Evolution of complex asexual reproductive strategies in jellyfish

DEFF Research Database (Denmark)

Schnedler-Meyer, Nicolas Azaña; Pigolotti, Simone; Mariani, Patrizio

2018-01-01

Many living organisms in terrestrial and aquatic ecosystems rely on multiple reproductive strategies to reduce the risk of extinction in variable environments. Examples are provided by the polyp stage of several bloom-forming jellyfish species, which can reproduce asexually using different buddin...

Fast-slow continuum and reproductive strategies structure plant life-history variation worldwide.

Science.gov (United States)

Salguero-Gómez, Roberto; Jones, Owen R; Jongejans, Eelke; Blomberg, Simon P; Hodgson, David J; Mbeau-Ache, Cyril; Zuidema, Pieter A; de Kroon, Hans; Buckley, Yvonne M

2016-01-05

The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous variation in life history are poorly understood. We use demographic data from 418 plant species in the wild, from annual herbs to supercentennial trees, to examine how growth form, habitat, and phylogenetic relationships structure plant life histories and to develop a framework to predict population performance. We show that 55% of the variation in plant life-history strategies is adequately characterized using two independent axes: the fast-slow continuum, including fast-growing, short-lived plant species at one end and slow-growing, long-lived species at the other, and a reproductive strategy axis, with highly reproductive, iteroparous species at one extreme and poorly reproductive, semelparous plants with frequent shrinkage at the other. Our findings remain consistent across major habitats and are minimally affected by plant growth form and phylogenetic ancestry, suggesting that the relative independence of the fast-slow and reproduction strategy axes is general in the plant kingdom. Our findings have similarities with how life-history strategies are structured in mammals, birds, and reptiles. The position of plant species populations in the 2D space produced by both axes predicts their rate of recovery from disturbances and population growth rate. This life-history framework may complement trait-based frameworks on leaf and wood economics; together these frameworks may allow prediction of responses of plants to anthropogenic disturbances and changing environments.

Cancer : A reproductive strategy of "ultra-selfish" genes?

NARCIS (Netherlands)

Schuiling, GA

2004-01-01

A hypothesis is presented in which the process of "malignant transformation" which ultimately results in the rapidly dividing tumor(s)(cells) causing "cancer", is regarded as an evolved reproductive strategy of "ultra-selfish" (proto-)(onco-) genes, already present in the genome, or introduced by a

Cancer: a reproductive strategy of "ultra-selfish" genes?

Science.gov (United States)

Schuiling, G A

2004-01-01

A hypothesis is presented in which the process of "malignant transformation" which ultimately results in the rapidly dividing tumor(s)(cells) causing "cancer", is regarded as an evolved reproductive strategy of "ultra-selfish" (proto-)(onco-) genes, already present in the genome, or introduced by a virus.

Reproductive strategies in snakes.

Science.gov (United States)

Shine, Richard

2003-05-22

Snakes of both sexes display remarkable flexibility and diversity in their reproductive tactics. Many features of reproduction in female snakes (such as reproductive mode and frequency, seasonality and multiple mating) allow flexible maternal control. For example, females can manipulate not only the genotypes of their offspring (through mate choice or enhanced sperm competition) but also the phenotypes of their offspring (through allocation 'decisions', behavioural and physiological thermoregulation, and nest-site selection). Reliance on stored energy ('capital') to fuel breeding results in low frequencies of female reproduction and, in extreme cases, semelparity. A sophisticated vomeronasal system not only allows male snakes to locate reproductive females by following scent trails, but also facilitates pheromonally mediated mate choice by males. Male-male rivalry takes diverse forms, including female mimicry and mate guarding; combat bouts impose strong selection for large body size in males of some species. Intraspecific (geographical) variation and phenotypic plasticity in a wide array of reproductive traits (offspring size and number; reproductive frequency; incidence of multiple mating; male tactics such as mate guarding and combat; mate choice criteria) provide exceptional opportunities for future studies.

Niche-driven evolution of metabolic and life-history strategies in natural and domesticated populations of Saccharomyces cerevisiae

Directory of Open Access Journals (Sweden)

Sicard Delphine

2009-12-01

Full Text Available Abstract Background Variation of resource supply is one of the key factors that drive the evolution of life-history strategies, and hence the interactions between individuals. In the yeast Saccharomyces cerevisiae, two life-history strategies related to different resource utilization have been previously described in strains from different industrial origins. In this work, we analyzed metabolic traits and life-history strategies in a broader collection of yeast strains sampled in various ecological niches (forest, human body, fruits, laboratory and industrial environments. Results By analysing the genetic and plastic variation of six life-history and three metabolic traits, we showed that S. cerevisiae populations harbour different strategies depending on their ecological niches. On one hand, the forest and laboratory strains, referred to as extreme "ants", reproduce quickly, reach a large carrying capacity and a small cell size in fermentation, but have a low reproduction rate in respiration. On the other hand, the industrial strains, referred to as extreme "grasshoppers", reproduce slowly, reach a small carrying capacity but have a big cell size in fermentation and a high reproduction rate in respiration. "Grasshoppers" have usually higher glucose consumption rate than "ants", while they produce lower quantities of ethanol, suggesting that they store cell resources rather than secreting secondary products to cross-feed or poison competitors. The clinical and fruit strains are intermediate between these two groups. Conclusions Altogether, these results are consistent with a niche-driven evolution of S. cerevisiae, with phenotypic convergence of populations living in similar habitat. They also revealed that competition between strains having contrasted life-history strategies ("ants" and "grasshoppers" seems to occur at low frequency or be unstable since opposite life-history strategies appeared to be maintained in distinct ecological niches.

Reproductive health care strategy -- a gender-sensitive approach to family welfare.

Science.gov (United States)

Anita

1996-01-01

The author advocates a reproductive health care strategy to revitalize India's family welfare program. A major shift in focus is needed in population policy and programs to incorporate a gender-sensitive approach. That shift should help to clear the path toward improved health status for women and female children. Consensus reached at the UN's 1994 International Conference on Population and Development supported a change in population and development policies, affording women's empowerment, gender equality, and equity greater priority for a meaningful policy of human-centered sustainable development. Reproductive health care, reproductive health in practice, the quality of care in reproductive health, gender equality as a human right, and empowering women are discussed.

Consilience and Life History Theory: From Genes to Brain to Reproductive Strategy

Science.gov (United States)

Figueredo, Aurelio Jose; Vasquez, Geneva; Brumbach, Barbara H.; Schneider, Stephanie M. R.; Sefcek, Jon A.; Tal, Ilanit R.; Hill, Dawn; Wenner, Christopher J.; Jacobs, W. Jake

2006-01-01

We describe an integrated theory of individual differences that traces the behavioral development of life history from genes to brain to reproductive strategy. We provide evidence that a single common factor, the K-Factor, underpins a variety of life-history parameters, including an assortment of sexual, reproductive, parental, familial, and…

Reproductive strategies in snakes.

OpenAIRE

Shine, Richard

2003-01-01

Snakes of both sexes display remarkable flexibility and diversity in their reproductive tactics. Many features of reproduction in female snakes (such as reproductive mode and frequency, seasonality and multiple mating) allow flexible maternal control. For example, females can manipulate not only the genotypes of their offspring (through mate choice or enhanced sperm competition) but also the phenotypes of their offspring (through allocation 'decisions', behavioural and physiological thermoreg...

Exploiting rRNA operon copy number to investigate bacterial reproductive strategies.

Science.gov (United States)

Roller, Benjamin R K; Stoddard, Steven F; Schmidt, Thomas M

2016-09-12

The potential for rapid reproduction is a hallmark of microbial life, but microbes in nature must also survive and compete when growth is constrained by resource availability. Successful reproduction requires different strategies when resources are scarce and when they are abundant 1,2 , but a systematic framework for predicting these reproductive strategies in bacteria has not been available. Here, we show that the number of ribosomal RNA operons (rrn) in bacterial genomes predicts two important components of reproduction-growth rate and growth efficiency-which are favoured under contrasting regimes of resource availability 3,4 . We find that the maximum reproductive rate of bacteria doubles with a doubling of rrn copy number, and the efficiency of carbon use is inversely related to maximal growth rate and rrn copy number. We also identify a feasible explanation for these patterns: the rate and yield of protein synthesis mirror the overall pattern in maximum growth rate and growth efficiency. Furthermore, comparative analysis of genomes from 1,167 bacterial species reveals that rrn copy number predicts traits associated with resource availability, including chemotaxis and genome streamlining. Genome-wide patterns of orthologous gene content covary with rrn copy number, suggesting convergent evolution in response to resource availability. Our findings imply that basic cellular processes adapt in contrasting ways to long-term differences in resource availability. They also establish a basis for predicting changes in bacterial community composition in response to resource perturbations using rrn copy number measurements 5 or inferences 6,7 .

Reproductive strategy of common dentex Dentex dentex: management implications

Directory of Open Access Journals (Sweden)

A. GRAU

2016-07-01

Full Text Available Common dentex Dentex dentex is an iconic endangered species in the Mediterranean where is a sought after target species for small-scale, recreational and spearfishing fisheries. The reproductive biology of D. dentex in the natural environment is poorly known; therefore the reproductive strategy of the species was assessed by combining reproductive traits with the growth characteristics (estimated from length-at-age data, the size/age of sexual maturity and the energetic dynamics. A total of 358 wild fish were sampled on Mallorca Island (W Mediterranean from March 1996 to June 1999 with a 19 to 84.7 cm total length (LT range. The sex ratio was skewed towards females (1.361 albeit the length composition was not different between sexes (p = 0.551. Three young immature individuals (< 28 cm LT, 0.8% individuals were rudimentary hermaphrodites supporting the late gonochoristic species classification. The age composition determined from sagitta otolith interpretation ranged from 0 to 26 years (yr. Concerning growth, between sex differences in von Bertalanffy parameters were not relevant, even after accounting for potential between-year differences. The most noticeable difference was found for L∞ (64.7 cm for females versus 61.6 for males but even in this case, the bayesian credibility interval of between-sex differences included zero.  Maturity ogives at size and age showed that females achieved 50% maturity at 34.9 cm LT and 3.3 years, while males did at 33.8 cm LT and 2.5 years. The onset of gonad developing phase took place in December, while it progresses until April. The spawning peak was in April and May for both sexes. A generalized linear model showed that female size didn’t affect significantly the spawning season, whilst there was a strong seasonality in the spawning. Most of the evidences showed that fecundity is likely determinate, with an asynchronous oocyte development before spawning and a clear ovarian bimodal organization after

New regenerative braking control strategy for rear-driven electrified minivans

International Nuclear Information System (INIS)

Junzhi, Zhang; Yutong, Li; Chen, Lv; Ye, Yuan

2014-01-01

Highlights: • A regenerative braking system is designed for a rear-driven electric minivan. • A new control strategy coordinating energy efficiency and braking feel is proposed. • The control strategy is verified by simulation and hardware-in-loop (HIL) tests. • The proposed control strategy offers higher regeneration efficiency. - Abstract: As of to 2012, minivan ownership stood at 20 million units in China, accounting for 16% of the passenger car market. In this article, comprehensive research is carried out on the design and control of a regenerative braking system for a rear-driven electrified minivan. For improving the regeneration efficiency by as much as possible, a new regenerative braking control strategy called “modified control strategy” is proposed. Additionally, a control strategy called “baseline control strategy” is introduced as a comparative control strategy. Simulations and hardware-in-loop (HIL) tests are carried out. The results of the simulations and the HIL tests show that the modified control strategy offers considerably higher regeneration efficiency than the baseline control strategy. In normal deceleration braking, the regeneration efficiency of the modified control strategy reaches 47%, 15% higher than that of the baseline control strategy. In addition, improvement in the fuel economy of electric vehicles operating on the ECE driving cycle and enhanced with the modified control strategy is greater than 10%, which is 3% higher than that with the baseline control strategy

Impact of commercial farming on household reproductive strategies in Calakmul, Campeche, Mexico.

Science.gov (United States)

Gurri, Francisco D; Ortega-Muñoz, Allan

2015-01-01

The purpose of this study was to determine if commercial agriculture can lead to changes in peasant reproductive strategies in migrant agriculturalists from Calakmul, Campeche, Mexico. The reproductive histories of 746 women from Calakmul, Campeche, Mexico were collected. The sample was first divided into women who had reproduced within or outside of Calakmul (RC and RO, respectively) and these were further subdivided into those who lived in households practicing subsistence agriculture and those who turned agriculture into a business (Household Subsistence Agricultural Strategy (HSA) and Household Commercial Agricultural Strategy (HCA), respectively). Age-specific fertility rate (ASFR) differences were compared between strategies and place of reproduction. Comparisons between interbirth interval and age at which desired fertility was reached were done with a Kaplan-Meier life table-based statistic. In both strategies, RC women increased ASFRs by reducing age at first birth, and HSA-RC women also reduced interbirth intervals. HCA women had lower ASFRs than HSA women. The latter had a natural fertility pattern while the former expressed a desire to stop reproducing at a younger age. HCA-RC women showed important fertility reductions after age 25 and HCA-RO women after age 30. Fertility reductions in households that practice commercial versus those that practice subsistence agriculture were significant. Also, a "frontier" effect was observed that increased fertility over all, but HCA households were not as influenced by it. © 2015 Wiley Periodicals, Inc.

Fertility drugs, reproductive strategies and ovarian cancer risk

OpenAIRE

Tomao, Federica; Lo Russo, Giuseppe; Spinelli, Gian Paolo; Stati, Valeria; Prete, Alessandra Anna; Prinzi, Natalie; Sinjari, Marsela; Vici, Patrizia; Papa, Anselmo; Chiotti, Maria Stefania; Benedetti Panici, Pierluigi; Tomao, Silverio

2014-01-01

Several adverse effects have been related to infertility treatments, such as cancer development. In particular, the relationship between infertility, reproductive strategies, and risk of gynecological cancers has aroused much interest in recent years. The evaluation of cancer risk among women treated for infertility is very complex, mainly because of many factors that can contribute to occurrence of cancer in these patients (including parity status). This article addresses the possible associ...

Male reproductive system and spermatophores production and storage in Histioteuthis bonnellii (Cephalopoda: Histioteuthidae): A look into deep-sea squids' reproductive strategy

Science.gov (United States)

Cuccu, Danila; Mereu, Marco; Agus, Blondine; Cau, Angelo; Culurgioni, Jacopo; Sabatini, Andrea; Jereb, Patrizia

2014-09-01

Coleoid cephalopods go through a single breeding period in their life cycle, i.e., they are semelparous, although a great flexibility has been observed in their reproductive strategies, which range from simultaneous terminal spawning over a short period at the end of the animal's life to continuous spawning over a long period of the animal's life. So far, the information available on deep-sea species reproductive strategies is still poor and most of our knowledge about squid reproduction relates to females. In particular, not much is known on what strategy male squids have evolved to store sperm into spermatophores and adapt to semelparity. In this study an investigation of male reproductive strategy of the deep-sea umbrella squid Histioteuthis bonnellii (Férussac, 1835) is presented. The reproductive system was examined in 119 males caught in the Sardinian waters (Central Western Mediterranean) and is described for the first time. Results indicate that this species produces and stores spermatophores over a considerable period of time. The total number of spermatophores found in the reproductive system ranged between 12 and 3097 and the size of spermatophores stored by a single individual varied greatly, up to over 300%. Spermatophore length (SpL) gradually decreased towards the distal end of the reproductive system, so that spermatophores found in the proximal part of Needham's Sac were larger than those found in the terminal organ. Body size and SpL of spermatophores from the proximal part of Needham's Sac were positively correlated. Both indices of the sperm mass and of the ejaculatory apparatus decreased with the increase of SpL, while the cement body index increased, indicating that larger spermatophores contain less sperm and are equipped with larger cement bodies. Up to 64 spermatangia were found, exclusively in the terminal organ. The large size range of mature males (ML: 60.0-198.0 mm; TW: 113.50-2409.00 g) and the variation in spermatophore number and

Suppressing traffic-driven epidemic spreading by adaptive routing strategy

International Nuclear Information System (INIS)

Yang, Han-Xin; Wang, Zhen

2016-01-01

The design of routing strategies for traffic-driven epidemic spreading has received increasing attention in recent years. In this paper, we propose an adaptive routing strategy that incorporates topological distance with local epidemic information through a tunable parameter h. In the case where the traffic is free of congestion, there exists an optimal value of routing parameter h, leading to the maximal epidemic threshold. This means that epidemic spreading can be more effectively controlled by adaptive routing, compared to that of the static shortest path routing scheme. Besides, we find that the optimal value of h can greatly relieve the traffic congestion in the case of finite node-delivering capacity. We expect our work to provide new insights into the effects of dynamic routings on traffic-driven epidemic spreading.

Differential reproductive responses to stress reveal the role of life-history strategies within a species.

Science.gov (United States)

Schultner, J; Kitaysky, A S; Gabrielsen, G W; Hatch, S A; Bech, C

2013-11-22

Life-history strategies describe that 'slow'- in contrast to 'fast'-living species allocate resources cautiously towards reproduction to enhance survival. Recent evidence suggests that variation in strategies exists not only among species but also among populations of the same species. Here, we examined the effect of experimentally induced stress on resource allocation of breeding seabirds in two populations with contrasting life-history strategies: slow-living Pacific and fast-living Atlantic black-legged kittiwakes. We tested the hypothesis that reproductive responses in kittiwakes under stress reflect their life-history strategies. We predicted that in response to stress, Pacific kittiwakes reduce investment in reproduction compared with Atlantic kittiwakes. We exposed chick-rearing kittiwakes to a short-term (3-day) period of increased exogenous corticosterone (CORT), a hormone that is released during food shortages. We examined changes in baseline CORT levels, parental care and effects on offspring. We found that kittiwakes from the two populations invested differently in offspring when facing stress. In response to elevated CORT, Pacific kittiwakes reduced nest attendance and deserted offspring more readily than Atlantic kittiwakes. We observed lower chick growth, a higher stress response in offspring and lower reproductive success in response to CORT implantation in Pacific kittiwakes, whereas the opposite occurred in the Atlantic. Our findings support the hypothesis that life-history strategies predict short-term responses of individuals to stress within a species. We conclude that behaviour and physiology under stress are consistent with trade-off priorities as predicted by life-history theory. We encourage future studies to consider the pivotal role of life-history strategies when interpreting inter-population differences of animal responses to stressful environmental events.

The Evolution of Diapsid Reproductive Strategy with Inferences about Extinct Taxa.

Directory of Open Access Journals (Sweden)

Jason R Moore

Full Text Available Diapsids show an extremely wide range of reproductive strategies. Offspring may receive no parental care, care from only one sex, care from both parents, or care under more complex regimes. Young may vary from independent, super-precocial hatchlings to altricial neonates needing much care before leaving the nest. Parents can invest heavily in a few young, or less so in a larger number. Here we examine the evolution of these traits across a composite phylogeny spanning the extant diapsids and including the limited number of extinct taxa for which reproductive strategies can be well constrained. Generalized estimating equation(GEE-based phylogenetic comparative methods demonstrate the influences of body mass, parental care strategy and hatchling maturity on clutch volume across the diapsids. The influence of polygamous reproduction is not important despite a large sample size. Applying the results of these models to the dinosaurs supports the hypothesis of paternal care (male only in derived non-avian theropods, previously suggested based on simpler analyses. These data also suggest that sauropodomorphs did not care for their young. The evolution of parental-care occurs in an almost linear series of transitions. Paternal care rarely gives rise to other care strategies. Where hatchling condition changes, diapsids show an almost unidirectional tendency of evolution towards increased altriciality. Transitions to social monogamy from the ancestral state in diapsids, where both sexes are polygamous, are common. In contrast, once evolved, polygyny and polyandry are very evolutionarily stable. Polygyny and maternal care correlate, as do polyandry and paternal care. Ancestral-character estimation (ACE of these care strategies with the character transition likelihoods estimated from the original data gives good confidence at most important nodes. These analyses suggest that the basalmost diapsids had no parental care. Crocodilians independently evolved

Growth or reproduction: emergence of an evolutionary optimal strategy

International Nuclear Information System (INIS)

Grilli, J; Suweis, S; Maritan, A

2013-01-01

Modern ecology has re-emphasized the need for a quantitative understanding of the original ‘survival of the fittest theme’ based on analysis of the intricate trade-offs between competing evolutionary strategies that characterize the evolution of life. This is key to the understanding of species coexistence and ecosystem diversity under the omnipresent constraint of limited resources. In this work we propose an agent-based model replicating a community of interacting individuals, e.g. plants in a forest, where all are competing for the same finite amount of resources and each competitor is characterized by a specific growth–reproduction strategy. We show that such an evolution dynamics drives the system towards a stationary state characterized by an emergent optimal strategy, which in turn depends on the amount of available resources the ecosystem can rely on. We find that the share of resources used by individuals is power-law distributed with an exponent directly related to the optimal strategy. The model can be further generalized to devise optimal strategies in social and economical interacting systems dynamics. (paper)

Reproductive rights approach to reproductive health in developing countries

Directory of Open Access Journals (Sweden)

Vijayan K. Pillai

2011-12-01

Full Text Available Research on reproductive health in developing countries focuses mostly on the role of economic development on various components of reproductive health. Cross-sectional and empirical research studies in particular on the effects of non-economic factors such as reproductive rights remain few and far between.This study investigates the influence of two components of an empowerment strategy, gender equality, and reproductive rights on women's reproductive health in developing countries. The empowerment strategy for improving reproductive health is theoretically situated on a number of background factors such as economic and social development.Cross-national socioeconomic and demographic data from a number of international organizations on 142 developing countries are used to test a model of reproductive rights and reproductive health.The findings suggest that both economic and democratic development have significant positive effects on levels of gender equality. The level of social development plays a prominent role in promoting reproductive rights. It is found that reproductive rights channel the influences of social structural factors and gender equality on reproductive health.

Reproductive rights approach to reproductive health in developing countries.

Science.gov (United States)

Pillai, Vijayan K; Gupta, Rashmi

2011-01-01

Research on reproductive health in developing countries focuses mostly on the role of economic development on various components of reproductive health. Cross-sectional and empirical research studies in particular on the effects of non-economic factors such as reproductive rights remain few and far between. This study investigates the influence of two components of an empowerment strategy, gender equality, and reproductive rights on women's reproductive health in developing countries. The empowerment strategy for improving reproductive health is theoretically situated on a number of background factors such as economic and social development. Cross-national socioeconomic and demographic data from a number of international organizations on 142 developing countries are used to test a model of reproductive rights and reproductive health. The findings suggest that both economic and democratic development have significant positive effects on levels of gender equality. The level of social development plays a prominent role in promoting reproductive rights. It is found that reproductive rights channel the influences of social structural factors and gender equality on reproductive health.

Fast–slow continuum and reproductive strategies structure plant life-history variation worldwide

NARCIS (Netherlands)

Salguero-Gómez, Roberto; Jones, Owen R.; Jongejans, Eelke; Blomberg, Simon; Hodgson, D.; Zuidema, P.A.; Kroon, de Hans; Buckley, Yvonne M.

2016-01-01

The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous

The Stability Analysis and New Torque Control Strategy of Direct-Driven PMSG Wind Turbines

OpenAIRE

Jun Liu; Feihang Zhou; Gungyi Wang

2016-01-01

This paper expounds on the direct-driven PMSG wind power system control strategy, and analyses the stability conditions of the system. The direct-driven PMSG wind power system may generate the intense mechanical vibration, when wind speed changes dramatically. This paper proposes a new type of torque control strategy, which increases the system damping effectively, mitigates mechanical vibration of the system, and enhances the stability conditions of the system. The simulation results verify ...

ICT enabled education and ICT driven e-learning strategies ...

African Journals Online (AJOL)

This paper centres on ICT enabled education and ICT driven e-learning strategies: benefits and setbacks in Nigeria education system. It is in fact among the academic struggle to bring to the lime-light, the knowledge of ICT to scholars especially in the domain of education. The paper captured interesting discussion on the ...

Determining an energy-optimal thermal management strategy for electric driven vehicles

Energy Technology Data Exchange (ETDEWEB)

Suchaneck, Andre; Probst, Tobias; Puente Leon, Fernando [Karlsruher Institut fuer Technology (KIT), Karlsruhe (Germany). Inst. of Industrial Information Technology (IIIT)

2012-11-01

In electric, hybrid electric and fuel cell vehicles, thermal management may have a significant impact on vehicle range. Therefore, optimal thermal management strategies are required. In this paper a method for determining an energy-optimal control strategy for thermal power generation in electric driven vehicles is presented considering all controlled devices (pumps, valves, fans, and the like) as well as influences like ambient temperature, vehicle speed, motor and battery and cooling cycle temperatures. The method is designed to be generic to increase the thermal management development process speed and to achieve the maximal energy reduction for any electric driven vehicle (e.g., by waste heat utilization). Based on simulations of a prototype electric vehicle with an advanced cooling cycle structure, the potential of the method is shown. (orig.)

Selfish strategies and honest signalling: reproductive conflicts in ant queen associations

DEFF Research Database (Denmark)

Holman, Luke; Dreier, Stephanie; d'Ettorre, Patrizia

2010-01-01

Social insects offer unique opportunities to test predictions regarding the evolution of cooperation, life histories and communication. Colony founding by groups of unrelated queens, some of which are later killed, may select for selfish reproductive strategies, honest signalling and punishment....... Here, we use a brood transfer experiment to test whether cofounding queens of the ant Lasius niger 'selfishly' adjust their productivity when sharing the nest with future competitors. We simultaneously analysed queen cuticular hydrocarbon (CHC) profiles to investigate whether queens honestly signal...... correlated with reproductive maturation, and to a lesser extent with productivity; the same hydrocarbons were more abundant on queens that were not killed, suggesting that workers select productive queens using these chemical cues. Our results highlight the role of honest signalling in the evolution...

Reproductive rights approach to reproductive health in developing countries

OpenAIRE

Pillai, Vijayan Kumara; Gupta, Rashmi

2011-01-01

Background: Research on reproductive health in developing countries focuses mostly on the role of economic development on various components of reproductive health. Cross-sectional and empirical research studies in particular on the effects of non-economic factors such as reproductive rights remain few and far between. Objective: This study investigates the influence of two components of an empowerment strategy, gender equality, and reproductive rights on women’s reproductive health in develo...

Honey and honey-based sugars partially affect reproductive trade-offs in parasitoids exhibiting different life-history and reproductive strategies.

Science.gov (United States)

Harvey, Jeffrey A; Essens, Tijl A; Las, Rutger A; van Veen, Cindy; Visser, Bertanne; Ellers, Jacintha; Heinen, Robin; Gols, Rieta

2017-04-01

Adult dietary regimes in insects may affect egg production, fecundity and ultimately fitness. This is especially relevant in parasitoid wasps where many species serve as important biological control agents of agricultural pests. Here, we tested the effect of honey and sugar diets on daily fecundity schedules, lifetime reproductive success and longevity in four species of parasitoid wasps when reared on their respective hosts. The parasitoid species were selected based on dichotomies in host usage strategies and reproductive traits. Gelis agilis and G. areator are idiobiont ecto-parasitoids that develop in non-growing hosts, feed on protein-rich host fluids to maximize reproduction as adults and produce small numbers of large eggs. Meteorus pulchricornis and Microplitis mediator are koinobiont endoparasitoids that develop inside the bodies of growing hosts, do not host-feed, and produce greater numbers of small eggs. Parasitoids were reared on diets of either pure honey (containing trace amounts of proteins), heated honey (with denatured proteins) and a honey-mimic containing sugars only. We hypothesized that the benefits of proteins in honey would enhance reproduction in the ectoparasitoids due to their high metabolic investment per egg, but not in the koinobionts. Pure honey diet resulted in higher lifetime fecundity in G. agilis compared with the honey-mimic, whereas in both koinobionts, reproductive success did not vary significantly with diet. Longevity was less affected by diet in all of the parasitoids, although there were variable trade-offs between host access and longevity in the four species. We argue that there are both trait-based and association-specific effects of supplementary nutrients in honey on reproductive investment and success in parasitoid wasps. Copyright © 2016 Elsevier Ltd. All rights reserved.

Procedural pain management for neonates using nonpharmacological strategies: part 2: mother-driven interventions.

Science.gov (United States)

Campbell-Yeo, Marsha; Fernandes, Ananda; Johnston, Celeste

2011-10-01

This is the second of a 2-part series to provide an overview of our current level of knowledge related to nonpharmacological strategies to diminish the pain associated with commonly performed procedures in the NICU. In our first article we discussed the prevalence of repeated pain exposure in the NICU and the importance of nonpharmacological strategies specifically containment or facilitated tucking, swaddling, positioning, nonnutritive sucking, and sweet solutions. These strategies are generally nurse-driven and we believe their importance has been underutilized. In this article we will emphasize the importance of maternal presence as a mediator for pain relief. The efficacy of breastfeeding, maternal skin-to-skin care (often referred to as kangaroo care), and multisensorial stimulation such as auditory and olfactory recognition will be the primary focus of our discussion. In addition, although primarily mother-driven, these strategies are ultimately nurse-enabled, thus the importance of this connection cannot be under appreciated with respect to successful implementation in the NICU.

Partnering with public schools: a resident-driven reproductive health education initiative.

Science.gov (United States)

Kuo, Kelly; Zhu, Tao Y; Raidoo, Shandhini; Zhao, Lulu X; Sammarco, Anne; Ashby, Karen

2014-02-01

To assess the impact of a resident-driven sexual health educational initiative in an inner-city Cleveland middle school. 10 resident physicians and 57 students in 7(th) and 8(th) grade participated in this prospective cohort study. Residents taught 3 sessions on the topics of basic anatomy and physiology, pregnancy, sexually transmitted infections (STI), contraception, and safe relationships. Outcome measures included the percentages of students able to name at least 3 different STIs and contraceptive methods; to name potential complications of STIs; and to correctly identify condoms and abstinence as the only contraceptive methods also protective against STI transmission. Significant improvements were noted in students' baseline knowledge of human anatomy, contraception, and safe sex practices after completion of the curriculum. The percentage of students able to name at least 3 forms of birth control increased from 1.7% to 70.7% (P schools. The socioeconomic burden of teen pregnancy justifies comprehensive efforts to improve reproductive health education. Copyright © 2014 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

The potential of cryopreservation and reproductive technologies for animal genetic resources conservation strategies

NARCIS (Netherlands)

Hiemstra, S.J.; Lende, van der T.; Woelders, H.

2006-01-01

This chapter focuses on ex situ conservation. An overview of the state of the art cryopreservation and reproductive technology for farm animals and fish is followed by a discussion on the implications of ex situ conservation strategies. Ex situ conservation of genetic material from livestock and

Data-Driven User Feedback: An Improved Neurofeedback Strategy considering the Interindividual Variability of EEG Features.

Science.gov (United States)

Han, Chang-Hee; Lim, Jeong-Hwan; Lee, Jun-Hak; Kim, Kangsan; Im, Chang-Hwan

2016-01-01

It has frequently been reported that some users of conventional neurofeedback systems can experience only a small portion of the total feedback range due to the large interindividual variability of EEG features. In this study, we proposed a data-driven neurofeedback strategy considering the individual variability of electroencephalography (EEG) features to permit users of the neurofeedback system to experience a wider range of auditory or visual feedback without a customization process. The main idea of the proposed strategy is to adjust the ranges of each feedback level using the density in the offline EEG database acquired from a group of individuals. Twenty-two healthy subjects participated in offline experiments to construct an EEG database, and five subjects participated in online experiments to validate the performance of the proposed data-driven user feedback strategy. Using the optimized bin sizes, the number of feedback levels that each individual experienced was significantly increased to 139% and 144% of the original results with uniform bin sizes in the offline and online experiments, respectively. Our results demonstrated that the use of our data-driven neurofeedback strategy could effectively increase the overall range of feedback levels that each individual experienced during neurofeedback training.

Potential of biogenic hydrogen production for hydrogen driven remediation strategies in marine environments.

Science.gov (United States)

Hosseinkhani, Baharak; Hennebel, Tom; Boon, Nico

2014-09-25

Fermentative production of bio-hydrogen (bio-H2) from organic residues has emerged as a promising alternative for providing the required electron source for hydrogen driven remediation strategies. Unlike the widely used production of H2 by bacteria in fresh water systems, few reports are available regarding the generation of biogenic H2 and optimisation processes in marine systems. The present research aims to optimise the capability of an indigenous marine bacterium for the production of bio-H2 in marine environments and subsequently develop this process for hydrogen driven remediation strategies. Fermentative conversion of organics in marine media to H2 using a marine isolate, Pseudoalteromonas sp. BH11, was determined. A Taguchi design of experimental methodology was employed to evaluate the optimal nutritional composition in batch tests to improve bio-H2 yields. Further optimisation experiments showed that alginate-immobilised bacterial cells were able to produce bio-H2 at the same rate as suspended cells over a period of several weeks. Finally, bio-H2 was used as electron donor to successfully dehalogenate trichloroethylene (TCE) using biogenic palladium nanoparticles as a catalyst. Fermentative production of bio-H2 can be a promising technique for concomitant generation of an electron source for hydrogen driven remediation strategies and treatment of organic residue in marine ecosystems. Copyright © 2014 Elsevier B.V. All rights reserved.

Data-Driven User Feedback: An Improved Neurofeedback Strategy considering the Interindividual Variability of EEG Features

Directory of Open Access Journals (Sweden)

Chang-Hee Han

2016-01-01

Full Text Available It has frequently been reported that some users of conventional neurofeedback systems can experience only a small portion of the total feedback range due to the large interindividual variability of EEG features. In this study, we proposed a data-driven neurofeedback strategy considering the individual variability of electroencephalography (EEG features to permit users of the neurofeedback system to experience a wider range of auditory or visual feedback without a customization process. The main idea of the proposed strategy is to adjust the ranges of each feedback level using the density in the offline EEG database acquired from a group of individuals. Twenty-two healthy subjects participated in offline experiments to construct an EEG database, and five subjects participated in online experiments to validate the performance of the proposed data-driven user feedback strategy. Using the optimized bin sizes, the number of feedback levels that each individual experienced was significantly increased to 139% and 144% of the original results with uniform bin sizes in the offline and online experiments, respectively. Our results demonstrated that the use of our data-driven neurofeedback strategy could effectively increase the overall range of feedback levels that each individual experienced during neurofeedback training.

Reproductive allocation strategies in desert and Mediterranean populations of annual plants grown with and without water stress.

Science.gov (United States)

Aronson, J; Kigel, J; Shmida, A

1993-03-01

Reproductive effort (relative allocation of biomass to diaspore production) was compared in matched pairs of Mediterranean and desert populations of three unrelated annual species, Erucaria hispanica (L.) Druce, Bromus fasciculatus C. Presl. and Brachypodium distachyon (L.) Beauv., grown under high and low levels of water availability in a common-environment experiment. Desert populations in all three species showed higher reproductive effort than corresponding Mediterranean populations, as expressed by both a reproductive index (RI= reproductive biomass/vegetative biomass), and a reproductive efficiency index (REI=number of diaspores/total plant biomass). Moreover, in E. hispanica and Brachypodium distachyon, inter-populational differences in reproductive effort were greater under water stress, the main limiting factor for plant growth in the desert. These results indicate that variability in reproductive effort in response to drought is a critical and dynamic component of life history strategies in annual species in heterogeneous, unpredictable xeric environments. When subjected to water stress the Mediterranean populations of E. hispanica and B. distachyon showed greater plasticity (e.g. had a greater reduction) in reproductive effort than the desert populations, while in Bromus fasciculatus both populations showed similar amounts of plasticity.

The role of fecundity and reproductive effort in defining life-history strategies of North American freshwater mussels.

Science.gov (United States)

Haag, Wendell R

2013-08-01

Selection is expected to optimize reproductive investment resulting in characteristic trade-offs among traits such as brood size, offspring size, somatic maintenance, and lifespan; relative patterns of energy allocation to these functions are important in defining life-history strategies. Freshwater mussels are a diverse and imperiled component of aquatic ecosystems, but little is known about their life-history strategies, particularly patterns of fecundity and reproductive effort. Because mussels have an unusual life cycle in which larvae (glochidia) are obligate parasites on fishes, differences in host relationships are expected to influence patterns of reproductive output among species. I investigated fecundity and reproductive effort (RE) and their relationships to other life-history traits for a taxonomically broad cross section of North American mussel diversity. Annual fecundity of North American mussel species spans nearly four orders of magnitude, ranging from 200000). Estimates of RE also were highly variable, ranging among species from 0.06 to 25.4%. Median fecundity and RE differed among phylogenetic groups, but patterns for these two traits differed in several ways. For example, the tribe Anodontini had relatively low median fecundity but had the highest RE of any group. Within and among species, body size was a strong predictor of fecundity and explained a high percentage of variation in fecundity among species. Fecundity showed little relationship to other life-history traits including glochidial size, lifespan, brooding strategies, or host strategies. The only apparent trade-off evident among these traits was the extraordinarily high fecundity of Leptodea, Margaritifera, and Truncilla, which may come at a cost of greatly reduced glochidial size; there was no relationship between fecundity and glochidial size for the remaining 61 species in the dataset. In contrast to fecundity, RE showed evidence of a strong trade-off with lifespan, which was

How to develop a theory-driven evaluation design? Lessons learned from an adolescent sexual and reproductive health programme in West Africa.

Science.gov (United States)

Van Belle, Sara B; Marchal, Bruno; Dubourg, Dominique; Kegels, Guy

2010-11-30

This paper presents the development of a study design built on the principles of theory-driven evaluation. The theory-driven evaluation approach was used to evaluate an adolescent sexual and reproductive health intervention in Mali, Burkina Faso and Cameroon to improve continuity of care through the creation of networks of social and health care providers. Based on our experience and the existing literature, we developed a six-step framework for the design of theory-driven evaluations, which we applied in the ex-post evaluation of the networking component of the intervention. The protocol was drafted with the input of the intervention designer. The programme theory, the central element of theory-driven evaluation, was constructed on the basis of semi-structured interviews with designers, implementers and beneficiaries and an analysis of the intervention's logical framework. The six-step framework proved useful as it allowed for a systematic development of the protocol. We describe the challenges at each step. We found that there is little practical guidance in the existing literature, and also a mix up of terminology of theory-driven evaluation approaches. There is a need for empirical methodological development in order to refine the tools to be used in theory driven evaluation. We conclude that ex-post evaluations of programmes can be based on such an approach if the required information on context and mechanisms is collected during the programme.

Sex-linked strategies of human reproductive behavior.

Science.gov (United States)

Jaffe, K; Urribarri, D; Chacon, G C; Diaz, G; Torres, A; Herzog, G

1993-01-01

We present data on fertility characteristics in the Venezuelan population for each sex separately, allowing a detailed comparative analysis of the variance in fertility between males and females. We show that the fertility distribution for both sexes is discontinuous, that the average female has a larger number of offspring per individual than the average male, and that highly fertile males outnumber highly fertile females so that the total number of offspring produced by males and females is balanced. Results indicate that a few males are responsible for a relative higher fertility of the average female and that interactions between polyandric females with monogamic and polygynic males are common. Among the Yanomami, a relatively unacculturated hunter-gatherer-horticulturist tribe, similar differences in fertility distribution of both sexes are apparent. The data suggest that human populations contain statistically distinct subpopulations, with different reproductive strategies, suggesting the existence of complex interactions among human populations which are not evident from the study of individuals or groups.

Comparative analysis of the reproductive strategy of lion's paw scallop Nodipecten subnodosus in Baja California Sur, Mexico

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Marco A Angel-Dapa

2015-07-01

Full Text Available The reproductive strategy of lion's paw scallop Nodipecten subnodosus was evaluated in a culturing system in Bahía Tortugas, Baja California Sur, Mexico during an annual cycle, comparing its response with data previously reported at other localities. High frequencies of ripe gonads throughout the year indicate that reproduction was continuous, with two main ripening/spawning events: July-September and December-March. A continuous breeding is also reported for the species in Bahía Magdalena, Bahía Juncalito, and Bahía de Los Angeles. These eutrophic areas are Biological Active Centers where gametogenesis appears to be regulated by the energy taken from recently ingested food following an opportunistic strategy. However, the digestive gland index decreased and the muscle indices increased during one of the breeding peaks, suggesting that some stored reserves are also used to sustain gametogenesis (conservative strategy partially. High incidences of atretic oocytes are likely associated with atypical daily variations in water temperature from May through September (12 to 33°C, or with stressful conditions in the culturing system in summer. Despite this, the culturing system set in Bahía Tortugas appears beneficial for a continuous reproduction of N. subnodosus.

Correlated seed failure as an environmental veto to synchronize reproduction of masting plants.

Science.gov (United States)

Bogdziewicz, Michał; Steele, Michael A; Marino, Shealyn; Crone, Elizabeth E

2018-07-01

Variable, synchronized seed production, called masting, is a widespread reproductive strategy in plants. Resource dynamics, pollination success, and, as described here, environmental veto are possible proximate mechanisms driving masting. We explored the environmental veto hypothesis, which assumes that reproductive synchrony is driven by external factors preventing reproduction in some years, by extending the resource budget model of masting with correlated reproductive failure. We ran this model across its parameter space to explore how key parameters interact to drive seeding dynamics. Next, we parameterized the model based on 16 yr of seed production data for populations of red (Quercus rubra) and white (Quercus alba) oaks. We used these empirical models to simulate seeding dynamics, and compared simulated time series with patterns observed in the field. Simulations showed that resource dynamics and reproduction failure can produce masting even in the absence of pollen coupling. In concordance with this, in both oaks, among-year variation in resource gain and correlated reproductive failure were necessary and sufficient to reproduce masting, whereas pollen coupling, although present, was not necessary. Reproductive failure caused by environmental veto may drive large-scale synchronization without density-dependent pollen limitation. Reproduction-inhibiting weather events are prevalent in ecosystems, making described mechanisms likely to operate in many systems. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust.

Design Driven Innovation as a Differentiation Strategy - in the Context of Automotive Industry

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Mosarrat Farhana

2015-07-01

Full Text Available Though, in the automotive industry, technology is considered as a source of innovation and development, emerging change in consumer perception has brought industry focus on design. Evolution of this industry is closely related to the convergence of technology and design. In such context, implication of design driven innovation strategy in the automotive industry has potential to be explored and to create sustained competitive advantage through balancing customers’ need, technological opportunities and product meaning. The aim of this paper is to give a holistic view of design driven innovation as a differentiation strategy in the automotive industry and its implication for strategic management through some relevant research reviews and empirical information. On the contrary, this research lacks detailed description on industry practice to provide greater breadth, since it attempts to correlate the strategic concept of design with the dynamic capability of a firm in that particular industry.

Improvement of Adolescent Reproductive Health Understanding by Implementation of Educative, Collaborative, Participative, and Problem Based (ECPPB Learning Strategy in Buleleng District, Bali-Indonesia

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Desak Made Citrawathi

2016-10-01

Full Text Available Introduction: One of potential public health issues in Indonesia is the problem of Adolescent Reproduction Health (ARH, particulary the behavior of having sex premaritaly and promiscuity, which is at risk of having unwanted pregnancy and sexually transmitted deseases such as HIV/AIDS. Increase in student’s knowledge, attitude, and skill by application of education of adolescent reproduction health (EARHis hopefully  will reduce the ARH problem.Method: This was experimental research with randomized pretest-posttest control group design. This research was conducted in Grade VIII of Junior High School with 72 research samples. Data were analysed by using Multivariate Analysis of Variances (Manova. Result: Data analysis showed that ECPPB learning strategy was better to improve students’ knowledge ARH, students’ attitude toward reproduction health, and students’ skill in ARH problem solving than students who were treated by using conventional teaching strategy in which the p = 0.0001(p < 0,05. The Partial Ata Squared (PTA was 87.4 %, which means the learning strategy was able to improve learning achievement as much as 87.4 %. The highest improvement of learning achievement by using ECPPBlearning strategy was on students’ skill in ARH problem solving (PES=80.9%. Improvement of health reproduction attitude was 63.2 %, and improvement of students’ knowledge about reproduction health was 25.1%. Conclusion: Based on the result of this study was suggested in order to students be given EARH was integrated on the subject of science in junior high school by using ECPPB strategy.

Fertility drugs, reproductive strategies and ovarian cancer risk.

Science.gov (United States)

Tomao, Federica; Lo Russo, Giuseppe; Spinelli, Gian Paolo; Stati, Valeria; Prete, Alessandra Anna; Prinzi, Natalie; Sinjari, Marsela; Vici, Patrizia; Papa, Anselmo; Chiotti, Maria Stefania; Benedetti Panici, Pierluigi; Tomao, Silverio

2014-01-01

Several adverse effects have been related to infertility treatments, such as cancer development. In particular, the relationship between infertility, reproductive strategies, and risk of gynecological cancers has aroused much interest in recent years. The evaluation of cancer risk among women treated for infertility is very complex, mainly because of many factors that can contribute to occurrence of cancer in these patients (including parity status). This article addresses the possible association between the use of fertility treatments and the risk of ovarian cancer, through a scrupulous search of the literature published thus far in this field. Our principal objective was to give more conclusive answers on the question whether the use of fertility drug significantly increases ovarian cancer risk. Our analysis focused on the different types of drugs and different treatment schedules used. This study provides additional insights regarding the long-term relationships between fertility drugs and risk of ovarian cancer.

REPRODUCTIVE SEASONALITY AND ITS CONTROL IN SPANISH SHEEP AND GOATS

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Amelia Gómez Brunet

2011-12-01

Full Text Available Sheep and goat breeds from subtropical, middle and high latitudes show seasonal changes in reproductive activity. In general, the breeding season starts in autumn and ends in winter, with anoestrus in spring/summer. An endogenous circannual rhythm driven and synchronised by the annual photoperiod cycle regulates the onset and offset of the breeding season. However, the timing and duration of the breeding season can be affected by interactions between the photoperiod and factors such as breed, geographical origin, nutritional and lactational status, social interactions, and the season of parturition. Seasonality in reproduction is naturally accompanied by variation in the availability and price of meat, milk and cheese over the year, affecting the economy of farmers, consumers and the food industry alike. The control of reproduction outside the normal breeding season by inducing and synchronizing oestrus and ovulation plus the use of artificial insemination and/or natural mating would help ensure the year-round availability of products. This review describes the seasonal variation in the sexual activity of ovine and caprine species with special regard to local Spanish sheep and goats breeds, examines how the photoperiod regulates their annual reproductive cycle, and discusses a number of strategies that can be used to induce and synchronise ovulation outside the natural breeding season.

Reproductive strategies of two sympatric "small barbs" (Barbus humilis and B. tanapelagius, Cyprinidae) in Lake Tana

NARCIS (Netherlands)

Dejen, E.; Sibbing, F.A.; Vijverberg, J.

2003-01-01

The reproductive strategies of two species of 'small barbs' (12,000 fish). Both species have a long breeding period (from March to September), and the distinct bimodal size-frequency distributions of eggs suggest multiple spawning for both species. Absolute fecundity increased exponentially with

Sensor-Based Model Driven Control Strategy for Precision Irrigation

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Camilo Lozoya

2016-01-01

Full Text Available Improving the efficiency of the agricultural irrigation systems substantially contributes to sustainable water management. This improvement can be achieved through an automated irrigation system that includes a real-time control strategy based on the water, soil, and crop relationship. This paper presents a model driven control strategy applied to an irrigation system, in order to make an efficient use of water for large crop fields, that is, applying the correct amount of water in the correct place at the right moment. The proposed model uses a predictive algorithm that senses soil moisture and weather variables, to determine optimal amount of water required by the crop. This proposed approach is evaluated against a traditional irrigation system based on the empirical definition of time periods and against a basic soil moisture control system. Results indicate that the use of a model predictive control in an irrigation system achieves a higher efficiency and significantly reduce the water consumption.

Environmental contingency in life history strategies: the influence of mortality and socioeconomic status on reproductive timing.

Science.gov (United States)

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

2011-02-01

Why do some people have children early, whereas others delay reproduction? By considering the trade-offs between using one's resources for reproduction versus other tasks, the evolutionary framework of life history theory predicts that reproductive timing should be influenced by mortality and resource scarcity. A series of experiments examined how mortality cues influenced the desire to have children sooner rather than later. The effects of mortality depended critically on whether people grew up in a relatively resource-scarce or resource-plentiful environment. For individuals growing up relatively poor, mortality cues produced a desire to reproduce sooner--to want children now, even at the cost of furthering one's education or career. Conversely, for individuals growing up relatively wealthy, mortality cues produced a desire to delay reproduction--to further one's education or career before starting a family. Overall, mortality cues appear to shift individuals into different life history strategies as a function of childhood socioeconomic status, suggesting important implications for how environmental factors can influence fertility and family size. (PsycINFO Database Record (c) 2010 APA, all rights reserved).

Multiple reproductive strategies in a tropical hover wasp

DEFF Research Database (Denmark)

Fanelli, D.; Boomsma, Jacobus Jan; Turillazzi, S.

2005-01-01

Reproductive skew theory has been an important component of efforts to design a unifying theory of social evolution, as it aims to explain patterns of reproductive partitioning in animal societies as a function of relatedness, group productivity, fighting ability and ecological constraints on ind...

Fast-slow continuum and reproductive strategies structure plant life-history variation worldwide

DEFF Research Database (Denmark)

Salguero-Gómez, Roberto; Jones, Owen R; Jongejans, Eelke

2016-01-01

The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous...... variation in life history are poorly understood. We use demographic data from 418 plant species in the wild, from annual herbs to supercentennial trees, to examine how growth form, habitat, and phylogenetic relationships structure plant life histories and to develop a framework to predict population...

Reproductive strategies in males of the world's southernmost lizards.

Science.gov (United States)

Fernández, Jimena B; Medina, Marlin; Kubisch, Erika L; Scolaro, José A; Ibargüengoytía, Nora R

2017-03-01

Reproductive and life history patterns in reptiles are tightly related to the environmental conditions, so male reproductive cycles have been historically characterized as continuous, for tropical lizards, or seasonal, for temperate lizards. However, males of Liolaemus and Phymaturus lizards (Liolaemidae), from cold temperate climates of high altitudes or latitudes in Argentina and Chile, have developed a variety of reproductive cycles to coordinate with the short female reproductive season and to deal with the low frequency of reproductive females in the population. Using gonadal histology and morphological analysis, we describe the male reproductive biology, fat storage and sexual dimorphism of the viviparous lizards Liolaemus sarmientoi and Liolaemus magellanicus that inhabit an austral grass steppe at 51°S, in the southern limit of the American continent. Males of L. sarmientoi and L. magellanicus are reproductively available during the entire activity season of approximately 5 months. In addition, males of both species exhibit greater body sizes than females in morphological variables relevant in sexual selection. Meanwhile, females of both species exhibit larger inter-limb length than conspecific males, which suggests fecundity selection to increase space for a larger litter size. The continuous sperm production throughout the activity season allows these liolaemids to mate at any time when females ovulate, representing a selective advantage to deal with the short activity season and the adversities of the cold environment they inhabit. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

Breeds of risk-adjusted fundamentalist strategies in an order-driven market

Science.gov (United States)

LiCalzi, Marco; Pellizzari, Paolo

2006-01-01

This paper studies an order-driven stock market where agents have heterogeneous estimates of the fundamental value of the risky asset. The agents are budget-constrained and follow a value-based trading strategy which buys or sells depending on whether the price of the asset is below or above its risk-adjusted fundamental value. This environment generates returns that are remarkably leptokurtic and fat-tailed. By extending the study over a grid of different parameters for the fundamentalist trading strategy, we exhibit the existence of monotone relationships between the bid-ask spread demanded by the agents and several statistics of the returns. We conjecture that this effect, coupled with positive dependence of the risk premium on the volatility, generates positive feedbacks that might explain volatility bursts.

Reproductive strategies of two sympatric 'small barbs'(Barbus humilis and B. tanapelagius, Cyprinidae)in Lake Tana, Ethiopia

NARCIS (Netherlands)

Dejen, E.; Sibbing, F.A.; Vijverberg, J.

2003-01-01

The reproductive strategies of two species of 'small barbs' (12,000 fish). Both species have a long breeding period (from March to September), and the distinct bimodal size-frequency distributions of eggs suggest multiple spawning for both species. Absolute fecundity increased exponentially with

The Cook, the Thief, his Wife and her Lovert : on the evolution of the human reproductive strategy

NARCIS (Netherlands)

Schuiling, GA

2003-01-01

Human reproductive strategy differs from that of most other mammals, including Apes such as the closely related chimpanzee (Pan troglodytes) and the bonobo (Pan paniscus). For example, humans, although basically polygamic, exhibit a strong tendency to (serial) monogamy and-very rare for a

Male reproductive health challenges: appraisal of wives coping strategies.

Science.gov (United States)

Amoo, Emmanuel O; Omideyi, Adekunbi K; Fadayomi, Theophilus O; Ajayi, Mofoluwake P; Oni, Gbolahan A; Idowu, Adenike E

2017-07-28

Systematic studies on the association between men's sexual dysfunction (low sexual desire, ejaculation disorders, erectile dysfunctions, genital ulcers, testicular disorders, prostate cancer or sexually transmitted infections) and marital conflict are emerging. However, the coping strategies adopted by wives in such circumstances are not commonly reported in the literature. Male sexual functioning is vital to the marital relationship, lack of it can result in intolerable cohabitation or relationship breakdown, and could also cause infertility, infidelity, and arouse stigma in Nigeria. The understanding of coping strategies by female partners could guide in the counselling and treatment of men's sexual health problems. Effective coping has the potential to lessen or prevent negative outcomes, and thereby could reduce marital conflict. This study examined the coping strategies adopted by women whose husbands have reproductive health challenges in two of the five states with the highest proportion of divorce/separation in Nigeria. Four focus group discussions were conducted in two local government areas. The women were recruited from a quantitative couple-study for men with sexual health problems. Focus group responses were transcribed and analysed using systematic-content-analysis with thematic organisation of the summaries and systematic typologies of participants' responses. The results revealed the coping strategies employed by women in this environment: seeking guidance from their religious leaders and family doctors, physical-sexual-therapy, abstinence and concubinage. The participants indicated that they encountered difficulties in discussing their husbands' sexual health problems with a third party. The study concludes that husband's sexual ability is crucial to the sustenance of the marital relationship. Religious leaders and family doctors often serve as mediators to husband-wife conflict management. Counselling is recommended in cases of sexual health

Reproductive efficiency and shade avoidance plasticity under simulated competition

OpenAIRE

Fazlioglu, Fatih; Al?Namazi, Ali; Bonser, Stephen P.

2016-01-01

Abstract Plant strategy and life?history theories make different predictions about reproductive efficiency under competition. While strategy theory suggests under intense competition iteroparous perennial plants delay reproduction and semelparous annuals reproduce quickly, life?history theory predicts both annual and perennial plants increase resource allocation to reproduction under intense competition. We tested (1) how simulated competition influences reproductive efficiency and competitiv...

Reproductive strategies, karyology, parasites, and taxonomic status of Dugesia populations from Yemen (Platyhelminthes: Tricladida: Dugesiidae).

Science.gov (United States)

Harrath, Abdul Halim; Sluys, Ronald; Aldahmash, Waleed; Al-Razaki, Abdulkarim; Alwasel, Saleh

2013-06-01

We present new data on the distribution, reproductive strategies, karyology, and taxonomic status of populations of freshwater planarians from Yemen. Nine populations were sampled and significant differences in their reproductive strategies and karyology are reported. The present study presents the first fully documented record of a naturally sexual, diploid (2n = 18) population of a Dugesia species in the eastern part of the Afrotropical region. Morphological characters combined with karyological data suggest that these Dugesia populations from Yemen represent a new species, which is herein described as Dugesia arabica Harrath and Sluys, sp. nov. This new species is mainly distinguishable from other Dugesia species that are distributed exclusively in the Mediterranean basin and in the eastern part of the Afrotropical region by the presence of the following features: well-developed and cone-shaped penis papilla, housing an ejaculatory duct that runs ventrally and has a subterminal and ventral opening; a considerably expanded and folded section of the bursal canal at the level of the oviducal openings; absence of a layer of longitudinal muscles on the copulatory bursa and the bursal canal. Specimens from two populations from Yemen were infested with a gregarine Protozoon.

'Man Up': the importance and strategy for placing male reproductive health centre stage in the political and research agenda.

Science.gov (United States)

Barratt, Christopher L R; De Jonge, Christopher J; Sharpe, Richard M

2018-04-01

Approximately 1 in 20 young men today have sperm counts low enough to impair fertility, whereas this may not have been the case historically. The cause(s) of such a decline in male reproductive health is unknown, despite it being a global health issue. Concomitantly, little progress has been made in answering fundamental questions in andrology or in developing new diagnostic tools or alternative management strategies to ICSI in infertile men. We advocate formulation of a detailed roadmap for male reproductive health to facilitate development of a research agenda that highlights the present unmet needs and key unanswered questions, and seeks to deliver effective funding and investment to address them. This vision we term 'a Male Reproductive Health Ecosystem'.

Peasant reproduction and local knowledge in contexts of social and environmental fragility. Family and community strategies in the mountain range of Tentzo, México

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Beatriz Martínez Corona

2016-09-01

Full Text Available The article presents results of research conducted in the city of San Antonio Juarez, Tzicatlacoyan township, in the state of Puebla, Mexico. The objective was to determine the reproductive strategies of domestic groups peasants, facing adverse environmental conditions that severely restrict the development of agriculture. From qualitative and quantitative techniques, it was found the presence of different reproduction strategies, at the neighborhood level, based on local knowledge, the gender division of labor and domestic level organization and community group.

Resources allocation in reproductive rabbit does: a review of feeding and genetic strategies for suitable performance

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Juan José Pascual

2013-09-01

Full Text Available In the present work is analysed how frequent feeding and selection programmes could be affecting resources allocation in reproductive rabbit does, and the possible consequences resulted from these changes, as well as the central role of body condition for a suitable female performance considering genetic level, health and welfare.  Resources allocation between functions, and consequently body condition, must be genetically driven.  Traditional view of body reserves mobilisation in reproductive rabbit does as a response of feed intake must be moved to an animal view, where feed intake must be considered more as an “output” consequence of the resources allocation in the female to ensure current and future litter viability.  To a great extent, future reproductive potential of reproductive rabbit females is decided before first partum.  There seems to be enough evidence of a possible threshold for the rabbit female birth weight to reach the beginning of reproductive life in a suitable body condition to maximise their future reproductive potential.  The moment of first mating could be identified the last ‘pure’ data of the animal, sign of the animal soma and probably related to their productive potential.  The choice of an adequate feeding system during rearing and first pregnancy also seems to be relevant in the reproductive performance of rabbit females in the short and long term. This should allow young females to reach first mating and late pregnancy with a good maturity level, but over-fattening must be avoided to reduce the risk of pregnancy toxaemia and reduced reproduction.  The body condition of the females changes during the reproductive cycle and throughout their reproductive life according to their genetically determined level.  The problems appear when the animals are forced to differ from this adequate level, increasing susceptibility to disease, other stress factors and eventual failure.  The body condition of young

Model-based optimization strategy of chiller driven liquid desiccant dehumidifier with genetic algorithm

International Nuclear Information System (INIS)

Wang, Xinli; Cai, Wenjian; Lu, Jiangang; Sun, Youxian; Zhao, Lei

2015-01-01

This study presents a model-based optimization strategy for an actual chiller driven dehumidifier of liquid desiccant dehumidification system operating with lithium chloride solution. By analyzing the characteristics of the components, energy predictive models for the components in the dehumidifier are developed. To minimize the energy usage while maintaining the outlet air conditions at the pre-specified set-points, an optimization problem is formulated with an objective function, the constraints of mechanical limitations and components interactions. Model-based optimization strategy using genetic algorithm is proposed to obtain the optimal set-points for desiccant solution temperature and flow rate, to minimize the energy usage in the dehumidifier. Experimental studies on an actual system are carried out to compare energy consumption between the proposed optimization and the conventional strategies. The results demonstrate that energy consumption using the proposed optimization strategy can be reduced by 12.2% in the dehumidifier operation. - Highlights: • Present a model-based optimization strategy for energy saving in LDDS. • Energy predictive models for components in dehumidifier are developed. • The Optimization strategy are applied and tested in an actual LDDS. • Optimization strategy can achieve energy savings by 12% during operation

Social context and reproductive potential affect worker reproductive decisions in a eusocial insect.

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Boris Yagound

Full Text Available Context-dependent decision-making conditions individual plasticity and is an integrant part of alternative reproductive strategies. In eusocial Hymenoptera (ants, bees and wasps, the discovery of worker reproductive parasitism recently challenged the view of workers as a homogeneous collective entity and stressed the need to consider them as autonomous units capable of elaborate choices which influence their fitness returns. The reproductive decisions of individual workers thus need to be investigated and taken into account to understand the regulation of reproduction in insect societies. However, we know virtually nothing about the proximate mechanisms at the basis of worker reproductive decisions. Here, we test the hypothesis that the capacity of workers to reproduce in foreign colonies lies in their ability to react differently according to the colonial context and whether this reaction is influenced by a particular internal state. Using the bumble bee Bombus terrestris, we show that workers exhibit an extremely high reproductive plasticity which is conditioned by the social context they experience. Fertile workers reintroduced into their mother colony reverted to sterility, as expected. On the contrary, a high level of ovary activity persisted in fertile workers introduced into a foreign nest, and this despite more frequent direct contacts with the queen and the brood than control workers. Foreign workers' reproductive decisions were not affected by the resident queen, their level of fertility being similar whether or not the queen was removed from the host colony. Workers' physiological state at the time of introduction is also of crucial importance, since infertile workers failed to develop a reproductive phenotype in a foreign nest. Therefore, both internal and environmental factors appear to condition individual reproductive strategies in this species, suggesting that more complex decision-making mechanisms are involved in the regulation

Long-term consequences of disturbances on reproductive strategies of the rare epiphytic lichen Lobaria pulmonaria: clonality a gift and a curse

OpenAIRE

Singh, Garima; Dal Grande, Francesco; Werth, Silke; Scheidegger, Christoph

2017-01-01

The effect of disturbance on symbiotic organisms such as lichens is particularly severe. In case of heterothallic lichen-forming fungi, disturbances may lead to unbalanced gene frequency and patchy distribution of mating types, thus inhibiting sexual reproduction and imposing clonality. The impact of disturbance on reproductive strategies and genetic diversity of clonal systems has so far received little attention. To infer the effects of disturbances on mating-type allele frequencies and pop...

Grandparental effects on reproductive strategizing

Directory of Open Access Journals (Sweden)

2004-09-01

Full Text Available This paper analyzes data from the household registers for two villages in the Nôbi region of central Japan in the late Edo period (1717-1869 to assess how grandparents may have affected reproductive strategizing in stem families. The particulars of the family system fostered a culturally favored set of reproductive goals, in particular, a daughter as eldest child, followed by a son (and heir, coupled with gender alternation in subsequent reproduction and overall gender balance. This reproductive strategy was generally followed during the stem phase of the domestic cycle, when one or both grandparents were present, especially when the family head was in the senior generation. By contrast, a son-first strategy was favored when childbearing began in the conjugal phase of the cycle. This suggests grandparental influence on the junior couple's reproductive decisions in favor of the cultural ideal. I find that the senior couple's decision to marry the heir early or late strongly affects the reproductive strategies followed by him after marriage. I show that when a grandmother is present at the onset of childbearing, especially if she is relatively young, the junior couple ends up with more offspring on average. A controlled analysis of infanticiding behavior is interpreted in terms of conjugal power and coalition formation. It appears that a grandmother gets her way only when she and her son gang up on the daughter-in-law, but such a coalition is likely only when her son dominates the conjugal relationship (which in turn reflects the grandmother's success in binding the son tightly to her emotionally and in delaying his marriage. Otherwise, the grandmother may be shut out from reproductive decision-making by the solidary conjugal coalition.

Operationalising sexual and reproductive health and rights in sub-Saharan Africa: constraints, dilemmas and strategies

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Oronje Rose

2011-12-01

Full Text Available Abstract Background The continued poor sexual and reproductive health (SRH outcomes in sub-Saharan Africa highlight the difficulties in reforming policies and laws, and implementing effective programmes. This paper uses one international and two national case studies to reflect on the challenges, dilemmas and strategies used in operationalising sexual and reproductive health and rights (SRHR in different African contexts. Methods The international case study focuses on the progress made by African countries in implementing the African Union’s Maputo Plan of Action (for the Operationalisation of the Continental Policy Framework for Sexual and Reproductive Health and Rights and the experiences of state and non-state stakeholders in this process. The case was developed from an evaluation report of the progress made by nine African countries in implementing the Plan of Action, qualitative interviews exploring stakeholders’ experiences and perceptions of the operationalisation of the plan (carried out as part of the evaluation in Botswana and Nigeria, and authors’ reflections. The first national case study explores the processes involved in influencing Ghana’s Domestic Violence Act passed in 2007; developed from a review of scientific papers and organisational publications on the processes involved in influencing the Act, qualitative interview data and authors’ reflections. The second national case study examines the experiences with introducing the 2006 Sexual Offences Act in Kenya, and it is developed from organisational publications on the processes of enacting the Act and a review of media reports on the debates and passing of the Act. Results Based on the three cases, we argue that prohibitive laws and governments’ reluctance to institute and implement comprehensive rights approaches to SRH, lack of political leadership and commitment to funding SRHR policies and programmes, and dominant negative cultural framing of women’s issues

Reproductive success and failure: the role of winter body mass in reproductive allocation in Norwegian moose.

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Milner, Jos M; van Beest, Floris M; Solberg, Erling J; Storaas, Torstein

2013-08-01

A life history strategy that favours somatic growth over reproduction is well known for long-lived iteroparous species, especially in unpredictable environments. Risk-sensitive female reproductive allocation can be achieved by a reduced reproductive effort at conception, or the subsequent adjustment of investment during gestation or lactation in response to unexpected environmental conditions or resource availability. We investigated the relative importance of reduced investment at conception compared with later in the reproductive cycle (i.e. prenatal, perinatal or neonatal mortality) in explaining reproductive failure in two high-density moose (Alces alces) populations in southern Norway. We followed 65 multiparous, global positioning system (GPS)-collared females throughout the reproductive cycle and focused on the role of maternal nutrition during gestation in determining reproductive success using a quasi-experimental approach to manipulate winter forage availability. Pregnancy rates in early winter were normal (≥0.8) in all years while spring calving rates ranged from 0.4 to 0.83, with prenatal mortality accounting for most of the difference. Further losses over summer reduced autumn recruitment rates to 0.23-0.69, despite negligible predation. Over-winter mass loss explained variation in both spring calving and autumn recruitment success better than absolute body mass in early or late winter. Although pregnancy was related to body mass in early winter, overall reproductive success was unrelated to pre-winter body condition. We therefore concluded that reproductive success was limited by winter nutritional conditions. However, we could not determine whether the observed reproductive allocation adjustment was a bet-hedging strategy to maximise reproduction without compromising survival or whether females were simply unable to invest more resources in their offspring.

Reproductive Strategy of the Polyploid Species Varronia curassavica Jacq. in Restinga Environment.

Science.gov (United States)

Hoeltgebaum, Marcia Patricia; Londoño, Diana Marcela Morales; Lando, Ana Paula; Dos Reis, Maurício Sedrez

2017-06-01

This study aimed to elucidate the breeding strategies of Varronia curassavica, an important medicinal species associated with Brazilian restinga. This was accomplished by combining phenological and genetic data. Every 2 weeks over a period of 2 years, we measured flowering and fruiting phenology to evaluate the activity and intensity of phenophases (n = 60). We evaluated the mating system, pollen ovule ratio and genotypes from progeny and mother plants using 8 nuclear microsatellite loci. We observed flowering and fruiting of V. curassavica at low intensity throughout the entire year, but with 2 distinct peaks, one of which was seasonal, corresponding to the period of gradual increase of temperature and photoperiod. Overlapping of flowering and fruiting strategies favors gene flow among different groups of individuals and between populations by attraction of fauna throughout the year. Analysis of the mating system indicates that V. curassavica is a typical outcrossed species (t^ = 0.98; pollen/ovule ratio = 7087.50). Combining phenology with genetic studies improved our understanding of the reproductive strategies of this species. The typical outcrossing system of V. curassavica reflects the existence of functional self-incompatibility mechanisms still unaffected by changes in genetic balance by polyploidy. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Host reproductive phenology drives seasonal patterns of host use in mosquitoes.

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Nathan D Burkett-Cadena

2011-03-01

Full Text Available Seasonal shifts in host use by mosquitoes from birds to mammals drive the timing and intensity of annual epidemics of mosquito-borne viruses, such as West Nile virus, in North America. The biological mechanism underlying these shifts has been a matter of debate, with hypotheses falling into two camps: (1 the shift is driven by changes in host abundance, or (2 the shift is driven by seasonal changes in the foraging behavior of mosquitoes. Here we explored the idea that seasonal changes in host use by mosquitoes are driven by temporal patterns of host reproduction. We investigated the relationship between seasonal patterns of host use by mosquitoes and host reproductive phenology by examining a seven-year dataset of blood meal identifications from a site in Tuskegee National Forest, Alabama USA and data on reproduction from the most commonly utilized endothermic (white-tailed deer, great blue heron, yellow-crowned night heron and ectothermic (frogs hosts. Our analysis revealed that feeding on each host peaked during periods of reproductive activity. Specifically, mosquitoes utilized herons in the spring and early summer, during periods of peak nest occupancy, whereas deer were fed upon most during the late summer and fall, the period corresponding to the peak in births for deer. For frogs, however, feeding on early- and late-season breeders paralleled peaks in male vocalization. We demonstrate for the first time that seasonal patterns of host use by mosquitoes track the reproductive phenology of the hosts. Peaks in relative mosquito feeding on each host during reproductive phases are likely the result of increased tolerance and decreased vigilance to attacking mosquitoes by nestlings and brooding adults (avian hosts, quiescent young (avian and mammalian hosts, and mate-seeking males (frogs.

Age-related changes in somatic condition and reproduction in the Eurasian beaver: Resource history influences onset of reproductive senescence.

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Ruairidh D Campbell

Full Text Available Using 15 years of data from a stable population of wild Eurasian beavers (Castor fiber, we examine how annual and lifetime access to food resources affect individual age-related changes in reproduction and somatic condition. We found an age-related decline in annual maternal reproductive output, after a peak at age 5-6. Rainfall, an established negative proxy of annual resource availability for beavers, was consistently associated with lower reproductive output for females of all ages. In contrast, breeding territory quality, as a measure of local resource history over reproductive lifetimes, caused differences in individual patterns of reproductive senescence; animals from lower quality territories senesced when younger. Litter size was unrelated to maternal age, although adult body weight increased with age. In terms of resource effects, in poorer years but not in better years, older mothers produced larger offspring than did younger mothers, giving support to the constraint theory. Overall, our findings exemplify state-dependent life-history strategies, supporting an effect of resources on reproductive senescence, where cumulative differences in resource access, and not just reproductive strategy, mediate long-term reproductive trade-offs, consistent with the disposable soma and reproductive restraint theories. We propose that flexible life-history schedules could play a role in the dynamics of populations exhibiting reproductive skew, with earlier breeding opportunities leading to an earlier senescence schedule through resource dependent mechanisms.

Phylogeography in Response to Reproductive Strategies and Ecogeographic Isolation in Ant Species on Madagascar: Genus Mystrium (Formicidae: Amblyoponinae).

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Graham, Natalie R; Fisher, Brian L; Girman, Derek J

2016-01-01

The bulk of models used to understand the species diversification on Madagascar have been constructed using vertebrate taxa. It is not clear how these models affect less vagile species that may interact at a variety of spatial scales. Several studies on vertebrates have divided Madagascar into east-west bioclimatic regions, suggesting there is a fundamental division between eastern wet-adapted and western dry-adapted taxa. An alternative model of ecogeographic constraints shows a north-south division. We test whether the diversification in a small arthropod with variable degrees of dispersal conform to either model of ecogeographic constraints proposed for vertebrate taxa. We employ a molecular taxonomic dataset using ~2 kilobases nuDNA (Wg, LW Rh, Abd-A, 28s) and 790 basepairs mtDNA (CO1), along with geographic and habitat data, to examine the diversification patterns of the ant genus Mystrium Roger, 1862, (Subfamily Amblyoponinae) from Madagascar. The nuclear and mitochondrial phylogenies were both congruent with morphospecies as indicated in a recent revision of the genus. Species of Mystrium practice different colony reproductive strategies (winged queens vs non-winged queens). Alternate reproductive strategies led to inequalities in female dispersal ability among species, providing an additional layer for examination of the impacts of vagility on divergence, especially when measured using a maternally inherited locus. Mystrium species distribution patterns support these models of ecogeographic constraints. Reproductive strategy effected how Mystrium mtDNA lineages were associated with large-scale habitat distinctions and various topographical features. Furthermore, in some cases we find microgeographic population structure which appears to have been impacted by localized habitat differences (tsingy limestone formations, littoral forest) on a scale much smaller than that found in vertebrates. The current system offers a finer scale look at species

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

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

2015-01-01

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

The opportunistic feeding and reproduction strategies of the annual fish Cynopoecilus melanotaenia (Cyprinodontiformes: Rivulidae inhabiting ephemeral habitats on southern Brazil

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Cristina da Silva Gonçalves

Full Text Available Most Rivulidae fishes are popularly known as annual fishes which live in ephemeral environments such as pools, that obligatorily dry out seasonally causing the death of adult individuals. They have unique biological characteristics such as small body size, early sexual maturation, continuous reproduction, an elaborated courtship behavior, and a great reproductive capacity among fishes. The rivulids are widely distributed in North, Central and South America. In this study, the diet and reproductive biology of Cynopoecilus melanotaenia was analyzed. A total of 263 specimens were collected and the analysis of 233 gastrointestinal contents revealed an invertivorous diet composed mainly of small crustaceans (Cladocera, Amphipoda, and Ostracoda and immature insects (Chaoboridae, Culicidae, Syrphidae, but mainly Chironomidae larvae. Lepidophagy on male's diet was also registered. Fecundity was estimated by analyzing 59 pairs of mature ovaries and ranged from 2 to 157 oocytes (mean, 19 ± 26[SD]. The species has fractional spawning, a strategy to increase the chance of survival to prolonged depletions. This study is the first to investigate the reproductive biology of C. melanotaenia. The results confirmed the opportunistic character of the rivulid C. melanotaenia and provided unreported reproductive information that may aid conservation of the species.

Innovative non-animal testing strategies for reproductive toxicology: the contribution of Italian partners within the EU project ReProTect

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Stefano Lorenzetti

2011-12-01

Full Text Available Reproductive toxicity, with its many targets and mechanisms, is a complex area of toxicology; thus, the screening and identification of reproductive toxicants is a main scientific challenge for the safety assessment of chemicals, including the European Regulation on Chemicals (REACH. Regulatory agencies recommend the implementation of the 3Rs principle (refinement, reduction, replacement as well as of intelligent testing strategies, through the development of in vitro methods and the use of mechanistic information in the hazard identification and characterization steps of the risk assessment process. The EU Integrated Project ReProTect (6th Framework Programme implemented an array of in vitro tests to study different building blocks of the mammalian reproductive cycle: methodological developments and results on male and female germ cells, prostate and placenta are presented.

Long-term consequences of disturbances on reproductive strategies of the rare epiphytic lichen Lobaria pulmonaria: clonality a gift and a curse.

Science.gov (United States)

Singh, Garima; Dal Grande, Francesco; Werth, Silke; Scheidegger, Christoph

2015-01-01

The effect of disturbance on symbiotic organisms such as lichens is particularly severe. In case of heterothallic lichen-forming fungi, disturbances may lead to unbalanced gene frequency and patchy distribution of mating types, thus inhibiting sexual reproduction and imposing clonality. The impact of disturbance on reproductive strategies and genetic diversity of clonal systems has so far received little attention. To infer the effects of disturbances on mating-type allele frequencies and population structure, we selected three populations in the Parc Jurassien Vaudois (Switzerland), which were affected by uneven-aged forestry, intensive logging and fire, respectively. We used microsatellite markers to infer genetic diversity, allelic richness and clonal diversity of the epiphytic lichen Lobaria pulmonaria and used L. pulmonaria-specific MAT1-1 and MAT1-2 markers to analyse the frequency and distribution of mating types of 889 individuals. Our study shows that stand-replacing disturbances affect the mating-type frequency and distribution, thus compromising the potential for sexual reproduction. The fire-disturbed area had a significantly lower genetic and genotypic diversity and a higher clonality. Furthermore, the majority of compatible mating pairs in this area were beyond the effective vegetative dispersal range of the species. We conclude that stand-replacing disturbances lead to lower chances of sex and symbiont reshuffling and thus have long-lasting negative consequences on the reproductive strategies and adaptive potential of epiphytic lichen symbioses. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

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Ashlee N Smith

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

Herbivore-mediated ecological costs of reproduction shape the life history of an iteroparous plant.

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Miller, Tom E X; Tenhumberg, Brigitte; Louda, Svata M

2008-02-01

Plant reproduction yields immediate fitness benefits but can be costly in terms of survival, growth, and future fecundity. Life-history theory posits that reproductive strategies are shaped by trade-offs between current and future fitness that result from these direct costs of reproduction. Plant reproduction may also incur indirect ecological costs if it increases susceptibility to herbivores. Yet ecological costs of reproduction have received little empirical attention and remain poorly integrated into life-history theory. Here, we provide evidence for herbivore-mediated ecological costs of reproduction, and we develop theory to examine how these costs influence plant life-history strategies. Field experiments with an iteroparous cactus (Opuntia imbricata) indicated that greater reproductive effort (proportion of meristems allocated to reproduction) led to greater attack by a cactus-feeding insect (Narnia pallidicornis) and that damage by this herbivore reduced reproductive success. A dynamic programming model predicted strongly divergent optimal reproductive strategies when ecological costs were included, compared with when these costs were ignored. Meristem allocation by cacti in the field matched the optimal strategy expected under ecological costs of reproduction. The results indicate that plant reproductive allocation can strongly influence the intensity of interactions with herbivores and that associated ecological costs can play an important selective role in the evolution of plant life histories.

Increase in male reproductive success and female reproductive investment in invasive populations of the harlequin ladybird Harmonia axyridis.

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Guillaume J M Laugier

Full Text Available Reproductive strategy affects population dynamics and genetic parameters that can, in turn, affect evolutionary processes during the course of biological invasion. Life-history traits associated with reproductive strategy are therefore potentially good candidates for rapid evolutionary shifts during invasions. In a series of mating trials, we examined mixed groups of four males from invasive and native populations of the harlequin ladybird Harmonia axyridis mating freely during 48 hours with one female of either type. We recorded the identity of the first male to copulate and after the 48 h-period, we examined female fecundity and share of paternity, using molecular markers. We found that invasive populations have a different profile of male and female reproductive output. Males from invasive populations are more likely to mate first and gain a higher proportion of offspring with both invasive and native females. Females from invasive populations reproduce sooner, lay more eggs, and have offspring sired by a larger number of fathers than females from native populations. We found no evidence of direct inbreeding avoidance behaviour in both invasive and native females. This study highlights the importance of investigating evolutionary changes in reproductive strategy and associated traits during biological invasions.

Switch from sexual to parthenogenetic reproduction in a zebra shark.

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Dudgeon, Christine L; Coulton, Laura; Bone, Ren; Ovenden, Jennifer R; Thomas, Severine

2017-01-16

Parthenogenesis is a natural form of asexual reproduction in which embryos develop in the absence of fertilisation. Most commonly found in plants and invertebrate organisms, an increasing number of vertebrate species have recently been reported employing this reproductive strategy. Here we use DNA genotyping to report the first demonstration of an intra-individual switch from sexual to parthenogenetic reproduction in a shark species, the zebra shark Stegostoma fasciatum. A co-housed, sexually produced daughter zebra shark also commenced parthenogenetic reproduction at the onset of maturity without any prior mating. The demonstration of parthenogenesis in these two conspecific individuals with different sexual histories provides further support that elasmobranch fishes may flexibly adapt their reproductive strategy to environmental circumstances.

Veterinary management of snake reproduction.

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Stahl, Scott J

2002-09-01

The reptile veterinarian should approach the breeder with a comprehensive plan involving a review of proper husbandry, nutrition, record keeping, and a thorough prebreeding evaluation of the snakes. In addition, an evaluation of the reproductive strategy, assistance with confirming and monitoring gestation, and a review of potential reproductive complications will help to prepare the snake owner for a successful breeding season.

Central dose data management and analysis in IT-driven radiation protection strategies

International Nuclear Information System (INIS)

Ward, M.; Hughes, D.; Connolly, P.; Moores, B. M.

2005-01-01

The applications of information technology in health care are now widespread and continue to grow. Medical imaging is at the forefront of this revolution and the introduction of digital detection methods to replace film is now addressing the diagnostic X-ray market, the most routinely employed imaging modality. The introduction of picture archiving and communication systems, hospital and radiology information systems is well underway, and the integration of radiation protection initiatives into these developments is desirable. In north-west UK, a project aimed at developing and implementing IT-driven radiation protection strategies has been underway for the past 10 y. Such strategies are geared towards the support of European Commission patient dose directive 97/43 EURATOM, in particular the need to implement clinical audit, patient dose audit and to establish dose reference levels. This paper demonstrates the national and local requirements for establishing a central dose data management system for use in radiation protection strategies. In particular, such a system can help develop and support the role of a medical physics expert in optimisation. The scientific requirements for such an approach are presented in this paper, and a prototype system is described. Preliminary results obtained with the central data management facility are also presented and the implication for analysing multiple site dose data in optimisation strategies for digital radiographic technology is highlighted. (authors)

DEP and AFO regulate reproductive habit in rice.

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Kejian Wang

2010-01-01

Full Text Available Sexual reproduction is essential for the life cycle of most angiosperms. However, pseudovivipary is an important reproductive strategy in some grasses. In this mode of reproduction, asexual propagules are produced in place of sexual reproductive structures. However, the molecular mechanism of pseudovivipary still remains a mystery. In this work, we found three naturally occurring mutants in rice, namely, phoenix (pho, degenerative palea (dep, and abnormal floral organs (afo. Genetic analysis of them indicated that the stable pseudovivipary mutant pho was a double mutant containing both a Mendelian mutation in DEP and a non-Mendelian mutation in AFO. Further map-based cloning and microarray analysis revealed that dep mutant was caused by a genetic alteration in OsMADS15 while afo was caused by an epigenetic mutation in OsMADS1. Thus, OsMADS1 and OsMADS15 are both required to ensure sexual reproduction in rice and mutations of them lead to the switch of reproductive habit from sexual to asexual in rice. For the first time, our results reveal two regulators for sexual and asexual reproduction modes in flowering plants. In addition, our findings also make it possible to manipulate the reproductive strategy of plants, at least in rice.

Traditional Chinese Medicine in the Treatment of Reproductive Disorders of Large Animals in Asia

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ZH Zuo, TY Zhang, J Chu, Q Zhang, YX Guo, ZQ Shen and C He

2016-11-01

Full Text Available Reproductive diseases have been a great threat in large animal herds. Before induction of western medicines, traditional Chinese medicine (TCM that is based on the use of herbal medicine, acupuncture, massage and other forms of therapy has been practiced in China for thousands of years. The foundational text of Chinese medicine dated back to 5th century to 3rd century BCE, humans in China began developing the TCM therapy by maintaining normal homeostasis and body functions. Traditional Chinese medicine prophylaxis is a very different strategy from that of the western medicine, targeting the balance of the diseased animals as compared to the single lesion. Traditional Chinese medicine was also applied to cure ruminant’s reproductive disorders such as infertility, abortion and retained placenta. With the increasing concerns of the antibiotic resistance and drug abuse happened, TCM has acquired re-recognition as compared to western medicines due to eco-friendly consumer-driven developments and less residue in food chains. More importantly, a growing number of active substances or extracts with the reliable efficacy are being identified, meanwhile, the quality control measures are satisfied in the large-scale production already. However, few TCM is recognized to be used internationally as the popular human medication. Even less TCM is prescribed legally to animal industry due to poor understanding TCM philosophy and lack of the right guidelines of the registration. This summary aims to elucidate the TCM application in the treatment of the reproductive disorder in large animals and offer alternative strategies for prophylaxis.

Unisexual reproduction in Huntiella moniliformis.

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Wilson, A M; Godlonton, T; van der Nest, M A; Wilken, P M; Wingfield, M J; Wingfield, B D

2015-07-01

Sexual reproduction in fungi is controlled by genes present at the mating type (MAT) locus, which typically harbors transcription factors that influence the expression of many sex-related genes. The MAT locus exists as two alternative idiomorphs in ascomycetous fungi and sexual reproduction is initiated when genes from both idiomorphs are expressed. Thus, the gene content of this locus determines whether a fungus is heterothallic (self-sterile) or homothallic (self-fertile). Recently, a unique sub-class of homothallism has been described in fungi, where individuals possessing a single MAT idiomorph can reproduce sexually in the absence of a partner. Using various mycological, molecular and bioinformatic techniques, we investigated the sexual strategies and characterized the MAT loci in two tree wound-infecting fungi, Huntiella moniliformis and Huntiella omanensis. H. omanensis was shown to exhibit a typically heterothallic sexual reproductive cycle, with isolates possessing either the MAT1-1 or MAT1-2 idiomorph. This was in contrast to the homothallism via unisexual reproduction that was shown in H. moniliformis, where only the MAT1-2-1 gene was present in sexually reproducing cultures. While the evolutionary benefit and mechanisms underpinning a unisexual mating strategy remain unknown, it could have evolved to minimize the costs, while retaining the benefits, of normal sexual reproduction. Copyright © 2015 Elsevier Inc. All rights reserved.

Gender perspectives of sexual and reproductive practices of people ...

African Journals Online (AJOL)

Gender perspectives of sexual and reproductive practices of people living with ... the spread of HIV infection has become the role of gender inequality.1, 2 The ... mainly driven by the subordinate traditional gender roles of women in this culture.

Simulation modelling of central order processing system under resource sharing strategy in demand-driven garment supply chains

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Ma, K.; Thomassey, S.; Zeng, X.

2017-10-01

In this paper we proposed a central order processing system under resource sharing strategy for demand-driven garment supply chains to increase supply chain performances. We examined this system by using simulation technology. Simulation results showed that significant improvement in various performance indicators was obtained in new collaborative model with proposed system.

Life strategies of semi-desert plants: mechanisms of dispersal and reproduction in the thermomediterranean shrubland community Anabasio-Euzomodendretum bourgaeani

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Hensen, Isabell

1999-06-01

Full Text Available The present study describes mechanisms of dispersal and reproduction in the thermomediterranean shrubland community Anabasio hispanicae-Euzomodendretum bourgaeani. The life strategy analysis based on sociological releves was carried out in Tabernas Desert (Province Almería. The biological significance of the occurring life strategies is represented by the mean group quantity fraction (GM. The dominant life strategy subdivisión of Anabasio-Euzomodendretum bourgaeani is that of Perennial stayers with short-range dispersal, with sexual reproduction. Reproduction takes place mainly by seeds; clonal reproduction does not appear to have any significance for the colonization of this semi-desert habitat. The community is characterized by a low dispersal capacity, achieved by several mechanisms for avoiding dispersal. A high percentage of the species that mature and fructify shortly before or during the hot and rainless summer, stores at least a subset of seeds in an aerial diaspore bank to assure that dispersal and germination coincide with an advantageous soil water supply. Additionally, immediate seed germination is frequently inhibited by high temperature.El presente trabajo describe los mecanismos de dispersión y reproducción en la comunidad de matorral termomediterráneo Anabasio hispanicae-Euzomodendretum bourgaeani. El análisis de las estrategias de vida se basa en inventarios fitosociológicos realizados en el desierto de Tabernas (provincia de Almería. La importancia biológica de las estrategias de vida es expresada por el cociente medio de la cantidad del grupo (GM. La estrategia de vida predominante es el subgrupo de los perennes con dispersión a corta distancia, con reproducción sexual. Las especies se reproducen principalmente por semillas y la reproducción clonal no parece tener importancia para la colonización del habitat semidesértico. La comunidad está caracterizada por una baja capacidad de dispersión que se consigue por

Stereology as a tool to assess reproduction strategy and fecundity of teleost fishes

DEFF Research Database (Denmark)

Bucholtz, Rikke Hagstrøm

methods to assess fecundity and reproductive strategies. The strength of the stereological method being that, in combination with conventional histological analysis, quantification of all oocyte categories is possible, as well as registration of qualitative characteristics relating to spawning history...... of oocyte dynamics in fish and were successfully implemented in herring ovaries for quantification of both oocyte numbers and sizes as well as total volume fraction of atretic oocytes, introducing a negligible error to the total variance of estimates. The histological nature of the stereological methods...... facilitated a ready validation of maturity data, distinguishing first time spawners from repeat spawners, as well as a ready recognition of ongoing oocyte recruitment in early maturity stages, early stage atresia, POFs and residual eggs. Analyzing a sample of females all collected during a short time frame...

Appraisal of the adequacy of the application of customer-driven marketing strategies to the Nigeria National Housing Fund scheme

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Chuka Uzoma Ifediora

2015-07-01

Full Text Available This study appraised the adequacy of the application of customer-driven marketing strategies to the Nigeria National Housing Fund (NHF scheme. The study objective was to assess the adequacy of the application of market segmentation, targeting, differentiation and positioning by the NHF implementers. The study adopted descriptive and exploratory research designs. Various offices of the Federal Mortgage Bank of Nigeria (the implementers of the NHF scheme in Abuja, Lagos, PortHarcourt, Ibadan and Enugu, as well as the 19 state/ district offices in these zones were studied. The study population comprised 201 management staff and officers in these offices. A census was carried out, considering the size of the population and the nature of the investigation. Structured questionnaire was used to collect data for this study. Analysis of variance (ANOVA was used to test the formulated hypothesis at 5% level of significance. The hypothesis test revealed that the application of market segmentation, targeting, differentiation and positioning by the NHF implementers is not adequate (Fcal = 95.239, p = 0.000 < 0.05. Following the finding, it is concluded that there is a low level of application of customer-driven marketing strategies in the National Housing Fund (NHF implementation. In line with the finding and conclusion of this study, it is recommended that the adoption and application of the customer-driven marketing strategies model for housing development programmes will aid the successful implementation of housing development programmes, thus leading to a substantial reduction in housing deficit level.

Effects of Teachers' Epistemological, Health View and Pedagogical Beliefs on the Didactic Strategy to Teach Adolescent Reproductive Health: A Cameroonian Perspective

Science.gov (United States)

Nchia, Lawrence Ntam; Joseph, Tamesse L.; Fonkeng, George Epah; Ngeh, George Nditafon

2017-01-01

Despite the recommended didactic strategy to teach Adolescent Reproductive Health in Cameroon using Competency Based Approach with entry through problem situations, a lot of resistance is till observed within biology teachers in this multicultural and linguistic country. This cross sectional study uses Structural Equation Modelling (SEM)…

Chance, choice, and the future of reproduction.

Science.gov (United States)

Miller, W B

1983-11-01

The evolution of reproduction has been characterized by the development of complex biological and behavioral mechanisms that serve to regulate chance events. Human reproduction has been characterized by the increasing importance of individual choice. Some contemporary manifestations of this broad trend are the high incidence of contraceptive and "proceptive" behavior among couples in Western, industrialized nations. The former behavior willingly attempts to prevent conception while the latter actively attempts to induce conception (such as concentrating intercourse around the time of ovulation). Both patterns of behavior indicate that a choice is being made. A 3-year study of 1000 women revealed proceptive behavior as the most important factor predicting occurance of conception among married couples in the United States. The general strategeis people follow while making childbearing decisions: termination, sequencing, and pre-planning form a continuum following the historical trend toward greater reproductive control. In the terminating strategy, a couple makes no decision about child bearing until the number of children they have become enough or too much. In the sequencing strategy, decisions to have children are made 1 child at a time until a satisfactory limit is reached. In the pre-planning strategy, a plan is worked out ahead of time and is subsequently carried out. As new reproductive technology is introduced and as progressive change is made in society's reproductive related values and beliefs, choice will continue to dominate chance as the highly likely trend for the future of reproduction. Surrogate maternity is just 1 example of this trend. However, these new options, which culminate in the theory and practice of "progensis," (still in its infancy), as well as offering a rich opportunity, can also incur psychological burdens on a couple. Thus, as with any kind of freedom, these developments will require care, caution and responsibility.

Market driven strategy for acquisition of waste acceptance and transportation services for commercial spent fuel in the United States

International Nuclear Information System (INIS)

Lemeshewky, W.; Macaluso, C.; Smith, P.; Teer, B.

1998-05-01

The Department of Energy has the responsibility for the shipment of spent nuclear fuel (SNF) from commercial reactors to a Federal facility for storage and/or disposal. DOE has developed a strategy for a market driven approach for the acquisition of transportation services and equipment which will maximize the participation of private industry. To implement this strategy, DOE is planning to issue a Request for Proposal (RFP) for the provision of the required services and equipment to accept SNF from the utilities and transport the SNF to a Federal facility. The paper discusses this strategy and describes the RFP

Infanticide in tree squirrels - a male reproductive strategy?

African Journals Online (AJOL)

1986-07-25

Jul 25, 1986 ... ... of such behaviour. The interpretation of infant killing as a sexually selected male reproductive ... stones of the sexual selection hypothesis of infanticide. The ... of genetically based strain differences in the occurrence of infanticide in ... Aggression plays a prominent role in social behaviour, with both males.

Reproductive strategies and genetic variability in tropical freshwater fish

Directory of Open Access Journals (Sweden)

Maria Dolores Peres Lassala

2007-01-01

Full Text Available We estimated the genetic variability of nine fish species from the Brazilian upper Paraná River floodplain (Astyanax altiparanae, Hoplias malabaricus, Leporinus lacustris, Loricariichthys platymetopon, Parauchenipterus galeatus, Pimelodus maculatus, Rhaphiodon vulpinus, Roeboides paranensis and Serrasalmus marginatus based on data for 36 putative allozyme loci obtained using corn starch gel electrophoresis of 13 enzymatic systems: aspartate aminotransferase (EC 2.6.1.1, acid phosphatase (EC 3.1.3.2, esterase (EC 3.1.1.1, glycerol-3-phosphate dehydrogenase (EC 1.1.1.8, glucose-6-phosphate dehydrogenase (EC 1.1.1.49, glucose-6-phosphate isomerase (EC 5.3.1.9, Iditol dehydrogenase (EC 1.1.1.14, isocitrate dehydrogenase - NADP+ (EC 1.1.1.42, L-lactate dehydrogenase (EC 1.1.1.27, malate dehydrogenase (EC 1.1.1.37, malate dehydrogenase-NADP+ (EC 1.1.1.40, phosphoglucomutase (EC 5.4.2.2 and superoxide dismutase, (EC 1.15.1.1. The mean expected heterozygosity varied from zero to 0.147. When data from the literature for 75 species of tropical fish were added to the nine species of this study, the heterozygosity values differed significantly among the groups of different reproductive strategies. The highest mean heterozygosity was for the non-migratory without parental care, followed by the long-distance migratory, and the lowest mean was for the non-migratory with parental care or internal fecundation.

Mum, why do you keep on growing? Impacts of environmental variability on optimal growth and reproduction allocation strategies of annual plants.

Science.gov (United States)

De Lara, Michel

2006-05-01

In their 1990 paper Optimal reproductive efforts and the timing of reproduction of annual plants in randomly varying environments, Amir and Cohen considered stochastic environments consisting of i.i.d. sequences in an optimal allocation discrete-time model. We suppose here that the sequence of environmental factors is more generally described by a Markov chain. Moreover, we discuss the connection between the time interval of the discrete-time dynamic model and the ability of the plant to rebuild completely its vegetative body (from reserves). We formulate a stochastic optimization problem covering the so-called linear and logarithmic fitness (corresponding to variation within and between years), which yields optimal strategies. For "linear maximizers'', we analyse how optimal strategies depend upon the environmental variability type: constant, random stationary, random i.i.d., random monotonous. We provide general patterns in terms of targets and thresholds, including both determinate and indeterminate growth. We also provide a partial result on the comparison between ;"linear maximizers'' and "log maximizers''. Numerical simulations are provided, allowing to give a hint at the effect of different mathematical assumptions.

Interaction of environment and reproductive processes in cattle

International Nuclear Information System (INIS)

Thatcher, W.W.; Collier, R.J.; Beede, D.K.; Wilcox, C.J.

1986-01-01

Effects of environment on reproductive processes of female cattle are described. Variation in fertility responses is divided into environmental and genetic effects. Environmental effects are defined as all effects non-genetic, and emphasis is placed on the quantitation of various climatic measurements (e.g. maximum environmental temperature) associated with reproductive performance. Sensitivities of various reproductive events to thermal stress are defined and include such responses as: reproductive behaviour; hormonal balance related to both reproductive events and metabolic adaptations; alterations in uterine blood flow; embryonic death; conceptus development; placental function; and restoration of postpartum reproductive function. Also discussed are several management strategies to improve animal productivity, including environmental modification and the potential for genetic development of less heat-sensitive animals. (author)

Parasitoid Diaeretiella rapae (Hymenoptera: Braconidae) Adjusts Reproductive Strategy When Competing for Hosts.

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Kant, Rashmi; Minor, Maria A

2017-06-01

Parasitoid fitness depends on its ability to manipulate reproductive strategies when in competition. This study investigated the parasitism and sex allocation strategies of the parasitic wasp Diaeretiella rapae McIntosh at a range of host (Brevicoryne brassicae L.) and conspecific densities. The results suggest that D. rapae females adjust their progeny production and progeny sex ratio with changing competition. When foraging alone, female D. rapae parasitize larger number of B. brassicae nymphs when the number of available hosts is increased, but the overall proportion of parasitized hosts decreases with increase in host density. The proportion of female offspring also decreases with elevated host density. Increase in the number of female D. rapae foraging together increased total parasitism, but reduced relative contribution of each individual female. The number of female progeny decreased when multiple females competed for the same host. However, foraging experience in the presence of one or more conspecifics increased the parasitism rate and proportion of female progeny. Competing females were more active during oviposition and had shorter lives. The study suggests that both host and foundress (female parasitoid) densities have significant effect on progeny production, sex allocation, and longevity of foraging females. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Lifetime reproductive success in the solitary endoparasitoid, Venturia canescens

NARCIS (Netherlands)

Harvey, J.A.; Harvey, I.F.; Thompson, D.J.

2001-01-01

Parasitoid wasps have long been considered excellent organisms in studies examining the evolution of reproductive and life- history strategies. In examining the lifetime reproductive success of parasitoids in the laboratory, most investigations have provided the insects with excess hosts and food,

Mammal Reproductive Strategies Driven by Offspring Mortality-Size Relationships

DEFF Research Database (Denmark)

Sibly, Richard M.; Brown, James H.

2009-01-01

Trade-offs have long been a major theme in life-history theory, but they have been hard to document. We introduce a new method that reveals patterns of divergent trade-offs after adjusting for the pervasive variation in rate of resource allocation to offspring as a function of body size and lifes......Trade-offs have long been a major theme in life-history theory, but they have been hard to document. We introduce a new method that reveals patterns of divergent trade-offs after adjusting for the pervasive variation in rate of resource allocation to offspring as a function of body size...

Strategies for engaging the private sector in sexual and reproductive health: how effective are they?

Science.gov (United States)

Peters, David H; Mirchandani, Gita G; Hansen, Peter M

2004-10-01

The private health sector provides a significant portion of sexual and reproductive health (SRH) services in developing countries. Yet little is known about which strategies for intervening with private providers can improve quality or coverage of services. We conducted a systematic review of the literature through PubMed from 1980 to 2003 to assess the effectiveness of private sector strategies for SRH services in developing countries. The strategies examined were regulating, contracting, financing, franchising, social marketing, training and collaborating. Over 700 studies were examined, though most were descriptive papers, with only 71 meeting our inclusion criteria of having a private sector strategy for one or more SRH services and the measurement of an outcome in the provider or the beneficiary. Nearly all studies (96%) had at least one positive association between SRH and the private sector strategy. About three-quarters of the studies involved training private providers, though combinations of strategies tended to give better results. Maternity services were most commonly addressed (55% of studies), followed by prevention and treatment of sexually transmitted diseases (32%). Using study design to rate the strength of evidence, we found that the evidence about effectiveness of private sector strategies on SRH services is weak. Most studies did not use comparison groups, or they relied on cross-sectional designs. Nearly all studies examined short-term effects, largely measuring changes in providers rather than changes in health status or other effects on beneficiaries. Five studies with more robust designs (randomized controlled trials) demonstrated that contraceptive use could be increased through supporting private providers, and showed cases where the knowledge and practices of private providers could be improved through training, regulation and incentives. Although tools to work with the private sector offer considerable promise, without stronger research

Reproduction numbers of infectious disease models

Directory of Open Access Journals (Sweden)

Pauline van den Driessche

2017-08-01

Full Text Available This primer article focuses on the basic reproduction number, ℛ0, for infectious diseases, and other reproduction numbers related to ℛ0 that are useful in guiding control strategies. Beginning with a simple population model, the concept is developed for a threshold value of ℛ0 determining whether or not the disease dies out. The next generation matrix method of calculating ℛ0 in a compartmental model is described and illustrated. To address control strategies, type and target reproduction numbers are defined, as well as sensitivity and elasticity indices. These theoretical ideas are then applied to models that are formulated for West Nile virus in birds (a vector-borne disease, cholera in humans (a disease with two transmission pathways, anthrax in animals (a disease that can be spread by dead carcasses and spores, and Zika in humans (spread by mosquitoes and sexual contacts. Some parameter values from literature data are used to illustrate the results. Finally, references for other ways to calculate ℛ0 are given. These are useful for more complicated models that, for example, take account of variations in environmental fluctuation or stochasticity. Keywords: Basic reproduction number, Disease control, West Nile virus, Cholera, Anthrax, Zika virus

Reproductive cycles of deer.

Science.gov (United States)

Asher, G W

2011-04-01

The cervids are a complex assemblage of taxa showing extreme diversity in morphology, physiology, ecology and geographical distribution. Reproductive strategies adopted by various species are also diverse, and include a range from highly seasonal to completely aseasonal birth patterns. The recent growth in knowledge on cervid reproduction is strongly biased towards the larger-bodied, gregarious mixed grazer-browser species that have adapted well to human management and commercialisation. These species tend to represent 'K-selected' climax species characterised by very productive annual breeding success, singleton births and long breeding life (10+ years). Conversely, we know relatively little about the reproductive patterns of the 'r-selected' smaller-bodied, solitary (and often highly territorial), forest-dwelling browser species, often characterised by great fecundity (twinning) and shorter breeding life (<10 years). This group includes many of the endangered cervid taxa. This review extends earlier reviews to include more recent work on cervid reproductive cycles, particularly in relation to environmental factors influencing gestation length. Copyright © 2010 Elsevier B.V. All rights reserved.

A Survey of Reproductive Management Strategies on US Commercial Dairy Farms

OpenAIRE

Olynk, Nicole J.; Wolf, Christopher A.

2008-01-01

Reproductive performance on the dairy farm affects the dairy’s profit because it directly affects milk production, the availability of replacements, the amounts of voluntary and involuntary culling, breeding costs, and costs associated with veterinary care (Britt, 1985). Reproductive management programs selected for implementation differ across farms due to varying on-farm costs, such as labor costs, opportunity costs of management and labor, as well as facilities, farm goals and values, and ...

Assisted reproductive technologies are an integrated part of national strategies addressing demographic and reproductive challenges

DEFF Research Database (Denmark)

Ziebe, Søren; Devroey, Paul; Jensen, Tina Kold

2012-01-01

The decline in the total fertility rate in the latter half of the 20th century in many European countries is becoming increasingly important in determining the demographic composition of Europe and its individual member states. This review focuses on discussion surrounding how assisted reproductive...

Reproductive activity and welfare of rabbit does

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C. Castellini

2010-04-01

Full Text Available This paper reviews the relationships between reproductive performance and welfare of the rabbit does. In the last 10 years the profitability of rabbit farms has increased mainly due to improvements in management and genetic selection but several problems mainly related to animal welfare have also occurred. The mortality and rates of female replacement per year are very high and the replaced females often show poor body condition and low performance. The effect of kindling order, litter size, genetic strain, weaning age and reproduction rhythm on the reproductive performance and welfare of females and some mechanisms implicated in these effects are discussed. Modern rabbit does produce a lot of milk which have a high energetic value which leads to a mobilization of body fat which results in an energy deficit. In the current reproductive rhythms, there is an extensive overlap between lactation and gestation. The resulting energetic and hormonal antagonism reduces the fertility rate and lifespan of the doe. Strategies to improve the fertility, lifespan and welfare of does are discussed. An approach which combines various strategies seems to be required to meet these objectives. Since the factors involved in this productive system are fixed (genetic strain, environment the most powerful way to improve doe welfare is to choose a reproductive rhythm that is adapted to the physiology of the does.

Life-history strategies of North American elk: trade-offs associated with reproduction and survival

Science.gov (United States)

Sabrina Morano; Kelley M. Stewart; James S. Sedinger; Christopher A. Nicolai; Marty Vavra

2013-01-01

The principle of energy allocation states that individuals should attempt to maximize fitness by allocating resources optimally among growth, maintenance, and reproduction. Such allocation may result in trade-offs between survival and reproduction, or between current and future reproduction. We used a marked population of North American elk (Cervus elaphus...

Reproduction in Leishmania: A focus on genetic exchange.

Science.gov (United States)

Rougeron, V; De Meeûs, T; Bañuls, A-L

2017-06-01

One key process of the life cycle of pathogens is their mode of reproduction. Indeed, this fundamental biological process conditions the multiplication and the transmission of genes and thus the propagation of diseases in the environment. Reproductive strategies of protozoan parasites have been a subject of debate for many years, principally due to the difficulty in making direct observations of sexual reproduction (i.e. genetic recombination). Traditionally, these parasites were considered as characterized by a preeminent clonal structure. Nevertheless, with the development of elaborate culture experiments, population genetics and evolutionary and population genomics, several studies suggested that most of these pathogens were also characterized by constitutive genetic recombination events. In this opinion, we focused on Leishmania parasites, pathogens responsible of leishmaniases, a major public health issue. We first discuss the evolutionary advantages of a mixed mating reproductive strategy, then we review the evidence of genetic exchange, and finally we detail available tools to detect naturally occurring genetic recombination in Leishmania parasites and more generally in protozoan parasites. Copyright © 2016. Published by Elsevier B.V.

Reducing multiple births in assisted reproduction technology.

Science.gov (United States)

Bhattacharya, Siladitya; Kamath, Mohan S

2014-02-01

Multiple pregnancy, a complication of assisted reproduction technology, is associated with poorer maternal and perinatal outcomes. The primary reason behind this is the strategy of replacing more than one embryo during an assisted reproduction technology cycle to maximise pregnancy rates. The solution to this problem is to reduce the number of embryos transferred during in-vitro fertilisation. The transition from triple- to double-embryo transfer, which decreased the risk of triplets without compromising pregnancy rates, was easily implemented. The adoption of a single embryo transfer policy has been slow because of concerns about impaired pregnancy rates in a fresh assisted reproduction technology cycle. Widespread availability of effective cryopreservation programmes means that elective single embryo transfer, along with subsequent frozen embryo transfers, could provide a way forward. Any such strategy will need to consider couples' preferences and existing funding policies, both of which have a profound influence on decision making around embryo transfer. Copyright © 2013 Elsevier Ltd. All rights reserved.

Reproduction in crabs: strategies, invasiveness and environmental influences thereon

NARCIS (Netherlands)

Brink, van den A.M.

2013-01-01

This thesis provides insights into the interconnectedness of crab reproductive biology, the selective forces leading to their development, the possible links to invasiveness and the influences of environmental factors thereon. The empirical data collected and presented in this thesis can be used

Plant and Animal Reproductive Strategies: Lessons from Offspring Size and Number Tradeoffs

Directory of Open Access Journals (Sweden)

K. G. Srikanta Dani

2017-05-01

Full Text Available The tradeoff between offspring size and number is ubiquitous and manifestly similar in plants and animals despite fundamental differences between the evolutionary histories of these two major life forms. Fecundity (offspring number primarily affects parental fitness, while offspring size underpins the fitness of parents and offspring. We provide an overview of theoretical models dealing with offspring size and fitness relationships. We follow that with a detailed examination of life-history constraints and environmental effects on offspring size and number, separately in plants and animals. The emphasis is on seed plants, but we endeavor to also summarize information from distinct animal groups—insects, fishes, reptiles, birds, and mammals. Furthermore, we analyse genetic controls on offspring size and number in two model organisms—Arabidopsis and Drosophila. Despite the deep evolutionary divergence between plants and animals, we find four trends in reproductive strategy that are common to both lineages: (i offspring size is generally less variable than offspring number, (ii offspring size increases with increasing parent body size, (iii maternal genes restrict offspring size and increase offspring numbers, while zygotic genes act to increase offspring size; such parent-offspring conflicts are enhanced when there is sibling rivalry, and (iv variation in offspring size increases under sub-optimal (harsh environmental conditions. The most salient difference between plants and animals is that the latter tend to produce larger (fewer offspring under sub-optimal conditions while seed plants invest in smaller (many seeds, suggesting that maternal genetic control over offspring size increases in plants but decreases in animals with parental care. The time is ripe for greater experimental exploration of genetic controls on reproductive allocation and parent-offspring conflicts in plants and animals under sub-optimal (harsh environments.

Towards a better understanding of the respective effects of milk yield and body condition dynamics on reproduction in Holstein dairy cows.

Science.gov (United States)

Cutullic, E; Delaby, L; Gallard, Y; Disenhaus, C

2012-03-01

The overall reproductive performance has decreased over the last decades, involving changes in cyclicity, oestrous behaviour and fertility. High milk yield (MY), low body condition score (BCS) and large body condition (BC) loss have been identified as risk factors. However, these effects are often confounded, as high MY and body lipid reserve mobilization are correlated. The aim of this study was to evaluate the respective effects of MY and BC on post-partum ovarian cyclicity, oestrus and fertility of Holstein cows. This study provides novel information, as MY and BC change were uncoupled in the overall dataset that included 98 lactations and milk progesterone profiles. Cows were assigned to two feeding-level groups: high feed, which achieved high MY and moderate BC loss throughout lactation (8410 kg, -1.17 unit from calving to nadir BCS), and low feed, which limited MY and triggered a large BC loss (5719 kg, -1.54 unit). MY and BC had different effects at different stages of the reproductive process. Cyclicity as well as non-fertilization and early embryo mortality were mainly driven by body lipid reserves, whereas oestrous behaviour and late embryo mortality were related to MY. The results point to possible uncoupling between cyclicity, oestrus and early and late embryo survival allowing compensation along the reproductive process and leading to similar final reproductive performance. In compact calving systems, which require high pregnancy rates within a short period, higher MY strategies appear unsuitable even where BCS is maintained, owing to depressed oestrous behaviour and probably increased late embryo mortality, which delays rebreeding. Similarly, strategies that compromise cyclicity and fertility by excessively low BCS are unsuitable.

Therapeutic strategies involving uterine stem cells in reproductive medicine.

Science.gov (United States)

Simoni, Michael; Taylor, Hugh S

2018-04-12

The current review provides an update on recent advances in stem cell biology relevant to female reproduction. Stem cells are undifferentiated cells that often serve as a reservoir of cells to regenerate tissue in settings or injury or cell loss. The endometrium has progenitor stem cells that can replace all of the endometrium during each menstrual cycle. In addition, multipotent endometrial cells replace these progenitor cells when depleted. Recruitment of stem cells from outside of the uterus occurs in setting of increased demand such as ischemia or injury. Bone marrow-derived multipotent stem cells are recruited to the uterus by estrogen or injury-induced expression of the chemokine CXCL12. In the setting of overwhelming injury, especially in the setting of low estrogen levels, there may be insufficient stem cell recruitment to adequately repair the uterus resulting in conditions such as Asherman syndrome or other endometrial defects. In contrast, excessive recruitment of stem cells underlies endometriosis. Enhanced understanding of stem-cell mobilization, recruitment, and engraftment has created the possibility of improved therapy for endometrial defects and endometriosis through enhanced manipulation of stem-cell trafficking. Further, the normal endometrium is a rich source of multipotent stem cells that can be used for numerous applications in regenerative medicine beyond reproduction. A better understanding of reproductive stem-cell biology may allow improved treatment of endometrial disease such as Asherman syndrome and other endometrial receptivity defects. Inhibiting stem-cell mobilization may also be helpful in endometriosis therapy. Finally, endometrial derived multipotent stem cells may play a crucial role in cell therapy for regenerative medicine.

Dinosaur Reproduction and Parenting

Science.gov (United States)

Horner, John R.

Non-avian dinosaur reproductive and parenting behaviors were mostly similar to those of extant archosaurs. Non-avian dinosaurs were probably sexually dimorphic and some may have engaged in hierarchical rituals. Non-avian coelurosaurs (e.g. Troodontidae, Oviraptorosauria) had two active oviducts, each of which produced single eggs on a daily or greater time scale. The eggs of non-coelurosaurian dinosaurs (e.g. Ornithischia, Sauropoda) were incubated in soils, whereas the eggs of non-avian coelurosaurs (e.g. Troodon, Oviraptor) were incubated with a combination of soil and direct parental contact. Parental attention to the young was variable, ranging from protection from predators to possible parental feeding of nest-bound hatchlings. Semi-altricial hadrosaur hatchlings exited their respective nests near the time of their first linear doubling. Some reproductive behaviors, once thought exclusive to Aves, arose first in non-avian dinosaurs. The success of the Dinosauria may be related to reproductive strategies.

Population density shapes patterns of survival and reproduction in Eleutheria dichotoma (Hydrozoa: Anthoathecata).

Science.gov (United States)

Dańko, Aleksandra; Schaible, Ralf; Pijanowska, Joanna; Dańko, Maciej J

2018-01-01

Budding hydromedusae have high reproductive rates due to asexual reproduction and can occur in high population densities along the coasts, specifically in tidal pools. In laboratory experiments, we investigated the effects of population density on the survival and reproductive strategies of a single clone of Eleutheria dichotoma . We found that sexual reproduction occurs with the highest rate at medium population densities. Increased sexual reproduction was associated with lower budding (asexual reproduction) and survival probability. Sexual reproduction results in the production of motile larvae that can, in contrast to medusae, seek to escape unfavorable conditions by actively looking for better environments. The successful settlement of a larva results in starting the polyp stage, which is probably more resistant to environmental conditions. This is the first study that has examined the life-history strategies of the budding hydromedusa E. dichotoma by conducting a long-term experiment with a relatively large sample size that allowed for the examination of age-specific mortality and reproductive rates. We found that most sexual and asexual reproduction occurred at the beginning of life following a very rapid process of maturation. The parametric models fitted to the mortality data showed that population density was associated with an increase in the rate of aging, an increase in the level of late-life mortality plateau, and a decrease in the hidden heterogeneity in individual mortality rates. The effects of population density on life-history traits are discussed in the context of resource allocation and the r/K-strategies' continuum concept.

Diverse modes of reproduction in the marine free-living ciliate Glauconema trihymene

Directory of Open Access Journals (Sweden)

Zufall Rebecca A

2010-04-01

Full Text Available Abstract Background Most free-living ciliates reproduce by equal fission or budding during vegetative growth. In certain ciliates, reproduction occurs inside the cyst wall, viz. reproductive cysts, but more complex reproductive strategies have generally been thought to be confined to parasitic or symbiotic species, e.g. Radiophrya spp. Results In addition to equal fission, asymmetric binary division and reproductive cysts were discovered in the free-living bacterivorous scuticociliate Glauconema trihymene Thompson, 1966. Asymmetric division is an innate physiological state that can be induced by sufficient food, and the higher the food concentration, the longer the asymmetric division persists. During asymmetric division, nuclear and somatic structures divide with transiently arrested cytokinesis and variable positioning of macronuclei. Phylogenetic analysis, based on the small subunit of ribosomal DNA (SSU rDNA sequences, showed that the G. trihymene isolate studied here nests with typical scuticociliates and is paraphyletic to both the symbiotic apostome and astome ciliates, some of which also produce progeny by asymmetric division. Conclusions The asymmetric division in G. trihymene has no precedent among undisturbed free-living ciliates. The coexistence of multiple modes of reproduction may represent a previously undescribed reproductive strategy for ciliates living on food patches in coastal waters. This may also be indicative of similar reproductive strategies among other polyphenic ciliates, which have not been intensively studied. Asymmetric division provides a special opportunity for studying ciliates' phenotypic plasticity and may also illuminate the origins of multicellularity.

Life span and reproductive cost explain interspecific variation in the optimal onset of reproduction.

Science.gov (United States)

Mourocq, Emeline; Bize, Pierre; Bouwhuis, Sandra; Bradley, Russell; Charmantier, Anne; de la Cruz, Carlos; Drobniak, Szymon M; Espie, Richard H M; Herényi, Márton; Hötker, Hermann; Krüger, Oliver; Marzluff, John; Møller, Anders P; Nakagawa, Shinichi; Phillips, Richard A; Radford, Andrew N; Roulin, Alexandre; Török, János; Valencia, Juliana; van de Pol, Martijn; Warkentin, Ian G; Winney, Isabel S; Wood, Andrew G; Griesser, Michael

2016-02-01

Fitness can be profoundly influenced by the age at first reproduction (AFR), but to date the AFR-fitness relationship only has been investigated intraspecifically. Here, we investigated the relationship between AFR and average lifetime reproductive success (LRS) across 34 bird species. We assessed differences in the deviation of the Optimal AFR (i.e., the species-specific AFR associated with the highest LRS) from the age at sexual maturity, considering potential effects of life history as well as social and ecological factors. Most individuals adopted the species-specific Optimal AFR and both the mean and Optimal AFR of species correlated positively with life span. Interspecific deviations of the Optimal AFR were associated with indices reflecting a change in LRS or survival as a function of AFR: a delayed AFR was beneficial in species where early AFR was associated with a decrease in subsequent survival or reproductive output. Overall, our results suggest that a delayed onset of reproduction beyond maturity is an optimal strategy explained by a long life span and costs of early reproduction. By providing the first empirical confirmations of key predictions of life-history theory across species, this study contributes to a better understanding of life-history evolution. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

On Reproductive Work in Spain: Transnational Adoption, Egg Donation, Surrogacy.

Science.gov (United States)

Marre, Diana; San Román, Beatriz; Guerra, Diana

2018-01-01

Spain's plummeting fertility since the late twentieth century may seem to reflect a waning desire for children. Nevertheless, reproductive disappointments resulting from gender inequalities cause many Spanish women to postpone motherhood and experience age-related fertility problems. For them, creating a family often becomes possible only through the reproductive labor of other women. Our analysis of transnational adoption, egg donation, and surrogacy in Spain shows how anonymity and altruism play out in these three strategies, with implications for the valuation of women's reproductive work and relationships among reproductive providers, intermediaries, recipients, and the resulting children.

The cook, the thief, his wife and her lover: on the evolution of the human reproductive strategy.

Science.gov (United States)

Schuiling, G A

2003-12-01

Human reproductive strategy differs from that of most other mammals, including Apes such as the closely related chimpanzee (Pan troglodytes) and the bonobo (Pan paniscus). For example, humans, although basically polygamic, exhibit a strong tendency to (serial) monogamy and--very rare for a mammal--provide biparental care. Moreover, humans are (almost) permanently willing to mate but, in contrast to other species, do so only in private. Unlike chimpanzees and bonobos, the human female exhibits no external signs of ovulation; rather a number of bodily features, e.g. permanently swollen milk glands and the quality of skin and hair, indicate fitness to breed. Human males also exhibit qualities that are rare among mammals: fertile males can be in the company of fertile females without sex being an imperative--although the awareness of sexuality is generally omnipresent. Moreover, unlike most other Apes, human males can cooperate in large groups, in spite of their polygynic inclination and their tendency to compete with each other for access to females. This capacity probably evolved in response to the necessity to acquire food, in particular meat, which was difficult to obtain by a single man. But life in large, complex, multi-male, multi-female groups places great demands on the members' social skills and, to be able to meet these demands, a large, sophisticated brain (neocortex) is needed. Food (and in its wake, cooking) probably forced man to live in ever-larger groups and to evolve the capacity to cooperate. This, in its turn, drove man's present-days psychosocial (emotional and intellectual) make-up. But for this to evolve, an adaptation of reproductive strategy was a conditio sine qua non.

Maternal Lipid Provisioning Mirrors Evolution of Reproductive Strategies in Direct-Developing Whelks.

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Carrasco, Sergio A; Phillips, Nicole E; Sewell, Mary A

2016-06-01

The energetic input that offspring receive from their mothers is a well-studied maternal effect that can influence the evolution of life histories. Using the offspring of three sympatric whelks: Cominella virgata (one embryo per capsule); Cominella maculosa (multiple embryos per capsule); and Haustrum scobina (multiple embryos per capsule and nurse-embryo consumption), we examined how contrasting reproductive strategies mediate inter- and intraspecific differences in hatchling provisioning. Total lipid content (as measured in μg hatchling(-1) ± SE) was unrelated to size among the 3 species; the hatchlings of H. scobina were the smallest but had the highest lipid content (33.8 ± 8.1 μg hatchling(-1)). In offspring of C. maculosa, lipid content was 6.6 ± 0.4 μg hatchling(-1), and in offspring of C. virgata, it was 21.7 ± 3.2 μg hatchling(-1) The multi-encapsulated hatchlings of C. maculosa and H. scobina were the only species that contained the energetic lipids, wax ester (WE) and methyl ester (ME). However, the overall composition of energetic lipid between hatchlings of the two Cominella species reflected strong affinities of taxonomy, suggesting a phylogenetic evolution of the non-adelphophagic development strategy. Inter- and intracapsular variability in sibling provisioning was highest in H. scobina, a finding that implies less control of allocation to individual hatchlings in this adelphophagic developer. We suggest that interspecific variability of lipids offers a useful approach to understanding the evolution of maternal provisioning in direct-developing species. © 2016 Marine Biological Laboratory.

An integrated control strategy for the composite braking system of an electric vehicle with independently driven axles

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Sun, Fengchun; Liu, Wei; He, Hongwen; Guo, Hongqiang

2016-08-01

For an electric vehicle with independently driven axles, an integrated braking control strategy was proposed to coordinate the regenerative braking and the hydraulic braking. The integrated strategy includes three modes, namely the hybrid composite mode, the parallel composite mode and the pure hydraulic mode. For the hybrid composite mode and the parallel composite mode, the coefficients of distributing the braking force between the hydraulic braking and the two motors' regenerative braking were optimised offline, and the response surfaces related to the driving state parameters were established. Meanwhile, the six-sigma method was applied to deal with the uncertainty problems for reliability. Additionally, the pure hydraulic mode is activated to ensure the braking safety and stability when the predictive failure of the response surfaces occurs. Experimental results under given braking conditions showed that the braking requirements could be well met with high braking stability and energy regeneration rate, and the reliability of the braking strategy was guaranteed on general braking conditions.

Enhancing the light-driven production of D-lactate by engineering cyanobacterium using a combinational strategy

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Li, Chao; Tao, Fei; Ni, Jun; Wang, Yu; Yao, Feng; Xu, Ping

2015-05-01

It is increasingly attractive to engineer cyanobacteria for bulk production of chemicals from CO2. However, cofactor bias of cyanobacteria is different from bacteria that prefer NADH, which hampers cyanobacterial strain engineering. In this study, the key enzyme D-lactate dehydrogenase (LdhD) from Lactobacillus bulgaricus ATCC11842 was engineered to reverse its favored cofactor from NADH to NADPH. Then, the engineered enzyme was introduced into Synechococcus elongatus PCC7942 to construct an efficient light-driven system that produces D-lactic acid from CO2. Mutation of LdhD drove a fundamental shift in cofactor preference towards NADPH, and increased D-lactate productivity by over 3.6-fold. We further demonstrated that introduction of a lactic acid transporter and bubbling CO2-enriched air also enhanced D-lactate productivity. Using this combinational strategy, increased D-lactate concentration and productivity were achieved. The present strategy may also be used to engineer cyanobacteria for producing other useful chemicals.

Reproduction in the endangered African wild dog: basic physiology, reproductive suppression and possible benefits of artificial insemination.

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Van den Berghe, F; Paris, D B B P; Van Soom, A; Rijsselaere, T; Van der Weyde, L; Bertschinger, H J; Paris, M C J

2012-07-01

The African wild dog (Lycaon pictus) is an endangered exotic canid with less than 5500 animals remaining in the wild. Despite numerous strategies to conserve this species, numbers of free-living animals are in decline. It is a highly social species with a complex pack structure: separate male and female dominant hierarchies with, typically, participation of subdominant adults in the rearing of the dominant breeding pairs' pups. Basic reproductive knowledge is largely missing in this species, with only limited information available on the profile of reproductive hormones, based on non-invasive endocrine monitoring. The dominant or alpha male and female are reproductively active and the subdominants are generally reproductively suppressed. However, the occasional production of litters by subdominant females and evidence of multiple paternity within litters suggests that fertility of subordinates is not completely inhibited. In this respect, there are still considerable gaps in our knowledge about the mechanisms governing reproduction and reproductive suppression in African wild dogs, particularly the influence of dominance and pack structure on both male and female fertility. Given concerns over the long-term survival of this species, further research in this area is essential to provide valuable information for their captive breeding and conservation. Reproductive information can also be applied to the development of Assisted Reproductive Techniques for this species; the utility of which in African wild dog conservation is also discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

A greater decline in female facial attractiveness during middle age reflects women’s loss of reproductive value

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Dario eMaestripieri

2014-02-01

Full Text Available Facial attractiveness represents an important component of an individual’s overall attractiveness as a potential mating partner. Perceptions of facial attractiveness are expected to vary with age-related changes in health, reproductive value, and power. In this study, we investigated perceptions of facial attractiveness, power, and personality in two groups of women of pre- and post-menopausal ages (35-50 years and 51-65 years, respectively and two corresponding groups of men. We tested three hypotheses: 1 that perceived facial attractiveness would be lower for older than for younger men and women; 2 that the age-related reduction in facial attractiveness would be greater for women than for men; and 3 that for men, there would be a larger increase in perceived power at older ages. Eighty facial stimuli were rated by 60 (30 male, 30 female middle-aged women and men using online surveys. Our three main hypotheses were supported by the data. Consistent with sex differences in mating strategies, the greater age-related decline in female facial attractiveness was driven by male respondents, while the greater age-related increase in male perceived power was driven by female respondents. In addition, we found evidence that some personality ratings were correlated with perceived attractiveness and power ratings. The results of this study are consistent with evolutionary theory and with previous research showing that faces can provide important information about characteristics that men and women value in a potential mating partner such as their health, reproductive value, and power or possession of resources.

The Use of Proteomics in Assisted Reproduction.

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Kosteria, Ioanna; Anagnostopoulos, Athanasios K; Kanaka-Gantenbein, Christina; Chrousos, George P; Tsangaris, George T

2017-01-01

Despite the explosive increase in the use of Assisted Reproductive Technologies (ART) over the last 30 years, their success rates remain suboptimal. Proteomics is a rapidly-evolving technology-driven science that has already been widely applied in the exploration of human reproduction and fertility, providing useful insights into its physiology and leading to the identification of numerous proteins that may be potential biomarkers and/or treatment targets of a successful ART pregnancy. Here we present a brief overview of the techniques used in proteomic analyses and attempt a comprehensive presentation of recent data from mass spectrometry-based proteomic studies in humans, regarding all components of ARTs, including the male and female gamete, the derived zygote and embryo, the endometrium and, finally, the ART offspring both pre- and postnatally. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Health Literacy and Women's Reproductive Health: A Systematic Review

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Vitko, Michelle; O'Conor, Rachel; Bailey, Stacy Cooper

2016-01-01

Abstract Background: Health literacy is thought to impact women's reproductive health, yet no comprehensive systematic reviews have been conducted on the topic. Our objective was to systematically identify, investigate, and summarize research on the relationship between health literacy and women's reproductive health knowledge, behaviors, and outcomes. Methods: PRISMA guidelines were used to guide this review. English language, peer-reviewed research articles indexed in MEDLINE as of February 2015 were searched, along with study results posted on Clinicaltrials.gov. Articles were included if they (1) described original data-driven research conducted in developed countries, (2) were published in a peer-reviewed journal, (3) measured health literacy using a validated assessment, (4) reported on the relationship between health literacy and reproductive health outcomes, related knowledge, or behaviors, and (5) consisted of a study population that included reproductive age women. Results: A total of 34 articles met eligibility criteria and were included in this review. Data were abstracted from articles by two study authors using a standardized form. Abstracted data were then reviewed and summarized in table format. Overall, health literacy was associated with reproductive health knowledge across a spectrum of topics. It was also related to certain health behaviors, such as prenatal vitamin use and breastfeeding. Its relationship with other reproductive behaviors and outcomes remains unclear. Conclusions: Health literacy plays an important role in reproductive knowledge and may impact behaviors and outcomes. While further research is necessary, healthcare providers should utilize health literacy best practices now to promote high-quality care for patients. PMID:27564780

A conrparison of optirnunl and maximum reproduction using the rat ...

African Journals Online (AJOL)

of pigs to increase reproduction rate of sows (te Brake,. 1978; Walker et at., 1979; Kemm et at., 1980). However, no experimental evidence exists that this strategy would in fact improve biological efficiency. In this pilot experiment, an attempt was made to compare systems of optimum or maximum reproduction using the rat.

Sex, drugs and moral goals: reproductive strategies and views about recreational drugs

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Kurzban, Robert; Dukes, Amber; Weeden, Jason

2010-01-01

Humans, unlike most other species, show intense interest in the activities of conspecifics, even when the activities in question pose no obvious fitness threat or opportunity. Here, we investigate one content domain in which people show substantial interest, the use of drugs for non-medical purposes. Drawing from two subject populations—one undergraduate and one Internet-based—we look at the relationships among (i) abstract political commitments; (ii) attitudes about sexuality; and (iii) views surrounding recreational drugs. Whereas some theories suggest that drug views are best understood as the result of abstract political ideology, we suggest that these views can be better understood in the context of reproductive strategy. We show that, as predicted by a strategic construal, drug attitudes are best predicted by sexual items rather than abstract political commitments and, further, that the relationship between factors such as political ideology and drugs, while positive, are reduced to zero or nearly zero when items assessing sexuality are controlled for. We conclude that considering morality from the standpoint of strategic interests is a potentially useful way to understand why humans care about third party behaviour. PMID:20554547

Economic Comparison of an Empirical Versus Diagnostic-Driven Strategy for Treating Invasive Fungal Disease in Immunocompromised Patients.

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Barnes, Rosemary; Earnshaw, Stephanie; Herbrecht, Raoul; Morrissey, Orla; Slavin, Monica; Bow, Eric; McDade, Cheryl; Charbonneau, Claudie; Weinstein, David; Kantecki, Michal; Schlamm, Haran; Maertens, Johan

2015-06-01

Patients with persistent or recurrent neutropenic fevers at risk of invasive fungal disease (IFD) are treated empirically with antifungal therapy (AFT). Early treatment using a diagnostic-driven (DD) strategy may reduce clinical and economic burdens. We compared costs and outcomes of both strategies from a UK perspective. An empirical strategy with conventional amphotericin B deoxycholate (C-AmB), liposomal amphotericin B (L-AmB), or caspofungin was compared with a DD strategy (initiated based on positive ELISA results for galactomannan antigen) and/or positive results for Aspergillus species on polymerase chain reaction assay) using C-AmB, voriconazole, or L-AmB in a decision-analytic model. Rates of IFD incidence, overall mortality, and IFD-related mortality in adults expected to be neutropenic for ≥10 days were obtained. The empirical strategy was assumed to identify 30% of IFD and targeted AFT to improve survival by a hazard ratio of 0.589. AFT-specific adverse events were obtained from a summary of product characteristics. Resource use was obtained, and costs were estimated by using standard UK costing sources. All costs are presented in 2012 British pounds sterling. Total costs were 32% lower for the DD strategy (£1561.29) versus the empirical strategy (£2301.93) due to a reduced incidence of adverse events and decreased use of AFT. Administration of AFT was reduced by 41% (DD strategy, 74 of 1000; empirical strategy, 125 of 1000), with similar survival rates. This study suggests that a DD strategy is likely to be cost-saving versus empirical treatment for immunocompromised patients with persistent or recurrent neutropenic fevers. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Natural methods for increasing reproductive efficiency in small ruminants.

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Martin, G B; Milton, J T B; Davidson, R H; Banchero Hunzicker, G E; Lindsay, D R; Blache, D

2004-07-01

This paper describes three strategies to improve the reproductive performance of small ruminants in ways that lead to "clean, green and ethical" animal production. The first is aimed at control of the timing of reproductive events for which we turn to the socio-sexual inputs of the "male effect" to induce synchronised ovulation in females that would otherwise be anovulatory. The second strategy, "focussed feeding", is based on our knowledge of the responses to nutrition and aims to develop short programs of nutritional supplements that are precisely timed and specifically designed for individual events in the reproductive process, such as gamete production, embryo survival, fetal programming and colostrum production. The third strategy aims to maximise offspring survival by a combination of management, nutrition and genetic selection for behavior (temperament). All of these approaches involve non-pharmacological manipulation of the endogenous control systems of the animals and complement the detailed information from ultrasound that is now becoming available. The use of such clean, green and ethical tools in the management of our animals can be cost-effective, increase productivity and, at the same time, greatly improve the image of meat and milk industries in society and the marketplace.

Star marketer’s impact on the market strategy choice

Directory of Open Access Journals (Sweden)

Vlašić Goran

2017-01-01

Full Text Available We focus on understanding the role of star marketers in pursuing a market-driven vs. a market-driving strategy. Results indicate that market-driving and market-driven strategies are two approaches that can be pursued by market-oriented firms. A star marketer has a robust positive influence on market-driving strategy. In contrast, a star marketer has no meaningful influence on market-driven strategy. In short, while star marketers are very important for market-driving strategy and long term success, they represent an unnecessary cost and provide no added value to companies focusing on market-driven strategies and short term results.

Endocrine control of epigenetic mechanisms in male reproduction.

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Ankolkar, Mandar; Balasinor, N H

2016-01-01

Endocrine control of reproduction is very well known and has been echoed by many research groups. However, recent developments point to the ability of toxic endocrine disrupting chemicals (EDC) to alter epigenetic information of the gametes which gets transferred to the developing embryo and affects the immediate reproductive outcome or even persists transgenerationally. These epigenetic aberrations contribute to the ensuing pathophysiology of reproductive disorders. Investigations of the female in cases of poor reproductive outcome have been the main strategy towards diagnosis. However, despite the male partner contributing half of his genome to the progeny, thorough investigations in the male have been ignored. Environmental pollutants are all pervading and are encountered in our day-to-day life. Many of these pollutants have potential to disrupt the endocrine system. Here, we discuss how the male gametes (spermatozoa) are susceptible to a myriad of epigenetic insults inflicted by exposure to endocrine disruptors and how important is the contribution of the epigenetic marks of the spermatozoa in healthy reproduction. We advocate that sperm epigenetics should be considered as a significant contributor to reproductive health and should be researched further and be subsequently included in routine diagnostic workup in cases of poor reproductive outcome.

Dental Providers’ Perspectives on Diagnosis-Driven Dentistry: Strategies to Enhance Adoption of Dental Diagnostic Terminology

Science.gov (United States)

Obadan-Udoh, Enihomo; Etolue, Jini; Tokede, Oluwabunmi; White, Joel; Spallek, Heiko; Walji, Muhammad; Kalenderian, Elsbeth

2017-01-01

The routine use of standardized diagnostic terminologies (DxTMs) in dentistry has long been the subject of academic debate. This paper discusses the strategies suggested by a group of dental stakeholders to enhance the uptake of DxTMs. Through unstructured interviewing at the ‘Toward a Diagnosis-Driven Profession’ National Conference held on 19 March 2016 in Los Angeles, CA, USA participants were asked how enthusiastic they were about implementing and consistently using DxTMs at their work. They also brainstormed on strategies to improve the widespread use of DxTMs. Their responses are summarized by recursive abstraction and presented in themes. Conference participants were very enthusiastic about using a DxTM in their place of work. Participants enumerated several strategies to make DxTMs more appealing including: the use of mandates, a value proposition for providers, communication and education, and integration with EHRs and existing systems. All groups across the dental healthcare delivery spectrum will need to work together for the success of the widespread and consistent use of DxTMs. Understanding the provider perspective is however the most critical step in achieving this goal, as they are the group who will ultimately be saddled with the critical task of ensuring DxTM use at the point of care. PMID:28703751

Dental Providers' Perspectives on Diagnosis-Driven Dentistry: Strategies to Enhance Adoption of Dental Diagnostic Terminology.

Science.gov (United States)

Obadan-Udoh, Enihomo; Simon, Lisa; Etolue, Jini; Tokede, Oluwabunmi; White, Joel; Spallek, Heiko; Walji, Muhammad; Kalenderian, Elsbeth

2017-07-13

The routine use of standardized diagnostic terminologies (DxTMs) in dentistry has long been the subject of academic debate. This paper discusses the strategies suggested by a group of dental stakeholders to enhance the uptake of DxTMs. Through unstructured interviewing at the 'Toward a Diagnosis-Driven Profession' National Conference held on 19 March 2016 in Los Angeles, CA, USA participants were asked how enthusiastic they were about implementing and consistently using DxTMs at their work. They also brainstormed on strategies to improve the widespread use of DxTMs. Their responses are summarized by recursive abstraction and presented in themes. Conference participants were very enthusiastic about using a DxTM in their place of work. Participants enumerated several strategies to make DxTMs more appealing including: the use of mandates, a value proposition for providers, communication and education, and integration with EHRs and existing systems. All groups across the dental healthcare delivery spectrum will need to work together for the success of the widespread and consistent use of DxTMs. Understanding the provider perspective is however the most critical step in achieving this goal, as they are the group who will ultimately be saddled with the critical task of ensuring DxTM use at the point of care.

Antidiabetic therapies and male reproductive function: where do we stand?

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Tavares, R S; Escada-Rebelo, S; Silva, A F; Sousa, M I; Ramalho-Santos, J; Amaral, S

2018-01-01

Diabetes mellitus has been increasing at alarming rates in recent years, thus jeopardizing human health worldwide. Several antidiabetic drugs have been introduced in the market to manage glycemic levels, and proven effective in avoiding, minimizing or preventing the appearance or development of diabetes mellitus-related complications. However, and despite the established association between such pathology and male reproductive dysfunction, the influence of these therapeutic interventions on such topics have been scarcely explored. Importantly, this pathology may contribute toward the global decline in male fertility, giving the increasing preponderance of diabetes mellitus in young men at their reproductive age. Therefore, it is mandatory that the reproductive health of diabetic individuals is maintained during the antidiabetic treatment. With this in mind, we have gathered the available information and made a critical analysis regarding the effects of several antidiabetic drugs on male reproductive function. Unlike insulin, which has a clear and fundamental role on male reproductive function, the other antidiabetic therapies' effects at this level seem incoherent. In fact, studies are highly controversial possibly due to the different experimental study approaches, which, in our opinion, suggests caution when it comes to prescribing such drugs to young diabetic patients. Overall, much is still to be determined and further studies are needed to clarify the safety of these antidiabetic strategies on male reproductive system. Aspects such as the effects of insulin levels variations, consequent of insulin therapy, as well as what will be the impact of the side effect hypoglycemia, common to several therapeutic strategies discussed, on the male reproductive system are still to be addressed. © 2018 Society for Reproduction and Fertility.

Male-driven reproductive and agonistic character displacement in darters and its implications for speciation in allopatry

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Fuller, Rebecca C

2018-01-01

Abstract Selection against hybridization can cause mating traits to diverge between species in sympatry via reproductive character displacement (RCD). Additionally, selection against interspecific fighting can cause aggressive traits to diverge between sympatric species via agonistic character displacement (ACD). By directly affecting conspecific recognition traits, RCD and ACD between species can also incidentally cause divergence in mating and fighting traits among populations within a species [termed cascade RCD (CRCD) and cascade ACD]. Here, we demonstrate patterns consistent with male-driven RCD and ACD in 2 groups of darters (orangethroat darter clade Ceasia and rainbow darter Etheostoma caeruleum). In both groups, males that occur in sympatry (between Ceasia and E. caeruleum) have higher levels of preference for mating and fighting with conspecifics over heterospecifics than do males from allopatry. This is consistent with RCD and ACD. We also found patterns consistent with CRCD and cascade ACD among species of Ceasia. Ceasia males that are sympatric to E. caeruleum (but allopatric to one another) also have heightened preferences for mating and fighting with conspecific versus heterospecific Ceasia. In contrast, Ceasia males that are allopatric to E. caeruleum readily mate and fight with heterospecific Ceasia. We suggest that RCD and ACD between Ceasia and E. caeruleum has incidentally led to divergence in mating and fighting traits among Ceasia species. This study is unique in that male preferences evolve via both RCD (male preference for conspecific females) and ACD (male preference to fight conspecific males) which leads to subsequent divergence among allopatric lineages. PMID:29492043

Perspective on a Modified Developmental and Reproductive Toxicity Testing Strategy for Cancer Immunotherapy.

Science.gov (United States)

Prell, Rodney A; Halpern, Wendy G; Rao, Gautham K

2016-05-01

The intent of cancer immunotherapy (CIT) is to generate and enhance T-cell responses against tumors. The tumor microenvironment establishes several inhibitory pathways that lead to suppression of the local immune response, which is permissive for tumor growth. The efficacy of different CITs, alone and in combination, stems from reinvigorating the tumor immune response via several mechanisms, including costimulatory agonists, checkpoint inhibitors, and vaccines. However, immune responses to other antigens (self and foreign) may also be enhanced, resulting in potentially undesired effects. In outbred mammalian pregnancies, the fetus expresses paternally derived alloantigens that are recognized as foreign by the maternal immune system. If unchecked or enhanced, maternal immunity to these alloantigens represents a developmental and reproductive risk and thus is a general liability for cancer immunotherapeutic molecules. We propose a tiered approach to confirm this mechanistic reproductive liability for CIT molecules. A rodent allopregnancy model is based on breeding 2 different strains of mice so that paternally derived alloantigens are expressed by the fetus. When tested with a cross-reactive biotherapeutic, small molecule drug, or surrogate molecule, this model should reveal on-target reproductive liabilities if the pathway is involved in maintaining pregnancy. Alternatively, allopregnancy models with genetically modified mice can be interrogated for exquisitely specific biotherapeutics with restricted species reactivity. The allopregnancy model represents a relatively straightforward approach to confirm an expected on-target reproductive risk for CIT molecules. For biotherapeutics, it could potentially replace more complex developmental and reproductive toxicity testing in nonhuman primates when a pregnancy hazard is confirmed or expected. © The Author(s) 2016.

Gender and social reproduction: historical perspectives.

Science.gov (United States)

Laslett, B; Brenner, J

1989-01-01

It is argued that gender relations and social reproduction were both shaped by macrohistorical processes and shaped the processes. Social reproduction is defined within feminist theory as more than production in the Marxist sense. Societal reproduction is a combination of the organization of production, the organization of social reproduction, the perpetuation of gender, and the continuation of class relations. Social reproduction includes the care and socialization of children and care of the elderly or infirm. Social reproduction includes the organization of sexuality, biological reproduction, and how food, clothing, and shelter are made available. Most social reproduction occurs within the family unit. It is pointed out that variations in the distribution of the work of social reproduction are affected by the family, market, community, and state. The ways in which women construct their own worlds of activity is a central concern. The feminist concept of social reproduction differs from modernization theory, which is concerned with the institutional location of the tasks of social reproduction and the structural effects on the family and gender relations. This literature review focuses only on the history of family strategies and separate gender-related activities. The authors describe the changes in family organization that define men as income producers and women as caretakers, who base child rearing on love and feminine virtue rather than patriarchal authority and religious doctrine. The discussion focuses on the differences in marital relationships, motherhood, and sexuality between upper and middle class and working class women in the 19th century. Among working class women, a good wife was an efficient manager, a skilled domestic worker, and an income earner. The turn of the century was a period of social change marked by smaller average family size, the decline of household production, the rise in real wages, and increased consumption. It is argued that

Rethinking reproductive "tourism" as reproductive "exile".

Science.gov (United States)

Inhorn, Marcia C; Patrizio, Pasquale

2009-09-01

Whereas reproductive "tourism" implies leisure travel, reproductive "exile" bespeaks the numerous difficulties and constraints faced by infertile patients who are "forced" to travel globally for assisted reproduction. Given this reality, it is time to rethink the language of "reproductive tourism," replacing it with more accurate and patient-centered terms.

Reproductive biology and its impact on body size: comparative analysis of mammalian, avian and dinosaurian reproduction.

Science.gov (United States)

Werner, Jan; Griebeler, Eva Maria

2011-01-01

Janis and Carrano (1992) suggested that large dinosaurs might have faced a lower risk of extinction under ecological changes than similar-sized mammals because large dinosaurs had a higher potential reproductive output than similar-sized mammals (JC hypothesis). First, we tested the assumption underlying the JC hypothesis. We therefore analysed the potential reproductive output (reflected in clutch/litter size and annual offspring number) of extant terrestrial mammals and birds (as "dinosaur analogs") and of extinct dinosaurs. With the exception of rodents, the differences in the reproductive output of similar-sized birds and mammals proposed by Janis and Carrano (1992) existed even at the level of single orders. Fossil dinosaur clutches were larger than litters of similar-sized mammals, and dinosaur clutch sizes were comparable to those of similar-sized birds. Because the extinction risk of extant species often correlates with a low reproductive output, the latter difference suggests a lower risk of population extinction in dinosaurs than in mammals. Second, we present a very simple, mathematical model that demonstrates the advantage of a high reproductive output underlying the JC hypothesis. It predicts that a species with a high reproductive output that usually faces very high juvenile mortalities will benefit more strongly in terms of population size from reduced juvenile mortalities (e.g., resulting from a stochastic reduction in population size) than a species with a low reproductive output that usually comprises low juvenile mortalities. Based on our results, we suggest that reproductive strategy could have contributed to the evolution of the exceptional gigantism seen in dinosaurs that does not exist in extant terrestrial mammals. Large dinosaurs, e.g., the sauropods, may have easily sustained populations of very large-bodied species over evolutionary time.

Reproductive Biology and Its Impact on Body Size: Comparative Analysis of Mammalian, Avian and Dinosaurian Reproduction

Science.gov (United States)

Werner, Jan; Griebeler, Eva Maria

2011-01-01

Janis and Carrano (1992) suggested that large dinosaurs might have faced a lower risk of extinction under ecological changes than similar-sized mammals because large dinosaurs had a higher potential reproductive output than similar-sized mammals (JC hypothesis). First, we tested the assumption underlying the JC hypothesis. We therefore analysed the potential reproductive output (reflected in clutch/litter size and annual offspring number) of extant terrestrial mammals and birds (as “dinosaur analogs”) and of extinct dinosaurs. With the exception of rodents, the differences in the reproductive output of similar-sized birds and mammals proposed by Janis and Carrano (1992) existed even at the level of single orders. Fossil dinosaur clutches were larger than litters of similar-sized mammals, and dinosaur clutch sizes were comparable to those of similar-sized birds. Because the extinction risk of extant species often correlates with a low reproductive output, the latter difference suggests a lower risk of population extinction in dinosaurs than in mammals. Second, we present a very simple, mathematical model that demonstrates the advantage of a high reproductive output underlying the JC hypothesis. It predicts that a species with a high reproductive output that usually faces very high juvenile mortalities will benefit more strongly in terms of population size from reduced juvenile mortalities (e.g., resulting from a stochastic reduction in population size) than a species with a low reproductive output that usually comprises low juvenile mortalities. Based on our results, we suggest that reproductive strategy could have contributed to the evolution of the exceptional gigantism seen in dinosaurs that does not exist in extant terrestrial mammals. Large dinosaurs, e.g., the sauropods, may have easily sustained populations of very large-bodied species over evolutionary time. PMID:22194835

Reproductive biology and its impact on body size: comparative analysis of mammalian, avian and dinosaurian reproduction.

Directory of Open Access Journals (Sweden)

Jan Werner

Full Text Available Janis and Carrano (1992 suggested that large dinosaurs might have faced a lower risk of extinction under ecological changes than similar-sized mammals because large dinosaurs had a higher potential reproductive output than similar-sized mammals (JC hypothesis. First, we tested the assumption underlying the JC hypothesis. We therefore analysed the potential reproductive output (reflected in clutch/litter size and annual offspring number of extant terrestrial mammals and birds (as "dinosaur analogs" and of extinct dinosaurs. With the exception of rodents, the differences in the reproductive output of similar-sized birds and mammals proposed by Janis and Carrano (1992 existed even at the level of single orders. Fossil dinosaur clutches were larger than litters of similar-sized mammals, and dinosaur clutch sizes were comparable to those of similar-sized birds. Because the extinction risk of extant species often correlates with a low reproductive output, the latter difference suggests a lower risk of population extinction in dinosaurs than in mammals. Second, we present a very simple, mathematical model that demonstrates the advantage of a high reproductive output underlying the JC hypothesis. It predicts that a species with a high reproductive output that usually faces very high juvenile mortalities will benefit more strongly in terms of population size from reduced juvenile mortalities (e.g., resulting from a stochastic reduction in population size than a species with a low reproductive output that usually comprises low juvenile mortalities. Based on our results, we suggest that reproductive strategy could have contributed to the evolution of the exceptional gigantism seen in dinosaurs that does not exist in extant terrestrial mammals. Large dinosaurs, e.g., the sauropods, may have easily sustained populations of very large-bodied species over evolutionary time.

Alcohol production as an adaptive livelihood strategy for women farmers in Tanzania and its potential for unintended consequences on women's reproductive health.

Science.gov (United States)

McCoy, Sandra I; Ralph, Lauren J; Wilson, Wema; Padian, Nancy S

2013-01-01

Although women occupy a central position in agriculture in many developing countries, they face numerous constraints to achieving their full potential including unequal access to assets and limited decision-making authority. We explore the intersection of agricultural livelihoods, food and economic security, and women's sexual and reproductive health in Iringa Region, Tanzania. Our goal was to understand whether the benefits of supporting women in the agricultural sector might also extend to more distal outcomes, including sexual and reproductive health. Using the Sustainable Livelihoods Framework to guide data collection, we conducted 13 focus group discussions (FGD) with female (n = 11) and male farmers (n = 2) and 20 in-depth interviews with agricultural extension officers (n = 10) and village agro-dealers (n = 10). Despite providing the majority of agricultural labor, women have limited control over land and earned income and have little bargaining power. In response to these constraints, women adopt adaptive livelihood strategies, such as alcohol production, that allow them to retain control over income and support their households. However, women's central role in alcohol production, in concert with the ubiquitous nature of alcohol consumption, places them at risk by enhancing their vulnerability to unsafe or transactional sex. This represents a dangerous confluence of risk for female farmers, in which alcohol plays an important role in income generation and also facilitates high-risk sexual behavior. Alcohol production and consumption has the potential to both directly and indirectly place women at risk for undesirable sexual and reproductive health outcomes. Group formation, better access to finance, and engaging with agricultural extension officers were identified as potential interventions for supporting women farmers and challenging harmful gender norms. In addition, joint, multi-sectoral approaches from health and agriculture and

Demographic consequences of greater clonal than sexual reproduction in Dicentra canadensis.

Science.gov (United States)

Lin, Chia-Hua; Miriti, Maria N; Goodell, Karen

2016-06-01

Clonality is a widespread life history trait in flowering plants that may be essential for population persistence, especially in environments where sexual reproduction is unpredictable. Frequent clonal reproduction, however, could hinder sexual reproduction by spatially aggregating ramets that compete with seedlings and reduce inter-genet pollination. Nevertheless, the role of clonality in relation to variable sexual reproduction in population dynamics is often overlooked. We combined population matrix models and pollination experiments to compare the demographic contributions of clonal and sexual reproduction in three Dicentra canadensis populations, one in a well-forested landscape and two in isolated forest remnants. We constructed stage-based transition matrices from 3 years of census data to evaluate annual population growth rates, λ. We used loop analysis to evaluate the relative contribution of different reproductive pathways to λ. Despite strong temporal and spatial variation in seed set, populations generally showed stable growth rates. Although we detected some pollen limitation of seed set, manipulative pollination treatments did not affect population growth rates. Clonal reproduction contributed significantly more than sexual reproduction to population growth in the forest remnants. Only at the well-forested site did sexual reproduction contribute as much as clonal reproduction to population growth. Flowering plants were more likely to transition to a smaller size class with reduced reproductive potential in the following year than similarly sized nonflowering plants, suggesting energy trade-offs between sexual and clonal reproduction at the individual level. Seed production had negligible effects on growth and tuber production of individual plants. Our results demonstrate that clonal reproduction is vital for population persistence in a system where sexual reproduction is unpredictable. The bias toward clonality may be driven by low fitness returns

Reproductive allometry in Pedicularis species changes with elevation

DEFF Research Database (Denmark)

Guo, Hui; Weiner, Jacob; Mazer, Susan J.

2012-01-01

1. Plants produce biomass and then allocate some of it to reproductive structures, so the relationship between reproductive (R) and vegetative (V) mass is a fundamental aspect of a plant’s reproductive strategy. 2. Differences among populations or taxa in the allometric relationship between R and V...... reproductive allocation at smaller sizes and a smaller investment in reproduction per additional unit of biomass accumulated. 3. We investigated variation in the allometric relationship between R and V among 44 naturally occurring populations representing 24 species of Pedicularis in the Tibetan Plateau...... at smaller sizes and less at larger sizes than plants growing at lower elevations. 5. Synthesis. The allometric slope (exponent) of the R–V relationship decreases with increasing elevation among Pedicularis populations and species, reflecting fundamental changes in the costs and benefits of increased...

Anorexia: A "losing" strategy?

Science.gov (United States)

Mealey, L

2000-03-01

Several theorists have tried to model anorexia on Wasser and Barash's (1983) "reproductive suppression model" (RSM). According to the RSM, individual females adaptively suppress their reproductive functioning under conditions of social or physiological stress. From this perspective, mild anorexia is viewed as an adaptive response to modern conditions; more severe anorexia is viewed as an adaptation gone awry. Previous models have not, however, examined the full richness of the RSM. Specifically, Wasser and Barash documented not only self-imposed reproductive suppression, but also manipulative reproductive suppression of subordinate females by dominants. I propose that the modern "epidemic" of anorexia is explained neither by adaptive self-suppression nor by environmental mismatch (an adaptation gone awry); I propose that the "epidemic" levels of anorexia seen in modern western society are a direct consequence of intrasexual competition, the scope of which has been enhanced by the power and reach of modern communications media. According to this perspective, anorexia, even in its mild forms, is a manipulative strategy imposed on subordinates by dominants. Anorexia is, in both senses, a "losing" strategy.

Meat intake and reproductive parameters among young men

DEFF Research Database (Denmark)

Afeiche, Myriam C; Williams, Paige L; Gaskins, Audrey J

2014-01-01

interval = -67 to 37), -14 (-82 to 28), and -78 (-202 to -5) million (test for trend, P = 0.01). This association was strongest among men with abstinence time less than 2 days and was driven by a strong inverse relation between processed red meat intake and ejaculate volume (test for trend, P = 0......BACKGROUND: In the United States, anabolic sex steroids are administered to cattle for growth promotion. There is concern regarding the reproductive consequences of this practice in men who eat beef. We investigated whether meat consumption was associated with semen quality parameters...... and reproductive hormone levels in young men. METHODS: Semen samples were obtained from 189 men aged 18-22 years. Diet was assessed with a previously validated food frequency questionnaire. We used linear regression to analyze the cross-sectional associations of meat intake with semen quality parameters...

Star marketer’s impact on the market strategy choice

OpenAIRE

Goran, Vlašić; Hair, Joe F.; Krupka, Zoran

2017-01-01

We focus on understanding the role of star marketers in pursuing a market-driven vs. a market-driving strategy. Results indicate that market-driving and market-driven strategies are two approaches that can be pursued by market-oriented firms. A star marketer has a robust positive influence on market-driving strategy. In contrast, a star marketer has no meaningful influence on market-driven strategy. In short, while star marketers are very important for market-driving strategy and long term su...

Protein and glucogenic precursor supplementation: a nutritional strategy to increase reproductive and economic output.

Science.gov (United States)

Mulliniks, J T; Cox, S H; Kemp, M E; Endecott, R L; Waterman, R C; Vanleeuwen, D M; Torell, L A; Petersen, M K

2011-10-01

Reproductive performance in young beef cows is often compromised due to a mismatch of physiological demands and suboptimal environmental conditions. Studies conducted at the Corona Range and Livestock Research Center from 2000 to 2007 evaluated 3 postpartum supplement strategies that varied in the amount of glucogenic potential (GP) supplied. Reproductive variables, milk production, and serum metabolites were used to assess supplement effectiveness and economics associated with 2- and 3-yr-old beef cows (n = 379) grazing native range. Supplements were individually fed twice/week at 1,135 g/d (2003 to 2004) or 908 g/d (all other years) and provided 1) 327 g of CP, 109 to 118 g of RUP (CON); 2) 327 to 341 g of CP, 142 to 157 g of RUP (RUP); or 3) 327 g of CP, 151 to 173 g of RUP + 40 to 100 g of propionate salt (PS; RUP+PS). Ultimately, total GP for CON, RUP, and RUP+PS was 44 to 47, 57 to 70, and 93 to 141 g, respectively. Blood samples were collected once/week (2000) or twice/week (2001 to 2007) for progesterone analysis to estimate days to resumption of estrus. Cows were exposed to bulls for 60 d or less, and pregnancy was confirmed by rectal palpation at weaning. Days to resumption of estrus after calving decreased linearly (P = 0.02), resulting in an increased pregnancy rate (P = 0.03) with increasing GP. Milk production exhibited a quadratic (P = 0.04) response to increasing GP, with cows fed RUP producing the most amount of milk. However, a linear decrease (P = 0.07) in days from BW nadir to estrus was found with increasing GP. Total kilograms of calf weaned per cow exposed for the supplemental year and subsequent year was increased linearly (P = 0.07) with increased GP. The improvement in pregnancy rate by supplementing RUP+PS resulted in an increase in total revenue of 18% compared with CON-fed cows and 9.5% compared with RUP-fed cows in the subsequent year after supplementation. These data suggest feeding young cows additional GP in the form of PS allows

Strategies for time of culling in control of paratuberculosis in dairy herds.

Science.gov (United States)

Kudahl, A B; Nielsen, S S; Ostergaard, S

2011-08-01

Effect of time for culling cows infected with Mycobacterium avium ssp. paratuberculosis on prevalence and profitability was identified through simulations. Seven test-and-cull strategies with different culling criteria and no attempts to close infection routes were compared with strategies with (1) no control and (2) closure of infection routes and no culling. The effects on true prevalence and gross margin were evaluated in a herd with typical reproduction management (heat detection rate of 38%). This was repeated in a herd with poor reproduction management (heat detection rate of 28%), because poor reproduction leads to lack of replacement animals, which was hypothesized to affect the economic effects of culling. Effects of varying prices of milk, replacement heifers, and hourly wages were also evaluated. The simulated results predicted that immediate culling after the first positive antibody ELISA test would be the most effective culling strategy to reduce prevalence. However, closing transmission routes was even more effective in reducing the prevalence. In the first 3 to 6 yr, all test-and-cull strategies reduced gross margin by US$5 to 55/stall per year. These losses were fully compensated by increased gross margin in yr 6 to 19. In the short run (7 yr with typical reproduction and 10 yr with poor reproduction), it was most profitable to cull test-positive cows when their milk yield decreased below 85% of that expected according to their parity and lactation stage, especially in herds with poor reproduction management. However, this strategy only stabilized the prevalence and did not reduce it. In the long term (>7 yr from implementation of a strategy), it was most profitable to cull cows immediately or as soon as possible after testing positive the first time. Varying milk prices did not affect the ranking between the different culling strategies. Increased market price (20%) of replacement heifers made all culling strategies less profitable and made culling

Wildlife conservation and reproductive cloning.

Science.gov (United States)

Holt, William V; Pickard, Amanda R; Prather, Randall S

2004-03-01

Reproductive cloning, or the production of offspring by nuclear transfer, is often regarded as having potential for conserving endangered species of wildlife. Currently, however, low success rates for reproductive cloning limit the practical application of this technique to experimental use and proof of principle investigations. In this review, we consider how cloning may contribute to wildlife conservation strategies. The cloning of endangered mammals presents practical problems, many of which stem from the paucity of knowledge about their basic reproductive biology. However, situations may arise where resources could be targeted at recovering lost or under-represented genetic lines; these could then contribute to the future fitness of the population. Approaches of this type would be preferable to the indiscriminate generation of large numbers of identical individuals. Applying cloning technology to non-mammalian vertebrates may be more practical than attempting to use conventional reproductive technologies. As the scientific background to cloning technology was pioneered using amphibians, it may be possible to breed imminently threatened amphibians, or even restore extinct amphibian species, by the use of cloning. In this respect species with external embryonic development may have an advantage over mammals as developmental abnormalities associated with inappropriate embryonic reprogramming would not be relevant.

Experimental Study of a natural ventilation strategy in a Full-Scale Enclosure Under Meteorological Conditions: A Buoyancy-Driven Approach

OpenAIRE

Austin, Miguel Chen; Bruneau, Denis; Sempey, Alain; Mora, Laurent; Sommier, Alain

2018-01-01

The performance of a natural ventilation strategy, in a full-scale enclosure under meteorological conditions is studied through an experimental study, a buoyancy-driven approach, by means of the estimation of the air exchange rate per hour and ventilation power. A theoretical and an empirical model are proposed based on the airflow theory in buildings and blower-door tests. A preliminary validation, by comparing our results with standards in air leakage rate determination, is made. The experi...

Adolescent Reproductive Knowledge, Attitudes, and Beliefs and Future Fatherhood.

Science.gov (United States)

Garfield, Craig F; Duncan, Greg; Peters, Sarah; Rutsohn, Joshua; McDade, Thomas W; Adam, Emma K; Coley, Rebekah Levine; Chase-Lansdale, Patricia Lindsay

2016-05-01

With a growing focus on the importance of men's reproductive health, including preconception health, the ways in which young men's knowledge, attitudes, and beliefs (KAB) predict their reproductive paths are understudied. To determine if reproductive KAB predicts fatherhood status, timing and residency (living with child or not). Reproductive KAB and fatherhood outcomes were analyzed from the National Longitudinal Study of Adolescent Health, a 20-year, nationally representative study of individuals from adolescence into adulthood. Four measures of reproductive KAB were assessed during adolescence in waves I and II. A generalized linear latent and mixed model predicted future fatherhood status (nonfather, resident/nonresident father, adolescent father) and timing while controlling for other socio-demographic variables. Of the 10,253 men, 3,425 were fathers (686 nonresident/2,739 resident) by wave IV. Higher risky sexual behavior scores significantly increased the odds of becoming nonresident father (odds ratio [OR], 1.30; p fatherhood and residency status. Strategies that address adolescent males' reproductive KAB are needed in the prevention of unintended reproductive consequences such as early and nonresident fatherhood. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Contrasting reproductive strategies of triploid hybrid males in vertebrate mating systems

Czech Academy of Sciences Publication Activity Database

Pruvost, N. B. M.; Mikulíček, P.; Choleva, Lukáš; Reyer, H. U.

2015-01-01

Roč. 28, č. 1 (2015), s. 189-204 ISSN 1010-061X Institutional support: RVO:67985904 Keywords : all-hybrid population * asexual reproduction * gamete production * hemiclone * hybridization Subject RIV: EG - Zoology Impact factor: 2.747, year: 2015

Diploidy and the selective advantage for sexual reproduction in unicellular organisms.

Science.gov (United States)

Kleiman, Maya; Tannenbaum, Emmanuel

2009-11-01

This article develops mathematical models describing the evolutionary dynamics of both asexually and sexually reproducing populations of diploid unicellular organisms. The asexual and sexual life cycles are based on the asexual and sexual life cycles in Saccharomyces cerevisiae, Baker's yeast, which normally reproduces by asexual budding, but switches to sexual reproduction when stressed. The mathematical models consider three reproduction pathways: (1) Asexual reproduction, (2) self-fertilization, and (3) sexual reproduction. We also consider two forms of genome organization. In the first case, we assume that the genome consists of two multi-gene chromosomes, whereas in the second case, we consider the opposite extreme and assume that each gene defines a separate chromosome, which we call the multi-chromosome genome. These two cases are considered to explore the role that recombination has on the mutation-selection balance and the selective advantage of the various reproduction strategies. We assume that the purpose of diploidy is to provide redundancy, so that damage to a gene may be repaired using the other, presumably undamaged copy (a process known as homologous recombination repair). As a result, we assume that the fitness of the organism only depends on the number of homologous gene pairs that contain at least one functional copy of a given gene. If the organism has at least one functional copy of every gene in the genome, we assume a fitness of 1. In general, if the organism has l homologous pairs that lack a functional copy of the given gene, then the fitness of the organism is kappa(l). The kappa(l) are assumed to be monotonically decreasing, so that kappa(0) = 1 > kappa(1) > kappa(2) > cdots, three dots, centered > kappa(infinity) = 0. For nearly all of the reproduction strategies we consider, we find, in the limit of large N, that the mean fitness at mutation-selection balance is max{2e(-mu) - 1,0} where N is the number of genes in the haploid set of

Reproductive Strategy and Sexual Conflict Slow Life History Strategy Inihibts Negative Androcentrism

Directory of Open Access Journals (Sweden)

Paul R. Gladden

2013-11-01

Full Text Available Recent findings indicate that a slow Life History (LH strategy factor is associated with increased levels of Executive Functioning (EF, increased emotional intelligence, decreased levels of sexually coercive behaviors, and decreased levels of negative ethnocentrism. Based on these findings, as well as the generative theory, we predicted that slow LH strategy should inhibit negative androcentrism (bias against women. A sample of undergraduates responded to a battery of questionnaires measuring various facets of their LH Strategy, (e.g., sociosexual orientation, mating effort, mate-value, psychopathy, executive functioning, and emotional intelligence and various convergent measures of Negative Androcentrism. A structural model that the data fit well indicated a latent protective LH strategy trait predicted decreased negative androcentrism. This trait fully mediated the relationship between participant biological sex and androcentrism. We suggest that slow LH strategy may inhibit negative attitudes toward women because of relatively decreased intrasexual competition and intersexual conflict among slow LH strategists. DOI: 10.2458/azu_jmmss.v4i1.17774

Effects of a group-based reproductive management extension programme on key management outcomes affecting reproductive performance.

Science.gov (United States)

Brownlie, Tom S; Morton, John M; Heuer, Cord; McDougall, Scott

2015-02-01

A group-based reproductive management extension programme has been designed to help managers of dairy herds improve herd reproductive performance. The aims of this study were, firstly, to assess effects of participation by key decision makers (KDMs) in a farmer action group programme in 2009 and 2010 on six key management outcomes (KMOs) that affect reproductive performance over 2 years (2009-2010 and 2010-2011), and secondly, to describe KDM intentions to change management behaviour(s) affecting each management outcome after participation in the programme. Seasonal calving dairy herds from four regions of New Zealand were enrolled in the study. Intentions to modify management behaviour were recorded using the formal written action plans developed during the extension programme. KMOs assessed were calving pattern of the herd, pre-calving heifer liveweight, pre-calving and premating body condition score (BCS), oestrus detection, anoestrus cow management and bull management. Participation was associated with improvements in heifer liveweight, more heifers calving in the first 6 weeks of the seasonal calving period, premating BCS and oestrus detection. No significant effects were observed on anoestrus cow management or bull management. KDMs with greater numbers of proposed actions had lower 6 week in-calf rates in the second study year than KDMs who proposed fewer actions. A more effective strategy to ensure more appropriate objectives is proposed. Strategies to help KDMs to implement proposed actions more successfully should be investigated to improve the programme further. Copyright © 2014 Elsevier Ltd. All rights reserved.

Sexual reproduction and the evolution of microbial pathogens.

Science.gov (United States)

Heitman, Joseph

2006-09-05

Three common systemic human fungal pathogens--Cryptococcus neoformans, Candida albicans and Aspergillus fumigatus--have retained all the machinery to engage in sexual reproduction, and yet their populations are often clonal with limited evidence for recombination. Striking parallels have emerged with four protozoan parasites that infect humans: Toxoplasma gondii, Trypanosoma brucei, Trypanosoma cruzi and Plasmodium falciparum. Limiting sexual reproduction appears to be a common virulence strategy, enabling generation of clonal populations well adapted to host and environmental niches, yet retaining the ability to engage in sexual or parasexual reproduction and respond to selective pressure. Continued investigation of the sexual nature of microbial pathogens should facilitate both laboratory investigation and an understanding of the complex interplay between pathogens, hosts, vectors, and their environments.

Changing reproductive effort within a semelparous reproductive episode.

Science.gov (United States)

Hughes, P William; Simons, Andrew M

2014-08-01

• Life-history theory predicts a trade-off between current and future reproduction for iteroparous organisms-as individuals age, the expected value of future reproduction declines, and thus reproductive effort is expected to be higher in later clutches than in earlier. In contrast, models explaining the evolution of semelparity treat semelparous reproduction as instantaneous, with no scope for intraindividual variation. However, semelparous reproduction is also extended, but over shorter time scales; whether there are similar age- or stage-specific changes in reproductive effort within a semelparous episode is unclear. In this study, we assessed whether semelparous individuals increase reproductive effort as residual reproductive value declines by comparing the reproductive phenotype of flowers at five different floral positions along a main inflorescence.• Using the herbaceous monocarp Lobelia inflata, we conducted a longitudinal study of 409 individuals including both laboratory and field populations over three seasons. We recorded six reproductive traits-including the length of three phenological intervals as well as fruit size, seed size, and seed number-for all plants across floral positions produced throughout the reproductive episode.• We found that while the rate of flower initiation did not change, flowers at distal (late) floral positions developed more quickly and contained larger seed than flowers at basal (early) floral positions did.• Our results were consistent with the hypothesis that, like iteroparous organisms, L. inflata increases reproductive effort in response to low residual reproductive value. © 2014 Botanical Society of America, Inc.

Human evolution, life history theory, and the end of biological reproduction.

Science.gov (United States)

Last, Cadell

2014-01-01

Throughout primate history there have been three major life history transitions towards increasingly delayed sexual maturation and biological reproduction, as well as towards extended life expectancy. Monkeys reproduce later and live longer than do prosimians, apes reproduce later and live longer than do monkeys, and humans reproduce later and live longer than do apes. These life history transitions are connected to increased encephalization. During the last life history transition from apes to humans, increased encephalization co-evolved with increased dependence on cultural knowledge for energy acquisition. This led to a dramatic pressure for more energy investment in growth over current biological reproduction. Since the industrial revolution socioeconomic development has led to even more energy being devoted to growth over current biological reproduction. I propose that this is the beginning of an ongoing fourth major primate life history transition towards completely delayed biological reproduction and an extension of the evolved human life expectancy. I argue that the only fundamental difference between this primate life history transition and previous life history transitions is that this transition is being driven solely by cultural evolution, which may suggest some deeper evolutionary transition away from biological evolution is already in the process of occurring.

The Potential of Nanotechnology in Medically Assisted Reproduction

Directory of Open Access Journals (Sweden)

Mariana H. Remião

2018-01-01

Full Text Available Reproductive medicine is a field of science which searches for new alternatives not only to help couples achieve pregnancy and preserve fertility, but also to diagnose and treat diseases which can impair the normal operation of the reproductive tract. Assisted reproductive technology (ART is a set of methodologies applied to cases related to infertility. Despite being highly practiced worldwide, ART presents some challenges, which still require special attention. Nanotechnology, as a tool for reproductive medicine, has been considered to help overcome some of those impairments. Over recent years, nanotechnology approaches applied to reproductive medicine have provided strategies to improve diagnosis and increase specificity and sensitivity. For in vitro embryo production, studies in non-human models have been used to deliver molecules to gametes and embryos. The exploration of nanotechnology for ART would bring great advances. In this way, experiments in non-human models to test the development and safety of new protocols using nanomaterials are very important for informing potential future employment in humans. This paper presents recent developments in nanotechnology regarding impairments still faced by ART: ovary stimulation, multiple pregnancy, and genetic disorders. New perspectives for further use of nanotechnology in reproductive medicine studies are also discussed.

Chronic pelvic pain in women of reproductive and post-reproductive age: a population-based study.

Science.gov (United States)

Ayorinde, A A; Bhattacharya, S; Druce, K L; Jones, G T; Macfarlane, G J

2017-03-01

Epidemiological studies on chronic pelvic pain (CPP) have focused on women of reproductive age. We aimed to determine the prevalence of chronic pelvic pain (CPP) in adult women and the differences in associated factors among women of reproductive age and older women. In addition, to determine whether distinct subgroups existed among CPP cases. A cross-sectional postal survey was conducted among 5300 randomly selected women aged ≥25 years resident in the Grampian region, UK. Multivariable logistic regression was used to determine pregnancy-related and psychosocial factors associated with CPP. To identify subgroups of CPP cases, we performed cluster analysis using variables of pain severity, psychosocial factors and pain coping strategies. Of 2088 participants, 309 (14.8%) reported CPP. CPP was significantly associated with being of reproductive age (odds ratios (OR) 2.43, 95% CI 1.69-3.48), multiple non-pain somatic symptoms (OR 3.58 95% CI 2.23-5.75), having fatigue (OR mild 1.74 95% CI 1.24-2.44, moderate/severe 1.82, 95% CI 1.25-2.63) and having depression (OR 1.61, 95% CI 1.09-2.38). CPP was less associated with multiple non-pain somatic symptoms in women of reproductive age compared to older women (interaction OR 0.51, 95% CI 0.28-0.92). We identified two clusters of CPP cases; those having little/no psychosocial distress and those having high psychosocial distress. CPP is common in both age groups, though women of reproductive age are more likely to report it. Heightened somatic awareness may be more strongly associated with CPP in older women. There are distinct groups of CPP cases characterized by the absence/presence of psychosocial distress. Heightened somatic awareness may be more strongly associated with CPP in women of post-reproductive years compared to women of reproductive years. Two subgroups of CPP cases can be differentiated by the absence/presence of psychosocial distress suggesting that stratified management approach may be more efficient. �

Marxist Perspectives on the Global Enclosures of Social Reproduction

Directory of Open Access Journals (Sweden)

Friederike Beier

2018-05-01

Full Text Available Women’s unpaid care and domestic work is gaining relevance in policy-making as well as in academia. Feminist scholars and activists have lobbied successfully for the integration of unpaid care and domestic work into the Sustainable Development Goals (Goal 5.4 of the United Nations in the hope for greater recognition of women’s contribution to the economy. Policy documents about social reproduction highlight women’s disproportionate share of reproductive activities as an obstacle to women’s economic empowerment and as a relic of ‘traditional’ gender roles. Social reproduction is thereby not understood as a merit in itself, but as an obstacle to women’s participation in paid labour. Policy implications will enable certain empowerment effects for some women, but at the same time promote the increasing privatization and commodification of reproductive work across the globe. Rising inequalities between the Global North and South and between women along the categories of class and race will be one major result. To theoretically explain such contradictory effects of the recognition of social reproduction, I use the concept of ‘enclosures’ based on Marx’ ‘primitive accumulation’. Feminist scholars use the concept to explain how unpaid care and housework is commodified or de-commodified to integrate women into the paid labour force or to reduce the costs of social reproduction according to the needs of the economy. The sudden interest in unpaid care and domestic work e.g. in the Sustainable Development Goals can therefore be seen as process of double enclosure, which integrates women into the paid labour force, but also sets the grounds for the further commodification of domestic and care work. This paper aims to critically discuss the sudden interest in unpaid domestic and care work and its contradictory effects from a Marxist feminist perspective and reflects on feminist strategies and movements in global governance. After

Life-history tradeoffs and reproductive cycles in Spotted Owls

Science.gov (United States)

Stoelting, Ricka E.; Gutierrez, R.J.; Kendall, William L.; Peery, M. Zachariah

2015-01-01

The study of tradeoffs among life-history traits has long been key to understanding the evolution of life-history strategies. However, more recently, evolutionary ecologists have realized that reproductive costs have the potential to influence population dynamics. Here, we tested for costs of reproduction in the California Spotted Owl (Strix occidentalis occidentalis), and assessed whether costs of reproduction in year t − 1 on reproduction in year t could be responsible for regionally synchronized biennial cycles in reproductive output. Logistic regression analysis and multistate mark–recapture models with state uncertainty revealed that breeding reduced the likelihood of reproducing in the subsequent year by 16% to 38%, but had no influence on subsequent survival. We also found that costs of reproduction in year t − 1 were correlated with climatic conditions in year t, with evidence of higher costs during the dry phase of the El Niño–Southern Oscillation. Using a simulation-based population model, we showed that strong reproductive costs had the potential to create biennial cycles in population-level reproductive output; however, estimated costs of reproduction appeared to be too small to explain patterns observed in Spotted Owls. In the absence of strong reproductive costs, we hypothesize that observed natural cycles in the reproductive output of Spotted Owls are related to as-yet-unmeasured, regionally concordant fluctuations in environmental conditions or prey resources. Despite theoretical evidence for demographic effects, our analyses illustrate that linking tradeoffs to actual changes in population processes will be challenging because of the potential confounding effects of individual and environmental variation.

Data-driven batch schuduling

Energy Technology Data Exchange (ETDEWEB)

Bent, John [Los Alamos National Laboratory; Denehy, Tim [GOOGLE; Arpaci - Dusseau, Remzi [UNIV OF WISCONSIN; Livny, Miron [UNIV OF WISCONSIN; Arpaci - Dusseau, Andrea C [NON LANL

2009-01-01

In this paper, we develop data-driven strategies for batch computing schedulers. Current CPU-centric batch schedulers ignore the data needs within workloads and execute them by linking them transparently and directly to their needed data. When scheduled on remote computational resources, this elegant solution of direct data access can incur an order of magnitude performance penalty for data-intensive workloads. Adding data-awareness to batch schedulers allows a careful coordination of data and CPU allocation thereby reducing the cost of remote execution. We offer here new techniques by which batch schedulers can become data-driven. Such systems can use our analytical predictive models to select one of the four data-driven scheduling policies that we have created. Through simulation, we demonstrate the accuracy of our predictive models and show how they can reduce time to completion for some workloads by as much as 80%.

Alcohol production as an adaptive livelihood strategy for women farmers in Tanzania and its potential for unintended consequences on women's reproductive health.

Directory of Open Access Journals (Sweden)

Sandra I McCoy

Full Text Available Although women occupy a central position in agriculture in many developing countries, they face numerous constraints to achieving their full potential including unequal access to assets and limited decision-making authority. We explore the intersection of agricultural livelihoods, food and economic security, and women's sexual and reproductive health in Iringa Region, Tanzania. Our goal was to understand whether the benefits of supporting women in the agricultural sector might also extend to more distal outcomes, including sexual and reproductive health.Using the Sustainable Livelihoods Framework to guide data collection, we conducted 13 focus group discussions (FGD with female (n = 11 and male farmers (n = 2 and 20 in-depth interviews with agricultural extension officers (n = 10 and village agro-dealers (n = 10.Despite providing the majority of agricultural labor, women have limited control over land and earned income and have little bargaining power. In response to these constraints, women adopt adaptive livelihood strategies, such as alcohol production, that allow them to retain control over income and support their households. However, women's central role in alcohol production, in concert with the ubiquitous nature of alcohol consumption, places them at risk by enhancing their vulnerability to unsafe or transactional sex. This represents a dangerous confluence of risk for female farmers, in which alcohol plays an important role in income generation and also facilitates high-risk sexual behavior.Alcohol production and consumption has the potential to both directly and indirectly place women at risk for undesirable sexual and reproductive health outcomes. Group formation, better access to finance, and engaging with agricultural extension officers were identified as potential interventions for supporting women farmers and challenging harmful gender norms. In addition, joint, multi-sectoral approaches from health and agriculture

Estrous synchronization strategies to optimize beef heifer reproductive performance after reproductive tract scoring.

Science.gov (United States)

Kasimanickam, Ramanathan K; Whittier, William D; Hall, John B; Kastelic, John P

2016-08-01

Three experiments comparing four estrous synchronization protocols were conducted to determine estrous expression rate and artificial insemination pregnancy rate (AI-PR) in heifers with a range (1-5) of reproductive tract scores (RTSs). At enrollment (Day 0), 1783 Angus cross beef heifers from six locations were given body condition score and RTS. The four protocols were: (1) HRTS-DPGF group-heifers with RTS 5 received prostaglandin F2α (PGF; Dinoprost 25 mg; im) on Days 0 and 14; (2) HRTS-CIDR-PGF group-heifers with RTS 5 received a CIDR (1.3-g progesterone) insert on Day 7, followed by CIDR removal and PGF on Day 14; (3) LRTS-CIDR-PGF group-heifers with RTS 4 or less received a CIDR insert on Day 7, followed by CIDR removal and PGF on Day 14; and (4) HRTS-Select-Synch group-heifers with RTS 5 received 100 μg of gonadorelin diacetate tetrahydrate (gonadotropin releasing homone; im) on Day 7 and PGF on Day 14. In all groups, heifers observed in estrus were artificially inseminated (within 120 hours after PGF) using the AM-PM rule. In Experiment 1, estrus expression rates were 82.2% (282/343) and 88.5% (184/208) for HRTS-DPGF and LRTS-CIDR-PGF, respectively (P  0.1) and AI-PR were 52.1 (110/211), 60.3 (129/214), and 58.4% (122/209; P > 0.05). In Experiment 3, estrus expression rates were 77.5 (131/169), 85.5 (142/166), and 83.3% (219/263) for HRTS-DPGF, HRTS-Select-Synch and LRTS-CIDR-PGF (P > 0.05) and AI-PR were 53.3 (90/169), 60.2 (100/166), and 58.6% (154/263; P > 0.1). Overall, estrus expression rates for HRTS-DPGF, HRTS-Select-Synch, LRTS-CIDR-PGF, and HRTS-CIDR-PGF groups were 80.4 (581/723), 85.5 (142/166), 85.1 (579/680), and 86.9% (186/214), respectively; higher for heifers in LRTS-CIDR-PGF and HRTS-CIDR-PGF groups compared to heifers in HRTS-DPGF group (P reproductive performance was reduced compared with other protocols used in this study. Copyright © 2016 Elsevier Inc. All rights reserved.

Data-driven strategies for robust forecast of continuous glucose monitoring time-series.

Science.gov (United States)

Fiorini, Samuele; Martini, Chiara; Malpassi, Davide; Cordera, Renzo; Maggi, Davide; Verri, Alessandro; Barla, Annalisa

2017-07-01

Over the past decade, continuous glucose monitoring (CGM) has proven to be a very resourceful tool for diabetes management. To date, CGM devices are employed for both retrospective and online applications. Their use allows to better describe the patients' pathology as well as to achieve a better control of patients' level of glycemia. The analysis of CGM sensor data makes possible to observe a wide range of metrics, such as the glycemic variability during the day or the amount of time spent below or above certain glycemic thresholds. However, due to the high variability of the glycemic signals among sensors and individuals, CGM data analysis is a non-trivial task. Standard signal filtering solutions fall short when an appropriate model personalization is not applied. State-of-the-art data-driven strategies for online CGM forecasting rely upon the use of recursive filters. Each time a new sample is collected, such models need to adjust their parameters in order to predict the next glycemic level. In this paper we aim at demonstrating that the problem of online CGM forecasting can be successfully tackled by personalized machine learning models, that do not need to recursively update their parameters.

The special programme of research in human reproduction: forty years of activities to achieve reproductive health for all.

Science.gov (United States)

Benagiano, Giuseppe; d'Arcangues, Catherine; Harris Requejo, Jennifer; Schafer, Alessandra; Say, Lale; Merialdi, Mario

2012-01-01

The Special Programme of Research in Human Reproduction (HRP), co-sponsored by the UNDP, UNFPA, WHO, and the World Bank, is celebrating 40 years of activities with an expansion of its mandate and new co-sponsors. When it began, in 1972, the main focus was on evaluating the acceptability, effectiveness, and safety of existing fertility-regulating methods, as well as developing new, improved modalities for family planning. In 1994, HRP not only made major contributions to the Plan of Action of the International Conference on Population and Development (ICPD); it also broadened its scope of work to include other aspects of health dealing with sexuality and reproduction, adding a specific perspective on gender issues and human rights. In 2002, HRP's mandate was once again broadened to include sexually transmitted infections and HIV/AIDS and in 2003 it was further expanded to research activities on preventing violence against women and its many dire health consequences. Today, the work of the Programme includes research on: the sexual and reproductive health of adolescents, women, and men; maternal and perinatal health; reproductive tract and sexually transmitted infections (including HIV/AIDS); family planning; infertility; unsafe abortion; sexual health; screening for cancer of the cervix in developing countries, and gender and reproductive rights. Additional activities by the Programme have included: fostering international cooperation in the field of human reproduction; the elaboration of WHO's first Global Reproductive Health Strategy; work leading to the inclusion of ICPD's goal 'reproductive health for all by 2015' into the Millennium Development Goal framework; the promotion of critical interagency statements on the public health, legal, and human rights implications of female genital mutilation and gender-biased sex selection. Finally, HRP has been involved in the creation of guidelines and tools, such as the 'Medical eligibility criteria for contraceptive use

Failure-probability driven dose painting

DEFF Research Database (Denmark)

Vogelius, Ivan R; Håkansson, Katrin; Due, Anne K

2013-01-01

To demonstrate a data-driven dose-painting strategy based on the spatial distribution of recurrences in previously treated patients. The result is a quantitative way to define a dose prescription function, optimizing the predicted local control at constant treatment intensity. A dose planning study...

From Brand Management to Global Business Management in Market-Driven Companies

OpenAIRE

Emilio Zito

2009-01-01

Over the past several years, the most competitive mass-market companies (automobile, high-tech, consumer and retail, etc.) have been experiencing a new strategic approach around the concept of Market-Driven strategy, as opposed to a pure marketing-focused approach known as Customer-Driven strategy. A fast-moving, mass-market global company would likely have a precise performance measurement system in place with broad performance indicators based on: project economics, ratios analysis (ROI, in...

Making a case for a development-driven approach to law as a ...

African Journals Online (AJOL)

driven approach to law as a linchpin for the post-2015 development agenda. KEYWORDS: Law, development, development-driven law, development law, development goals, development strategy, Millennium Development Goals, Millennium ...

Strategies for use of reproductive technologies in genomic dairy cattle breeding programs

DEFF Research Database (Denmark)

Thomasen, Jørn Rind; Sørensen, Anders Christian

A simulation study was performed for testing the effect of using reproductive technologies in a genomic dairy cattle young bull breeding scheme. The breeding scheme parameters: 1) number of donors, 2) number of progeny per donor, 3) age of the donor, 4) number of sires, and 5) reliability...... of genomic breeding values. The breeding schemes were evaluated according to genetic gain and rate of inbreeding. The relative gain by use of reproductive technologies is 11 to 84 percent points depending on the choice of other breeding scheme parameters. A large donor program with high selection intensity...... of sires provides the highest genetic gain. A relatively higher genetic gain is obtained for higher reliability of GEBV. Extending the donor program and number of selected bulls has a major effect of reducing the rate of inbreeding without compromising genetic gain....

Second-Order Multiagent Systems with Event-Driven Consensus Control

Directory of Open Access Journals (Sweden)

Jiangping Hu

2013-01-01

Full Text Available Event-driven control scheduling strategies for multiagent systems play a key role in future use of embedded microprocessors of limited resources that gather information and actuate the agent control updates. In this paper, a distributed event-driven consensus problem is considered for a multi-agent system with second-order dynamics. Firstly, two kinds of event-driven control laws are, respectively, designed for both leaderless and leader-follower systems. Then, the input-to-state stability of the closed-loop multi-agent system with the proposed event-driven consensus control is analyzed and the bound of the inter-event times is ensured. Finally, some numerical examples are presented to validate the proposed event-driven consensus control.

A Conceptual Systems Model to Facilitate Hypothesis-driven Ecotoxicogenomics Research on the Teleost Brain-pituitary-gonadal Axis

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This provides an overview of a novel open-source conceptuial model of molecular and biochemical pathways involved in the regulation of fish reproduction. Further, it provides concrete examples of how such models can be used to design and conduct hypothesis-driven "omics" experim...

Trade-offs between reproductive allocation and storage in species of Oenothera L. (Onagraceae) native to Argentina

Science.gov (United States)

Vilela, Alejandra; Cariaga, Rodrigo; González-Paleo, Luciana; Ravetta, Damián

2008-01-01

A trade-off between reproduction and survival arises because current reproduction diminishes levels of a limiting resource such that less can be placed in storage organs for the survival of an organism during the unfavorable season. Oenothera is a particularly suited genus for studying those kind of trade-offs because it contains species with different life-history strategies (annual, biennial and perennial). Since allocation to leaves is a major factor associated with changes in life-history, here we tested the hypothesis that Oenothera leaf attributes would affect plant reproductive effort and therefore, root reserves. We selected two groups of taxa differing in their leaf area ratio (low- and high-LAR) and we compared their pattern of resource allocation to growth, reproduction and storage. Path analysis confirmed our hypothesis that LAR is the most important variable in explaining variation in allocation to reproduction or storage. The group with high allocation to leaves assigned resources preferentially to storage while the other group allocated more resources to reproduction, as predicted. A trade-off between reproduction and storage was only confirmed for the high-LAR group. The low-LAR group showed the life-history tactic of annual plants, while the high-LAR group exhibited a strategy generally associated with perenniality.

Lectin-functionalized magnetic iron oxide nanoparticles for reproductive improvement

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Background: Semen ejaculates contain heterogeneous sperm populations that can jeopardize male fertility. Recent development of nanotechnology in physiological systems may have applications in reproductive biology. Here, we used magnetic nanoparticles as a novel strategy for sperm purification to imp...

Tales from the "hood:" placing reproductive health communication between African American fathers and children in context.

Science.gov (United States)

Ohalete, Nnenna; Georges, Jane; Doswell, Willa

2010-01-01

To evaluate reproductive health communication between African American fathers and their children. In this qualitative ethnographic study, data were collected through tape-recorded individual interviews about the content and timing of reproductive health communication, the reproductive health values fathers intended to impart to their children, and their comfort level in doing so. A total sample of 19 African-American fathers participated. Data were coded according to the qualitative analytic principles established by Miles and Huberman (1994), and analyzed using manifest and latent content analysis approaches. Although 10 fathers reported feeling uncomfortable having these conversations, 18 reported having reproductive health communication with their children, and most encouraged their sons and daughters to delay sex until adulthood. These conversations were primarily driven by the fear of HIV/AIDS and the negative consequences of sex; however, some conversations were inappropriate for developmental age. African-American fathers may benefit from education to help them have age appropriate reproductive health communication with their children. Registered Nurses and Nurse Practitioners are well positioned to educate African American adolescents and their fathers on reproductive health. Future dyadic African American father-child studies are needed to explore more fully African-American children's perceptions of reproductive health communication and the effect on delaying sex.

Heparin for assisted reproduction.

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Akhtar, Muhammad A; Sur, Shyamaly; Raine-Fenning, Nick; Jayaprakasan, Kannamannadiar; Thornton, Jim G; Quenby, Siobhan

2013-08-17

Heparin as an adjunct in assisted reproduction (peri-implantation heparin) is given at or after egg collection or at embryo transfer during assisted reproduction. Heparin has been advocated to improve embryo implantation and clinical outcomes.  It has been proposed that heparin enhances the intra-uterine environment by improving decidualisation with an associated activation of growth factors and a cytokine expression profile in the endometrium that is favourable to pregnancy. To investigate whether the administration of heparin around the time of implantation (peri-implantation heparin) improves clinical outcomes in subfertile women undergoing assisted reproduction. A comprehensive and exhaustive search strategy was developed in consultation with the Trials Search Co-ordinator of the Cochrane Menstrual Disorders and Subfertility Group (MDSG). The strategy was used in an attempt to identify all relevant studies regardless of language or publication status (published, unpublished, in press, and in progress). Relevant trials were identified from both electronic databases and other resources (last search 6 May 2013). All randomised controlled trials (RCTs) were included where peri-implantation heparin was given during assisted reproduction. Peri-implantation low molecular weight heparin (LMWH) during IVF/ICSI was given at or after egg collection or at embryo transfer in the included studies. Live birth rate was the primary outcome. Two review authors independently assessed the eligibility and quality of trials and extracted relevant data. The quality of the evidence was evaluated using GRADE methods. Three RCTs (involving 386 women) were included in the review.Peri-implantation LMWH administration during assisted reproduction was associated with a significant improvement in live birth rate compared with placebo or no LMWH (odds ratio (OR) 1.77, 95% confidence interval (CI) 1.07 to 2.90, three studies, 386 women, I(2) = 51%, very low quality evidence with high

Control strategies and sensitivity analysis of anthroponotic visceral leishmaniasis model.

Science.gov (United States)

Zamir, Muhammad; Zaman, Gul; Alshomrani, Ali Saleh

2017-12-01

This study proposes a mathematical model of Anthroponotic visceral leishmaniasis epidemic with saturated infection rate and recommends different control strategies to manage the spread of this disease in the community. To do this, first, a model formulation is presented to support these strategies, with quantifications of transmission and intervention parameters. To understand the nature of the initial transmission of the disease, the reproduction number [Formula: see text] is obtained by using the next-generation method. On the basis of sensitivity analysis of the reproduction number [Formula: see text], four different control strategies are proposed for managing disease transmission. For quantification of the prevalence period of the disease, a numerical simulation for each strategy is performed and a detailed summary is presented. Disease-free state is obtained with the help of control strategies. The threshold condition for globally asymptotic stability of the disease-free state is found, and it is ascertained that the state is globally stable. On the basis of sensitivity analysis of the reproduction number, it is shown that the disease can be eradicated by using the proposed strategies.

How cushion communities are maintained in alpine ecosystems: A review and case study on alpine cushion plant reproduction

Directory of Open Access Journals (Sweden)

Jianguo Chen

2017-08-01

Full Text Available Cushion species occur in nearly all alpine environments worldwide. In past decades, the adaptive and ecosystem-engineering roles of such highly specialized life forms have been well studied. However, the adaptive strategies responsible for cushion species reproductive success and maintenance in severe alpine habitats remain largely unclear. In this study, we reviewed the current understanding of reproductive strategies and population persistence in alpine cushion species. We then present a preliminary case study on the sexual reproduction of Arenaria polytrichoides (Caryophyllaceae, a typical cushion species inhabiting high elevations of the Himalaya Hengduan Mountains, which is a hotspot for diversification of cushion species. Finally, we highlight the limitations of our current understanding of alpine cushion species reproduction and propose future directions for study.

Sexual dimorphism in sister species of Leucoraja skate and its relationship to reproductive strategy and life history.

Science.gov (United States)

Martinez, Christopher M; Rohlf, F James; Frisk, Michael G

2016-01-01

Instances of sexual dimorphism occur in a great variety of forms and manifestations. Most skates (Batoidea: Rajoidei) display some level of body shape dimorphism in which the pectoral fins of mature males develop to create a distinct bell-shaped body not found in females. This particular form of dimorphism is present in each of the sister species Leucoraja erinacea and Leucoraja ocellata, but differences between sexes are much greater in the former. In order to understand the nature and potential causes of pectoral dimorphism, we used geometric morphometrics to investigate allometry of fin shape in L. erinacea and L. ocellata and its relationship to the development of reproductive organs, based on previous work on the bonnethead shark, Sphyrna tiburo. We found that allometric trajectories of overall pectoral shape were different in both species of skate, but only L. erinacea varied significantly with respect to endoskeleton development. Male maturation was characterized by a number of sex-specific morphological changes, which appeared concurrently in developmental timing with elongation of cartilage-supported claspers. We suggest that external sexual dimorphism of pectoral fins in skates is a byproduct of skeletal growth needed for clasper development. Further, the magnitude of male shape change appears to be linked to the differential life histories of species. This work reports for the first time that pectoral dimorphism is a persistent feature in rajoid fishes, occurring in varying degrees across several genera. Lastly, our results suggest that pectoral morphology may be useful as a relative indicator of reproductive strategy in some species. © 2016 Wiley Periodicals, Inc.

Role of oxidative stress in female reproduction

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Sharma Rakesh K

2005-07-01

embryopathies, preterm labour and preeclampsia and gestational diabetes. The review also addresses the growing literature on the role of nitric oxide species in female reproduction. The involvement of nitric oxide species in regulation of endometrial and ovarian function, etiopathogenesis of endometriosis, and maintenance of uterine quiescence, initiation of labour and ripening of cervix at parturition is discussed. Complex interplay between cytokines and oxidative stress in the etiology of female reproductive disorders is discussed. Oxidant status of the cell modulates angiogenesis, which is critical for follicular growth, corpus luteum formation endometrial differentiation and embryonic growth is also highlighted in the review. Strategies to overcome oxidative stress and enhance fertility, both natural and assisted are delineated. Early interventions being investigated for prevention of preeclampsia are enumerated. Trials investigating combination intervention strategy of vitamin E and vitamin C supplementation in preventing preeclampsia are highlighted. Antioxidants are powerful and there are few trials investigating antioxidant supplementation in female reproduction. However, before clinicians recommend antioxidants, randomized controlled trials with sufficient power are necessary to prove the efficacy of antioxidant supplementation in disorders of female reproduction. Serial measurement of oxidative stress biomarkers in longitudinal studies may help delineate the etiology of some of the diosorders in female reproduction such as preeclampsia.

Alcohol Production as an Adaptive Livelihood Strategy for Women Farmers in Tanzania and Its Potential for Unintended Consequences on Women’s Reproductive Health

Science.gov (United States)

McCoy, Sandra I.; Ralph, Lauren J.; Wilson, Wema; Padian, Nancy S.

2013-01-01

Background Although women occupy a central position in agriculture in many developing countries, they face numerous constraints to achieving their full potential including unequal access to assets and limited decision-making authority. We explore the intersection of agricultural livelihoods, food and economic security, and women’s sexual and reproductive health in Iringa Region, Tanzania. Our goal was to understand whether the benefits of supporting women in the agricultural sector might also extend to more distal outcomes, including sexual and reproductive health. Methods Using the Sustainable Livelihoods Framework to guide data collection, we conducted 13 focus group discussions (FGD) with female (n = 11) and male farmers (n = 2) and 20 in-depth interviews with agricultural extension officers (n = 10) and village agro-dealers (n = 10). Results Despite providing the majority of agricultural labor, women have limited control over land and earned income and have little bargaining power. In response to these constraints, women adopt adaptive livelihood strategies, such as alcohol production, that allow them to retain control over income and support their households. However, women’s central role in alcohol production, in concert with the ubiquitous nature of alcohol consumption, places them at risk by enhancing their vulnerability to unsafe or transactional sex. This represents a dangerous confluence of risk for female farmers, in which alcohol plays an important role in income generation and also facilitates high-risk sexual behavior. Conclusions Alcohol production and consumption has the potential to both directly and indirectly place women at risk for undesirable sexual and reproductive health outcomes. Group formation, better access to finance, and engaging with agricultural extension officers were identified as potential interventions for supporting women farmers and challenging harmful gender norms. In addition, joint, multi

Fast Mechanically Driven Daughter Cell Separation Is Widespread in Actinobacteria

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Xiaoxue Zhou

2016-08-01

Full Text Available Dividing cells of the coccoid Gram-positive bacterium Staphylococcus aureus undergo extremely rapid (millisecond daughter cell separation (DCS driven by mechanical crack propagation, a strategy that is very distinct from the gradual, enzymatically driven cell wall remodeling process that has been well described in several rod-shaped model bacteria. To determine if other bacteria, especially those in the same phylum (Firmicutes or with similar coccoid shapes as S. aureus, might use a similar mechanically driven strategy for DCS, we used high-resolution video microscopy to examine cytokinesis in a phylogenetically wide range of species with various cell shapes and sizes. We found that fast mechanically driven DCS is rather rare in the Firmicutes (low G+C Gram positives, observed only in Staphylococcus and its closest coccoid relatives in the Macrococcus genus, and we did not observe this division strategy among the Gram-negative Proteobacteria. In contrast, several members of the high-G+C Gram-positive phylum Actinobacteria (Micrococcus luteus, Brachybacterium faecium, Corynebacterium glutamicum, and Mycobacterium smegmatis with diverse shapes ranging from coccoid to rod all undergo fast mechanical DCS during cell division. Most intriguingly, similar fast mechanical DCS was also observed during the sporulation of the actinobacterium Streptomyces venezuelae.

Adverse effects of perinatal nicotine exposure on reproductive outcomes.

Science.gov (United States)

Wong, Michael K; Barra, Nicole G; Alfaidy, Nadia; Hardy, Daniel B; Holloway, Alison C

2015-12-01

Nicotine exposure during pregnancy through cigarette smoking, nicotine replacement therapies or e-cigarette use continues to be a widespread public health problem, impacting both fetal and postnatal health. Yet, at this time, there remains limited data regarding the safety and efficacy in using these nicotine products during pregnancy. Notably, reports assessing the effect of nicotine exposure on postnatal health outcomes in humans, including reproductive health, are severely lacking. Our current understanding regarding the consequences of nicotine exposure during pregnancy is limited to a few animal studies, which do not comprehensively address the underlying cellular mechanisms involved. This paper aims to critically review the current knowledge from human and animal studies regarding the direct and indirect effects (e.g. obesity) of maternal nicotine exposure, regardless of its source, on reproductive outcomes in pregnancy and postnatal life. Furthermore, this review highlights several key cellular mechanisms involved in these adverse reproductive deficits including oxidative stress, inflammation, and endoplasmic reticulum (ER) stress. By understanding the interplay of the cellular mechanisms involved, further strategies could be developed to prevent the reproductive abnormalities resulting from exposure to nicotine in utero and influence informed clinical guidelines for pregnant women. © 2015 Society for Reproduction and Fertility.

Complex cooperative breeders: Using infant care costs to explain variability in callitrichine social and reproductive behavior.

Science.gov (United States)

Díaz-Muñoz, Samuel L

2016-03-01

The influence of ecology on social behavior and mating strategies is one of the central questions in behavioral ecology and primatology. Callitrichines are New World primates that exhibit high behavioral variability, which is widely acknowledged, but not always systematically researched. Here, I examine the hypothesis that differences in the cost of infant care among genera help explain variation in reproductive traits. I present an integrative approach to generate and evaluate predictions from this hypothesis. I first identify callitrichine traits that vary minimally and traits that are more flexible (e.g., have greater variance or norm of reaction), including the number of males that mate with a breeding female, mechanisms of male reproductive competition, number of natal young retained, and the extent of female reproductive suppression. I outline how these more labile traits should vary along a continuum of infant care costs according to individual reproductive strategies. At one end of the spectrum, I predict that groups with higher infant care costs will show multiple adult males mating and providing infant care, high subordinate female reproductive suppression, few natal individuals delaying dispersal, and increased reproductive output by the dominant female -with opposite predictions under low infant costs. I derive an estimate of the differences in ecological and physiological infant care costs that suggest an order of ascending costs in the wild: Cebuella, Callithrix, Mico, Callimico, Saguinus, and Leontopithecus. I examine the literature on each genus for the most variable traits and evaluate a) where they fall along the continuum of infant care costs according to their reproductive strategies, and b) whether these costs correspond to the ecophysiological estimates of infant care costs. I conclude that infant care costs can provide a unifying explanation for the most variable reproductive traits among callitrichine genera. The approach presented can be

Breastfeeding and feminism: A focus on reproductive health, rights and justice

Science.gov (United States)

Labbok, Miriam H; Smith, Paige Hall; Taylor, Emily C

2008-01-01

The annual Breastfeeding and Feminism Symposia aim to reposition breastfeeding as a valued part of women's (re)productive lives and rights. The symposia are designed to raise the profile of breastfeeding within the women's advocacy and feminist studies' communities, and to increase recognition among breastfeeding supporters that breastfeeding promotion could receive more socio-political support by partnering with those concerned with women's reproductive health, rights and justice, women's economic advancement, and the elimination of social, economic and health inequities. The third symposium (2007) sought to build dialogue and increase communications between and among these diverse communities. The nine articles presented in this thematic series were selected by the journal editors, and represent the core discussions at the symposium. This editorial presents the areas of synergy and strategies for action that emerged from the discussions. These strategies and this thematic issue are intended to reassert the momentum that evolved among participants, and to stimulate involvement among individuals and organizations not in attendance in promoting breastfeeding as a women's reproductive health, rights and justice concern. PMID:18680575

Breastfeeding and feminism: a focus on reproductive health, rights and justice.

Science.gov (United States)

Labbok, Miriam H; Smith, Paige Hall; Taylor, Emily C

2008-08-04

The annual Breastfeeding and Feminism Symposia aim to reposition breastfeeding as a valued part of women's (re)productive lives and rights. The symposia are designed to raise the profile of breastfeeding within the women's advocacy and feminist studies' communities, and to increase recognition among breastfeeding supporters that breastfeeding promotion could receive more socio-political support by partnering with those concerned with women's reproductive health, rights and justice, women's economic advancement, and the elimination of social, economic and health inequities. The third symposium (2007) sought to build dialogue and increase communications between and among these diverse communities. The nine articles presented in this thematic series were selected by the journal editors, and represent the core discussions at the symposium. This editorial presents the areas of synergy and strategies for action that emerged from the discussions. These strategies and this thematic issue are intended to reassert the momentum that evolved among participants, and to stimulate involvement among individuals and organizations not in attendance in promoting breastfeeding as a women's reproductive health, rights and justice concern.

Elephant reproduction: improvement of breeding efficiency and development of a breeding strategy

NARCIS (Netherlands)

Thitaram, C.

2009-01-01

The efficiency of reproduction of the Asian elephant (Elephas maximus) has become of major concern. Captive breeding programs worldwide have met with limited success and few ex situ elephant populations are self-sustaining. The low birth rate and high mortality cause the captive population to

A Comparison of Methods and Results in Recruiting White and Black Women into Reproductive Studies: The MMC-PSU Cooperative Center on Reproduction Experience

Science.gov (United States)

Sweet, Stephanie; Legro, Richard S; Coney, PonJola

2008-01-01

Establishing a holistic approach for the enrollment of subjects into clinical trials that includes strategies for the recruitment of non-traditional and minority populations has been an elusive task. The existence of such a design, that is understood and embraced by investigators and the target communities, would streamline the current level of commitment of time, energy and resources. This is necessary to successfully encourage individual and community participation in research studies. The Center for Research in Reproduction at Meharry set out to recruit a large number of African American women volunteers of reproductive age into clinical trials. The experience, of recruiting volunteers from the African American community for clinical trials in the Meharry Medical College/Pennsylvania State University (MMC/PSU)'s Cooperative Center for Research in Reproduction at Meharry, is presented. PMID:18082470

Reproductive Health in the Framework of Cooperation for Development

Directory of Open Access Journals (Sweden)

Itziar Lozano

2000-12-01

Full Text Available The purpose of this paper is to review the way cooperation for development has dealt with sexual and reproductive rights by looking at the following three aspects of the question (with the case of Mexico as an example: the actors confronting one another over theissues under discussion (the international donor agencies and specifically the United Nations; the Vatican and the national churches; and the feminist movement; initiatives taking an empowerment approach; and a realistic, viable perspective on possible ways of establishing North-South cooperation relations.In relation to options on support and financing for reproductive rights projects, the resistance of cooperation agencies to incorporate the issue is analyzed. Then the paper discusses elements of a proposal for adoption of a global strategy, some possible pointsof departure, dilemmas faced by bodies receiving applications, and possible strategies for alliances between bodies in North and South.

Task-Driven Optimization of Fluence Field and Regularization for Model-Based Iterative Reconstruction in Computed Tomography.

Science.gov (United States)

Gang, Grace J; Siewerdsen, Jeffrey H; Stayman, J Webster

2017-12-01

This paper presents a joint optimization of dynamic fluence field modulation (FFM) and regularization in quadratic penalized-likelihood reconstruction that maximizes a task-based imaging performance metric. We adopted a task-driven imaging framework for prospective designs of the imaging parameters. A maxi-min objective function was adopted to maximize the minimum detectability index ( ) throughout the image. The optimization algorithm alternates between FFM (represented by low-dimensional basis functions) and local regularization (including the regularization strength and directional penalty weights). The task-driven approach was compared with three FFM strategies commonly proposed for FBP reconstruction (as well as a task-driven TCM strategy) for a discrimination task in an abdomen phantom. The task-driven FFM assigned more fluence to less attenuating anteroposterior views and yielded approximately constant fluence behind the object. The optimal regularization was almost uniform throughout image. Furthermore, the task-driven FFM strategy redistribute fluence across detector elements in order to prescribe more fluence to the more attenuating central region of the phantom. Compared with all strategies, the task-driven FFM strategy not only improved minimum by at least 17.8%, but yielded higher over a large area inside the object. The optimal FFM was highly dependent on the amount of regularization, indicating the importance of a joint optimization. Sample reconstructions of simulated data generally support the performance estimates based on computed . The improvements in detectability show the potential of the task-driven imaging framework to improve imaging performance at a fixed dose, or, equivalently, to provide a similar level of performance at reduced dose.

Sex-specific consequences of experimental cortisol elevation in pre-reproductive wild largemouth bass.

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O'Connor, Constance M; Nannini, Michael; Wahl, David H; Wilson, Samantha M; Gilmour, Kathleen M; Cooke, Steven J

2013-01-01

Experimental implants were used to investigate the effect of elevated cortisol (the primary stress hormone in teleost fish) on energetic and physiological condition prior to reproduction in male and female largemouth bass (Micropterus salmoides). Fish were wild-caught from lakes in Illinois, and held in experimental ponds for the duration of the study. Between 9 and 13 days after cortisol treatment, and immediately prior to the start of the reproductive period, treated and control animals were sampled. Females exhibited lower muscle lipid content, lower liver glycogen content, and higher hepatosomatic indices than males, regardless of treatment. Also, cortisol-treated females had higher hepatosomatic indices and lower final mass than control females, whereas males showed no differences between treatment groups. Finally, cortisol-treated females had higher gonadal cortisol concentrations than control females. In general, we found evidence of reduced energetic stores in female fish relative to male fish, likely due to timing differences in the allocation of resources during reproduction between males and females. Perhaps driven by the difference in energetic reserves, our data further suggest that females are more sensitive than males to elevated cortisol during the period immediately prior to reproduction. Copyright © 2012 Wiley Periodicals, Inc.

Male Reproductive Toxicology: Environmental Exposures vs Reproductive Competence

Science.gov (United States)

Like the lecture this chapter begins with an overview of male reproductive biology and transitions into male reproductive toxicology. It ends with a brief discussion of the strengths and weaknesses in male reproductive toxicology and epidemiology today. This chapter is highly il...

No effect of partner age and lifespan on female age-specific reproductive performance in blue tits

NARCIS (Netherlands)

Amininasab, Seyed Mehdi; Hammers, Martijn; Vedder, Oscar; Komdeur, Jan; Korsten, Peter

Studies of age-specific reproductive performance are fundamental to our understanding of population dynamics and the evolution of life-history strategies. In species with bi-parental care, reproductive ageing trajectories of either parent may be influenced by their partner's age, but this has rarely

No effect of partner age and lifespan on female age‐specific reproductive performance in blue tits

NARCIS (Netherlands)

Amininasab, Seyed Mehdi; Hammers, Martijn; Vedder, Oscar; Komdeur, Jan; Korsten, Peter

Studies of age-specific reproductive performance are fundamental to our understanding of population dynamics and the evolution of life-history strategies. In species with bi-parental care, reproductive ageing trajectories of either parent may be influenced by their partner's age, but this has rarely

Female reproductive disorders

DEFF Research Database (Denmark)

Crain, D Andrew; Janssen, Sarah J; Edwards, Thea M

2008-01-01

To evaluate the possible role of endocrine-disrupting compounds (EDCs) on female reproductive disorders emphasizing developmental plasticity and the complexity of endocrine-dependent ontogeny of reproductive organs. Declining conception rates and the high incidence of female reproductive disrupti......To evaluate the possible role of endocrine-disrupting compounds (EDCs) on female reproductive disorders emphasizing developmental plasticity and the complexity of endocrine-dependent ontogeny of reproductive organs. Declining conception rates and the high incidence of female reproductive...... disruptions warrant evaluation of the impact of EDCs on female reproductive health....

Importance of whole-plant biomass allocation and reproductive timing to habitat differentiation across the North American sunflowers.

Science.gov (United States)

Mason, Chase M; Goolsby, Eric W; Davis, Kaleigh E; Bullock, Devon V; Donovan, Lisa A

2017-05-01

Trait-based plant ecology attempts to use small numbers of functional traits to predict plant ecological strategies. However, a major gap exists between our understanding of organ-level ecophysiological traits and our understanding of whole-plant fitness and environmental adaptation. In this gap lie whole-plant organizational traits, including those that describe how plant biomass is allocated among organs and the timing of plant reproduction. This study explores the role of whole-plant organizational traits in adaptation to diverse environments in the context of life history, growth form and leaf economic strategy in a well-studied herbaceous system. A phylogenetic comparative approach was used in conjunction with common garden phenotyping to assess the evolution of biomass allocation and reproductive timing across 83 populations of 27 species of the diverse genus Helianthus (the sunflowers). Broad diversity exists among species in both relative biomass allocation and reproductive timing. Early reproduction is strongly associated with resource-acquisitive leaf economic strategy, while biomass allocation is less integrated with either reproductive timing or leaf economics. Both biomass allocation and reproductive timing are strongly related to source site environmental characteristics, including length of the growing season, temperature, precipitation and soil fertility. Herbaceous taxa can adapt to diverse environments in many ways, including modulation of phenology, plant architecture and organ-level ecophysiology. Although leaf economic strategy captures one key aspect of plant physiology, on their own leaf traits are not particularly predictive of ecological strategies in Helianthus outside of the context of growth form, life history and whole-plant organization. These results highlight the importance of including data on whole-plant organization alongside organ-level ecophysiological traits when attempting to bridge the gap between functional traits and plant

Assisted reproduction and distributive justice.

Science.gov (United States)

Panitch, Vida

2015-02-01

The Canadian province of Quebec recently amended its Health Insurance Act to cover the costs of In Vitro Fertilization (IVF). The province of Ontario recently de-insured IVF. Both provinces cited cost-effectiveness as their grounds, but the question as to whether a public health insurance system ought to cover IVF raises the deeper question of how we should understand reproduction at the social level, and whether its costs should be a matter of individual or collective responsibility. In this article I examine three strategies for justifying collective provisions in a liberal society and assess whether public reproductive assistance can be defended on any of these accounts. I begin by considering, and rejecting, rights-based and needs-based approaches. I go on to argue that instead we ought to address assisted reproduction from the perspective of the contractarian insurance-based model for public health coverage, according to which we select items for inclusion based on their unpredictability in nature and cost. I argue that infertility qualifies as an unpredictable incident against which rational agents would choose to insure under ideal conditions and that assisted reproduction is thereby a matter of collective responsibility, but only in cases of medical necessity or inability to pay. The policy I endorse by appeal to this approach is a means-tested system of coverage resembling neither Ontario nor Quebec's, and I conclude that it constitutes a promising alternative worthy of serious consideration by bioethicists, political philosophers, and policy-makers alike. © 2013 John Wiley & Sons Ltd.

"Clean, green and ethical" animal production. Case study: reproductive efficiency in small ruminants.

Science.gov (United States)

Martin, Graeme B; Kadokawa, Hiroya

2006-02-01

In response to changes in society and thus the marketplace, we need a vision for the future of our animal industries, including both on-farm and off-farm activities, that is "clean, green and ethical". Using small ruminants as a case study, we describe three "clean, green and ethical" strategies that farmers could use to improve reproductive performance. The first allows control of the timing of reproductive events by using socio-sexual signals (the "male effect") to induce synchronised ovulation in females. The second strategy, "focus feeding", is based on using short periods of nutritional supplements that are precisely timed and specifically designed for each event in the reproductive process (eg, gamete production, embryo survival, fetal programming, colostrum production). The third strategy aims to maximize offspring survival by a combination of management, nutrition and genetic selection for behaviour (temperament). All of these approaches involve non-pharmacological manipulation of the endogenous control systems of the animals and complement the detailed information from ultrasound that is now becoming available. Importantly, these approaches all have a solid foundation in reproductive biology. In several cases, they are currently used in commercial practice, but there is still room for improvement through both basic and applied research. Ultimately, these "clean, green and ethical" tools can be cost-effective, increase productivity and, at the same time, greatly improve the image of meat and milk industries in society and the marketplace.

Pollinator-driven ecological speciation in plants: new evidence and future perspectives.

Science.gov (United States)

Van der Niet, Timotheüs; Peakall, Rod; Johnson, Steven D

2014-01-01

The hypothesis that pollinators have been important drivers of angiosperm diversity dates back to Darwin, and remains an important research topic today. Mounting evidence indicates that pollinators have the potential to drive diversification at several different stages of the evolutionary process. Microevolutionary studies have provided evidence for pollinator-mediated floral adaptation, while macroevolutionary evidence supports a general pattern of pollinator-driven diversification of angiosperms. However, the overarching issue of whether, and how, shifts in pollination system drive plant speciation represents a critical gap in knowledge. Bridging this gap is crucial to fully understand whether pollinator-driven microevolution accounts for the observed macroevolutionary patterns. Testable predictions about pollinator-driven speciation can be derived from the theory of ecological speciation, according to which adaptation (microevolution) and speciation (macroevolution) are directly linked. This theory is a particularly suitable framework for evaluating evidence for the processes underlying shifts in pollination systems and their potential consequences for the evolution of reproductive isolation and speciation. This Viewpoint paper focuses on evidence for the four components of ecological speciation in the context of plant-pollinator interactions, namely (1) the role of pollinators as selective agents, (2) floral trait divergence, including the evolution of 'pollination ecotypes', (3) the geographical context of selection on floral traits, and (4) the role of pollinators in the evolution of reproductive isolation. This Viewpoint also serves as the introduction to a Special Issue on Pollinator-Driven Speciation in Plants. The 13 papers in this Special Issue range from microevolutionary studies of ecotypes to macroevolutionary studies of historical ecological shifts, and span a wide range of geographical areas and plant families. These studies further illustrate

Pollinator-driven ecological speciation in plants: new evidence and future perspectives

Science.gov (United States)

Van der Niet, Timotheüs; Peakall, Rod; Johnson, Steven D.

2014-01-01

Background The hypothesis that pollinators have been important drivers of angiosperm diversity dates back to Darwin, and remains an important research topic today. Mounting evidence indicates that pollinators have the potential to drive diversification at several different stages of the evolutionary process. Microevolutionary studies have provided evidence for pollinator-mediated floral adaptation, while macroevolutionary evidence supports a general pattern of pollinator-driven diversification of angiosperms. However, the overarching issue of whether, and how, shifts in pollination system drive plant speciation represents a critical gap in knowledge. Bridging this gap is crucial to fully understand whether pollinator-driven microevolution accounts for the observed macroevolutionary patterns. Testable predictions about pollinator-driven speciation can be derived from the theory of ecological speciation, according to which adaptation (microevolution) and speciation (macroevolution) are directly linked. This theory is a particularly suitable framework for evaluating evidence for the processes underlying shifts in pollination systems and their potential consequences for the evolution of reproductive isolation and speciation. Scope This Viewpoint paper focuses on evidence for the four components of ecological speciation in the context of plant-pollinator interactions, namely (1) the role of pollinators as selective agents, (2) floral trait divergence, including the evolution of ‘pollination ecotypes‘, (3) the geographical context of selection on floral traits, and (4) the role of pollinators in the evolution of reproductive isolation. This Viewpoint also serves as the introduction to a Special Issue on Pollinator-Driven Speciation in Plants. The 13 papers in this Special Issue range from microevolutionary studies of ecotypes to macroevolutionary studies of historical ecological shifts, and span a wide range of geographical areas and plant families. These studies

Reproductive Rights or Reproductive Justice? Lessons from Argentina.

Science.gov (United States)

Morgan, Lynn

2015-06-11

Argentine sexual and reproductive rights activists insist on using the language and framework of "human rights," even when many reproductive rights activists in the US and elsewhere now prefer the framework of "reproductive justice." Reflecting on conversations with Argentine feminist anthropologists, social scientists, and reproductive rights activists, this paper analyzes why the Argentine movement to legalize abortion relies on the contested concept of human rights. Its conclusion that "women's rights are human rights" is a powerful claim in post-dictatorship politics where abortion is not yet legal and the full scope of women's rights has yet to be included in the government's human rights agenda. Argentine feminist human rights activists have long been attentive to the ways that social class, gender, migration, and racism intersect with reproduction. Because their government respects and responds to a human rights framework, however, they have not felt it necessary--as U.S. feminists have--to invent a new notion of reproductive justice in order to be heard. Given the increasing popularity of reproductive justice in health and human rights, the Argentine case shows that rights-based claims can still be politically useful when a State values the concept of human rights. Copyright 2015 Morgan. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited.

Liability-driven investment in longevity risk management

OpenAIRE

Helena Aro; Teemu Pennanen

2013-01-01

This paper studies optimal investment from the point of view of an investor with longevity-linked liabilities. The relevant optimization problems rarely are analytically tractable, but we are able to show numerically that liability driven investment can significantly outperform common strategies that do not take the liabilities into account. In problems without liabilities the advantage disappears, which suggests that the superiority of the proposed strategies is indeed based on connections b...

Coordination of size-control, reproduction and generational memory in freshwater planarians

Science.gov (United States)

Yang, Xingbo; Kaj, Kelson J.; Schwab, David J.; Collins, Eva-Maria S.

2017-06-01

Uncovering the mechanisms that control size, growth, and division rates of organisms reproducing through binary division means understanding basic principles of their life cycle. Recent work has focused on how division rates are regulated in bacteria and yeast, but this question has not yet been addressed in more complex, multicellular organisms. We have, over the course of several years, assembled a unique large-scale data set on the growth and asexual reproduction of two freshwater planarian species, Dugesia japonica and Girardia tigrina, which reproduce by transverse fission and succeeding regeneration of head and tail pieces into new planarians. We show that generation-dependent memory effects in planarian reproduction need to be taken into account to accurately capture the experimental data. To achieve this, we developed a new additive model that mixes multiple size control strategies based on planarian size, growth, and time between divisions. Our model quantifies the proportions of each strategy in the mixed dynamics, revealing the ability of the two planarian species to utilize different strategies in a coordinated manner for size control. Additionally, we found that head and tail offspring of both species employ different mechanisms to monitor and trigger their reproduction cycles. Thus, we find a diversity of strategies not only between species but between heads and tails within species. Our additive model provides two advantages over existing 2D models that fit a multivariable splitting rate function to the data for size control: firstly, it can be fit to relatively small data sets and can thus be applied to systems where available data is limited. Secondly, it enables new biological insights because it explicitly shows the contributions of different size control strategies for each offspring type.

Not putting all their eggs in one basket: bet-hedging despite extraordinary annual reproductive output of desert tortoises

Science.gov (United States)

Lovich, Jeffrey E.; Ennen, Joshua R.; Yackulic, Charles B.; Meyer-Wilkins, Kathie; Agha, Mickey; Loughran, Caleb L.; Bjurlin, Curtis; Austin, Meaghan; Madrak, Sheila V.

2015-01-01

Bet-hedging theory makes the counter-intuitive prediction that, if juvenile survival is low and unpredictable, organisms should consistently reduce short-term reproductive output to minimize the risk of reproductive failure in the long-term. We investigated the long-term reproductive output of an Agassiz's desert tortoise (Gopherus agassizii) population and conformance to a bet-hedging strategy of reproduction in an unpredictable but comparatively productive environment. Most females reproduced every year, even during periods of low precipitation and poor germination of food plants, and the mean percentage of reproducing females did not differ significantly on an annual basis. Although mean annual egg production (clutch size × clutch frequency) differed significantly among years, mean clutch size and mean clutch frequency remained relatively constant. During an El Niño year, mean annual egg production and mean annual clutch frequency were the highest ever reported for this species. Annual egg production was positively influenced by maternal body size but clutch size and clutch frequency were not. Our long-term results confirm earlier conclusions based on short-term research that desert tortoises have a bet-hedging strategy of producing small clutches almost every year. The risk of long-term reproductive failure is minimized in unpredictable environments, both through time by annually producing multiple small clutches over a long reproductive lifespan, even in years of low resource availability, and through space by depositing multiple annual clutches in different locations. The extraordinary annual reproductive output of this population appears to be the result of a typically high but unpredictable biomass of annual food plants at the site relative to tortoise habitat in dryer regions. Under the comparatively productive but unpredictable conditions, tortoises conform to predictions of a bet-hedging strategy of reproduction with relatively small but consistent

Architectural Strategies for Enabling Data-Driven Science at Scale

Science.gov (United States)

Crichton, D. J.; Law, E. S.; Doyle, R. J.; Little, M. M.

2017-12-01

architectural strategies, including a 2015-2016 NASA AIST Study on Big Data, for evolving scientific research towards massively distributed data-driven discovery. It will include example use cases across earth science, planetary science, and other disciplines.

An experimental test for age-related improvements in reproductive performance in a frog that cares for its young

Science.gov (United States)

Dugas, Matthew B.; Moore, Michael P.; Wamelink, Caitlin N.; Richards-Zawacki, Corinne L.; Martin, Ryan A.

2015-10-01

Reproductive performance often increases with age in long-lived iteroparous organisms, a pattern that can result from within-individual increases in effort and/or competence. In free-living populations, it is typically difficult to distinguish these mechanisms or to isolate particular features of reproduction-influencing outcomes. In captive Oophaga pumilio, a frog in which mothers provide extended offspring provisioning via trophic eggs, we experimentally manipulated the age at which females started breeding and then monitored them across repeated reproductive events. This experiment allowed us to decouple age and experience and isolate maternal care as the proximate source of any differences in performance. Younger first-time mothers produced larger broods than older first-time mothers, but did not rear more offspring to independence. Across repeated reproductive events, maternal age was unassociated with any metric of performance. At later reproductive events, however, mothers produced fewer metamorphs, and a lower proportion of individuals in their broods reached independence. These patterns suggest that performance does not improve with age or breeding experience in this frog, and that eventual declines in performance are driven by reproductive activity, not age per se. Broadly, age-specific patterns of reproductive performance may depend on the proximate mechanism by which parents influence offspring fitness and how sensitive these are to effort and competence.

Timing reproduction in teleost fish: cues and mechanisms

Science.gov (United States)

Juntti, Scott A; Fernald, Russell D

2016-01-01

Fish comprise half of extant vertebrate species and use a rich variety of reproductive strategies that have yielded insights into the basic mechanisms that evolved for sex. To maximize the chances of fertilization and survival of offspring, fish species time reproduction to occur at optimal times. For years, ethologists have performed painstaking experiments to identify sensory inputs and behavioral outputs of the brain during mating. Here we review known mechanisms that generate sexual behavior, focusing on the factors that govern the timing of these displays. The development of new technologies, including high-throughput sequencing and genome engineering, have the potential to provide novel insights into how the vertebrate brain consummates mating at the appropriate time. PMID:26952366

Population genetic variation in the tree fern Alsophila spinulosa (Cyatheaceae): effects of reproductive strategy.

Science.gov (United States)

Wang, Ting; Su, Yingjuan; Li, Yuan

2012-01-01

Essentially all ferns can perform both sexual and asexual reproduction. Their populations represent suitable study objects to test the population genetic effects of different reproductive systems. Using the diploid homosporous fern Alsophila spinulosa as an example species, the main purpose of this study was to assess the relative impact of sexual and asexual reproduction on the level and structure of population genetic variation. Inter-simple sequence repeats analysis was conducted on 140 individuals collected from seven populations (HSG, LCH, BPC, MPG, GX, LD, and ZHG) in China. Seventy-four polymorphic bands discriminated a total of 127 multilocus genotypes. Character compatibility analysis revealed that 50.0 to 70.0% of the genotypes had to be deleted in order to obtain a tree-like structure in the data set from populations HSG, LCH, MPG, BPC, GX, and LD; and there was a gradual decrease of conflict in the data set when genotypes with the highest incompatibility counts were successively deleted. In contrast, in population ZHG, only 33.3% of genotypes had to be removed to achieve complete compatibility in the data set, which showed a sharp decline in incompatibility upon the deletion of those genotypes. All populations examined possessed similar levels of genetic variation. Population ZHG was not found to be more differentiated than the other populations. Sexual recombination is the predominant source of genetic variation in most of the examined populations of A. spinulosa. However, somatic mutation contributes most to the genetic variation in population ZHG. This change of the primary mode of reproduction does not cause a significant difference in the population genetic composition. Character compatibility analysis represents an effective approach to separate the role of sexual and asexual components in shaping the genetic pattern of fern populations.

Population genetic variation in the tree fern Alsophila spinulosa (Cyatheaceae: effects of reproductive strategy.

Directory of Open Access Journals (Sweden)

Ting Wang

Full Text Available BACKGROUND: Essentially all ferns can perform both sexual and asexual reproduction. Their populations represent suitable study objects to test the population genetic effects of different reproductive systems. Using the diploid homosporous fern Alsophila spinulosa as an example species, the main purpose of this study was to assess the relative impact of sexual and asexual reproduction on the level and structure of population genetic variation. METHODOLOGY/PRINCIPAL FINDINGS: Inter-simple sequence repeats analysis was conducted on 140 individuals collected from seven populations (HSG, LCH, BPC, MPG, GX, LD, and ZHG in China. Seventy-four polymorphic bands discriminated a total of 127 multilocus genotypes. Character compatibility analysis revealed that 50.0 to 70.0% of the genotypes had to be deleted in order to obtain a tree-like structure in the data set from populations HSG, LCH, MPG, BPC, GX, and LD; and there was a gradual decrease of conflict in the data set when genotypes with the highest incompatibility counts were successively deleted. In contrast, in population ZHG, only 33.3% of genotypes had to be removed to achieve complete compatibility in the data set, which showed a sharp decline in incompatibility upon the deletion of those genotypes. All populations examined possessed similar levels of genetic variation. Population ZHG was not found to be more differentiated than the other populations. CONCLUSIONS/SIGNIFICANCE: Sexual recombination is the predominant source of genetic variation in most of the examined populations of A. spinulosa. However, somatic mutation contributes most to the genetic variation in population ZHG. This change of the primary mode of reproduction does not cause a significant difference in the population genetic composition. Character compatibility analysis represents an effective approach to separate the role of sexual and asexual components in shaping the genetic pattern of fern populations.

Seasonal variation in male alternative reproductive tactics.

Science.gov (United States)

Monroe, M J; Amundsen, T; Utne-Palm, A C; Mobley, K B

2016-12-01

Genetic parentage analyses reveal considerable diversity in alternative reproductive behaviours (e.g. sneaking) in many taxa. However, little is known about whether these behaviours vary seasonally and between populations. Here, we investigate seasonal variation in male reproductive behaviours in a population of two-spotted gobies (Gobiusculus flavescens) in Norway. Male two-spotted gobies guard nests, attract females and care for fertilized eggs. We collected clutches and nest-guarding males early and late in the breeding season in artificial nests and used microsatellite markers to reconstruct parentage from a subset of offspring from each nest. We hypothesized that mating, reproductive success and sneaking should be more prevalent early in the breeding season when competition for mates among males is predicted to be higher. However, parentage analyses revealed similar values of mating, reproductive success and high frequencies of successful sneaking early (30% of nests) and late (27% of nests) in the season. We also found that multiple females with eggs in the same nest were fertilized by one or more sneaker males, indicating that some males in this population engage in a satellite strategy. We contrast our results to previous work that demonstrates low levels of cuckoldry in a population in Sweden. Our results demonstrate marked stability in both the genetic mating system and male alternative reproductive tactics over the breeding season. However, sneaking rates may vary geographically within a species, likely due to local selection influencing ecological factors encountered at different locations. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Reproductive Biology Including Evidence for Superfetation in the European Badger Meles meles (Carnivora: Mustelidae.

Directory of Open Access Journals (Sweden)

Leigh A L Corner

Full Text Available The reproductive biology of the European badger (Meles meles is of wide interest because it is one of the few mammal species that show delayed implantation and one of only five which are suggested to show superfetation as a reproductive strategy. This study aimed to describe the reproductive biology of female Irish badgers with a view to increasing our understanding of the process of delayed implantation and superfetation. We carried out a detailed histological examination of the reproductive tract of 264 female badgers taken from sites across 20 of the 26 counties in the Republic of Ireland. The key results show evidence of multiple blastocysts at different stages of development present simultaneously in the same female, supporting the view that superfetation is relatively common in this population of badgers. In addition we present strong evidence that the breeding rate in Irish badgers is limited by failure to conceive, rather than failure at any other stages of the breeding cycle. We show few effects of age on breeding success, suggesting no breeding suppression by adult females in this population. The study sheds new light on this unusual breeding strategy of delayed implantation and superfetation, and highlights a number of significant differences between the reproductive biology of female Irish badgers and those of Great Britain and Swedish populations.

Parentage of overlapping offspring of an arboreal-breeding frog with no nest defense: implications for nest site selection and reproductive strategy.

Science.gov (United States)

Tung, Wan-Ping; Chen, Yi-Huey; Cheng, Wei-Chun; Chuang, Ming-Feng; Hsu, Wan-Tso; Kam, Yeong-Choy; Lehtinen, Richard M

2015-01-01

Overlapping offspring occurs when eggs are laid in a nest containing offspring from earlier reproduction. Earlier studies showed that the parentage is not always obvious due to difficulties in field observation and/or alternative breeding tactics. To unveil the parentage between overlapping offspring and parents is critical in understanding oviposition site selection and the reproductive strategies of parents. Amplectant pairs of an arboreal-breeding frog, Kurixalus eiffingeri, lay eggs in tadpole-occupied nests where offspring of different life stages (embryos and tadpoles) coexist. We used five microsatellite DNA markers to assess the parentage between parents and overlapping offspring. We also tested the hypothesis that the male or female frog would breed in the same breeding site because of the scarcity of nest sites. Results showed varied parentage patterns, which may differ from the phenomenon of overlapping egg clutches reported earlier. Parentage analyses showed that only 58 and 25% of the tadpole-occupied stumps were reused by the same male and female respectively, partially confirming our prediction. Re-nesting by the same individual was more common in males than females, which is most likely related to the cost of tadpole feeding and/or feeding schemes of females. On the other hand, results of parentage analyses showed that about 42 and 75% of male and female respectively bred in tadpole-occupied stumps where tadpoles were genetically unrelated. Results of a nest-choice experiment revealed that 40% of frogs chose tadpole-occupied bamboo cups when we presented identical stumps, without or with tadpoles, suggesting that the habitat saturation hypothesis does not fully explain why frogs used the tadpole-occupied stumps. Several possible benefits of overlapping offspring with different life stages were proposed. Our study highlights the importance of integrating molecular data with field observations to better understand the reproductive biology and nest

Reproductive concessions between related and unrelated members promote eusociality in bees.

Science.gov (United States)

Andrade, Aline C R; Miranda, Elder A; Del Lama, Marco A; Nascimento, Fábio S

2016-05-23

Animal societies exhibit remarkable variation in their breeding strategies. Individuals can maximize their fitness by either reproducing or by helping relatives. Social hymenopterans have been key taxa for the study of Hamilton's inclusive fitness theory because the haplodiploid sex-determination system results in asymmetric relatedness among breeders producing conflict over the partitioning of reproduction. In small cooperative groups of insects, totipotent individuals may maximize their inclusive fitness by controlling reproduction despotically rather than helping their relatives. Here, we demonstrate that the dominant females of the primitively eusocial bee Euglossa melanotricha (Apidae: Euglossini) control reproduction, but concede part of the reproductive output with their related and unrelated subordinates. As expected, a dominant female capitalizes on the direct reproduction of related subordinates, according to her interests. We found that reproductive skew was positively correlated with relatedness. The concessions were highly reduced in mother-daughter and sibling nests (relatedness r ± s.d. = 0.54 ± 0.02 and 0.79 ± 0.02, respectively) but much more egalitarian in unrelated associations (r = -0.10 ± 0.01). We concluded that reproductive skew in these primitively eusocial bees is strongly related to the genetic structure of associations, and also that females are able to assess pairwise relatedness, either directly or indirectly, and use this information to mediate social contracts.

Female reproductive disorders

DEFF Research Database (Denmark)

Crain, D Andrew; Janssen, Sarah J; Edwards, Thea M

2008-01-01

To evaluate the possible role of endocrine-disrupting compounds (EDCs) on female reproductive disorders emphasizing developmental plasticity and the complexity of endocrine-dependent ontogeny of reproductive organs. Declining conception rates and the high incidence of female reproductive...... disruptions warrant evaluation of the impact of EDCs on female reproductive health....

Hurricane-Driven Patterns of Clonality in an Ecosystem Engineer: The Caribbean Coral Montastraea annularis

Science.gov (United States)

Foster, Nicola L.; Baums, Iliana B.; Sanchez, Juan A.; Paris, Claire B.; Chollett, Iliana; Agudelo, Claudia L.; Vermeij, Mark J. A.; Mumby, Peter J.

2013-01-01

K-selected species with low rates of sexual recruitment may utilise storage effects where low adult mortality allows a number of individuals to persist through time until a favourable recruitment period occurs. Alternative methods of recruitment may become increasingly important for such species if the availability of favourable conditions for sexual recruitment decline under rising anthropogenic disturbance and climate change. Here, we test the hypotheses that asexual dispersal is an integral life history strategy not only in branching corals, as previously reported, but also in a columnar, ‘K-selected’ coral species, and that its prevalence is driven by the frequency of severe hurricane disturbance. Montastraea annularis is a long-lived major frame-work builder of Caribbean coral reefs but its survival is threatened by the consequences of climate induced disturbance, such as bleaching, ocean acidification and increased prevalence of disease. 700 M. annularis samples from 18 reefs within the Caribbean were genotyped using six polymorphic microsatellite loci. We demonstrate that asexual reproduction occurs at varying frequency across the species-range and significantly contributes to the local abundance of M. annularis, with its contribution increasing in areas with greater hurricane frequency. We tested several competing hypotheses that might explain the observed pattern of genotypic diversity. 64% of the variation in genotypic diversity among the sites was explained by hurricane incidence and reef slope, demonstrating that large-scale disturbances combine with local habitat characteristics to shape the balance between sexual and asexual reproduction in populations of M. annularis. PMID:23308185

Hurricane-driven patterns of clonality in an ecosystem engineer: the Caribbean coral Montastraea annularis.

Directory of Open Access Journals (Sweden)

Nicola L Foster

Full Text Available K-selected species with low rates of sexual recruitment may utilise storage effects where low adult mortality allows a number of individuals to persist through time until a favourable recruitment period occurs. Alternative methods of recruitment may become increasingly important for such species if the availability of favourable conditions for sexual recruitment decline under rising anthropogenic disturbance and climate change. Here, we test the hypotheses that asexual dispersal is an integral life history strategy not only in branching corals, as previously reported, but also in a columnar, 'K-selected' coral species, and that its prevalence is driven by the frequency of severe hurricane disturbance. Montastraea annularis is a long-lived major frame-work builder of Caribbean coral reefs but its survival is threatened by the consequences of climate induced disturbance, such as bleaching, ocean acidification and increased prevalence of disease. 700 M. annularis samples from 18 reefs within the Caribbean were genotyped using six polymorphic microsatellite loci. We demonstrate that asexual reproduction occurs at varying frequency across the species-range and significantly contributes to the local abundance of M. annularis, with its contribution increasing in areas with greater hurricane frequency. We tested several competing hypotheses that might explain the observed pattern of genotypic diversity. 64% of the variation in genotypic diversity among the sites was explained by hurricane incidence and reef slope, demonstrating that large-scale disturbances combine with local habitat characteristics to shape the balance between sexual and asexual reproduction in populations of M. annularis.

Nutrient allocations and metabolism in two Collembola with contrasting reproduction and growth strategies

DEFF Research Database (Denmark)

Larsen, Thomas; Ventura, Marc; Damgaard, Christian

2009-01-01

1.  Physiological mechanisms such as allocation and release of nutrients are keys to understanding an animal's adaptation to a particular habitat. This study investigated how two detrivores with contrasting life-history traits allocated carbon (C) and nitrogen (N) to growth, reproduction and meta...

Prioritization of candidate genes for cattle reproductive traits, based on protein-protein interactions, gene expression, and text-mining

DEFF Research Database (Denmark)

Hulsegge, Ina; Woelders, Henri; Smits, Mari

2013-01-01

Reproduction is of significant economic importance in dairy cattle. Improved understanding of mechanisms that control estrous behavior and other reproduction traits could help in developing strategies to improve and/or monitor these traits. The objective of this study was to predict and rank gene...

Teaching reproductive options through the use of fiction: the Cider House Rules project.

Science.gov (United States)

Engstrom, Janet L; Hunter, Ramona G

2007-01-01

Alternative teaching strategies such as storytelling and the critical reading of literature are thought to help students develop their critical thinking, emotional intelligence, and cultural sensitivity and thereby better understand the context in which their patients live and make decisions. Such teaching methods are ideally suited for examining morally complex issues such as reproductive options. This article describes an alternative approach to teaching the complex personal, social, and moral issues surrounding the topic of reproductive options. The critical reading of the book, The Cider House Rules, provides a unique opportunity for students to obtain insight and understanding of the complex circumstances under which women and their families make reproductive decisions.

Studies on the reproductive efficiency of cattle using radioimmunoassay techniques

International Nuclear Information System (INIS)

1990-01-01

In 1982 the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, initiated a co-ordinated research programme with the aim of stimulating studies to characterize and improve the reproductive performance of indigenous cattle under the diverse environmental and management conditions prevailing in developing countries. This publication represents the results of the five year co-ordinated research programme, individual papers being essentially a synthesis of the work presented by the participants of the programme at the final research co-ordination meeting held in Vienna from 5 to 9 September 1988. Concurrently with the above mentioned research co-ordination meeting, the Joint FAO/IAEA Division held a consultants meeting on the interaction between reproduction, disease, nutrition and the environment, and on field reproductive management strategies. The papers presented by the consultants as well as their recommendations are included in this publication. These recommendations will form the basis of the future direction of livestock reproduction research programmes supported by the Joint FAO/IAEA Division. Refs, figs and tabs

CHALLENGES IN REPRODUCTIVE HEALTH CARE OF ADOLESCENTS IN SLOVENIA

Directory of Open Access Journals (Sweden)

Bojana Pinter

2018-02-01

Full Text Available Background: Slovenia is one of the most successful European countries in the prevention of adolescent pregnancy and the country with a relative early sexual engagement of adolescents. Every year new generations of adolescents are entering puberty, thus reproductive health care of adolescents should be our continuous priority. Methods: The most important challenges in reproductive health care of adolescents in Slovenia are early sexual engagement of adolescents, low double method use at sexual intercourse and inadequate detection of sexually transmitted infections. Possible responses should be found on a micro-level of physician (recognition of a new role of physician, promotion of ABC ap- proach and on a macro-level of society (development of national strategy of reproductive health care, introduction of systematic sexuality education in the schools. Conclusions: Challenges in reproductive health care of adolescents are several and possible responses are integral. A response on challenges demand that every physician recognizes his/her new role and develops his/her competency. Responses on challenges will be feasible with inter- connection of physicians with other physicians and professionals and with collaboration of profession and politics.

Redirecting reproductive immunology research toward pregnancy as a period of temporary immune tolerance.

Science.gov (United States)

Gleicher, Norbert; Kushnir, Vitaly A; Barad, David H

2017-04-01

Referring to two recent publications, we here propose that clinical reproductive immunology has for decades stagnated because reproductive medicine, including assisted reproduction (AR), has failed to accept embryo implantation as an immune system-driven process, dependent on establishment of maternal tolerance toward the implanting fetal semi-allograft (and complete allograft in cases of oocyte donation). Pregnancy represents a biologically unique period of temporary (to the period of gestation restricted) tolerance, otherwise only known in association with parasitic infections. Rather than investigating the immune pathways necessary to induce this rather unique state of tolerance toward the rapidly growing parasitic antigen load of the fetus, the field, instead, concentrated on irrelevant secondary immune phenomena (i.e., "immunological noise"). It, therefore, does not surprise that interesting recent research, offering new potential insights into maternal tolerance during pregnancy, was mostly published outside of the field of reproductive medicine. This research offers evidence for existence of inducible maternal tolerance pathways with the ability of improving maternal fecundity and, potentially, reducing such late pregnancy complications as premature labor and preeclampsia/eclampsia due to premature abatement of maternal tolerance. Increasing evidence also suggests that tolerance-inducing immune pathways are similar in successful pregnancy, successful organ transplantation and, likely also in the tolerance of "self" (i.e., prevention of autoimmunity). Identifying and isolating these pathways, therefore, may greatly benefit all three of these clinical areas, and research in reproductive immunology should be accordingly redirected.

Reproduction Symposium: developmental programming of reproductive and metabolic health.

Science.gov (United States)

Padmanabhan, V; Veiga-Lopez, A

2014-08-01

Inappropriate programming of the reproductive system by developmental exposure to excess steroid hormones is of concern. Sheep are well suited for investigating developmental origin of reproductive and metabolic disorders. The developmental time line of female sheep (approximately 5 mo gestation and approximately 7 mo to puberty) is ideal for conducting sequential studies of the progression of metabolic and/or reproductive disruption from the developmental insult to manifestation of adult consequences. Major benefits of using sheep include knowledge of established critical periods to target adult defects, a rich understanding of reproductive neuroendocrine regulation, availability of noninvasive approaches to monitor follicular dynamics, established surgical approaches to obtain hypophyseal portal blood for measurement of hypothalamic hormones, and the ability to perform studies in natural setting thereby keeping behavioral interactions intact. Of importance is the ability to chronically instrument fetus and mother for determining early endocrine perturbations. Prenatal exposure of the female to excess testosterone (T) leads to an array of adult reproductive disorders that include LH excess, functional hyperandrogenism, neuroendocrine defects, multifollicular ovarian morphology, and corpus luteum dysfunction culminating in early reproductive failure. At the neuroendocrine level, all 3 feedback systems are compromised. At the pituitary level, gonadotrope (LH secretion) sensitivity to GnRH is increased. Multifollicular ovarian morphology stems from persistence of follicles as well as enhanced follicular recruitment. These defects culminate in progressive loss of cyclicity and reduced fecundity. Prenatal T excess also leads to fetal growth retardation, an early marker of adult reproductive and metabolic diseases, insulin resistance, hypertension, and behavioral deficits. Collectively, the reproductive and metabolic deficits of prenatal T-treated sheep provide proof of

Alternative reproductive tactics in snail shell-brooding cichlids diverge in energy reserve allocation.

Science.gov (United States)

von Kuerthy, Corinna; Tschirren, Linda; Taborsky, Michael

2015-05-01

breeder strategy. Dwarf males did not accumulate long-term fat stores at all, which they can afford due to their small behavioral effort during reproduction and their continued feeding activity, conforming to an income breeder strategy. Our data confirm that the resource storage patterns of males pursuing ARTs can diverge substantially, which adds to our understanding of the coexistence and maintenance of alternative reproductive patterns within species.

Evaluation of alternative strategies to MERV 16-based air filtration systems for reduction of the risk of airborne spread of porcine reproductive and respiratory syndrome virus.

Science.gov (United States)

Dee, Scott; Pitkin, Andrea; Deen, John

2009-07-02

Porcine reproductive and respiratory syndrome (PRRS) is a re-emerging disease of pigs and a growing threat to the global swine industry. For sustainable disease control it is critical to prevent the airborne spread of the etiologic agent, PRRS virus, between pig populations. The application of MERV 16-based air filtration systems to swine facilities in an effort to reduce this risk has been proposed; however, due to the cost and air flow restrictions of such systems the need for alternative strategies has arisen. Therefore, the objective of this study was to evaluate 3 groups of alternative biosecurity strategies for reducing the risk of the airborne spread of PRRSV. Strategies evaluated included mechanical filters, antimicrobial filters and a disinfectant-EVAP (evaporative cooling) system. Results from this study indicate that while alternatives to MERV 16-based biosecurity protocols for protecting farms from the airborne spread of PRRSV are available, further information on their efficacy in the field is needed before conclusions can be drawn.

Data-Driven Iterative Vibration Signal Enhancement Strategy Using Alpha Stable Distribution

Directory of Open Access Journals (Sweden)

Grzegorz Żak

2017-01-01

Full Text Available The authors propose a novel procedure for enhancement of the signal to noise ratio in vibration data acquired from machines working in mining industry environment. Proposed method allows performing data-driven reduction of the deterministic, high energy, and low frequency components. Furthermore, it provides a way to enhance signal of interest. Procedure incorporates application of the time-frequency decomposition, α-stable distribution based signal modeling, and stability parameter in the time domain as a stoppage criterion for iterative part of the procedure. An advantage of the proposed algorithm is data-driven, automative detection of the informative frequency band as well as band with high energy due to the properties of the used distribution. Furthermore, there is no need to have knowledge regarding kinematics, speed, and so on. The proposed algorithm is applied towards real data acquired from the belt conveyor pulley drive’s gearbox.

Low participation rates amongst Asian women: implications for research in reproductive medicine.

Science.gov (United States)

Talaulikar, V S; Hussain, S; Perera, A; Manyonda, I T

2014-03-01

The last two decades have witnessed tremendous advances in the field of reproductive medicine, especially assisted reproductive technology and stem cell research. As research continues in future, it is vital to ensure that individuals from all ethnic backgrounds are represented in the study populations so that the findings of the research can be generalised for the benefit of all. Many studies, however, have noted a trend of low participation rates amongst Asian women in reproductive research. Inequalities in the ethnicity of research participants can be a source of substantial bias, and have major ethical and scientific ramifications. Several factors such as educational status, fear of wrong-doing, communication barriers, and socio-cultural beliefs have been suggested to play a role. There is a need for further exploration of the factors influencing Asian women's decision to accept or decline participation in reproductive research and for development of effective targeted strategies for research recruitment with the aim of encouraging research participation as well as donation of cryopreserved embryos or other reproductive tissues. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Customer-driven competition

Energy Technology Data Exchange (ETDEWEB)

Taylor, R. [Ontario Hydro, Toronto, ON (Canada)

1996-12-31

Ontario Hydro`s customer-driven strategy, recently approved by Hydro`s Executive Board, was described. The strategy is founded on the following components: (1) the dissolution of the Ontario power pool, i.e., the loss of Hydro`s franchise monopoly on generation, leaving only power transmission in the hands of the Corporation, (2) divestment of Ontario Hydro`s system operations and market operations functions to a new, independent Crown corporation called the Central Market Operator, (3) functional and organizational unbundling of Ontario Hydro into three signature businesses, Genco, Transco, and Retailco, and in the latter two, the functional unbundling of wires from sales and services, (4) a fully commercial Ontario Hydro with normal corporate powers, and (5) a corporate strategy for Ontario Hydro to grow in businesses in an open, symmetrical North American energy market. According to Ontario Hydro management this will allow competition and choice to all customers, have a disciplining effect on prices, and give rise to a retail market of new products and services, while at the same time preserve and enhance the value of public investment in the Corporation.

Customer-driven competition

International Nuclear Information System (INIS)

Taylor, R.

1996-01-01

Ontario Hydro's customer-driven strategy, recently approved by Hydro's Executive Board, was described. The strategy is founded on the following components: (1) the dissolution of the Ontario power pool, i.e., the loss of Hydro's franchise monopoly on generation, leaving only power transmission in the hands of the Corporation, (2) divestment of Ontario Hydro's system operations and market operations functions to a new, independent Crown corporation called the Central Market Operator, (3) functional and organizational unbundling of Ontario Hydro into three signature businesses, Genco, Transco, and Retailco, and in the latter two, the functional unbundling of wires from sales and services, (4) a fully commercial Ontario Hydro with normal corporate powers, and (5) a corporate strategy for Ontario Hydro to grow in businesses in an open, symmetrical North American energy market. According to Ontario Hydro management this will allow competition and choice to all customers, have a disciplining effect on prices, and give rise to a retail market of new products and services, while at the same time preserve and enhance the value of public investment in the Corporation

Environmental control of reproductive phenology and the effect of pollen supplementation on resource allocation in the cleistogamous weed, Ruellia nudiflora (Acanthaceae)

OpenAIRE

Munguía-Rosas, Miguel A.; Parra-Tabla, Victor; Ollerton, Jeff; Cervera, J. Carlos

2011-01-01

• Background and Aims Mixed reproductive strategies may have evolved as a response of plants to cope with environmental variation. One example of a mixed reproductive strategy is dimorphic cleistogamy, where a single plant produces closed, obligately self-pollinated (CL) flowers and open, potentially outcrossed (CH) flowers. Frequently, optimal environmental conditions favour production of more costly CH structures whilst economical and reliable CL structures are produced under less favourabl...

Relations among Individual Differences in Reproductive Strategies, Sexual Attractiveness, Affective and Punitive Intentions, and Imagined Sexual or Emotional Infidelity

Directory of Open Access Journals (Sweden)

Daniel N. Jones

2007-04-01

Full Text Available We examined relations among Mating Effort, Mate Value, Sex and individuals' self-reported responses to imagined sexual or emotional infidelity. We asked participants to describe the (1 upset or bother (2 aversive emotional reactions (3 punitive impulses, and (4 punitive intentions they experienced in response to imagined sexual or emotional infidelity. The results replicated previously documented sex differences in jealousy. In addition, imagined sexual infidelity upset individuals higher in Mating Effort more than those lower in Mating Effort. Higher Mating Effort also predicted greater temptation, intention, and likelihood to engage in punitive behaviors in response to imagined sexual or emotional infidelity. We discuss these data in light of individual differences in relations between reproductive strategy and romantic jealousy. Additionally, we point to the importance of controlling for co-linearity between reactions to sexual and emotional infidelity, and the need for addressing related methodological problems within jealousy research.

Flower color preferences of insects and livestock: effects on Gentiana lutea reproductive success.

Science.gov (United States)

Sobral, Mar; Losada, María; Veiga, Tania; Guitián, Javier; Guitián, José; Guitián, Pablo

2016-01-01

Angiosperms diversification was primarily driven by pollinator agents, but non-pollinator agents also promoted floral evolution. Gentiana lutea shows pollinator driven flower color variation in NW Spain. We test whether insect herbivores and livestock, which frequently feed in G.lutea, play a role in G. lutea flower color variation, by answering the following questions: (i) Do insect herbivores and grazing livestock show flower color preferences when feeding on G. lutea? (ii) Do mutualists (pollinators) and antagonists (seed predators, insect herbivores and livestock) jointly affect G. lutea reproductive success? Insect herbivores fed more often on yellow flowering individuals but they did not affect seed production, whereas livestock affected seed production but did not show clear color preferences. Our data indicate that flower color variation of G. lutea is not affected by insect herbivores or grazing livestock.

Optimal reproduction strategies in two species of mound-building termites.

Science.gov (United States)

Cameron, David A; Ivers, David J; Evans, Theodore A; Myerscough, Mary R

2008-01-01

We formulate a mathematical model for food collection and production of workers and nymphs in 2 species of mound building termites. We maximise the number of nymphs (reproductives) produced by each colony over its lifetime with respect to the proportion of eggs that hatch as nymphs as opposed to workers. The results predict that food storage has a very important influence on the pattern of nymph and worker production. Food storage affects the part of the year that nymph production dominates, whether nymphs and workers are produced at the same time or not, and the existence of a final phase in the colony's life when a very large number of nymphs but no workers are produced.

Role of lipids for the reproductive success of the Arctic copepod Calanus glacialis

Science.gov (United States)

Hatlebakk, M. K.; Graeve, M.; Niehoff, B.; Johnsen, G.; Søreide, J.

2016-02-01

Extensive energy storage is common among polar animals, and a range of reproductive strategies have evolved from pure capital breeders, relying on stored energy only, to 100% income breeders where freshly ingested food fuel reproduction. The Arctic calanoid copepod Calanus glacialis is primarily a grazer that accumulates large lipid stores during spring and summer. The breeding strategy to this relatively large and lipid-rich copepod is somewhere on the continuum from pure capital to 100% income breeder. To investigate the importance of stored lipids versus freshly ingested food for the reproductive success of this key copepod we conducted a combined laboratory and field study on a high-Arctic population of C. glacialis in Svalbard from January to May. Total lipids, lipid composition, gonad maturation, egg production and egg hatching success were carefully followed for starved and algal fed females in the laboratory and for females in situ. Lipid stores decreased significantly over time even when food was available, both in laboratory and in field, suggesting that the females largely depended on stored resources for reproduction no matter of the food availability. Lipid reduction was most rapid during gonad maturation prior to first egg production. Almost all fed females spawned compared to only half of the starved ones, and number of eggs and the egg hatching success were significantly improved for fed females. When food was scarce, females produced fewer but more lipid-rich eggs as opposed to more eggs with less lipids when food was abundant - a strategy not previously described for C. glacialis. The fatty acid composition appeared to be more important than the total lipid content for ensuring high egg hatching success, and the polyunsaturated fatty acids 20:5(n-3) and 22:6(n-3), as well as the saturated fatty acids 16:0 and 18:0 seemed to be particularly important. We conclude that C. glacialis is capable of capital breeding, but primarily rely on fresh food for

Spatial and temporal dynamics of corticosterone and corticosterone binding globulin are driven by environmental heterogeneity.

Science.gov (United States)

Shultz, Michael Todd; Kitaysky, Alexander Stanislav

2008-02-01

The question of whether changes in glucocorticoid concentrations reflect consistent changes in physiology associated with transitions between different stages of reproduction, or whether they reflect responses to environmental conditions, is one the central issues in field endocrinology studies. We examined the temporal and spatial dynamics of corticosterone (CORT, baseline, and acute stress-induced) and corticosterone binding globulin (CBG) concentrations in blood of Black-legged Kittiwakes (Rissa tridactyla) breeding at four major colonies in the Bering Sea, Alaska, during 1999-2005. We found that total CORT, free CORT, and CBG capacity varied inconsistently among reproductive stages, colonies, and years. Total CORT levels were positively correlated with CBG capacity. Variation in free CORT was largely driven by variation in total CORT. Results suggest that the adrenocortical function and CBG in breeding kittiwakes do not vary as a consequence of stage-specific modulation associated with a particular reproductive stage as in some short-lived passerine birds. Rather, in accord with predictions for a long-lived species, the lack of consistent colony, year, and reproductive stage patterns in baseline and maximum CORT, and CBG indicates that environmental factors, probably local dynamics of food availability, drive variation in these factors.

Specific recognition of reproductive parasite workers by nest-entrance guards in the bumble bee Bombus terrestris.

Science.gov (United States)

Blacher, Pierre; Boreggio, Laurie; Leroy, Chloé; Devienne, Paul; Châline, Nicolas; Chameron, Stéphane

2013-12-10

The impact of social parasites on their hosts' fitness is a strong selective pressure that can lead to the evolution of adapted defence strategies. Guarding the nest to prevent the intrusion of parasites is a widespread response of host species. If absolute rejection of strangers provides the best protection against parasites, more fine-tuned strategies can prove more adaptive. Guarding is indeed costly and not all strangers constitute a real threat. That is particularly true for worker reproductive parasitism in social insects since only a fraction of non-nestmate visitors, the fertile ones, can readily engage in parasitic reproduction. Guards should thus be more restrictive towards fertile than sterile non-nestmate workers. We here tested this hypothesis by examining the reaction of nest-entrance guards towards nestmate and non-nestmate workers with varying fertility levels in the bumble bee Bombus terrestris. Because social recognition in social insects mainly relies on cuticular lipids (CLs), chemical analysis was also conducted to examine whether workers' CLs could convey the relevant information upon which guards could base their decision. We thus aimed to determine whether an adapted defensive strategy to worker reproductive parasitism has evolved in B. terrestris colonies. Chemical analysis revealed that the cuticular chemical profiles of workers encode information about both their colony membership and their current fertility, therefore providing potential recognition cues for a suitable adjustment of the guards' defensive decisions. We found that guards were similarly tolerant towards sterile non-nestmate workers than towards nestmate workers. However, as predicted, guards responded more aggressively towards fertile non-nestmates. Our results show that B. terrestris guards discriminate non-nestmates that differ in their reproductive potential and respond more strongly to the individuals that are a greatest threat for the colony. Cuticular hydrocarbons are

Developing a theory driven text messaging intervention for addiction care with user driven content.

Science.gov (United States)

Muench, Frederick; Weiss, Rebecca A; Kuerbis, Alexis; Morgenstern, Jon

2013-03-01

The number of text messaging interventions designed to initiate and support behavioral health changes have been steadily increasing over the past 5 years. Messaging interventions can be tailored and adapted to an individual's needs in their natural environment-fostering just-in-time therapies and making them a logical intervention for addiction continuing care. This study assessed the acceptability of using text messaging for substance abuse continuing care and the intervention preferences of individuals in substance abuse treatment in order to develop an interactive mobile text messaging intervention. Fifty individuals enrolled in intensive outpatient substance abuse treatment completed an assessment battery relating to preferred logistics of mobile interventions, behavior change strategies, and types of messages they thought would be most helpful to them at different time points. Results indicated that 98% participants were potentially interested in using text messaging as a continuing care strategy. Participants wrote different types of messages that they perceived might be most helpful, based on various hypothetical situations often encountered during the recovery process. Although individuals tended to prefer benefit driven over consequence driven messages, differences in the perceived benefits of change among individuals predicted message preference. Implications for the development of mobile messaging interventions for the addictions are discussed. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Reproductive toxicity: Male and female reproductive systems as targets for chemical injury

Energy Technology Data Exchange (ETDEWEB)

Mattison, D.R.; Plowchalk, D.R.; Meadows, M.J.; Al-Juburi, A.Z.; Gandy, J.; Malek, A. (Univ. of Arkansas for Medical Sciences, Little Rock (USA))

1990-03-01

On the basis of current knowledge of reproductive biology and toxicology, it is apparent that chemicals affecting reproduction may elicit their effects at a number of sites in both the male and the female reproductive system. This multiplicity of targets is attributable to the dynamic nature of the reproductive system, in which the hypothalamic-pituitary-gonadal axis is controlled by precise positive and negative feedback mechanisms among its components. Interference by a xenobiotic at any level in either the male or the female reproductive system may ultimately impair hypothalamic or pituitary function. Normal gonadal processes such as spermatogenesis or oogenesis, ejaculation or ovulation, hormone production by Leydig or granulosa cells, and the structure or function of the accessory reproductive structures (e.g., epididymis, fallopian tube) also appear vulnerable to xenobiotics. The reproductive system is a complex one that requires local and circulating hormones for control. This brief review illustrates a system for characterizing the mechanism of action of reproductive toxicants, as well as for defining the sites available for disruption of reproduction. Unfortunately, at present, data addressing the actual vulnerability of reproduction are sorely lacking. However, when experiments have been conducted and combined with epidemiologic data or clinical observation, it has been possible to demonstrate impairment of reproductive processes by xenobiotics. The role of environmental exposure to xenobiotics in the increase in infertility that has been observed remains to be defined. 87 references.

Developmental theory-driven evaluation: Strategies for course ...

African Journals Online (AJOL)

This article focuses on the longitudinal evaluative strategies used in the development of a new teaching approach for a university course with high failure rates. The subject is compulsory for all first year engineering students at our university. The evaluation has been conducted as part of a process of developmental action ...

Male Reproductive System

Science.gov (United States)

... With the Male Reproductive System Print en español Sistema reproductor masculino Reproduction All living things reproduce. Reproduction — ... of Use Notice of Nondiscrimination Visit the Nemours Web site. Note: All information on KidsHealth® is for ...

Life history strategy of the honey bee, Apis mellifera.

Science.gov (United States)

Seeley, Thomas D

1978-01-01

The feral honey bee queens (colonies) of central New York State (USA) show a K-type life history strategy. Their demographic characteristics include low early life mortality, low reproductive rate, long lifespan, high population stability and repeated reproductions. Identifying the life history strategy of these bees reveals the general pattern of selection for competitive ability, rather than productivity, which has shaped their societies. Selection for competitive power explains the adaptiveness (compared with alternatives found in many other insect societies) of the large perennial colonies, infrequent but expensive offspring, and efficient foraging which characterize the social organization of these bees.

Variation in habitat choice and delayed reproduction: Adaptive queuing strategies or individual quality differences?

NARCIS (Netherlands)

Van de Pol, M.; Pen, I.; Heg, D.; Weissing, F.J.

2007-01-01

In most species, some individuals delay reproduction or occupy inferior breeding positions. The queue hypothesis tries to explain both patterns by proposing that individuals strategically delay breeding (queue) to acquire better breeding or social positions. In 1995, Ens, Weissing, and Drent

Anopheline Reproductive Biology: Impacts on Vectorial Capacity and Potential Avenues for Malaria Control.

Science.gov (United States)

Mitchell, Sara N; Catteruccia, Flaminia

2017-12-01

Vectorial capacity is a mathematical approximation of the efficiency of vector-borne disease transmission, measured as the number of new infections disseminated per case per day by an insect vector. Multiple elements of mosquito biology govern their vectorial capacity, including survival, population densities, feeding preferences, and vector competence. Intriguingly, biological pathways essential to mosquito reproductive fitness directly or indirectly influence a number of these elements. Here, we explore this complex interaction, focusing on how the interplay between mating and blood feeding in female Anopheles not only shapes their reproductive success but also influences their ability to sustain Plasmodium parasite development. Central to malaria transmission, mosquito reproductive biology has recently become the focus of research strategies aimed at malaria control, and we discuss promising new methods based on the manipulation of key reproductive steps. In light of widespread resistance to all public health-approved insecticides targeting mosquito reproduction may prove crucial to the success of malaria-eradication campaigns. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

Characterizing the reproduction number of epidemics with early subexponential growth dynamics.

Science.gov (United States)

Chowell, Gerardo; Viboud, Cécile; Simonsen, Lone; Moghadas, Seyed M

2016-10-01

generalized-growth concept also provides us a compelling argument for the unexpected extinction of certain emerging disease outbreaks during the early ascending phase. Overall, our approach promotes a more reliable and data-driven characterization of the early epidemic phase, which is important for accurate estimation of the reproduction number and prediction of disease impact. © 2016 The Author(s).

Characterizing the reproduction number of epidemics with early subexponential growth dynamics

Science.gov (United States)

Viboud, Cécile; Simonsen, Lone; Moghadas, Seyed M.

2016-01-01

generalized-growth concept also provides us a compelling argument for the unexpected extinction of certain emerging disease outbreaks during the early ascending phase. Overall, our approach promotes a more reliable and data-driven characterization of the early epidemic phase, which is important for accurate estimation of the reproduction number and prediction of disease impact. PMID:27707909

Size does matter: adolescent build and male reproductive success in the Guangzhou Biobank Cohort Study.

Science.gov (United States)

Schooling, C Mary; Jiang, Chaoqiang; Zhang, Weisen; Lam, Tai Hing; Cheng, Kar Keung; Leung, Gabriel M

2011-01-01

Women usually report attributes of masculinity as attractive. These are attributes are metabolically expensive. We examined the trade off of a key attribute of masculinity, muscularity, proxied by recalled adolescence build, with lifetime reproductive success in the developing country setting of Southern China. We used poisson multivariable regression in 19,168 older (≥ 50 years) Chinese from the Guangzhou Biobank Cohort Study (phases 2 and 3) to examine the sex-stratified, adjusted associations of recalled adolescent relative weight (light (n = 6730), average (n = 9344), and heavy (n = 3094)) with number of offspring. Among men, recalled heavy adolescent weight compared with light was associated with an incident rate ratio for offspring of 1.08 (95% confidence interval [CI] 1.04-1.13) adjusted for age. This estimate was unchanged by adjustment for life course socio-economic position. There was no such association in women. Male physical attractiveness, possibly representing levels of testosterone, was rewarded by lifetime reproductive success, despite potential costs. Socio-economic development may facilitate an inevitable move toward environmentally driven higher levels of testosterone with corresponding public health implications for any conditions or societal attributes driven by testosterone. Further investigation is warranted. Copyright © 2011 Elsevier Inc. All rights reserved.

Decisional strategy determines whether frame influences treatment preferences for medical decisions.

Science.gov (United States)

Woodhead, Erin L; Lynch, Elizabeth B; Edelstein, Barry A

2011-06-01

Decision makers are influenced by the frame of information such that preferences vary depending on whether survival or mortality data are presented. Research is inconsistent as to whether and how age impacts framing effects. This paper presents two studies that used qualitative analyses of think-aloud protocols to understand how the type of information used in the decision making process varies by frame and age. In Study 1, 40 older adults, age 65 to 89, and 40 younger adults, age 18 to 24, responded to a hypothetical lung cancer scenario in a within-subject design. Participants received both a survival and mortality frame. Qualitative analyses revealed that two main decisional strategies were used by all participants: one strategy reflected a data-driven decisional process, whereas the other reflected an experience-driven process. Age predicted decisional strategy, with older adults less likely to use a data-driven strategy. Frame interacted with strategy to predict treatment choice; only those using a data-driven strategy demonstrated framing effects. In Study 2, 61 older adults, age 65 to 98, and 63 younger adults, age 18 to 30, responded to the same scenarios as in Study 1 in a between-subject design. The results of Study 1 were replicated, with age significantly predicting decisional strategy and frame interacting with strategy to predict treatment choice. Findings suggest that framing effects may be more related to decisional strategy than to age. (c) 2011 APA, all rights reserved.

The reproductive effort of Lepeophtheirus pectoralis (Copepoda: Caligidae): insights into the egg production strategy of parasitic copepods.

Science.gov (United States)

Frade, D G; Santos, M J; Cavaleiro, F I

2016-01-01

The reproductive effort of Lepeophtheirus pectoralis (Müller O. F., 1776), a caligid copepod, which is commonly found infecting the European flounder, Platichthys flesus (Linnaeus, 1758), is studied in detail for the first time. Seasonal variation in body dimensions and reproductive effort are analysed. Data for 120 ovigerous females, 30 from each season of the year, were considered in the analyses. Females were larger and produced a larger number of smaller eggs in winter, than during the summer. The relationship between egg number and egg size is similar to that recorded for other copepods exploiting fish hosts. Much of the recorded variation was also similar to that reported for a copepod parasitic on an invertebrate host, which suggests the possibility of a general trend in copepod reproduction. Overall, our results provide further support for the hypothesis that there is an alternation of summer and winter generations.

Reproductive tourism and the quest for global gender justice.

Science.gov (United States)

Donchin, Anne

2010-09-01

Reproductive tourism is a manifestation of a larger, more inclusive trend toward globalization of capitalist cultural and material economies. This paper discusses the development of cross-border assisted reproduction within the globalized economy, transnational and local structural processes that influence the trade, social relations intersecting it, and implications for the healthcare systems affected. I focus on prevailing gender structures embedded in the cross-border trade and their intersection with other social and economic structures that reflect and impact globalization. I apply a social connection model of responsibility for unjust outcomes and consider strategies to counter structural injustices embedded in this industry. The concluding section discusses policy reforms and proposals for collaborative action to preclude further injustices and extend full human rights to all.

Infertility in reproductive-age female cancer survivors.

Science.gov (United States)

Levine, Jennifer M; Kelvin, Joanne Frankel; Quinn, Gwendolyn P; Gracia, Clarisa R

2015-05-15

Improved survival rates among reproductive-age females diagnosed with cancer have increased the focus on long-term quality of life, including maintenance of the ability to conceive biological children. Cancer-directed therapies such as high-dose alkylating agents and radiation to the pelvis, which deplete ovarian reserve, radiation to the brain, which affects the hypothalamic-pituitary-gonadal axis, and surgical resection of reproductive structures can decrease the likelihood of having biological children. Standard fertility preservation strategies such as embryo and oocyte cryopreservation before the onset of therapy offer the opportunity to conserve fertility, but they may not be feasible because of the urgency to start cancer therapy, financial limitations, and a lack of access to reproductive endocrinologists. Ovarian tissue freezing is considered experimental, with limited data related to pregnancies, but it minimizes treatment delay. Studies evaluating gonadotropin-releasing hormone analogues have had mixed results, although a recent randomized, prospective study in women with breast cancer demonstrated a protective effect. Fertility preservation programs are increasingly being developed within cancer programs. In this article, we describe risks to infertility and options for preservation, raise psychosocial and ethical issues, and propose elements for establishing an effective fertility preservation program. © 2015 American Cancer Society.

Reproductive Disorders in Snakes.

Science.gov (United States)

Di Girolamo, Nicola; Selleri, Paolo

2017-05-01

Reproduction of snakes is one of the challenging aspects of herpetology medicine. Due to the complexity of reproduction, several disorders may present before, during, or after this process. This article describes the physical examination, and radiographic, ultrasonographic, and endoscopic findings associated with reproductive disorders in snakes. Surgical techniques used to resolve reproductive disorders in snakes are described. Finally, common reproductive disorders in snakes are individually discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

Reproductive dormancy in boll-weevil from populations of the midwest of Brazil.

Science.gov (United States)

Paula, D P; Claudino, D; Timbó, R V; Miranda, J E; Bemquerer, M P; Ribeiro, A C J; Sujii, E R; Fontes, E M G; Pires, C S S

2013-02-01

The boll weevil (Anthonomus grandis Boheman) (Coleoptera: Curculionidae) is an introduced pest in Brazil, which in 30 yr has successfully expanded to various eco-regions and became the most important pest of cotton (Gossypium hirsutum, Malvaceae). Given the limited knowledge about the adaptive mechanisms that allowed successful establishment of the pest population in a tropical region, in this work we studied the potential of the Midwest population of boll weevils to enter a reproductive dormancy and identified the importance of the feeding source for induction of dormancy. We investigated morphological and physiological characters as indicators of the dormancy. We also investigated the occurrence of reproductive dormancy in boll weevils populations from cotton farms of the Midwestern region of Brazil during the cotton and noncotton seasons of 2009 and 2010. The studies revealed that boll weevils entered facultative reproductive dormancy; however, unlike what has been observed for boll weevils from temperate and subtropical regions, the hypertrophy of fat body and hexamerin levels did not straightly correlated to reproductive dormancy. The food source and field conditions during early adult development were decisive factor for the induction of reproductive dormancy. The incidence of reproductive dormancy increased progressively as the phenology of cotton plant advanced, reaching approximately 90% at the end of the crop season. During the noncotton season, the boll weevil was predominantly found in reproductive dormancy, especially females; however, there is evidence of use of multiple adaptive strategies to colonize the next harvest.

Flower color preferences of insects and livestock: effects on Gentiana lutea reproductive success

Science.gov (United States)

Losada, María; Veiga, Tania; Guitián, Javier; Guitián, José; Guitián, Pablo

2016-01-01

Angiosperms diversification was primarily driven by pollinator agents, but non-pollinator agents also promoted floral evolution. Gentiana lutea shows pollinator driven flower color variation in NW Spain. We test whether insect herbivores and livestock, which frequently feed in G.lutea, play a role in G. lutea flower color variation, by answering the following questions: (i) Do insect herbivores and grazing livestock show flower color preferences when feeding on G. lutea? (ii) Do mutualists (pollinators) and antagonists (seed predators, insect herbivores and livestock) jointly affect G. lutea reproductive success? Insect herbivores fed more often on yellow flowering individuals but they did not affect seed production, whereas livestock affected seed production but did not show clear color preferences. Our data indicate that flower color variation of G. lutea is not affected by insect herbivores or grazing livestock. PMID:27014509

Flower color preferences of insects and livestock: effects on Gentiana lutea reproductive success

Directory of Open Access Journals (Sweden)

Mar Sobral

2016-03-01

Full Text Available Angiosperms diversification was primarily driven by pollinator agents, but non-pollinator agents also promoted floral evolution. Gentiana lutea shows pollinator driven flower color variation in NW Spain. We test whether insect herbivores and livestock, which frequently feed in G.lutea, play a role in G. lutea flower color variation, by answering the following questions: (i Do insect herbivores and grazing livestock show flower color preferences when feeding on G. lutea? (ii Do mutualists (pollinators and antagonists (seed predators, insect herbivores and livestock jointly affect G. lutea reproductive success? Insect herbivores fed more often on yellow flowering individuals but they did not affect seed production, whereas livestock affected seed production but did not show clear color preferences. Our data indicate that flower color variation of G. lutea is not affected by insect herbivores or grazing livestock.

Congenital anomalies after assisted reproductive technology

DEFF Research Database (Denmark)

Pinborg, Anja; Henningsen, Anna-Karina Aaris; Malchau, Sara Sofie

2013-01-01

Worldwide, more than 5 million children have been born after assisted reproductive technology (ART), and in many developed countries ART infants represent more than 1% of the birth cohorts. It is well known that ART children are at increased risk of congenital malformations even after adjustment...... for known confounders such as maternal age. The proportion of ART children is not negligible, and knowledge about the causes of the higher risk of congenital malformations is crucial to develop prevention strategies to reduce the future risk in ART children. The aim of this review is to summarize...

An Application of Multivariate Statistical Analysis for Query-Driven Visualization

Energy Technology Data Exchange (ETDEWEB)

Gosink, Luke J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Garth, Christoph [Univ. of California, Davis, CA (United States); Anderson, John C. [Univ. of California, Davis, CA (United States); Bethel, E. Wes [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Joy, Kenneth I. [Univ. of California, Davis, CA (United States)

2011-03-01

Driven by the ability to generate ever-larger, increasingly complex data, there is an urgent need in the scientific community for scalable analysis methods that can rapidly identify salient trends in scientific data. Query-Driven Visualization (QDV) strategies are among the small subset of techniques that can address both large and highly complex datasets. This paper extends the utility of QDV strategies with a statistics-based framework that integrates non-parametric distribution estimation techniques with a new segmentation strategy to visually identify statistically significant trends and features within the solution space of a query. In this framework, query distribution estimates help users to interactively explore their query's solution and visually identify the regions where the combined behavior of constrained variables is most important, statistically, to their inquiry. Our new segmentation strategy extends the distribution estimation analysis by visually conveying the individual importance of each variable to these regions of high statistical significance. We demonstrate the analysis benefits these two strategies provide and show how they may be used to facilitate the refinement of constraints over variables expressed in a user's query. We apply our method to datasets from two different scientific domains to demonstrate its broad applicability.

Strategies for the prevention and treatment of reproductive tract infections among women in Vietnam

DEFF Research Database (Denmark)

Huong, Nguyen My; Gammeltoft, Tine; Rasch, Vibeke

2008-01-01

This paper presents selected findings from a larger study on reproductive tract infections (RTIs) among women seeking abortion in Northern Vietnam. In particular it focuses on women's experience of RTIs within the context of their perceptions of female physiology and what women do to prevent and ...

THE FATTY ACIDS OF DIET AFFECT THE REPRODUCTIVE PHYSIOLOGY IN BOVINE FEMALE: A REVIEW

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José Luis Espinoza Villavicencio

2012-03-01

Full Text Available Reproduction is the basis of bovine meat and milk production: As a direct result of reproduction, the cycles of calf and milk production are renewed. However, there are many limiting steps in this process as: low pregnancy rates and long open days that result in increasing parturition intervals. Reproductive efficiency in dairy and beef cattle is multifactorial. Nutrition is one of the most important factors affecting this efficiency, and some results have shown that feeding diverse sources of lipids and specifically, fatty acids (FA can result in a better reproductive efficiency. As a nutrition strategy to improve reproductive efficiency, FA of the omega 3 (n-3 and omega 6 (n-6 families have been studied, and it has been shown that these FA can control follicular development, production of progesterone in the corpus luteum, and secretion of PGF2α from the endometrium, increasing embryonic survival and pregnancy rates. The purpose of this revision is to analyze the possible mechanisms by which FA in the diet improve reproductive efficiency of cows, with especial emphasis on FA n-3 and n-6.

A cross sectional study on reproductive health disorders in dairy cattle in Sudan

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Amira Mohamed Elhassan

2015-06-01

Full Text Available A cross sectional survey was carried out in dairy farms in four States of Sudan to determine prevalence of reproductive health disorders that affect dairy cattle industries in the country. A total of 575 adult female cows in dairy farms located in Khartoum, Gezira, Sennar, and White Nile States were investigated using questionnaire survey and face-to-face interviews with the owners. The results indicated that 24.4% of the animals were affected with one or more reproductive health disorders. Abortion (57.1% represented the major health problem affecting calf yield, followed by infertility (34.3% and neonatal death (8.6%. Other health problems included stillbirth, vaginitis and retained placenta, anomalies, metritis and repeat breeder. Most of the abortion cases were detected during third trimester (76.25% followed by first (12.5% and second (11.25% trimesters. Finally, countrywide investigations of reproductive disorders and increasing awareness to the owners are recommended for designing successful control strategies of reproductive disorders in Sudan.

Maximum power extraction under different vector-control schemes and grid-synchronization strategy of a wind-driven Brushless Doubly-Fed Reluctance Generator.

Science.gov (United States)

Mousa, Mohamed G; Allam, S M; Rashad, Essam M

2018-01-01

This paper proposes an advanced strategy to synchronize the wind-driven Brushless Doubly-Fed Reluctance Generator (BDFRG) to the grid-side terminals. The proposed strategy depends mainly upon determining the electrical angle of the grid voltage, θ v and using the same transformation matrix of both the power winding and grid sides to ensure that the generated power-winding voltage has the same phase-sequence of the grid-side voltage. On the other hand, the paper proposes a vector-control (power-winding flux orientation) technique for maximum wind-power extraction under two schemes summarized as; unity power-factor operation and minimum converter-current. Moreover, a soft-starting method is suggested to avoid the employed converter over-current. The first control scheme is achieved by adjusting the command power-winding reactive power at zero for a unity power-factor operation. However, the second scheme depends on setting the command d-axis control-winding current at zero to maximize the ratio of the generator electromagnetic-torque per the converter current. This enables the system to get a certain command torque under minimum converter current. A sample of the obtained simulation and experimental results is presented to check the effectiveness of the proposed control strategies. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

A practice-driven systematic review of dependency analysis solutions

NARCIS (Netherlands)

Callo Arias, Trosky B.; Spek, Pieter van der; Avgeriou, Paris

2011-01-01

When following architecture-driven strategies to develop large software-intensive systems, the analysis of the dependencies is not an easy task. In this paper, we report a systematic literature review on dependency analysis solutions. Dependency analysis concerns making dependencies due to

Individual heterogeneity and offspring sex affect the growth-reproduction trade-off in a mammal with indeterminate growth.

Science.gov (United States)

Gélin, Uriel; Wilson, Michelle E; Cripps, Jemma; Coulson, Graeme; Festa-Bianchet, Marco

2016-04-01

Reproduction can lead to a trade-off with growth, particularly when individuals reproduce before completing body growth. Kangaroos have indeterminate growth and may always face this trade-off. We combined an experimental manipulation of reproductive effort and multi-year monitoring of a large sample size of marked individuals in two populations of eastern grey kangaroos to test the predictions (1) that reproduction decreases skeletal growth and mass gain and (2) that mass loss leads to reproductive failure. We also tested if sex-allocation strategies influenced these trade-offs. Experimental reproductive suppression revealed negative effects of reproduction on mass gain and leg growth from 1 year to the next. Unmanipulated females, however, showed a positive correlation between number of days lactating and leg growth over periods of 2 years and longer, suggesting that over the long term, reproductive costs were masked by individual heterogeneity in resource acquisition. Mass gain was necessary for reproductive success the subsequent year. Although mothers of daughters generally lost more mass than females nursing sons, mothers in poor condition experienced greater mass gain and arm growth if they had daughters than if they had sons. The strong links between individual mass changes and reproduction suggest that reproductive tactics are strongly resource-dependent.

A Null Space Control of Two Wheels Driven Mobile Manipulator Using Passivity Theory

Science.gov (United States)

Shibata, Tsuyoshi; Murakami, Toshiyuki

This paper describes a control strategy of null space motion of a two wheels driven mobile manipulator. Recently, robot is utilized in various industrial fields and it is preferable for the robot manipulator to have multiple degrees of freedom motion. Several studies of kinematics for null space motion have been proposed. However stability analysis of null space motion is not enough. Furthermore, these approaches apply to stable systems, but they do not apply unstable systems. Then, in this research, base of manipulator equips with two wheels driven mobile robot. This robot is called two wheels driven mobile manipulator, which becomes unstable system. In the proposed approach, a control design of null space uses passivity based stabilizing. A proposed controller is decided so that closed-loop system of robot dynamics satisfies passivity. This is passivity based control. Then, control strategy is that stabilizing of the robot system applies to work space observer based approach and null space control while keeping end-effector position. The validity of the proposed approach is verified by simulations and experiments of two wheels driven mobile manipulator.

The cardiometabolic effect of current management of polycystic ovary syndrome: strategies of prevention and treatment.

Science.gov (United States)

Baldani, Dinka Pavicic; Skrgatic, Lana; Ougouag, Roya; Kasum, Miro

2018-02-01

Polycystic ovary syndrome (PCOS) is the commonest endocrine disorder amongst women of reproductive age, which is characterized by reproductive and cardiometabolic disturbances with long-term health repercussions. Insulin resistance (IR), impaired glucose tolerance, type 2 diabetes mellitus (DM2), obesity and dyslipidemia occur more in women with PCOS than in age-comparable women without PCOS. Long term data regarding risks or benefits of medical intervention for metabolic dysfunction of PCOS are lacking. Therapies, such as oral contraceptives (OCPs) and anti-androgenic medications used to manage the reproductive manifestations of PCOS, may themselves be the cause of cardiometabolic perturbations. Hence, strategies regarding the management of reproductive issues in PCOS encompass a patient-specific tailored approach. Factors that influence the cardiometabolic side effects arising during treatment of the reproductive manifestations of PCOS (hirsutism/anovulation) are also discussed in this paper in order to build future strategies to minimize the overall cardiometabolic risk.

An evaluation of the effect of altering nutrition and nutritional strategies in early lactation on reproductive performance and estrous behavior of high-yielding Holstein-Friesian dairy cows.

Science.gov (United States)

Gilmore, H S; Young, F J; Patterson, D C; Wylie, A R G; Law, R A; Kilpatrick, D J; Elliott, C T; Mayne, C S

2011-07-01

Reproductive performance in the high-yielding dairy cow has severely decreased in the last 40 yr. The aim of this study was to compare the effectiveness of 4 nutritional strategies in improving the reproductive performance of high-yielding dairy cows. It was hypothesized that offering cows a high-starch ration in early lactation would enhance the onset of luteal activity, and that decreasing the severity of negative energy balance in the early postcalving period would improve reproductive parameters. Nutritional regimens aimed at improving fertility were applied to 96 Holstein-Friesian dairy animals. Upon calving, animals were allocated in a balanced manner to one of 4 dietary treatments. Primiparous animals were balanced according to live weight, body condition score and calving date. Multiparous animals were balanced according to parity, previous lactation milk yield, liveweight, body condition score and calving date. Treatment 1 was based on an industry best practice diet (control) to contain 170 g of crude protein/kg of dry matter. Treatment 2 was an individual cow feeding strategy, whereby the energy balance (EB) of individual animals was managed so as to achieve a predetermined target daily EB profile (±10 MJ/d). Treatment 3 was a high-starch/high-fat combination treatment, whereby an insulinogenic (high-starch) diet was offered in early lactation to encourage cyclicity and followed by a lipogenic (low-starch, high-fat) diet to promote embryo development. Treatment 4 was a low-protein diet, containing 140 g of crude protein/kg of dry matter, supplemented with protected methionine at an inclusion level of 40 g per animal per day. The nutritional strategies implemented in this study had no statistically significant effects on cow fertility measures, which included the onset of luteal activity, conception rate, in-calf rate, and the incidence of atypical cycles. The individual cow feeding strategy improved EB in early lactation but had no benefit on conception

Pollinator-Driven Speciation in Sexually Deceptive Orchids

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Shuqing Xu

2012-01-01

Full Text Available Pollinator-mediated selection has been suggested to play a major role for the origin and maintenance of the species diversity in orchids. Sexually deceptive orchids are one of the prime examples for rapid, pollinator-mediated plant radiations, with many species showing little genetic differentiation, lack of postzygotic barriers, but strong prezygotic reproductive isolation. These orchids mimic mating signals of female insects and employ male insects as pollinators. This kind of sexual mimicry leads to highly specialised pollination and provides a good system for investigating the process of pollinator-driven speciation. Here, we summarise the knowledge of key processes of speciation in this group of orchids and conduct a meta-analysis on traits that contribute to species differentiation, and thus potentially to speciation. Our study suggests that pollinator shift through changes in floral scent is predominant among closely related species in sexually deceptive orchids. Such shifts can provide a mechanism for pollinator-driven speciation in plants, if the resulting floral isolation is strong. Furthermore, changes in floral scent in these orchids are likely controlled by few genes. Together these factors suggest speciation in sexually deceptive orchids may happen rapidly and even in sympatry, which may explain the remarkable species diversity observed in this plant group.

South Africa’s freight rail reform: A demand-driven perspective

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Jan H. Havenga

2014-11-01

Full Text Available During the 20th century, freight transport in South Africa was employed to attain politicoeconomic ideals, resulting in the overprotection of rail and overregulation of road transport. Increasing industry pressure, combined with the international deregulation trend, led to deregulation in 1988. Myopia resulted in a rail investment hiatus and exponential growth in high-value, long-distance road transport, causing excessive logistics and externality costs for the country. The aim of this study was to propose a freight rail reform agenda based on, (1 lessons from past freight transport policy efforts and (2 the results of freight transport market segmentation driven by models developed over the past two decades. For the study, freight flows were modelled by disaggregating the national input–output model into 372 origin–destination pairs and 71 commodity groups, followed by distance decay gravitymodelling. Logistics costs were calculated by relating commodity-level freight flows to the costs of fulfilling associated logistical functions. The standard management approach of founding strategy development on market-driven segmentation provides a neutral input to steer rail reform discussions in South Africa. Market segmentation points to a dualistic rail reform agenda, enabling both a profit-driven core and a development-driven branch line network. Freight flow insights are steering the policy reform debate towards long-term freight strategy development and optimal freight logistics network design.

Nutritional and environmental effects on reproduction in small ruminants.

Science.gov (United States)

Martin, G B; Rodger, J; Blache, D

2004-01-01

Animals live in environments that are both complex and continually changing, so they have to respond to short- and long-term variations in a wide range of factors, such as photoperiod, nutrition and sociosexual signals. Before they were domesticated, animals developed reproductive strategies that coped with these changes and often took advantage of them. The physiological processes that implement these strategies have been modified to some extent during several millennia of controlled breeding, but most persist. Thus, many genotypes still exhibit profound responses to external inputs, such as the induction of ovulation by sociosexual signals and the doubling of litter size by a change in nutrition. The complexity in these responses is now becoming clearer. For example, with sociosexual signals, we now need to consider the stimulatory effects of males on females, of females on males and of females on females. Similarly, the impact of nutrition has been extended beyond the control of puberty and the production of gametes to include phenomena such as 'fetal programming', with its potentially profound effects on the life-long performance of the animals. Fortunately, our capacity to research these phenomena has been greatly enhanced by technical improvements in hormone assays, molecular and cellular biology, and real-time ultrasound. This has brought us a better understanding of several of the environmental influences on reproduction, including: the cellular processes within ovarian follicles that mediate the effect of nutrition on ovulation rate; the neuroendocrine pathways through which nutritional inputs affect the brain centres that control appetite and reproduction; and the intracerebral pathways through which sociosexual signals (olfactory and non-olfactory) stimulate the reproductive axis. Importantly, we are now beginning to realise that, as well as considering interactions between environmental inputs and genotype, we need to take into account interactions

A comparison of information functions and search strategies for sensor planning in target classification.

Science.gov (United States)

Zhang, Guoxian; Ferrari, Silvia; Cai, Chenghui

2012-02-01

This paper investigates the comparative performance of several information-driven search strategies and decision rules using a canonical target classification problem. Five sensor models are considered: one obtained from classical estimation theory and four obtained from Bernoulli, Poisson, binomial, and mixture-of-binomial distributions. A systematic approach is presented for deriving information functions that represent the expected utility of future sensor measurements from mutual information, Rènyi divergence, Kullback-Leibler divergence, information potential, quadratic entropy, and the Cauchy-Schwarz distance. The resulting information-driven strategies are compared to direct-search, alert-confirm, task-driven (TS), and log-likelihood-ratio (LLR) search strategies. Extensive numerical simulations show that quadratic entropy typically leads to the most effective search strategy with respect to correct-classification rates. In the presence of prior information, the quadratic-entropy-driven strategy also displays the lowest rate of false alarms. However, when prior information is absent or very noisy, TS and LLR strategies achieve the lowest false-alarm rates for the Bernoulli, mixture-of-binomial, and classical sensor models.

Using mariculture as a breeding site: reproduction of Hypleurochilus fissicornis (Actinopterygii: Blenniidae

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Bianca Possamai

2015-09-01

Full Text Available Mariculture in estuaries provides substrate for colonization by fouling organisms, thus attracting small cryptic fish species hitherto unknown in this environment. The blenny Hypleurochilus fissicornis is one of the species that is associated with this new system and is found in high abundance in bivalve farming. To understand the reproductive strategy that this species uses in this new environment, we collected specimens monthly in a mariculture on the southern coast of Paraná State (Brazil. After obtaining morphometric data, we removed gonads to determine sex and maturity stage. Gonads were weighed and analysed histologically. Oogenesis showed the same pattern as in other teleosts, but spermatogenesis showed a very complex dynamics. The spawning is multiple and synchronous between sexes, lasting eight months (May to December and peaking in winter. Hypleurochilus fissicornis was reproductively successful using the mariculture as a breeding site. The species has a variety of tactics to protect its offspring (e.g. batch spawning, long reproductive period, reduced L50, parental care and a reproductive peak in winter.

Behavioural Motives of Acquisition of Solar-driven Equipment

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Shkurupska Iryna O.

2013-12-01

Full Text Available The article identifies needs of the target group, namely structure of motives, which justify making a decision to buy, in order to create efficient marketing strategy of an enterprise, which sell solar-driven equipment in Ukraine. There are five segments in the domestic market of helio-systems: individual consumers, recreation industry, agrarian industry, construction and social spheres. The article allocates 15 motives of acquisition of the solar-driven equipment for these segments, the most important of which are price, availability of solar energy, alternative price and energy saving. Besides, the structure of such motives is determined for each segment individually. In order to choose specific marketing instruments in the policy of promotion of solar-driven equipment, the article identifies differences in the form of goals of use and motives of acquisition between the specified consumer segments. The article reveals certain barriers that interfere with acquisition of solar-driven equipment – low level of trust into helio-systems, conservatism of consumers, absence of free applications for consumers – overcoming which is only possible with the help of certain marketing actions.

Reorienting development: towards and engendered employment strategy

OpenAIRE

Selim Jahan

2005-01-01

Development strategies, in the name of gender-neutral, are gender-blind. The gender blindness of development strategies are derived from the gender-insensitiveness of dominant development paradigms, which, in the name of work, do not make any distinction between productive and reproductive work and does not differentiate, in the name of household, the asymmetries faced by its different members on the basis of sex. Given the nature of gender blindness of development strategies, it is clear tha...

Exploring African-American and Latino Teens' Perceptions of Contraception and Access to Reproductive Health Care Services

OpenAIRE

Galloway, Charlotte T.; Duffy, Jennifer L.; Dixon, Rena P.; Fuller, Taleria R.

2017-01-01

Purpose Reducing disparities in teen pregnancy and birth rates among African American and Latina teens is a central focus of a community-wide teen pregnancy prevention initiative implemented by the South Carolina Campaign to Prevent Teen Pregnancy. Disparities in teen pregnancy and birth rates are driven, in part, by differential access to contraception and reproductive health care services. The purpose of this qualitative study was to understand African American and Latino teens? 1) preferen...

Temperature-induced physiological stress and reproductive characteristics of the migratory seahorse Hippocampus erectus during a thermal stress simulation.

Science.gov (United States)

Qin, Geng; Johnson, Cara; Zhang, Yuan; Zhang, Huixian; Yin, Jianping; Miller, Glen; Turingan, Ralph G; Guisbert, Eric; Lin, Qiang

2018-05-15

Inshore-offshore migration occurs frequently in seahorse species either because of prey opportunities or because it is driven by reproduction, and variations in water temperature may dramatically change migratory seahorse behavior and physiology. The present study investigated the behavioral and physiological responses of the lined seahorse Hippocampus erectus under thermal stress and evaluated the potential effects of different temperatures on its reproduction. The results showed that the thermal tolerance of the seahorses was time dependent. Acute thermal stress (30°C, 2-10 hours) increased the basal metabolic rate (breathing rate) and the expression of stress response genes ( Hsp genes) significantly and further stimulated seahorse appetite. Chronic thermal treatment (30°C, 4 weeks) led to a persistently higher basal metabolic rate, higher stress response gene expression, and higher mortality, indicating that the seahorses could not acclimate to chronic thermal stress and might experience massive mortality due to excessive basal metabolic rates and stress damage. Additionally, no significant negative effects on gonad development or reproductive endocrine regulation genes were observed in response to chronic thermal stress, suggesting that seahorse reproductive behavior could adapt to higher-temperature conditions during migration and within seahorse breeding grounds. In conclusion, this simulation experiment indicated that temperature variations during inshore-offshore migration have no effect on reproduction but promote basal metabolic rates and stress responses significantly. Therefore, we suggest that the high observed tolerance of seahorse reproduction was in line with the inshore-offshore reproductive migration pattern of lined seahorse. © 2018. Published by The Company of Biologists Ltd.

Optimal resource allocation to survival and reproduction in parasitic wasps foraging in fragmented habitats.

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Eric Wajnberg

Full Text Available Expansion and intensification of human land use represents the major cause of habitat fragmentation. Such fragmentation can have dramatic consequences on species richness and trophic interactions within food webs. Although the associated ecological consequences have been studied by several authors, the evolutionary effects on interacting species have received little research attention. Using a genetic algorithm, we quantified how habitat fragmentation and environmental variability affect the optimal reproductive strategies of parasitic wasps foraging for hosts. As observed in real animal species, the model is based on the existence of a negative trade-off between survival and reproduction resulting from competitive allocation of resources to either somatic maintenance or egg production. We also asked to what degree plasticity along this trade-off would be optimal, when plasticity is costly. We found that habitat fragmentation can indeed have strong effects on the reproductive strategies adopted by parasitoids. With increasing habitat fragmentation animals should invest in greater longevity with lower fecundity; yet, especially in unpredictable environments, some level of phenotypic plasticity should be selected for. Other consequences in terms of learning ability of foraging animals were also observed. The evolutionary consequences of these results are discussed.

Religious People Are Trusted Because They Are Viewed as Slow Life-History Strategists.

Science.gov (United States)

Moon, Jordan W; Krems, Jaimie Arona; Cohen, Adam B

2018-03-01

Religious people are more trusted than nonreligious people. Although most theorists attribute these perceptions to the beliefs of religious targets, religious individuals also differ in behavioral ways that might cue trust. We examined whether perceivers might trust religious targets more because they heuristically associate religion with slow life-history strategies. In three experiments, we found that religious targets are viewed as slow life-history strategists and that these findings are not the result of a universally positive halo effect; that the effect of target religion on trust is significantly mediated by the target's life-history traits (i.e., perceived reproductive strategy); and that when perceivers have direct information about a target's reproductive strategy, their ratings of trust are driven primarily by his or her reproductive strategy, rather than religion. These effects operate over and above targets' belief in moralizing gods and offer a novel theoretical perspective on religion and trust.

Patterns of globalized reproduction: Egg cells regulation in Israel and Austria.

Science.gov (United States)

Shalev, Carmel; Werner-Felmayer, Gabriele

2012-04-18

Since the successful introduction of in vitro fertilization in 1978, medically assisted reproduction (MAR) has proliferated in multiple clinical innovations. Consequently, egg cells have become an object of demand for both infertility treatment and stem cell research, and this raises complex legal, ethical, social and economic issues.In this paper we compare how the procurement and use of human egg cells is regulated in two countries: Israel and Austria. Israel is known for its scientific leadership, generous public funding, high utilization and liberal regulation of assisted reproductive technology (ART). Austria lies at the other extreme of the regulatory spectrum in terms of restrictions on reproductive interventions.In both countries, however, there is a constant increase in the use of the technology, and recent legal developments make egg cells more accessible. Also, in both countries the scarcity of egg cells in concert with the rising demand for donations has led to the emergence of cross-border markets and global 'reproductive tourism' practices. In Israel, in particular, a scandal known as the 'eggs affair' was followed by regulation that allowed egg cell donations from outside the country under certain conditions.Cross-border markets are developed by medical entrepreneurs, driven by global economic gaps, made possible by trans-national regulatory lacunae and find expression as consumer demand. The transnational practice of egg cell donations indicates the emergence of a global public health issue, but there is a general lack of medical and epidemiological data on its efficacy and safety. We conclude that there is need for harmonisation of domestic laws and formulation of new instruments for international governance.

Patterns of globalized reproduction: Egg cells regulation in Israel and Austria

Directory of Open Access Journals (Sweden)

Shalev Carmel

2012-04-01

Full Text Available Abstract Since the successful introduction of in vitro fertilization in 1978, medically assisted reproduction (MAR has proliferated in multiple clinical innovations. Consequently, egg cells have become an object of demand for both infertility treatment and stem cell research, and this raises complex legal, ethical, social and economic issues. In this paper we compare how the procurement and use of human egg cells is regulated in two countries: Israel and Austria. Israel is known for its scientific leadership, generous public funding, high utilization and liberal regulation of assisted reproductive technology (ART. Austria lies at the other extreme of the regulatory spectrum in terms of restrictions on reproductive interventions. In both countries, however, there is a constant increase in the use of the technology, and recent legal developments make egg cells more accessible. Also, in both countries the scarcity of egg cells in concert with the rising demand for donations has led to the emergence of cross-border markets and global 'reproductive tourism' practices. In Israel, in particular, a scandal known as the 'eggs affair' was followed by regulation that allowed egg cell donations from outside the country under certain conditions. Cross-border markets are developed by medical entrepreneurs, driven by global economic gaps, made possible by trans-national regulatory lacunae and find expression as consumer demand. The transnational practice of egg cell donations indicates the emergence of a global public health issue, but there is a general lack of medical and epidemiological data on its efficacy and safety. We conclude that there is need for harmonisation of domestic laws and formulation of new instruments for international governance.

The evolution of reproductive diversity in Afrobatrachia: A phylogenetic comparative analysis of an extensive radiation of African frogs

Science.gov (United States)

Portik, Daniel M.; Blackburn, David C.

2016-01-01

The reproductive modes of anurans (frogs and toads) are the most diverse of terrestrial vertebrates, and a major challenge is identifying selective factors that promote the evolution or retention of reproductive modes across clades. Terrestrialized anuran breeding strategies have evolved repeatedly from the plesiomorphic fully aquatic reproductive mode, a process thought to occur through intermediate reproductive stages. Several selective forces have been proposed for the evolution of terrestrialized reproductive traits, but factors such as water systems and co‐evolution with ecomorphologies have not been investigated. We examined these topics in a comparative phylogenetic framework using Afrobatrachian frogs, an ecologically and reproductively diverse clade representing more than half of the total frog diversity found in Africa (∼400 species). We infer direct development has evolved twice independently from terrestrialized reproductive modes involving subterranean or terrestrial oviposition, supporting evolution through intermediate stages. We also detect associations between specific ecomorphologies and oviposition sites, and demonstrate arboreal species exhibit an overall shift toward using lentic water systems for breeding. These results indicate that changes in microhabitat use associated with ecomorphology, which allow access to novel sites for reproductive behavior, oviposition, or larval development, may also promote reproductive mode diversity in anurans. PMID:27402182

Reproductive strategies and colonizing ability of two sympatric epiphytic bromeliads in a tropical premontane area

NARCIS (Netherlands)

Cascante Marin, A.M.; de Jong, M.; Borg, E.D.; Oostermeijer, J.G.B.; Wolf, J.H.D.; den Nijs, J.C.M.

2006-01-01

Predispersal characteristics that affect the reproductive success in plants may influence their colonizing ability. We evaluated this hypothesis in two sympatric epiphytic bromeliads in Costa Rica, Guzmania monostacbia and Tillandsia fasciculata, that show contrasting levels of local seedling

Variations upon a theme: Australian lizards provide insights into the endocrine control of vertebrate reproductive cycles.

Science.gov (United States)

Jones, Susan M

2017-04-01

Australian lizards exhibit a broad array of different reproductive strategies and provide an extraordinary diversity and range of models with which to address fundamental problems in reproductive biology. Studies on lizards have frequently led to new insights into hormonal regulatory pathways or mechanisms of control, but we have detailed knowledge of the reproductive cycle in only a small percentage of known species. This review provides an overview and synthesis of current knowledge of the hormonal control of reproductive cycles in Australian lizards. Agamid lizards have provided useful models with which to test hypotheses about the hormonal regulation of the expression of reproductive behaviors, while research on viviparous skinks is providing insights into the evolution of the endocrine control of gestation. However, in order to better understand the potential risks that environmental factors such as climate change and endocrine disrupting chemicals pose to our fauna, better knowledge is required of the fundamental characteristics of the reproductive cycle in a broader range of lizard species. Copyright © 2015 Elsevier Inc. All rights reserved.

Current brood size and residual reproductive value predict brood desertion in the burying beetle Nicrophorus vespilloides

OpenAIRE

Ward, R. J. S.; Cotter, S. C.; Kilner, R. M.

2009-01-01

Life-history theory suggests that offspring desertion can be an adaptive reproductive strategy, in which parents forgo the costly care of an unprofitable current brood to save resources for future reproduction. In the burying beetle, Nicrophorus vespilloides, parents commonly abandon their offspring to the care of others, resulting in female-only care, male-only care, brood parasitism, and the care of offspring sired by satellite males. Furthermore, when there is biparental care, males routin...

Network-level reproduction number and extinction threshold for vector-borne diseases.

Science.gov (United States)

Xue, Ling; Scoglio, Caterina

2015-06-01

The basic reproduction number of deterministic models is an essential quantity to predict whether an epidemic will spread or not. Thresholds for disease extinction contribute crucial knowledge of disease control, elimination, and mitigation of infectious diseases. Relationships between basic reproduction numbers of two deterministic network-based ordinary differential equation vector-host models, and extinction thresholds of corresponding stochastic continuous-time Markov chain models are derived under some assumptions. Numerical simulation results for malaria and Rift Valley fever transmission on heterogeneous networks are in agreement with analytical results without any assumptions, reinforcing that the relationships may always exist and proposing a mathematical problem for proving existence of the relationships in general. Moreover, numerical simulations show that the basic reproduction number does not monotonically increase or decrease with the extinction threshold. Consistent trends of extinction probability observed through numerical simulations provide novel insights into mitigation strategies to increase the disease extinction probability. Research findings may improve understandings of thresholds for disease persistence in order to control vector-borne diseases.

Ecology-driven stereotypes override race stereotypes

OpenAIRE

Williams, Keelah E. G.; Sng, Oliver; Neuberg, Steven L.

2015-01-01

Ecological features shape people’s goals, strategies, and behaviors. Our research suggests that social perceivers possess a lay understanding of ecology’s influence on behavior, resulting in ecology-driven stereotypes. Moreover, because race is confounded with ecology in the United States, Americans’ stereotypes about racial groups may actually reflect their stereotypes about these groups’ presumed home ecologies. In a series of studies, we demonstrate that (i) individuals possess ecology-dri...

Alterations in flowering strategies and sexual allocation of Caragana stenophylla along a climatic aridity gradient

OpenAIRE

Lina Xie; Hongyu Guo; Chengcang Ma

2016-01-01

Plant can alter reproductive strategies for adaptation to different environments. However, alterations in flowering strategies and sexual allocation for the same species growing in different environments still remain unclear. We examined the sexual reproduction parameters of Caragana stenophylla across four climatic zones from semi-arid, arid, very arid, to intensively arid zones in the Inner Mongolia Steppe, China. Under the relatively favorable climatic conditions of semi-arid zone, C. sten...

An individual reproduction model sensitive to milk yield and body condition in Holstein dairy cows.

Science.gov (United States)

Brun-Lafleur, L; Cutullic, E; Faverdin, P; Delaby, L; Disenhaus, C

2013-08-01

To simulate the consequences of management in dairy herds, the use of individual-based herd models is very useful and has become common. Reproduction is a key driver of milk production and herd dynamics, whose influence has been magnified by the decrease in reproductive performance over the last decades. Moreover, feeding management influences milk yield (MY) and body reserves, which in turn influence reproductive performance. Therefore, our objective was to build an up-to-date animal reproduction model sensitive to both MY and body condition score (BCS). A dynamic and stochastic individual reproduction model was built mainly from data of a single recent long-term experiment. This model covers the whole reproductive process and is composed of a succession of discrete stochastic events, mainly calving, ovulations, conception and embryonic loss. Each reproductive step is sensitive to MY or BCS levels or changes. The model takes into account recent evolutions of reproductive performance, particularly concerning calving-to-first ovulation interval, cyclicity (normal cycle length, prevalence of prolonged luteal phase), oestrus expression and pregnancy (conception, early and late embryonic loss). A sensitivity analysis of the model to MY and BCS at calving was performed. The simulated performance was compared with observed data from the database used to build the model and from the bibliography to validate the model. Despite comprising a whole series of reproductive steps, the model made it possible to simulate realistic global reproduction outputs. It was able to well simulate the overall reproductive performance observed in farms in terms of both success rate (recalving rate) and reproduction delays (calving interval). This model has the purpose to be integrated in herd simulation models to usefully test the impact of management strategies on herd reproductive performance, and thus on calving patterns and culling rates.

Socioeconomic status, education, and reproduction in modern women: an evolutionary perspective.

Science.gov (United States)

Huber, Susanne; Bookstein, Fred L; Fieder, Martin

2010-01-01

Although associations between status or resources and reproduction are positive in premodern societies and also in men in modern societies, in modern women the associations are typically negative. We investigated how the association between socioeconomic status and reproductive output varies with the source of status and resources, the woman's education, and her age at reproductive onset (proxied by age at marriage). By using a large sample of US women, we examined the association between a woman's reproductive output and her own and her husband's income and education. Education, income, and age at marriage are negatively associated with a woman's number of children and increase her chances of childlessness. Among the most highly educated two-thirds of the sample of women, husband's income predicts the number of children. The association between a woman's number of children and her husband's income turns from positive to negative when her education and age at marriage is low (even though her mean offspring number rises at the same time). The association between a woman's own income and her number of children is negative, regardless of education. Rather than maximizing the offspring number, these modern women seem to adjust investment in children based on their family size and resource availability. Striving for resources seems to be part of a modern female reproductive strategy--but, owing to costs of resource acquisition, especially higher education, it may lead to lower birthrates: a possible evolutionary explanation of the demographic transition, and a complement to the human capital theory of net reproductive output. (c) 2010 Wiley-Liss, Inc.

Reproductive strategies in black scabbardfish (Aphanopus carbo Lowe, 1839 from the NE Atlantic

Directory of Open Access Journals (Sweden)

Ana Neves

2009-12-01

Full Text Available Gonads of the NE Atlantic black scabbardfish were examined to give an insight into the reproductive biology of this species. It was concluded that black scabbardfish had determinate fecundity because: (i a distinct hiatus in oocyte size was observed between pre-vitellogenic and vitellogenic oocytes; (ii vitellogenic oocytes increased in size during the spawning season; (iii the number of vitellogenic oocytes did not increase during the spawning season; and (iv the intensity of atresia was low in pre-spawning and spawning ovaries. Fecundity estimates ranged from 73 to 373 oocytes g-1 female. Comparison of developing ovaries from mainland Portugal and Madeira revealed that those from Madeira were more advanced in development, with more cortical alveoli stage oocytes and a higher gonadosomatic index. Starting in July, the reproductive development of all females from mainland Portugal was interrupted by a generalised atresia of developing oocytes. Completion of gametogenesis and spawning only occurred for fish from Madeira but some fish from this area also failed to complete oocyte development due to mass follicular atresia of vitellogenic oocytes. The percentage of Madeiran fish that failed to spawn due to follicular atresia ranged from 21.2% in 2006 to 37.4% in 2005.

Supporting Beacon and Event-Driven Messages in Vehicular Platoons through Token-Based Strategies.

Science.gov (United States)

Balador, Ali; Uhlemann, Elisabeth; Calafate, Carlos T; Cano, Juan-Carlos

2018-03-23

Timely and reliable inter-vehicle communications is a critical requirement to support traffic safety applications, such as vehicle platooning. Furthermore, low-delay communications allow the platoon to react quickly to unexpected events. In this scope, having a predictable and highly effective medium access control (MAC) method is of utmost importance. However, the currently available IEEE 802.11p technology is unable to adequately address these challenges. In this paper, we propose a MAC method especially adapted to platoons, able to transmit beacons within the required time constraints, but with a higher reliability level than IEEE 802.11p, while concurrently enabling efficient dissemination of event-driven messages. The protocol circulates the token within the platoon not in a round-robin fashion, but based on beacon data age, i.e., the time that has passed since the previous collection of status information, thereby automatically offering repeated beacon transmission opportunities for increased reliability. In addition, we propose three different methods for supporting event-driven messages co-existing with beacons. Analysis and simulation results in single and multi-hop scenarios showed that, by providing non-competitive channel access and frequent retransmission opportunities, our protocol can offer beacon delivery within one beacon generation interval while fulfilling the requirements on low-delay dissemination of event-driven messages for traffic safety applications.

Supporting Beacon and Event-Driven Messages in Vehicular Platoons through Token-Based Strategies

Directory of Open Access Journals (Sweden)

Ali Balador

2018-03-01

Full Text Available Timely and reliable inter-vehicle communications is a critical requirement to support traffic safety applications, such as vehicle platooning. Furthermore, low-delay communications allow the platoon to react quickly to unexpected events. In this scope, having a predictable and highly effective medium access control (MAC method is of utmost importance. However, the currently available IEEE 802.11p technology is unable to adequately address these challenges. In this paper, we propose a MAC method especially adapted to platoons, able to transmit beacons within the required time constraints, but with a higher reliability level than IEEE 802.11p, while concurrently enabling efficient dissemination of event-driven messages. The protocol circulates the token within the platoon not in a round-robin fashion, but based on beacon data age, i.e., the time that has passed since the previous collection of status information, thereby automatically offering repeated beacon transmission opportunities for increased reliability. In addition, we propose three different methods for supporting event-driven messages co-existing with beacons. Analysis and simulation results in single and multi-hop scenarios showed that, by providing non-competitive channel access and frequent retransmission opportunities, our protocol can offer beacon delivery within one beacon generation interval while fulfilling the requirements on low-delay dissemination of event-driven messages for traffic safety applications.

Normal Female Reproductive Anatomy

Science.gov (United States)

... historical Searches are case-insensitive Reproductive System, Female, Anatomy Add to My Pictures View /Download : Small: 720x756 ... Large: 3000x3150 View Download Title: Reproductive System, Female, Anatomy Description: Anatomy of the female reproductive system; drawing ...

Avian reproductive physiology

Science.gov (United States)

Gee, G.F.; Gibbons, Edward F.; Durrant, Barbara S.; Demarest, Jack

1995-01-01

Knowledge of the many physiological factors associated with egg production , fertility, incubation, and brooding in nondomestic birds is limited. Science knows even less about reproduction in most of the 238 endangered or threatened birds. This discussion uses studies of nondomestic and, when necessary, domestic birds to describe physiological control of reproduction. Studies of the few nondomestic avian species show large variation in physiological control of reproduction. Aviculturists, in order to successfully propagate an endangered bird, must understand the bird's reproductive peculiarities. First, investigators can do studies with carefully chosen surrogate species, but eventually they need to confirm the results in the target endangered bird. Studies of reproduction in nondomestic birds increased in the last decade. Still, scientists need to do more comparative studies to understand the mechanisms that control reproduction in birds. New technologies are making it possible to study reproductive physiology of nondomestic species in less limiting ways. These technologies include telemetry to collect information without inducing stress on captives (Howey et al., 1987; Klugman, 1987), new tests for most of the humoral factors associated with reproduction, and the skill to collect small samples and manipulate birds without disrupting the physiological mechanisms (Bercovitz et al., 1985). Managers are using knowledge from these studies to improve propagation in zoological parks, private and public propagation facilities, and research institutions. Researchers need to study the control of ovulation, egg formation, and oviposition in the species of nondomestic birds that lay very few eggs in a season, hold eggs in the oviduct for longer intervals, or differ in other ways from the more thoroughly studied domestic birds. Other techniques that would enhance propagation for nondomestlc birds include tissue culture of cloned embryonic cells, cryopreservation of embryos

Reproduction, physiology and biochemistry

Science.gov (United States)

This chapter summarizes fundamental knowledge and recent discoveries about the reproduction, physiology and biochemistry of plant-parasitic nematodes. Various types of reproduction are reviewed, including sexual reproduction and mitotic and meiotic parthenogenesis. Although much is known about the p...

A Cost Benefit Analysis of an Accelerator Driven Transmutation System

International Nuclear Information System (INIS)

Westlen, D.; Gudowski, W.; Wallenius, J.; Tucek, K.

2002-01-01

This paper estimates the economical costs and benefits associated with a nuclear waste transmutation strategy. An 800 MWth, fast neutron spectrum, subcritical core design has been used in the study (the so called Sing-Sing Core). Three different fuel cycle scenarios have been compared. The main purpose of the paper has been to identify the cost drivers of a partitioning and transmutation strategy, and to estimate the cost of electricity generated in a nuclear park with operating accelerator driven systems. It has been found that directing all transuranic discharges from spent light water reactor (LWR) uranium oxide (UOX) fuel to accelerator driven systems leads to a cost increase for nuclear power of 50±15%, while introduction of a mixed oxide (MOX) burning step in the LWRs diminishes the cost penalty to 35±10%. (authors)

Fish reproduction

National Research Council Canada - National Science Library

Rocha, Maria João; Arukwe, Augustine; Kapoor, B. G

2008-01-01

... of reproductive systems is essential for such studies. Fishes comprise over 28,000 species, with a remarkable variability in morphology, physiology and environmental adaptation. Knowledge on fish reproduction is scattered across numerous sources that shows a dynamic research field. The Editors believe it to be an opportune moment for a...

Equity and financing for sexual and reproductive health service delivery: current innovations.

Science.gov (United States)

Montagu, Dominic; Graff, Maura

2009-07-01

National and international decisions on financing for sexual and reproductive health (SRH) services have profound effects on the type, unit costs and distribution of SRH commodities and services produced, and on their availability and consumption. Much international and national funding is politically driven and is doing little for equity and quality improvement. Financing remains a significant challenge in most developing countries and demands creative responses. While no "one-size-fits-all" solution exists, there are numerous ongoing examples of successful innovations, many of which are focusing on resource pooling and on purchasing or subsidising SRH services. In this article we have used interviews, grey literature and presentations made at a range of recent public fora to identify new and innovative ways of financing SRH services so as to increase equity in developing countries. Because SRH services are often of low value as a personal good but high value as a public good, we summarise the issues from a societal perspective, highlighting the importance of financing and policy decisions for SRH services. We provide a structured overview of what novel approaches to financing appear to have positive effects in a range of developing countries. Targeting, government payment mechanisms, subsidy delivery and co-financing for sustainability are highlighted as showing particular promise. Examples are used throughout the article to illustrate innovative strategies.

[Protection of reproductive functions in patients with tumors].

Science.gov (United States)

Snajderová, M; Mardesić, T; Ganevová, M; Malinová, B

2002-08-16

Survival from cancer continues to improve. Antimitotic therapy can induce failure of spermatogenesis and oogenesis, gonadal disturbances and infertility. Recent advances in reproductive medicine have opened opportunities for the preservation of reproductive potential of patients with cancer. The aim of our study was to analyse by a multidisciplinary team the contemporary state of art and proposal of the Czech model of fertility preservation starting in childhood and continuing through the whole reproductive period. This paper highlights the problems associated with gonadal failure as a consequence of therapy for malignancy in childhood, adolescence and adulthood. Analysis of these problems served as a principle for the management strategy for fertility preservation. Patients undergoing treatment for malignancy are at the high risk of gonadal damage and infertility. Therefore, alternative treatments with less gonadal toxicity and different treatment protocols were evaluated. Fertility can be preserved with the freezing and banking of spermatozoa, embryos, and oocytes obtained prior to the cancer treatment. In female patients (starting in puberty) pharmacological preservation of gonads with gonadoliberin analogues is also possible. Chance for the future fertility preservation for children offers freezing and thawing of primordial follicles and spermatozoa obtained during the gonadal biopsies. Long-term follow-up study by a multidisciplinary medical team is necessary.

Nest fidelity is driven by multi-scale information in a long-lived seabird.

Science.gov (United States)

Robert, Alexandre; Paiva, Vítor H; Bolton, Mark; Jiguet, Frédéric; Bried, Joël

2014-10-22

Although the reproductive success of most organisms depends on factors acting at several spatial scales, little is known about how organisms are able to synthesize multi-scale information to optimize reproduction. Using longitudinal data from a long-lived seabird, Monteiro's storm-petrel, we show that average breeding success is strongly related to oceanic conditions at the population level, and we postulate that (i) individuals use proximal information (their own reproduction outcome in year t) to assess the qualities of their mate and nest and to decide to retain them or not in year t + 1; (ii) the intensity of these responses depends on the quality of the oceanic environment in year t, which affects the predictability of reproduction outcome in year t + 1. Our results confirm that mate and nest fidelities are higher following successful reproduction and that the relationship between the success of a given pair and subsequent nest fidelity is stronger in years with unfavourable oceanic conditions, suggesting that individuals rely on distant information to modulate their use of proximal information and adjust their breeding strategy. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Steroidogenic versus Metabolic Programming of Reproductive Neuroendocrine, Ovarian and Metabolic Dysfunctions.

Science.gov (United States)

Cardoso, Rodolfo C; Puttabyatappa, Muraly; Padmanabhan, Vasantha

2015-01-01

The susceptibility of the reproductive system to early exposure to steroid hormones has become a major concern in our modern societies. Human fetuses are at risk of abnormal programming via exposure to endocrine disrupting chemicals, inadvertent use of contraceptive pills during pregnancy, as well as from excess exposure to steroids due to disease states. Animal models provide an unparalleled resource to understand the developmental origin of diseases. In female sheep, prenatal exposure to testosterone excess results in an array of adult reproductive disorders that recapitulate those seen in women with polycystic ovary syndrome (PCOS), including disrupted neuroendocrine feedback mechanisms, increased pituitary sensitivity to gonadotropin-releasing hormone, luteinizing hormone excess, functional hyperandrogenism, and multifollicular ovarian morphology culminating in early reproductive failure. Prenatal testosterone treatment also leads to fetal growth retardation, insulin resistance, and hypertension. Mounting evidence suggests that developmental exposure to an improper steroidal/metabolic environment may mediate the programming of adult disorders in prenatal testosterone-treated females, and these defects are maintained or amplified by the postnatal sex steroid and metabolic milieu. This review addresses the steroidal and metabolic contributions to the development and maintenance of the PCOS phenotype in the prenatal testosterone-treated sheep model, including the effects of prenatal and postnatal treatment with an androgen antagonist or insulin sensitizer as potential strategies to prevent/ameliorate these dysfunctions. Insights obtained from these intervention strategies on the mechanisms underlying these defects are likely to have translational relevance to human PCOS. © 2015 S. Karger AG, Basel.

Stakeholder-driven geospatial modeling for assessing tsunami vertical-evacuation strategies in the U.S. Pacific Northwest

Science.gov (United States)

Wood, N. J.; Schmidtlein, M.; Schelling, J.; Jones, J.; Ng, P.

2012-12-01

State of Washington Emergency Management Division. Models of the influence of stakeholder-driven VE options identified changes in the type and distribution of at-risk individuals. Insights from VE use and performance as an aid to evacuations from the 2011 Tohoku tsunami helped to inform the meetings and the analysis. We developed geospatial tools to automate parts of the pedestrian-evacuation models to support the iterative process of developing VE options and forecasting changes in population exposure. Our summary presents the interdisciplinary effort to forecast population impacts from near-field tsunami threats and to develop effective VE strategies to minimize fatalities in future events.

A Data-Driven Modeling Strategy for Smart Grid Power Quality Coupling Assessment Based on Time Series Pattern Matching

Directory of Open Access Journals (Sweden)

Hao Yu

2018-01-01

Full Text Available This study introduces a data-driven modeling strategy for smart grid power quality (PQ coupling assessment based on time series pattern matching to quantify the influence of single and integrated disturbance among nodes in different pollution patterns. Periodic and random PQ patterns are constructed by using multidimensional frequency-domain decomposition for all disturbances. A multidimensional piecewise linear representation based on local extreme points is proposed to extract the patterns features of single and integrated disturbance in consideration of disturbance variation trend and severity. A feature distance of pattern (FDP is developed to implement pattern matching on univariate PQ time series (UPQTS and multivariate PQ time series (MPQTS to quantify the influence of single and integrated disturbance among nodes in the pollution patterns. Case studies on a 14-bus distribution system are performed and analyzed; the accuracy and applicability of the FDP in the smart grid PQ coupling assessment are verified by comparing with other time series pattern matching methods.

Reproductive seasonality in captive wild ruminants: implications for biogeographical adaptation, photoperiodic control, and life history.

Science.gov (United States)

Zerbe, Philipp; Clauss, Marcus; Codron, Daryl; Bingaman Lackey, Laurie; Rensch, Eberhard; Streich, Jürgen W; Hatt, Jean-Michel; Müller, Dennis W H

2012-11-01

Many ruminant species show seasonal patterns of reproduction. Causes for this are widely debated, and include adaptations to seasonal availability of resources (with cues either from body condition in more tropical, or from photoperiodism in higher latitude habitats) and/or defence strategies against predators. Conclusions so far are limited to datasets with less than 30 species. Here, we use a dataset on 110 wild ruminant species kept in captivity in temperate-zone zoos to describe their reproductive patterns quantitatively [determining the birth peak breadth (BPB) as the number of days in which 80% of all births occur]; then we link this pattern to various biological characteristics [latitude of origin, mother-young-relationship (hider/follower), proportion of grass in the natural diet (grazer/browser), sexual size dimorphism/mating system], and compare it with reports for free-ranging animals. When comparing taxonomic subgroups, variance in BPB is highly correlated to the minimum, but not the maximum BPB, suggesting that a high BPB (i.e. an aseasonal reproductive pattern) is the plesiomorphic character in ruminants. Globally, latitude of natural origin is highly correlated to the BPB observed in captivity, supporting an overruling impact of photoperiodism on ruminant reproduction. Feeding type has no additional influence; the hider/follower dichotomy, associated with the anti-predator strategy of 'swamping', has additional influence in the subset of African species only. Sexual size dimorphism and mating system are marginally associated with the BPB, potentially indicating a facilitation of polygamy under seasonal conditions. The difference in the calculated Julian date of conception between captive populations and that reported for free-ranging ones corresponds to the one expected if absolute day length was the main trigger in highly seasonal species: calculated day length at the time of conception between free-ranging and captive populations followed a y = x

Effects of El Niño-driven changes in wind patterns on North Pacific albatrosses.

Science.gov (United States)

Thorne, L H; Conners, M G; Hazen, E L; Bograd, S J; Antolos, M; Costa, D P; Shaffer, S A

2016-06-01

Changes to patterns of wind and ocean currents are tightly linked to climate change and have important implications for cost of travel and energy budgets in marine vertebrates. We evaluated how El Niño-Southern Oscillation (ENSO)-driven wind patterns affected breeding Laysan and black-footed albatross across a decade of study. Owing to latitudinal variation in wind patterns, wind speed differed between habitat used during incubation and brooding; during La Niña conditions, wind speeds were lower in incubating Laysan (though not black-footed) albatross habitat, but higher in habitats used by brooding albatrosses. Incubating Laysan albatrosses benefited from increased wind speeds during El Niño conditions, showing increased travel speeds and mass gained during foraging trips. However, brooding albatrosses did not benefit from stronger winds during La Niña conditions, instead experiencing stronger cumulative headwinds and a smaller proportion of trips in tailwinds. Increased travel costs during brooding may contribute to the lower reproductive success observed in La Niña conditions. Furthermore, benefits of stronger winds in incubating habitat may explain the higher reproductive success of Laysan albatross during El Niño conditions. Our findings highlight the importance of considering habitat accessibility and cost of travel when evaluating the impacts of climate-driven habitat change on marine predators. © 2016 The Author(s).

Engaging media in communicating research on sexual and reproductive health and rights in sub-Saharan Africa: experiences and lessons learned.

Science.gov (United States)

Oronje, Rose Ndakala; Undie, Chi-Chi; Zulu, Eliya Msiyaphazi; Crichton, Joanna

2011-06-16

The mass media have excellent potential to promote good sexual and reproductive health outcomes, but around the world, media often fail to prioritize sexual and reproductive health and rights issues or report them in an accurate manner. In sub-Saharan Africa media coverage of reproductive health issues is poor due to the weak capacity and motivation for reporting these issues by media practitioners. This paper describes the experiences of the African Population and Health Research Center and its partners in cultivating the interest and building the capacity of the media in evidence-based reporting of reproductive health issues in sub-Saharan Africa. The paper utilizes a case study approach based primarily on the personal experiences and reflections of the authors (who played a central role in developing and implementing the Center's communication and policy engagement strategies), a survey that the Center carried out with science journalists in Kenya, and literature review. The African Population and Health Research Center's media strategy evolved over the years, moving beyond conventional ways of communicating research through the media via news releases and newspaper stories, to varying approaches that sought to inspire and build the capacity of journalists to do evidence-based reporting of reproductive health issues. Specifically, the approach included 1) enhancing journalists' interest in and motivation for reporting on reproductive health issues through training and competitive grants for outstanding reporting ; 2) building the capacity of journalists to report reproductive health research and the capacity of reproductive health researchers to communicate their research to media through training for both parties and providing technical assistance to journalists in obtaining and interpreting evidence; and 3) establishing and maintaining trust and mutual relationships between journalists and researchers through regular informal meetings between journalists and

Genetic variation of male reproductive success in a laboratory population of Anopheles gambiae

Directory of Open Access Journals (Sweden)

Voordouw Maarten J

2007-07-01

Full Text Available Abstract Background For Anopheline mosquitoes, the vectors of human malaria, genetic variation in male reproductive success can have important consequences for any control strategy based on the release of transgenic or sterile males. Methods A quantitative genetics approach was used to test whether there was a genetic component to variation in male reproductive success in a laboratory population of Anopheles gambiae. Swarms of full sibling brothers were mated with a fixed number of females and their reproductive success was measured as (1 proportion of ovipositing females, (2 proportion of ovipositing females that produced larvae, (3 proportion of females that produced larvae, (4 number of eggs laid per female, (5 number of larvae per ovipositing female and (6 number of larvae per female. Results The proportion of ovipositing females (trait 1 and the proportion of ovipositing females that produced larvae (trait 2 differed among full sib families, suggesting a genetic basis of mating success. In contrast, the other measures of male reproductive success showed little variation due to the full sib families, as their variation are probably mostly due to differences among females. While age at emergence and wing length of the males were also heritable, they were not associated with reproductive success. Larger females produced more eggs, but males did not prefer such partners. Conclusion The first study to quantify genetic variation for male reproductive success in A. gambiae found that while the initial stages of male reproduction (i.e. the proportion of ovipositing females and the proportion of ovipositing females that produced larvae had a genetic basis, the overall reproductive success (i.e. the mean number of larvae per female did not.

The effects of oxidative stress on female reproduction: a review

Directory of Open Access Journals (Sweden)

Agarwal Ashok

2012-06-01

Full Text Available Abstract Oxidative stress (OS, a state characterized by an imbalance between pro-oxidant molecules including reactive oxygen and nitrogen species, and antioxidant defenses, has been identified to play a key role in the pathogenesis of subfertility in both males and females. The adverse effects of OS on sperm quality and functions have been well documented. In females, on the other hand, the impact of OS on oocytes and reproductive functions remains unclear. This imbalance between pro-oxidants and antioxidants can lead to a number of reproductive diseases such as endometriosis, polycystic ovary syndrome (PCOS, and unexplained infertility. Pregnancy complications such as spontaneous abortion, recurrent pregnancy loss, and preeclampsia, can also develop in response to OS. Studies have shown that extremes of body weight and lifestyle factors such as cigarette smoking, alcohol use, and recreational drug use can promote excess free radical production, which could affect fertility. Exposures to environmental pollutants are of increasing concern, as they too have been found to trigger oxidative states, possibly contributing to female infertility. This article will review the currently available literature on the roles of reactive species and OS in both normal and abnormal reproductive physiological processes. Antioxidant supplementation may be effective in controlling the production of ROS and continues to be explored as a potential strategy to overcome reproductive disorders associated with infertility. However, investigations conducted to date have been through animal or in vitro studies, which have produced largely conflicting results. The impact of OS on assisted reproductive techniques (ART will be addressed, in addition to the possible benefits of antioxidant supplementation of ART culture media to increase the likelihood for ART success. Future randomized controlled clinical trials on humans are necessary to elucidate the precise mechanisms

Detecting local establishment strategies of wild cherry (Prunus avium L.

Directory of Open Access Journals (Sweden)

Gregorius Hans-Rolf

2006-10-01

Full Text Available Abstract Backround P. avium, a pioneer tree species that colonizes early forest successional stages, is assumed to require an effective strategy allowing stably repeatable rounds of local establishment, dispersal and local extinction. Consequently, the early replacement of cherry by climax tree species makes the establishment of several local generations very unlikely, especially in central European continuous cover forests. This has to be seen in connection with the mixed reproduction system involving asexual reproduction as a complementary adaptational strategy. Tests of the local establishment of wild cherry must therefore consider the possibility of first generation establishment via seedling recruitment potentially followed by an asexual generation (root suckering. Successful establishment can therefore be determined only among adult individuals with the option of detecting vegetative reproduction at these stages. To test the implied suggestion about local establishment strategies of wild cherry, nuclear microsatellites were used to analyse patterns of asexual propagation among adult stages that have been subjected to one of two major types of forest management. These management types, the historical "coppice with standards system" (CWS and the "high forest system" (HFS, can be reasonably assumed to have affected the reproduction system of P. avium. Results Clear differences were found in the reproduction pattern between two stands representing the two forest management types: 1 Clonal propagation is observed in both management systems, but with a distinctly higher frequency in the CWS. Hence, sexual recruitment as a first local generation is followed by a second asexual generation in both, whereas in the CWS there is evidence for an additional clonal generation. 2 The estimation of amounts of clonal reproduction critically depends on the assumptions about multilocus gene associations. This is revealed by the application of newly developed

Source driven breeding thermal power reactors

International Nuclear Information System (INIS)

Greenspan, E.; Schneider, A.; Misulovin, A.; Gilai, D.; Levin, P.; Ben-Gurion Univ. of the Negev, Beersheba

1978-03-01

Improvements in the performance of fission power reactors made possible by designing them subcritical driven by D-T neutron sources are investigated. Light-water thermal systems are found to be most promising, neutronically and energetically, for the source driven mode of operation. The range of performance characteristics expected from breeding Light Water Hybrid Reactors (LWHR) is defined. Several promising types of LWHR blankets are identified. Options opened for the nuclear energy strategy by four types of the LWHRs are examined, and the potential contribution of these LWHRs to the nuclear energy economy are discussed. The power systems based on these LWHRs are found to enable a high utilization of the energy content of the uranium resources in all forms available - including depleted uranium and spent fuel from LWRs, while being free from the need for uranium enrichment and plutonium separation capabilities. (author)

Reproductive strategy of the shrimp Nematopalaemon schmitti (Decapoda, Caridea, Palaemonoidea on the southeastern coast of Brazil

Directory of Open Access Journals (Sweden)

Rafaela Torres Pereira

Full Text Available Abstract The goal of this study was to evaluate the reproductive investment (RI and the fecundity of the shrimp Nematopalaemon schmitti (Holthuis, 1950, caught by trawling in the southeastern Brazilian coast in 2008, 2009 and 2011. The carapace length (CL of ovigerous females was measured and the development stage of their ovaries and embryos were analyzed. A significant relationship was observed between the female body and embryo weights (Linear regression: r² = 0.26, F = 20.77, P < 0.0001, Ln BDW = 0.92. Ln FBDW - 2.24 and between number of embryos and CL (Linear regression; stage I: r² = 0.38, F = 36.15, P < 0.0001; stage II: r² = 0.34, F = 14.10, P < 0.001, but not between the RI and CL (ANOVA: F = 0.47, df = 7, P = 0.85. Association of the changes in embryo development and ovarian maturation of ovigerous females was tested. Females with rudimentary ovaries predominantly showed embryos in stage I (early development and females with developed ovaries only showed embryos in stage II (final development, showing synchrony between the development of both, thus supporting the hypothesis of a continuous reproductive cycle for N. schmitti in the region. Such information is fundamental for understanding the reproductive biology of these crustaceans, as well as other caridean shrimps, in order to promote the maintenance and preservation of natural stocks.

The role of adiponectin in reproduction: from polycystic ovary syndrome to assisted reproduction.

Science.gov (United States)

Michalakis, Konstantinos G; Segars, James H

2010-11-01

To summarize the effects of the adipokine adiponectin on the reproductive endocrine system, from the hypothalamic-pituitary axis to the gonads and target tissues of the reproductive system. A Medline computer search was performed to identify relevant articles. Research institution. None. Adiponectin is a hormone secreted by adipose tissue that acts to reduce insulin resistance and atherogenic damage, but it also exerts actions in other tissues. Adiponectin mediates its actions in the periphery mainly via two receptors, AdipoR1 and AdipoR2. Adiponectin receptors are present in many reproductive tissues, including the central nervous system, ovaries, oviduct, endometrium, and testes. Adiponectin influences gonadotropin release, normal pregnancy, and assisted reproduction outcomes. Adiponectin, a beneficial adipokine, represents a major link between obesity and reproduction. Higher levels of adiponectin are associated with improved menstrual function and better outcomes in assisted reproductive cycles. Published by Elsevier Inc.

Effect of Emamectin Benzoate on Mortality, Proboscis Extension, Gustation and Reproduction of the Corn Earworm, Helicoverpa zea

OpenAIRE

López, Juan D.; Latheef, M. A.; Hoffmann, W. C.

2010-01-01

Newly emerged corn earworm adults, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) require a carbohydrate source from plant or other exudates and nectars for dispersal and reproduction. Adults actively seek and forage at feeding sites upon eclosion in the habitat of the larval host plant or during dispersal to, or colonization of, a suitable reproductive habitat. This nocturnal behavior of H. zea has potential for exploitation as a pest management strategy for suppression using an adult fee...

Conservative litigation against sexual and reproductive health policies in Argentina.

Science.gov (United States)

Peñas Defago, María Angélica; Morán Faúndes, José Manuel

2014-11-01

In Argentina, campaigns for the recognition of sexual and reproductive rights have sparked opposition through litigation in which the dynamics of legal action have come from self-proclaimed "pro-life" NGOs, particularly since 1998, when the conservative NGO Portal de Belén successfully achieved the banning of emergency contraception through the courts. The activities of these groups, acting as a "civil arm" of religion, are focused primarily on obstructing access to legally permissible abortions and bringing about the withdrawal of a number of recognized public policies on sexual and reproductive health, particularly the 2002 National Programme for Sexual Health and Responsible Procreation. This paper analyzes the litigation strategies of these conservative NGOs and how their use of the courts in Argentina has changed over the years. It gives examples of efforts in local courts to block individual young women from accessing legal abortion following rape, despite a ruling by the National Supreme Court of Justice in 2012 that no judicial permission is required. In spite of major advances, the renewed influence of the Catholic hierarchy in the Argentine political scene with the accession of the new Pope poses challenges to the work by feminists and women's movements to extend and consolidate sexual and reproductive rights. Copyright © 2014 Reproductive Health Matters. Published by Elsevier Ltd. All rights reserved.

Reproductive dynamics of Pacific sanddab, Citharichthys sordidus, off the central coast of California

Science.gov (United States)

Lefebvre, Lyndsey S.; Payne, Amber M.; Field, John C.

2016-01-01

Female Pacific sanddab were collected from the Monterey Bay, California to describe their reproductive strategy and annual reproductive cycle, as well as to estimate length at maturity, fecundity, spawning fraction (SF), and spawning interval (SI). Captive females were held to examine degradation of spawning markers and confirmed the biological spawning capabilities of the species. The reproductive season extended from May through January, as determined through macroscopic and histological examination of ovaries. Oocyte development was asynchronous, and an indeterminate fecundity pattern was displayed. Absolute and relative batch fecundity values were variable (means = 6663 eggs and 54 eggs g- 1 somatic weight, respectively) and significantly related to maternal length. During the period of highest reproductive activity, SF ranged from 0.42 to 0.98, suggesting some females were spawning on a daily basis. Monthly SF and SI were related to length, with smaller females having a truncated season and lower SF compared to larger females. Lengths at 50% (119 mm) and 95% (149 mm) maturity showed a downward shift relative to the 1940s, though the magnitude and cause of this shift remain unknown. This study highlights the importance of considering demographic shifts and size-related dynamics when modeling a stock's reproductive potential.

Reproductive effort and the egg number vs. size trade-off in Physalaemus frogs (Anura: Leiuperidae)

Science.gov (United States)

Camargo, Arley; Sarroca, Macarena; Maneyro, Raúl

2008-09-01

Patterns of reproductive allocation are expected to differ between species according to temporally and spatially variable costs of reproduction. Even when reproductive allocation patterns are the same, species can also differ in how the reproductive effort is allocated between offspring number and size. In this study, we compared the reproductive allocation patterns and the offspring number vs. size trade-off in two frog species, Physalaemus biligonigerus and P. gracilis, using bivariate (standardized major axis) and multiple linear regressions. Both species showed a common slope between body size and reproductive effort and thus a similar allocation pattern although P. biligonigerus has a larger body size (shift along common slope) and makes a lower reproductive effort (shift in intercept) than P. gracilis. We suggest that similar allocation patterns may be related to the shared phenologies of these frogs and that the differences in reproductive effort could represent either an adaptive shift (e.g., change in body space for the clutch) or a historical constraint. There was a negative correlation between fecundity and egg size in P. biligonigerus but not in P. gracilis as predicted by the acquisition-allocation model (Y-model). This study constitutes the first valid test of the Y-model based on recent predictions derived for the trade-off between offspring size vs. number. We conclude that future studies should compare reproductive allocation patterns between species using tests of allometric slopes with appropriate phylogenetic control to detect both adaptive shifts in allocation strategies and correlations with other life-history traits.

Ovarian fluid impacts flagellar beating and biomechanical metrics of sperm between alternative reproductive tactics

Czech Academy of Sciences Publication Activity Database

Butts, I. A. E.; Prokopchuk, Galina; Kašpar, V.; Cosson, J.; Pitcher, T. E.

2017-01-01

Roč. 220, č. 12 (2017), s. 2210-2217 ISSN 0022-0949 Institutional support: RVO:60077344 Keywords : competition * salmon * Oncorhynchus tshawytscha * spawning * reproductive strategy * sperm competition * cryptic female choice Subject RIV: EG - Zoology OBOR OECD: Zoology Impact factor: 3.320, year: 2016

Territory and group sizes in Eurasian beavers (Castor fiber): echoes of settlement and reproduction?

NARCIS (Netherlands)

Campbell, R.D.; Rosell, F.; Nolet, B.A.; Dijkstra, V.A.A.

2005-01-01

According to current theories of territoriality, an animal is expected to defend the smallest area that can provide resources for maximisation of reproduction, known as the economically defendable area. In group territorial species however, the strategies behind resource defence are likely to be

Late injury of cancer therapy on the female reproductive tract

International Nuclear Information System (INIS)

Grigsby, Perry W.; Russell, Anthony; Bruner, Deborah; Eifel, Patricia; Koh, Wui-Jin; Spanos, William; Stetz, Joann; Stitt, Judith Anne; Sullivan, Jessie

1995-01-01

The purpose of this article is to review the late effects of cancer therapy on the female reproductive tract. The anatomic sites detailed are the vulva, vagina, cervix, uterus, fallopian tubes, and ovaries. The available pathophysiology is discussed. Clinical syndromes are presented. Tolerance doses of irradiation for late effects are rarely presented in the literature and are reviewed where available. Management strategies for surgical, radiotherapeutic, and chemotherapeutic late effects are discussed. Endpoints for evaluation of therapeutic late effects have been formulated utilizing the symptoms, objective, management, and analytic (SOMA) format. Late effects on the female reproductive tract from cancer therapy should be recognized and managed appropriately. A grading system for these effects is presented. Endpoints for late effects and tolls for the evaluation need to be further developed

Performance-Driven Interface Contract Enforcement for Scientific Components

Energy Technology Data Exchange (ETDEWEB)

Dahlgren, Tamara Lynn [Univ. of California, Davis, CA (United States)

2008-01-01

Performance-driven interface contract enforcement research aims to improve the quality of programs built from plug-and-play scientific components. Interface contracts make the obligations on the caller and all implementations of the specified methods explicit. Runtime contract enforcement is a well-known technique for enhancing testing and debugging. However, checking all of the associated constraints during deployment is generally considered too costly from a performance stand point. Previous solutions enforced subsets of constraints without explicit consideration of their performance implications. Hence, this research measures the impacts of different interface contract sampling strategies and compares results with new techniques driven by execution time estimates. Results from three studies indicate automatically adjusting the level of checking based on performance constraints improves the likelihood of detecting contract violations under certain circumstances. Specifically, performance-driven enforcement is better suited to programs exercising constraints whose costs are at most moderately expensive relative to normal program execution.

Strategies for rearing of rabbit does

NARCIS (Netherlands)

Rommers, J.M.

2003-01-01

This thesis describes the effects of different rearing strategies for young rabbit does on body development and reproduction performance. In current rearing, does are often fed to appetite from weaning to first insemination. First insemination is applied when 75 to 80% of mature body weight (BW) is

Hypothesis driven development of new adjuvants: short peptides as immunomodulators.

Science.gov (United States)

Dong, Jessica C; Kobinger, Gary P

2013-04-01

To date, vaccinations have been one of the key strategies in the prevention and protection against infectious pathogens. Traditional vaccines have well-known limitations such as safety and efficacy issues, which consequently deems it inappropriate for particular populations and may not be an effective strategy against all pathogens. This evidence highlights the need to develop more efficacious vaccination regiments. Higher levels of protection can be achieved by the addition of immunostimulating adjuvants. Many adjuvants elicit strong, undefined inflammation, which produces increased immunogenicity but may also lead to undesirable effects. Hypothesis driven development of adjuvants is needed to achieve a more specific and directed immune response required for optimal and safe vaccine-induced immune protection. An example of such hypothesis driven development includes the use of short immunomodulating peptides as adjuvants. These peptides have the ability to influence the immune response and can be extrapolated for adjuvant use, but requires further investigation.

Dealing with uterine fibroids in reproductive medicine.

Science.gov (United States)

Gambadauro, P

2012-04-01

Women who wish to conceive are nowadays more likely to present with uterine fibroids, mainly because of the delay in childbearing in our society. The relationship between uterine fibroids and human reproduction is still controversial and counselling patients might sometimes be challenging. This paper is to assist those involved in the management of patients of reproductive age presenting with uterine fibroids. The interference of fibroids on fertility largely depends on their location. Submucous fibroids interfere with fertility and should be removed in infertile patients, regardless of the size or the presence of symptoms. Intramural fibroids distorting the cavity reduce the chances of conception, while investigations on intramural fibroids not distorting the cavity have so far given controversial results. No evidence supports the systematic removal of subserosal fibroids in asymptomatic, infertile patients. Myomectomy is still the 'gold standard' in fibroid treatment for fertility-wishing patients. In experienced hands, hysteroscopic myomectomy is minimally invasive, safe, and effective. Abdominal and laparoscopic myomectomy might be challenging, but potential risks could be reduced by new strategies and techniques.

Task Demands in OSCEs Influence Learning Strategies.

Science.gov (United States)

Lafleur, Alexandre; Laflamme, Jonathan; Leppink, Jimmie; Côté, Luc

2017-01-01

Models on pre-assessment learning effects confirmed that task demands stand out among the factors assessors can modify in an assessment to influence learning. However, little is known about which tasks in objective structured clinical examinations (OSCEs) improve students' cognitive and metacognitive processes. Research is needed to support OSCE designs that benefit students' metacognitive strategies when they are studying, reinforcing a hypothesis-driven approach. With that intent, hypothesis-driven physical examination (HDPE) assessments ask students to elicit and interpret findings of the physical exam to reach a diagnosis ("Examine this patient with a painful shoulder to reach a diagnosis"). When studying for HDPE, students will dedicate more time to hypothesis-driven discussions and practice than when studying for a part-task OSCE ("Perform the shoulder exam"). It is expected that the whole-task nature of HDPE will lead to a hypothesis-oriented use of the learning resources, a frequent use of adjustment strategies, and persistence with learning. In a mixed-methods study, 40 medical students were randomly paired and filmed while studying together for two hypothetical OSCE stations. Each 25-min study period began with video cues asking to study for either a part-task OSCE or an HDPE. In a crossover design, sequences were randomized for OSCEs and contents (shoulder or spine). Time-on-task for discussions or practice were categorized as "hypothesis-driven" or "sequence of signs and maneuvers." Content analysis of focus group interviews summarized students' perception of learning resources, adjustment strategies, and persistence with learning. When studying for HDPE, students allocate significantly more time for hypothesis-driven discussions and practice. Students use resources contrasting diagnoses and report persistence with learning. When studying for part-task OSCEs, time-on-task is reversed, spent on rehearsing a sequence of signs and maneuvers. OSCEs with

The functionality of biological knowledge in the workplace. Integrating school and workplace learning about reproduction

NARCIS (Netherlands)

Mazereeuw, M.

2013-01-01

This thesis reports on a design research project about a learning, supervising and teaching strategy to enable students in agricultural preparatory vocational secondary education (VMBO) to recognize the functionality of biological knowledge of reproduction in work placement sites. Although

Different patterns of oviposition learning in two closely related ectoparasitoid wasps with contrasting reproductive strategies

Science.gov (United States)

Sasakawa, Kôji; Uchijima, Kenta; Shibao, Harunobu; Shimada, Masakazu

2013-02-01

Many parasitoid wasps learn host-associated cues and use them in subsequent host-searching behavior. This associative learning, namely "oviposition learning," has been investigated in many studies. However, few studies have compared multiple species, and no comparative study has previously been conducted on ectoparasitoid species. We compared the effects of oviposition learning on host preference and offspring sex ratio in two closely related ectoparasitoid wasps with contrasting reproductive strategies, Anisopteromalus calandrae (r-strategist) and its sibling species (K-strategist). Using two bruchine hosts, Callosobruchus chinensis and Callosobruchus maculatus larvae infesting the cowpea Vigna unguiculata, oviposition choice experiments were performed at high and low host densities. In both species, no conspicuous effect on the offspring sex ratio was detected, but effects on host preference were found to differ between the species. In A. calandrae, the effects were detected only at high host density, suggesting that oviposition learning plays a role in host discrimination from a short distance but not from a long distance. In the sibling species, those effects were not detected in any of the cases, suggesting the absence of oviposition learning. These results are compatible with those of previous comparative studies of endoparasitoid wasps in that few lifetime oviposition experiences and/or low reward per foraging decision result in low or absent oviposition learning ability. This finding may indicate that ecological traits contributing to learning ability are similar between endoparasitoid and ectoparasitoid wasps. Thus, our species comparison of ectoparasitoids provides another model system for investigating learning and memory dynamics in parasitoid wasps.

Female Reproductive System

Science.gov (United States)

... of the Female Reproductive System Print en español Sistema reproductor femenino About Human Reproduction All living things ... of Use Notice of Nondiscrimination Visit the Nemours Web site. Note: All information on KidsHealth® is for ...

Reproductive variability of the Amazon River prawn, Macrobrachium amazonicum (Caridea, Palaemonidae: influence of life cycle on egg production

Directory of Open Access Journals (Sweden)

Andrea L Meireles

2013-09-01

Full Text Available Diverse reproductive strategies may be adopted by different species of Macrobrachium prawns, and even among different populations of the same species. The present study evaluated the influence of differences in the reproductive strategies of two geographically isolated populations of Macrobachium amazonicum, upon female fecundity, reproductive output and the chemical content of prawns and eggs. One prawn population from Pará only completes its life cycle in brackish water, whereas another from Mato Grosso do Sul only inhabits freshwater. Pará female prawns exhibited a larger average size and weight and produced more eggs than females from Mato Grosso do Sul. However, the Mato Grosso do Sul population produced eggs that were larger in volume than those of females from the other population. Furthermore, eggs produced by Pará prawns were composed primarily of water (56%, whereas those produced in Mato Grosso do Sul were composed mostly of organic matter (80%. This difference in the eggs' chemical compositions did not apply to the chemical compositions of the females, as individuals from both sites were composed primarily of water. Mato Grosso do Sul females invested a higher amount of energy in brood formation (14% of their wet weight than individuals from Pará (only 10%. It is possible that M. amazonicum populations show a higher degree of plasticity in their reproductive activity due to habitat conditions and genetic differences. Although the brackish population produces larger individuals, and exhibits higher fecundity, the freshwater population exhibited a higher reproductive investment. These results suggest a high reproductive capacity to adapt to different environmental conditions for this species, which should be considered in the context of aquaculture activities.

Colony Development and Reproductive Success of Bumblebees in an Urban Gradient

Directory of Open Access Journals (Sweden)

Chatura Vaidya

2018-06-01

Full Text Available Approximately 35% of all crop production is dependent on animal-mediated pollination. Many wild bee species are declining rapidly across North America and Europe, a potential consequence of land-use change driven by agricultural intensification and urbanization. In this study we assessed the impact of urbanization on the reproductive success and population growth rate of bumblebees in an urbanization gradient. We placed experimental nests in ten sites; all except one were community gardens, ranging from a 0–99% degree of urbanization. Reproductive success and colony size were positively correlated with cumulative weight gain of the nests (p < 0.05. We did not find an effect of urbanization on the population growth rate of the nests or on forager activity (p > 0.05. Growth rate was strongly negatively affected by the abundance of wax moth larvae (p < 0.05 and positively correlated with parasite diversity (p < 0.05 and the number of foragers entering the nest (p < 0.01. With this study we show that not only bottom-up but also top-down effects are equally important for pollinator population dynamics.

Reproductive parameters of topmouth gudgeon (Pseudorasbora parva) from massively disturbed Cicov ponds habitat

International Nuclear Information System (INIS)

Lonek, L.; Svolikova, K.

2015-01-01

Topmouth gudgeon, which is native to Southeast Asia, is currently categorized as a highly invasive species of fishes. It is able to adapt to conditions in new environments relatively fast, which is probably facilitated by flexible reproductive strategy. In this thesis, reproductive parameters of a population from a heavily disturbed habitat are analysed. Sex ratio, gonadosomatic index, absolute and relative fecundity, as well as the diameter of oocytes were assessed. The sample was collected in post-spawning season (October 2012) and it consisted of 50 specimens. The results are considered to reflect the conditions that prevail in the Cicov ponds, i.e. the heavily disturbed habitat. (authors)

Ten clinician-driven strategies for maximising value of Australian health care.

Science.gov (United States)

Scott, Ian

2014-05-01

To articulate the concept of high-value care (i.e. clinically relevant, patient-important benefit at lowest possible cost) and suggest strategies by which clinicians can promote such care in rendering the Australian healthcare system more affordable and sustainable. Strategies were developed by the author based on personal experience in clinical practice, evidence-based medicine and quality improvement. Relevant literature was reviewed in retrieving studies supporting each strategy. Ten strategies were developed: (1) minimise errors in diagnosis; (2) discontinue low- or no-value practices that provide little benefit or cause harm; (3) defer the use of unproven interventions; (4) select care options according to comparative cost-effectiveness; (5) target clinical interventions to those who derive greatest benefit; (6) adopt a more conservative approach nearing the end of life; (7) actively involve patients in shared decision making and self-management; (8) minimise day-to-day operational waste; (9) convert healthcare institutions into rapidly learning organisations; and (10) advocate for integrated patient care across all clinical settings. Clinicians and their professional organisations, in partnership with managers, can implement strategies capable of maximising value and sustainability of health care in Australia. What is known about this topic? Value-based care has emerged as a unitary concept that integrates quality and cost, and is being increasingly used to inform healthcare policy making and reform. What does this paper add? There is scant literature that translates the concept of high value care into actionable enhancement strategies for clinicians in everyday practice settings. This article provides 10 strategies with supporting studies in an attempt to fill this gap. What are the implications for practitioners? If all practitioners, in partnership with healthcare managers, attempted to enact all 10 strategies in their workplaces, a significant quantum of

VARIATIONS IN REPRODUCTIVE TOXICANT IDENTIFICATION

Energy Technology Data Exchange (ETDEWEB)

Simmons, F

2008-05-13

Reproductive toxicants are a very important class of compounds. They present unique hazards to those of child bearing ages, perform their 'dirty work' using a wide variety of mechanisms on a number of different organs, and are regulatorily important. Because of all of this, properly identifying reproductive toxicants is important, but fraught with difficulty. In this paper we will describe types or reproductive toxicants, their importance, and both mistakes and good practices that people who are not experts in reproductive toxicology may use in their attempts to identify them. Additionally, this paper will focus on chemical reproductive toxicants and will not address biological agents that could affect reproductive toxicity although many principles outlined here could be applied to that endeavor.

Reproductive effort affects oxidative status and stress in an Antarctic penguin species: An experimental study.

Directory of Open Access Journals (Sweden)

Roger Colominas-Ciuró

Full Text Available The oxidative cost of reproduction has been a matter of debate in recent years presumably because of the lack of proper experimental studies. Based on the hypothesis that different brood sizes produce differential reproductive costs, an experimental manipulation during breeding of Adélie penguins was conducted at Hope Bay, Antarctica, to study oxidative status and stress. We predict that a lower reproductive effort should be positively related to low oxidative and physiological stress. We randomly assigned nests with two chicks to a control reproductive effort group (CRE, and by removing one chick from some nests with two chicks, formed a second, low reproductive effort group (LRE. We examined how oxidative status in blood plasma (reactive oxygen metabolites, ROMs, and total antioxidant capacity, OXY and stress (heterophil/lymphocyte ratio, H/L responded to a lower production of offspring total biomass. Our nest manipulation showed significant differences in offspring total biomass, which was lower in the LRE group. As predicted, the LRE group had higher antioxidant capacity than individuals in the CRE group. We have also found, although marginally significant, interactions between sex and treatment in the three variables analysed. Females had higher OXY, lower ROMs and lower H/L ratio when rearing one chick, whereas males did so when rearing two except for OXY which was high regardless of treatment. Moreover, there was a significant negative correlation between the H/L ratio and OXY in females. Finally, we have found a negative and significant relationship between the duration of the experiment and OXY and ROMs and positive with H/L ratio which suggests that indeed breeding penguins are paying an effort in physiological terms in relation to the duration of the chick rearing. In conclusion, a reduction of the reproductive effort decreased oxidative stress in this long-lived bird meaning that a link exists between breeding effort and oxidative

Reproductive effort affects oxidative status and stress in an Antarctic penguin species: An experimental study.

Science.gov (United States)

Colominas-Ciuró, Roger; Santos, Mercedes; Coria, Néstor; Barbosa, Andrés

2017-01-01

The oxidative cost of reproduction has been a matter of debate in recent years presumably because of the lack of proper experimental studies. Based on the hypothesis that different brood sizes produce differential reproductive costs, an experimental manipulation during breeding of Adélie penguins was conducted at Hope Bay, Antarctica, to study oxidative status and stress. We predict that a lower reproductive effort should be positively related to low oxidative and physiological stress. We randomly assigned nests with two chicks to a control reproductive effort group (CRE), and by removing one chick from some nests with two chicks, formed a second, low reproductive effort group (LRE). We examined how oxidative status in blood plasma (reactive oxygen metabolites, ROMs, and total antioxidant capacity, OXY) and stress (heterophil/lymphocyte ratio, H/L) responded to a lower production of offspring total biomass. Our nest manipulation showed significant differences in offspring total biomass, which was lower in the LRE group. As predicted, the LRE group had higher antioxidant capacity than individuals in the CRE group. We have also found, although marginally significant, interactions between sex and treatment in the three variables analysed. Females had higher OXY, lower ROMs and lower H/L ratio when rearing one chick, whereas males did so when rearing two except for OXY which was high regardless of treatment. Moreover, there was a significant negative correlation between the H/L ratio and OXY in females. Finally, we have found a negative and significant relationship between the duration of the experiment and OXY and ROMs and positive with H/L ratio which suggests that indeed breeding penguins are paying an effort in physiological terms in relation to the duration of the chick rearing. In conclusion, a reduction of the reproductive effort decreased oxidative stress in this long-lived bird meaning that a link exists between breeding effort and oxidative stress. However

Reproductive hazards in the workplace: what the practitioner needs to know about chemical exposures.

Science.gov (United States)

Paul, M; Himmelstein, J

1988-06-01

A growing body of scientific evidence implicates occupational chemical exposures in the etiology of human adverse reproductive outcomes. Most reproductive toxins that have been investigated in sufficient detail have been shown to exert multiple effects on and through both men and women. In the face of growing public awareness, it is essential that clinicians develop a knowledgeable and effective approach to patient concerns about reproductive hazards in the workplace. Of vital importance is the accurate characterization of exposure at the worksite. Intervention strategies for worrisome situations include amelioration of worksite exposure or, as a last resort, temporary, compensated job modification or transfer. The clinician can obtain assistance in addressing the problem from several resources, including local regulatory agencies and occupational health clinics. Widespread involvement of knowledgeable health professionals can have a dramatic impact on improving this important contemporary public health problem.

Fast Mechanically Driven Daughter Cell Separation Is Widespread in Actinobacteria.

Science.gov (United States)

Zhou, Xiaoxue; Halladin, David K; Theriot, Julie A

2016-08-30

Dividing cells of the coccoid Gram-positive bacterium Staphylococcus aureus undergo extremely rapid (millisecond) daughter cell separation (DCS) driven by mechanical crack propagation, a strategy that is very distinct from the gradual, enzymatically driven cell wall remodeling process that has been well described in several rod-shaped model bacteria. To determine if other bacteria, especially those in the same phylum (Firmicutes) or with similar coccoid shapes as S. aureus, might use a similar mechanically driven strategy for DCS, we used high-resolution video microscopy to examine cytokinesis in a phylogenetically wide range of species with various cell shapes and sizes. We found that fast mechanically driven DCS is rather rare in the Firmicutes (low G+C Gram positives), observed only in Staphylococcus and its closest coccoid relatives in the Macrococcus genus, and we did not observe this division strategy among the Gram-negative Proteobacteria In contrast, several members of the high-G+C Gram-positive phylum Actinobacteria (Micrococcus luteus, Brachybacterium faecium, Corynebacterium glutamicum, and Mycobacterium smegmatis) with diverse shapes ranging from coccoid to rod all undergo fast mechanical DCS during cell division. Most intriguingly, similar fast mechanical DCS was also observed during the sporulation of the actinobacterium Streptomyces venezuelae Much of our knowledge on bacterial cytokinesis comes from studying rod-shaped model organisms such as Escherichia coli and Bacillus subtilis Less is known about variations in this process among different bacterial species. While cell division in many bacteria has been characterized to some extent genetically or biochemically, few species have been examined using video microscopy to uncover the kinetics of cytokinesis and daughter cell separation (DCS). In this work, we found that fast (millisecond) DCS is exhibited by species in two independent clades of Gram-positive bacteria and is particularly prevalent

Market driven strategy for acquisition of waste acceptance and transportation services for commercial spent fuel in the united states

International Nuclear Information System (INIS)

Lemeshewsky, W.; Macaluso, C.; Smith, P.; Teer, B.

1998-01-01

The Office of Civilian Radioactive Waste Management (OCRWM) in the United States Department of Energy (DOE) has the responsibility under the Nuclear Waste Policy Act of 1982 (the Act) for the shipment of spent nuclear fuel (SNF) from commercial reactors to a Federal facility for storage and/or disposal. The Act requires the use of private industry to the 'fullest extent possible' in the transportation of spent fuels. An OCRWM goal is to develop a safe, efficient and effective transportation system while meeting the mandate of the Act. OCRWM has then develop a strategy for a market driven approach for the acquisition of transportation services and equipment. To implement this strategy, OCRWM is planning to issue a Request for Proposal (RPF) for the provision of the required services and equipment to accept SNF from the utilities and transport the SNF to a Federal facility. Two draft RPFs have been issued with the second draft incorporating comments on the first draft from potential contractors and other interested parties. The overall strategy as outlined in the draft RPF relies on private industry to use the innovative powers of the marketplace to help DOE accomplish its mission objectives. DOE intends to pursue this procurement strategy whether or not the OCRWM program includes interim storage. The concept described in the draft RPF provides for DOE to purchase services and equipment from a contractor-operated waste acceptance and transportation organization. The contractor is expected to provide initial financing for the project including that necessary for initial acquisition of operational equipment, establish the necessary management organization, and mobilize the necessary resources and capabilities to provide the SNF delivery services at a fixed rate. DOE will retain final approval on all routes and maintain primary responsibility to the States, tribes, and local units of government for assuring appropriate interaction and consideration of their input on

Mast fruiting is a frequent strategy in woody species of eastern South America.

Directory of Open Access Journals (Sweden)

Natalia Norden

Full Text Available BACKGROUND: It is thought that mast seeding is a rare reproductive strategy in the tropics, since tropical climates are less variable, and fruit consumers tend to be more generalist in these regions. However, previous tests of this hypothesis were based on only few tropical datasets, and none from tropical South America. Moreover, reproductive strategies have been quantified based on the coefficient of variation of interannual seed production, an index that potentially confounds masting and high interannual variability in seed production. METHODOLOGY/PRINCIPAL FINDINGS: We developed a new approach to model the monthly variability in seed production for 28 tree species, and 20 liana species monitored during 5 years in a tropical forest of Central French Guiana. We found that 23% of the species showed a masting pattern, 54% an annual fruiting pattern, and 23% an irregular fruiting pattern. The majority of masting species were trees (8 out of 11, most of them animal-dispersed. The classification into reproductive strategies based on the coefficient of variation was inconsistent with our results in nearly half of the cases. CONCLUSIONS/SIGNIFICANCE: Our study is the first to clearly evidence the frequency of the masting strategy in a tropical forest community of Eastern South America. The commonness of the masting strategy in tropical plants may promote species coexistence through storage dynamics.

Assisted Reproduction: What factors interfere in the professional's decisions? Are single women an issue?

Science.gov (United States)

2011-01-01

Background With the development of medical technology, many countries around the world have been implementing ethical guidelines and laws regarding Medically Assisted Reproduction (MAR). A physician's reproductive decisions are not solely based on technical criteria but are also influenced by society values. Therefore, the aim of this study was to analyze the factors prioritized by MAR professionals when deciding on whether to accept to perform assisted reproduction and to show any existing cultural differences. Methods Cross-sectional study involving 224 healthcare professionals working with assisted reproduction in Brazil, Italy, Germany and Greece. Instrument used for data collection: a questionnaire, followed by the description of four special MAR cases (a single woman, a lesbian couple, an HIV discordant couple and gender selection) which included case-specific questions regarding the professionals' decision on whether to perform the requested procedure as well as the following factors: socio-demographic variables, moral and legal values as well as the technical aspects which influence decision-making. Results Only the case involving a single woman who wishes to have a child (without the intention of having a partner in the future) demonstrated significant differences. Therefore, the study was driven towards the results of this case specifically. The analyses we performed demonstrated that professionals holding a Master's Degree, those younger in age, female professionals, those having worked for less time in reproduction, those in private clinics and Brazilian health professionals all had a greater tendency to perform the procedure in that case. A multivariate analysis demonstrated that the reasons for the professional's decision to perform the procedure were the woman's right to gestate and the duty of MAR professionals to help her. The professionals who decided not to perform the procedure identified the woman's marital status and the child's right to a

Assisted reproduction: what factors interfere in the professional's decisions? Are single women an issue?

Science.gov (United States)

Záchia, Suzana; Knauth, Daniela; Goldim, José R; Chachamovich, Juliana R; Chachamovich, Eduardo; Paz, Ana H; Felberbaum, Ricardo; Crosignani, PierGiorgio; Tarlatzis, Basil C; Passos, Eduardo P

2011-05-31

With the development of medical technology, many countries around the world have been implementing ethical guidelines and laws regarding Medically Assisted Reproduction (MAR). A physician's reproductive decisions are not solely based on technical criteria but are also influenced by society values. Therefore, the aim of this study was to analyze the factors prioritized by MAR professionals when deciding on whether to accept to perform assisted reproduction and to show any existing cultural differences. Cross-sectional study involving 224 healthcare professionals working with assisted reproduction in Brazil, Italy, Germany and Greece. Instrument used for data collection: a questionnaire, followed by the description of four special MAR cases (a single woman, a lesbian couple, an HIV discordant couple and gender selection) which included case-specific questions regarding the professionals' decision on whether to perform the requested procedure as well as the following factors: socio-demographic variables, moral and legal values as well as the technical aspects which influence decision-making. Only the case involving a single woman who wishes to have a child (without the intention of having a partner in the future) demonstrated significant differences. Therefore, the study was driven towards the results of this case specifically. The analyses we performed demonstrated that professionals holding a Master's Degree, those younger in age, female professionals, those having worked for less time in reproduction, those in private clinics and Brazilian health professionals all had a greater tendency to perform the procedure in that case. A multivariate analysis demonstrated that the reasons for the professional's decision to perform the procedure were the woman's right to gestate and the duty of MAR professionals to help her. The professionals who decided not to perform the procedure identified the woman's marital status and the child's right to a father as the reason to

Islamic logics, reproductive rationalities: family planning in northern Pakistan.

Science.gov (United States)

Varley, Emma

2012-01-01

This paper explores the use of Islamic doctrine and jurisprudence by family planning organizations in the Gilgit-Baltistan region of northern Pakistan. It examines how particular interpretations of Islam are promoted in order to encourage fertility reductions, and the ways Muslim clerics, women and their families react to this process. The paper first discusses how Pakistan's demographic crisis, as the world's sixth most populous nation, has been widely blamed on under-funding for reproductive health services and wavering political commitment to family planning. Critics have called for innovative policy and programming to counter 'excessive reproduction' by also addressing socio-cultural and religious barriers to contraceptive uptake. Drawing on two years of ethnographic research, the paper examines how family planning organizations in Gilgit-Baltistan respond to this shift by employing moderate interpretations of Islam that qualify contraceptive use as a 'rational' reproductive strategy and larger families as 'irrational'. However, the use of Islamic rhetoric to enhance women's health-seeking agency and enable fertility reductions is challenged by conservative Sunni ulema (clergy), who seek to reassert collective control over women's bodies and fertility by deploying Islamic doctrine that honors frequent childbearing. Sunnis' minority status and the losses incurred by regional Shia-Sunni conflicts have further strengthened clerics' pronatalist campaigns. The paper then analyses how Sunni women navigate the multiple reproductive rationalities espoused by 'Islamized' family planning and conservative ulema. Although Islamized family planning legitimizes contraceptive use and facilitates many women's stated desire for smaller families, it frequently positions women against the interests of family, community and conservative Islam.

Force Reproduction Error Depends on Force Level, whereas the Position Reproduction Error Does Not

NARCIS (Netherlands)

Onneweer, B.; Mugge, W.; Schouten, Alfred Christiaan

2016-01-01

When reproducing a previously perceived force or position humans make systematic errors. This study determined the effect of force level on force and position reproduction, when both target and reproduction force are self-generated with the same hand. Subjects performed force reproduction tasks at

Gonadossomatic relation and reproductive strategy of Brycon opalinus (Cuvier, 1819 in the Serra do Mar State Park - Núcleo Santa Virgínia, Atlantic Forest, Brazil

Directory of Open Access Journals (Sweden)

LM Gomiero

Full Text Available The objective of this study was to analyze the gonadossomatic relation of males and females of Brycon opalinus (the Pirapitinga do Sul in the Serra do Mar State Park-Núcleo Santa Virgínia. The study area included three rivers: Paraibuna, Ipiranga, and Grande. From the gonadossomatic relation, it was possible to determine the reproductive season and strategy of this species. The gonadossomatic relation was high throughout the year for both males and females. Sperm competition and dilution of the ejaculate in the spawning locations favored substantial development of the testicles. The sex ratio of Brycon opalinus was always in favor of females. The existence of sexual dimorphism in this species was confirmed from the larger size of the females.

The Value of a Well-Being Improvement Strategy: Longitudinal Success across Subjective and Objective Measures Observed in a Firm Adopting a Consumer-Driven Health Plan.

Science.gov (United States)

Guo, Xiaobo; Coberley, Carter; Pope, James E; Wells, Aaron

2015-10-01

The objective of this study is to evaluate effectiveness of a firm's 5-year strategy toward improving well-being while lowering health care costs amidst adoption of a Consumer-Driven Health Plan. Repeated measures statistical models were employed to test and quantify association between key demographic factors, employment type, year, individual well-being, and outcomes of health care costs, obesity, smoking, absence, and performance. Average individual well-being trended upward by 13.5% over 5 years, monthly allowed amount health care costs declined 5.2% on average per person per year, and obesity and smoking rates declined by 4.8 and 9.7%, respectively, on average each year. The results show that individual well-being was significantly associated with each outcome and in the expected direction. The firm's strategy was successful in driving statistically significant, longitudinal well-being, biometric and productivity improvements, and health care cost reduction.

Event driven adaptation, land use and human coping strategies

DEFF Research Database (Denmark)

Reenberg, Anette; Birch-Thomsen, Torben; Fog, Bjarne

perceive cause-effect relationships between societal and environmental events and their individual and collective management of resources. The coupled human-environment timelines are used to discuss ways in which the local communities' adaptive resource management strategies have been employed in the face......The paper focuses on assessing the wider perspectives of adaptive resource management strategies in former subsistence agriculture societies in the SW Pacific. Firstly, we will briefly introduce the theoretical context related to the livelihood framework, adaptation to socio-environmental change...... and the concept of coupled human-environmental timelines. Secondly, with point of departure in a baseline characterization of Bellona Island derived from a comprehensive survey in the late 1960s and resent fieldwork in late 2006, we present the case of Bellona Island. Key issues addressed concern climatic events...

Reproduction cycles and strategies of the cold-water sponges Halisarca dujardini (Demospongiae, Halisarcida), Myxilla incrustans and Iophon piceus (Demospongiae, Poecilosclerida) from the White Sea.

Science.gov (United States)

Ereskovsky, A V

2000-02-01

The reproductive development of the Demospongiae species Halisarca dujardini (Halisarcida), Myxilla incrustans and Iophon piceus (Poecilosclerida) from Chupa Inlet (Kandalaksha Bay, the White Sea) was studied histologically during 1982-1994 and 1997. These species are all viviparous. Halisarca dujardini inhabits shallow waters (1.5-5 m); M. incrustans and I. piceus are common in a more stable environment at depths between 15 and 25 m. Initiation of sexual reproduction stages is dependent upon water temperature. Reproductive effort is low in Myxilla incrustans and I. piceus (reproductive elements contribute 7.3% and 12% of maternal tissue volume respectively), but much higher in H. dujardini (up to 69% of the parental tissue volume). Reproduction leads to localized destruction of maternal tissue for M. incrustans and I. piceus and complete disorder of central and basal parts of the choanosoma of H. dujardini after each period of reproduction. Myxilla incrustans and I. piceus reproduce throughout the hydrological summer, but reproduction in H. dujardini is restricted to 3 weeks. The average life span of M. incrustans and I. piceus is more than 4 years, and that of H. dujardini is about 7-12 months. The data suggest that M. incrustans and I. piceus are K-strategists, whereas H. dujardini is an r-strategist.

Reproduction in females bufalinas: artificial insemination and assisted reproduction

International Nuclear Information System (INIS)

Vale, William G.

2011-01-01

Reproductive behavior in females bufalinas has been studied for the detection of estrus. A system that works through radio telemetry has been developed and proposed to replace the daily visual observation to determine the estrous phase with efficiency and precision. The method used is the fixation on the back of the female with a sensor that emits radio waves every time suffer a pressure exerted by the mountain. Waves have been captured by an antenna and sent to a computer system. The knowledge that has been developed on the management and use of reproductive biotechnologies of reproduction in buffalo, have enabled the technicians and breeders evaluate and indicate which procedures can be used successfully, and increase the application of the fixed-time artificial insemination during the year [es

Land inheritance establishes sibling competition for marriage and reproduction in rural Ethiopia.

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Gibson, Mhairi A; Gurmu, Eshetu

2011-02-08

Intergenerational transfer of wealth has been proposed as playing a pivotal role in the evolution of human sibling relationships. Sibling rivalry is assumed to be more marked when offspring compete for limited heritable resources, which are crucial for reproductive success (e.g., land and livestock); whereas in the absence of heritable wealth, related siblings may cooperate. To date, comparative studies undertaken to support this evolutionary assumption have been confounded by other socioecological factors, which vary across populations, e.g., food sharing and intergroup conflict. In this article we explore effects of sibling competition and cooperation for agricultural resources, marriage, and reproduction in one contemporary Ethiopian agropastoralist society. Here recent changes in land tenure policy, altering transfers of land from parents to offspring, present a unique framework to test the importance of intergenerational transfers of wealth in driving sibling competition, while controlling for socioeconomic biases. In households where land is inherited, the number of elder brothers reduces a man's agricultural productivity, marriage, and reproductive success, as resources diminish and competition increases with each additional sibling. Where land is not inherited (for males receiving land directly from the government and all females) older siblings do not have a competitive effect and in some instances may be beneficial. This study has wider implications for the evolution of human family sizes. Recent changes in wealth transfers, which have driven sibling competition, may be contributing to an increased desire for smaller family sizes.

Profile-driven regression for modeling and runtime optimization of mobile networks

DEFF Research Database (Denmark)

McClary, Dan; Syrotiuk, Violet; Kulahci, Murat

2010-01-01

Computer networks often display nonlinear behavior when examined over a wide range of operating conditions. There are few strategies available for modeling such behavior and optimizing such systems as they run. Profile-driven regression is developed and applied to modeling and runtime optimization...... of throughput in a mobile ad hoc network, a self-organizing collection of mobile wireless nodes without any fixed infrastructure. The intermediate models generated in profile-driven regression are used to fit an overall model of throughput, and are also used to optimize controllable factors at runtime. Unlike...

Grandparental investment: The influence of reproductive timing and family size.

Science.gov (United States)

Coall, David A; Meier, Marc; Hertwig, Ralph; Wänke, Michaela; Höpflinger, François

2009-01-01

The influence that grandparents have on the life history traits of their descendants has been studied extensively. However, no attention has been paid to the potential influence a grandparent's own reproductive history has on the investment they make in their grandchildren. We use data from 658 Swiss grandchildren and 591 of their grandparents to investigate whether grandparents' reproductive scheduling and family size influence the amount of investment grandparents make in a focal grandchild (shared contacts, occasions to meet, activities, discussions, interests, and important roles the grandparent plays). Grandparents who were younger when they had their first child had more children and grandchildren; this relationship strengthened after controlling for grandparental age, sex, lineage, and education (all P children or grandchildren was associated with reduced levels of grandparental investment. After adjustment for a wide range of factors known to influence investment, having more children or grandchildren and having a first child or grandchild at a younger age were associated with reduced investment in 14 of 24 analyses (all P family size. Interestingly, these relationships were only present in data reported from the grandchild's point of view, not the grandparent's. This analysis provides preliminary evidence that grandparents' reproductive strategies have consequences for the amount of investment they make in their grandchildren. These results are examined in terms of the trade-offs between current and future reproduction and offspring quality and quantity. 2009 Wiley-Liss, Inc.

Progeny reproduction

International Nuclear Information System (INIS)

Mashneva, N.I.

1984-01-01

Studies on clarification of importance of different harmful factors of radiation and chemical nature on the function of progeny reproduction, growth and development are presented. Intake of radionuclides to organism, of white mices and rats in concentrations corresponding to 10 6 PCsub(s) ( 90 Sr, 210 Po, 210 Pb and other) is shown to result in 100% sterility of females, 10 5 -10 4 PCsub(s) concentrations cause damaging effect of different degrees of expression at later stages of effect. Smaller contents of radionuclides (10 3 -10 2 PCsub(s)) did not result in noticeable changes in reproductivity of animals. Similar regularities were observed under effect of different concentrations of chemical agent. Some peculiarities of animal physiology should be taken into account to obtain data of estimation of damaging effect of harmful factors on reproduction function

Evolution of premating reproductive isolation among conspecific populations of the sea rock-pool beetle Ochthebius urbanelliae driven by reinforcing natural selection.

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Porretta, Daniele; Urbanelli, Sandra

2012-04-01

How natural selection might be involved in speciation remains a fundamental question in evolutionary biology. When two or more species co-occur in the same areas, natural selection may favor divergence in mating traits. By acting in sympatric but not allopatric populations, natural selection can also affect mate choice within species and ultimately initiate speciation among conspecific populations. Here, we address this potential effect in the sea rock-pool beetles Ochthebius quadricollis and O. urbanelliae. The two species, which inhabit the Mediterranean coasts, co-occurr syntopically in an area along the Italian Tyrrhenian coast and completed reproductive isolation by reinforcement. In this article, through mating trials under laboratory conditions between conspecific populations, we found in O. quadricollis no deviations from random mating. Conversely, in O. urbanelliae, we found a clear pattern of premating isolation between the reinforced populations sympatric with O. quadricollis and those nonreinforced allopatric. This pattern is consistent with the view that natural selection, which completed the reproductive isolation between the two species in sympatry, led incidentally also to partial premating reproductive isolation (I(PSI) estimator from 0.683 to 0.792) between conspecific populations of O. urbanelliae. This case study supports an until recently underappreciated role of natural selection resulting from species interactions in initiating speciation. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

Evolution and Adaptation in Pseudomonas aeruginosa Biofilms Driven by Mismatch Repair System-Deficient Mutators

DEFF Research Database (Denmark)

Luján, Adela M.; Maciá, María D.; Yang, Liang

2011-01-01

, which are rarely eradicated despite intensive antibiotic therapy. Current knowledge indicates that three major adaptive strategies, biofilm development, phenotypic diversification, and mutator phenotypes [driven by a defective mismatch repair system (MRS)], play important roles in P. aeruginosa chronic...... infections, but the relationship between these strategies is still poorly understood. We have used the flow-cell biofilm model system to investigate the impact of the mutS associated mutator phenotype on development, dynamics, diversification and adaptation of P. aeruginosa biofilms. Through competition...... diversification, evidenced by biofilm architecture features and by a wider range and proportion of morphotypic colony variants, respectively. Additionally, morphotypic variants generated in mutator biofilms showed increased competitiveness, providing further evidence for mutator-driven adaptive evolution...

Female Reproductive System (For Teens)

Science.gov (United States)

... of the Female Reproductive System Print en español Sistema reproductor femenino Reproduction All living things reproduce. Reproduction — ... of Use Notice of Nondiscrimination Visit the Nemours Web site. Note: All information on TeensHealth® is for ...

You can go your own way: effectiveness of participant-driven versus experimenter-driven processing strategies in memory training and transfer.

Science.gov (United States)

Flegal, Kristin E; Lustig, Cindy

2016-07-01

Cognitive training programs that instruct specific strategies frequently show limited transfer. Open-ended approaches can achieve greater transfer, but may fail to benefit many older adults due to age deficits in self-initiated processing. We examined whether a compromise that encourages effort at encoding without an experimenter-prescribed strategy might yield better results. Older adults completed memory training under conditions that either (1) mandated a specific strategy to increase deep, associative encoding, (2) attempted to suppress such encoding by mandating rote rehearsal, or (3) encouraged time and effort toward encoding but allowed for strategy choice. The experimenter-enforced associative encoding strategy succeeded in creating integrated representations of studied items, but training-task progress was related to pre-existing ability. Independent of condition assignment, self-reported deep encoding was associated with positive training and transfer effects, suggesting that the most beneficial outcomes occur when environmental support guiding effort is provided but participants generate their own strategies.

You can go your own way: Effectiveness of participant-driven versus experimenter-driven processing strategies in memory training and transfer

Science.gov (United States)

Flegal, Kristin E.; Lustig, Cindy

2016-01-01

Cognitive training programs that instruct specific strategies frequently show limited transfer. Open-ended approaches can achieve greater transfer, but may fail to benefit many older adults due to age deficits in self-initiated processing. We examined whether a compromise that encourages effort at encoding without an experimenter-prescribed strategy might yield better results. Older adults completed memory training under conditions that either 1) mandated a specific strategy to increase deep, associative encoding, 2) attempted to suppress such encoding by mandating rote rehearsal, or 3) encouraged time and effort towards encoding but allowed for strategy choice. The experimenter-enforced associative encoding strategy succeeded in creating integrated representations of studied items, but training-task progress was related to pre-existing ability. Independent of condition assignment, self-reported deep encoding was associated with positive training and transfer effects, suggesting that the most beneficial outcomes occur when environmental support guiding effort is provided but participants generate their own strategies. PMID:26549616

An empirical test of evolutionary theories for reproductive senescence and reproductive effort in the garter snake Thamnophis elegans.

Science.gov (United States)

Sparkman, Amanda M; Arnold, Stevan J; Bronikowski, Anne M

2007-04-07

Evolutionary theory predicts that differential reproductive effort and rate of reproductive senescence will evolve under different rates of external mortality. We examine the evolutionary divergence of age-specific reproduction in two life-history ecotypes of the western terrestrial garter snake, Thamnophis elegans. We test for the signature of reproductive senescence (decreasing fecundity with age) and increasing reproductive effort with age (increasing reproductive productivity per gram female) in replicate populations of two life-history ecotypes: snakes that grow fast, mature young and have shorter lifespans, and snakes that grow slow, mature late and have long lives. The difference between life-history ecotypes is due to genetic divergence in growth rate. We find (i) reproductive success (live litter mass) increases with age in both ecotypes, but does so more rapidly in the fast-growth ecotype, (ii) reproductive failure increases with age in both ecotypes, but the proportion of reproductive failure to total reproductive output remains invariant, and (iii) reproductive effort remains constant in fast-growth individuals with age, but declines in slow-growth individuals. This illustration of increasing fecundity with age, even at the latest ages, deviates from standard expectations for reproductive senescence, as does the lack of increases in reproductive effort. We discuss our findings in light of recent theories regarding the phenomenon of increased reproduction throughout life in organisms with indeterminate growth and its potential to offset theoretical expectations for the ubiquity of senescence.

Altruism and Reproductive Limitations

Directory of Open Access Journals (Sweden)

Carey J. Fitzgerald

2009-04-01

Full Text Available We examined how different types of reproductive limitations — functional (schizoid personality disorder and schizophrenia, physical (malnutrition, and sexual (bisexuality and homosexuality — influenced altruistic intentions toward hypothetical target individuals of differing degrees of relatedness (r = 0, .25, and .50. Participants were 312 undergraduate students who completed a questionnaire on altruism toward hypothetical friends, half-siblings, and siblings with these different types of reproductive limitations. Genetic relatedness and reproductive limitations did not influence altruistic decision-making when the cost of altruism was low but did as the cost of altruism increased, with participants being more likely to help a sibling over a half-sibling and a half-sibling over a friend. Participants also indicated they were more likely to help a healthy (control person over people with a reproductive limitation. Of the three types of reproductive limitations, functional limitations had the strongest effect on altruistic decision-making, indicating that people were less likely to help those who exhibit abnormal social behavior.

Franchising reproductive health services.

Science.gov (United States)

Stephenson, Rob; Tsui, Amy Ong; Sulzbach, Sara; Bardsley, Phil; Bekele, Getachew; Giday, Tilahun; Ahmed, Rehana; Gopalkrishnan, Gopi; Feyesitan, Bamikale

2004-12-01

Networks of franchised health establishments, providing a standardized set of services, are being implemented in developing countries. This article examines associations between franchise membership and family planning and reproductive health outcomes for both the member provider and the client. Regression models are fitted examining associations between franchise membership and family planning and reproductive health outcomes at the service provider and client levels in three settings. Franchising has a positive association with both general and family planning client volumes, and the number of family planning brands available. Similar associations with franchise membership are not found for reproductive health service outcomes. In some settings, client satisfaction is higher at franchised than other types of health establishments, although the association between franchise membership and client outcomes varies across the settings. Franchise membership has apparent benefits for both the provider and the client, providing an opportunity to expand access to reproductive health services, although greater attention is needed to shift the focus from family planning to a broader reproductive health context.

Strategy evolution driven by switching probabilities in structured multi-agent systems

Science.gov (United States)

Zhang, Jianlei; Chen, Zengqiang; Li, Zhiqi

2017-10-01

Evolutionary mechanism driving the commonly seen cooperation among unrelated individuals is puzzling. Related models for evolutionary games on graphs traditionally assume that players imitate their successful neighbours with higher benefits. Notably, an implicit assumption here is that players are always able to acquire the required pay-off information. To relax this restrictive assumption, a contact-based model has been proposed, where switching probabilities between strategies drive the strategy evolution. However, the explicit and quantified relation between a player's switching probability for her strategies and the number of her neighbours remains unknown. This is especially a key point in heterogeneously structured system, where players may differ in the numbers of their neighbours. Focusing on this, here we present an augmented model by introducing an attenuation coefficient and evaluate its influence on the evolution dynamics. Results show that the individual influence on others is negatively correlated with the contact numbers specified by the network topologies. Results further provide the conditions under which the coexisting strategies can be calculated analytically.

Coping Strategies of young mothers at risk of HIV/AIDS in the ...

African Journals Online (AJOL)

Coping Strategies of young mothers at risk of HIV/AIDS in the Kassena-Nankana District of Northern Ghana. ... African Journal of Reproductive Health ... This qualitative study draws on interpretative principles with emphasis on understanding young mothers' vulnerability to HIV/AIDS and explores coping strategies used to ...

Extraterrestrials and Generic Social Processes: Minimizing Resistance in Teaching the Reproduction of Inequality

Science.gov (United States)

Parrotta, Kylie L.; Rusche, Sarah Nell

2011-01-01

In this article, the authors describe a class activity that uses a combination of strategies to overcome obstacles students face when learning about the reproduction of inequality in everyday life. Based on Schwalbe et al.'s (2000) piece on "generic social processes," and following the idea of "making the strange familiar and the familiar…

Reproduction of a fish assemblage in the state of São Paulo, southeastern Brazil

Directory of Open Access Journals (Sweden)

LM. Gomiero

Full Text Available Fish reproductions were studied in two river basins (Corumbataí and Jacaré-Pepira basins in the State of São Paulo, southeastern Brazil. In the Corumbataí basin, four sites were sampled: Cabeça River, Lapa Stream, Passa-Cinco River, and Corumbataí River; in the Jacaré-Pepira basin, three sites were sampled: Tamanduá Stream, Jacaré-Pepira River, and Água Branca Stream. A total of 12 bimonthly samples were made. Fish equipment included gill nets, purse seines, sieves, and traps. The main objective of this study was to characterize the fish assemblage regarding their reproductive biology and to compare these reproductive traits between both river basins. Most individuals with gonads in stage C (mature and in stage D (empty gonads were captured in the spring and summer. Multiple spawn and parental care were common strategies, which guaranteed offspring survivorship in unstable conditions.

Decomposing variation in male reproductive success: age-specific variances and covariances through extra-pair and within-pair reproduction.

Science.gov (United States)

Lebigre, Christophe; Arcese, Peter; Reid, Jane M

2013-07-01

Age-specific variances and covariances in reproductive success shape the total variance in lifetime reproductive success (LRS), age-specific opportunities for selection, and population demographic variance and effective size. Age-specific (co)variances in reproductive success achieved through different reproductive routes must therefore be quantified to predict population, phenotypic and evolutionary dynamics in age-structured populations. While numerous studies have quantified age-specific variation in mean reproductive success, age-specific variances and covariances in reproductive success, and the contributions of different reproductive routes to these (co)variances, have not been comprehensively quantified in natural populations. We applied 'additive' and 'independent' methods of variance decomposition to complete data describing apparent (social) and realised (genetic) age-specific reproductive success across 11 cohorts of socially monogamous but genetically polygynandrous song sparrows (Melospiza melodia). We thereby quantified age-specific (co)variances in male within-pair and extra-pair reproductive success (WPRS and EPRS) and the contributions of these (co)variances to the total variances in age-specific reproductive success and LRS. 'Additive' decomposition showed that within-age and among-age (co)variances in WPRS across males aged 2-4 years contributed most to the total variance in LRS. Age-specific (co)variances in EPRS contributed relatively little. However, extra-pair reproduction altered age-specific variances in reproductive success relative to the social mating system, and hence altered the relative contributions of age-specific reproductive success to the total variance in LRS. 'Independent' decomposition showed that the (co)variances in age-specific WPRS, EPRS and total reproductive success, and the resulting opportunities for selection, varied substantially across males that survived to each age. Furthermore, extra-pair reproduction increased

Reproductive health in women with serious mental illnesses.

Science.gov (United States)

Ozcan, Neslihan Keser; Boyacıoğlu, Nur E; Enginkaya, Semra; Dinç, Hüsniye; Bilgin, Hülya

2014-05-01

To determine what problems female psychiatric patients have in terms of reproductive health. The reproductive health problems faced by female psychiatric patients are matters that have been neglected in the areas of both psychiatry and women's health. This study aims to make a contribution from Turkey to the literature in this neglected field. The study is descriptive and was conducted with 292 female patients treated in an acute inpatient psychiatric ward. Data were collected through face-to-face interviews and a questionnaire based on the literature and prepared by the researchers which was designed to determine the kinds of reproductive health issues the patients were experiencing. It was found that compared with healthy women, the distinctive features of the participants in terms of sexuality were more negative; in particular, patients diagnosed with bipolar disorder were more likely to have been forced by their partners to have sex, they had suffered from rape or sexually transmitted diseases, the majority of those who had previous sexual experience had tried to use contraceptives but had been unable to continue using them, they were most likely to choose the method of withdrawal for contraception, their rates of pregnancy and abortion were high, they received less antenatal care, and they were more likely to have smoked during pregnancy. It was found that female patients with psychiatric disorders had more negative attributes with regard to marriage, sexuality, family planning, maternal characteristics and pregnancy, compared with a corresponding healthy population. The results of this study may be useful for nurses in the clinical field for calling an attention and raising an awareness of the reproductive health problems of women with psychiatric disorders, taking the necessary preventive measures, and developing damage-reducing strategies. © 2013 John Wiley & Sons Ltd.

Application of optimal control strategies to HIV-malaria co-infection dynamics

Science.gov (United States)

Fatmawati; Windarto; Hanif, Lathifah

2018-03-01

This paper presents a mathematical model of HIV and malaria co-infection transmission dynamics. Optimal control strategies such as malaria preventive, anti-malaria and antiretroviral (ARV) treatments are considered into the model to reduce the co-infection. First, we studied the existence and stability of equilibria of the presented model without control variables. The model has four equilibria, namely the disease-free equilibrium, the HIV endemic equilibrium, the malaria endemic equilibrium, and the co-infection equilibrium. We also obtain two basic reproduction ratios corresponding to the diseases. It was found that the disease-free equilibrium is locally asymptotically stable whenever their respective basic reproduction numbers are less than one. We also conducted a sensitivity analysis to determine the dominant factor controlling the transmission. sic reproduction numbers are less than one. We also conducted a sensitivity analysis to determine the dominant factor controlling the transmission. Then, the optimal control theory for the model was derived analytically by using Pontryagin Maximum Principle. Numerical simulations of the optimal control strategies are also performed to illustrate the results. From the numerical results, we conclude that the best strategy is to combine the malaria prevention and ARV treatments in order to reduce malaria and HIV co-infection populations.

Considering strategic litigation as an advocacy tool: a case study of the defence of reproductive rights in Colombia.

Science.gov (United States)

Roa, Mónica; Klugman, Barbara

2014-11-01

Women's Link Worldwide developed a test to determine when an environment is conducive to social change through strategic litigation. We first present our understanding of strategic litigation, and then discuss four conditions for successful and sustainable change using strategic litigation: (1) an existing rights framework; (2) an independent and knowledgeable judiciary; (3) civil society organizations with the capacity to frame social problems as rights violations and to litigate; and (4) a network able to support and leverage the opportunities presented by litigation. Next, we present examples from our work in Colombia that show how analysis of these conditions informed our litigation strategy when confronting a powerful public official who opposes reproductive rights. Two litigation strategies were adopted. The first case was not successful in the courts, but allowed us to introduce our message and build support amongst civil society. The second case built on this momentum and resulted in a victory. Strategic litigation is a powerful tool to advance rights as well as hold governments accountable and ensure compliance with human rights obligations. The strategies developed can be adapted for use in other contexts. We hope they inspire others to protect and promote reproductive rights through strategic litigation when women cannot fully enjoy their rights. Copyright © 2014 Reproductive Health Matters. Published by Elsevier Ltd. All rights reserved.

Inherent and passive safety measures in accelerator driven systems: a safety strategy for ADS

International Nuclear Information System (INIS)

Maschek, W.; Rineiski, A.; Morita, K.; Flad, M.

2001-01-01

The efficiency of Accelerator Driven Systems (ADSs) for the transmutation and incineration of nuclear waste is strongly related to the utilization of so-called dedicated fuels. In the ideal case these fuels should consist of pure TRUs without fertile materials as 238 U or 232 Th to achieve highest incineration/transmutation rates. Dedicated fuels still have to be developed and programs are under way for their fabrication, irradiation and testing. These fertile-free fuels may suffer from deteriorated thermal or thermo-mechanical properties, as a reduced melting point, reduced thermal conductivity or even thermal instability. First analyses have shown that the use of dedicated fuels may lead to a strong deterioration of the safety parameters of the reactor core as e.g. the void worth, the Doppler or the kinetics quantities as neutron generation time and β eff . In addition, a dedicated core may contain multiple ''critical'' fuel masses, resulting in a considerable recriticality potential. Current knowledge on these dedicated fuels suggests that ''critical'' reactors may not be feasible, because of safety reasons. However, for ADSs, the salient hope has been promoted that due to the subcriticality of the system the poor safety features of such fuels could be coped with. Analyses are presented which show potential safety problems for such dedicated cores. Respecting the results of these analyses a safety strategy is proposed along the lines of defense approach in analogy with ideas formerly developed for fast reactors. Inherent and passive safety measures are integrated into the various defense lines. (author)

TH-CD-207B-09: Task-Driven Fluence Field Modulation Design for Model-Based Iterative Reconstruction in CT

International Nuclear Information System (INIS)

Gang, G; Siewerdsen, J; Stayman, J

2016-01-01

Purpose: There has been increasing interest in integrating fluence field modulation (FFM) devices with diagnostic CT scanners for dose reduction purposes. Conventional FFM strategies, however, are often either based on heuristics or the analysis of filtered-backprojection (FBP) performance. This work investigates a prospective task-driven optimization of FFM for model-based iterative reconstruction (MBIR) in order to improve imaging performance at the same total dose as conventional strategies. Methods: The task-driven optimization framework utilizes an ultra-low dose 3D scout as a patient-specific anatomical model and a mathematical formation of the imaging task. The MBIR method investigated is quadratically penalized-likelihood reconstruction. The FFM objective function uses detectability index, d’, computed as a function of the predicted spatial resolution and noise in the image. To optimize performance throughout the object, a maxi-min objective was adopted where the minimum d’ over multiple locations is maximized. To reduce the dimensionality of the problem, FFM is parameterized as a linear combination of 2D Gaussian basis functions over horizontal detector pixels and projection angles. The coefficients of these bases are found using the covariance matrix adaptation evolution strategy (CMA-ES) algorithm. The task-driven design was compared with three other strategies proposed for FBP reconstruction for a calcification cluster discrimination task in an abdomen phantom. Results: The task-driven optimization yielded FFM that was significantly different from those designed for FBP. Comparing all four strategies, the task-based design achieved the highest minimum d’ with an 8–48% improvement, consistent with the maxi-min objective. In addition, d’ was improved to a greater extent over a larger area within the entire phantom. Conclusion: Results from this investigation suggests the need to re-evaluate conventional FFM strategies for MBIR. The task

TH-CD-207B-09: Task-Driven Fluence Field Modulation Design for Model-Based Iterative Reconstruction in CT

Energy Technology Data Exchange (ETDEWEB)

Gang, G; Siewerdsen, J; Stayman, J [Johns Hopkins University, Baltimore, MD (United States)

2016-06-15

Purpose: There has been increasing interest in integrating fluence field modulation (FFM) devices with diagnostic CT scanners for dose reduction purposes. Conventional FFM strategies, however, are often either based on heuristics or the analysis of filtered-backprojection (FBP) performance. This work investigates a prospective task-driven optimization of FFM for model-based iterative reconstruction (MBIR) in order to improve imaging performance at the same total dose as conventional strategies. Methods: The task-driven optimization framework utilizes an ultra-low dose 3D scout as a patient-specific anatomical model and a mathematical formation of the imaging task. The MBIR method investigated is quadratically penalized-likelihood reconstruction. The FFM objective function uses detectability index, d’, computed as a function of the predicted spatial resolution and noise in the image. To optimize performance throughout the object, a maxi-min objective was adopted where the minimum d’ over multiple locations is maximized. To reduce the dimensionality of the problem, FFM is parameterized as a linear combination of 2D Gaussian basis functions over horizontal detector pixels and projection angles. The coefficients of these bases are found using the covariance matrix adaptation evolution strategy (CMA-ES) algorithm. The task-driven design was compared with three other strategies proposed for FBP reconstruction for a calcification cluster discrimination task in an abdomen phantom. Results: The task-driven optimization yielded FFM that was significantly different from those designed for FBP. Comparing all four strategies, the task-based design achieved the highest minimum d’ with an 8–48% improvement, consistent with the maxi-min objective. In addition, d’ was improved to a greater extent over a larger area within the entire phantom. Conclusion: Results from this investigation suggests the need to re-evaluate conventional FFM strategies for MBIR. The task

Reproductive ambition predicts partnered, but not unpartnered, women's preferences for masculine men.

Science.gov (United States)

Watkins, Christopher D

2012-08-01

Changing circumstances alter the costs and benefits of choosing different mates and are thought to be reflected in women's mate preferences. Indeed, several lines of reasoning, and some prior studies, suggest that individual differences in women's preferences for cues of men's underlying health will be more apparent among partnered women than among unpartnered women. The current study shows that preferences for male faces with masculine shape cues, characteristics that are thought to signal men's underlying health, are positively correlated with partnered, but not unpartnered, women's reported reproductive ambition (i.e., their desire to become pregnant). These findings (1) present new evidence for systematic variation in women's mating strategies, (2) suggest that partnership status may be important for potentially adaptive variation in women's mate preferences, and (3) suggest that reproductive ambition may influence women's mate preferences. Alternative explanations for these findings, focusing on the possible effects of a range of variables that may be correlated with reproductive ambition in partnered women and influence their masculinity preferences, are also discussed. ©2011 The British Psychological Society.

Third-party reproduction in the Internet Age: the new, patient-centered landscape.

Science.gov (United States)

Woodward, Julia T

2015-09-01

The rise of the Internet Age has brought a host of sweeping changes to the landscape of third-party reproduction. What began as a dyadic relationship between doctor and patient has evolved into a more complex system in which patients are able to access information online from a variety of external sources. Patients often seek to play a more active role in their third-party reproductive care, and the Internet allows them to do so. Further, demand for both medical and psychosocial information about donors and donor-conceived siblings, available online through patient forums and genetic registries, has altered the perception of gamete donation from a one-time event to an ongoing relationship. The advantages and disadvantages for patients and providers of this freer flow of information between third-party participants are examined. Search motivations of recipients and offspring, as well as types of information sought, are detailed. Recommendations are made regarding strategies fertility programs can use to optimally support their patients and navigate this new landscape. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

36 CFR 705.4 - Reproduction.

Science.gov (United States)

2010-07-01

... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Reproduction. 705.4 Section 705.4 Parks, Forests, and Public Property LIBRARY OF CONGRESS REPRODUCTION, COMPILATION, AND....4 Reproduction. (a) Library of Congress staff acting under the general authority of the Librarian of...

Transcriptome analysis of reproductive tissue and intrauterine developmental stages of the tsetse fly (Glossina morsitans morsitans

Directory of Open Access Journals (Sweden)

Wu Yineng

2010-03-01

Full Text Available Abstract Background Tsetse flies, vectors of African trypanosomes, undergo viviparous reproduction (the deposition of live offspring. This reproductive strategy results in a large maternal investment and the deposition of a small number of progeny during a female's lifespan. The reproductive biology of tsetse has been studied on a physiological level; however the molecular analysis of tsetse reproduction requires deeper investigation. To build a foundation from which to base molecular studies of tsetse reproduction, a cDNA library was generated from female tsetse (Glossina morsitans morsitans reproductive tissues and the intrauterine developmental stages. 3438 expressed sequence tags were sequenced and analyzed. Results Analysis of a nonredundant catalogue of 1391 contigs resulted in 520 predicted proteins. 475 of these proteins were full length. We predict that 412 of these represent cytoplasmic proteins while 57 are secreted. Comparison of these proteins with other tissue specific tsetse cDNA libraries (salivary gland, fat body/milk gland, and midgut identified 51 that are unique to the reproductive/immature cDNA library. 11 unique proteins were homologus to uncharacterized putative proteins within the NR database suggesting the identification of novel genes associated with reproductive functions in other insects (hypothetical conserved. The analysis also yielded seven putative proteins without significant homology to sequences present in the public database (unknown genes. These proteins may represent unique functions associated with tsetse's viviparous reproductive cycle. RT-PCR analysis of hypothetical conserved and unknown contigs was performed to determine basic tissue and stage specificity of the expression of these genes. Conclusion This paper identifies 51 putative proteins specific to a tsetse reproductive/immature EST library. 11 of these proteins correspond to hypothetical conserved genes and 7 proteins are tsetse specific.

Squalus cubensis Reproduction Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Reproductive data from Squalus cubensis (Cuban dogfish) were opportunistically collected from 2005-2012. Data include those necessary to examine reproductive cycle,...

32 CFR 310.20 - Reproduction fees.

Science.gov (United States)

2010-07-01

... 32 National Defense 2 2010-07-01 2010-07-01 false Reproduction fees. 310.20 Section 310.20... PROGRAM DOD PRIVACY PROGRAM Access by Individuals § 310.20 Reproduction fees. (a) Assessing fees. (1) Charge the individual only the direct cost of reproduction. (2) Do not charge reproduction fees if...

Task-driven image acquisition and reconstruction in cone-beam CT

International Nuclear Information System (INIS)

Gang, Grace J; Stayman, J Webster; Siewerdsen, Jeffrey H; Ehtiati, Tina

2015-01-01

This work introduces a task-driven imaging framework that incorporates a mathematical definition of the imaging task, a model of the imaging system, and a patient-specific anatomical model to prospectively design image acquisition and reconstruction techniques to optimize task performance. The framework is applied to joint optimization of tube current modulation, view-dependent reconstruction kernel, and orbital tilt in cone-beam CT. The system model considers a cone-beam CT system incorporating a flat-panel detector and 3D filtered backprojection and accurately describes the spatially varying noise and resolution over a wide range of imaging parameters in the presence of a realistic anatomical model. Task-based detectability index (d′) is incorporated as the objective function in a task-driven optimization of image acquisition and reconstruction techniques. The orbital tilt was optimized through an exhaustive search across tilt angles ranging ±30°. For each tilt angle, the view-dependent tube current and reconstruction kernel (i.e. the modulation profiles) that maximized detectability were identified via an alternating optimization. The task-driven approach was compared with conventional unmodulated and automatic exposure control (AEC) strategies for a variety of imaging tasks and anthropomorphic phantoms. The task-driven strategy outperformed the unmodulated and AEC cases for all tasks. For example, d′ for a sphere detection task in a head phantom was improved by 30% compared to the unmodulated case by using smoother kernels for noisy views and distributing mAs across less noisy views (at fixed total mAs) in a manner that was beneficial to task performance. Similarly for detection of a line-pair pattern, the task-driven approach increased d′ by 80% compared to no modulation by means of view-dependent mA and kernel selection that yields modulation transfer function and noise-power spectrum optimal to the task. Optimization of orbital tilt identified the

Corticosterone-mediated reproductive decisions: sex allocation, the cost of reproduction and maternal fitness

OpenAIRE

Love, Oliver P.

2007-01-01

Managing reproductive investment within the scope of an individual’s energetic condition is required to maximize fitness. To be successful, individuals must make the correct decisions about when to reproduce, when to abandon an attempt, how many resources to invest in current and future attempts and where those resources should be allocated. These reproductive decisions therefore involve complex life-history trade-offs between an individual’s condition and current reproduction, future reprodu...

42 CFR 9.7 - Reproduction.

Science.gov (United States)

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Reproduction. 9.7 Section 9.7 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS STANDARDS OF CARE FOR CHIMPANZEES HELD IN THE FEDERALLY SUPPORTED SANCTUARY SYSTEM § 9.7 Reproduction. Chimpanzee reproduction is...

From esterilología to reproductive biology: The story of the Mexican assisted reproduction business.

Science.gov (United States)

González-Santos, Sandra P

2016-06-01

This paper provides the first overview of how assisted reproduction emerged and developed in Mexico. In doing so it addresses two broad points: when and how treatments using assisted reproductive technology became common practice within reproductive medicine; and how the Mexican assisted reproduction industry emerged. The paper begins in 1949, when the first medical association dedicated to esterilología - the biomedical area focused on the study of infertility - was established, thus providing the epistemic and professional ground upon which assisted reproductive technology would later thrive. The paper then traces the way in which this biomedical industry developed, from individual doctors in their practices to networks of clinics and from a clinical practice to a reproductive industry. It also describes the different ways in which the professional community and the government have worked towards developing a regulatory frame for the practice of assisted reproduction. The paper is informed by ethnographic work conducted at clinics, conferences, online forums and websites, as well as by analysis of the contemporary national media, government documents and national medical journals from the early mid-twentieth century to the those published today.

Childhood adversity accelerates intended reproductive timing in adolescent girls without increasing interest in infants.

Directory of Open Access Journals (Sweden)

Stephanie Clutterbuck

Full Text Available Women experiencing greater childhood adversity exhibit faster reproductive trajectories. One possible psychological mechanism underlying this phenomenon is an increased interest in infants. Interest in infants is thought to be an adaptation important for successful rearing as it motivates the acquisition of caretaking skills. We investigated the relationships between childhood adversity, intended reproductive timing and interest in infants in a sample of English adolescent girls. Specifically we sought to investigate the relationship between 1 childhood adversity and intended reproductive timing; 2 childhood adversity and interest in infants; and 3 intended reproductive timing and interest in infants. Additionally we explored different methods of measuring interest in infants using self-reported fondness for babies, a forced choice adult versus infant paper-based preference task and a novel computer based attention task using adult and infant stimuli. In total 357 girls aged nine to 14 years participated in the study, which took place in schools. Participants completed the two interest in infants tasks before moving on to a childhood adversity questionnaire. Girls with more childhood adversity reported earlier ideal ages at parenthood. We found some evidence that, contrary to our predictions, girls with less childhood adversity were more interested in infants. There was no relationship between intended reproductive timing and interest in infants. The different measurements for interest in infants were only weakly related, if at all, highlighting the complexity of measuring this construct. Our findings suggest that rather than interest in infants being a mechanism for the effect of childhood adversity on early reproductive timing it might instead be an indicator of future reproductive strategies.

Allocation to reproduction and relative reproductive costs in two species of dioecious Anacardiaceae with contrasting phenology.

Science.gov (United States)

Matsuyama, Shuhei; Sakimoto, Michinori

2008-06-01

The cost of reproduction in dioecious plants is often female-biased. However, several studies have reported no difference in costs of reproduction between the sexes. In this study, the relative reproductive allocation and costs at the shoot and whole-plant levels were examined in woody dioecious Rhus javanica and R. trichocarpa, in order to examine differences between types of phenophase (i.e. physiological stage of development). Male and female Rhus javanica and R. trichocarpa were sampled and the reproductive and vegetative allocation of the shoot were estimated by harvesting reproductive current-year shoots during flowering and fruiting. Measurements were made of the number of reproductive and total current-year shoots per whole plant, and of the basal area increment (BAI). The numbers of reproductive and total current-year shoots per 1-year-old shoot were counted in order to examine the costs in the following year at the shoot level. A female-biased annual reproductive allocation was found; however, the ratio of reproductive current-year shoots per tree and the BAI did not differ between sexes in Rhus javanica and R. trichocarpa. The percentage of 1-year-old shoots with at least one reproductive current-year shoot was significantly male-biased in R. trichocarpa, but not in R. javanica, indicating that there was a relative cost at the shoot level only in R. trichocarpa. The female-biased leaf mass per shoot, an indicator of compensation for costs, was only found in R. javanica. Relative reproductive costs at the shoot level were detected in Rhus trichocarpa, which has simultaneous leafing and flowering, but not in R. javanica, which has leafing followed by flowering. However, the costs for the whole-plant level were diminished in both species. The results suggest that the phenophase type may produce the different costs for R. javanica and R. trichocarpa through the development of a compensation mechanism.

Franchising Reproductive Health Services

Science.gov (United States)

Stephenson, Rob; Tsui, Amy Ong; Sulzbach, Sara; Bardsley, Phil; Bekele, Getachew; Giday, Tilahun; Ahmed, Rehana; Gopalkrishnan, Gopi; Feyesitan, Bamikale

2004-01-01

Objectives Networks of franchised health establishments, providing a standardized set of services, are being implemented in developing countries. This article examines associations between franchise membership and family planning and reproductive health outcomes for both the member provider and the client. Methods Regression models are fitted examining associations between franchise membership and family planning and reproductive health outcomes at the service provider and client levels in three settings. Results Franchising has a positive association with both general and family planning client volumes, and the number of family planning brands available. Similar associations with franchise membership are not found for reproductive health service outcomes. In some settings, client satisfaction is higher at franchised than other types of health establishments, although the association between franchise membership and client outcomes varies across the settings. Conclusions Franchise membership has apparent benefits for both the provider and the client, providing an opportunity to expand access to reproductive health services, although greater attention is needed to shift the focus from family planning to a broader reproductive health context. PMID:15544644

Children's Concepts of Reproduction

Science.gov (United States)

Moore, James E.; Kendall, Diane G.

1971-01-01

Results of this study provide little support for either Freudian or Piagetian theorizing about what the young child thinks of reproduction. Implications for sex education and reproduction information are presented. (Author/CJ)

Reproducing oil paint gloss in print for the purpose of creating reproductions of Old Masters

Science.gov (United States)

Elkhuizen, Willemijn S.; Lenseigne, Boris A. J.; Baar, Teun; Verhofstad, Wim; Tempelman, Erik; Geraedts, Jo M. P.; Dik, Joris

2015-03-01

In the field of Fine Art reproduction, 3D scanning plus 3D printing, combined with dedicated software, now allows to capture and reproduce the color and texture of oil paintings. However, for life-like reproduction of the material appearance of such paintings, the typical gloss and translucency must also be included, which is currently not the case. The aim of this paper is to elaborate on the challenges and results of capturing and reproducing oil paint gloss (next to texture and color) using a scanning and printing system. A sample was hand-made using oil paint and acrylic varnish, and its gloss was then reproduced. A gloss map of the painted sample was acquired using a high end DLSR camera and a simple acquisition protocol. Next, Océ High Resolution 3D printing technology was used to create samples with spatially varying gloss. For this, two different strategies were combined: (1) multilevel half-toning of the colors was used to reproduce matte color layers, and (2) varnish was half-toned on top in increasing coverage to recreate increasing gloss levels. This paper presents an overview of the state-of-the-art literature in gloss reproduction and perception, our process of reproduction as well as the visual evaluation of the quality of the created reproduction.

Offering offspring as food to cannibals: oviposition strategies of Amazonian poison frogs (Dendrobates ventrimaculatus)

NARCIS (Netherlands)

Poelman, E.H.; Dicke, M.

2007-01-01

Species utilizing distinct resources for offspring production often show plasticity in reproductive strategies as a function of resource quality. For species using ephemeral pools, strategies are mainly shaped by a time constraint related to pool stability, resource availability and the colonizing

Assisted reproductive travel: UK patient trajectories.

Science.gov (United States)

Hudson, Nicky; Culley, Lorraine

2011-11-01

Media reporting of 'fertility tourism' tends to portray those who travel as a cohesive group, marked by their desperation and/or selfishness and propensity towards morally questionable behaviour. However, to date little has been known about the profile of those leaving the UK for treatment. This paper discusses the first UK-based study of patient assisted reproduction travel that was designed to explore individual travel trajectories. It is argued that existing ways of conceptualizing cross-border reproductive care as 'fertility or reproductive tourism' are in danger of essentializing what the data suggest are diverse, complex and often ambiguous motivations for reproductive travel. The concept of seriality is used to suggest that, whilst 'reproductive tourists' share some characteristics, they also differ in significant ways. This paper argues that, through an examination of the personal landscapes of fertility travel, the diverse processes involved in reproductive travel can be better understood and policymakers can be assisted to avoid what might be regarded as simplistic responses to cross-border reproductive care. Copyright © 2011 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Selective Reproductive Technologies

DEFF Research Database (Denmark)

Gammeltoft, Tine; Wahlberg, Ayo

2014-01-01

From a historical perspective, selective reproduction is nothing new. Infanticide, abandonment, and selective neglect of children have a long history, and the widespread deployment of sterilization and forced abortion in the twentieth century has been well documented. Yet in recent decades select......, discussing how selective reproduction engages with issues of long-standing theoretical concern in anthropology, such as politics, kinship, gender, religion, globalization, and inequality....... (ARTs), what we term selective reproductive technologies (SRTs) are of a more specific nature: Rather than aiming to overcome infertility, they are used to prevent or allow the birth of certain kinds of children. This review highlights anthropological research into SRTs in different parts of the world...

Incremental cost-effectiveness of algorithm-driven genetic testing versus no testing for Maturity Onset Diabetes of the Young (MODY) in Singapore.

Science.gov (United States)

Nguyen, Hai Van; Finkelstein, Eric Andrew; Mital, Shweta; Gardner, Daphne Su-Lyn

2017-11-01

Offering genetic testing for Maturity Onset Diabetes of the Young (MODY) to all young patients with type 2 diabetes has been shown to be not cost-effective. This study tests whether a novel algorithm-driven genetic testing strategy for MODY is incrementally cost-effective relative to the setting of no testing. A decision tree was constructed to estimate the costs and effectiveness of the algorithm-driven MODY testing strategy and a strategy of no genetic testing over a 30-year time horizon from a payer's perspective. The algorithm uses glutamic acid decarboxylase (GAD) antibody testing (negative antibodies), age of onset of diabetes (30 years) to stratify the population of patients with diabetes into three subgroups, and testing for MODY only among the subgroup most likely to have the mutation. Singapore-specific costs and prevalence of MODY obtained from local studies and utility values sourced from the literature are used to populate the model. The algorithm-driven MODY testing strategy has an incremental cost-effectiveness ratio of US$93 663 per quality-adjusted life year relative to the no testing strategy. If the price of genetic testing falls from US$1050 to US$530 (a 50% decrease), it will become cost-effective. Our proposed algorithm-driven testing strategy for MODY is not yet cost-effective based on established benchmarks. However, as genetic testing prices continue to fall, this strategy is likely to become cost-effective in the near future. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Facultative asexual reproduction and genetic diversity of populations in the humivorous termite Cavitermes tuberosus

Czech Academy of Sciences Publication Activity Database

Fournier, D.; Hellemans, S.; Hanus, Robert; Roisin, Y.

2016-01-01

Roč. 283, č. 1832 (2016), č. článku 20160196. ISSN 0962-8452 R&D Projects: GA ČR(CZ) GA14-12774S Institutional support: RVO:61388963 Keywords : thelytokous parthenogenesis * breeding systems * termites * reproductive strategies * Isoptera * Termitidae Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.940, year: 2016

Exploring a Cultural Initiative: The Opus College of Business's Mission-Driven Catholic Business Education Seminar

Science.gov (United States)

Shoemake, Robert C.

2012-01-01

This article examines and evaluates the development, design, and impact of one strategy for renewing mission and identity in Catholic business education. The Mission-Driven Catholic Business Education (MCBE) Seminar is used by the Opus College of Business at the University of St. Thomas to create and sustain a mission-driven culture. (Contains 1…

The market for reproductive tourism: an analysis with special reference to Greece.

Science.gov (United States)

Paraskou, Anastasia; George, Babu P

2017-01-01

For many people, the need for parenthood remains unfulfilled due to biological reasons and a remedy for these individuals is assisted reproduction (AR). Because of widely differing and sometimes incompatible legislations around the world related to AR, there is considerable confusion across national borders. Within Europe, Greece seems to be in a comparatively favorable position because of lower restrictions and the availability of decent quality specialized medical facilities. This research is a market study with a business perspective and explores the emerging landscape of reproductive tourism (RT) in Greece. The research adopted mixed methods. First, open-ended questions were used to interview foreign medical tourists and staff in various AR clinics. Based on the insights from these interviews and guided by the extent literature, a survey instrument was prepared and administered among 130 patients. Findings indicate that Greece still lack policies that nurture transparency and dynamic response to technological changes in AR. Also, the travel industry lack specialists who can effectively liaison with clinics, who understand the availability of AR technologies, regulations, and the unique needs of AR tourists. Globally, the need for assisted reproduction has tremendously increased; yet, the supply of facilities is lagging far behind. There is a unique advantage for clinics located in touristic locations in countries that offer cheaper treatment options. Given the shape of its debt-ridden economy, Greece needs foreign exchange inflows and gaining first mover advantage in reproductive tourism is probably an important way to achieve this. This research draws up a reproductive tourism strategy for Greece.

Root-lesion nematodes suppress cabbage aphid population development by reducing aphid daily reproduction

Directory of Open Access Journals (Sweden)

W. H. Gera eHol

2016-02-01

Full Text Available Empirical studies have shown that belowground feeding herbivores can affect the performance of aboveground herbivores in different ways. Often the critical life-history parameters underlying the observed performance effects remain unexplored. In order to better understand the cause for the observed effects on aboveground herbivores, these ecological mechanisms must be better understood. In this study we combined empirical experiments with a modelling approach to analyse the effect of two root feeding endoparasitic nematodes with different feeding strategies on the population growth of the aboveground feeding specialist aphid Brevicoryne brassicae on Brassica nigra. The aim was to test whether emerging differences in life history characteristics (days until reproduction, daily reproduction would be sufficient to explain observed differences in aphid population development on plants with and without two species of nematodes. Aphid numbers were lower on plants with Pratylenchus penetrans in comparison to aphid numbers on plants with Meloidogyne spp. A dedicated experiment showed that aphid daily reproduction was lower on plants with P. penetrans (3.08 offspring per female per day in comparison to both uninfested plants and plants with Meloidogyne spp. (3.50 offspring per female per day. The species-specific reduction of aphid reproduction appeared independent of changes in amino acids, soluble sugars or the glucosinolate sinigrin in the phloem. An individual-based model revealed that relatively small differences in reproduction rate per female were sufficient to yield a similar difference in aphid populations as was found in the empirical experiments.

The effect of female quality on male ejaculatory expenditure and reproductive success in a praying mantid.

Directory of Open Access Journals (Sweden)

Anuradhi Jayaweera

Full Text Available Strategic ejaculation is a behavioural strategy shown by many animals as a response to sperm competition and/or as a potential mechanism of cryptic male choice. Males invest more mating resources when the risk of sperm competition increases or they invest more in high quality females to maximize their reproductive output. We tested this hypothesis in the false garden mantid Pseudomantis albofimbriata, where females are capable of multiply mating and body condition is an indicator of potential reproductive fitness. We predicted male mantids would ejaculate strategically by allocating more sperm to high quality females. To determine if and how males alter their ejaculate in response to mate quality, we manipulated female food quantity so that females were either in good condition with many eggs (i.e. high quality or poor condition with few eggs (i.e. low quality. Half of the females from each treatment were used in mating trials in which transferred sperm was counted before fertilisation occurred and the other half of females were used in mating trials where fertilisation occurred and ootheca mass and total eggs in the ootheca were recorded. Opposed to our predictions, the total number of sperm and the proportion of viable sperm transferred did not vary significantly between female treatments. Male reproductive success was entirely dependent on female quality/fecundity, rather than on the number of sperm transferred. These results suggest that female quality is not a major factor influencing postcopulatory male mating strategies in P. albofimbriata, and that sperm number has little effect on male reproductive success in a single mating scenario.

Occupational Therapy and Sexual and Reproductive Health Promotion in Adolescence: A Case Study.

Science.gov (United States)

Gontijo, Daniela Tavares; de Sena e Vasconcelos, Anna Carolina; Monteiro, Rosana Juliet Silva; Facundes, Vera Lúcia Dutra; Trajano, Maria de Fátima Cordeiro; de Lima, Luciane Soares

2016-03-01

Occupational therapy can contribute to sexual and reproductive health through health education. The purpose of this study was to describe an occupational therapy intervention aimed at sexual and reproductive health promotion in adolescents. Fifty-eight adolescents were involved in the study, before, during and after the interventions. Educative activities such as puzzles, storytelling, mime and board games were used, which occupational therapy faculty and students had constructed. The games were employed as mediators for gaining knowledge in sexual and reproductive health. Outcome was measured using a questionnaire, audio recordings and field diaries. The data were analysed by descriptive statistics and thematic content analysis. The results showed the adolescents' increased knowledge of sexual and reproductive health information immediately after the intervention. The thematic analysis was grouped into three categories: the adolescents' initial expectations regarding the project, reflections on the process experienced during the interventions and use of educational games by occupational therapists. The importance of rapport and dialogue was highlighted in the construction of interventions based on participatory methods. The absence of a longitudinal follow-up is a limitation in this study. Further research is important to systematically assess sexual health promotion strategies in adolescence. Copyright © 2015 John Wiley & Sons, Ltd.

Maternal Transfer of Vitamin C in Channel Catfish (Ictalurus Punctatus) Effects Reproduction and Progeny Performance

Science.gov (United States)

Two routes of maternal transfer of vitamin C in channel catfish female broodfish prior to spawning were explored as a strategy to incorporate the vitamin to determine its effect on reproduction and subsequent performance of the progeny. Accumulation of vitamin C was higher (p<0.05) in ovarian tissu...

Predator avoidance during reproduction: diel movements by spawning sockeye salmon between stream and lake habitats.

Science.gov (United States)

Bentley, Kale T; Schindler, Daniel E; Cline, Timothy J; Armstrong, Jonathan B; Macias, Daniel; Ciepiela, Lindsy R; Hilborn, Ray

2014-11-01

Daily movements of mobile organisms between habitats in response to changing trade-offs between predation risk and foraging gains are well established; however, less in known about whether similar tactics are used during reproduction, a time period when many organisms are particularly vulnerable to predators. We investigated the reproductive behaviour of adult sockeye salmon (Oncorhynchus nerka) and the activity of their principal predator, brown bears (Ursus arctos), on streams in south-western Alaska. Specifically, we continuously monitored movements of salmon between lake habitat, where salmon are invulnerable to bears, and three small streams, where salmon spawn and are highly vulnerable to bears. We conducted our study across 2 years that offered a distinct contrast in bear activity and predation rates. Diel movements by adult sockeye salmon between stream and lake habitat were observed in 51.3% ± 17.7% (mean ± SD) of individuals among years and sites. Fish that moved tended to hold in the lake for most of the day and then migrated into spawning streams during the night, coincident with when bear activity on streams tended to be lowest. Additionally, cyclic movements between lakes and spawning streams were concentrated earlier in the spawning season. Individuals that exhibited diel movements had longer average reproductive life spans than those who made only one directed movement into a stream. However, the relative effect was dependent on the timing of bear predation, which varied between years. When predation pressure primarily occurred early in the spawning run (i.e., during the height of the diel movements), movers lived 120-310% longer than non-movers. If predation pressure was concentrated later in the spawning run (i.e. when most movements had ceased), movers only lived 10-60% longer. Our results suggest a dynamic trade-off in reproductive strategies of sockeye salmon; adults must be in the stream to reproduce, but must also avoid predation long

46 CFR 380.21 - Reproduction.

Science.gov (United States)

2010-10-01

... 46 Shipping 8 2010-10-01 2010-10-01 false Reproduction. 380.21 Section 380.21 Shipping MARITIME... Reproduction. (a) The records described in § 380.24 may be microfilmed or otherwise reproduced in lieu of their retention in original form: Provided, That such reproductions shall not be made prior to completion of the...

Zika virus and assisted reproduction.

Science.gov (United States)

Cordeiro, Christina N; Bano, Rashda; Washington Cross, Chantel I; Segars, James H

2017-06-01

Due to the fact that the Zika virus can be sexually transmitted, there is a potential risk for disease transmission at several stages of assisted reproduction. Such a possibility poses a serious challenge to couples pursing fertility with reproductive technologies. Here, we discuss what is known regarding Zika virus infection with respect to sexual transmission and correlate this knowledge with recent recommendations in the realm of infertility treatment. Zika virus can be transmitted from infected men and women through vaginal, oral or anal intercourse. Zika virus RNA has been detected in blood, semen, cervical mucus and vaginal fluid. Currently, the Centers for Disease Control recommends that infected men wait 6 months, and infected women 8 weeks, prior to attempting pregnancy. Reproductive tissue donors should wait 6 months before giving a specimen. Further study of Zika virus transmission in different reproductive tissues and establishment of validated testing methods for viral disease transmissibility are urgently needed. Reproductive technologists need to establish screening, testing and laboratory protocols aimed to reduce the risk of Zika virus transmission during assisted reproduction.

Strategies to improve the performance of three-phase induction motor driven systems

OpenAIRE

Ferreira, Fernando José Teixeira Estêvão

2009-01-01

Tese de doutoramento em Engenharia Electrotécnica (Sistemas de Energia) apresentada à Fac. de Ciências e Tecnologia da Universidade de Coimbra Electric motor driven systems (EMODS) account for over 40% of global electrical energy demand, i.e., 7400 TWh per year, and for about 70% of the demand for industrial electrical energy, being by far the most important electrical load. Furthermore, EMODS offer today large efficiency improvement potential, on average within 20% to 30%. If the energy s...

Coping by Copying? Higher Education Institutions' Student Recruitment Strategies

Science.gov (United States)

Frolich, Nicoline; Brandt, Synnove; Hovdhaugen, Elisabeth; Aamodt, Per Olaf

2009-01-01

Growing national and international competition for students puts pressure on higher education institutions (HEIs) to develop marketing and student recruitment strategies; these are also driven by financial stress caused by performance-based funding mechanisms. In this paper we explore Norwegian HEIs' student recruitment strategies. What type of…

The Enterprise Social Media Relations Strategy

DEFF Research Database (Denmark)

Agerdal-Hjermind, Annette

2014-01-01

The purpose of this article is to show and discuss how corporate social media usage is driven by people, not technology, and how the creation of a culture of participation on the part of a company, in this case the Danish shipping company, Maersk Line, requires a systematic, user-driven listen......-and-learn strategy with a clear selection of purpose and social platform according to audience and topics. This effort needs to be continuously dedicated and aligned, focusing on which relationships the company wants to form....

Freeze-all cycle in reproductive medicine: current perspectives.

Science.gov (United States)

Roque, Matheus; Valle, Marcello; Kostolias, Alessandra; Sampaio, Marcos; Geber, Selmo

2017-02-01

The freeze-all strategy has emerged as an alternative to fresh embryo transfer (ET) during in vitro fertilization (IVF) cycles. Although fresh ET is the norm during assisted reproductive therapies (ART), there are many concerns about the possible adverse effects of controlled ovarian stimulation (COS) over the endometrium. The supra-physiologic hormonal levels that occur during a conventional COS are associated with modifications in the peri-implantation endometrium, which may be related to a decrease in pregnancy rates and poorer obstetric and perinatal outcomes when comparing fresh to frozen-thawed embryo transfers. The main objective of this study was to assess the available literature regarding the freeze-all strategy in IVF cycles, in regards to effectiveness and safety. Although there are many potential advantages in performing a freeze-all cycle over a fresh ET, it seems that the freeze-all strategy is not designed for all IVF patients. There is a need to develop a non-invasive clinical tool to evaluate the endometrial receptivity during a fresh cycle, which enables the selection of patients that would benefit from this strategy. Today, it is reasonable to perform elective cryopreservation of all oocytes/embryos in cases with a risk of OHSS development, and in patients with supra-physiologic hormonal levels during the follicular phase of COS. It is not clear if all normal responders and poor responders may benefit from this strategy.

Reproductive history of cane rat: a review of the reproduction and ...

African Journals Online (AJOL)

This study evaluates in a review the reproduction and reproductive performance of cane rat. Breeding time in cane rat depends on which part of Africa the Animal is found and the weather. In the wild, cane rat lives in groups of males and females during the breeding season. The wet season of the year is the usual breeding ...

Introduction: Communicating Reproduction.

Science.gov (United States)

Hopwood, Nick; Jones, Peter Murray; Kassell, Lauren; Secord, Jim

2015-01-01

Communication should be central to histories of reproduction, because it has structured how people do and do not reproduce. Yet communication has been so pervasive, and so various, that it is often taken for granted and the historical specificities overlooked. Making communication a frame for histories of reproduction can draw a fragmented field together, including by putting the promotion of esoteric ideas on a par with other practical activities. Paying communication close attention can revitalize the history of reproduction over the long term by highlighting continuities as well as the complex connections between new technologies and new approaches. Themes such as the power of storytelling, the claiming and challenging of expertise, and relations between knowledge and ignorance, secrecy and propriety also invite further study.

Enhanced Control for a Direct-driven Permanent Synchronous Generator Wind-power Generation System with Flywheel Energy Storage Unit Under Unbalanced Grid Fault

DEFF Research Database (Denmark)

Yao, Jun; Zhou, Te; Hu, Weihao

2015-01-01

This article presents an enhanced control strategy for a direct-driven permanent synchronous generator based wind-power generation system with a flywheel energy storage unit. The behaviors of the direct-driven permanent magnet synchronous generator system with a flywheel energy storage unit under......, the DC-link voltage oscillations can be effectively suppressed during the unbalanced grid fault by controlling the flywheel energy storage unit. Furthermore, a proportional–integral-resonant controller is designed for the flywheel motor to eliminate the oscillations in the DC-link voltage. Finally......, the proposed coordinated control strategy for the direct-driven permanent magnet synchronous generator system with a flywheel energy storage unit has been validated by the simulation results of a 1-MW direct-driven permanent magnet synchronous generator wind power generation system with a flywheel energy...

Sex-Linked Mating Strategies Diverge with a Manipulation of Genital Salience.

Science.gov (United States)

Fetterman, Adam K; Kruger, Nicole N; Robinson, Michael D

2015-02-01

Trivers (1972) proposed that evolutionary factors should favor divergent mating strategies for males versus females. Such differences may be less pronounced among human beings than other animals and social norms and sex roles are also pertinent influences. The present experiment ( N = 133 college undergraduates, 74 female) sought to bypass some of these other influences. Participants were randomly assigned to a condition designed to increase attention to the genital region (a downward pointing arrow) or not (an upward pointing arrow). They then reported on their interest in short-term (e.g., a one-night stand) and long-term (e.g., a potential marital partner) mating opportunities. A theory-consistent three-way interaction occurred such that the genital salience manipulation primed a shorter-term reproductive strategy among men and a longer-term reproductive strategy among women. The results provide unique support for evolution-linked ideas about sex differences in the form of a role for bodily attention.

Variation in male reproductive longevity across traditional societies.

Directory of Open Access Journals (Sweden)

Lucio Vinicius

Full Text Available Most accounts of human life history propose that women have short reproductive spans relative to their adult lifespans, while men not only remain fertile but carry on reproducing until late life. Here we argue that studies have overlooked evidence for variation in male reproductive ageing across human populations. We apply a Bayesian approach to census data from Agta hunter-gatherers and Gambian farmers to show that long post-reproductive lifespans characterise not only women but also males in some traditional human populations. We calculate three indices of reproductive ageing in men (oldest age at reproduction, male late-life reproduction, and post-reproductive representation and identify a continuum of male reproductive longevity across eight traditional societies ranging from !Kung, Hadza and Agta hunter-gatherers exhibiting low levels of polygyny, early age at last reproduction and long post-reproductive lifespans, to male Gambian agriculturalists and Turkana pastoralists showing higher levels of polygyny, late-life reproduction and shorter post-reproductive lifespans. We conclude that the uniquely human detachment between rates of somatic senescence and reproductive decline, and the existence of post-reproductive lifespans, are features of both male and female life histories, and therefore not exclusive consequences of menopause.

Reproduction in the space environment: Part I. Animal reproductive studies

Science.gov (United States)

Santy, P. A.; Jennings, R. T.; Craigie, D.

1990-01-01

Mankind's exploration and colonization of the frontier of space will ultimately depend on men's and women's ability to live, work, and reproduce in the space environment. This paper reviews animal studies, from microorganisms to mammals, done in space or under space-simulated conditions, which identify some of the key areas which might interfere with human reproductive physiology and/or embryonic development. Those space environmental factors which impacted almost all species included: microgravity, artificial gravity, radiation, and closed life support systems. These factors may act independently and in combination to produce their effects. To date, there have been no studies which have looked at the entire process of reproduction in any animal species. This type of investigation will be critical in understanding and preventing the problems which will affect human reproduction. Part II will discuss these problems directly as they relate to human physiology.

Biological differences in reproductive strategy between the mosquito sibling species Anopheles gambiae sensu stricto and An. quadriannulatus

NARCIS (Netherlands)

Takken, W.; Stuke, K.; Klowden, M.J.

2002-01-01

Females of the afrotropical mosquito species Anopheles gambiae Giles sensu stricto and An. quadriannulatus (Theobald) (Diptera: Culicidae) were studied for the effect of blood meal size and the frequency of blood feeding on reproductive development during the first gonotrophic cycle. To standardize

Strategies needed to involve men, other family members.

Science.gov (United States)

Barnett, B

1998-01-01

Women typically do not make decisions about contraceptive use and family planning on their own, and many women often have little, if any, decision-making power in the home. Strategies are therefore needed to empower women, educate family members, and involve men in reproductive health programs. Policymakers should expand the range of male services and encourage the greater use of male contraceptive methods. Furthermore, health programs should include counseling to help men and women improve their communications skills and conduct education campaigns to inform men about the roles they can play in family planning. Men should also learn about the side effects of both male and female methods, since concern over method side effects can frustrate their support of family planning. Appropriate strategies can be tailored to meet individual group needs. Programs in Madagascar, Bangladesh, Honduras, and Nepal are described as examples of how the support of family members can positively affect family planning use and reproductive health.

Assisted Reproduction: What factors interfere in the professional's decisions? Are single women an issue?

Directory of Open Access Journals (Sweden)

Tarlatzis Basil C

2011-05-01

Full Text Available Abstract Background With the development of medical technology, many countries around the world have been implementing ethical guidelines and laws regarding Medically Assisted Reproduction (MAR. A physician's reproductive decisions are not solely based on technical criteria but are also influenced by society values. Therefore, the aim of this study was to analyze the factors prioritized by MAR professionals when deciding on whether to accept to perform assisted reproduction and to show any existing cultural differences. Methods Cross-sectional study involving 224 healthcare professionals working with assisted reproduction in Brazil, Italy, Germany and Greece. Instrument used for data collection: a questionnaire, followed by the description of four special MAR cases (a single woman, a lesbian couple, an HIV discordant couple and gender selection which included case-specific questions regarding the professionals' decision on whether to perform the requested procedure as well as the following factors: socio-demographic variables, moral and legal values as well as the technical aspects which influence decision-making. Results Only the case involving a single woman who wishes to have a child (without the intention of having a partner in the future demonstrated significant differences. Therefore, the study was driven towards the results of this case specifically. The analyses we performed demonstrated that professionals holding a Master's Degree, those younger in age, female professionals, those having worked for less time in reproduction, those in private clinics and Brazilian health professionals all had a greater tendency to perform the procedure in that case. A multivariate analysis demonstrated that the reasons for the professional's decision to perform the procedure were the woman's right to gestate and the duty of MAR professionals to help her. The professionals who decided not to perform the procedure identified the woman's marital status and

Male reproductive health and yoga

Directory of Open Access Journals (Sweden)

Pallav Sengupta

2013-01-01

Full Text Available Now-a-days reproductive health problems along with infertility in male is very often observed. Various Assisted Reproductive Technologies have been introduced to solve the problem, but common people cannot afford the cost of such procedures. Various ayurvedic and other alternative medicines, along with regular yoga practice are proven to be not only effective to enhance the reproductive health in men to produce a successful pregnancy, but also to regulate sexual desire in men who practice celibacy. Yoga is reported to reduce stress and anxiety, improve autonomic functions by triggering neurohormonal mechanisms by the suppression of sympathetic activity, and even, today, several reports suggested regular yoga practice from childhood is beneficial for reproductive health. In this regard the present review is aimed to provide all the necessary information regarding the effectiveness of yoga practice to have a better reproductive health and to prevent infertility.

Floral and reproductive biology of Alcantarea nahoumii (Bromeliaceae, a vulnerable endemic species of the Atlantic Forest

Directory of Open Access Journals (Sweden)

Maria Josirene Souza Moreira Bastos

Full Text Available ABSTRACT Alcantarea nahoumii occurs exclusively in the state of Bahia, Brazil, and is classified as vulnerable due to deforestation and frequent fires in the region. Knowledge of floral and reproductive biology is fundamental to understanding ecological interactions, as well as the reproductive success of plant species. The objective of this study was to evaluate the floral and reproductive biology of A. nahoumii in an Atlantic Forest fragment with regard to phenology, pollen viability, stigma receptivity, pollination ecology and reproductive systems, all of which are important parameters for of the development of conservation strategies for the species. Anthesis is diurnal and heterogeneous, starting at 6:30 a.m. and lasting until 8:00 a.m. Highest germination percentages and greatest pollen tube lengths were obtained in BK culture medium. Histochemical tests revealed high pollen viability (89.71 %. Stigma receptivity occurred during anthesis and lasted for up to 24 hours after floral opening. Alcantarea nahoumii exhibited preferential allogamy and self-compatibility, and required a pollinator to production of viable seeds. Sixteen species of pollinators were observed visiting A. nahoumii, among which were five hummingbird species. Even though its reproductive system is efficient, this bromeliad remains threatened mainly due to habitat fragmentation caused by deforestation, burning and predatory extractivism.

Reproductive Life Planning: Raising the Questions.

Science.gov (United States)

Morse, Jessica E; Moos, Merry-K

2018-04-01

Introduction Unintended pregnancy has been a concerning public health problem for decades. As we begin to understand the complexities of pregnancy intention and how women experience these pregnancies, reproductive life planning offers a paradigm shift. Methods Reproductive life planning is a patient-centered approach that places a patient's reproductive preferences-whether concrete or ambivalent-at the forefront of her clinical care. Results This process grants women and men the opportunity to consider how reproduction fits within the context of their broader lives. Within a clinical encounter, reproductive life planning allows counseling and care to be tailored to patient preferences. Discussion Although there is great potential for positive public health impacts in unintended pregnancy, contraceptive use and improved preconception health, the true benefit lies within reinforcing reproductive empowerment. Despite recommendations for universal adoption, many questions remain regarding implementation, equity and outcomes.

Floral heterochrony promotes flexibility of reproductive strategies in the morphologically homogeneous genus Eugenia (Myrtaceae).

Science.gov (United States)

Vasconcelos, Thais N C; Lucas, Eve J; Faria, Jair E Q; Prenner, Gerhard

2018-01-25

Comparative floral ontogeny represents a valuable tool to understand angiosperm evolution. Such an approach may elucidate subtle changes in development that discretely modify floral architecture and underlie reproductive lability in groups with superficial homogeneous morphology. This study presents a comparative survey of floral development in Eugenia (Myrtaceae), one of the largest genera of angiosperms, and shows how previously undocumented ontogenetic trends help to explain the evolution of its megadiversity in contrast to its apparent flower uniformity. Using scanning electron microscopy, selected steps of the floral ontogeny of a model species (Eugenia punicifolia) are described and compared with 20 further species representing all ten major clades in the Eugenia phylogenetic tree. Additional floral trait data are contrasted for correlation analysis and character reconstructions performed against the Myrtaceae phylogenetic tree. Eugenia flowers show similar organ arrangement patterns: radially symmetrical, (most commonly) tetramerous flowers with variable numbers of stamens and ovules. Despite a similar general organization, heterochrony is evident from size differences between tissues and structures at similar developmental stages. These differences underlie variable levels of investment in protection, subtle modifications to symmetry, herkogamic effects and independent androecium and gynoecium variation, producing a wide spectrum of floral display and contributing to fluctuations in fitness. During Eugenia's bud development, the hypanthium (as defined here) is completely covered by stamen primordia, unusual in other Myrtaceae. This is the likely plesiomorphic state for Myrteae and may have represented a key evolutionary novelty in the tribe. Floral evolution in Eugenia depends on heterochronic patterns rather than changes in complexity to promote flexibility in floral strategies. The successful early establishment of Myrteae, previously mainly linked to the

21 CFR 884.6130 - Assisted reproduction microtools.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Assisted reproduction microtools. 884.6130 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6130 Assisted reproduction microtools. (a) Identification. Assisted reproduction microtools are pipettes or...

[Ethics and reproductive health: the issue of HPV vaccination].

Science.gov (United States)

Matejić, Bojana; Kesić, Vesna

2013-01-01

The ethics of reproductive health covers a wide field of different issues, from the ethical dimensions of assisted reproduction, life of newborns with disabilities to the never-ending debate on the ethical aspects of abortion. Furthermore, increasing attention is paid to the ethical dimensions of using stem cells taken from human embryos, the creation of cloned embryos of patients for possible self-healing, and the increasingly present issue of reproductive cloning. Development of vaccines against human papillomavirus (HPV) has introduced new ethical aspects related to reproductive health and the need for a consensus of clinical and public-healthcare population. Today immunization with HPV vaccine is a measure for the primary prevention of cervical cancer and it provides effective protection against certain types of viruses included in the vaccine. The most often mentioned issues of discussions on ethical concerns about HPV vaccination are the recommended age of girls who should be informed and vaccinated (12-14 years), attitudes and fears of parents concerning discussion with their preadolescent daughters on issues important for their future sexual behavior, dilemma on the vaccination of boys and the role of the chosen pediatrician in providing information on the vaccination. In Serbia, two HPV vaccines have been registered but the vaccination is not compulsory. Up-till-now there has been no researches on the attitudes of physicians and parents about HPV vaccination. Nevertheless, it is very important to initiate education of general and medical public about the fact that the availability of vaccine, even if we disregard all aforementioned dilemmas, does not lead to the neglect of other preventive strategies against cervical cancer, primarily screening. The National Program for Cervical Cancer Prevention involves organized screening, i.e. regular cytological examinations of the cervical smear of all women aged 25-69 years, every three years, regardless of the

Ethics and reproductive health: The issue of HPV vaccination

Directory of Open Access Journals (Sweden)

Matejić Bojana

2013-01-01

Full Text Available The ethics of reproductive health covers a wide field of different issues, from the ethical dimensions of assisted reproduction, life of newborns with disabilities to the never-ending debate on the ethical aspects of abortion. Furthermore, increasing attention is paid to the ethical dimensions of using stem cells taken from human embryos, the creation of cloned embryos of patients for possible self-healing, and the increasingly present issue of reproductive cloning. Development of vaccines against human papillomavirus (HPV has introduced new ethical aspects related to reproductive health and the need for a consensus of clinical and public-healthcare population. Today immunization with HPV vaccine is a measure for the primary prevention of cervical cancer and it provides effective protection against certain types of viruses included in the vaccine. The most often mentioned issues of discussions on ethical concerns about HPV vaccination are the recommended age of girls who should be informed and vaccinated (12-14 years, attitudes and fears of parents concerning discussion with their preadolescent daughters on issues important for their future sexual behavior, dilemma on the vaccination of boys and the role of the chosen pediatrician in providing information on the vaccination. In Serbia, two HPV vaccines have been registered but the vaccination is not compulsory. Up-till-now there has been no researches on the attitudes of physicians and parents about HPV vaccination. Nevertheless, it is very important to initiate education of general and medical public about the fact that the availability of vaccine, even if we disregard all aforementioned dilemmas, does not lead to the neglect of other preventive strategies against cervical cancer, primarily screening. The National Program for Cervical Cancer Prevention involves organized screening, i.e. regular cytological examinations of the cervical smear of all women aged 25-69 years, every three years

Changes in ethnic structure of population in the light of recent trends of migration and natural reproduction

Directory of Open Access Journals (Sweden)

Novotný Ladislav

2015-01-01

Full Text Available The paper aims to assess the impact of migration and natural reproduction of population to the changes in ethnic structure of population by the case study of three multi-ethnic functional urban regions in Slovakia. All three regions are located at the Slovak-Hungarian ethnic border and are characterized by larger proportion of Slovaks and lower proportion of Hungarians in the core than in the ring. The regions were chosen also with intent to provide a sample with various processes of spatial redistribution of population taking place, which are described in the paper. The ethnic structure at the levels of whole regions, their basic components - cores and rings - is introduced briefly. The analyses of changes in the ethnic structure and its relationships with the natural reproduction and migration of population provides interesting results. It was proved that the migration is a driving force in changes of ethnic structure in analysed regions, even though the patterns of natural reproduction behaviors between ethnic Slovaks and Hungarians are traditionally different. Since the most intensive process of spatial redistribution of population is the decentralization from the cores to the rings of the regions driven by migration, the ethnic structure of the rings tends to approximate to that in the cores.

Employer-driven consumerism: integrating health into the business model.

Science.gov (United States)

Thompson, Michael; Checkley, Joseph

2006-01-01

Consumer-driven health care is a misnomer. Notwithstanding the enormous role the individual consumer has to play in reshaping the U.S. health care delivery system, this article will focus on the employer as the key driver of change and innovation in the consumerism revolution. American Standard provides a case study of how one major employer has evaluated health care in the context of its business and aggressively integrated consumerism and health into the core of its business. Other companies will appropriately execute consumerism strategies in a fashion consistent with their own needs, culture, resources and populations. However, the principles supporting those strategies will be very much consistent.

Collaborative Project: The problem of bias in defining uncertainty in computationally enabled strategies for data-driven climate model development. Final Technical Report.

Energy Technology Data Exchange (ETDEWEB)

Huerta, Gabriel [Univ. of New Mexico, Albuquerque, NM (United States)

2016-05-10

The objective of the project is to develop strategies for better representing scientific sensibilities within statistical measures of model skill that then can be used within a Bayesian statistical framework for data-driven climate model development and improved measures of model scientific uncertainty. One of the thorny issues in model evaluation is quantifying the effect of biases on climate projections. While any bias is not desirable, only those biases that affect feedbacks affect scatter in climate projections. The effort at the University of Texas is to analyze previously calculated ensembles of CAM3.1 with perturbed parameters to discover how biases affect projections of global warming. The hypothesis is that compensating errors in the control model can be identified by their effect on a combination of processes and that developing metrics that are sensitive to dependencies among state variables would provide a way to select version of climate models that may reduce scatter in climate projections. Gabriel Huerta at the University of New Mexico is responsible for developing statistical methods for evaluating these field dependencies. The UT effort will incorporate these developments into MECS, which is a set of python scripts being developed at the University of Texas for managing the workflow associated with data-driven climate model development over HPC resources. This report reflects the main activities at the University of New Mexico where the PI (Huerta) and the Postdocs (Nosedal, Hattab and Karki) worked on the project.

The Mahabharata and reproductive endocrinology

OpenAIRE

Kalra, Bharti; Baruah, Manash P.; Kalra, Sanjay

2016-01-01

This communication approaches the Mahabharata through the prism of reproductive endocrinology. Descriptions of episodes related to reproduction are listed here, to provide fodder for the endocrinologically minded brain. The cases described here are perhaps, the first documented observations of fetal orgasm, pseudocyesis and assisted reproductive technology, including assisted insemination by donor, induction of ovulation, and in vitro fertilization as well as precocious growth and intersex. W...

32 CFR 2103.41 - Reproduction controls.

Science.gov (United States)

2010-07-01

... 32 National Defense 6 2010-07-01 2010-07-01 false Reproduction controls. 2103.41 Section 2103.41... Safeguarding § 2103.41 Reproduction controls. The Staff Secretary shall maintain records to show the number and... dissemination or reproduction limitations. ...

The Future of human reproduction

National Research Council Canada - National Science Library

Overall, Christine

1989-01-01

... Contradictions III SOCIAL POLICY QUESTIONS Pregnancy as Justification for Loss of Juridical Autonomy Sanda Rodgers 174 Prenatal Diagnosis: Reproductive Choice? Reproductive Control? Abby Lippman ...

The future of human reproduction

National Research Council Canada - National Science Library

Overall, Christine

1989-01-01

... Contradictions III SOCIAL POLICY QUESTIONS Pregnancy as Justification for Loss of Juridical Autonomy Sanda Rodgers 174 Prenatal Diagnosis: Reproductive Choice? Reproductive Control? Abby Lippman ...

Evaluation of Deep Discount Fare Strategies

Science.gov (United States)

1995-08-01

This report evaluates the success of a fare pricing strategy known as deep discounting, that entails the bulk sale of transit tickets or tokens to customers at a significant discount compared to the full fare single ticket price. This market-driven s...

Reproduction (II): Human Control of Reproductive Processes

Science.gov (United States)

Jost, Alfred

1970-01-01

Describes methods of intervening in reproduction of animals and humans (artificial insemination, contraception, ovular and blastodisc transplants, pre selection of sex, cloning) and discusses the social implications of their use with humans. (AL)

Maternal risk of breeding failure remained low throughout the demographic transitions in fertility and age at first reproduction in Finland.

Directory of Open Access Journals (Sweden)

Jianghua Liu

Full Text Available Radical declines in fertility and postponement of first reproduction during the recent human demographic transitions have posed a challenge to interpreting human behaviour in evolutionary terms. This challenge has stemmed from insufficient evolutionary insight into individual reproductive decision-making and the rarity of datasets recording individual long-term reproductive success throughout the transitions. We use such data from about 2,000 Finnish mothers (first births: 1880s to 1970s to show that changes in the maternal risk of breeding failure (no offspring raised to adulthood underlay shifts in both fertility and first reproduction. With steady improvements in offspring survival, the expected fertility required to satisfy a low risk of breeding failure became lower and observed maternal fertility subsequently declined through an earlier age at last reproduction. Postponement of the age at first reproduction began when this risk approximated zero-even for mothers starting reproduction late. Interestingly, despite vastly differing fertility rates at different stages of the transitions, the number of offspring successfully raised to breeding per mother remained relatively constant over the period. Our results stress the importance of assessing the long-term success of reproductive strategies by including measures of offspring quality and suggest that avoidance of breeding failure may explain several key features of recent life-history shifts in industrialized societies.