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Background Group formation and food sharing in animals may reduce variance in resource supply to breeding individuals. For some species it has thus been interpreted as a mechanism of risk avoidance. However, in many groups reproduction is extremely skewed. In such groups resources are not shared equally among the members and inter-individual variance in resource supply may be extreme. The potential consequences of this aspect of group living have not attained much attention in the context of risk sensitive foraging. Results We develop a model of individually foraging animals that share resources for reproduction. The model allows analyzing how mean foraging success, inter-individual variance of foraging success, and the cost of reproduction and offspring raising influence the benefit of group formation and resource sharing. Our model shows that the effects are diametrically opposed in egalitarian groups versus groups with high reproductive skew. For individuals in egalitarian groups the relative benefit of group formation increases under conditions of increasing variance in foraging success and decreasing cost of reproduction. On the other hand individuals in groups with high skew will profit from group formation under conditions of decreasing variance in individual foraging success and increasing cost of reproduction. Conclusion The model clearly demonstrates that reproductive skew qualitatively changes the influence of food sharing on the reproductive output of groups. It shows that the individual benefits of variance reduction in egalitarian groups and variance enhancement in groups with reproductive skew depend critically on ecological and life-history parameters. Our model of risk-sensitive foraging thus allows comparing animal societies as different as spiders and birds in a single framework.

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Objective The present study aimed to examine the association between paternal selective serotonin reuptake inhibitor (SSRI) use before conception and the risk of autism spectrum disorder (ASD) in offspring. Design A population-based cohort study. Methods We conducted a cohort study of 669 922 children born from 1998 to 2008, with follow-up throughout 2013. Based on Danish national registers, we linked information on paternal use of SSRIs, ASD diagnosed in children and a range of potential confounders. The children whose fathers used SSRIs during the last 3 months prior to conception were identified as the exposed. Cox regression model was used to estimate the HR for ASD in children. Results Compared with unexposed children, the exposed had a 1.62-fold higher risk of ASD (95% CI 1.33 to 1.96) and the risk attenuated after adjusting for potential confounders, especially fathers’ psychiatric conditions (HR=1.43, 95% CI 1.18 to 1.74). When extending the exposure window to 1 year before conception, the increased risk persisted in children of fathers using SSRIs only from the last year until the last 3 months prior to conception (HR=1.54, 95% CI 1.21 to 1.94) but not in children of fathers using SSRIs only during the last 3 months prior to conception (HR=1.17, 95% CI 0.75 to 1.82). We also performed stratified analyses according to paternal history of affective disorders and observed no increased ASD risk among children whose father had affective disorders. Besides, the sibling analysis showed that the ASD risk did not increase among exposed children compared with their unexposed siblings. Conclusions The mildly increased risk of ASD in the offspring associated with paternal SSRI use before conception may be attributable to paternal underlying psychiatric indications related to SSRI use or other unmeasured confounding factors.

A University of Adelaide study has identified the risk of major birth defects associated with assisted reproductive technologies.

OBJECTIVE: The authors examined the relationship between maternal antibody to toxoplasmosis and the risk of schizophrenia and other schizophrenia spectrum disorders in offspring. Toxoplasmosis is known to adversely affect fetal brain development. METHOD: In a nested case-control design of a large birth cohort born between 1959 and 1967, the authors conducted serological assays for Toxoplasma antibody on maternal serum specimens from pregnancies giving rise to 63 cases of schizophrenia and other schizophrenia spectrum disorders and 123 matched comparison subjects. Toxoplasma immunoglobulin (Ig)G antibody was quantified by using the Sabin-Feldman dye test. The Ig titers were classified into three groups: negative (

Introduction The use of assisted reproductive technology (ART) procedures has increased globally over the last three decades. Recent observational studies suggest that children conceived through ART may be at increased risk of asthma and atopic disease compared with children conceived naturally, but findings are mixed. We aim to synthesise the evidence on the impact of ART on the risk of asthma and atopic disease in the offspring. Methods and analysis We will identify relevant studies by searching MEDLINE, EMBASE, Cochrane Library, ISI Web of Science, CINAHL, Scopus, Google Scholar, AMED, Global Health, PsychINFO, CAB International and the WHO Global Health Library from 1978 to 2016. We will locate additional studies through searching databases of the proceedings of international conferences, contacting international experts in the field, and searching the references cited in identified studies. We will include analytic observational studies (cohort studies, case–control studies and cross-sectional studies) that have investigated the impact of any type of ART on offspring's asthma and atopic disease. Screening of identified records, data extraction from eligible studies and risk of bias assessment of eligible studies will be independently undertaken by two reviewers, with arbitration by a third reviewer. The Effective Public Health Practice Project will be employed for risk of bias assessment. Estimates from studies judged to be clinically, methodologically and statistically homogeneous will be synthesised using random-effects meta-analysis. Ethics and dissemination As this study is based solely on the published literature, no ethics approval is required. We will publish our findings in a peer-reviewed scientific journal and present the results at national and international scientific conferences. Protocol registration We will register a detailed protocol for the review with the International Prospective Register of Systematic Reviews (PROSPERO) prior to starting the review.

asexual

Facts and Information about Shark Reproduction. Shark Breeding Description.

Biology article by D G Mackean introducing vegetative reproduction in plants, covering bulbs, corms, rhizomes, runners, grafting, cuttings, and tissue culture, accompanied by detailed biological drawings

Difference between r and K Selection in Ecology

Facts and Information about Tiger Reproduction. Tiger Breeding Description.

Background Offspring of patients with anxiety or depression are at high risk for developing anxiety or depression. Despite the positive findings regarding effectiveness of prevention programs, recruitment for prevention activities and trials is notoriously difficult. Our randomized controlled prevention trial was terminated due to lack of patient inclusion. Research on mentally-ill parents’ perceptions of offspring’s risk and need for preventive intervention may shed light on this issue, and may enhance family participation in prevention activities and trials. Methods Qualitative data were collected through semi-structured interviews with 24 parents (patients with anxiety or depression, or their partners). An inductive content analysis of the data was performed. Five research questions were investigated regarding parents’ perceptions of anxiety, depression, and offspring risk; anxiety, depression, and parenting; the need for offspring intervention and prevention; and barriers to and experiences with participation in preventive research. Results Parental perceptions of the impact of parental anxiety and depression on offspring greatly differed. Parents articulated concerns about children’s symptomatology, however, most parents did not perceive a direct link between parent symptoms and offspring quality of life. They experienced an influence of parental symptoms on family quality of life, but chose not to discuss that with their children in order to protect them. Parents were not well aware of the possibilities regarding professional help for offspring and preferred parent-focused rather than offspring-focused interventions such as parent psycho-education. Important barriers to participation in preventive research included parental overburden, shame and stigma, and perceived lack of necessity for intervention. Conclusions This study highlights the importance of educating parents in adult health care. Providing psycho-education regarding offspring risk, communication in the family, and parenting in order to increase parental knowledge and parent–child communication, and decrease guilt and shame are important first steps in motivating parents to participate in preventive treatment.

Asexual reproduction occurs when an organism makes more of itself without exchanging genetic information with another organism through sex. In sexually reproducing organisms, the genomes of two parents are combined to create offspring with unique genetic profiles.

Attempts to find a new generation of pesticides to replace neonicotinoids have been dealt a potential blow.

ADVANTAGES : - Greater chance of fertilisation between sperm and egg so that excess gametes are not wasted.                                             -...

Different organisms reproduce via different methods. Some reproduce sexually while some reproduce asexually. The most common method of reproduction in humans is sexual reproduction.

An introduction to genetics that takes covers basic components of genetics such as DNA, genes, chromosomes and genetic inheritance.

Background Hyperemesis gravidarum is a serious condition affecting 0.8–2.3 % of pregnant women and can be regarded as a restricted period of famine. Research concerning potential long-term consequences of the condition for the offspring, is limited, but lack of nutrition in-utero has been associated with chronic disease in adulthood, including some cancers. There is growing evidence that several forms of cancer may originate during fetal life. We conducted a large study linking the high-quality population-based medical birth- and cancer registries in Norway, Sweden and Denmark, to explore whether hyperemesis is associated with increased cancer risk in offspring. Methods A registry-based nested case–control study. Twelve types of childhood cancer were selected; leukemia, lymphoma, cancer of the central nervous system, testis, bone, ovary, breast, adrenal and thyroid gland, nephroblastoma, hepatoblastoma and retinoblastoma. Conditional logistic regression models were applied to study associations between hyperemesis and risk of childhood cancer, both all types combined and separately. Cancer types with five or more exposed cases were stratified by age at diagnosis. All analysis were adjusted for maternal age, ethnicity and smoking, in addition to the offspring’s Apgar score, placental weight and birth weight. Relative risks with 95 % confidence intervals were calculated. Results In total 14,805 cases and approximately ten controls matched on time, country of birth, sex and year of birth per case (147,709) were identified. None of the cancer types, analyzed combined or separately, revealed significant association with hyperemesis. When stratified according to age at diagnosis, we observed a RR 2.13 for lymphoma among adolescents aged 11–20 years ((95 % CI 1.14–3.99), after adjustment for maternal ethnicity and maternal age, RR 2.08 (95 % CI 1.11–3.90)). The finding was not apparent when a stricter level of statistical significance was applied. Conclusions The main finding of this paper is that hyperemesis does not seem to increase cancer risk in offspring. The positive association to lymphoma may be by chance and needs confirmation.