether the scent-marks of male rock lizards may actually attract females to male territories in the field. Methodology/Principal Findings In the field, we added ergosterol to rocks inside the territories of male lizards, and found that this manipulation resulted in increased relative densities of females in these territories. Furthermore, a higher number of females were observed associated to males in manipulated plots, which probably increased mating opportunities for males in these areas. Conclusions/Significance These and previous laboratory results suggest that female rock lizards may select to settle in home ranges based on the characteristics of scent-marks from conspecific males. Therefore, male rock lizards might attract more females and obtain more matings by increasing the proportion of ergosterol when scent-marking their territories. However, previous studies suggest that the allocation of ergosterol to secretions may be costly and only high quality males could afford it, thus, allowing the evolution of scent-marks as an honest sexual display. PMID:22253895

Sex-dependent foraging effort and vigilance in coal-crested finches, Charitospiza eucosma (Aves: Emberizidae during the breeding season: evidence of female-biased predation?

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Pedro Diniz

2011-04-01

Full Text Available Sexual dimorphism in birds is often attributed to sexual selection, but another interpretation suggests the evolution of this phenomenon by natural selection. Predation may be an important selective pressure, acting mainly on females. In this study, I tested the latter hypothesis on the coal-crested finch (Charitospiza eucosma Oberholser, 1905 in a neotropical savanna of the Central Brazil (Cerrado. I used capture methods for ascertaining the sex ratio in the population, and focal observations to gather behavioral data. My results show that the sex ratio is skewed toward males (1:1.39. Males were more vigilant, vocalized for longer periods of time, and used higher perches than females. Females foraged more, spent more time on parental care and remained on the ground for longer periods than males. These results support the 'foraging effort hypothesis, suggesting that females are more preyed upon because they spend more time foraging. Ultimately, this may reflect the fact that females invest more on parental care than males. The sex-dependent parental investment may favor the evolution of different antipredator strategies in males and females: the camouflage in females as a less efficient strategy than vigilance in males.

Female professional divers. Similarities and differences between male and female professional divers.

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Irgens, Ågot; Troland, Kari; Grønning, Marit

2017-01-01

The aim of the present study was to explore the potential differences between female and male professional divers with regards to demographics, diving certificates, areas of diving, diving activity and health effects. The Norwegian Labour Inspection Authority's Diving certificate register contains data on all professional inshore divers who have held a certificate at any time since 1980. Forty nine per cent of these divers responded to the "Norwegian diver 2011" questionnaire. Of these divers 64 female and 1327 male divers completed the questionnaire about their professional diving career, certificate, year of onset and the year they stopped diving professionally if they were not still active in the diving industry. The level of general education was higher among female divers. More males than females were fully certified in diving. The mean age was lower among female than male fully certified divers. Fully certified female divers reported a lower total number of dives, shallower dives and diving for a shorter period of time than the male divers. They also had a lower percentage of work within the quay/construction sector and more often worked as teachers/instructors. A lower percentage of fully certified females than males had experienced decompression sickness (16.7% vs. 26.9%). Life-threatening events and psychologically challenging events were less common among females, as were adverse health effects. No such gender differences were seen for divers with a restricted certificate. The fully certified, female professional divers in our study had a very short diving career, reported fewer and shallower dives, and chose less physically demanding jobs than their male counterparts. They also had a higher level of education, reported less health problems and a better quality of life. The health effects seem to be related to the type of work rather than to gender.

Increased Cortical Thickness in Male-to-Female Transsexualism.

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Luders, Eileen; Sánchez, Francisco J; Tosun, Duygu; Shattuck, David W; Gaser, Christian; Vilain, Eric; Toga, Arthur W

2012-08-01

The degree to which one identifies as male or female has a profound impact on one's life. Yet, there is a limited understanding of what contributes to this important characteristic termed gender identity . In order to reveal factors influencing gender identity, studies have focused on people who report strong feelings of being the opposite sex, such as male-to-female (MTF) transsexuals. To investigate potential neuroanatomical variations associated with transsexualism, we compared the regional thickness of the cerebral cortex between 24 MTF transsexuals who had not yet been treated with cross-sex hormones and 24 age-matched control males. Results revealed thicker cortices in MTF transsexuals, both within regions of the left hemisphere (i.e., frontal and orbito-frontal cortex, central sulcus, perisylvian regions, paracentral gyrus) and right hemisphere (i.e., pre-/post-central gyrus, parietal cortex, temporal cortex, precuneus, fusiform, lingual, and orbito-frontal gyrus). These findings provide further evidence that brain anatomy is associated with gender identity, where measures in MTF transsexuals appear to be shifted away from gender-congruent men.

Markers of bone resorption and calcium metabolism are related to dietary intake patterns in male and female bed rest subjects

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Smith, Scott M.; Zwart, S. R.; Hargens, A. r.

2006-01-01

Dietary potassium and protein intakes predict net endogenous acid production in humans. Intracellular buffers, including exchangeable bone mineral, play a crucial role in balancing chronic acid-base perturbations in the body; subsequently, chronic acid loads can potentially contribute to bone loss. Bone is lost during space flight, and a dietary countermeasure would be desirable for many reasons. We studied the ability of diet protein and potassium to predict levels of bone resorption markers in males and females. Identical twin pairs (8 M, 7 F) were assigned to 2 groups: bed rest (sedentary, SED) or bed rest with supine treadmill exercise in a lower body negative pressure chamber (EX). Diet was controlled for 3 d before and 30 d of bed rest (BR). Urinary Ca, N-telopeptide (NTX), and pyridinium crosslinks (PYD) were measured before and on days 5, 12, 19, and 26 of BR. Data were analyzed by Pearson correlation (Pdietary animal protein/potassium intake was not correlated with NTX before BR for males or females, but they were positively correlated in both groups of males during bed rest. Dietary animal protein/potassium and urine Ca were correlated before and during bed rest for the males, and only during bed rest for the females. Conversely, the ratio of dietary vegetable protein/potassium intake was negatively correlated with urinary calcium during bed rest for the females, but there was no relationship between vegetable protein/potassium intake and bone markers for the males. These data suggest that the ratio of animal protein/potassium intake may affect bone, particularly in bed rest subjects. These data show that the type of protein and gender may be additional factors that modulate the effect of diet on bone metabolism during bed rest. Altering this ratio may help prevent bone loss on Earth and during space flight.

Patterns of Family Formation in Response to Sex Ratio Variation.

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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.

Selective breeding for increased pheromone production in the boll weevil (Coleoptera: Curculionidae)

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McCoy, J.R.; Wright, J.E.

1990-01-01

The male boll weevil, Anthonomus grandis grandis Boheman, uses an aggregating pheromone to attract females, after which mating often occurs. Sterile boll weevil release programs depend upon this phenomenon to produce sterile matings with feral females. In an effort to increase the effectiveness of the individual sterile male and thereby reduce the number of sterile males required per hectare, a selective-breeding system was used to increase the total pheromone produced by individual male boll weevils. This breeding program increased the total pheromone production by individual male boll weevils to 4.5 times that of the parent population. After irradiation-induced sterilization, there remained 2.2 times more pheromone produced by the selected strain. Therefore, these sterile weevils should be about 2.2 times more attractive to feral females than the parent weevils now in use, and they have the potential to reduce the number of sterile males required in a sterile release program

Tissue Trace Elements and Lipid Peroxidation in Breeding Female Bank Voles Myodes glareolus.

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Bonda-Ostaszewska, Elżbieta; Włostowski, Tadeusz; Łaszkiewicz-Tiszczenko, Barbara

2018-04-27

Recent studies have demonstrated that reproduction reduces oxidative damage in various tissues of small mammal females. The present work was designed to determine whether the reduction of oxidative stress in reproductive bank vole females was associated with changes in tissue trace elements (iron, copper, zinc) that play an essential role in the production of reactive oxygen species. Lipid peroxidation (a marker of oxidative stress) and iron concentration in liver, kidneys, and skeletal muscles of reproducing bank vole females that weaned one litter were significantly lower than in non-reproducing females; linear regression analysis confirmed a positive relation between the tissue iron and lipid peroxidation. The concentrations of copper were significantly lower only in skeletal muscles of reproductive females and correlated positively with lipid peroxidation. No changes in tissue zinc were found in breeding females when compared with non-breeding animals. These data indicate that decreases in tissue iron and copper concentrations may be responsible for the reduction of oxidative stress in reproductive bank vole females.

Traditional llama husbandry and breeding management in the Ayopaya region, Bolivia.

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Markemann, A; Valle Zárate, A

2010-01-01

The llama claims the largest population of the domestic South American camelids, most of which are raised in Bolivia. More than 53,000 rural families are dedicated to llama husbandry as part of their livelihood strategy. Contemporary Andean societies deliberately select animals for specific traits and employ substantial livestock management to secure subsistence. This study presents traditional llama husbandry and breeding management activities in the Ayopaya region, Bolivia. Traditional selection traits for male and female llamas are documented and assessed by a ranking and a ratio-scaled evaluation. Husbandry and management parameters are in concordance with other studies conducted in the region, but show a high variation. Average llama herd sizes are rather small (mu = 45.6). In some herds, breeding males are utilized for a long time and mix with other herds, causing concerns about inbreeding. Preferred trait groups for llama males according to farmers' responses were body conformation, fibre, testicle conformation, fleece colour and height at withers. Traditional selection criteria generally relate to the phenotype, but also include the commercially interesting fibre trait. The presented results should be considered in breeding and management programmes for the respective llama population to ensure sustainable use of this genetically and culturally valuable resource.

Male or female? Brains are intersex

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Daphna eJoel

2011-09-01

Full Text Available The underlying assumption in popular and scientific publications on sex differences in the brain is that human brains can take one of two forms male or female, and that the differences between these two forms underlie differences between men and women in personality, cognition, emotion and behavior. Documented sex differences in brain structure are typically taken to support this dimorphic view of the brain. However, neuroanatomical data reveal that sex interacts with other factors in utero and throughout life to determine the structure of the brain, and that because these interactions are complex, the result is a multi-morphic, rather than a dimorphic, brain. More specifically, here I argue that human brains are composed of an ever-changing heterogeneous mosaic of male and female brain characteristics (rather than being all male or all female that cannot be aligned on a continuum between a male brain and a female brain. I further suggest that sex differences in the direction of change in the brain mosaic following specific environmental events lead to sex differences in neuropsychiatric disorders.

Females engage in stronger relationships: positive and negative effects of shrubs are more intense for Poa ligularis females than for males.

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Graff, Pamela; Aguiar, Martin R; Almeida, Rocio J

2018-05-22

Dioecious plants are of particular concern in view of global environmental changes because reproductive females are more sensitive to abiotic stresses, thus compromising population viability. Positive interactions with other plants may counteract the direct effects of any abiotic environmental stress, allowing them to thrive and maintain a viable population in suboptimal habitats, although this process has not been tested for dioecious species. Furthermore, almost no data are available on the outcome of such species interactions and their link with local spatial patterns and sex ratios. We set up a field experiment with Poa ligularis, a dioecious native grass from the arid grasslands of South America. We studied the interaction of male and female plants with cushion shrubs of contrasting ecological strategies. We experimentally limited direct shrub-grass competition for soil moisture and transplanted plants to evaluate the amelioration of abiotic stress by shrub canopies (i.e. sun and wind) on grasses. We also studied the distribution of naturally established female and male plants to infer process-pattern relationships. Positive canopy effects as well as negative below-ground effects were more intense for females than for males. Deep-rooted Mulinum spinosum shrubs strongly facilitated survival, growth and reproduction of P. ligularis females. Naturally established female plants tended to distribute more closely to Mulinum than co-occurring males. Female growth suffered intensive negative root competition from the shallow-rooted Senecio filaginoides shrub. Interactions with other plants may reduce or enhance the effect of abiotic stresses on the seemingly maladapted sex to arid environments. We found that these biased interactions are evident in the current organization of sexes in the field, confirming our experimental findings. Therefore, indirect effects of climate change on population sex ratios may be expected if benefactor species abundances are

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

Male versus Female Attitudes toward Stuttering

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St. Louis, Kenneth O.

2012-01-01

Purpose: The study investigated the extent to which differences existed between public attitudes of males versus females. Method: One hundred adults, 50 males and 50 females, were chosen at random from each of 50 study samples comprising a total of 3371 respondents in a database archive who had completed the "Public Opinion Survey of Human…

Morphological study of Socorro Island Merino sheep and its crosses with hair breeds.

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Hernández, Juan Augusto; Lepe, Marissa; Macedo, Rafael; Arredondo, Victalina; Cortez, Carlos Eliseo; García, Luis Jorge; Prado, Omar

2017-01-01

A study was conducted with the objective to characterize the morphology of Socorro Island Merino sheep. A total of 67 sheep, 62 females, 26 purebred and 36 crossbred with hair breeds, and five males were scored for 10 body measurements in addition to live weight, and four racial and seven functional indices were calculated. The influence of sex and crossbreeding on the body measurements and indices was analyzed by one-way analysis of variance, and morphological harmony was determined using Spearman correlation. With exception of rump length, body measurements and live weight were significantly greater in males than in females. Sexual dimorphism was 1.21, with males being 78 % heavier than females. Socorro Island Merino sheep were dolichocephalous, elipometric, with a convex curve rump, and with a high and low morphological harmony for females and males, respectively. They had undefined zootechnical aptitude tended toward dairy phenotype as long as crossbreeding with hair breeds did not affect their functional or productive aptitude. It can be concluded that Socorro Island Merino sheep is a new biotype of the Merino breed, which is necessary to preserve and evaluate as a source of genetic characteristics such as adaptation to harsh environmental conditions.

Gene Linked to Excess Male Hormones in Female Infertility Disorder

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... April 15, 2014 Gene linked to excess male hormones in female infertility disorder Discovery by NIH-supported ... may lead to the overproduction of androgens — male hormones similar to testosterone — occurring in women with polycystic ...

A combined approach to heat stress effect on male fertility in Nasonia vitripennis: from the physiological consequences on spermatogenesis to the reproductive adjustment of females mated with stressed males.

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Marlène Chirault

Full Text Available In recent years, several studies have shown a decline in reproductive success in males in both humans and wildlife. Research on male fertility has largely focused on vertebrates, although invertebrates constitute the vast majority of terrestrial biodiversity. The reduction of their reproductive capacities due to environmental stresses can have strong negative ecological impacts, and also dramatic consequences on world food production if it affects the reproductive success of biological control agents, such as parasitic wasps used to control crop pests. Here Nasonia vitripennis, a parasitic wasp of various fly species, was studied to test the effects of 24h-heat stress applied during the first pupal stage on male fertility. Results showed that only primary spermatocytes were present at the first pupal stage in all cysts of the testes. Heat stress caused a delay in spermatogenesis during development and a significant decrease in sperm stock at emergence. Females mated with these heat-stressed males showed a reduce sperm count stored in their spermatheca. Females did not appear to distinguish heat-stressed from control males and did not remate more frequently to compensate for the lack of sperm transferred. As a result, females mated with heat-stressed males produced a suboptimal lifetime offspring sex ratio compared to those mated with control males. This could further impact the population dynamics of this species. N. vitripennis appears to be an interesting biological model to study the mechanisms of subfertility and its consequence on female reproductive strategies and provides new research perspectives in both invertebrates and vertebrates.

A combined approach to heat stress effect on male fertility in Nasonia vitripennis: from the physiological consequences on spermatogenesis to the reproductive adjustment of females mated with stressed males.

Science.gov (United States)

Chirault, Marlène; Lucas, Christophe; Goubault, Marlène; Chevrier, Claude; Bressac, Christophe; Lécureuil, Charlotte

2015-01-01

In recent years, several studies have shown a decline in reproductive success in males in both humans and wildlife. Research on male fertility has largely focused on vertebrates, although invertebrates constitute the vast majority of terrestrial biodiversity. The reduction of their reproductive capacities due to environmental stresses can have strong negative ecological impacts, and also dramatic consequences on world food production if it affects the reproductive success of biological control agents, such as parasitic wasps used to control crop pests. Here Nasonia vitripennis, a parasitic wasp of various fly species, was studied to test the effects of 24h-heat stress applied during the first pupal stage on male fertility. Results showed that only primary spermatocytes were present at the first pupal stage in all cysts of the testes. Heat stress caused a delay in spermatogenesis during development and a significant decrease in sperm stock at emergence. Females mated with these heat-stressed males showed a reduce sperm count stored in their spermatheca. Females did not appear to distinguish heat-stressed from control males and did not remate more frequently to compensate for the lack of sperm transferred. As a result, females mated with heat-stressed males produced a suboptimal lifetime offspring sex ratio compared to those mated with control males. This could further impact the population dynamics of this species. N. vitripennis appears to be an interesting biological model to study the mechanisms of subfertility and its consequence on female reproductive strategies and provides new research perspectives in both invertebrates and vertebrates.

The threat of male-to-female erotic transference.

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Celenza, Andrea

2006-01-01

Vignettes from an ongoing psychoanalysis with a patient, Michael, are presented to illustrate the various dimensions of the erotic transference at different phases of the treatment. The relation to power, the experience and expression of aggression, how these may be organized by gender, and the female analyst's countertransference are discussed as potentially fostering or inhibitory in the development of an erotic transference. Traditional sociocultural gender stereotypes kept alive in fantasy can cause female analysts to subtly foreclose the impending threat of an intense erotic transference with male analysands due to a fear of outwardly directed male aggression. It is suggested that the maternal/containing transference can be unconsciously fostered by both analyst and analysand to defensively avoid expression of the aggressivized erotic transference in its full intensity. Similarities and differences in cases of sexual boundary violations with opposite-gender pairings are discussed.

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

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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.

Spatial distribution of breeding Pied Flycatchers Ficedula hypoleuca in respect to their natal sites

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Sokolov, L.

2004-06-01

Full Text Available Study of philopatry and dispersal of pied flycatchers Ficedula hypoleuca was launched on the Courish Spit (SE Baltic in 1981. Since then, ca. 9,000 nestlings were ringed at different sites in the Russian part of the Courish Spit. A total of 557 individuals ringed as pulli were recaptured in subsequent seasons in the study area. Both males and females are more often recaptured in the plots where they were ringed than in other plots. These results were interpreted in the framework of the hypothesis forwarded by Löhrl (1959 and supported by Berndt & Winkel (1979. These authors suggested that cavity nesters (pied flycatchers and collared flycatchers F. albicollis imprint their future local breeding area during the period of postfledging exploration. Birds that survive until the next spring, return to these imprinted areas to breed. A similar study done by Sokolov et al. (1984 on the Courish Spit in an open nesting species, the chaffinch Fringilla coelebs, confirmed this finding. We assumed that juvenile pied flycatchers disperse for varying distances during their postfledging movements and imprint a local area, some 1–5 kilometres in diameter. This area is the goal of their migration next spring. It is suggested that in spring, yearlings are non–randomly distributed in respect to the area they have imprinted as juveniles. Recently, Vysotsky (2000, 2001 re–analysed the same data on philopatry of pied flycatchers on the Courish Spit and forwarded an alternative hypothesis. He suggests that juveniles, both males and females, do not imprint any local area during the postfledging period, but are distributed randomly across the area of several dozens of kilometres in spring. Vysotsky was able to show that distribution of distances of natal dispersal did not differ from the random pattern the study plot which was an 8.5 km long line of nest boxes along the Courish Spit. The aim of this study was to test these two alternative hypotheses. To do so, we

Male-to-female transsexuals have female neuron numbers in a limbic nucleus

NARCIS (Netherlands)

Kruijver, F. P.; Zhou, J. N.; Pool, C. W.; Hofman, M. A.; Gooren, L. J.; Swaab, D. F.

2000-01-01

Transsexuals experience themselves as being of the opposite sex, despite having the biological characteristics of one sex. A crucial question resulting from a previous brain study in male-to-female transsexuals was whether the reported difference according to gender identity in the central part of

Experimentally reduced corticosterone release promotes early breeding in black-legged kittiwakes.

Science.gov (United States)

Goutte, Aurélie; Clément-Chastel, Céline; Moe, Børge; Bech, Claus; Gabrielsen, Geir Wing; Chastel, Olivier

2011-06-15

Breeding at the right time is important for successful reproduction. In birds, stressful environmental conditions are known to delay the timing of breeding but the underlying mechanisms are poorly understood. The stress hormone corticosterone appears to be a good candidate for mediating egg-laying date according to early environmental conditions and physiological state. By experimentally reducing the release of corticosterone in black-legged kittiwakes during the pre-laying period, we tested whether egg-laying date was mechanistically linked to corticosterone levels. Male and female kittiwakes were implanted with a low dose of exogenous corticosterone to inhibit endogenous corticosterone production. According to our predictions, the experimental reduction of corticosterone release was paralleled by a significant advancement of egg laying in females (around 4 days earlier). In addition, females with experimentally reduced corticosterone release gained mass during the pre-laying period compared with controls. Ultimately, the advancement of egg laying in females with experimentally reduced corticosterone levels was associated with an enhanced breeding success. This effect was strongly sex specific. In corticosterone-treated male kittiwakes, egg-laying date and reproductive success were not affected, but breeding probability was lower than in controls. This corticosterone treatment did not influence immediate clutch size, or return rate and breeding decision the following year. Our results support the hypothesis that corticosterone secretion during the pre-laying period mediates the timing of breeding in this long-lived seabird, possibly through the dynamics of energy reserves.

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

Costs of Reproduction in Breeding Female Mallards: Predation Risk during Incubation Drives Annual Mortality

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Todd W. Arnold

2012-06-01

Full Text Available The effort expended on reproduction may entail future costs, such as reduced survival or fecundity, and these costs can have an important influence on life-history optimization. For birds with precocial offspring, hypothesized costs of reproduction have typically emphasized nutritional and energetic investments in egg formation and incubation. We measured seasonal survival of 3856 radio-marked female Mallards (Anas platyrhynchos from arrival on the breeding grounds through brood-rearing or cessation of breeding. There was a 2.5-fold direct increase in mortality risk associated with incubating nests in terrestrial habitats, whereas during brood-rearing when breeding females occupy aquatic habitats, mortality risk reached seasonal lows. Mortality risk also varied with calendar date and was highest during periods when large numbers of Mallards were nesting, suggesting that prey-switching behaviors by common predators may exacerbate risks to adults in all breeding stages. Although prior investments in egg laying and incubation affected mortality risk, most relationships were not consistent with the cost of reproduction hypothesis; birds with extensive prior investments in egg production or incubation typically survived better, suggesting that variation in individual quality drove both relationships. We conclude that for breeding female Mallards, the primary cost of reproduction is a fixed cost associated with placing oneself at risk to predators while incubating nests in terrestrial habitats.

Post-mating interactions and their effects on fitness of female and male Echinothrips americanus (Thysanoptera: Thripidae), a new insect pest in China.

Science.gov (United States)

Li, Xiao-Wei; Jiang, Hong-Xue; Zhang, Xiao-Chen; Shelton, Anthony M; Feng, Ji-Nian

2014-01-01

Post-mating, sexual interactions of opposite sexes differ considerably in different organisms. Post-mating interactions such as re-mating behavior and male harassment can affect the fitness of both sexes. Echinothrips americanus is a new insect pest in Mainland China, and little is known about its post-mating interactions. In this study, we observed re-mating frequency and male harassment frequency and their effects on fitness parameters and offspring sex ratios of E. americanus females. Furthermore, we tested the impact of mating and post-mating interactions on fitness parameters of males. Our results revealed that the re-mating frequency in female adults was extremely low during a 30-day period. However, post-mating interactions between females and males, consisting mainly of male harassment and female resistance, did occur and significantly reduced female longevity and fecundity. Interestingly, increased access to males did not affect the ratio of female offspring. For males, mating dramatically reduced their longevity. However, post-mating interactions with females had no effects on the longevity of mated males. These results enrich our basic knowledge about female and male mating and post-mating behaviors in this species and provide important information about factors that may influence population regulation of this important pest species.

Post-mating interactions and their effects on fitness of female and male Echinothrips americanus (Thysanoptera: Thripidae, a new insect pest in China.

Directory of Open Access Journals (Sweden)

Xiao-Wei Li

Full Text Available Post-mating, sexual interactions of opposite sexes differ considerably in different organisms. Post-mating interactions such as re-mating behavior and male harassment can affect the fitness of both sexes. Echinothrips americanus is a new insect pest in Mainland China, and little is known about its post-mating interactions. In this study, we observed re-mating frequency and male harassment frequency and their effects on fitness parameters and offspring sex ratios of E. americanus females. Furthermore, we tested the impact of mating and post-mating interactions on fitness parameters of males. Our results revealed that the re-mating frequency in female adults was extremely low during a 30-day period. However, post-mating interactions between females and males, consisting mainly of male harassment and female resistance, did occur and significantly reduced female longevity and fecundity. Interestingly, increased access to males did not affect the ratio of female offspring. For males, mating dramatically reduced their longevity. However, post-mating interactions with females had no effects on the longevity of mated males. These results enrich our basic knowledge about female and male mating and post-mating behaviors in this species and provide important information about factors that may influence population regulation of this important pest species.

Using Preferred Attribute Elicitation to Determine How Males and Females Evaluate Beer.

Science.gov (United States)

Muggah, Elizabeth M; McSweeney, Matthew B

2017-08-01

The variety of beers available for consumption has increased due to the recent emergence of many craft brewing operations and it has been suggested that this is affecting how consumers evaluate beer. Currently, beer consumers are mostly male and only 20% of women are primarily beer drinkers. The main objective of this project is to compare and contrast descriptions of beer products created by males and females. The preferred attribute elicitation (PAE) method was used to create a description of 4 beers common to residents of Nova Scotia, Canada. Four PAE sessions were held: 2 sessions consisted of females (n = 16 and 15) and 2 sessions of males (n = 11 and 17). Four beer samples were chosen from locally available commercial beers, 2 of these samples were considered to be craft-brewed beer and the other samples were nationally available brands (macrobrewed). Both the males and females generated descriptions that included 5 identical terms; however, they differed in the importance they assigned to each attribute. Notably, bitterness was perceived to be of more importance to female panelists. Throughout all PAE sessions, the craft-brewed beers were associated with considerably more sensory attributes than the macrobrewed beers. It can be concluded that both the female and male groups found discernible differences between the craft and macrobrewed beers; however, they place importance on different sensory attributes. © 2017 Institute of Food Technologists®.

FUNCTIONAL MALE STERILITY AND ITS USE IN BREEDING OF VEGETABLE AND MELON CROPS

OpenAIRE

A. N. Bocharnikov

2014-01-01

The article describes the manifestation of functional male sterility and its importance in the breeding of melons. Utilization of functional male sterility allows solving the problem effective hybrid seed production.

Construction of a male sterility system for hybrid rice breeding and seed production using a nuclear male sterility gene

OpenAIRE

Chang, Zhenyi; Chen, Zhufeng; Wang, Na; Xie, Gang; Lu, Jiawei; Yan, Wei; Zhou, Junli; Tang, Xiaoyan; Deng, Xing Wang

2016-01-01

Nuclear male sterility is common in flowering plants, but its application in hybrid breeding and seed production is limited because of the inability to propagate a pure male sterile line for commercial hybrid seed production. Here, we characterized a rice nuclear gene essential for sporophytic male fertility and constructed a male sterility system that can propagate the pure male sterile seeds on a large scale. This system is fundamentally advantageous over the current cytoplasmic male steril...

Responsiveness to Ipratropium Bromide in Male and Female Patients with Mild to Moderate Chronic Obstructive Pulmonary Disease

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Xuan Li

2017-05-01

Conclusion: Ipratropium induces a larger bronchodilator response in female than in male patients and the benefits are particularly notable in non-obese females. Female lungs have greater gene expression for the M3 muscarinic receptor relative to M2 receptors than male lungs. Female patients are thus more likely to benefit from ipratropium than male COPD patients.

Segregation distortion causes large-scale differences between male and female genomes in hybrid ants.

Science.gov (United States)

Kulmuni, Jonna; Seifert, Bernhard; Pamilo, Pekka

2010-04-20

Hybridization in isolated populations can lead either to hybrid breakdown and extinction or in some cases to speciation. The basis of hybrid breakdown lies in genetic incompatibilities between diverged genomes. In social Hymenoptera, the consequences of hybridization can differ from those in other animals because of haplodiploidy and sociality. Selection pressures differ between sexes because males are haploid and females are diploid. Furthermore, sociality and group living may allow survival of hybrid genotypes. We show that hybridization in Formica ants has resulted in a stable situation in which the males form two highly divergent gene pools whereas all the females are hybrids. This causes an exceptional situation with large-scale differences between male and female genomes. The genotype differences indicate strong transmission ratio distortion depending on offspring sex, whereby the mother transmits some alleles exclusively to her daughters and other alleles exclusively to her sons. The genetic differences between the sexes and the apparent lack of multilocus hybrid genotypes in males can be explained by recessive incompatibilities which cause the elimination of hybrid males because of their haploid genome. Alternatively, differentiation between sexes could be created by prezygotic segregation into male-forming and female-forming gametes in diploid females. Differentiation between sexes is stable and maintained throughout generations. The present study shows a unique outcome of hybridization and demonstrates that hybridization has the potential of generating evolutionary novelties in animals.

Variation in the gonadotrophin-releasing hormone-1 and the song control system in the tropical breeding rufous-collared sparrow (Zonotrichia capensis) is dependent on sex and reproductive state.

Science.gov (United States)

Stevenson, Tyler J; Small, Thomas W; Ball, Gregory F; Moore, Ignacio T

2012-08-01

Seasonal breeding in temperate zone vertebrates is characterised by pronounced variation in both central and peripheral reproductive physiology as well as behaviour. In contrast, many tropical species have a comparatively longer and less of a seasonal pattern of breeding than their temperate zone counterparts. These extended, more "flexible" reproductive periods may be associate with a lesser degree of annual variation in reproductive physiology. Here we investigated variation in the neuroendocrine control of reproduction in relation to the changes in the neural song control system in a tropical breeding songbird the rufous-collared sparrows (Zonotrichia capensis). Using in situ hybridization, we show that the optical density of GnRH1 mRNA expression is relatively constant across pre-breeding and breeding states. However, males were found to have significantly greater expression compared to females regardless of breeding state. Both males and females showed marked variation in measures of peripheral reproductive physiology with greater gonadal volumes and concentrations of sex steroids in the blood (i.e. testosterone in males; estrogen in females) during the breeding season as compared to the pre-breeding season. These findings suggest that the environmental cues regulating breeding in a tropical breeding bird ultimately exert their effects on physiology at the level of the median eminence and regulate the release of GnRH1. In addition, histological analysis of the song control system HVC, RA and Area X revealed that breeding males had significantly larger volumes of these brain nuclei as compared to non-breeding males, breeding females, and non-breeding females. Females did not exhibit a significant difference in the size of song control regions across breeding states. Together, these data show a marked sex difference in the extent to which there is breeding-associated variation in reproductive physiology and brain plasticity that is dependent on the reproductive

Psychographic Segments of College Females and Males in Relation to Substance Use Behaviors.

Science.gov (United States)

Suragh, Tiffany Ashley; Berg, Carla J; Nehl, Eric J

2013-09-01

A common commercial marketing segmentation technique is to divide a population into groups based on psychographic characteristics (i.e., attitudes and interests). We used this approach to define segments of female and male college students and examine substance use differences. We administered an online survey to 24,055 students at six colleges in the Southeastern United States (response rate 20.1%, n = 4,840), obtaining complete data from 3,469 participants. We assessed sociodemographics, psychographic factors such as those used by the tobacco industry to define market segments, and substance use (cigarettes, other tobacco products, alcohol, and marijuana). Cluster analysis was conducted among females and males using 15 psychographic measures (sensation seeking, Big Five personality traits, and nine measures adapted from tobacco industry documents), identifying three segments per sex. Safe responsibles were characterized by high levels of agreeableness, conscientiousness, emotional stability, academic achievement, and religious service attendance. Stoic individualists were characterized by low extraversion, sensation seeking, and openness. Thrill-seeking socializers were characterized by high levels of sensation seeking and extraversion. Among females, thrill-seeking socializers were significantly more likely than safe responsibles to have used any substance in the prior 30 days (odds ratio [OR] = 2.04, 95% confidence interval [CI] [1.65, 2.52]; Nagelkerke R 2 = .084). Among males, stoic individualists (OR = 1.50, CI [1.08, 2.08]) and thrill-seeking socializers (OR = 1.53, CI [1.09, 2.13]) were more likely than safe responsibles to have used substances in the past 30 days (Nagelkerke R 2 : .109). Psychographic segmentation can identify young adult subgroups with differing psychographic and substance use profiles and inform health campaigns and messaging targeting youth.

Comparison between morphometric measurements os current herd Mangalarga Marchador males and breed champions

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Juliano Martins Santiago

2013-01-01

Full Text Available Equines morphometric analysis is an important method of selection related to functionality of the species. Mangalarga Marchador is the most important horse Brazilian breed and its evolution can be observed in specialized exhibition where owners expase their herd with the breed exponents, adopting them as selection parameters. In this context the study aimed to compare the morphometric measures of Mangalarga Marchador males herd with the champions of breed, using as parameters breed standards and Eclectic System of Proportions for saddle horse. Experimental design was completely randomized and treatments were the Mangalarga Marchador male herd, represented by all horses registered from 2000 to 2012, wich had measurements stored in Associação Brasileira de Criadores do Cavalo Mangalarga Marchador (ABCCMM service studbook database, totaling 15,482 animals, and the champions of breed, represented by 222 horses champions who participated of the 29th, 30th or 31th Exposição Nacional do Cavalo Mangalarga Marchador. Variables evaluated were height at withers and at rump, length of the head, neck, dorse, rump, shoulder and body, width of head and of rump, thoracic perimeter and cannon perimeter. Average linear measurements were related to length of head, according to Eclectic System of Proportions for saddle horse. Results were submitted to variance analysis and averages were compared by Fisher test (p<0.05. Regarding the current herd of males Mangalarga Marchador, the champions of the race showed greater length of neck, dorse, rump and body, height at withers and at rump, width of rump, cannon perimeter and shorter length of the shoulder. It was concluded that although larger, the champions horses Mangalarga Marchador are proportionally similar to current herd. Mangalarga Marchador horses have not yet reached the height considered ideal by breed standard and their proportions are different from those recommended by Eclectic System of Proportions for

Bone Composition in Male and Female Göttingen Minipigs Fed Variously Restrictedly and near ad Libitum

DEFF Research Database (Denmark)

Bollen, P. J. A.; Lemmens, A. G.; Beynen, A. C.

2006-01-01

diet 2 was a high fat, low fibre diet. A higher level of feed intake led to a significant increase in the following parameters: body weight development, bone size (length and width of rib and femur), bone volume (rib), bone (rib) dry matter and ash content (mg), as well as bone density (femur...... development, bone volume, and dry matter and ash content of the rib (mg) as compared to males. Also bone mineral concentrations in the femur, expressed as calcium, phosphorus and magnesium in mg/cm3, were significantly higher in females as compared to males, as was the Ca:Pi ratio. Bone density measurements...... of the femur’s proximal and distal segment, and total femur bone density (g/cm2) were significantly higher in females as compared to males. Feed conversion in females was significantly lower than in males. This study illustrates that female and male minipigs show distinct differences in body and bone...

The Great Recession of 2007 in the United States and the male: female ratio at birth.

Science.gov (United States)

Grech, Victor

2015-01-01

Male live births slightly exceed female live births by approximately 3%. The ratio of male to total live births is conventionally represented as M/F. Many factors have been shown to affect M/F, mainly privation, toxins, and stress, all of which reduce M/F. Population stress may be engendered by natural phenomena such as earthquakes and man-made events such as short wars, terrorist attacks, and contracting economies. This study was conducted to ascertain whether the onset of the "Great Recession" (2007) was associated with changes in M/F in the United States (US). Annual monthly live births by gender for January 2006 to December 2008 were obtained from United States Centres for Disease Control and Prevention. In 2007, there were 4316233 live births [M/F: 0.51157; 95% confidence intervals: 0.51110-0.51205). M/F rose between January and June, and then fell sharply between August and December. M/F was statistically significantly lower in the second half of 2007 (p=0.007). The dip in M/F from June to July was also significant (p=0.02). These findings were not replicated in the amalgamated data for 2006 and 2008. The United States housing boom of the mid-2000s was fueled by rising house prices and cheap mortgages given to credit-poor buyers. A halt in rising house prices resulted in defaults and foreclosures, triggering the worst financial crisis since the Great Depression. The associated stress appears to have decreased M/F in the US.

EVOLUTION OF MORPHOMETRIC MEASURES IN THE MANGALARGA MARCHADOR BREED

Directory of Open Access Journals (Sweden)

JULIANO MARTINS SANTIAGO

2016-01-01

Full Text Available The Mangalarga Marchador breed accounts for the largest horse herd in Brazil and has been experiencing national and international expansion. Nevertheless, there is little scientific production on the evolution of this breed and there are no studies on the morphometric transformations that took place during its formation. In this context, the present study aimed to assess the evolution in morphometric measures of the Mangalarga Marchador breed between 1970 and 2010. The research used information archived at the Brazilian Association of Mangalarga Marchador Breeders from 23,148 males and 92,980 females in a completely randomized experimental design. The six treatments consisted of the animals measured between 1970 and 1979, 1980 and 1989, 1990 and 1994, 1995 and 1999, 2000 and 2004, and 2005 and 2010, respectively. The measures assessed were: height at withers and croup, length of the head, neck, back, croup, shoulder, and body, width of the head and croup, thoracic circumference, and cannon circumference Over the period analyzed, males and females experienced a reduction in thoracic circumference, in the lengths of the head, back, croup, and shoulder, and in the widths of the head and croup. In the males, neck length and cannon circumference also decreased, while body length increased in females. Over time, breed selection led to smaller head, higher stature, and shorter trunk length. However, important measures for the breed’s functionality, such as shoulder length and thoracic circumference, decreased.

Characteristics of Female Solo and Female Co-Offenders and Male Solo Sexual Offenders Against Children.

Science.gov (United States)

Williams, Rebecca; Gillespie, Steven M; Elliott, Ian A; Eldridge, Hilary J

2017-09-01

Studies have highlighted differences in the victim choice, offender, and offense characteristics of female and male sexual offenders. However, little is known about how solo and co-offending females differ from solo male sexual offenders. We compared the characteristics of 20 solo and 20 co-offending females (co-offended with a male and/or female accomplice), and 40 male sexual offenders against children. We found that solo female offenders showed the most evidence of personal problems, including depression and sexual dissatisfaction. Compared with male offenders, female co-offenders showed poorer self-management, but better sexual self-regulation. Male offenders had a greater history of offending and showed more evidence of sexual abuse supportive cognitions relative to both solo and co-offending females. These results are consistent with the need for a gender-specific approach to working with sexual offenders and may have implications for understanding the often complex treatment needs of these clients.

The Lumbar Lordosis in Males and Females, Revisited.

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Ori Hay

Full Text Available Whether differences exist in male and female lumbar lordosis has been debated by researchers who are divided as to the nature of variations in the spinal curve, their origin, reasoning, and implications from a morphological, functional and evolutionary perspective. Evaluation of the spinal curvature is constructive in understanding the evolution of the spine, as well as its pathology, planning of surgical procedures, monitoring its progression and treatment of spinal deformities. The aim of the current study was to revisit the nature of lumbar curve in males and females.Our new automated method uses CT imaging of the spine to measure lumbar curvature in males and females. The curves extracted from 158 individuals were based on the spinal canal, thus avoiding traditional pitfalls of using bone features for curve estimation. The model analysis was carried out on the entire curve, whereby both local and global descriptors were examined in a single framework. Six parameters were calculated: segment length, curve length, curvedness, lordosis peak location, lordosis cranial peak height, and lordosis caudal peak height.Compared to males, the female spine manifested a statistically significant greater curvature, a caudally located lordotic peak, and greater cranial peak height. As caudal peak height is similar for males and females, the illusion of deeper lordosis among females is due partially to the fact that the upper part of the female lumbar curve is positioned more dorsally (more backwardly inclined.Males and females manifest different lumbar curve shape, yet similar amount of inward curving (lordosis. The morphological characteristics of the female spine were probably developed to reduce stress on the vertebral elements during pregnancy and nursing.

The Lumbar Lordosis in Males and Females, Revisited.

Science.gov (United States)

Hay, Ori; Dar, Gali; Abbas, Janan; Stein, Dan; May, Hila; Masharawi, Youssef; Peled, Nathan; Hershkovitz, Israel

2015-01-01

Whether differences exist in male and female lumbar lordosis has been debated by researchers who are divided as to the nature of variations in the spinal curve, their origin, reasoning, and implications from a morphological, functional and evolutionary perspective. Evaluation of the spinal curvature is constructive in understanding the evolution of the spine, as well as its pathology, planning of surgical procedures, monitoring its progression and treatment of spinal deformities. The aim of the current study was to revisit the nature of lumbar curve in males and females. Our new automated method uses CT imaging of the spine to measure lumbar curvature in males and females. The curves extracted from 158 individuals were based on the spinal canal, thus avoiding traditional pitfalls of using bone features for curve estimation. The model analysis was carried out on the entire curve, whereby both local and global descriptors were examined in a single framework. Six parameters were calculated: segment length, curve length, curvedness, lordosis peak location, lordosis cranial peak height, and lordosis caudal peak height. Compared to males, the female spine manifested a statistically significant greater curvature, a caudally located lordotic peak, and greater cranial peak height. As caudal peak height is similar for males and females, the illusion of deeper lordosis among females is due partially to the fact that the upper part of the female lumbar curve is positioned more dorsally (more backwardly inclined). Males and females manifest different lumbar curve shape, yet similar amount of inward curving (lordosis). The morphological characteristics of the female spine were probably developed to reduce stress on the vertebral elements during pregnancy and nursing.

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.

Dating violence among male and female youth seeking emergency department care.

Science.gov (United States)

Singh, Vijay; Walton, Maureen A; Whiteside, Lauren K; Stoddard, Sarah; Epstein-Ngo, Quyen; Chermack, Stephen T; Cunningham, Rebecca M

2014-10-01

We determine prevalence and correlates of dating violence, dating victimization, and dating aggression among male and female patients aged 14 to 20 years seeking emergency department (ED) care. This was a systematic sampling of subjects aged 14 to 20 years seeking care at a single large academic ED between September 2010 and March 2013. Participants completed a computerized, self-administered, cross-sectional survey of demographics, dating violence from physical abuse measures of the Conflict in Adolescent Dating Relationships Inventory, associated behaviors, and ED health service use. Separate analyses were conducted for male and female patients. Four thousand three hundred eighty-nine youths (86.1% participation rate) were screened, and 4,089 (mean age 17.5 years; 58% female patients) were eligible for analysis. Almost 1 in 5 female patients (n=215; 18.4%) and 1 in 8 male patients (n=212; 12.5%) reported past-year dating violence. Of female patients, 10.6% reported dating victimization and 14.6% dating aggression, whereas of male patients, 11.7% reported dating victimization and 4.9% reported dating aggression. Multivariate analyses showed that variables associated with any male dating violence were black race (adjusted odds ratio [AOR] 2.26; 95% CI 1.54 to 3.32), alcohol misuse (AOR 1.03; 95% CI 1.00 to 1.06), illicit drug use (AOR 2.38; 95% CI 1.68 to 3.38), and depression (AOR 2.13; 95% CI 1.46 to 3.10); any female dating violence was associated with black race (AOR 1.68; 95% CI 1.25 to 2.25), public assistance (AOR 1.64; 95% CI 1.28 to 2.09), grades D and below (AOR 1.62; 95% CI 1.07 to 2.43), alcohol misuse (AOR 1.04; 95% CI 1.02 to 1.07), illicit drug use (AOR 2.85; 95% CI 2.22 to 3.66), depression (AOR 1.86; 95% CI 1.42 to 2.44), and any past year ED visit for intentional injury (AOR 2.64; 95% CI 1.30 to 5.40). Nearly 1 of 6 male and female patients aged 14 to 20 years and seeking ED care report recent dating violence, and health disparities remain among

Bacterial vaginosis associated with increased risk of female-to-male HIV-1 transmission: a prospective cohort analysis among African couples.

Directory of Open Access Journals (Sweden)

Craig R Cohen

Full Text Available Bacterial vaginosis (BV, a disruption of the normal vaginal flora, has been associated with a 60% increased risk of HIV-1 acquisition in women and higher concentration of HIV-1 RNA in the genital tract of HIV-1-infected women. However, whether BV, which is present in up to half of African HIV-1-infected women, is associated with an increase in HIV-1 transmission to male partners has not been assessed in previous studies.We assessed the association between BV on female-to-male HIV-1 transmission risk in a prospective study of 2,236 HIV-1-seropositive women and their HIV-1 uninfected male partners from seven African countries from a randomized placebo-controlled trial that enrolled heterosexual African adults who were seropositive for both HIV-1 and herpes simplex virus (HSV-2, and their HIV-1-seronegative partners. Participants were followed for up to 24 months; every three months, vaginal swabs were obtained from female partners for Gram stain and male partners were tested for HIV-1. BV and normal vaginal flora were defined as a Nugent score of 7-10 and 0-3, respectively. To reduce misclassification, HIV-1 sequence analysis of viruses from seroconverters and their partners was performed to determine linkage of HIV-1 transmissions. Overall, 50 incident HIV-1 infections occurred in men in which the HIV-1-infected female partner had an evaluable vaginal Gram stain. HIV-1 incidence in men whose HIV-1-infected female partners had BV was 2.91 versus 0.76 per 100 person-years in men whose female partners had normal vaginal flora (hazard ratio 3.62, 95% CI 1.74-7.52. After controlling for sociodemographic factors, sexual behavior, male circumcision, sexually transmitted infections, pregnancy, and plasma HIV-1 RNA levels in female partners, BV was associated with a greater than 3-fold increased risk of female-to-male HIV-1 transmission (adjusted hazard ratio 3.17, 95% CI 1.37-7.33.This study identified an association between BV and increased risk of HIV

Association of Blood Transfusion From Female Donors With and Without a History of Pregnancy With Mortality Among Male and Female Transfusion Recipients.

Science.gov (United States)

Caram-Deelder, Camila; Kreuger, Aukje L; Evers, Dorothea; de Vooght, Karen M K; van de Kerkhof, Daan; Visser, Otto; Péquériaux, Nathalie C V; Hudig, Francisca; Zwaginga, Jaap Jan; van der Bom, Johanna G; Middelburg, Rutger A

2017-10-17

Transfusion of red blood cells from female donors has been associated with increased mortality in male recipients. To quantify the association between red blood cell transfusion from female donors with and without a history of pregnancy and mortality of red blood cell recipients. Retrospective cohort study of first-time transfusion recipients at 6 major Dutch hospitals enrolled from May 30, 2005, to September 1, 2015; the final follow-up date was September 1, 2015. The primary analysis was the no-donor-mixture cohort (ie, either all red blood cell transfusions exclusively from male donors, or all exclusively from female donors without a history of pregnancy, or all exclusively from female donors with a history of pregnancy). The association between mortality and exposure to transfusions from ever-pregnant or never-pregnant female donors was analyzed using life tables and time-varying Cox proportional hazards models. Red blood cell transfusions from ever-pregnant or never-pregnant female donors, compared with red blood cell transfusions from male donors. All-cause mortality during follow-up. The cohort for the primary analyses consisted of 31 118 patients (median age, 65 [interquartile range, 42-77] years; 52% female) who received 59 320 red blood cell transfusions exclusively from 1 of 3 types of donors (88% male; 6% ever-pregnant female; and 6% never-pregnant female). The number of deaths in this cohort was 3969 (13% mortality). For male recipients of red blood cell transfusions, all-cause mortality rates after a red blood cell transfusion from an ever-pregnant female donor vs male donor were 101 vs 80 deaths per 1000 person-years (time-dependent "per transfusion" hazard ratio [HR] for death, 1.13 [95% CI, 1.01-1.26]). For receipt of transfusion from a never-pregnant female donor vs male donor, mortality rates were 78 vs 80 deaths per 1000 person-years (HR, 0.93 [95% CI, 0.81-1.06]). Among female recipients of red blood cell transfusions, mortality rates for

FUNCTIONAL MALE STERILITY AND ITS USE IN BREEDING OF VEGETABLE AND MELON CROPS

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A. N. Bocharnikov

2014-01-01

Full Text Available The article describes the manifestation of functional male sterility and its importance in the breeding of melons. Utilization of functional male sterility allows solving the problem effective hybrid seed production.

Bibliography. Examples of literature related to the use of induced mutations in cross-breeding

International Nuclear Information System (INIS)

Micke, A.

1976-01-01

The bibliography contains about 400 references arranged alphabetically under the following 20 headings: Genetic analysis of mutants; Mutant gene combination and interaction; Pleiotropy versus linkage; Genetic background; Heterosis and overdominance; Mutations in heterozygous plants such as vegetatively propagated plants; Mutations in hybrids of self-pollinators; Distant hybridization; Increasing recombination; Alteration in the reproductive system; Alteration of photoperiodic response; Self and cross-incompatibility; Male or female sterility; Adaptability of mutants and mutant hybrids; Mutation induction in cross pollinators; Dwarfing mutant genes in cross-breeding; Protein mutants in cross-breeding; Disease resistant mutants in cross-breeding; Practical cross-breeding programmes using mutants; Spontaneous versus induced genetic diversity

Corticosterone mediated costs of reproduction link current to future breeding.

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Crossin, Glenn T; Phillips, Richard A; Lattin, Christine R; Romero, L Michael; Williams, Tony D

2013-11-01

Life-history theory predicts that costs are associated with reproduction. One possible mediator of costs involves the secretion of glucocorticoid hormones, which in birds can be measured in feathers grown during the breeding period. Glucocorticoids mediate physiological responses to unpredictable environmental or other stressors, but they can also function as metabolic regulators during more predictable events such as reproduction. Here we show that corticosterone ("Cort") in feathers grown during the breeding season reflects reproductive effort in two Antarctic seabird species (giant petrels, Macronectes spp.). In females of both species, but not males, feather Cort ("fCort") was nearly 1.5-fold higher in successful than failed breeders (those that lost their eggs/chicks), suggesting a cost of successful reproduction, i.e., high fCort levels in females reflect the elevated plasma Cort levels required to support high metabolic demands of chick-rearing. Successful breeding also led to delayed moult prior to winter migration. The fCort levels and pre-migration moult score that we measured at the end of current breeding were predictive of subsequent reproductive effort in the following year. Birds with high fCort and a delayed initiation of moult were much more likely to defer breeding in the following year. Cort levels and the timing of moult thus provide a potential mechanism for the tradeoff between current and future reproduction. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

Metabolic and affective consequences of fatherhood in male California mice.

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Zhao, Meng; Garland, Theodore; Chappell, Mark A; Andrew, Jacob R; Saltzman, Wendy

2017-08-01

Physiological and affective condition can be modulated by the social environment and parental state in mammals. However, in species in which males assist with rearing offspring, the metabolic and affective effects of pair bonding and fatherhood on males have rarely been explored. In this study we tested the hypothesis that fathers, like mothers, experience energetic costs as well as behavioral and affective changes (e.g., depression, anxiety) associated with parenthood. We tested this hypothesis in the monogamous, biparental California mouse (Peromyscus californicus). Food intake, blood glucose and lipid levels, blood insulin and leptin levels, body composition, pain sensitivity, and depression-like behavior were compared in males from three reproductive groups: virgin males (VM, housed with another male), non-breeding males (NB, housed with a tubally ligated female), and breeding males (BM, housed with a female and their first litter). We found statistically significant (Pfatherhood influences several metabolic, morphological, and affective measures in male California mice. Overall, the changes we observed in breeding males were minor, but stronger effects might occur in long-term breeding males and/or under more challenging environmental conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

Hello handsome! Male's facial attractiveness gives rise to female's fairness bias in Ultimatum Game scenarios-An ERP study.

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Ma, Qingguo; Qian, Da; Hu, Linfeng; Wang, Lei

2017-01-01

The current study delineated how male proposers' facial attractiveness affect female responders' fairness considerations and their subsequent decision outcome during the Ultimatum Game (UG). Event Related Potentials (ERPs) were recorded from 17 female subjects, who played the role as responders and had to decide whether to accept offers from either attractive or unattractive male proposers. Behavioral data (Acceptance Ratio and Response time) revealed that, more offers were accepted from attractive-face conditions; subjects typically responded quicker to unfair offers from unattractive proposers as compared with slower to unfair offers from attractive proposers. The ERP data demonstrated similar N2 amplitudes elicited by both attractive and unattractive faces, and a larger early frontal LPP elicited by the attractive faces compared with unattractive ones, but no significant differences of both late posterior LPP and typical parietal LPP amplitudes were observed between these two face conditions, which was different from our previous study with similar paradigm but male participants. The results suggest that, in comparison to males, females might not experience the potential attention bias towards unattractive opposite-sex faces and are less likely to possess an enhanced processing and evaluation of those faces. This phenomenon might be explained by endogenous gender differences in mate preference. The feedback-related negativity (FRN) and P300 responses during an offer presentation were further measured in both attractive-face and unattractive-face conditions and the results demonstrated that the amplitudes elicited by fair and unfair offers were not statistically different in the former condition, but were different in the latter condition. More specifically, unfair offers generated larger FRN and smaller P300 than fair ones in the unattractive-face condition. Findings suggest that, although females tend to possess less salient evaluation of male's facial

Female social response to male sexual harassment in poeciliid fish: a comparison of six species

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Dadda, Marco

2015-01-01

Sexual harassment is common among poeciliid fish. In some fishes, males show a high frequency of sneak copulation; such sexual activity is costly to the females in terms of foraging efficiency. In mosquitofish (Gambusia holbrooki), when males are present, the distance between females tends to decrease, and this behavior has been interpreted as an adaptive strategy to dilute the costs of male sexual activity. In this study, the tendency to reduce distance in the presence of a male has been investigated in females of six poeciliid species (Girardinus metallicus, Girardinus falcatus, G. holbrooki, Poecilia reticulata, Xiphophorus hellerii, and Xiphophorus mayae) that exhibit different male mating strategies and different levels of sexual activity. Results revealed large interspecific differences in the pattern of female aggregation. Females of species with a high frequency of sneak copulations tended to reduce their social distance in the presence of a male. By contrast, species that rely mainly on courtship showed little or no variation in social distance. The proportion of sneak copulations predicts the degree of variation in female social response, but the amount of total sexual activity does not, suggesting that the change in females' social distance when a male is present may indeed serve to reduce the costs of male sexual harassment. PMID:26483719

Female social response to male sexual harassment in poeciliid fish: a comparison of six species.

Science.gov (United States)

Dadda, Marco

2015-01-01

Sexual harassment is common among poeciliid fish. In some fishes, males show a high frequency of sneak copulation; such sexual activity is costly to the females in terms of foraging efficiency. In mosquitofish (Gambusia holbrooki), when males are present, the distance between females tends to decrease, and this behavior has been interpreted as an adaptive strategy to dilute the costs of male sexual activity. In this study, the tendency to reduce distance in the presence of a male has been investigated in females of six poeciliid species (Girardinus metallicus, Girardinus falcatus, G. holbrooki, Poecilia reticulata, Xiphophorus hellerii, and Xiphophorus mayae) that exhibit different male mating strategies and different levels of sexual activity. Results revealed large interspecific differences in the pattern of female aggregation. Females of species with a high frequency of sneak copulations tended to reduce their social distance in the presence of a male. By contrast, species that rely mainly on courtship showed little or no variation in social distance. The proportion of sneak copulations predicts the degree of variation in female social response, but the amount of total sexual activity does not, suggesting that the change in females' social distance when a male is present may indeed serve to reduce the costs of male sexual harassment.

Attitudes to female genital mutilation/cutting among male adolescents in Ilorin, Nigeria.

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Adeniran, Abiodun S; Ijaiya, Munirdeen A; Fawole, Adegboyega A; Balogun, Olayinka R; Adesina, Kikelomo T; Olatinwo, Abdul Waheed O; Olarinoye, Adebunmi O; Adeniran, Peace I

2016-07-04

The central role of males in female reproductive health issues in patriarchal societies makes them an important group in the eradication of female genital mutilation/cutting (FGM/C). To determine knowledge about and attitudes to FGM/C among male adolescents, and their preparedness to protect their future daughters from it. A cross-sectional survey among male adolescent students in Ilorin, Nigeria. Participants completed a self-administered questionnaire after consent had been obtained from them or their parents. Statistical analysis was with SPSS version 20.0 (IBM, USA). A p-value of <0.05 was taken as significant. Of 1 536 male adolescents (mean age 15.09 (standard deviation 1.84) years, range 14 - 19), 1 184 (77.1%) were aware of FGM/C, 514 (33.5%) supported female circumcision, 362 (23.6%) would circumcise their future daughters, 420 (27.3%) were of the opinion that FGM/C had benefits, mostly as a necessity for womanhood (109, 7.1%), and 627 (40.8%) perceived it as wickedness against females; 546 (35.5%) were aware of efforts to eradicate FGM/C, and 42.2% recommended education as the most important intervention to achieve this. Education and involvement in advocacy may transform male adolescents into agents for eradication of FGM/C.

No evidence for female discrimination against male house mice carrying a selfish genetic element.

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Sutter, Andreas; Lindholm, Anna K

2016-12-01

Meiotic drivers distort transmission to the next generation in their favor, with detrimental effects on the fitness of their homologues and the rest of the genome. Male carriers of meiotic drivers commonly inflict costs on their mates through genetic incompatibility, reduced fecundity, or biased brood sex ratios. Given these costs, evidence for female discrimination against male carriers is surprisingly rare. One of few examples is the t haplotype in house mice, a meiotic driver that shows strong transmission distortion in males and is typically homozygote lethal. As a consequence, mating between 2 t heterozygous (+/ t ) mice leads to high embryo mortality. Previous experiments showing that +/ t females avoid this incompatibility cost by preferring +/+ versus +/ t males have inferred preference based on olfactory cues or brief social interactions. Evidence from mating contexts in laboratory settings and semi-natural populations has been inconclusive. Here, we investigated female choice from a large number of no-choice mating trials. We found no evidence for discrimination against +/ t males based on mating, remating, and copulatory behavior. Further, we found no evidence for avoidance of incompatibility through selective interactions between gametes. The likelihood of mating showed significant effects of female weight and genotype, suggesting that our test paradigm enabled females to exhibit mate choice. We discuss the strengths and limitations of our approach. By explicitly considering selection at both the individual and gene level, we argue why precopulatory female discrimination by +/ t females may be less evolutionarily stable than discrimination by all females based on postcopulatory mechanisms.

Sexy males and choosy females on exploded leks: correlates of male attractiveness in the Little Bustard.

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Jiguet, Frédéric; Bretagnolle, Vincent

2014-03-01

In their choice of mates, females may use alternative tactics, including a comparative assessment of males in a population, using one or several relative preference criteria. Traits involved in female choice should presumably be variable between, but not within males, thus potentially providing reliable cues of male identity and quality for prospecting females. In lekking species, sexual selection is usually intense, and females can freely choose mates. Studying the Little Bustard Tetrax tetrax, a bird with an exploded lek mating system, we first identified male phenotypic traits that showed higher among, than within variation (plumage pattern, display rates and call structure). Among those and other traits (ornaments and their symmetry, body condition, lek spatial organization and territory quality), we identified phenotypic traits that correlated with male attractiveness toward females. At least four phenotypic male traits were correlated with female attraction, i.e. body condition, lek attendance, ornamental symmetry and display rates. Traits related to the initial female attraction on male territory seem to differ from traits related to the decision of females to stay in the territory of attractive males. Copyright © 2014 Elsevier B.V. All rights reserved.

Female perception of male body odor.

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Sergeant, Mark J T

2010-01-01

Olfaction is one of the most crucial forms of communication among nonhuman animals. Historically, olfaction has been perceived as being of limited importance for humans, but recent research has documented that not only do humans have sensitive olfactory abilities, but also odors have the potential to influence our physiology and behavior. This chapter reviews research on olfactory communication among humans, focusing on the effects of male bodily odors on female physiology and behavior. The process of body odor production and the detection of olfactory signals are reviewed, focusing on potential sex differences in these abilities. The effects of male body odors on female physiological and behavioral effects of body odors are considered. Finally, with specific regard to female mate choice, evidence regarding the influence of the major histocompatibility complex and fluctuating asymmetry on male olfactory cues is reviewed. Copyright © 2010 Elsevier Inc. All rights reserved.

Robotic crabs reveal that female fiddler crabs are sensitive to changes in male display rate.

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Mowles, Sophie L; Jennions, Michael D; Backwell, Patricia R Y

2018-01-01

Males often produce dynamic, repetitive courtship displays that can be demanding to perform and might advertise male quality to females. A key feature of demanding displays is that they can change in intensity: escalating as a male increases his signalling effort, but de-escalating as a signaller becomes fatigued. Here, we investigated whether female fiddler crabs, Uca mjoebergi , are sensitive to changes in male courtship wave rate. We performed playback experiments using robotic male crabs that had the same mean wave rate, but either escalated, de-escalated or remained constant. Females demonstrated a strong preference for escalating robots, but showed mixed responses to robots that de-escalated ('fast' to 'slow') compared to those that waved at a constant 'medium' rate. These findings demonstrate that females can discern changes in male display rate, and prefer males that escalate, but that females are also sensitive to past display rates indicative of prior vigour. © 2018 The Authors.

The influence of male takeovers on female dispersal in Colobus vellerosus.

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Sicotte, Pascale; Teichroeb, Julie A; Vayro, Josie V; Fox, Stephanie A; Bădescu, Iulia; Wikberg, Eva C

2017-07-01

Male takeovers affect male tenure, female mate choice and ultimately, individual reproductive success in group-living primates. In social systems with female philopatry and high male reproductive skew, male takeovers largely determine female mate choice, whereas in species with female dispersal, females have the option of deserting a new male. We focused on a species with facultative female dispersal to investigate which factors promote female desertion of males after takeover, using 15 cases (12 for which we have complete data on the takeover process and the female dispersal outcome). These cases took place in nine groups of Colobus vellerosus between 2001 and 2013 at the Boabeng-Fiema Monkey Sanctuary, Ghana. Quick takeovers were usually achieved by single adult males and were never followed by female dispersal. Slow takeovers involved several males, and these takeovers were regularly accompanied by female emigration. Infant attacks and infanticide by males occurred during both kinds of takeovers, but females with dependent offspring never dispersed, regardless of whether their infant was attacked or killed by the new male(s). Subadult females, who were not constrained by the presence of infants, dispersed more often after slow takeovers than after quick takeovers. Whether female dispersal post-takeover is an expression of female mate choice, or occurs to avoid the social upheaval surrounding slow takeovers, remains to be investigated. Am. J. Primatol. 79:e22436, 2017. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Social Responsibility Personality Differences between Male and Female Communicators.

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Hantz, Alan M.; Wright, Donald K.

A study was conducted to explore in what ways, if any, male public relations practitioners differ from their female counterparts in their level of social responsibility. Subjects were 105 public relations practitioners (60% female and 40% male) and 215 college students (71% female and 29% male), who completed the Berkowitz-Lutterman SRS Scale. The…

How female and male physicians' communication is perceived differently.

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Mast, Marianne Schmid; Kadji, Keou Kambiwa

2018-06-07

This paper is based on a 2017 Baltimore International Conference on Communication in Healthcare (ICCH) plenary presentation by the first author and addresses how female and male physicians' communication is perceived and evaluated differently. Female physicians use patient-centered communication which is the interaction style clearly preferred by patients. Logically, patients should be much more satisfied with female than male physicians. However, research shows that this is not the case. This article provides an overview on how female and male physician communication is evaluated and perceived differently by patients and discusses whether and how gender stereotypes can explain these differences in perception and evaluation. Male physicians obtain good patient outcomes when verbally expressing patient-centeredness while female physicians have patients who report better outcomes when they adapt their nonverbal communication to the different needs of their patients. The analysis reveals that existing empirical findings cannot simply be explained by the adherence or not to gender stereotypes. Female physicians do not always get credit for showing gender role congruent behavior. All in all, female and male physicians do not obtain credit for the same behaviors. Physician communication training might put different accents for female and male physicians. Copyright © 2018 Elsevier B.V. All rights reserved.

Potential for the use of male pheromone components in female trapping: a progress report

International Nuclear Information System (INIS)

Howse, P.E.; Underwood, K.L.; Knapp, J.J.; Alemany Ferra, A.; Miranda, M.A.

1999-01-01

Experiments were conducted to determine if reducing the male population using TML traps and pheromone baited traps would enhance female Mediterranean fruit fly capture. Investigations were conducted in citrus plantations in Mallorca. In the first trial (0.36 ha, Son Coll Vey, Palma) Agrisense yellow delta traps were deployed on every third tree in adjacent rows. On each other tree, a TML bait was placed with an insecticide strip containing Dichlorvos. Thus, each of the delta traps was surrounded by a hexagon of TML + insecticide baited trees. The rationale of this experiment was to remove males from the vicinity of pheromone-baited traps and thereby increase the apparency of the female lure. Before the trial, male catches averaged 4.1 per day in TML traps. During the trial, this was reduced to approximately 0.6 males/trap/day. The traps with pheromone (pyrazines in various combinations and ratios) caught around 0.05 females/trap/day. The pheromone traps remained female selective, with a negligible male catch, similar to that in unbaited traps. The most likely cause for the very low female catch may be that insufficient males were removed by the lure and kill devices. In the second trial (0.67 ha, Inca, Mallorca) the proprietor had deployed 83 traps, baited with TML and insecticide, for 18 days prior to the placement of five treatments with six replicates. The delta traps were placed on every third tree, with replicates every third row. The female catch showed a progressive enhancement over a period of 6 weeks, reaching a level about six times that of males in TML traps. (author)

Social polyandry, parental investment, sexual selection, and evolution of reduced female gamete size.

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Andersson, Malte

2004-01-01

Sexual selection in the form of sperm competition is a major explanation for small size of male gametes. Can sexual selection in polyandrous species with reversed sex roles also lead to reduced female gamete size? Comparative studies show that egg size in birds tends to decrease as a lineage evolves social polyandry. Here, a quantitative genetic model predicts that female scrambles over mates lead to evolution of reduced female gamete size. Increased female mating success drives the evolution of smaller eggs, which take less time to produce, until balanced by lowered offspring survival. Mean egg size is usually reduced and polyandry increased by increasing sex ratio (male bias) and maximum possible number of mates. Polyandry also increases with the asynchrony (variance) in female breeding start. Opportunity for sexual selection increases with the maximum number of mates but decreases with increasing sex ratio. It is well known that parental investment can affect sexual selection. The model suggests that the influence is mutual: owing to a coevolutionary feedback loop, sexual selection in females also shapes initial parental investment by reducing egg size. Feedback between sexual selection and parental investment may be common.

Attractive males have faster sperm in three-spined sticklebacks Gasterosteus aculeatus

Directory of Open Access Journals (Sweden)

Marion MEHLIS, Lukas K. HILKE, Theo C. M. BAKKER

2013-12-01

Full Text Available Recent studies have revealed that sexually selected traits may signal sperm quality and hence male fertilisation ability. There is also evidence that the expression of male sexual ornamentation and associated sperm characteristics depend on an individual’s ability to cope with oxidative stress. Carotenoids are known for their antioxidant properties and carotenoid-based ornaments might represent honest signals as these pigments can be traded off between the investment in sexual ornamentation, sperm function as well as immune response. In this study, we examined the relationship between sexual ornamentation (breeding coloration and sperm characteristics (e.g., velocity and morphology in the three-spined stickleback Gasterosteus aculeatus, an externally fertilising fish species, in which sperm competition commonly occurs. During the breeding season males are sperm limited and develop a conspicuous carotenoid-based coloration, which is under strong pre-copulatory sexual selection due to female mate choice and male-male competition. The results of the present study show that the expression of stickleback male breeding coloration is significantly positively associated with the linearity of sperm movement, whereas sperm morphology (head length to tail length ratio is significantly negatively related to the trajectory of sperm movement. Moreover, there is some support for the phenotype-linked fertility hypothesis as the intensity of male red breeding coloration is significantly positively correlated with sperm velocity, which is supposed to be an important determinant of fertilisation success in external fertilisers, indicating the honesty of the sexually selected nuptial red coloration [Current Zoology 59 (6: 761-768, 2013].

King eider foraging effort during the pre-breeding period in Alaska

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Oppel, Steffen; Powell, Abby N.; Butler, Malcolm G.

2011-01-01

For reproduction, many arctic-nesting migratory birds rely on nutrients obtained on the breeding grounds, so they devote sufficient time to foraging immediately prior to nesting. However, little is known about the increase in foraging effort necessary to meet the energetic requirements of reproduction. In early June 2006 and 2008, we quantified the proportion of time spent foraging before breeding by a large sea duck, the King Eider (Somateria spectabilis), on its breeding grounds in northern Alaska. During >235 hours of behavioral observations, both male and female King Eiders spent >50% of the day loafing (resting, sleeping, comfort behavior, or being alert). Females foraged on average 30% of the time (mean 7.2 hr day-1,95% CI 6.0-8.4 hr day-1), three times as much as males (9%; 2.3 hr day-1, 95% CI 1.5–2.8 hr day-1). The most common prey in ponds where the eiders foraged were chironomid larvae and worms ranging in length from 1 to 30 mm. If the King Eider's daily energy expenditure on its breeding grounds is similar to values published for related species, it would need to ingest only 0.2–0.6 g dry mass of invertebrates per minute of foraging to meet its energetic requirements. Males did not lose body mass before breeding, and we assume that their foraging effort was sufficient for energy balance. Therefore, female King Eiders appear to triple their foraging effort over maintenance requirements to meet the energetic challenges of egg formation.

Field Investigation on the Prevalence of Trypanosomiasis in Camels in Relation to Sex, Age, Breed and Herd Size

Directory of Open Access Journals (Sweden)

B. Bhutto, J. A. Gadahi, G. Shah1, P. Dewani2 and A.G. Arijo

2010-07-01

Full Text Available Blood samples were collected from 240 camels (183 male and 57 female of four breeds from six districts of Sindh. An overall infection was determined as 11.25%. Species of Trypanosoma was identified as Trypanosoma evansi. District wise infection was found to be 2.5, 7.5, 12.5, 15.00, 22.5 and 7.5% in Hyderabad, Mirpur Khas, Umerkot, Badin, Thatta and Larkana, respectively. A higher infection was found in females (15.79% as compared to males (9.84%. Highest (14.96% infection was noted in age group >7 years, followed by 8.57 and 4.65% in 3 to 7 years and less than to 3 years old camels, respectively. Four breeds of camels were surveyed and the highest infection rate was found in Sakrai breed (21.82%, followed by 16.67, 6.15 and 5.95% in Kharai, Sindhi and Dhati breeds respectively. When herd size was considered, infection rate was 1.67, 6.67, 15.00 and 21.67% in herds possessing 1 to 5, 6 to 10, 11 to 20 and more than 20 animals, respectively.

Differences in peripheral sensory input to the olfactory bulb between male and female mice

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Kass, Marley D.; Czarnecki, Lindsey A.; Moberly, Andrew H.; McGann, John P.

2017-04-01

Female mammals generally have a superior sense of smell than males, but the biological basis of this difference is unknown. Here, we demonstrate sexually dimorphic neural coding of odorants by olfactory sensory neurons (OSNs), primary sensory neurons that physically contact odor molecules in the nose and provide the initial sensory input to the brain’s olfactory bulb. We performed in vivo optical neurophysiology to visualize odorant-evoked OSN synaptic output into olfactory bub glomeruli in unmanipulated (gonad-intact) adult mice from both sexes, and found that in females odorant presentation evoked more rapid OSN signaling over a broader range of OSNs than in males. These spatiotemporal differences enhanced the contrast between the neural representations of chemically related odorants in females compared to males during stimulus presentation. Removing circulating sex hormones makes these signals slower and less discriminable in females, while in males they become faster and more discriminable, suggesting opposite roles for gonadal hormones in influencing male and female olfactory function. These results demonstrate that the famous sex difference in olfactory abilities likely originates in the primary sensory neurons, and suggest that hormonal modulation of the peripheral olfactory system could underlie differences in how males and females experience the olfactory world.

The involvement of prolactin in avian molt: the effects of gender and breeding success on the timing of molt in Mute swans (Cygnus olor).

Science.gov (United States)

Dawson, A; Perrins, C M; Sharp, P J; Wheeler, D; Groves, S

2009-04-01

The aim of the study was to test the hypothesis that decreasing plasma prolactin stimulates or permits the initiation of avian molt. Changes in the concentration of plasma prolactin in Mute swans (Cygnus olor) were compared in non-breeding singletons and breeding pairs. In breeding swans, the onset of molt is delayed compared to non-breeders, and is delayed further in breeding males compared to their female partners. The seasonal decrease in prolactin in non-breeding birds of both sexes started at the end of May and was associated with the initiation of molt 4 weeks later. The decrease in plasma prolactin in incubating females was more pronounced, as a consequence of increased prolactin secretion associated with incubation behavior, but also started at end of May, and was associated the onset of molt 6 weeks later. In breeding males, plasma prolactin increased at the end of May when they started to care for their newly hatched cygnets. Correspondingly, prolactin began to decrease 3-5 weeks later in males than in females. These males started to molt in mid August, at least 4 weeks later than females. It is concluded that molt is related to decreasing plasma prolactin, and is inhibited when plasma prolactin is increasing or high.

Association of Blood Transfusion From Female Donors With and Without a History of Pregnancy With Mortality Among Male and Female Transfusion Recipients

Science.gov (United States)

Caram-Deelder, Camila; Kreuger, Aukje L.; Evers, Dorothea; de Vooght, Karen M. K.; van de Kerkhof, Daan; Visser, Otto; Péquériaux, Nathalie C. V.; Hudig, Francisca; Zwaginga, Jaap Jan; van der Bom, Johanna G.

2017-01-01

Importance Transfusion of red blood cells from female donors has been associated with increased mortality in male recipients. Objective To quantify the association between red blood cell transfusion from female donors with and without a history of pregnancy and mortality of red blood cell recipients. Design, Setting, and Participants Retrospective cohort study of first-time transfusion recipients at 6 major Dutch hospitals enrolled from May 30, 2005, to September 1, 2015; the final follow-up date was September 1, 2015. The primary analysis was the no-donor-mixture cohort (ie, either all red blood cell transfusions exclusively from male donors, or all exclusively from female donors without a history of pregnancy, or all exclusively from female donors with a history of pregnancy). The association between mortality and exposure to transfusions from ever-pregnant or never-pregnant female donors was analyzed using life tables and time-varying Cox proportional hazards models. Exposures Red blood cell transfusions from ever-pregnant or never-pregnant female donors, compared with red blood cell transfusions from male donors. Main Outcomes and Measures All-cause mortality during follow-up. Results The cohort for the primary analyses consisted of 31 118 patients (median age, 65 [interquartile range, 42-77] years; 52% female) who received 59 320 red blood cell transfusions exclusively from 1 of 3 types of donors (88% male; 6% ever-pregnant female; and 6% never-pregnant female). The number of deaths in this cohort was 3969 (13% mortality). For male recipients of red blood cell transfusions, all-cause mortality rates after a red blood cell transfusion from an ever-pregnant female donor vs male donor were 101 vs 80 deaths per 1000 person-years (time-dependent “per transfusion” hazard ratio [HR] for death, 1.13 [95% CI, 1.01-1.26]). For receipt of transfusion from a never-pregnant female donor vs male donor, mortality rates were 78 vs 80 deaths per 1000 person-years (HR

Female social response to male sexual harassment in poeciliid fish: A comparison of six species

Directory of Open Access Journals (Sweden)

Marco eDadda

2015-09-01

Full Text Available Sexual harassment is common among poeciliid fish. In some fishes, males show a high frequency of sneak copulation; such sexual activity is costly to the females in terms of foraging efficiency. In mosquitofish (Gambusia holbrooki, when males are present, the distance between females tends to decrease, and this behavior has been interpreted as an adaptive strategy to dilute the costs of male sexual activity. In this study, the tendency to reduce distance in the presence of a male has been investigated in females of 6 poeciliid species (Girardinus metallicus, Girardinus falcatus, Gambusia holbrooki, Poecilia reticulata, Xiphophorus hellerii and Xiphophorus mayae that exhibit different male mating strategies and different levels of sexual activity. Results revealed large interspecific differences in the pattern of female aggregation. Females of species with a high frequency of sneak copulations tended to reduce their social distance in the presence of a male. By contrast, species that rely mainly on courtship showed little or no variation in social distance. The proportion of sneak copulations predicts the degree of variation in female social response, but the amount of total sexual activity does not, suggesting that the change in females’ social distance when a male is present may indeed serve to reduce the costs of male sexual harassment.

Perceptions of Credibility of Male and Female Syndicated Political Columnists.

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Andsager, Julie L.

1990-01-01

Examines perceptions of the credibility of male and female syndicated political columnists. Finds that college students exhibited little prejudice against female versus male bylines in political interpretive columns. Finds a small tendency for male readers to evaluate male bylines higher in stereotypical ways, but female readers do not do this.…

Effects of spring conditions on breeding propensity of Greater Snow Goose females

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Reed, E. T.

2004-06-01

Full Text Available Breeding propensity, defined as the probability that a sexually mature adult will breed in a given year, is an important determinant of annual productivity. It is also one of the least known demographic parameters in vertebrates. We studied the relationship between breeding propensity and conditions on spring staging areas (a spring conservation hunt and the breeding grounds (spring snow cover in Greater Snow Geese (Chen caerulescens atlantica, a long distance migrant that breeds in the High Arctic. We combined information from mark–recapture, telemetry, and nest survey data to estimate breeding propensity over a 7– year period. True temporal variation in breeding propensity was considerable (mean: 0.574 [95% CI considering only process variation: 0.13 to 1.0]. Spring snow cover was negatively related to breeding propensity (bsnow=-2,05 ± 0,96 SE and tended to be reduced in years with a spring hunt (b = -0,78 ± 0,35. Nest densities on the breeding colony and fall ratios of young:adults were good indices of annual variation in breeding propensity, with nest densities being slightly more precise. These results suggest that conditions encountered during the pre-breeding period can have a significant impact on productivity of Arctic-nesting birds

Female qualities in males: vitellogenin synthesis induced by ovary transplants into the male silkworm, Bombyx mori.

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Yang, Congwen; Lin, Ying; Shen, Guanwang; Chen, Enxiang; Wang, Yanxia; Luo, Juan; Zhang, Haiyan; Xing, Runmiao; Xia, Qingyou

2014-10-10

Female qualities in males are common in vertebrates but have not been extensively reported in insects. Vitellogenin (Vg) is highly expressed in the female fat body and is generally required for the formation of yolk proteins in the insect egg. Vg upregulation is generally regarded as a female quality in female oviparous animals. In this study, we found that Bombyx mori Vg (BmVg) is especially highly expressed in the female pupa. Downregulation of the BmVg gene in the female pupa by RNA interference (RNAi) interfered with egg formation and embryonic development, showing the importance of BmVg in these processes. So, we used BmVg as a biomarker for female qualities in the silkworm. Hematoxylin-eosin staining and immunofluorescence histochemistry showed that ovary transplants induced BmVg synthesis in the male pupa fat body. Ovaries transplanted into male silkworms produced only a few eggs with deformed yolk granules. These results suggested that the amount of BmVg in the male silkworm was insufficient for eggs to undergo complete embryonic development. After 17-beta-estradiol was used to treat male pupae and male pupal fat bodies, BmVg was upregulated in vivo and in vitro. These findings indicated that the male silkworm has innate female qualities that were induced by a transplanted ovary and 17β-estradiol. However, in silkworms, female qualities in males are not as complete as in females. Copyright © 2014 Elsevier Inc. All rights reserved.

The vibrational signals that male fiddler crabs ( Uca lactea) use to attract females into their burrows

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Takeshita, Fumio; Murai, Minoru

2016-06-01

In some fiddler crab species, males emit vibrations from their burrows to mate-searching females after they have attracted a female to the burrow entrance using a waving display. Although the vibrations are considered acoustic signals to induce mating, it has not been demonstrated whether the vibrations attract the females into the burrow and, consequently, influence females' mating decisions. We investigated the structures and patterns of the vibrations using a dummy female and demonstrated experimentally a female preference for male vibrations in Uca lactea in the field. The acoustic signals consisted of repetitions of pulses. The dominant frequency of the pulses decreased with male carapace width. The pulse length decreased slightly with an increasing number of vibrational repetitions, and the pulse interval increased with increasing repetitions. These factors imply that the vibrations convey information on male characteristics, such as body size and stamina. In the experiment on female mate choice, the females significantly preferred males with higher pulse repetition rates when they were positioned at the entrance of the burrow, indicating that the females use the male vibrational signals to decide whether to enter the burrow. However, females showed no preference for the vibrations once they were inside a burrow, i.e., whether they decided to copulate, suggesting that the vibrations do not independently affect a female's final decision of mate choice. The vibrations inside the burrow might influence a female's decision by interaction with other male traits such as the burrow structure.

Male foraging efficiency, but not male problem-solving performance, influences female mating preferences in zebra finches

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Véronique Chantal

2016-08-01

Full Text Available Experimental evidence suggests that females would prefer males with better cognitive abilities as mates. However, little is known about the traits reflecting enhanced cognitive skills on which females might base their mate-choice decisions. In particular, it has been suggested that male foraging performance could be used as an indicator of cognitive capacity, but convincing evidence for this hypothesis is still lacking. In the present study, we investigated whether female zebra finches (Taeniopygia guttata modify their mating preferences after having observed the performance of males on a problem-solving task. Specifically, we measured the females’ preferences between two males once before and once after an observation period, during which their initially preferred male was incapable of solving the task contrary to their initially less-preferred male. We also conducted a control treatment to test whether the shift in female preferences was attributable to differences between the two stimulus males in their foraging efficiency. Finally, we assessed each bird’s performance in a color associative task to check whether females can discriminate among males based on their learning speed. We found that females significantly increased their preference toward the most efficient male in both treatments. Yet, there was no difference between the two treatments and we found no evidence that females assess male cognitive ability indirectly via morphological traits. Thus, our results suggest that females would not use the males’ problem-solving performance as an indicator of general cognitive ability to gain indirect fitness benefits (i.e., good genes but rather to assess their foraging efficiency and gain direct benefits.

Male irradiation affects female remating behavior in Anastrepha serpentina (Diptera: Tephritidae).

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Landeta-Escamilla, Anais; Hernández, Emilio; Arredondo, José; Díaz-Fleischer, Francisco; Pérez-Staples, Diana

2016-02-01

Female remating in target pest species can affect the efficacy of control methods such as the Sterile Insect Technique (SIT) but very little is known about the postcopulatory mating behavior of these pests. In this study, we investigated the remating behavior of female Anastrepha serpentina (Diptera: Tephritidae), an oligophagous pest of Sapotaceae. First, we tested how long the sexual refractory period of females lasted after an initial mating. Second, we tested the effect of male and female sterility, female ovipositing opportunities and male density on female propensity to remate. Lastly, we tested if the amount of sperm stored by females was correlated to the likelihood of females to remate. We found that receptivity of mass-reared A. serpentina females had a bimodal response, with up to 16% of mass-reared A. serpentina females remating five days after the initial copulation, decreasing to 2% at 10 and 15 days and increasing to 13% after 20 days. Compared to fertile males, sterile males were less likely to mate and less likely to inhibit females from remating. Copula duration of sterile males was shorter compared to fertile males. Remating females were less likely to mate with a sterile male as a second mate. Sterile females were less likely to mate or remate compared to fertile females. Opportunity to oviposit and male density had no effect on female remating probability. Sperm numbers were not correlated with female likelihood to remate. Information on the post-copulatory behavior of mass-reared A. serpentina will aid fruit fly managers in improving the quality of sterile males. We discuss our results in terms of the differences this species presents in female remating behavior compared to other tephritids. Copyright © 2015 Elsevier Ltd. All rights reserved.

Tooth loss prevalence among cardiac males and females

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Bokhari, S.A.H.; Khan, A.A.; Butt, A.K.

2007-01-01

Objective of study was to observe differences of tooth loss prevalence in males and females with Cardiac diseases Poor oral health, tooth loss and periodontal diseases have been reported to be associated with coronary heart diseases. Studies report gender differences in prevalence of cardiac diseases and tooth loss. This paper presents gender differences of tooth loss in cardiac patients of a cardiac hospital of Lahore, Pakistan. Methodology: Age matched Cardiac males and females attending OPD of the Punjab Institute of Cardiology (PIC), Lahore were included in the study. Personal and health-related information were questioned and noted. Oral examination was performed for recording of missing teeth. 1200 CHD study subjects with age-range of 30 to 80 years were enrolled for study. 1045 age matched, 766 (73.30%) males and 279 (26.70%) females were examined for tooth loss. 852 (81.53%) genders had at least one tooth missing. 599 (78.19) males and 253 (90.68%) females were observed with mean tooth loss of 7.5 (SD 8.720) and 11.15 (SD 10.375)respectively statistical association among them was also significant (P= 0.000) with OR of 2.339. More subjects (76.29%) showed a loss of 1-15 teeth that I was also significant among males and females. Tooth loss was significant in age groups of 41-50 years (P=0.001) and 51-60 years (P=0.000) Gender differences of tooth loss prevalence among CHD Subjects were significant with more risk for males as compared to females. (author)

Environmental and hormonal factors in seasonal breeding in free-living male Indian rose-ringed parakeets (Psittacula krameri).

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Krishnaprasadan, T N; Kotak, V C; Sharp, P J; Schmedemann, R; Haase, E

1988-12-01

Seasonal changes in testicular activity, plasma luteinizing hormone (LH), estradiol (E2), testosterone (T), and 5 alpha-dihydrotestosterone (5 alpha-DHT) were related to pair bond formation, nest building, nest defense, and parental behavior in free-living Indian rose-ringed parakeets (Psittacula krameri) in northwest India. Spermatozoa production occurred between January and March when daylengths were short (10-12 hr) and ambient temperature was seasonally low (8-20 degrees C). At other times of the year the testes were regressed. Plasma LH levels increased during the prebreeding period (September-December) when the birds were forming pairs and selecting or defending nest sites. Plasma LH levels increased further between January and March and decreased to seasonal low values during the post breeding period between April and June when the birds were caring for young. Concentrations of plasma androgens and estrogens were similar during the prebreeding and postbreeding phases of the breeding cycle. During the breeding period, the ratios between plasma 5 alpha-DHT and testosterone and between plasma estradiol and testosterone increased. It is proposed that the absence of marked seasonal changes in plasma steroid levels is related to nest defense behavior which occurs during the prebreeding, breeding, and postbreeding phases of the breeding cycle. Winter breeding makes it possible for the parakeets to avoid competition with other birds for nesting sites, to avoid fledging young during the monsoon period, and to take advantage of the winter pea crop which provides the female with extra nutrients for egg production.

Cryptic forcible insemination: male snakes exploit female physiology, anatomy, and behavior to obtain coercive matings.

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Shine, Richard; Langkilde, Tracy; Mason, Robert T

2003-11-01

Whether males can inseminate uncooperative females is a central determinant of mating system evolution that profoundly affects the interpretation of phenomena such as multiple mating by females, mate choice, reproductive seasonality, and courtship tactics. Forcible insemination is usually inferred from direct physical battles between the sexes and has been dismissed on intuitive grounds for many kinds of animals. For example, snakes have elongate flexible bodies (making it difficult for a male to restrain a female physically), males are typically smaller than females, and copulation requires female cloacal gaping to enable intromission. Male garter snakes (Thamnophis sirtalis) do not display any overt aggression during courtship and simply lie over the female and exhibit rhythmic pulsating caudocephalic waves of muscular contraction; previous studies have interpreted this behavior as a mechanism for eliciting female receptivity. In contrast, we show that male garter snakes forcibly inseminate females. They do so by taking advantage of specific features of snake physiology, respiratory anatomy, and antipredator behavior. The snake lung extends along most of the body, with the large posterior section (the saccular lung) lacking any respiratory exchange surface. Rhythmic caudocephalic waves by courting male garter snakes push anoxic air from the saccular lung forward and across the respiratory surfaces such that females cannot obtain oxygen. Their stress response involves cloacal gaping, which functions in other contexts to repel predators by extruding feces and musk but in this situation permits male intromission. Thus, superficially benign courtship behaviors may involve cryptic coercion even in species for which intuition dismisses any possibility of forcible insemination.

Repeated embryo collection and interspecies transfer in alpacas and llamas during non-breeding season

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Pacheco J

2015-08-01

Full Text Available Sexual behavior evaluation was evaluated, collecting and interspecies embryo transfer inter species in llamas and alpacas during non-breeding season, 10 and 10 donor alpacas llamas, alpacas and 20 receiving 20 llamas, 5 alpacas and 5 llamas males were used. Sexual behavior by libido in males and acceptance of female to male in the presence of a dominant follicle was evaluated, the collection of embryos simple ovulation by non-surgical technique was performed and the fresh embryos are transferred directly into the horn left. It was observed that only 40% of alpaca accept the male and female in all cases had to use two males for mating, but all llama males mounted on the first attempt and accepted all females breeding. Embryos were collected at 25 and 60% of alpacas and llamas washes respectively, all were grade 1 embryos transferable; the embryo transfer fertility evaluated by ultrasound at 25 days was 100 and 41.6% respectively for donor alpaca and llama, however ultrasound evaluation at 60 days fertility was 50 and 25% respectively for donor alpaca and llama. We conclude that there is greater reproductive seasonality in alpaca regard to llamas, all were grade 1 embryos collected, fertility evaluated by ultrasound 25 days down to 60 days, demonstrating embryonic mortality, possibly due to the non-breeding season of both species.

Highly competitive reindeer males control female behavior during the rut.

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Guillaume Body

Full Text Available During the rut, female ungulates move among harems or territories, either to sample mates or to avoid harassment. Females may be herded by a male, may stay with a preferred male, or aggregate near a dominant male to avoid harassment from other males. In fission-fusion group dynamics, female movement is best described by the group's fission probability, instead of inter-harem movement. In this study, we tested whether male herding ability, female mate choice or harassment avoidance influence fission probability. We recorded group dynamics in a herd of reindeer Rangifer tarandus equipped with GPS collars with activity sensors. We found no evidence that the harassment level in the group affected fission probability, or that females sought high rank (i.e. highly competitive and hence successful males. However, the behavior of high ranked males decreased fission probability. Male herding activity was synchronous with the decrease of fission probability observed during the rut. We concluded that male herding behavior stabilized groups, thereby increasing average group size and consequently the opportunity for sexual selection.

Male microchimerism in the human female brain.

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William F N Chan

Full Text Available In humans, naturally acquired microchimerism has been observed in many tissues and organs. Fetal microchimerism, however, has not been investigated in the human brain. Microchimerism of fetal as well as maternal origin has recently been reported in the mouse brain. In this study, we quantified male DNA in the human female brain as a marker for microchimerism of fetal origin (i.e. acquisition of male DNA by a woman while bearing a male fetus. Targeting the Y-chromosome-specific DYS14 gene, we performed real-time quantitative PCR in autopsied brain from women without clinical or pathologic evidence of neurologic disease (n=26, or women who had Alzheimer's disease (n=33. We report that 63% of the females (37 of 59 tested harbored male microchimerism in the brain. Male microchimerism was present in multiple brain regions. Results also suggested lower prevalence (p=0.03 and concentration (p=0.06 of male microchimerism in the brains of women with Alzheimer's disease than the brains of women without neurologic disease. In conclusion, male microchimerism is frequent and widely distributed in the human female brain.

Asynchronous hatching provides females with a means for increasing male care but incurs a cost by reducing offspring fitness.

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Ford, L E; Smiseth, P T

2016-02-01

In species with biparental care, sexual conflict occurs because the benefit of care depends on the total amount of care provided by the two parents while the cost of care depends on each parent's own contribution. Asynchronous hatching may play a role in mediating the resolution of this conflict over parental care. The sexual conflict hypothesis for the evolution of asynchronous hatching suggests that females adjust hatching patterns in order to increase male parental effort relative to female effort. We tested this hypothesis in the burying beetle Nicrophorus vespilloides by setting up experimental broods with three different hatching patterns: synchronous, asynchronous and highly asynchronous broods. As predicted, we found that males provided care for longer in asynchronous broods whereas the opposite was true of females. However, we did not find any benefit to females of reducing their duration of care in terms of increased lifespan or reduced mass loss during breeding. We found substantial negative effects of hatching asynchrony on offspring fitness as larval mass was lower and fewer larvae survived to dispersal in highly asynchronous broods compared to synchronous or asynchronous broods. Our results suggest that, even though females can increase male parental effort by hatching their broods more asynchronously, females pay a substantial cost from doing so in terms of reducing offspring growth and survival. Thus, females should be under selection to produce a hatching pattern that provides the best possible trade-off between the benefits of increased male parental effort and the costs due to reduced offspring fitness. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

[Hindlimb antigravity muscles' reaction in male and female rats to the deficit of functional loading].

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Il'ina-Kakueva, E I

2002-01-01

Histological and histomorphometric comparison of the antigravity muscles of rats of both sexes was performed following 30-d unloading of their hind limbs by head-down suspension. It was shown that growth rate of control males was higher as compared to control females. This is attributed to the synergic effects of somatotropin and testosterone on metabolism and growth of males and only somatotropin in females. Load deprivation of the hind limbs inhibited body mass gain in all animals; however, this inhibition was twice as great in males. Increase of the soleus and gastrocnemius in the control males in this experiment was slightly ahead of the muscle mass gain in the females. The histomorphometric investigation of the cross-section area of myofibers did not reveal differences between males and females either in the control or suspension. No difference was found in percent of various types of fibers in the control males and females. In the soleus of the suspended rats, a part of slow fibers had transformed into fast ones without any sex-related particularities. The conclusion was made that despite the significant difference in the hormonal profile, the reaction of males and females to insufficient weight loading of the antigravity muscles was alike.

Males of Hylamorpha elegans burmeister (Coleoptera: Scarabaeidae) are attracted to odors released from conspecific females.

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Quiroz, Andrés; Palma, Ruben; Etcheverría, Paulina; Navarro, Vicente; Rebolledo, Ramón

2007-04-01

The behavioral responses of Hylamorpha elegans L. (Coleoptera: Scarabaeidae, Rutelinae) to the semiochemicals released from conspecific individual adults were studied, with particular attention paid to female attraction of males. Odors released from virgin females significantly attracted male conspecifics in both the field and laboratory olfactometer and wind tunnel bioassays. However, females did not attract other females, and males attracted no one. The response of male H. elegans to (1) compounds (1,4-hydroquinone and 1,4-benzoquinone) released only by unmated females; (2) the essential oil of the secondary host (Nothofagus obliqua); and (3) the blend of 1,4-hydroquinone and 1,4-benzoquinone with N. obliqua essential oil was studied. The blend of 1,4-benzoquinone mixed with essential oil at the trial concentration was attractive with males. The same response was found with 1,4-hydroquinone alone. The essential oil did not have the expected attractant effect on conspecific males. These results suggest that, when combined with essential oil, 1,4-benzoquinone may function in the sexual behavior of males and females. These findings are discussed in terms of the ecological role of this putative sexual pheromone and its potential use in a strategy of control of this pest.

Females of the communally breeding rodent, Octodon degus, transfer antibodies to their offspring during pregnancy and lactation.

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Becker, María Inés; De Ioannes, Alfredo E; León, Cecilia; Ebensperger, Luis A

2007-06-01

Females in numerous rodent species engage in communal nesting and breeding, meaning that they share a nest to rear their young together. One potential benefit to communally nesting mothers is that infants improve their immunocompetence. Thus, suckling from two or more females might provide newborns with a more diverse array of antibodies and defensive cells. As a first step toward testing the immunocompetence hypothesis, we assessed whether female degus (Octodon degus), a communally nesting and breeding caviomorph rodent, transfer immunoglobulins to their young through the yolk sac or placenta while in the uterus and, during lactation, through milk. With this aim, adult degu females were immunized with four antigens, including two mollusk hemocyanins from Concholepas and Megathura (CCH and KLH, respectively), porcine thyroglobulin and tetanus toxoid. Specific antibodies against the experimental antigens were used to track the origin of antibodies in the young. To establish the presence of specific antibodies of IgG and IgA isotypes in sera and milk of animals, an indirect enzyme-linked immunosorbent assay (ELISA) was developed. Degu females produced specific antibodies against antigens not found in their natural environment, and mothers were able to transfer the induced antibodies to their litters during pregnancy (IgG) and during lactation (IgA). However, we recorded only limited evidence of degu offspring acquiring antibodies from lactating mothers other than their own, giving little support to the increased immunocompetence hypothesis.

Alternative Mating Tactics in Male Chameleons (Chamaeleo chamaeleon) Are Evident in Both Long-Term Body Color and Short-Term Courtship Pattern

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Keren-Rotem, Tammy; Levy, Noga; Wolf, Lior; Bouskila, Amos; Geffen, Eli

2016-01-01

Alternative mating tactics in males of various taxa are associated with body color, body size, and social status. Chameleons are known for their ability to change body color following immediate environmental or social stimuli. In this study, we examined whether the differential appearance of male common chameleon during the breeding season is indeed an expression of alternative mating tactics. We documented body color of males and used computer vision techniques to classify images of individuals into discrete color patterns associated with seasons, individual characteristics, and social contexts. Our findings revealed no differences in body color and color patterns among males during the non-breeding season. However, during the breeding season males appeared in several color displays, which reflected body size, social status, and behavioral patterns. Furthermore, smaller and younger males resembled the appearance of small females. Consequently, we suggest that long-term color change in males during the breeding season reflects male alternative mating tactics. Upon encounter with a receptive female, males rapidly alter their appearance to that of a specific brief courtship display, which reflects their social status. The females, however, copulated indiscriminately in respect to male color patterns. Thus, we suggest that the differential color patterns displayed by males during the breeding season are largely aimed at inter-male signaling. PMID:27409771

Alternative Mating Tactics in Male Chameleons (Chamaeleo chamaeleon Are Evident in Both Long-Term Body Color and Short-Term Courtship Pattern.

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Tammy Keren-Rotem

Full Text Available Alternative mating tactics in males of various taxa are associated with body color, body size, and social status. Chameleons are known for their ability to change body color following immediate environmental or social stimuli. In this study, we examined whether the differential appearance of male common chameleon during the breeding season is indeed an expression of alternative mating tactics. We documented body color of males and used computer vision techniques to classify images of individuals into discrete color patterns associated with seasons, individual characteristics, and social contexts. Our findings revealed no differences in body color and color patterns among males during the non-breeding season. However, during the breeding season males appeared in several color displays, which reflected body size, social status, and behavioral patterns. Furthermore, smaller and younger males resembled the appearance of small females. Consequently, we suggest that long-term color change in males during the breeding season reflects male alternative mating tactics. Upon encounter with a receptive female, males rapidly alter their appearance to that of a specific brief courtship display, which reflects their social status. The females, however, copulated indiscriminately in respect to male color patterns. Thus, we suggest that the differential color patterns displayed by males during the breeding season are largely aimed at inter-male signaling.

Nest ornamentation by female spotless starlings in response to a male display: an experimental study.

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Polo, Vicente; Veiga, José P

2006-07-01

1. The use of behavioural traits by females in signalling condition has been practically ignored in evolutionary theory. However, females may also exhibit ornaments and behavioural displays, although less elaborated than those of males. 2. In this study we suggest that the carrying of feathers by spotless starlings Sturnus unicolor Temminck females to decorate the nest represents an elaborated and costly behaviour that is displayed in response to a courtship male behaviour: the carrying of nest green plants. 3. By experimentally increasing the amount of green plants in the nests, to give the appearance that highly attractive males defended them, we induced females to increase their feather carrying rates. 4. The amount of feathers carried to the nest was correlated to female reproductive experience and laying date, two variables correlated with female body condition. These results suggests that this behaviour may work as an honest indicator of female quality. 5. We conclude that male carrying plants and female carrying feathers can be viewed as two sex-specific functionally related signalling behaviours involved in mutual courtship or status signalling.

Differential effects of male nutrient balance on pre- and post-copulatory traits, and consequences for female reproduction in Drosophila melanogaster

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Morimoto, Juliano; Wigby, Stuart

2016-01-01

Male fitness depends on the expression of costly traits involved in obtaining mates (pre-copulatory) and fertilization (post-copulatory). However, very little is known about the nutrient requirements for these traits and whether males compromise their diet to maximize one trait at the expense of another. Here we used Nutritional Geometry to investigate macronutrient requirements for pre- and post-copulatory traits in Drosophila, when males were the first or second to mate with females. We found no significant effects of male diet on sperm competitiveness. However, although males self-regulate their macronutrient intake at a protein-to-carbohydrate ratio (“P:C ratio”) of 1:1.5, this ratio does not coincide with their optima for several key reproductive traits: both the short-term (~24 hr) rate of offspring production after a female’s first mating, as well as the total offspring number sired when males were second to mate were maximized at a P:C ratio of 1:9, whereas male attractiveness (latency to mate), were maximised at a P:C ratio of 1:1. These results suggest a compromised optimum diet, and no single diet that simultaneously maximizes all male reproductive traits. The protein intake of first males also negatively affected female offspring production following remating, suggesting a long-term intersexual effect of male nutrition. PMID:27270223

Survival during the Breeding Season: Nest Stage, Parental Sex, and Season Advancement Affect Reed Warbler Survival.

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Kaja Wierucka

Full Text Available Avian annual survival has received much attention, yet little is known about seasonal patterns in survival, especially of migratory passerines. In order to evaluate survival rates and timing of mortality within the breeding season of adult reed warblers (Acrocephalus scirpaceus, mark-recapture data were collected in southwest Poland, between 2006 and 2012. A total of 612 individuals (304 females and 308 males were monitored throughout the entire breeding season, and their capture-recapture histories were used to model survival rates. Males showed higher survival during the breeding season (0.985, 95% CI: 0.941-0.996 than females (0.869, 95% CI: 0.727-0.937. Survival rates of females declined with the progression of the breeding season (from May to August, while males showed constant survival during this period. We also found a clear pattern within the female (but not male nesting cycle: survival was significantly lower during the laying, incubation, and nestling periods (0.934, 95% CI: 0.898-0.958, when birds spent much time on the nest, compared to the nest building and fledgling periods (1.000, 95% CI: 1.00-1.000, when we did not record any female mortality. These data (coupled with some direct evidence, like bird corpses or blood remains found next to/on the nest may suggest that the main cause of adult mortality was on-nest predation. The calculated survival rates for both sexes during the breeding season were high compared to annual rates reported for this species, suggesting that a majority of mortality occurs at other times of the year, during migration or wintering. These results have implications for understanding survival variation within the reproductive period as well as general trends of avian mortality.

Habitat and sex differences in physiological condition of breeding Southwestern Willow Flycatchers (Empidonax traillii extimus)

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Owen, J.C.; Sogge, M.K.; Kern, M.D.

2005-01-01

The Southwestern Willow Flycatcher (Empidonax traillii extimus; here- after “flycatcher”) is a federally listed endangered species that breeds in densely vegetated riparian habitats dominated by native and exotic plants, including introduced monotypic saltcedar (Tamarix ramosissima). Some workers have theorized that saltcedar is unsuitable habitat for the flycatcher, primarily because it generally supports a smaller and less diverse invertebrate community (the flycatcher's food base) than native habitats (e.g. Salix spp.). However, differences in insect communities between native and saltcedar habitats are not proof that saltcedar habitats are inferior. The only way to evaluate whether the habitats differ in dietary or energetic quality is to document actual food limitation or its manifestations. Measurements of an individual's body condition and metabolic state can serve as indicators of environmental stressors, such as food limitation and environmental extremes. We captured 130 flycatchers breeding in native and saltcedar habitats in Arizona and New Mexico and measured 12 variables of physiological condition. These variables included body mass, fat level, body condition index, hematocrit, plasma triglycerides, plasma free fatty acids and glycerol, plasma glucose and beta-hydroxybutyrate, plasma uric acid, total leukocyte count, and heterophil-to-lymphocyte ratio. We found substantial sex-based differences in the condition of male and female flycatchers. Ten of the 12 measures of physiological condition differed significantly between the sexes. In all cases where male and female condition differed (except mass), the differences suggest that males were in poorer condition than females. We found few habitat-based differences in flycatcher condition. Only 3 of the 12 physiological condition indices differed significantly between habitats. Our data show that, at least in some parts of the flycatcher's range, there is no evidence that flycatchers breeding in

Hot or not: the effects of exogenous testosterone on female attractiveness to male conspecifics in the budgerigar.

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Stefanie E P Lahaye

Full Text Available An increasing number of studies indicate that not only females but also males can be selective when choosing a mate. In species exhibiting male or mutual mate choice, females may benefit from being attractive. While male attractiveness is often positively influenced by higher plasma levels of the androgenic hormone testosterone, it has been shown that testosterone can masculinise female behavior and morphology in several bird species, potentially rendering them less attractive. In this study, we investigated whether female budgerigars, Melopsittacusundulatus, suffer from increased plasma testosterone levels through a negative effect on their attractiveness to males. We experimentally increased plasma testosterone levels in testosterone-treated females (T-females compared to controls (C-females and allowed males to choose between a T- and a C-female in a two-way choice situation. Although testosterone treatment significantly affected female behavioral and morphological characteristics, males did not show a significant difference in preference between T- and C-females. These results suggest that experimentally increasing testosterone levels in females does not appear to influence male preference during initial mate choice. Our findings indicate that selection for higher levels of testosterone in male budgerigars is probably not constrained by a correlated response to selection causing negative effects on female attractiveness during initial mate choice. Evaluating whether or not a potential constraint may arise from negative testosterone-induced effects on other fitness related traits in females requires further work.

What makes a nest-building male successful? Male behavior and female care in penduline tits

NARCIS (Netherlands)

Szentirmai, [No Value; Komdeur, J; Szekely, T; Szentirmai, István

Why do females increase parental effort when caring for the offspring of attractive males? First, attractive males may be poor fathers so that their females are compelled to increase their own contribution in order to fledge some young (the partner-compensation hypothesis). Second, females mated to

Investment in testes, sperm-duct glands and lipid reserves differs between male morphs but not between early and late breeding season in Pomatoschistus minutus.

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Kvarnemo, C; Svensson, O; Manson, W

2010-05-01

This study of the sand goby Pomatoschistus minutus, a nest-holding fish with paternal care, focused on gonadal investment among males of different sizes collected early and late in the breeding season. All males caught at the nest had breeding colour, whereas trawl-caught fish consisted of males both with and without colour. The absence or presence of breeding colour was a good predictor of testes investment. Compared to males with breeding colour, males without colour were smaller in body size but had extraordinarily large testes. In absolute terms, testes mass of males without breeding colour was on average 3.4 times greater than those of males with breeding colour. Since small colourless males are known to reproduce as sneaker males, this heavy investment in testes probably reflects that they are forced to spawn under sperm competition. Contrary to testes size, sperm-duct glands were largest among males with breeding colour. These glands produce mucins used for making sperm-containing mucous trails that males place in the nest before and during spawning. Since both sneakers and nest-holders potentially could benefit from having large glands, this result is intriguing. Yet, high mucus production may be more important for nest-holders, because it also protects developing embryos from infections. There was no significant effect of season on body size, testes or sperm-duct glands size, but colourless males tended to be less common late in the season. Possibly this may indicate that individual small colourless males develop into their more colourful counterparts within the breeding season.

Female behaviour and the interaction of male and female genital traits mediate sperm transfer during mating.

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Friesen, C R; Uhrig, E J; Mason, R T; Brennan, P L R

2016-05-01

Natural selection and post-copulatory sexual selection, including sexual conflict, contribute to genital diversification. Fundamental first steps in understanding how these processes shape the evolution of specific genital traits are to determine their function experimentally and to understand the interactions between female and male genitalia during copulation. Our experimental manipulations of male and female genitalia in red-sided garter snakes (Thamnophis sirtalis parietalis) reveal that copulation duration and copulatory plug deposition, as well as total and oviductal/vaginal sperm counts, are influenced by the interaction between male and female genital traits and female behaviour during copulation. By mating females with anesthetized cloacae to males with spine-ablated hemipenes using a fully factorial design, we identified significant female-male copulatory trait interactions and found that females prevent sperm from entering their oviducts by contracting their vaginal pouch. Furthermore, these muscular contractions limit copulatory plug size, whereas the basal spine of the male hemipene aids in sperm and plug transfer. Our results are consistent with a role of sexual conflict in mating interactions and highlight the evolutionary importance of female resistance to reproductive outcomes. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Reduced costs of reproduction in females mediate a shift from a male-biased to a female-biased lifespan in humans

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Bolund, Elisabeth; Lummaa, Virpi; Smith, Ken R.; Hanson, Heidi A.; Maklakov, Alexei A.

2016-01-01

The causes underlying sex differences in lifespan are strongly debated. While females commonly outlive males in humans, this is generally less pronounced in societies before the demographic transition to low mortality and fertility rates. Life-history theory suggests that reduced reproduction should benefit female lifespan when females pay higher costs of reproduction than males. Using unique longitudinal demographic records on 140,600 reproducing individuals from the Utah Population Database, we demonstrate a shift from male-biased to female-biased adult lifespans in individuals born before versus during the demographic transition. Only women paid a cost of reproduction in terms of shortened post-reproductive lifespan at high parities. Therefore, as fertility decreased over time, female lifespan increased, while male lifespan remained largely stable, supporting the theory that differential costs of reproduction in the two sexes result in the shifting patterns of sex differences in lifespan across human populations. Further, our results have important implications for demographic forecasts in human populations and advance our understanding of lifespan evolution. PMID:27087670

The cost of reproduction: differential resource specialization in female and male California sea otters.

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Smith, Emma A Elliott; Newsome, Seth D; Estes, James A; Tinker, M Tim

2015-05-01

Intraspecific variation in behavior and diet can have important consequences for population and ecosystem dynamics. Here, we examine how differences in reproductive investment and spatial ecology influence individual diet specialization in male and female southern sea otters (Enhydra lutris nereis). We hypothesize that greater reproductive constraints and smaller home ranges of females lead to more pronounced intraspecific competition and increased specialization. We integrate stable carbon (δ(13)C) and nitrogen (δ(15)N) isotope analysis of sea otter vibrissae with long-term observational studies of five subpopulations in California. We define individual diet specialization as low ratios of within-individual variation (WIC) to total population niche width (TNW). We compare isotopic and observational based metrics of WIC/TNW for males and females to data on population densities, and movement patterns using both general linear and linear mixed-effects models. Consistent with our hypothesis, increasing population density is associated with increased individual diet specialization by females but not by males. Additionally, we find the amount of coastline in a sea otter's home range positively related with individual dietary variability, with increased range span resulting in weaker specialization for both males and females. We attribute our results to sex-based differences in movement, with females needing to specialize in their small ranges to maximize energy gain, and posit that the paradigm of individual prey specialization in sea otters with increased intraspecific competition may be a pattern driven largely by females. Our work highlights a potentially broader role of sex in the mechanistic pressures promoting and maintaining diet specialization.

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

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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.

Effect of Amphetamine on Adult Male and Female Rats Prenatally Exposed to Methamphetamine

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Romana Šlamberová

2014-01-01

Full Text Available The aim of the present study was to examine the cross-sensitization induced by prenatal methamphetamine (MA exposure to adult amphetamine (AMP treatment in male and female rats. Rat mothers received a daily injection of MA (5 mg/kg or saline throughout the gestation period. Adult male and female offspring (prenatally MA- or saline-exposed were administered with AMP (5 mg/kg or saline (1 ml/kg in adulthood. Behaviour in unknown environment was examined in open field test (Laboras, active drug-seeking behaviour in conditioned place preference test (CPP, spatial memory in the Morris water maze (MWM, and levels of corticosterone (CORT were analyzed by enzyme immunoassay (EIA. Our data demonstrate that in Laboras test, AMP treatment in adulthood increased general locomotion (time and distance travelled regardless of the prenatal exposure and sex, while AMP increased exploratory activity (rearing only in prenatally MA-exposed animals. AMP induced sensitization only in male rats, but not in females when tested drug-seeking behaviour in the CPP test. In the spatial memory MWM test, AMP worsened the performance only in females, but not in males. On the other hand, males swam faster after chronic AMP treatment regardless of the prenatal drug exposure. EIA analysis of CORT levels demonstrated higher level in females in all measurement settings. In males, prenatal MA exposure and chronic adult AMP treatment decreased CORT levels. Thus, our data demonstrated that adult AMP treatment affects behaviour of adult rats, their spatial memory and stress response in sex-specific manner. The effect is also influenced by prenatal drug exposure.

The origin of parental care in relation to male and female life history.

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Klug, Hope; Bonsall, Michael B; Alonzo, Suzanne H

2013-04-01

The evolution of maternal, paternal, and bi-parental care has been the focus of a great deal of research. Males and females vary in basic life-history characteristics (e.g., stage-specific mortality, maturation) in ways that are unrelated to parental investment. Surprisingly, few studies have examined the effect of this variation in male and female life history on the evolution of care. Here, we use a theoretical approach to determine the sex-specific life-history characteristics that give rise to the origin of paternal, maternal, or bi-parental care from an ancestral state of no care. Females initially invest more into each egg than males. Despite this inherent difference between the sexes, paternal, maternal, and bi-parental care are equally likely when males and females are otherwise similar. Thus, sex differences in initial zygotic investment do not explain the origin of one pattern of care over another. However, sex differences in adult mortality, egg maturation rate, and juvenile survival affect the pattern of care that will be most likely to evolve. Maternal care is more likely if female adult mortality is high, whereas paternal care is more likely if male adult mortality is high. These findings suggest that basic life-history differences between the sexes can alone explain the origin of maternal, paternal, and bi-parental care. As a result, the influence of life-history characteristics should be considered as a baseline scenario in studies examining the origin of care.

Breeding system and parental effect on fruit characters of Idesia polycarpa (Flacourtiaceae), a promising plant for biodiesel, in northwest China

International Nuclear Information System (INIS)

Wang, S.H.; Li, Z.Q.; Xie, Q.

2017-01-01

Idesia polycarpa Maxim. is a promising plant for biodiesel in China. We have reported the flowering phenology, breeding system and parental effect on fruit characters of this species distributed in Qinling-Bashan Mountain (Shaanxi Province) nature reserve. As a dioecious plant, the male and female flowered almost synchronously. The anthesis was from around 10th of May and proceeded until the end of May or the beginning of June at population level. To determine the breeding system of I. polycarpa, three pollination treatments were carried out on every three female plants: natural pollination (NP), apomixy (AP) and cross pollination (CP). Reproductive success of apoximy treatment indicated that, as a dioecious plant, I. polycarpa could also reproduce by apomixis. However, the mean fruit set under apomixy treatment was markerly lower (3.6–13.33%) than that of two pollination treatments (>65.69%). Fruit quality (fruit length, fruit width, 100 fruit weight, seed production and seed germination) of the cross pollination treatment was greater than the other two treatments, suggested that pollen competition in cross pollination treatment was the most intense in three treatments. To study parental effect on fruit characters, cross pollination was carried out with three female plants and three male plants. The result showed that maternal parents (P<0.001) and parental interaction significantly affected all the fruit characters (including 100 fruit weight, pulp/fruit ratio, oil content and seed germination) while paternal parents showed significant effects on 100 fruit weight, pulp/fruit ratio and seed germination. Fruit set was only significantly affected by maternal parents (P=0.001). Our findings will facilitate future breeding programs of I. polycarpa in parental selection. (author)

Potential contribution of progesterone receptors to the development of sexual behavior in male and female mice.

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Desroziers, Elodie; Brock, Olivier; Bakker, Julie

2017-04-01

We previously showed that estradiol can have both defeminizing and feminizing effects on the developing mouse brain. Pre- and early postnatal estradiol defeminized the ability to show lordosis in adulthood, whereas prepubertal estradiol feminized this ability. Furthermore, we found that estradiol upregulates progesterone receptors (PR) during development, inducing both a male-and female-typical pattern of PR expression in the mouse hypothalamus. In the present study, we took advantage of a newly developed PR antagonist (ZK 137316) to determine whether PR contributes to either male- or female-typical sexual differentiation. Thus groups of male and female C57Bl/6j mice were treated with ZK 137316 or OIL as control: males were treated neonatally (P0-P10), during the critical period for male sexual differentiation, and females were treated prepubertally (P15-P25), during the critical period for female sexual differentiation. In adulthood, mice were tested for sexual behavior. In males, some minor effects of neonatal ZK treatment on sexual behavior were observed: latencies to the first mount, intromission and ejaculation were decreased in neonatally ZK treated males; however, this effect disappeared by the second mating test. By contrast, female mice treated with ZK during the prepubertal period showed significantly less lordosis than OIL-treated females. Mate preferences were not affected in either males or females treated with ZK during development. Taken together, these results suggest a role for PR and thus perhaps progesterone in the development of lordosis behavior in female mice. By contrast, no obvious role for PR can be discerned in the development of male sexual behavior. Copyright © 2016 Elsevier Inc. All rights reserved.

Personal and practice profile of male and female ophthalmologists in India

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Kumar Saurabh

2015-01-01

Full Text Available Background: The aim of this study was to study the practice pattern, personal profile, and work-family balance of male and female ophthalmologists in India. Materials and Methods: This study was conducted through 41 point questionnaire sent to the members of All India Ophthalmological Society dealing with practice profile and personal circumstances of ophthalmologists. Results: Six hundred and twenty-two (8% responses were obtained out of 7723 invitations sent. A total of 452 were male and 170 were female ophthalmologists. Age group of 30-39 years was most common age of respondents (male 155; 35.3%; female 81; 47.6%. Larger number of male ophthalmologists (157; 34.7% worked for more than 9 h a day than female ophthalmologists (41; 24.1% (P = 0.01. Larger number of male ophthalmologists (229; 50.7% earned more than Rs. 1 lakh/month than female ophthalmologists (55; 32.4% (P = 0.00001 More female ophthalmologists (21; 12.4% than males (26; 5.8% said that they faced cultural, ethnic or gender bias at work place (P = 0.002. Forty-four (25.9% female and 54 (12% male ophthalmologists said that they often curtailed their work for family needs (P = 0.0001. Two hundred and fifty-two (55.8% male ophthalmologists and 78 (45.9% female ophthalmologists considered their profession rewarding (P = 0.02. Conclusion: Ophthalmology as a profession was considered rewarding by both male and female ophthalmologists. However, female ophthalmologists were curtailing their work for family needs and earning less than male ophthalmologists. Female ophthalmologists were also subject to gender bias at workplace. These issues need to be tackled to improve the work satisfaction of ophthalmology workforce.

Female distance education students overtaking males in science ...

African Journals Online (AJOL)

This study was initiated to compare the performance of male and female distance education students of the University of Education, Winneba in Integrated Science. This was done by randomly selecting the cumulated grades of male and female students of 2002, 2003 and 2004-year groups in Integrated Science for analysis ...

Analysis on burnup step effect for evaluating reactor criticality and fuel breeding ratio

International Nuclear Information System (INIS)

Saputra, Geby; Purnama, Aditya Rizki; Permana, Sidik; Suzuki, Mitsutoshi

2014-01-01

Criticality condition of the reactors is one of the important factors for evaluating reactor operation and nuclear fuel breeding ratio is another factor to show nuclear fuel sustainability. This study analyzes the effect of burnup steps and cycle operation step for evaluating the criticality condition of the reactor as well as the performance of nuclear fuel breeding or breeding ratio (BR). Burnup step is performed based on a day step analysis which is varied from 10 days up to 800 days and for cycle operation from 1 cycle up to 8 cycles reactor operations. In addition, calculation efficiency based on the variation of computer processors to run the analysis in term of time (time efficiency in the calculation) have been also investigated. Optimization method for reactor design analysis which is used a large fast breeder reactor type as a reference case was performed by adopting an established reactor design code of JOINT-FR. The results show a criticality condition becomes higher for smaller burnup step (day) and for breeding ratio becomes less for smaller burnup step (day). Some nuclides contribute to make better criticality when smaller burnup step due to individul nuclide half-live. Calculation time for different burnup step shows a correlation with the time consuming requirement for more details step calculation, although the consuming time is not directly equivalent with the how many time the burnup time step is divided

Disparities in Chronic Kidney Disease Prevalence among Males and Females in 195 Countries: Analysis of the Global Burden of Disease 2016 Study.

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Bikbov, Boris; Perico, Norberto; Remuzzi, Giuseppe

2018-05-23

Chronic kidney disease (CKD) imposes a substantial burden on health care systems. There are some especially vulnerable groups with a high CKD burden, one of which is women. We performed an analysis of gender disparities in the prevalence of all CKD stages and renal replacement therapy (defined as impaired kidney function [IKF]) in 195 countries. We used estimates produced by the Global Burden of Disease (GBD) Study 2016 revision using a Bayesian-regression analytic tool, DisMoD-MR 2.1. Data on gross domestic product based on purchasing power parity per capita (GDP PPP) was obtained via the World Bank International Comparison Program database. To estimate gender disparities, we calculated the male:female all-age prevalence rate ratio for each IKF condition. In 2016, the global number of individuals with IKF reached 752.7 million, including 417.0 million females and 335.7 million males. The most prevalent form of IKF in both groups was albuminuria with preserved glomerular filtration rate. Geospatial analysis shows a very heterogeneous distribution of the male:female ratio for all IKF conditions, with the most prominent contrast found in kidney transplant patients. The median male:female ratio varies substantially according to GDP PPP quintiles; however, countries with different economic states could have similar male:female ratios. A strong correlation of GDP PPP with dialysis-to-transplant ratio was found. The GBD study highlights the prominent gender disparities in CKD prevalence among 195 countries. The nature of these disparities, however, is complex and must be interpreted cautiously taking into account all possible circumstances. © 2018 S. Karger AG, Basel.

The relationship between female brooding and male nestling provisioning: does climate underlie geographic variation in sex roles?

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Yoon, Jongmin; Sofaer, Helen R.; Sillett, T. Scott; Morrison, Scott A.; Ghalambor, Cameron K.

2017-01-01

Comparative studies of populations occupying different environments can provide insights into the ecological conditions affecting differences in parental strategies, including the relative contributions of males and females. Male and female parental strategies reflect the interplay between ecological conditions, the contributions of the social mate, and the needs of offspring. Climate is expected to underlie geographic variation in incubation and brooding behavior, and can thereby affect both the absolute and relative contributions of each sex to other aspects of parental care such as offspring provisioning. However, geographic variation in brooding behavior has received much less attention than variation in incubation attentiveness or provisioning rates. We compared parental behavior during the nestling period in populations of orange-crowned warblers Oreothlypis celata near the northern (64°N) and southern (33°N) boundaries of the breeding range. In Alaska, we found that males were responsible for the majority of food delivery whereas the sexes contributed equally to provisioning in California. Higher male provisioning in Alaska appeared to facilitate a higher proportion of time females spent brooding the nestlings. Surprisingly, differences in brooding between populations could not be explained by variation in ambient temperature, which was similar between populations during the nestling period. While these results represent a single population contrast, they suggest additional hypotheses for the ecological correlates and evolutionary drivers of geographic variation in brooding behavior, and the factors that shape the contributions of each sex.

Preferred Leadership Behaviours of Male and Female Badminton Players

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Rajkumar S HARMA

2015-06-01

Full Text Available Pr eferences for specific coaching behaviours of male and female Badminton players were measured by the modified and revised Leadership Scale for Sport. Eighty two (Males=61, Females=21 badminton players were selected from amongst the players representing th eir respective university teams in East - zone Inter - university Badminton (Men/Women tournaments held at Bilaspur (CG. The present investigation noted the statistically significant differences among East - zone Inter - university level male as well as female B adminton player’s preferences for specific coaching behaviour. Differences were not observed between male and female badminton players in all the dimensions together of specific coaching behaviours of preferred leadership. It is recommended that coaches a lign their coaching style to meet the needs of their teams.

An index to characterize female career promotion in academic medicine.

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Brüggmann, Dörthe; Groneberg, David A

2017-01-01

Imbalances in female career promotion are a key factor of gender disparities at the workplace. They may lead to stress and stress-related diseases including burnout, depression or cardiovascular diseases. Since this problem cannot be generalized and varies between different fields, new approaches are needed to assess and describe the magnitude of the problem in single fields of work. To construct a new index, operating figures of female and male medical students were collected for Germany in a period over 15 years and their progression throughout their studies towards specialization and academic chair positions. By the use of different female to male ratios (f:m), we constructed an index that describes the extend by which women can ascent in their academic career by using the field of academic medicine as an example. A medical student f:m ratio of 1.54 (52,366 female vs. 34,010 male) was found for Germany in 2013. In 1998, this f:m ratio was 0.999. In the same year (2013), the OB/GYN hospital specialists' f:m ratio was 1.566 (3347 female vs. 2137 male physicians) and 0.577 (516 female vs 894 male physicians) for ENT hospital specialists, respectively. The f:m ratios concerning chairs of OB/GYN and ENT were 0.105 and 0.1, respectively. Then an index was generated that incorporated these operating figures with the student f:m ratio as denominator and the chair f:m ratio as numerator while the hospital specialist f:m ratio served as a corrector in the numerator in order to adjust to the attraction of a given field to female physicians. As a result, the index was 0.044 for OB/GYN and 0.113 for ENT instead of ideally ~1 in a completely gender harmonized situation. In summary, a new index to describe female career advancement was established for academic medicine. By the use of this index, different academic and medical fields can now be compared to each other and future benchmarks could be proposed. Also, country differences may be examined using the proposed index and

Sex-role reversal of a monogamous pipefish without higher potential reproductive rate in females.

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Sogabe, Atsushi; Yanagisawa, Yasunobu

2007-12-07

In monogamous animals, males are usually the predominant competitors for mates. However, a strictly monogamous pipefish Corythoichthys haematopterus exceptionally exhibits a reversed sex role. To understand why its sex role is reversed, we measured the adult sex ratio and the potential reproductive rate (PRR), two principal factors influencing the operational sex ratio (OSR), in a natural population of southern Japan. The adult sex ratio was biased towards females throughout the breeding season, but the PRR, which increased with water temperature, did not show sexual difference. We found that an alternative index of the OSR (Sf/Sm: sex ratio of 'time in') calculated from the monthly data was consistently biased towards females. The female-biased OSR associated with sex-role reversal has been reported in some polyandrous or promiscuous pipefish, but factors biasing the OSR differed between these pipefish and C. haematopterus. We concluded that the similar PRR between the sexes in C. haematopterus does not confer reproductive benefit of polygamous mating on either sex, resulting in strict monogamous mating, and its female-biased adult sex ratio promotes female-female competition for a mate, resulting in sex-role reversal.

Suboptimal Nutritional Characteristics in Male and Female Soldiers Compared to Sports Nutrition Guidelines.

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Beals, Kim; Darnell, Matthew E; Lovalekar, Mita; Baker, Rachel A; Nagai, Takashi; San-Adams, Thida; Wirt, Michael D

2015-12-01

The purpose of this study was to evaluate the nutrient intake of male and female Soldiers in the 101 st Airborne Division (Air Assault) compared to sports nutrition standards for athletes, and to identify suboptimal eating characteristics that may impair physical performance and jeopardize military readiness. Male and female Soldiers from the 101 st Airborne Division (Air Assault) completed a 24-hour dietary recall and nutrition history questionnaire before anthropometric and body composition measurements were taken. Compared to sports nutrition guidelines, Soldiers of the 101 st under consume carbohydrates (males: 3.9 ± 2.0 vs. 5.0 g/kg, p < 0.001; females: 4.0 ± 2.1 vs. 5.0 g/kg, p = 0.001), male Soldiers eat too much fat (32.4% of kcal vs. <30% of kcal, p = 0.000) and saturated fat (males: 10.5 ± 3.9% of kcal vs. 10.0% of kcal, p = 0.044), and both males and females follow a meal pattern that may not optimize energy availability throughout the day. Eating too much fat and under fueling carbohydrate may negatively impact the adaptations to physical training and compromise overall health. Although Soldiers continue to participate in arduous training programs, future research should be aimed at determining the energy and macronutrient needs to fuel and recover from specific types of military training. Reprint & Copyright © 2015 Association of Military Surgeons of the U.S.

Breeding schemes in reindeer husbandry

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Lars Rönnegård

2003-04-01

Full Text Available The objective of the paper was to investigate annual genetic gain from selection (G, and the influence of selection on the inbreeding effective population size (Ne, for different possible breeding schemes within a reindeer herding district. The breeding schemes were analysed for different proportions of the population within a herding district included in the selection programme. Two different breeding schemes were analysed: an open nucleus scheme where males mix and mate between owner flocks, and a closed nucleus scheme where the males in non-selected owner flocks are culled to maximise G in the whole population. The theory of expected long-term genetic contributions was used and maternal effects were included in the analyses. Realistic parameter values were used for the population, modelled with 5000 reindeer in the population and a sex ratio of 14 adult females per male. The standard deviation of calf weights was 4.1 kg. Four different situations were explored and the results showed: 1. When the population was randomly culled, Ne equalled 2400. 2. When the whole population was selected on calf weights, Ne equalled 1700 and the total annual genetic gain (direct + maternal in calf weight was 0.42 kg. 3. For the open nucleus scheme, G increased monotonically from 0 to 0.42 kg as the proportion of the population included in the selection programme increased from 0 to 1.0, and Ne decreased correspondingly from 2400 to 1700. 4. In the closed nucleus scheme the lowest value of Ne was 1300. For a given proportion of the population included in the selection programme, the difference in G between a closed nucleus scheme and an open one was up to 0.13 kg. We conclude that for mass selection based on calf weights in herding districts with 2000 animals or more, there are no risks of inbreeding effects caused by selection.

Sharing mates and nest boxes is associated with female "friendship" in European starlings, Sturnus vulgaris.

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Henry, Laurence; Bourguet, Cécile; Coulon, Marion; Aubry, Christine; Hausberger, Martine

2013-02-01

Breeding decisions in birds involve both mate and nest choice, and there is increasing evidence that social influences may modulate individual choices. Female preferences may be affected by other females' preferences and mutual choice cannot always be excluded, which makes the whole pattern more complex than assumed by most sexual selection models. Social transmission may be facilitated by particular social bonds, therefore prebreeding social networks may influence later mate choices. The other case where females share mate or resources is polygyny, generally viewed to only benefit males. If mutual benefits may arise then mechanisms should evolve to reduce the reproductive cost for females such as to reduce the cost of aggression by sharing their mate with a preferred same-sex social partner. We tested the hypothesis that females' mating decisions may be influenced by the prebreeding social network and that social partner relations established prior to breeding may share decisions (mate/sites) in a facultatively polygynous species, the European starling. Two experiments were designed to test the relative importance of male or nest by following the whole dynamics of the breeding cycle from the prebreeding period until mate and nest selection. In both cases socially isolated females tended to be excluded from breeding, while prebreeding social partners tended to share mates and to nest in close proximity, mate copying leading in some case to polygyny. The final pattern resulted both from female "likes and dislikes" and male preferences for some females. Aggressive interactions between females were rare. Vocal sharing between females may have been a clue for males as to the degree of social integration of these females. PsycINFO Database Record (c) 2013 APA, all rights reserved

The evolution of female sex pheromones

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Ally R. HARARI, Hadass STEINITZ

2013-08-01

Full Text Available The role of female sex pheromones in natural selection, particularly as a means for species recognition to avoid the generation of hybrid offspring with low fitness, has been widely explored and is generally accepted by scholars. However, the significance of sex pheromones in shaping mate choice (sexual selection and in competition over breeding resources (social selection has been largely ignored. The effect of sexual selection on sex pheromones as a sexually dimorphic signaling trait has been discounted because the amount of pheromone released by females is typically minute, while the role of sex pheromones in competition over breeding resources (other than mates has not yet been considered. As a result of natural selection, variation in sex pheromones among females is expected to be low, and males are not expected to choose their mates among pheromone-releasing conspecific females. Sexual selection, on the other hand, should drive the increase in pheromone variance among females, and males are expected to choose females based on this variation. Moreover, social selection resulting from more general social interactions, for example competition among females for breeding sites and food, should also promote variance among female sex pheromones. Here, we review the current evidence for each of the three selection processes acting on sex pheromones of female moths as an advertising trait. We suggest that the three selection types are not mutually exclusive but rather act together to promote different fitness components in diverse ecological situations [Current Zoology 59 (4: 569–578, 2013].

Reproductive maturation and breeding of woodcock in North Carolina

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Stamps, R.T.; Doerr, P.D.; Keppie, Daniel M.; Owen, Ray B.

1977-01-01

Breeding woodcock (PhiJohela minor) were studied in North Carolina during the winters and springs of 1974-75 and 1975-76.. Measurements of testes and ovaries from 19 male and 30 female woodcock suggest that gonadal recrudescence in many woodcock occurs on the wintering grounds. In males, testicular recrudescence occurred as early as December and was accompanied by territory selection and courtship activity. Of 15 females collected in February, 5 had shelled eggs in the oviduct. Seven woodcock broods, located from 1 March to 30 April, were banded, aged, and released. From estimated clutch completion dates it appears that broods were successfully hatched from clutches completed as early as 21 January. Because of the early nesting of woodcock in North Carolina, hunters and land managers need to be aware of woodcock breeding habits and their need for protection during late winter.

Quantifying the life-history response to increased male exposure in female Drosophila melanogaster.

Science.gov (United States)

Edward, Dominic A; Fricke, Claudia; Gerrard, Dave T; Chapman, Tracey

2011-02-01

Precise estimates of costs and benefits, the fitness economics, of mating are of key importance in understanding how selection shapes the coevolution of male and female mating traits. However, fitness is difficult to define and quantify. Here, we used a novel application of an established analytical technique to calculate individual- and population-based estimates of fitness-including those sensitive to the timing of reproduction-to measure the effects on females of increased exposure to males. Drosophila melanogaster females were exposed to high and low frequencies of contact with males, and life-history traits for each individual female were recorded. We then compared different fitness estimates to determine which of them best described the changes in life histories. We predicted that rate-sensitive estimates would be more accurate, as mating influences the rate of offspring production in this species. The results supported this prediction. Increased exposure to males led to significantly decreased fitness within declining but not stable or increasing populations. There was a net benefit of increased male exposure in expanding populations, despite a significant decrease in lifespan. The study shows how a more accurate description of fitness, and new insights can be achieved by considering individual life-history strategies within the context of population growth. © 2010 The Author(s). Evolution© 2010 The Society for the Study of Evolution.

Variations in the Gender Ratio of Multiple Sclerosis Linked to Converging Smoking Trends in Men and Women

DEFF Research Database (Denmark)

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

2010-01-01

-dependent relationship exists between changing female-to male ratios of smoking and Multiple Sclerosis (MS) in worldwide birth cohorts from previously published studies. BACKGROUND: Smoking behavior in industrialized nations has changed dramatically over the second half of the 20th century, with diverging patterns...... in male and female smoking rates. During the same time period, an increase in the female to male ratio in MS incidence has been reported. We examined whether MS incidence in the two genders changed concomitantly with smoking, as would be expected if smoking truly increased MS risk. DESIGN/METHODS: We...... identified relevant studies reporting male and female age-specific incidence of MS throughout the world using within-country birth cohorts as units of observation. For each country and birth cohort, we then estimated the male to female ratio in MS incidence, and correlated these ratios with the corresponding...

Male and Female Secondary School EFL Teachers' Code ...

African Journals Online (AJOL)

This study explored male and female secondary school EFL teachers' attitudes, reasons and beliefs about the functions of code-switching to L1 (Amharic) in their classes. The participants of the study were all the available (38 male and 19 female) English language teachers in seven secondary schools in Bahir Dar City and ...

Gender-related beliefs of Turkish female science teachers and their effect on interactions with female and male students

Science.gov (United States)

Uysal, Sibel

The purpose of this study is to examine the relationship between Turkish female science teachers' gender-related beliefs and those teachers' corresponding interaction with their male and female students. The data was collected from five different sources: Surveys, interviews, observations, chi square data from the observation phase, and interviews with selected teachers. The data was analyzed using the Ericson interpretive method of socio-cultural theories which provided a framework for understanding the development of teacher beliefs and their interactions with their students. In this study, the survey revealed three types of teachers ranging from traditional, moderate to modern. Moderate teachers exhibited characteristics that were on a continuum between the traditional and modern teachers. Traditional teachers believed that males and females should have certain defined roles. Females should be responsible for taking care of the needs of their children and their husbands. By comparison, modern teachers did not assign specific roles to either males or females. With regard to the role of women in science, traditional teachers believed that female scientists could not be as successful as male scientists. By comparison, modern teachers believed that female scientists could be as successful as male scientists. Modern teachers did indicate that they thought females needed to work harder than males to prove themselves. When it came to the teachers' views and beliefs regarding their female and male students' success in their science classrooms, traditional teachers believed that their male students were brighter than their female students. They also believed that female students excelled only because they worked harder. Modern teachers believed that success is dependent on each student's background and his or her interest in science. Classroom observation indicated that traditional and modern teachers interacted differently with their male and female students